Home

PERFORMANCE EVALUATION OF SOLAR SHADING SYSTEMS

1. Figure D 2 Shading position gt 0 Advanced glazing and shading devices database New entry Load database Save database r Thermal properties Visual transmittances tau g value dir Dir dir Dir gt diff Dir gt redir 05 0 682 0 0 0 452 0 5617 0 0 397 0 431 0 33 0 283 0 168 0 246 0 235 0 178 0 251 0 163 0 23 0 148 0 208 0133 0 0188 0 0 0 Diff sky Diff ground Inner surface reflectance rho Slat distance 0381 05 m Figure D 3 Shading position gt no shading after correction Appendix E Detailed drawing of the fa ade 0 175 w 5 O wo 3 oO wo N N 0 050 a e a oO q WQ foe S 19 650 0 175 a 20 000 Appendix F IESve models of the test room for Cases 1 2 3 and 4 CASE 2 CASE 1 T CASES CASE 4 Y F 2 Appendix G Examples of virtual images of the experimental rooms generated by ESve Radiance Figure G 1 Reference room under overcast sky Figure G 3 Test room under overcast sky for for Case 2 Daylight factor values Case 2 Daylight factor values 1464 2390 41116 ago 1599 2045 42567 41549
2. LS Gee total transmission 1 0 spec color trans 4 Sa ee lt tspeo gt diffuse transmission 1 0 spec color trans 1 0 tspec TAN A 7 i specular transmission 1 0 spec color trans tspec Figure 12 5 Diagram of how Radiance simulations handle the encountering of a surface of a trans material 15 Knowing the visual reflectance p and visual transmittance t of the glass that composes the glass lamellas it is possible to calculate the seven parameters that characterize the trans material according to 13 As stated before the lamellas are made of Antelio Silver glass from Saint Gobain For this glass the visual transmittance ty is 66 while the visual reflectance pv is 31 The specularity spec is the fraction of incident light that is immediately reflected in mirror and it is equal to the visual reflectance spec 0 31 70 The R reflectance G reflectance and B reflectance are the colour dependent reflectances As Antelio Silver is a clear glazing these values are all equal and can be represented by RGB reflectance The RGB reflectance may be calculated knowing the visual absorptance of the glass ay For Antelio Silver the light absorptance ay is a 1 0 66 0 31 0 03 12 2 According to Figure 12 5 the RGB reflectance may be calculated through the following equation a 1 spec 1 RGBrefl 12 3 0 03 1 0 31 1
3. RD 13 2 80 100 0 E gt at o gt 100 5 B REF Meas N 5 tt REF IESve Rad 5 4 TEST Meas E s TEST_IESve Rad 10 gt gt oc a 0 1 i i 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 11 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case 3 The values refer to May 3 at 10 07 10 0 0 0 a 10 0 30 0 o REF Relative Diference 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 12 Relative difference between the measured and simulated daylight factor for sunny sky at the working plane for the reference room for Case 3 The values refer to May 3 at 10 07 Figure 13 11 shows that closer to the window the daylight factor for sunny sky at the working plane is very high comparing to the values deeper in the room This is due to the incidence of direct sun in the room close to the window In order to represent the daylight levels for all the measuring points the logarithmic scale was chosen for the daylight factor for sunny sky axis Figure 13 12 illustrates that for the reference room the results from ESve Radiance simulations are slightly lower than the measurements especially in the back part of the room This would be expected as it also happened
4. 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 o 0 o 0 0 0 0 o 0 0 0 0 0 0 0 0 0 90000000000000000000000000000000000000000000000000000000 pppppppppppppppppppppppppppppppppppppppppppppppppppo90990 290000000000000000000000000000000000000000000000000000000 S99999999999999 S9S99S9S9999 999999999 999999999999999999999 90000000000000000000000000000000000000000000000000000000 S99999999999999 SSS99S999999999999999999999999999999999999 90000000000000000000000000000000000000000000000000000000 Figure C 3 Text file for the glass lamellas composed of SGG Antelio Silver C 3 7 Now that the text file for the glass lamellas is created it can be imported to W S database as previously referred on APPENDIX B B 2 Importing a text file and used as a slat shading system 8 In the Scattering layer window with SGG Antelio Silver activated set the geometric properties of the glass lamellas as shown in Figure C 4 the geometric properties could also be included in the text file As for the slat shading system also the glass lamellas the angle can be changed in order to create the different files to input in BuildingCalc LightCalc EE Scattering layers ID name Product name Type K E57 SGG Antelio Silver saa Sat shading device ae fon SGG_CoolLte SK147_IPS CootLite SK147 Slat shading device ae 1 659 Lamel metal 1 Slat shading device I This object is FROZEN and cannot be editted or un fro
5. 13 3 Case 3 13 3 1 Comparing 10 07 to 16 07 13 4 Case 4 14 Conclusions and further work References APPENDICES Appendix A Step by step example on how to use WIS and BuildingCalc LightCalc for the purpose of this dissertation A 1 How to obtain the software A 1 1 WIS A 1 2 BuildingCalc LightCalc A 2 Step by step example A 2 1 WIS How to create the text files with the properties of the window A 2 2 BuildingCalc LightCalc How to import the text files with the properties of the window generated in WIS Appendix B How to add a new shading system to WIS B 1 Inserting data manually B 2 Importing a text file Appendix C Example of how to model glass lamellas from glass pane properties in WIS Appendix D Tips on how to import the glass lamellas to BuildingCalc LightCalc Appendix E Detailed drawing of the fa ade Appendix F IESve models of the test room for Cases 1 2 3 and 4 Appendix G Examples of virtual images of the experimental rooms generated by lESve Radiance 73 75 76 76 78 79 80 83 84 86 87 A 1 A 1 A 1 A 1 A 1 A 2 A 6 List of Figures Figure 2 1 Heating transfer phenomena that occur on external above and internal below solar shading systems Figure 2 2 Schemes of external A interpane B and internal C venetian blinds Figure 2 3 Schemes of external A interpane B and internal C roller blinds Figure 2 4 Glass Lamellas Model CARRIER SYSTEM 1 from COLT manufacture
6. 6 13 3 3 Thermal transmittance coefficient The thermal transmittance coefficient U value is the amount of heat that passes through an element per unit area and per unit time when the temperature difference between the environments separated by the element is 1 Kelvin This parameter takes into account the surface resistances and the conduction convection and radiation phenomena It is usually defined in W m K 16 3 4 Solar heat gain coefficient The solar heat gain coefficient g value is the fraction of incident irradiance solar radiation incident on the glazing that enters the building and becomes heat in the space It includes both the directly transmitted portion and the absorbed and re emitted portion of solar radiation 6 3 5 Solar shading coefficient The solar shading coefficient SSC is sometimes defined as the ratio between the g value of a window system glazing solar shading device for a particular angle of incidence and the g value of a reference clear float glass 8mm thickness for the same angle of incidence 6 However in this dissertation it was assumed to be the ratio between the g value of the window system and the glazing initially selected as the reference In this way the reference glazing has a shading coefficient of 1 and it is easier to compare the performance of the different solutions Lower solar shading coefficients indicate higher performances 3 6 Visual shading coefficient The visual s
7. 6 43 SSG Antelio Esmeralda 96 B 08 043 08 9 11 224 571 5i 733 323 2 13 2727 24 30 6 45 SSG Retlectasol Green G 027 055 01 01 90 3 38 982 7 48 159 0 do 1 3 8 1 46 SSG Cool Lite KS147 96 07 035 09 057 8 0 23 580 1647 87 34 3 O 2992 20 BR 6 Combinations 47 PilkingArticBluesIntVerosolSiverScreenE DO 66 018 037 004 006 8 2 D 427 1121 66 25 1 03 2758 BN 49 6 48 PilkingArtic Blues ExtVerosolSiverScreenE DO 85 08 006 003 04 amp 8 868 216 104 306 107 8 08 1427 88 UT 6 49 PilkingArticBlue Int LuxaflexVenBlind4078 7 06 08 000 79 2 503 125 194 98 47 5 O 8779438 BM 5 50 PikingArticBlues ExtAlumbamelas 60 Bo 00 00 00 0 4 ABt 1080 1213 W 1 8 o 1671 39 2N 5 51 SGGReflectGreensIntVerosolRolerEDO 66 0 2 002 Bo 89 3 1017 BM 167 45 0159 9 o 204 99 88 6 52 SGGReflectGreen Ext erosolRoller ED 85 002 004 00 88 8 937 AA 100 V W 8 08 199 88 3 6 53 GGReflectGreen IntLuxeflexVenBiind4078 7 009 018 00 87 3 TM 186 1537 5 O02 10 03 202 61 30 6 54 SGGReflectGreen ExtAlumLamellas_ 60mm 85 00 00 0 00 0 6 68 169 1153 357 Ca 8 06 15600 630 319 6 For the systems that have orientable slats like venetian blinds and glass lamellas the properties refer to the system completely activated 90 slat postion The setpoint for cooling is 2220 so when the mechanical cooling is activated there are no hours above 2220 Total energy demand heating demand 2 5 lightning demand
8. 8 2 Case studies 8 2 1 Roller blinds 8 2 1 1 Data available from manufacture 8 2 1 2 How to use the data available from the manufacture 8 2 2 Venetian Blinds 8 2 2 1 Data available from manufacture 8 2 2 2 How to use the data available from the manufacture 8 2 3 Results and Discussion 9 Conclusions and further work PART B GLASS LAMELLA SYSTEMS COMPARING MEASUREMENTS WITH IESVE RADIANCE SIMULATIONS 10 Introduction and goal 11 The Daylight Laboratory at SBi 11 1 Description of the experimental rooms 11 1 1 Geometry 11 1 2 Landscape 11 1 3 The windows 11 1 4 Walls floor and ceiling 11 1 5 The furniture 11 1 6 The glass lamellas system 11 2 Measuring conditions 11 2 1 Case 1 11 2 2 Case 2 11 2 3 Case 3 11 2 4 Case 4 12 Modelling in ESve Radiance 12 1 The method 12 2 Settings and assumptions 12 2 1 The model 12 2 2 The surfaces properties 12 2 2 1 Plastic Material All surfaces excluding glazings and glass lamellas 12 2 2 2 Glass Material Glazings 12 2 2 3 Trans Material Glass Lamellas 12 2 3 The Sky Date Time 12 2 4 Image quality 13 Results and Comparison with the measurements 13 1 Case 1 13 1 1 The reference room 49 49 49 49 50 50 51 52 55 57 59 60 60 60 61 61 61 62 62 63 65 65 66 66 67 67 67 67 68 68 69 70 71 72 73 73 73 13 1 1 1 The working plane 13 1 1 2 The ceiling 13 1 2 The test room 13 1 2 1 The working plane 13 1 2 2 The ceiling 13 2 Case 2
9. 80 90 created for the system glazing shading in different slats positions see Figure A 11 Press Load button Press OK to return to the Glazings window 4 Press the button Save database and choose a name for the database 5 Now the created system can be added to the Project As defined this system has different positions only glazing or glazing shading with different slats angles During the yearly simulations BuildingCalc LightCalc will choose the most appropriate for each hour 6 Everytime a New entry is added before adding it to the Project the Database must be saved New database entry Description Glazing and shading RefGlazing Int LuxatlexVenetianBiin Shading device Blinds O Screen Glazing no shading O Load data from file Load data from file Enter user data li oa Load data Path Clear glazing D in s DTU thesisbuildingcalc_runtimetsimulations em Path Shading input ES E Es Doo es dE la amem Diln siDTUthesistuildingcale runtimetsimulatic D ln s DTU thesis ouildingcalc_runtimetsimulatic D Yn s DTU thesis buildingcalc_runtime simulatic D in s DTU thesis huildingcalc_runtimetsimulatic D in s DTU thesis buildingcalc_runtime simulatic __ D Un s DTU thesisbuildingcalc_runtimesimulatic D lin s DTU thesis buildingcalc_runtimetsimulatic pr Dtn sNTI thasiothitildinacale viirdimmaloirar istic su gt NB The visual transmittances for slat
10. ESVE RADIANCE SIMULATIONS 57 58 10 Introduction and goal As referred in the Part A of this dissertation the glass lamellas are a promising type of solar shading system besides acting as typical solar shading systems reducing the solar gains and consequently the cooling demand they may at the same time allow good indoor daylight levels thanks to the transparent properties of glass On the other hand during overcast days if they are correctly tilted they may slightly increase the indoor daylight especially on the back part of the room Some daylight measurements were performed in the Daylight Laboratory at SBi Danish Building Research Institute in Hgrsholm in Denmark regarding the research project Development of new solar shading systems based on daylight directing solar control glass lamellas lead by Steen Traberg Borup The daylight measurements in the Daylight Laboratory at SBi were performed in two experimental rooms reproducing office rooms one with an ordinary glass fa ade reference room and another one equal but equipped with a system of glass lamellas on its fa ade test room lluminance levels in specific points of both rooms working plane and ceiling were measured under different sky conditions and for different positions of the glass lamellas The results obtained for both rooms were compared and the performance of the glass lamellas evaluated The goal of Part B of this dissertation is to build the model of the
11. RGBrefl 12 4 RGBrefl 0 96 12 5 The transmissivity transm is a factor describing how much of the remaining light is transmitted through the glass Any remaining light will be reflected diffusely The transmissivity is calculated by tT 1 spec RGBreflec transm 12 6 0 66 1 0 31 0 96 transm 12 7 transm 1 0 12 8 The roughness rough is 0 0 for glass since it has a smooth surface The transmitted specularity tr spec is an index describing the distribution of the transmitted light that is not diffusely scattered It is 1 0 for a clear glass The ESve Radiance inputs for the Antelio Silver glass lamellas defined as trans material are presented in Table 12 3 Table 12 3 ESve Radiance inputs for Antelio Silver glass lamellas defined as trans material Element R refl G refl B refl Spec Rough Transm Tr spec Antelio Silver 0 96 0 96 0 96 0 31 0 0 1 0 1 0 Glass Lamellas 12 2 3 The Sky Date Time For Case 1 and Case 2 the CIE overcast sky was chosen for the simulations The simulations were performed for the 21 of December at 12 00 However the chosen date and time have no influence because the daylight level in the different measuring points was evaluated by the daylight factor 71 For Case 3 and Case 4 the option Sunny sky was chosen This corresponds to a completely clear sky with full sun 15 In these cases as the daylight level in the different measuring
12. Table 8 3 Data used in W S based on available data from the manufacture and assumptions previously suggested Table 8 4 Data available from the manufacture Table 8 5 Data used in W S based on available data from the manufacture and assumptions previously suggested Table 8 6 Comparison of the complete and simplified data of the solar shading systems Table 8 7 Comparison of results obtained with complete and simplified data Landscaped office building in Copenhagen Table 11 1 Reflectance values for the walls ceiling and floor of the experimental rooms Table 12 1 RGB reflectances specularity and roughness for the surfaces modelled as plastic material XV 12 21 21 21 24 27 29 32 35 44 45 47 49 50 51 51 54 54 61 69 Table 12 2 RGB transmissivities of the glazings of the experimental rooms Table 12 3 ESve Radiance inputs for Antelio Silver glass lamellas defined as trans material Table 12 4 Table showing the date time of the measurements for Case 3 and Case 4 and the correspondent date time set for the ESve Radiance simulations Table 13 1 Daylight factors at the working plane for the reference room for Case 1 measurements and ESve Radiance simulations Table 13 2 Reflectances defined in the ESve Radiance model and new reflectances used to evaluate the influence of the internal surfaces reflectances in the daylight factor in the back part of the room
13. accomplish the standard indoor environment requirements and are quite close to the admissible limit This means that in opposition to Copenhagen an office building in Lisbon always require an air conditioning system Even with an air conditioning system not all the solutions for the solar shading systems can fulfil the energy requirements for the cooling demand As referred before according to the Portuguese building code the cooling demand for an office building in Lisbon as the one studied can not be higher than 32kWh m year This means that some of the simulated solar shading systems can not be used in such a building in Lisbon For instance the internal roller blinds and the internal and interpane venetian blinds can never be used As in Lisbon there is a higher problem of overheating than in Copenhagen the use of the shading systems is needed during longer periods of time In this way as the shading systems reduce the daylight into the rooms it would be expected that the yearly energy needed for electrical lightning would be higher in Lisbon Indeed this is only true for roller blinds For systems composed of slats like the venetian blinds and glass lamellas as the solar altitude is higher in Lisbon than in Copenhagen the cut off angle is lower in Lisbon This means that in Lisbon higher levels of daylight can reach the room through the space between the slats Also the general luminance level of the sky is higher in Lisbon than in
14. 0 000 0 000 abs 6 0 000 0 000 0 000 0 000 0 000 abs 7 0 000 0 000 0 000 0 000 0 000 t_sol_o 0 000 0 000 0 000 0 000 0 000 t sol ii 0 000 0 000 0 000 0 000 0 000 r_sol_o 0 607 0 607 0 606 0 605 0 605 r sol i 0 312 0 312 0 312 0 313 0 318 t sol o d 0 000 0 000 0 000 0 000 0 000 t sol id 0 000 0 000 0 000 0 000 0 000 r sol od 0 392 0 392 0 391 0 389 0 384 r_sol_i_d 0 0621 0 0620 0 0618 0 0612 0 0599 t_vis_o 0 000 0 000 0 000 0 000 0 000 tvis_i 0 000 0 000 0 000 0 000 0 000 r_vis_o 0 696 0 696 0 695 0 694 0 693 rvis_i 0 243 0 243 0 243 0 245 0 254 t_vis_o d 0 000 0 000 0 000 0 000 0 000 tvis id 0 000 0 000 0 000 0 000 0 000 rvis_o d 0 630 0 630 0 629 0 626 0 618 rvis id 0 116 0 116 0 116 0 115 0 113 t uv o 0 000 0 000 0 000 0 000 0 000 t_uv_i 0 000 0 000 0 000 0 000 0 000 r_uv_o 0 000 0 000 0 000 0 000 0 000 r_uv_i 0 000 0 000 0 000 0 000 0 000 t_uv_o_d 0 000 0 000 0 000 0 000 0 000 t_uv_i_d 0 000 0 000 0 000 0 000 0 000 Figure A 7 Part of a text file from W S after being corrected A 2 2 BuildingCalc LightCalc How to import the text files with the properties of the window generated in WIS The way to use BuildingCalc LightCalc and how to define the different settings is described in detail in the BuildingCalc LightCalc userguide 11 In this step by step example only the way to import the text files generated with WIS will be presented 1 Start BuildingCalc LightCalc in Figure A 8 it is presented the BuildingCalc LightC
15. 0 50 150 00 0 800 0 800 0 00 0 40 whl 0 44 0 44 0 33 0 04 0 02 0 29 0 27 0 05 0 03 0 06 0 05 0 44 0 04 0 06 0 05 0 06 0 05 0 06 0 06 0 00 0 00 0 00 0 00 0 06 0 06 0 00 0 00 0 00 0 00 0 00 0 00 thermal properties optical properties 1D PositionType Product name Description tm a Wik pvi 0 33 0 33 0 29 0 67 0 67 0 43 0 43 0 64 0 64 0 73 0 74 0 33 0 67 0 73 0 74 0 73 0 74 0 40 0 04 0 62 0 83 0 66 0 78 0 40 0 04 0 62 0 83 0 78 0 40 0 40 0 40 ne Table 6 2 Cont Properties of the solar shading systems whose performances were evaluated thermal properties optical properties pst 0 25 0 26 0 39 0 20 06 08 06 34 ES 21 25 19 26 16 ES wl 0 66 0 45 0 19 0 54 D Postiontype Productrane Desorption thm ink Reall Ravi ch G External Glass Lamellas 400mm air gap between the glass lamellas and the glazing with free ventilation spectral data from glass 32 SGG Antelio Silver 500mm hard coating on the outer surface 800 100 087 087 063 3 GG_Antello Clear 500mm hard coating on the outer surface 8 00 100 087 0837 050 34 GG_Reflectasol Grey 500mm hard coating on the outer surface 800 100 087 087 088 35 Glav Stopsol Silverlight Green 500mm hard coating on the outer surface 800 100 087 087 090 solar contral glass replacing the refer
16. 129 0 128 abs 4 0 000 0 000 0 000 0 000 0 000 abs 56 14e 0176 13e 0176 12e 0176 11e 0176 11e abs 6 0 000 0 000 0 000 0 000 0 000 abs 75 47e 0175 46e 0175 45e 0175 43e 0175 39e P t_sol_o 2 40e 0162 40e 0162 39e 0162 38e 0162 36e t_sol_i 2 23e 0162 23e 0162 22e 0162 20e 0162 15e r_sol_o 0 607 0 607 0 606 0 605 0 605 r_sol_i 0 312 0 312 0 312 0 313 0 318 t sol o d2 40e 0162 40e 0162 39e 0162 38e 0162 36e t_sol_i_d2 23e 0162 23e 0162 22e 0162 20e 0162 15e r_sol_o_d 0 392 0 392 0 391 0 389 0 384 r_sol_i_d 0 0621 0 0620 0 0618 0 0612 0 0599 t_vis_o 3 85e 0163 84e 0163 84e 0163 82e 0163 77e t_vis_i 3 87e 0163 86e 0163 85e 0163 82e 0163 75e r_vis_o 0 696 0 696 0 695 0 694 0 693 r_vis_i 0 243 0 243 0 243 0 245 0 254 t_vis_o_d3 85e 0163 84e 0163 84e 0163 82e 0163 77e t_vis_i_d3 87e 0163 86e 0163 85e 0163 82e 0163 75e rvisod 0 630 0 630 0 629 0 626 0 618 rvistd 0 2136 0 136 0 116 0 215 0 312 t_uv_o 0 000 0 000 0 000 0 000 0 000 tiuv_i 0 000 0 000 0 000 0 000 0 000 r_uv_o 0 000 0 000 0 000 0 000 0 000 r_uv_i 0 000 0 000 0 000 0 000 0 000 t_uv_o_d 0 000 0 000 0 000 0 000 0 000 t_uv_i_d 0 000 0 000 0 000 0 000 0 000 r_uv_o_d 0 000 0 000 0 000 0 000 0 000 Figure A 6 Part of a text file from W S before being corrected prop 0 10 20 30 40 abs 1 0 262 0 263 0 264 0 266 0 268 abs 2 0 000 0 000 0 000 0 000 0 000 abs 3 0 130 0 130 0 130 0 129 0 128 abs 4 0 000 0 000 0 000 0 000 0 000 abs 5 0 000 0 000 0 000
17. 4 20m 5 40m 600m Figure 11 8 Plan of the Test room Reference room with the location of the measuring points r 3 00m t 0 85m 0 00m 0 00m 0 60m 1 20m 180m 3 00m 4 20m 540m 6 00m Figure 11 9 Section of the Test room Reference room with the location of the measuring points The measurements were performed for four different cases which correspond to different sky conditions and glass lamellas positions of the Test room see Figure 11 10 For each case measurements of the Test room and Reference room were performed simultaneously so the influence of the lamellas could be assessed Case 1 Case 2 Case 3 Case 4 Overcast Overcast Clear sky Clear sky lt STS J po NY Figure 11 10 Case studies sky conditions and position of the glass lamellas for the Test room 64 11 2 1 Case 1 Case 1 corresponds to an overcast situation the upper two lamellas were set in the 30 position while the others were opened For this case the daylight factor was determined for all the measuring points in the working plane and ceiling represented in Figure 11 8 and Figure 11 9 Around 300 measurements were performed under overcast skies and the average and standard deviation were calculated for each measuring point The overcast factor which is the ratio between the vertical and horizontal illuminances Evert Enor was calculated for each measurement and the results compared with the overcast factor for the CIE overcast sky
18. 5 and 15 For the ESve Radiance simulations performed for this dissertation the rendering options set are presented in Figure 12 6 Figure 12 6 Rendering options set for the ESve Radiance simulations performed for the experimental Customise Parameters Pixel sample rate es Ambient bounces Sampling threshold jposo Ambient accuracy joroo Source jitter frooo Ambient resolution h Source substructuring piso Ambient divisions jose Direct thresholding 0o50 Ambient super samples fios Direct certainty so Limit reflection Bo Direct relays Boo Limit weight jaoo2 Direct pretest density me B ooo Specular threshold o150 Ambient Value G 0 000 M Show tips B nee Cancel rooms of the Daylight Laboratory at SBi 72 13 Results and Comparison with the measurements In this chapter the results from the measurements performed in the experimental rooms of the Daylight Laboratory at SBi as well as the correspondent results from the ESve Radiance simulations are presented for the four cases described before Only the most relevant results are presented 13 1 Case 1 13 1 1 The reference room 13 1 1 1 The working plane In Table 13 1 the SBi measurements and ESve Radiance results for the daylight level at the working plane height 0 85m are presented for the reference room without glass lamellas under overcast sky The daylight levels are presented as daylight factors DLfactor For the measurements a
19. A 2 WIS Transparent System window Settings for the glazing ES Report Transparent System Detailed Guiput M i x M Figure A 3 WIS Calculate window 8 Click on the button Create A text file with the properties of the glazing will be generated Name it as ReferenceGlazing for instance and save it in a known folder to make easier its posterior use it is advised to store the WIS files in a folder named for instance WIS files inside the BuildingCalc LightCalc folder 9 Now that the text file representing the glazing is created similar text files must be generated for the glazing with the venetian blind different text files must be created for different slats angles A 3 Return to the Transparent System window and create a new record as presented in Figure A 4 Leave an air gap of 50mm between the glazing and the internal venetian blind do not set ventilation because it is an internal gap Choose the product Luxaflex 8 Perforation 2053 as the venetian blind EE Transparent system Jransparen sy sem name ReferenceGlazing IntVenetBlind Results Uva roo w m2K tilt angle 0 id 101 gular tocar tals um as solar direct transmittance 0 00 Te Ti 0 20 degrees sun 500 light transmittance 0 00 UY transmittance 0 00 Fyalue 0 00 Calculate Details Ventilation col rend Index Ra 0 Lal ETS width code flipp Type mm coating ed Pane vif Optithern SN 4fv 385 cu
20. Copenhagen As a consequence the yearly electrical lightning demand may be lower in Lisbon than in Copenhagen even with a higher need for use of shading systems in Lisbon 40 7 Daylight performance evaluation In chapter 6 Energy and indoor comfort evaluation using BuildingCalc LightCalc calculations were performed of the yearly electrical lightning demand to keep a general level of illuminance of 200lux and a level of 500lux in working areas In this chapter the goal will be to check how the daylight performance of different solar shading systems is for a specific situation certain time certain sky conditions and certain position of the solar shading system Using LightCalc instead of the combination BuildingCalc LightCalc the daylight factor will be evaluated at the working plane 7 1 Criteria and requirements There are different parameters that may be used to evaluate the daylight performance of a building the daylight factor the working plane illuminance the illuminance uniformity on the working plane the absolute luminance in the field of view and the luminance ratios between the working plane walls and screens 7 In this chapter the daylight performance of different solar shading systems combined with the reference glazing was assessed by the daylight factor at the working plane In an office building the general level of daylight factor should be around 2 while for working areas it should be 5 These values correspon
21. Roller Blinds 6 Verosol SilverScreen white EDOt HT 62 OM 008 001 001 4 08 817 205 106 35 108 8 08 1457 16 338 6 7 Verosol SilverScreen black EB01 HT 62 00 006 003 04 9 09 815 204 83 20 1 8 0 1375 76 3300 6 D Internal Venetian Blinds 8 Luxeflex venetian blind 8 Perforation 2053 58 038 03 04 006 9 01 447 49 208 137 800 P 02 5842 386 6308 5 9 Luxeflex venetian blind 8 Perforation 6127 58 O4 00 04 006 96 0 455 39 280 145 86 a4 02 5602 39 6579 5 20 Luxaflex venetian blind 8027 60 030 O61 000 00 7 O 444 A 19971380 T 2 02 6204 38 6163 5 21 Luxaflex venetian blind High Mirror 4078 58 023 04 000 00 9 0 445 Mo 1994 1325 703 2 02 5164 38 61 5 E Interpane Venetian Blinds 24 Luxatlex venetian blind 8 Perfor 2053 57 07 05 02 00 9 02 424 60 182 W M 14 02 3569 373 H 6 25 Luxaflex venetian blind 8 Perfor 6127 57 083 04 020 00 02 42 67 1871 48 dQ 14 02 3596 35 45 6 27 Luxaflex venetian blind High Mirror 4078 57 007 04 000 00 9 02 4 o 183 97 BH 14 02 3607 IB My 6 28 Luxaflex venetian blind Thermostop 2383 53 009 018 00 00 76 02 4283 58 1866 9 dO 14 02 3556 32 48 6 00 0 0 F External Venetian Blinds 29 Auminium lamellas 60mm 62 Ot 00 0 0 0 3 38 97 St 45 136 9 O 148 356 265 6 30 Aluminium lamellas 80mm 62 00 00 000 00 0 03 379 949 320472186 9 O 1880 36 24 6 31 Aluminium lamellas 100mm 62 00 00 000 00 0 03 379 949 1956 45 018 9 O 18 346 2759 6 For the systems that have orientable slats like venetian bind
22. Table 13 3 Daylight factors at the working plane in the reference room for Case 1 Results obtained from ESve Radiance simulations when increasing 5 the reflectance of the internal surfaces Table 13 4 Daylight factors at the ceiling for the reference room for Case 1 measurements and ESve Radiance simulations Table 13 5 Daylight factors at the working plane for the test room for Case 1 measurements and ESve Radiance simulations Table 13 6 Daylight factors at the ceiling for the test room for Case 1 measurements and lESve Radiance simulations Table C 1 Columns needed for the glass lamellas text file xvi 70 71 72 73 75 75 76 77 78 C 2 List of Symbols B Refl B tn c Cw Cr Cw DLfactor DLfactorSS E E Ep Ehor Ec E Emy Enw Evert FF g value G refl G tn L n OF PPD IR radiation IR Eina IR cout IR trans R R refl Area m Back surface of the solar shading system Blue Blue reflectance Blue transmissivity Slat crown height mm Specific heat capacity of the water J kg C Heat capacity of furniture J K Heat capacity J K Daylight factor Daylight factor for sunny sky IIluminance lux Total energy consumption kWh m year Energy consumption for heating kWh m year Global horizontal illuminance lux Energy consumption for cooling kWh m year Energy consumption for electrical lightning kWh m year Ener
23. W S website 41 A 1 2 BuildingCalc LightCalc BuildingCalc LightCalc is a tool being developed in MATLAB by the Civil Engineering Department at the Technical University of Denmark BYG DTU The original BuildingCalc LightCalc runs in MatLab but there is also available a runtime version that does no require MATLAB The newest version of BuildingCalc LightCalc2 3 1f is not available in the web and but it can be obtained at BYG DTU contact Christian Anker Hviid phD student at BYG DTU e mail address cah byg dtu dk A 2 Step by step example The following example refers to an internal venetian blind applied on the glass fa ade of the landscaped office building described on the chapter 5 Case study Landscaped Office Building of this report A 1 A 2 1 WIS How to create the text files with the properties of the window To simulate an internal venetian blind in BuildingCalc LightCalc different text files must be created in WIS one with the properties of the glazing unit without the shading and others with the venetian blind activated for different slat angles 1 Start WIS In Figure A 1 it is presented the W S interface E Advanced Windows Information System WIS go Ed ea a Environm Specular pane Transparent Fi Ala ie Suppliers External programs A Spacers Groups Calculation settings E docs Figure A 1 W S interface main window 2 Click on the Scattering layer button A database with t
24. a text file from W S after being corrected Figure A 8 BuildingCalc LightCalc interface Figure A 9 Glazings window from Building menu Figure A 10 New entry window Figure B 1 Table where the spectral data for the new shading system are defined valid for roller blinds and slat shading systems Figure B 2 Table where the integrated data for a new roller blind system are defined for different angles of incidence Figure B 3 Table where the integrated data for a new slat shading device are defined only normal angle of incidence xiii 79 79 81 81 82 83 83 84 A 2 A 3 A 4 A 5 A 6 A 6 A 7 A 7 A 8 B 1 B 2 Figure C 1 Specular pane window with SGG Antelio Silver pane active Figure C 2 Calculate window Figure C 3 Text file for the glass lamellas composed of SGG Antelio Silver Figure C 4 Geometric properties for the SGG Antelio Silver glass lamellas Figure D 1 Shading position gt no shading before correction Figure D 2 Shading position gt 0 Figure D 3 Shading position gt no shading after correction Figure G 1 Reference room under overcast sky for Case 2 Daylight factor values Figure G 2 Reference room under sunny sky for Case 4 May 18th 2007 at 13 07 IIluminance values lux Figure G 3 Test room under overcast sky for Figure G 4 Reference room under sunny sky for Case 4 May 18th 2007 at 13 07 IIluminance values lux
25. absorptance Visual absorptance Ultraviolet absorptance Temperature increase needed for the production of hot water C Angle of incidence Solar azimuth angle Profile angle Thermal conductivity W mK Solar reflectance Visual reflectance Ultraviolet reflectance Solar transmittance Visual transmittance Ultraviolet transmittance xviii PART A ENERGY AND DAYLIGHT PERFORMANCE EVALUATION OF SOLAR SHADING SYSTEMS 1 Introduction 1 1 Background Energy savings are essential for the general long term solution of the problems with use of energy from fossil fuels In buildings to maintain a good indoor environment energy is used for heating cooling and electrical lighting This requirement for indoor comfort is especially important in large office buildings it is known that the indoor comfort has a large influence on the workers motivation and efficiency levels In this way if the office buildings are not carefully designed the yearly total energy consumption can reach very high levels To assure a high energy performance of buildings not only the insulation of the building envelopment is important but also other components as the ventilation heating and cooling systems are significant However the weakest parts of the buildings are the windows They are incorporated in buildings to provide indoor daylight and a good view out In theory larger the windows are l
26. be Figure D 3 Advanced glazing and shading devices database New entry Load database Save database Description Shading position SGG Antelio Silver No shading Update Greyed out boxes are not used in simulation r Thermal properties Visual transmittances tau Database Profile angle g value dir Dir gt dir Dir gt diff Dit gt redir Odeg 05 0 682 0 0 10deg 0 63 0 0 20 deg 0 0 30 deg 40deg 50deg 60 deg Project a0 deg ee 90 deg 0 g value dif 0 45 U value VWin2K 0 638 Inner surface reflectance rho Slat distance Slat width 019 amp 05 m 05 m Figure D 1 Shading position gt no shading before correction D 1 Advanced glazing and shading devices database Newentry Loaddatabase Save database Description Shading position Greyed out boxes are not used in simulation Thermal properties Visual transmittances tau Database g value dir Dir dir Dir diff Dir redir 05 0 682 0 0 St ntelio S 0 452 0 5617 0 0 397 0 431 0 33 0 283 0 246 0 105 0178 0 0 163 0 148 0 133 0 0 g value dif Diff ground 0 288 U value vWim2K 0 638 Inner surface reflectance rho Slat distance Slat width 0381 05 jm 05 m
27. cases measurements and simulations the daylight factor at the working plane in the back of the room is the same with or without lamellas This is one of the advantages of the glass lamellas sytems they allow homogenising the daylight factor along the depth of the room see Figure 13 5 77 a REF Meas o REF IESve Rad 4 TEST Meas A TEST IESve Rad Daylight Factor 3 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 5 Measured and simulated daylight factors for the working plane for Case 1 for both reference and test room 13 1 2 2 The ceiling In Table 13 6 the SBi measurements and ESve Radiance results for the daylight factor DL factor at the ceiling are presented for the test room without glass lamellas under overcast sky see comments above Table 13 1 for better understanding Table 13 6 Daylight factors at the ceiling for the test room for Case 1 measurements and JESve Radiance simulations window m i o C im DL factor Stdev DL factor j Diference 60 k 06 L 18 24 0089 31 202 30 16 0 050 TS 42 12 0032 og 2350 Pp 54 o9 027 o6 333 For this case also the daylight factor at the ceiling in the back of the room is higher for the measurements than for the ESve Radiance simulations Once again the performance of the lamellas according to the me
28. contact Christian Anker Hviid phD student at BYG DTU e mail address cah byg dtu dk 39 ESve IES lt Virtual Environment gt version 5 8 Integrated Environmental Solution Ltd Glasgow UK 2007 http www iesve com July 2007 40 Parasol v3 0 Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University 2001 http www eere energy gov buildings tools_directory software cfm ID 443 pagename alpha list July 2007 41 WIS Windows Information System version 3 0 1 TNO Building and Construction Research Delft The Netherlands 2006 http www windat org July 2007 90 APPENDICES Appendix A Step by step example on how to use W S and BuildingCalc LightCalc for the purpose of this dissertation A 1 How to obtain the software A 1 1 WIS WIS is a tool built in Microsoft Access and it can be downloaded for free from the website http Awww windat org 41 where technical support and user instructions are also available To assure a complete download of WIS the steps next presented should be followed 1 Download WIS 3 0 1 setup file 2 Download Service Pack 2 This tool fixes some already detected bugs 3 Update the Original Database 3 1 Download Update Database 2004 and Update Database October 2006 3 2 Import the products from the Update Databases to the Original Database Detailed instructions on how to do the referred steps are described on the
29. exterior solutions is 0 60W m K for vertical elements and 0 45W m K for horizontal elements for Lisbon climate area 12 Thus 0 4W m2K was used for whole the exterior solutions This means a new UA value of 61 85W K 23 To avoid overheating during the winter months December January and February there was a need to set venting outside the working hours night and weekends also during these months However the cooling setpoint is 22 C instead of 20 C which was set for the other months A cooling setpoint of 20 C for venting during night and weekends in winter would lead to an increase on the heating demand 5 3 Location and weather files Also the location and weather data files must be loaded in BuildingCalc LightCalc The location data for Copenhagen and Lisbon are presented on Table 5 4 Table 5 4 Location of Copenhagen and Lisbon Portugal Denmark Lisbon Copenhagen Lattitude 38 72 N Longitude 9 13 W Time meridian 0 The weather data for Copenhagen is based on the Danish design reference year 9 The weather data for Lisbon is based on the TRY Test reference year 19 24 6 Energy Performance and indoor comfort evaluation 6 1 Requirements and expected results 6 1 1 Energy frame 6 1 1 1 Denmark According to the Danish Building code 2 the energy frame for office buildings is given by E 95 2200 A kWh m year 6 1 where A is the internal floor area in m E in kWh m is the yearl
30. fo A a eee DE red vi TT do S Bessa OT JM E O O O RS O E E er m 0 O E E Return Select transparent system name Record ugeg EE PJPP of 29 Figure A 4 WIS Transparent System window Settings for the glazing internal venetian blind 10 Open the Scattering layer window and activate the record for the Luxaflex 8 Perforation 2053 In the menu Geometry set the slat angle as 90 see Figure A 5 11 Click on the button Calculate A new window will appear answer Yes Next another window will be presented click on Return 12 Come back to the Transparent System window and press the button Calculate A window as the one in Figure A 3 will appear check the boxes as they are checked in Figure A 3 Press Create The text file for the glazing with the internal venation blind with the slats angle of 90 is now created Save it as 90 tmp txt and store it in a folder named Luxaflex Venetian Blind 8 Perf 2053 inside the folder WIS files referred on 8 13 Repeat steps 10 to 12 only varying the slats angle Create text files for the following slats angles 90 80 60 40 20 0 20 40 60 80 90 and store them in the folder Luxaflex 8 Perforation 2053 referred on 12 A 4 EE Scattering layers Product name E Luxaflex Venetian Blind 8 Perforation 2053 Luxaflex Venetian Blind 8 Perforation 2053 Slat shading device E 11 Luxaflex Venetian Blind 8 Perforation 2344 Luxafl
31. it is not worthy to have a solar shading system besides the higher total energy consumption the indoor natural light level is lower and the view out is obstructed which are the main purposes of having a window A solution that provides a balance between solar gains and daylight level must be found It is very important that the most appropriate solar shading system is chosen for each situation and this procedure should be simple and done early in the design phase The Department of Construction and Architecture from Lund University already developed a tool Parasol for this purpose Parasol is a user friendly interface which is able to calculate the properties of windows systems composed of different solutions of glazings and shading devices The different window systems can be integrated in a simple model of a room and yearly simulations can be performed giving as a result the room yearly energy demands for heating and cooling In this dissertation the combination of WIS Window Information System with BuildingCalc LightCalc will be used WIS is a tool that calculates the properties of window systems based on the properties of their components WIS includes databases with detailed information for some windows components available in the market as glass panes shading systems frames and spacers BuildingCalc LightCalc is a tool that is able to assess the performance of buildings in which windows from W S can be integrated and as in Parasol year
32. kWh m year Type of energy Heating Cooling Hot water no specific limits are defined for mechanical ventilation and lightning energy demands As referred before in chapter 6 1 1 1 Denmark of this dissertation the energy demand for mechanical ventilation and hot water is constant for the different solar shading systems and equal to 17kWh m2year In this way this value can be subtracted to 121kWh m year and 104kWh m year can be obtained This last value is the maximum total energy available for heating cooling and lightning in order to fulfil the Portuguese requirements In spite of being extremely high for nowadays concerning of saving energy this is the standard requirement in Portugal 6 1 2 Indoor comfort BuildingCalc LightCalc is able to calculate two different parameters that show the performance of the simulated building regarding the indoor comfort These two parameters are the hours of overheating above a specified temperature and the PPD index According to the indoor environment standard 14 for a category II landscaped office building the working hours above 26 C during one whole year should not be more than 108 At the same time daily weekly and monthly criteria is set for instance no more than 24min of overheating per day or 2 hours per week should occur The objective of this is to keep a good level of comfort during all the working days of the year avoiding for example summer days in which the temperature is
33. metallic b black 0 50 0 15 0 160 0 810 0 05 0 75 50mm air gap between the glazing and the shading with free ventilation half transparent OF 4 f metallic b white 0 50 0 15 0 160 0 830 0 06 0 74 half transparent OF 4 f metallic b black 0 50 0 15 0 160 0 810 0 05 0 75 50mm air gap between the glazing and the shading w 25mm c 0mm p 20mm grey metallic 0 22 100 00 0 670 0 670 0 06 0 40 w 25mm c 0mm p 20mm black 0 22 100 00 0 640 0 640 0 06 0 05 w 25mm c 0mm p 20mm supermat grey 0 22 100 00 0 819 0 819 0 00 0 56 w 25mm c 0mm p 20mm f high mirror b grey stone 0 22 100 00 0 710 0 680 0 00 0 83 w 25mm c 0mm p 20mm metallic grey 0 22 100 00 0 392 0 392 0 00 0 69 w 25mm c 0mm p 20mm white 0 22 100 00 0 800 0 260 0 00 0 70 placed on the outer gap 16mm distance from outer pane and 13mm distance from the middle pane w 16mm c 0mm p 12mm grey metallic 0 22 100 00 0 670 0 670 0 06 0 40 w 16mm c 0mm p 12mm black 0 22 100 00 0 640 0 640 0 06 0 05 w 16mm c 0mm p 12mm supermat grey 0 22 100 00 0 819 0 819 0 00 0 56 w 16mm c 0mm p 12mm f high mirror b grey stone 0 22 100 00 0 710 0 680 0 00 0 83 w 16mm c Omm p 12mm white 0 22 100 00 0 800 0 260 0 00 0 70 50mm air gap between the glazing and the shading with free ventilation integrated data based on Warema manufacture w 60mm c 5mm p 42mm 0 50 150 00 0 800 0 800 0 00 0 40 w 80mm c 5mm p 42mm 0 50 150 00 0 800 0 800 0 00 0 40 w 100mm c 10mm p 92mm
34. points was evaluated by the illuminance lux the global horizontal illuminance for each simulation must be determined and compared to the one for the correspondent measurement The days and time of the simulations were defined the same as the instants of measurements taking into account that the measurements occurred during May 3 and 18 in which the summer time in set For the simulations the real solar time which in Denmark is one hour less had to be set In Table 12 4 the instants of the measurements and the correspondent instants set in the simulations are presented Table 12 4 Table showing the date time of the measurements for Case 3 and Case 4 and the correspondent date time set for the ESve Radiance simulations Date time set for the lESve Radiance simulation real solar time Case Date time of the measurement number summer time May 3 10 07 May 3 09 07 Case 3 May 3 13 07 May 3 12 07 May 3 16 07 May 3 15 07 May 187 10 07 May 187 09 07 Case 4 May 187 13 07 May 187 12 07 May 187 16 07 May 187 15 07 12 2 4 Image quality The rendering options are a group of different parameters that can be adjusted to guarantee the accuracy of the image generated by ESve Radiance The optimal rendering option settings are the ones that provide the highest possible accuracy in an acceptable rendering time More information about the rendering options is available in
35. rooms for Case 2 Figure 13 11 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case 3 The values refer to May 3 at 10 07 Figure 13 12 Relative difference between the measured and simulated daylight factor for sunny sky at the working plane for the reference room for Case 3 The values refer to May 3 at 10 07 Figure 13 13 ESve Radiance image Test room under sunny sky for Case 3 May 3 2007 at 10 07 Illuminance Figure 13 14 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case3 The values refer to May 3rd at 10 07 Figure 13 15 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case3 The values refer to May 3rd at 16 07 Figure 13 16 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case4 The values refer to May 18 at 13 07 Figure A 1 WiS interface main window Figure A 2 WIS Transparent System window Settings for the glazing Figure A 3 WIS Calculate window Figure A 4 WIS Transparent System window Settings for the glazing internal venetian blind Figure A 5 Scattering layer window Luxaflex 8 Perforation 2053 record is activated Figure A 6 Part of a text file from W S before being corrected Figure A 7 Part of
36. the different components of a window solar shading systems panes of glass frames and spacers This information which includes geometrical thermal and spectral optical properties of the components can be added by the manufactures and it is a precious help for the designers However still few manufactures have their information available on WIS databases It is also possible for the designer to add products to the database But due to a lack of information about the properties of products by the solar shading systems manufactures this process is sometimes difficult for the designer The optimum solution would be that the manufactures knew the properties of their solutions and had them in databases This is a problem essentially regarding the solar shading systems manufactures For the glass this information is easier to find One solution would be to set up a product standard that requires documentation of spectral and angular optical data and that also requires the manufactures to CE mark the products sold in the European Union 4 1 2 BuildingCalc and Light Calc In this dissertation BuildingCalc LightCalc was used in two different versions combined simulations for determination of the heating cooling and lightning needs number of hours of overheating and PPD index and light simulations to evaluate the daylight performance of the different solar shading systems under critical sky conditions In this software the simulation of thermal con
37. was used the name of the solar shading system is preceded by the word SIMPLIFIED The results show that the simplifications made have a very slight influence on the performance of the solar shading systems the analysed parameters do not have significant variations For instance the yearly total energy consumption of the landscaped office room has a maximum variation of 8 when comparing the use of complete data with the use of simplified data However the small differences on the results can have different reasons For example the differences on the heating demand depend directly on the thermal properties defined for the shading For instance for the internal roller blind Veroso Roller 818 000 an IR transmissivity of O was defined for the simplified model while the real product has an IR transmissivity of 0 158 In this way it is expected that the U value of the glazing combined with the internal blind for the simplified model is lower than the real one Consequently the heating demand for the office room will be lower when using the simplified data Regarding the need for electrical lightning the results show that the electrical lightning demand is lower when simplified data is used which means that more natural light is entering the room with the simplified model The reason for this can be the way how the transmittance was defined when different than zero it was assumed that all of the transmittance is direct and there is no diffus
38. which has the complete data available in W S the second refers to an external venetian blind made of aluminium lamellas and their complete properties are not available on WIS In this way for this last case the results obtained using simplified data can not be compared to the ones with complete data 8 2 2 1 Data available from manufacture In Table 8 4 the data available for both cases is presented 50 Table 8 4 Data available from the manufacture Warema aluminium lamellas 60mm Luxaflex Venetian Blind High Mirror 4078 Raffstoren 94 A6 RAL 9006 thickness 0 5mm slat chord width 60mm crown height 5mm slat pitch 52mm thickness 0 22mm slat chord width 25mm crown height 2mm slat pitch 20mm ts 0 ts 0 f ps 0 83 ps 0 4 tv 0 Ost R pv 0 83 py front surface metallic both surfaces painted back surface non metallic As the lamellas are placed outside their surface is exposed to the exterior environmental conditions and easily their reflectance can be long term reduced This situation must be taken into account and the original reflectance given by the manufacture must be decreased the original value was 0 51 8 2 2 2 How to use the data available from the manufacture The data used in WIS based on available data from the manufacture and assumptions previously suggested are presented in Table 8 5 Table 8 5 Data used in WIS based on available data from the manufacture and assumptions
39. with Cases 1 and 2 Similar to Case 1 and 2 in the back part of the room the values from simulations are around 35 lower than the simulations As a consequence for the test room the results from ESve Radiance simulations are also lower than the measurements 81 As in this case Case 3 the measurements refer to a single instant May 3 at 10 07 it is more difficult to fit measurements with simulations During the measurements many factors may vary The sky may not be completely clear with full sun some clouds may exist Also the distribution of a real clear sky is not the same as the standard clear sky Also other factors as the equipment and human errors are inherent to measurements The important conclusion is that during sunny days when the glass lamellas are completely closed acting as a solar shading system they reduce slightly the indoor daylight inside the room see measurements and simulations for reference and test rooms in Figure 13 11 However if compared to typical solar shading systems this decrease is insignificant when completely activated typical solar shading systems may totally block the light to enter into the room It is also important to refer that the decrease in daylight caused by the lamellas is similar when comparing measurement with ESve Radiance simulations see Figure 13 11 but take into account that the daylight factor for sunny sky is represented in logarithmic scale in this way at first glance it
40. xiv C 1 C 2 C 3 D 1 D 2 D 2 G 1 G 1 G 1 List of Tables Table 2 1 Examples of manufactures for the solar shading systems studied Table 5 1 Composition of the reference glazing for the test room fa ade Table 5 2 Properties of the reference glazing for the test room fa ade Table 5 3 Properties of the equivalent frame for the test room fa ade Table 5 4 Location of Copenhagen and Lisbon Table 6 1 Maximum values for energy consumption calculated according to the Portuguese building code Table 6 2 Properties of the solar shading systems whose performances were evaluated Table 6 3 Energy and indoor comfort performance of the landscaped office room in Copenhagen for the reference glazing and for the combination of the reference glazing with the different solar shading systems Table 6 4 Energy and indoor comfort performance of the landscaped office room in Lisbon for the reference glazing and for the combination of the reference glazing with the different solar shading systems Table 7 1 Cut off angle as for the different slat systems on December 21 at 12 00 o clock the profile angle is 11 2 for Copenhagen and 27 3 for Lisbon Table 7 2 Daylight factors calculated in point A x 10m y 8m z 0 85m with different solar shading systems applied on the fa ade of the office building Table 8 1 Tips on how to use simplified data from manufactures Table 8 2 Data available from the manufacture
41. 0 396 The results obtained for the overcast factors are presented in Figure 11 11 all the values are inside the range 0 38 0 42 but most part of them are higher than the CIE overcast sky which means that during the measurements the distribution of the sky is slightly different from the one the characterizes the CIE overcast sky 0 43 SBi OvercastFactor CE Overcast Sky OF 0 396 Upper limit 0 42 Lower limit 0 38 Overcast factor 0 37 1 51 101 151 201 251 Measurement number Figure 11 11 Overcast factor for the measurements performed for Case 1 11 2 2 Case 2 Case 2 is similar to Case 1 Only the position of the lamellas is different all the lamellas are set with an angle of 30 Also around 300 measurements under overcast skies were performed in order to obtain the daylight factors for all the measuring points represented in Figure 11 8 and Figure 11 9 The overcast factors during the measurements are presented in Figure 11 12 Once again in most measurements the overcast factor was higher than the one for the CIE overcast sky 65 0 43 0 42 amp jdi SBi OvercastFactor Fo CIE Overcast Sky OF 0 396 E Upper limit 0 42 0 40 Lower limit 0 38 7 q o o 0 39 gt 6 0 38 0 37 T T J T T 1 51 101 151 201 251 Measurement number Figure 11 12 Overcast factor for the measurements perf
42. 1 31 20 i A Internal Roller Blinds 1 Verosol Roller 818 000 UT light grey 0 60 0 40 0 82 0 33 0 49 95 0 50 3 78 9 94 182 11 0 54 17 83 3 62 27 42 7 1S SIMPLIFIED Verosol Roller 818 000 UT light grey 0 57 0 36 0 73 0 33 0 49 95 0 45 3 65 9 57 156 10 0 47 16 19 3 53 25 47 T 11 Verosol SilverScreen black EB01 HT 0 51 0 25 0 51 0 04 0 06 94 0 41 7 28 18 61 101 9 0 41 12 38 6 82 29 83 8 11S SIMPLIFIED Verosol SilverScreen black EBO1 HT 0 57 0 27 0 55 0 04 0 06 95 0 49 6 81 17 51 112 9 0 49 13 24 6 38 29 66 8 Cc External Roller Blinds 17 Verosol SilverScreen black EBO1 HT 0 62 0 03 0 06 0 03 0 04 95 0 78 6 31 16 56 0 8 0 78 2 97 6 17 19 18 8 17S SIMPLIFIED_Verosol SilverScreen black EB01 HT 0 62 0 03 0 06 0 04 0 06 95 0 78 6 00 15 78 0 8 0 78 2 97 5 86 18 40 8 D Internal Venetian Blinds 21 Luxaflex venetian blind High Mirror 4078 0 58 0 23 0 47 0 00 0 00 90 0 46 4 51 11 72 214 12 0 49 19 79 4 30 31 02 7 21S SIMPLIFIED_Luxaflex venetian blind High Mirror 4078 0 59 0 25 0 51 0 00 0 00 90 0 47 4 45 11 58 173 11 0 50 17 60 4 25 28 72 7 F External Venetian Blinds 29 SIMPLIFIED_Warema_Aluminium lamellas_60mm 0 62 0 01 0 02 0 00 0 00 0 0 67 4 14 11 00 0 8 0 67 4 00 4 09 14 88 8 1 For the venetian blind the properties refer to the system completely activated 90 slat position 2 The setpoint for cooling is 22 C so when the mechanical cooling is activated there are no hours above 22 C Total energy demand heating demand 2 5 lightning demand Total ener
43. 10 Daylight Factor 3 11 PPD index Method to evaluate the performance of different solar shading systems 4 1 The Sofware used Relation between WIS and BuildingCalc LightCalc 4 1 1 WIS 4 1 2 BuildingCalc and Light Calc Case study Landscaped office building 5 1 Settings for Copenhagen 5 1 1 General information and dimensions 5 1 2 The window glazing and frame 5 1 3 Type of construction and furniture 5 1 4 Systems 5 2 Different settings for Lisbon 5 3 Location and weather files Energy Performance and indoor comfort evaluation 6 1 Requirements and expected results 6 1 1 Energy frame 6 1 1 1 Denmark 6 1 1 2 Portugal 6 1 2 Indoor comfort 6 2 Characterization of the solar shading systems used 6 3 Results 6 4 Discussion of the Results 6 4 1 Copenhagen 6 4 1 1 The reference system 6 4 1 2 The different solar shading systems 6 4 2 Lisbon 6 4 2 1 The reference system 6 4 2 2 The different solar shading systems Daylight performance evaluation 7 1 Criteria and requirements 7 1 1 Roller blinds 7 1 2 Slat systems venetian blinds and glass lamellas 7 1 3 Reference glazing and solar control glazings 7 2 Results 7 3 Discussion of the results Some tips on how to overcome the lack of data available for solar shading systems 8 1 General Assumptions viii 15 15 16 16 17 17 19 19 19 20 21 22 23 24 25 25 25 25 26 27 28 31 37 37 37 38 39 39 40 41 41 42 42 44 44 45 47 47
44. 13 2 the new reflectances are presented The results are presented in Table 13 3 The relative difference is the back part of the room decreased from around 30 to 20 which is significant but still can not explain all the difference between simulations and measurements 74 Figure 13 2 Components of daylight a direct sun b direct sky c externally reflected and d internally reflected 22 Table 13 2 Reflectances defined in the ESve Radiance model and new reflectances used to evaluate the influence of the internal surfaces reflectances in the daylight factor in the back part of the room Element es in New reflectances Inner walls 0 62 0 67 Floor 0 11 0 16 Ceiling 0 88 0 93 Tables 0 80 0 85 Table 13 3 Daylight factors at the working plane in the reference room for Case 1 Results obtained from lESve Radiance simulations when increasing 5 the reflectance of the internal surfaces IESve Radiance DL factor Another reason for different ESve Radiance results and measurements may be the sky The real overcast sky is never equal to the CIE overcast sky defined by the standards and used for daylight simulations 13 1 1 2 The ceiling In Table 13 4 the SBi measurements and ESve Radiance results for the daylight factor DLfactor at the ceiling are presented for the reference room without glass lamellas under overcast sky see comments above Table 13 1 for better unde
45. 2 in Copenhagen and 27 3 in Lisbon The cut off position for the solar shading systems composed of slats will be calculated for this time 42 To calculate the cut off angle cc first the profile angle 8 must be determined The profile angle is the projection of the solar altitude angle on a vertical plane perpendicular to the fa ade However as 12 00 o clock was chosen the solar azimuth angle is approximately 0 and the profile angle was assumed to be equal to the solar altitude angle see Figure 7 3 Figure 7 3 Drawing of a building fa ade with the representation of the solar altitude angle B solar azimuth angle y and profile angle 0 The cut off angle oc may be calculated by the following equation valid for o gt 0 For a better understanding see Figure 7 4 sina x cosa xtano 2 7 1 2 2 2 where a is the cut off angle in degrees is the profile angle in degrees wis the width of the slats inmm and pis the distance between slats in mm T v p to VA H K Figure 7 4 Drawing of a slat system showing the profile angle 0 the cut off angle ac the slats width w and the distance between slats p In Table 7 1 the cut off angle is presented for each slat system and for both Copenhagen and Lisbon 43 Table 7 1 Cut off angle as for the different slat systems on December 21 at 12 00 o clock the profile angle is 11 2 for Copenhagen and 27 3 for Lisbon Copenhagen Lis
46. 3 External Venetian Blinds Aluminium lamellas 60mm Aluminium lamellas 80mm Aluminium lamellas 100mm IR eou IRemna qs ps 50mm air gap between the glazing and the shading ultra transparent OF 40 f metallic b light grey 0 18 0 20 0 510 0 811 0 44 0 34 ultra transparent OF 40 f metallic b Beige 0 18 0 20 0 510 0 811 0 44 0 34 ultra transparent OF 40 f metallic b dark grey 0 18 0 20 0 510 0 811 0 20 0 35 black out OF 0 f metallic b light grey 0 18 0 20 0 285 0 807 0 04 0 68 black out OF 0 f metallic b dark grey 0 18 0 20 0 285 0 807 0 02 0 68 transparent OF 23 f metallic b light grey 0 23 0 20 0 506 0 802 0 29 0 44 transparent OF 23 f metallic b dark grey 0 23 0 20 0 506 0 802 0 28 0 44 half transparent OF 2 f metallic b light grey 0 18 0 20 0 342 0 767 0 06 0 66 half transparent OF 2 f metallic b dark grey 0 18 0 20 0 342 0 767 0 04 0 66 half transparent OF 4 f metallic b white 0 50 0 15 0 160 0 830 0 06 0 74 half transparent OF 4 f metallic b black 0 50 0 15 0 160 0 810 0 05 0 75 placed on the outer gap 9mm distance from outer pane and 5mm distance from the middle pane ultra transparent OF 40 f metallic b light grey 0 18 0 20 0 510 0 811 0 44 0 34 black out OF 0 f metallic b light grey 0 18 0 20 0 285 0 807 0 04 0 68 half transparent OF 4 f metallic b white 0 50 0 15 0 160 0 830 0 06 0 74 half transparent OF 4 f
47. 6 Rendering options set for the ESve Radiance simulations performed for the experimental rooms of the Daylight Laboratory at SBi Figure 13 1 Measured and simulated daylight factors for the working plane in the reference room for Case1 The standard deviation is visible for each measurement Figure 13 2 Components of daylight a direct sun b direct sky c externally reflected and d internally reflected Figure 13 3 Measured and simulated daylight factors at the ceiling in the reference room for Case1 The standard deviation is visible for each measurement Figure 13 4 Measured and simulated daylight factors for the working plane in the test room for Case1 The standard deviation is visible for each measurement Figure 13 5 Measured and simulated daylight factors for the working plane for Case 1 for both reference and test room Figure 13 6 Measured and simulated daylight factors for the ceiling for Case 1 for both reference and test rooms Figure 13 7 Measurements and simulations at the working plane for the reference room for Case 2 Figure 13 8 Measurements at the working plane for both reference and test rooms for Case2 xii 63 64 64 64 65 66 67 67 68 68 70 72 74 75 76 77 78 79 79 79 Figure 13 9 Measurements and simulations at the working plane for the test room for Case2 Figure 13 10 Simulations at the working plane for both reference and test
48. 7 um MM 28057 38 Pikington Opttloat Green O 042 086 08 08 9 6 33 9 5 1 68 1540 33 258 8 3 Pilkington Suncoool Briliant 66 33 65 035 01 059 087 M 84346 94 05 0 85 1200 346 255 8 40 Pikington Suncool HP Silver 50 30 66 020 059 08 00 9 Mo 34 100 amp 9 7 98 3M 208 8 mt SSG Antelio Silver O 048 088 054 09 9 A 35 105 1 1 jt 1805 35 280 8 42 SSG Antelio Silver outer surface coated O 04 088 03 08 9 5 356 104 1 54 1764 35 BB 8 83 SSG Antelio Esmeralda O 0 28 057 048 068 90 258 399 1265 5 9 258 76 39 2016 9 44 SSG Antelio Esmeralda outer surface coated 96 o 055 0 amp 8 063 W 2609 48 26 4 9 269 705 403 198 9 45 SOG Reflectasol Green O 07 035 01 091 8 38 566 1H 0 9 38 397 56 2188 3 4 SSG Cool Lite KS147 6 026 053 099 057 9 415 42 HM 4 9 115 8600 412 018 8 Fo the systems that have orientable slats like venetian blinds and glass lamellas the properties refer to the system completely activated 90 slat position Te setpoint for cooling is 22 C so when the mechanical cooling is activated there are no hours above 22 C Toa energy demand heating demand 2 5 lightning demand Total energy demand heating demand cooling demand 25 lightning demand bo Table 6 3 Cont 2 Energy and indoor comfort performance of the landscaped office room in Copenhagen for the reference glazing and for the combination of the reference glazing with the different solar shading systems system properties without mechanical cooling with mechanical coo
49. 837 0000 reflectance transmittance indoor 5 solar 0 207 0 626 visual 0 292 0 658 uv 0 211 0 317 F single layer no coating etc M spectral properties as input AU I use properties for 0 30 and 60 degrees incidence angle use properties for substrate and for substrate film M use estimated values for angle dependent properties Input iG Output pane type 7 solar properties Return Import from text file f Freeze Select pane 566 ANTELIO SILVER sag v Record gg 2 PJPP of 462 Figure C 1 Specular pane window with SGG Antelio Silver pane active 3 Click on Calculate A window as the one in Figure C 2 will be presented mark the boxes Basics and Spectral and click on Create C 1 EE Detailed Output Patil sel Shire ue Figure C 2 Calculate window 3 A text file with the properties of the glass will be generated Copy to a new text file only the data organized in columns under the title Spectral Properties Total Solar four columns must be copied Wavel Transm Refl_o Refl_i wavelength varying from 300nm to 2500nm Save the new text file 4 Open the new text file in Microsoft Excel Follow the steps to assure that each value will be placed in a different cell Now that the spectral data from the glass pane is in Microsoft Excel it is easier to treat it in order to create the file for the glass lamellas 5 In the text file for the glass lamellas the columns with the spectral data m
50. GGReflectGreensIntLuxaflexVenBlind4078 H45 D2 54 SGGReflectGreen ExtAlumLamellas 60mm H45 F29 0 31 0 32 0 53 0 25 6 3 Results In Table 6 3 and Table 6 4 the performance of the landscaped office room is presented for the reference glazing and for the combination of the reference glazing with the different solar shading systems Table 6 3 refers to Copenhagen and Table 6 4 to Lisbon The results painted as grey are the ones that do not fulfil the standards The tables are organized in three distinct groups of columns System properties where the performances of the reference glazing and of the combination of different solar shading systems with the reference glazing are presented in terms of thermal transmittance coefficient U value solar heat gain coefficient g value solar shading coefficient SSC visual transmittance ty visual shading coefficient VSC and rendering index Ra These values were obtained in WIS and refer to the solar shading systems completely activated Without mechanical cooling the values presented in these columns were calculated in BuildingCalc LightCalc They show the performance of the landscaped office room previously described for the reference glazing and also for the combination of different solar shading systems with the reference glazing No mechanical cooling was set The performance of the office building with the different solar shading systems is presented in terms of energy d
51. INSTITUTO SUPERIOR TECNICO PERFORMANCE EVALUATION OF SOLAR SHADING SYSTEMS In s Dionisio Palma Santos Disserta o para obten o do Grau de Mestre em Engenharia Civil Orientadores estrangeiros Prof Svend Svendsen Prof Jacob Birck Laustsen Juri Presidente Prof Jorge Manuel Calico Lopes de Brito Orientador Prof Antonio Heleno Domingues Moret Rodrigues Vogal Prof Maria Helena Povoas Corvacho Outubro de 2007 Acknowledgements First would like to thank Professor Svend Svendsen and Research Assistant Jacob Birck Laustsen my supervisors at DTU during the months in which have been carrying out my master dissertation Thank you for all your support and great orientation would also like to thank Professor Ant nio Moret Rodrigues my supervisor at IST Thank you for supporting my idea of doing the master dissertation at DTU and for the support and comments when preparing the final version Special thanks to the PhD students Christian A Hviid and Steffen Petersen Christian thank you for all the support with BuildingCalc LightCalc and also with ESve Radiance thank you for your permanent availability Steffen thank you for helping me also with BuildingCalc LightCalc and for the support with the DUBLA worksheet Thank you also to Steen Traberg Borup from SBi Thank you for the daylight measurements data and for the visit to the Daylight Laboratory would also like to thank Jan Karolini from the IT gr
52. Total energy demand heating demand cooling demand 25 lightning demand In Figure 6 2 it is presented the solar shading coefficients for the different types of solar shading systems when compared to the reference glazing For the reference glazing the shading coefficient is equal to unit As expected the external shading systems have higher performance controlling the solar gains 1 00 0 90 E E 2 0 80 A gt 0 70 e S 0 60 e e Reference glazing g e Roller Blinds 8 0 50 Venetian Blinds 4 Glass Lamellas E 0 40 Solar Control Glass a gt 5 0 30 E 9 0 20 0 10 reference glazing internal interpane external 40 glass lamellas solar control glass type of solar shading system Figure 6 2 Solar shading coefficients for the different solar shading systems comparing to the reference glazing 6 4 Discussion of the Results 6 4 1 Copenhagen 6 4 1 1 The reference system Looking at the results for the energy performance of the landscaped office building in Copenhagen with the reference glazing it can be concluded that it is a relative high performance building The heating demand is extremely low 0 55 kWh m year for the case without mechanical cooling which is due to the very good thermal insulation of the building envelope very low U values 0 1W m K for exterior wall roof and ground and 0 68W m K for the window and also to the very high efficiency
53. ading systems may interfere with the concentration and efficiency levels of workers 7 1 1 Roller blinds For roller blinds the active position means that they are completely rolled down this is the way of blocking the direct sun during sunny days in order to reduce the solar gains through the window 7 1 2 Slat systems venetian blinds and glass lamellas For the slat systems venetian blinds and glass lamellas the daylight performance was evaluated for the cut off position which corresponds to open the slats as far as possible without letting the sunshine directly through the system see Figure 7 2 The cut off position depends on the actual position of the sun and for this reason the most critical situation for daylight is during winter time when the sun is lower In this case the cut off angle of the slats is higher which means that less daylight enters the room Due to different latitudes under the same circumstances same time and same slat shading system the cut off angle is higher for Copenhagen than for Lisbon Figure 7 2 Cut off position for a solar shading system composed of slats Figures a and b refer to different positions of the sun According to the sun path that can be printed using BuildingCalc LightCalc the lowest sun position occurs on December 21 day 355 It is around 12 00 o clock that the sun is normal to the facade solar azimuth angle y 0 At this time the solar altitude angle B is around 11
54. alc interface A 6 BuildingCalc LightCalc 2 3 7d 3 Luxaflex venetian blind 8 Perfora M a File Place Solar Geometry Building Indoor environment Simulation Settings BYG DTU Type of simulation Combined thermal and daylight BC LC Figure A 8 BuildingCalc LightCalc interface Advanced glazing and shading devices database Newentry Loaddatabase Save database Description g value dir o 0 0 0 0 0 g value dif o U value Wiri2K 0 r Thermal properties Shading position No shading z Visual transmittances tau Dir gt dir Dir diff Dir gt redir 0 0 0 o 0 0 o 0 0 0 o 0 Inner surface reflectance rho Slat distance Slat width 0 m 2 In the menu File click on Type of Project Choose Combined Simulation BC LC 3 Click on the option Glazings in the menu Building the window presented in Figure A 9 will be Greyed out boxes are not used in simulation Database r Project ERR m Figure A 9 Glazings window from Building menu A 7 3 Press the option New entry A window as the one in Figure A 10 will be displayed In the box Glazing and shading choose blinds as the shading device and choose Load data from For the clear glazing load the text file for the glazing without shading generated with WIS For the shading input load the 11 files 90 80 60 40 20 0 20 40 60
55. always above 26 C During these days the concentration and the efficiency of the workers would be reduced However only the yearly criteria will be checked since it is the one automatically calculated by BuildingCalc LightCalc Also in accordance with 14 for a category II building it is recommended that the PPD index is lower than 10 27 6 2 Characterization of the solar shading systems used In Table 6 2 it is presented the solar shading systems whose performances were evaluated in this dissertation as well as their geometrical thickness t thermal material conductivity material IR emissivity outdoor IR sou and material IR emissivity indoor IR ing and integrated optical characteristics solar transmittance ts solar reflectance ps visual transmittance ty and visual reflectance py Excluding the external venetian blinds aluminium lamellas and the glass lamellas the other solar shading systems were already in WIS database The external venetian blinds were modelled as presented in chapter 8 2 2 Venetian blinds of this dissertation and the glass lamellas as illustrated in APPENDICES C and D For the venetian blinds the letters w c and p define respectively the slat chord width the crown height and the slat pitch as shown in Figure 6 1 Nee ee oe fon NA ae iy co Figure 6 1 Venetian blind geometry 41 For the systems composed of slats as the venetian blinds and the glass lamellas the chara
56. an reduced it to 1 2 With external glass lamellas it is also possible to fulfil the standard indoor requirements without the use of mechanical cooling Once again if better levels of indoor environment are desired the mechanical system may be used In this case comparing to the solution with the reference glazing the total amount of energy demand can be reduced to between 1 2 and 2 3 depending on the type of glass that composes the glass lamellas As it was expected the electrical lightning demand is lower when using systems composed of slats than for instance roller blinds specially the ones with very low openness factors When the slat systems are activated to block the direct sun in order to avoid overheating the daylight can still 38 enter the room through the space between the slats The same does not happen with the roller blinds It would be expected that the electrical lightning demand of the office room when using glass lamellas systems was lower than the one when using for instance external venetian blinds However when comparing both electrical lightning demands they are very similar This is mainly due to the following difference between the two systems while the external venetian blinds can be completely retracted during overcast days the same does not happen with the glass lamellas they are permanenily in front of the fa ade and can only be tilted Concerning the solar control glasses not all the solutions simulated allo
57. angles around 90 may be too small to load properly Examine and use 85 89 if necessary Load module tested with WIS 3 0 1 Figure A 10 New entry window A 8 Appendix B How to add a new shading system to WIS It is possible to add new solar shading systems to the W S database This procedure may be done in two different ways 1 Inserting data manually 2 Importing a text file B 1 Inserting data manually This is the easiest way of defining a new solar shading system in the W S database 1 Open the Scattering layer window 2 Create a new record select the type of shading system and insert the following information Product information Geometry Thermal properties and Optical Properties The Optical properties can be set in two distinct ways as spectral data or as integrated data To input the spectral data a table as the one presented in Figure B 1 should be filled in for each wavelength the optical properties for the normal incidence angle should be defined The way to define the integrated data is different when comparing a roller blind with a slat shading system for a roller blind the integrated optical properties must be set for different incidence angles as shown in Figure B 2 while for a slat shading device only the optical properties for the normal angle of incidence must be set see Figure B 3 Shading spectral data ID 681 name no name specified specular scattering beam gt beam direc
58. ansparency 5 7 October 2003 11 Nielsen Toke Rammer Hviid Christian Anker BuildingCalc LightCalc Users guide BYG DTU 2006 87 12 Notes from Course 11116 Sustainable Buildings Powerpoint Presentation about Solar Shading Systems Department of Civil Engineering Technical University of Denmark Lyngby 2006 2007 2 semester 13 Petersen S ESVERadiance Notes from course 11120 2005 14 prENrev 15251 2006 E Indoor environment input for design and assessment of energy performance of buildings addressing indoor air quality thermal environment lightning and acoustics 15 Rayfront User Manual http www schorsch com rayfront manual August 2007 16 Regulamento das Caracter sticas de Coportamento T rmico dos Edif cios Colec o regulamentos 1 Porto Editora Porto 2006 17 Rosenfeld J L J WIS DATABASE Data Submission Procedure for Shading and Diffusing Components Version 1 0 Department of Civil Engineering Technical University of Denmark Lyngby May 2004 18 Skotte Tine Dagslysdirigerende solafskaermende glaslameller Polyteknisk Eksamensprojekt BYG DTU 2007 19 TRY Test Reference Year Meteorological National Institute and Civil Engineering National Laboratory Ano Clim tico de Refer ncia Lisbon December 1989 20 Wall Maria B low H be Helena Solar Protection in Buildings Report TABK 01 3060 Division of Energy and Building Design Department of Construction an
59. ar numa fase inicial de projecto O m todo baseia se na utiliza o de duas ferramentas WIS e BuildingCalc LightCalc Os sistemas de sombreamento solar integrados num edif cio podem ser automaticamente controlados e o seu desempenho energ tico e em termos de trasmiss o de luz natural pode ser avaliado Um caso estudo de um edif cio de escrit rios do tipo open space no qual diferentes sistemas de sombreamento solar foram testados apresentado Foram estudados dois climas distintos Copenhaga e Lisboa n tida a diferen a entre os dois climas assim como entre tipos distintos de sistemas de sombreamento solar Hoje em dia existe falta de informa o no que diz respeito s propriedades t micas e pticas de sistemas de sombreamento solar S o apresentados alguns exemplos e sugest es de como usar a informa o dispon vel Os resultados comparados com o uso de informa o completa mostram que a influ ncia no desempenho global do edif cio m nima No entanto poucos casos foram estudados e mais investiga o deve ser feita nesta rea Os sistemas de sombreamento solar compostos por lamelas de vidro s o solu es promissoras e exigem uma avalia o mais precisa no que diz respeito ao desempenho face transmiss o de luz natural para o interior dos edif cios Esta avalia o pode ser feita com recurso a ferramentas de raytracing Na Parte B desta disserta o medi es do n vel de ilumina o natural feitas no Laborat r
60. asurements and lESve Radiance simulations is similar For the lamellas tilted for Case 1 the daylight factor increases at the ceiling near the window while almost no influence is seen near the back wall see Figure 13 6 78 m REF Meas o REF IESve Rad 4 TEST Meas Daylight Factor E A TEST IESve Rad 0 0 1 0 2 0 4 0 5 0 6 0 Distance from the window m Figure 13 6 Measured and simulated daylight factors for the ceiling for Case 1 for both reference and 13 2 Case 2 test rooms Case 2 is similar to Case 1 only the orientation of the lamellas is different they are all tilted to the 30 position The relation between the measurements and ESve Radiance simulations is also similar to Case 1 and the comments made before are also valid for this case The results for Case 2 are only briefly presented for the working plane as graphs in Figures 13 7 13 8 13 9 and 13 10 m REF Meas REF IESve Rad 15 0 10 0 5 0 Daylight Factor 0 0 0 0 1 0 2 0 3 0 4 0 5 0 Distance from the window m Daylight Factor 4 TEST Meas a TEST IESve Rad 15 0 10 0 A 5 0 0 0 0 0 1 0 2 0 3 0 4 0 5 0 Distance from the window m 6 0 Figure 13 7 Measurements and simulations at the working plane for the re
61. be widened to more and more manufactures Regarding glazing it is easier to find spectral information available W S has a database for it and there is a database named Glassdbase 26 also with some information about it This last one is a database with data on commercial insulating glasses determined at the Institute of Physics at the University of Basel Switzerland and it is focused on sun protection glasses 12 3 Some useful definitions When characterizing and evaluating the performance of glazings and solar shading systems there are some standard terms usually referred by manufactures and designers These terms which will be used throughout this dissertation are next described 3 1 Electromagnetic spectrum The electromagnetic spectrum can be divided into wavelength intervals 1 A4 lt 380nm UV radiation this is the non visible ultraviolet radiation and it has a little meaning for the energy balance of buildings However this is the part of spectrum responsible for the long term colours change of buildings furniture It can be harmful for people 2 380nm lt A lt 780nm visible radiation this wavelength interval represents the visible light and it contains around 50 of the solar radiation It is important that windows have a high transmittance in this wavelength range to allow a high indoor daylight level 3 780nm lt A lt 2500nm near infrared radiation this part of the solar radiation is not visible and it represen
62. bon _type of solar shading system wimm pimm as 4 as 2 D Internal venetian blinds Valid for all D Interpane venetian blinds Valid for all F External venetian blinds 29 Aluminium lamellas 60mm 30 Aluminium lamellas_80mm 31 Aluminium lamellas_100mm G Glass lamellas Valid for all The relation between the slat width and the distance between two consecutive slats has an important influence on the cut off angle This is the reason for such different cut off angles when comparing different slats systems 7 1 3 Reference glazing and solar control glazings For the reference glazing and solar control glazings studied there is no active or non active position These systems are not flexible to different sky conditions Thus the daylight factor at point A should be 5 in order to avoid the use of electrical lightning during the most critical situation for daylight the overcast days 7 2 Results In Table 7 2 the daylight factor calculated with LightCalc is presented for the reference glazing and for the different solar shading solutions The values refer to point A As stated before the roller blinds are completely activated while the slats systems venetian blinds and glass lamellas are in the cut off position For the slats systems there are two different values that correspond to distinct cut off positions for Copenhagen and Lisbon 44 Table 7 2 Daylight factors calculated in point A x 10m y 8m z 0 85m with
63. cond is 1 0m offset from the first one The top of the tables is 0 85m offset from the floor The reflectance of the tables is 80 see Figure 11 4 1 325 m 3 50 m 0 75 m 1 325 m 0 64m 1 50m 1 00 m 1 50m 1 36 M smn Figure 11 4 Position of the tables inside the experimental rooms 11 1 6 The glass lamellas system As it was stated before the only difference between both experimental rooms is that one of them named the Test room throughout this dissertation is equipped with a glass lamellas system on the exterior side of its fagade while the other named the Reference room does not have the glass lamellas system mounted on its fa ade The purpose of the measurements was to evaluate the influence of the glass lamellas shading system on the daylight level inside the rooms The glass lamellas system is composed of five glass lamellas which are supported by horizontal metallic profiles along their length The horizontal metallic profiles are supported on their extremes by two vertical lateral profiles see Figure 11 5 The horizontal profiles can move up and down along the vertical profiles and they are able to rotate so the orientation of the lamellas can be changed For the measurements the axis of rotation of the lower lamella was set 0 9m offset from the floor of the room and approximately 0 30m from the glazing The distance between two consecutive lamellas is 0 5m Each lamella
64. cteristics refer to the system completely activated slat angle of 90 28 6z SONDA RONAD ae o 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Table 6 2 Properties of the solar shading systems whose performances were evaluated Internal Roller Blinds Verosol Roller 818 000 UT light grey Verosol Roller 818 741 UT beige Verosol Roller 818 936 UT dark grey Verosol Roller 875 000 BO light grey Verosol Roller 875 936 BO dark grey Verosol Roller 816 000 T light grey Verosol Roller 816 936 T dark grey Verosol Roller 312 000 HT dark grey Verosol Roller 312 936 HT dark grey Verosol SilverScreen white EDO1 HT Verosol SilverScreen black EBO1 HT Interpane Roller Blinds Verosol Roller 818 000 UT light grey Verosol Roller 875 000 BO light grey Verosol SilverScreen white EDO1 HT Verosol SilverScreen black EBO1 HT External Roller Blinds Verosol SilverScreen white EDO1 HT Verosol SilverScreen black EBO1 HT Internal Venetian Blinds Luxaflex venetian blind 8 Perforation 2053 Luxaflex venetian blind 8 Perforation 6127 Luxaflex venetian blind 8027 Luxaflex venetian blind High Mirror 4078 Luxaflex venetian blind Metallic 8081 Luxaflex venetian blind Thermostop 2383 Interpane Venetian Blinds Luxaflex venetian blind 8 Perfor 2053 Luxaflex venetian blind 8 Perfor 6127 Luxaflex venetian blind 8027 Luxaflex venetian blind High Mirror 4078 Luxaflex venetian blind Thermostop 238
65. d Architecture Lund Institute of Technology Lund University 2001 21 Wall Maria B low H be Helena Solar Protection in Buildings Part2 2000 2002 Report TABK 01 3060 Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University 2003 22 Ward Larsson G Shakespeare R Rendering with Radiance The Art and Science of Lighting Vizualization Morgan Kaufmann Publishers San Francisco CA 1998 88 Sources from the Internet 23 http www1 hunterdouglascontract com May 2007 24 http www coltinfo co uk May 2007 25 http www en sbi dk research August 2007 26 http www glassonweb com July 2007 27 http www glassdbase unibas ch May 2007 28 http www luxaflex com uk May 2007 29 http www passiv de April 2007 30 http www pellini net August 2007 31 http www radiance online org June 2007 32 http www schorsch com rayfront manual matdef html July 2007 33 http www sciencedirect com Renewable Energy Volume 23 Issues 3 4 July 2001 Pages 497 507 34 http www velux com May 2007 35 http www verosol com July 2007 36 http www warema de July 2007 89 Software 37 BSim 2002 Danish Building and Urban Research Model of the Daylight Laboratory at SBi http www bsim dk 38 BuildingCalc LightCalc version 2 3 1f BYG DTU Technical University of Denmark 2007
66. d respectively to 200lux and 500lux during an overcast situation in which the global illuminance is commonly 10000lux The daylight factor was calculated in one specific point of the room point A x 10m y 8m z 0 85m see Figure 7 1 This point is centred according to the fagade and it is 0 85m offset from the floor working plane and 2m offset from the back wall It was assumed that no working areas will be set after this point when looking from the window 10 Y axes 0 2 4 6 8 10 1g 14 16 18 20 X axes Figure 7 1 LightCalc picture of the room showing point A x 10m y 8m z 0 85m where the daylight factor was determined for each solution of solar shading system combined with the reference glazing Different colours represent different levels of daylight factor 41 The daylight factor for the different solar shading systems was calculated for the active position in order to avoid the use of electrical lightning during an overcast sky the daylight factor should be around 5 in point A This could seem a contrasense at first glance since the typical situation is that the shading systems are removed during overcast skies The idea was to simulate the days in which the sky is constantly changing from sunny to overcast and vice versa In real situations it is not good to be constantly changing the position of the solar shading systems according to the sky conditions Even if the control is automatic the frequent movements of the sh
67. dark grey 0 54 0 27 0 55 0 01 0 01 93 0 44 8 74 22 27 131 10 0 44 14 98 8 06 35 57 8 6 Verosol Roller 816 000 T light grey 0 59 0 36 0 73 0 23 0 34 94 0 48 4 58 11 93 162 10 0 50 16 50 4 32 27 78 8 7 Verosol Roller 816 936 T dark grey 0 59 0 36 0 73 0 21 0 31 95 0 48 4 60 11 98 162 10 0 50 16 50 4 33 27 82 8 8 Verosol Roller 312 000 HT dark grey 0 55 0 28 0 57 0 04 0 06 95 0 45 8 20 20 95 133 10 0 46 14 94 7 45 34 02 8 9 Verosol Roller 312 936 HT dark grey 0 55 0 28 0 57 0 02 0 03 94 0 45 8 24 21 05 134 10 0 46 15 05 7 61 34 52 8 10 Verosol SilverScreen white ED01 HT 0 51 0 25 0 51 0 05 0 07 94 0 41 7 15 18 27 101 9 0 41 12 47 6 69 29 59 8 11 Verosol SilverScreen black EBO1 HT 0 51 0 25 0 51 0 04 0 06 94 0 41 7 28 18 61 101 9 0 41 12 38 6 82 29 83 8 B Interpane Roller Blinds 12 Verosol Roller 818 000 UT light grey 0 72 0 30 0 61 0 32 0 47 95 0 65 3 71 9 93 103 9 0 66 12 28 3 61 21 94 8 13 Verosol Roller 875 000 BO light grey 0 71 0 11 0 22 0 03 0 04 94 0 79 7 92 20 59 17 8 0 79 6 38 7 61 26 19 8 14 Verosol SilverScreen white ED01 HT 0 70 0 10 0 20 0 05 0 07 94 0 80 6 63 17 38 2 8 0 80 5 40 6 41 22 21 8 15 Verosol SilverScreen black EBO1 HT 0 70 0 10 0 20 0 04 0 06 95 0 81 6 68 17 51 0 8 0 81 5 11 6 44 22 02 8 Cc External Roller Blinds 16 Verosol SilverScreen white ED01 HT 0 62 0 04 0 08 0 01 0 01 94 0 77 6 33 16 58 0 8 0 77 3 24 6 18 19 46 8 17 Verosol SilverScreen black EB01 HT 0 62 0 03 0 06 0 03 0 04 95 0 78 6 31 16 56 0 8 0 78 2 97 6 17 19 18 8 D Internal V
68. different solar shading systems applied on the fagade of the office ste Daylight factor in point Position Type Product name A x 10m y 8m z 0 85 Copenhagen Reference Glazing 2 5 A Internal Roller Blinds 1 Verosol Roller 818 000 UT light grey 1 2 4 Verosol Roller 875 000 BO light grey 0 1 10 Verosol SilverScreen white EDO1 HT 0 2 B Interpane Roller Blinds 12 Verosol Roller 818 000 UT light grey 1 2 13 Verosol Roller 875 000 BO light grey 0 1 14 Verosol SilverScreen white EDO1 HT 0 2 Cc External Roller Blinds 16 Verosol SilverScreen white EDO1 HT 0 2 D Internal Venetian Blinds cut off angle CPH 41 LIS 18 18 Luxaflex venetian blind 8 Perforation 2053 0 4 1 0 19 Luxaflex venetian blind 8 Perforation 6127 0 2 0 7 20 Luxaflex venetian blind 8027 0 5 1 1 21 Luxaflex venetian blind High Mirror 4078 0 4 1 1 E Interpane Venetian Blinds cut off angle CPH 41 LIS 18 24 Luxaflex venetian blind 8 Perfor 2053 0 3 1 0 25 Luxaflex venetian blind 8 Perfor 6127 0 3 0 8 27 Luxaflex venetian blind High Mirror 4078 0 4 1 1 28 Luxaflex venetian blind Thermostop 2383 0 4 1 1 F External Venetian Blinds 29 Aluminium lamellas 60mm cut off angle CPH 47 LIS 23 0 1 0 5 30 Aluminium lamellas_80mm cut off angle CPH 51 LIS 26 0 2 0 7 31 Aluminium lamellas 100mm cut off angle CPH 53 LIS 28 0 2 0 7 G External Glass Lamellas cut off angle CPH 68 LIS 35 32 SGG_Ant
69. ding code the maximum value for primary energy consumption for new office buildings is 35kgep m year This means a maximum of 121kWh m year considering that all the energy in the building comes from electricity which is the most critical case for electricity 0 290kgep kWh 16 While the Danish building code 2 defines only a limit for the total energy consumption of the building allowing the designer to save energy in different fields the Portuguese code 16 defines also limits for the different types of energy needed in a building According to 16 Portugal is divided in different climatic zones and these limits depend on the location of the office building and 1 2871h is an output of BuildingCalc LightCalc and it corresponds to 11 hours per day 5 days per week during one whole year It was assumed that the ventilation systems would be switched on one hour before the working hours and switched off one hour after the working hours No holidays were assumed 26 on its shape factor FF which is the ratio between the exterior envelopment of the building and the inner volume For the studied building which has a shape form of 0 30 located in Lisbon which corresponds to winter climatic zone 1 and summer climatic zone V2 south the maximum values for the different energy demands are presented in Table 6 1 Table 6 1 Maximum values for energy consumption calculated according to the Portuguese building code 16 Consumption Limit
70. ditions is based on a simple thermal model of the room The building envelope is simply defined by an overall UA value that takes into account the sum of the thermal transmission losses through the fagade excluding the window The losses through the window are characterized separately The heat capacity of the construction and the internal surface area are also defined 17 It is possible to set different systems heating cooling ventilation with air variable volume and heat recovery venting and variable solar shading The solar shading is the main focus of this dissertation The systems are controlled by different settings which can be specified for different periods This means that different control settings can be defined for summer and winter time and for working hours and non working hours It is possible to plot and export the results from the simulations in an hourly basis The location and weather data need also to be set The LightCalc component based on the radiosity method is able to estimate daylight levels in a room under different sky conditions BuildingCalc LightCalc results from the combination of the features of BuildingCalc with LightCalec In this way the daylight levels will be estimated taking into account the shading control and consequently this will have an influence on the electrical lightning demand Also the extra heat gain from the electrical lightning is taken into account 11 In APPENDICES A B C and D
71. e component in reality there is also a diffuse component The different numbers of hours of overheating obtained when mechanical cooling is not used for the use of complete data and simplified data can be partly explained by the difference on the electrical lightning demand If the electrical lightning demand is lower lower are the internal loads and less are the hours of overheating However the g value of the glazing combined with the shading also has an influence higher the g value is lower should be the number of hours of overheating The use of integrated data instead of spectral data can be the reason for different g values 52 For the internal venetian blind simulated there was a decrease of 40 hours above 26 C when using simplified data It would be expected the opposite as the g value is higher for the simplified case No reason was found for this The results obtained for the last case study Warema aluminium lamellas 60mm Raffstoren 94 A6 RAL 9006 can not be compared since there is no available data characterizing this system in WIS Apparently the results show that simplified data can be used when evaluating the energy performance of solar shading systems the results obtained for the energy performance of the building using simplified data are quite close to the ones when using complete data However only few cases were studied more detailed studies should be done in this field and for different types of solar shading
72. e Daylight Laboratory at SBi Figure 11 3 Landscape view from the Reference room of the Daylight Laboratory at SBi Figure 11 4 Position of the tables inside the experimental rooms Figure 11 5 Picture of the glass lamellas system mounted on the fa ade of the Test room Figure 11 6 Real section of the horizontal metallic profiles in which the glass lamellas are supported xi 10 10 11 20 28 37 41 42 43 43 60 60 61 62 63 63 Figure 11 7 Section of the horizontal metallic profiles in which the glass lamellas are supported as they were modelled in ESve Figure 11 8 Plan of the Test room Reference room with the location of the measuring points Figure 11 9 Section of the Test room Reference room with the location of the measuring points Figure 11 10 Case studies sky conditions and position of the glass lamellas for the Test room Figure 11 11 Overcast factor for the measurements performed for Case 1 Figure 11 12 Overcast factor for the measurements performed for Case 2 Figure 12 1 Raytracing method used in Radiance Figure 12 2 Model of the experimental rooms built in ESve Figure 12 3 Interior of the experimental rooms modelled in ESve Figure 12 4 Image of the model in ESve showing the auxiliary cylinders created in the measuring points positions Figure 12 5 Diagram of how Radiance simulations handle the encountering of a surface of a trans material Figure 12
73. e and reflected on the surfaces until they intersect a light source or until the ray has reflected more than a specified number Figure 12 1 Raytracing method used in Radiance 22 12 2 Settings and assumptions 12 2 1 The model The model of the experimental rooms was built in ESve according to the description previously made of the experimental rooms see Figure 12 2 and Figure 12 3 The landscape was simply modelled as a field of grass with a length of 20m the distant row of trees towards south and the group of trees towards the south west direction were neglected The model of the test room for the different Cases 1 2 3 and 4 is presented in APPENDIX F i Experimental room Gangway 7m Figure 12 2 Model of the experimental rooms built in ESve 67 Glass Lamellas Figure 12 3 Interior of the experimental rooms modelled in ESve Auxiliary solids located in the measuring points were created to make possible the reading of the illuminance and daylight factor levels in the images generated by ESve Radiance These auxiliary solids are cylinders with a diameter of 0 04m and a height of 0 02m and they are represented in Figure 12 4 The reflectance of the measuring points was assumed to be 80 the same reflectance of the tables Figure 12 4 Image of the model in ESve showing the auxiliary cylinders created in the measuring points positions 12 2 2 The surfaces properties In Radiance ther
74. e are different types of materials according to the way the surfaces perform when exposed to light plastic metal glass dielectric and trans 13 Excluding the windows glazings which were defined as glass and the glass lamellas which were defined as trans all the other surfaces in the model were defined as plastic 12 2 2 1 Plastic Material All surfaces excluding glazings and glass lamellas In Radiance plastic defines opaque surfaces with uncoloured specular highlights This type of material is defined by its red green and blue RGB reflectance values and a value for specularity and roughness The reflectance values vary between 0 0 and 1 0 0 0 0 0 0 0 defines a black surface while 1 0 1 0 1 0 defines a white surface The specularity is the amount of light reflected by specular mirror like not diffuse mechanism Specularity also varies from 0 0 to 1 0 0 0 defines a perfectly diffuse surface while 1 0 a perfect mirror For plastic materials the specularity is usually in the range 0 0 0 07 The roughness refers to how the surface scatters the light that is reflected 0 0 corresponds to a perfectly smooth surface and 68 a 1 0 would be a very rough surface Roughness values above 0 2 are unusual The roughness affects only the specular reflection In Table 12 1 the RGB reflectances specularity and roughness for the surfaces modelled as plastic material are presented All the surfaces excluding the tables whose appearance is slig
75. e pane including multiple reflections The visual transmittance value is the one given by manufactures which is 72 for the double pane glazing of the experimental rooms The visual transmittance is converted in transmissivity through the following formula ma J 0 8402528435 0 0072522239 Tn 0 9166530661 0 003626119 Tn 12 1 where Tn represents the transmittance and tn the transmissivity For the glazing of the windows of the experimental rooms the transmissivity is then 0 62 All the components R G and B are equal to 0 62 since the glazing is clear 69 Table 12 2 RGB transmissivities of the glazings of the experimental rooms Element R tn G tn B tn Glazings 0 62 0 62 0 62 12 2 2 3 Trans Material Glass Lamellas According to 13 the glass lamellas were modelled as trans material Trans represents a transparent translucent material type The trans materials are defined in Radiance by seven parameters R reflectance G reflectance B reflectance specularity roughness transmissivity and transmitted specularity The way how Radiance handles the encountering of a surface of a trans material is described in Figure 12 5 light input f C 18 specular reflection A 1 0 spec M rest 1 1 0 spec x absorbtion heat lt color n N 1 0 spec 1 0 color colored light R 1 0 spec color SS u Sy diffuse reflection o 1 0 spec color 1 0 trans
76. ed data and no spectral data In this way it is more difficult for the designer to access the performance of the solar shading systems In this chapter some tips on how to make use of the data usually given by the manufactures will be suggested for W S and BuildingCalc LightCalc simulations Also some examples will be illustrated and the results compared with the ones obtained with the use of complete data 8 1 General Assumptions Often the shadings properties that are required in WIS to characterize a shading system are not given by the manufactures For instance some of the WIS inputs are the thermal conductivity outdoor and indoor IR emissivities and IR transmissivity of the material that composes the shading system and usually manufactures do not have available this information Regarding optical data manufactures only give simplified information as the solar transmittance ts solar reflectance ps light transmittance ty and light reflectance py These values represent integrated data and include direct and diffuse components which should be set separately in WIS In Table 8 1 some tips are suggested of how to input new solar shadings systems in W S when the complete technical information is not available the tips are organized according to the different WIS input fields geometry thermal properties and optical properties Table 8 1 Tips on how to use simplified data from manufactures WIS input field Properties Tip
77. el shape the diffuse component is higher while through wide and short holes the direct component is higher More studies should be done regarding this subject Assume that the optical properties are equal for the outside and inside surfaces If no information about the UV transmittance tuv and UV reflectance puv is given by the manufacture assume that they are equal to the solar transmittance ts and solar reflectance ps Venetian blinds Integrated data solar visual and UV for transmittance and for outdoor and indoor reflectance for normal angle of incidence the values must be separated into direct and diffuse components Venetian Blinds Assume that all of the transmittance is direct and that all of the reflectance in diffuse see comments above for the same assumption for the roller blinds Assume that the optical properties are equal for the outside and inside surfaces If no information about the UV transmittance tuv and UV reflectance puv is given by the manufacture assume that they are equal to the solar transmittance ts and solar reflectance ps These suggestions are in accordance with typical solar shading systems available in the WIS database 48 8 2 Case studies In this chapter simulations for some solar shading systems studied before were performed but using the data usually given by the manufactures and doing the assumptions above proposed For the simulation
78. electrical lightning demand during overcast days However the design tools used in this dissertation W S and BuildingCalc LightCalc are not able to evaluate their performance For the roller blinds the daylight factor in point A is very low for instance 0 1 and 0 2 for black out and half transparent blinds respectively This means that if they are activated for a sunny day and if it turns into overcast and they are not retracted high electrical lightning demand may be needed to fulfil the requirements for indoor lightning level In this way the roller blind does not seem the best solution when thinking about avoiding the adjustments of shading systems that may disturb the workers concentration and efficiency For the venetian blinds different daylight performances for Copenhagen and Lisbon can be achieved because of the different cut off positions comparing both cities Because of different latitudes the solar altitude in Copenhagen is lower than in Lisbon In this way comparing Copenhagen with Lisbon for the same venetian blind for Copenhagen the cut off position angle is higher which means that less daylight enters the room This is the reason for the lower values obtained for the daylight factor in the office building in Copenhagen when compared to the office in Lisbon The values achieved for the daylight factor between 0 1 and 0 5 for Copenhagen and 0 5 and 1 1 for Lisbon are better than the ones obtained with the roller blinds espec
79. elio Silver_500mm 1 7 1 8 33 SGG_Antelio Clear_500mm 1 1 1 3 34 SGG_Reflectasol Grey_500mm 0 5 0 9 35 Glav_Stopsol Silverlight Green_500mm 0 6 0 7 H Solar Control Glazings 36 Pilkington Artic Blue 1 9 40 Pilkington Suncool HP Silver 50 30 1 6 41 SSG Antelio Silver 2 0 43 SSG Antelio Esmeralda 1 6 45 SSG Reflectasol Green 0 8 46 SSG Cool Lite KS147 1 5 7 3 Discussion of the results The results show that using the reference glazing the daylight factor in point A is 2 5 This value corresponds to an illuminance of 250 lux during an overcast sky which is enough for general light level in office buildings but not when performing tasks 500lux is the requirement This indicates that electrical light must be switched on when performing tasks during overcast skies For the solar control glazings the daylight factors in point A vary between 0 8 and 2 0 In this case electrical lightning may be needed during overcast days not only when performing tasks but also to keep the required general light level in the office This situation could be improved using solar control glasses whose optical properties vary according to the sky conditions these glasses become darker under sunny skies avoiding the solar gains to enter the room also the light transmittance decreases in this case on the other hand 45 under overcast skies the glass becomes clear again and the light transmittance increases These types of glass could decrease the
80. emand for heating and lightning total energy demand hours of overheating and PPD index With mechanical cooling these columns also refer to the performance of the office room with the different solutions for the solar shading systems in combination with the reference glazing In this case mechanical cooling was applied to eliminate completely the hours of overheating and the energy demand for it is also presented as 22 C is the setpoint defined for cooling no hours above this temperature will be registered Notes The simulations for Denmark were done using a version of BuildingCalc LightCalc that had an error Venting during night and weekends was only occurring when the outdoor temperature was lower than the cooling setpoint even if the indoor temperature was higher than the outdoor temperature This could lead to more hours of overheating than in a real situation However the influence of this mistake was tested in the updated version of BuildingCalc LightCalc and for most cases only a reduction of approximately 10hours above 26 C was detected This difference is insignificant and does not have an important influence on the cooling demand for the building when mechanical cooling is activated For Portugal the updated version of BuildingCalc LightCalc was used While for Portugal the hours of overheating above 22 C 24 C and 26 C are presented for Denmark only hours above 26 C are presented The reason is that the simulations for Den
81. ence outer pane H Solar Control Glazings when there is a coated surface if nothing else is referred it means that the coated surface is facing the air cavity 36 Pilkington Artic Bue body tinted float glass 4 7 0837 049 37 Pikingion Optioat Clear body tinted float glass 4 837 087 og 38 Pilkington Optifloat Green body tinted float glass 4 837 837 56 39 Pilkington Suncoool Brilliant 66 33 soft low e coating high visible light transmittance 4 837 030 39 40 Pilkington Suncool HP Silver 50 30 soft lowe coating high visible light transmittance 6 8370084 09 41 SSG Antelio Silver hard coating applied on a clear glass 6 837 0897 3 42 SSG Antelio Silver outer surface coated hard coating applied on a clear glass 6 837 0897 3 43 SSG Antelio Esmeralda hard coating applied on a body tinted glass 6 837 0897 50 44 SSG Antelio Esmeralda outer surface coated hard coating applied on a body tinted glass 6 837 0897 50 45 SG Reflectasol Green hard coating 6 837 0897 19 4 SSG Cool Lite KS147 soft coating 6 837 006 29 Combinations combination of the previous solutions 47 PilkingArticBluesIntVerosolSilverScreenEDO1 H36 A 48 PilkingArtic BluerExtVerosolSilverScreenEDO1 H36 C16 49 PilkingArticBlue nt LuxaflexVenBlind4078 H36 D2 50 PilkingArticBlue ExtAlumLamellas_60mm H36 F29 these solutions result from combinations of the previous ones 51 SGGReflectGreensIntVerosolRolerEDO H45 A 52 GGRellectGreen ExtVerosolRoller EDO H45 C16 53 S
82. enetian Blinds 18 Luxaflex venetian blind 8 Perforation 2053 0 58 0 36 0 73 0 04 0 06 95 0 43 4 54 11 78 229 12 0 47 20 85 4 30 32 07 7 19 Luxaflex venetian blind 8 Perforation 6127 0 58 0 44 0 90 0 04 0 06 96 0 42 4 64 12 01 252 12 0 47 22 37 4 34 33 68 7 20 Luxaflex venetian blind 8027 0 60 0 30 0 61 0 00 0 00 78 0 46 4 51 11 72 217 12 0 50 20 06 4 29 31 27 F 21 Luxaflex venetian blind High Mirror 4078 0 58 0 23 0 47 0 00 0 00 90 0 46 4 51 11 72 214 12 0 49 19 79 4 30 31 02 VA 22 Luxaflex venetian blind Metallic 8081 0 54 0 27 0 55 0 00 0 00 94 0 39 4 49 11 62 213 11 0 42 19 72 4 28 30 83 7 23 Luxaflex venetian blind Thermostop 2383 0 56 0 24 0 49 0 00 0 00 83 0 42 4 49 11 63 207 11 0 45 19 48 4 28 30 61 7 For the systems that have orientable slats like venetian blinds and glass lamellas the properties refer to the system completely activated 90 slat position 2 The setpoint for cooling is 22 C so when the mechanical cooling is activated there are no hours above 22 C 3 Total energy demand heating demand 2 5 lightning demand Total energy demand heating demand cooling demand 2 5 lightning demand oo Table 6 3 Cont 1 Energy and indoor comfort performance of the landscaped office room in Copenhagen for the reference glazing and for the combination of the reference glazing with the different solar shading systems system properties without mechanical cooling with mechanical cooling value gwae SSC 1 VSC Ra heating lightning t
83. ent solar shading systems were tested is presented The building was studied for two different climates Copenhagen and Lisbon It is clear the difference when comparing different solar shading systems and different climates Nowadays there is still a lack of information about the thermal optical properties of solar shading systems Some examples and suggestions of how to use the simplified data available are presented The results compared with the use of complete data show that the difference on the final performance of the building is not significant However more research should be done in this field as only few cases were studied The glass lamellas are a promising type of solar shading system that demands for more precise daylight evaluation using raytracing tools In Part B of this dissertation daylight measurements for glass lamellas systems performed in the experimental rooms of the Daylight Laboratory at SBi Danish Building Research Institute were compared with ESve Radiance simulations Results show that ESve Radiance may be used to evaluate the daylight performance of glass lamellas systems in most situations Keywords Solar shading systems office buildings energy daylight glass lamellas WIS BuildingCalc LightCalc IESve Radiance Resumo Esta disserta o composta por duas partes Parte A e Parte B Na Parte A apresentado um m todo simples de como avaliar o desempenho de diferentes sistemas de sombreamento sol
84. ery high energy consumption for cooling A solar shading system main goal is to reduce the need for cooling avoiding the solar gains to get into the building At the same time the shading systems can control the daylight in buildings avoiding glare problems If completely activated outside the working hours they improve the U value of the window system decreasing the heat exchanges between the inside and outside of the building 5 1 Settings for Copenhagen The test room will be a storey of a landscaped office building with a rectangular form located in Copenhagen North Europe Also a study of the same building but located in Lisbon South Europe will be done Next the characteristics for the building located in Copenhagen are presented The building in Lisbon has almost the same properties apart from some changes later presented The main goal is that the building is a relative high performance one according to energy and indoor comfort points of view According to energy it should fulfil the energy frame for Denmark and Portugal Regarding indoor comfort 14 the building should fulfil Category Il which means Normal level of expectation 5 1 1 General information and dimensions The building will have only one fagade and it will be facing south The rest of the boundary walls will be in contact with heated spaces It was assumed that near the front fagade there are no other buildings elements that could in someway originate shades
85. esearch Delft The Netherlands November 2003 4 Dubois Marie Claude mpact of Solar Shading Devices on Daylight Quality Measurements in Experimental Office Rooms Report TABK 01 3061 Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University 2001 5 Dubois Marie Claude Impact of Solar Shading Devices on Daylight Quality Simulations with Radiance Report TABK 01 3062 Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University 2001 6 Dubois Marie Claude Solar Protective Glazing for Cold Climates A parametric Study of the Energy Use in Offices Department of Building Science Lund Institute of Technology Lund University 1998 7 Dubois Marie Claude Solar shading for Low Energy Use and Daylight Quality in Offices Simulations Measurements and Design Tools Report TABK 01 1023 Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University 2001 8 Information given by Steen Traberg Borup at Daylight Laboratory at SBi via e mail 9 Jensen Jerry Moller Lund Hans Design Reference Year Dry Et Nyt Dansk Referencear Meddelelse Nr 281 Laboratoriet for varmeisolering Danmarks Tekniske Universitet Oktober 1995 10 Kuhn Tilmann E Kuhn Summary of the lecture at the Conference on Tall Buildings and Tr
86. ess the demand for electrical lightning is The drawback of windows is that the heat losses and the solar heat gains occur mainly through them If they are not carefully designed they can largely influence the building energy demand for heating and cooling To avoid the heat losses the windows must have a low thermal transmittance coefficient while solar shading systems must be applied to decrease the unwanted solar gains The solar shading systems are the central part of this dissertation If they are not correctly used they can have no positive effect or even a negative effect on the overall performance of buildings First of all the solar shading systems must be flexible to different exterior conditions They need to be activated especially during warm and sunny days to block the solar gains and consequently avoid the overheating On the other hand during cold and sunny days it should be possible to retract them in order to allow the solar gains to enter the building reducing in this way the heating demand Another problem is often associated with the use of solar shading systems when activated to block the sun rays and avoid the solar heat gains and overheating the solar shading systems also block the light In this way the need for electrical lightning increases The critical point is when the increase on electrical lightning demand is higher than the decrease on cooling demand caused by the use of the solar shading system In this situation
87. etpoint of 26 C for a cloth level of 0 5 but 22 C will be set even if the cloth level needs to be higher The objective is that the cooling will start before the indoor temperature reaches 26 C This is a way of decreasing the hours of overheating above 26 C which is ameasure of discomfort Only during working hours mechanical ventilation is active with an airchange rate of 0 9h which corresponds to 0 8I s m requirement for a category Il very low polluted landscaped office 14 22 During working hours no venting was set This is to contemplate the fact that sometimes office buildings are placed in areas with noise In this way venting by opening windows can lead to high levels of noise inside the office which can interfere with workers concentration and efficiency Thus the indoor air quality should be guaranteed without venting Outside the coldest months venting with a setpoint of 20 C was set at night and during weekends This is especially important during summer nights to cool down the office when the outdoor temperature is lower The internal loads during the working hours were assumed to be 100W per person and 50W per equipment which gives a total of 2250W considering the 15 working places The shading system will be dynamically controlled It will be automatically activated when the indoor temperature is higher than the cooling setpoint According to the needs different positions can be set for the shading system For i
88. evel in the working plane and leads to major overheating and heating losses The most efficient solution for indoor daylight is to place the window as high as possible The reference glazing will be a triple pane one with a total thickness of 39 55mm The outer panes will have low e coatings on the internal surfaces The inner pane will be a clear one The gaps will be filled with 90 of argon and 10 of air The different components of the glazing come from WIS software and are presented in Table 5 1 The properties of the glazing are shown in Table 5 2 20 Table 5 1 Composition of the reference glazing for the test room fagade Optitherm SN 4 UC Air Argon 10 90 clear_04 gvb UU Air Argon 10 90 Optitherm SN 4 the letters U and C mean Uncoated surface and Coated surface respectively the first letter refers to the outer surface of the glass pane and the second to the inner one Table 5 2 Properties of the reference glazing for the test room fa ade U value W m k g value Ty Ra Yo The frame used is FWT 50 1 HA E Plus a certificate product from 29 As in BuildingCalc LighCalc it is not possible to simulate the mullions the properties of an equivalent frame placed only in the border of the window have to be calculated These equivalent properties are presented in Table 5 3 Table 5 3 Properties of the equivalent frame for the test room fagade propert U value W m K 0 73 Frame width m 0 08 Linear
89. ex Venetian Blind 8 Perforation 2344 Slat shading device Luxaflex Venetian Blind 8 Perforation 6127 Luxaflex Venetian Blind 8 Perforation 6127 Slat shading device M This object is FROZEN and cannot be editted or un frozen Product into Geometry Thermal properties Optical properties thickness 0 22 slat chord width w 25 crown height c 2 mm Os ond a we slat pitch p 20 mm we slat angle 90 degrees cow Slat orientation Horizontal C Vertical Go to sei Return Output Calculate Import from text file Record aog 6 PJPH of 339 Figure A 5 Scattering layer window Luxaflex 8 Perforation 2053 record is activated 14 Open one by one the text files you created for the different slats angles In these text files there is a part that seems like a large table where the properties presented are dependent on the incidence angle Check if these values are well organized in columns If not round up the numbers to a maximum of 6 digits in order to arrange them back in columns If this is not done BuildingCalc LightCalc is not able to read the text files See Figure A 6 and Figure A 7 15 Now the text files with the properties of the glazing without shading and with shading for different slats angle positions are ready to be used in BuildingCalc LightCalc A 5 prop o 10 20 30 40 abs 1 0 262 0 263 0 264 0 266 0 268 abs 2 0 000 0 000 0 000 0 000 0 000 abs 3 0 130 0 130 0 130 0
90. factor DL factor at the working plane height 0 85m are presented for the test room room with glass lamellas for Case 1 76 Table 13 5 Daylight factors at the working plane for the test room for Case 1 measurements and lIESve Radiance simulations window m E Dom o DL factor Stdev DL factor Diference 122 336 103 156 Figure 13 4 shows once again the results from ESve Radiance simulations are inside the range defined by the measurements and correspondent standard deviations 25 0 20 0 xz S 15 0 Q A TEST Meas Ww A TEST IESve Rad gt 10 0 2 a 5 0 0 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 4 Measured and simulated daylight factors for the working plane in the test room for Case1 The standard deviation is visible for each measurement Table 13 5 and Figure 13 4 show that for the test room the daylight factors obtained with lESve Radiance simulations are lower than the measurements This would be expected since the daylight factors for the reference room were already lower for simulations than for the measurements The important thing is that the performance of the glass lamellas is similar when comparing measurements with ESve Radiance simulations Both for the measurements and simulations the glass lamellas decreased the daylight factor at the working plane close to the window Also for both
91. factures that have the products described before available presented Table 2 1 Examples of manufactures for the solar shading systems studied S Type of solar shading Position Manufacture Website Salha Douglas http www1 hunterdouglascontract com ontract External Warema http www warema de Hagen http www hagen dk Interpane Luxaclair http www luxaclair co uk Venetian blinds Hunter Douglas Contract http www1 hunterdouglascontract com Luxaflex http www luxaflex com Internal Velux http www velux com oe Douglas http www1 hunterdouglascontract com ontract External Verosol http www verosol com Interpane Pellini http www pellini net Roller blinds Verosol http www verosol com Internal Velux http www velux com Colt http www coltinfo co uk Glass lamellas External Artin Douglas http Awww1 hunterdouglascontract com ontract Saint Gobain E o a Glass http www saint gobain glass com Pilkington http www pilkington com Solar control glazings i ae http www saint gobain glass com The evaluation of the performance of different solar shading systems is somehow limited by the lack of information given by the manufactures about the thermal and optical properties of the different materials that compose their products W S has an integrated database where some manufactures have already added the data for their products but this should
92. ference room for Case 2 m REF Meas a amp TEST Meas RN AJ Daylight Factor 3 0 1 2 3 4 5 Distance from the window m Figure 13 8 Measurements at the working plane for both reference and test rooms for Case 2 Figure 13 9 Measurements and simulations at the working plane for the test room for Case 2 Daylight Factor o REF _IESve Rad a TEST_IESve Rad s HA AL 0 1 2 3 4 5 Distance from the window m Figure 13 10 Simulations at the working plane for 79 both reference and test rooms for Case 2 Figures 13 7 and 13 9 show that once again the daylight factors obtained from ESve Radiance simulations are slightly lower than the ones measured especially in the back part of the room Figures 13 8 and 13 10 show that according to both measurements and simulations the glass lamellas allow the homogenization of daylight factor inside the room reducing it near the window Close to the back wall both measurements and simulations registered an increase of 0 1 in daylight factor at 5 4m from the window this improvement is not perceptible in the Figures 13 8 and 13 10 13 3 Case 3 For Case 3 which corresponds to sunny sky the comparison between the measurements and simulations can not be directly done The indoor daylight was evaluated by the illuminance values at the working plane height 0 85 a
93. ffuse light exists 1 3 11 PPD index The PPD index predicted percent of dissatisfied defined in takes into account the influence of all 6 thermal parameters clothing activity air and mean radiant temperature air velocity and humidity and it may be directly used as a indoor comfort criteria 14 15 4 Method to evaluate the performance of different solar shading systems 4 1 The Sofware used Relation between WIS and BuildingCalc LightCalc To evaluate the performance of different solar shading systems two softwares were used WIS3 0 1 developed by TNO Building and Construction Research in Delft 41 and BuildingCalc LightCalc v2 3 1f developed in Matlab at Technical University of Denmark 38 WIS is a European software tool for the calculation of the thermal and solar properties of window systems Knowing previously from the manufactures spectral data for the thermal and optical properties of the materials that compose the different shading systems and also the properties of the glazing panes and gaps it is possible to calculate the properties of combined systems glazing shading system for different angles of incidence Concerning shadings composed of slats that can be tilted it is also possible to calculate the properties for different positions of the slats 3 BuildingCalc LightCalc is a tool that can be used in three different ways only BuildingCalc for thermal simulations only LightCalc for daylight sim
94. ghtCalc a software developed at BYG DTU that can perform yearly simulations for a defined building giving as a result the energy demand for heating cooling and lightning and still indoor comfort evaluation parameters The link between both softwares is that the window systems assessed in WIS can be integrated in the building defined in BuildingCalc LightCalc As acase study a landscaped office room will be simulated for different solutions of solar shading systems The same office room will be studied for two different locations Copenhagen representing a north Europe location and Lisbon representing a south Europe location The result will be the performance of the building in both climates when using different solutions of solar shading systems Some tips on how to use both softwares for the purpose before referred will be presented including some step by step examples Also some suggestions will be given on how to overcome the lack of information characterizing the solar shading systems available in the market 2 Brief introduction to the different types of solar shading systems 2 1 Overview There are many different kinds of solar shading systems available in the market When designing a building besides the aesthetical component also the energy performance and indoor comfort including temperature and daylight must be taken into account A solar shading system must be able to control the solar heat gains in order to reduce the ris
95. ghtcalc it allows to define different settings for different periods according to the correspondent requirements Thus three systems were defined for the coldest months December January and February weeks 1 to 9 and 10 to 53 and three systems for the other months March April May June July August September October and November weeks 10 to 48 The three systems for each season are one for working hours other for non working hours during working days and another one for weekends Two different solutions were studied 1 no mechanical cooling available when there is need for cooling the cooling systems are activated in the following order shading venting and increased mechanical ventilation 2 mechanical cooling available when the previous solutions are not enough to set the indoor temperature to the cooling setpoint the mechanical cooling is activated The first solution is the more environmental friendly since no energy for cooling is used However in most cases this solution is not enough to achieve the indoor comfort level required on 14 specially regarding south Europe countries like Portugal The office is equipped with a heating system with an incorporated heat exchanger with an efficiency of 0 85 The heating system and the mechanical cooling when available are only active during working hours According to 14 the heating setpoint will be 20 C for a cloth level of 1 0 In 14 it is required a cooling s
96. gy consumption for mechanical ventilation kWh m year Energy consumption for hot water KWh m year Vertical illuminance lux Front surface of the solar shading system Shape factor factor de forma Solar heat gain coefficient Green Green reflectance Green transmissivity Luminance cd m Total number of working hours of the mechanical ventilation system h Openness factor Predicted percent of dissatisfied Infrared radiation Indoor infrared emissivity Outdoor infrared emissivity Infrared transmissivity Red Red reflectance xvii RD RGB refl Ra Rough R tn SEL Spec SSC Stdev t tn Tr spec T Tn U value UA value UV radiation V VSC Ww Relative difference Red green and blue reflectances when they are equal General colour rendering index Roughness Red transmissivity Specific electrical power consumption for air transport kJ m Specularity Solar shading coefficient Standard deviation Thickness mm Transmissivity Transmitted specularity Temperature C Visual transmittance Thermal transmittance coefficient W mK Sum of thermal transmission losses through the fagade excluding windows W K Ultraviolet radiation Volume m Visual shading coefficient Slat width mm Slat pitch distance between slats mm Slat angle Cut off angle Solar altitude angle Solar
97. gy demand heating demand cooling demand 2 5 lightning demand 9 Conclusions and further work The combination of WIS and BuildingCalc LightCalc is a very promising tool when evaluating and comparing the performance of buildings with different types of solar shading systems in an early design phase From the simple model of the room and the thermal optical properties of the shadings systems it is possible to calculate in an hourly basis the yearly energy demand for heating cooling and lightning as well as some indoor comfort parameters The method on how to evaluate the performance of different solar shading systems using WIS and BuildingCalc LightCalc was illustrated for a case study a landscaped office building located in Copenhagen and then in Lisbon Different types of solar shading systems were evaluated for the fa ade of the office Apart from small tricks presented through the dissertation the method is quite user friendly When selecting a solar shading system two main characteristics must be taken into account the solar shading performance assessed by g value solar heat gain coefficient and the daylight performance assessed by the ty visual transmittance Usually good shading devices according to solar shading performance are poor in daylight performance It is very important that a solar shading system is flexible to different sky conditions In this way it can be activated during warm and sunny days to avoid the risk of over
98. hading coefficient VSC is defined in a similar way as the solar shading coefficient It is the ratio between the light transmittance of the window system and the light transmittance of the glazing initially defined as the reference In this way for the reference glazing the visual shading coefficient is 1 Higher visual shading coefficient indicates higher visual performance 14 3 7 General colour rendering index Ra This index is used to assess quantitatively the performance of colour rendering through a window system A Ra index of 100 corresponds to perfect colour preservation 27 3 8 Illuminance Illuminance E describes the amount of luminous flux arriving at a surface i e the incident flux per unit area It is measured in lux 1 3 9 Luminance Luminance L describes the light reflected off a surface and it is directly related to the perceived brightness of a surface in a given direction It depends on the illuminance on an object and its reflective properties Luminance is what we see not illuminance Luminance is measured in candelas per square meter cd m 1 3 10 Daylight Factor The daylight factor DLfactor is the ratio of the illuminance on a surface in a room to the illuminance on an external unobstructed horizontal surface taking only the diffuse radiation into account This parameter is usually calculated for evaluating the daylight performance of window systems under overcast skies when only di
99. he shading systems available on WIS is presented 3 Click also on the buttons Specular pane and Gas mix and see the correspondent available databases Specular panes refers to the glass panes and Gas mix to the gas mixtures that can be used to fill up the gaps between the panes 4 Return to W S main window and click on the Transparent System button 5 Create a new record setting the different components of the glazing without shading as presented in Figure A 2 Each line refers to a different component On the first line that refers to the outer pane check the box flip ed to flip the pane Optitherm SN4 glass has a soft coating surface that must be placed facing the gas gap see a detailed description in 3 pages 6 Leave the environment settings as the default option Te Ti 0 20 degrees sun 500 and do not set ventilation in the gas gaps the gaps between the panes are sealed 7 Press the Calculate button to generate the text file for posterior use in BuildingCalc LightCalc A window as the one presented in Figure A 3 will appear The boxes should be checked as they are in Figure A 3 otherwise BuildingCalc LightCalc will not be able to read the text file A 2 EE Transparent system Transparent system a er degrees sn 0 dM Calculate Details Layers EP MT WopitemsnaeiT se RO HM ote ESTE aT wil or i DEF a rea a nl 3 wT ai Ec a vl DEZ ST SE IC MA ll wm wi pre ooo Recor a Ao Figure
100. heating and retracted when solar heat gains and light are needed in the rooms For the case study it was clear the difference between the North Europe Copenhagen and South Europe Lisbon climates regarding the solar shading systems For instance using the same solar system for Lisbon and for Copenhagen the cooling demand in Lisbon is in some cases doubled than in Copenhagen For some cases this cooling demand for the office room in Lisbon is higher than the standard requirement which means that some solutions of shading systems should not be used in Portugal One of the main advantages of BuildingCalc LightCalc is the ability of performing dynamic simulations Different setting for distinct periods of the day working hours and non working hours and year summer and winter can be defined making simulations closer to reality Another benefit is that BuildingCalc LightCalc works with WIS which is a promising database for windows components panes shading devices ect BuildingCalc LightCalc is able to import the text files generated by W S with the thermal optical properties of glazings and shading systems combinations In this way every shading device existing in W S can be simulated in a room using BuildingCalc LightCalc 55 Another important profit from BuildingCalc LightCalc is that it is able to calculate the yearly electrical lightning demand taking into account the hours in which the shading system is activated and in which less da
101. htly satin were assumed to be perfectly diffuse In this case the roughness value is not important since it refers to the specular reflection The specularity of the tables was assumed to be 0 03 and the roughness was set to 0 00 since the tables are polished Table 12 1 RGB reflectances specularity and roughness for the surfaces modelled as plastic material Element R refl G refl B refl Spec Rough Inner walls 0 62 0 62 0 62 0 00 Floor 0 11 0 11 0 11 0 00 Ceiling 0 88 0 88 0 88 0 00 Tables 0 80 0 80 0 80 0 03 0 00 Tables legs 0 60 0 60 0 60 0 00 Measuring points 0 80 0 80 0 80 0 00 Horizontal metallic profiles of the glass lamellas 0 60 0 60 0 60 0 00 Gangway 0 60 0 60 0 60 0 00 Foundation wall 0 60 0 60 0 60 0 00 Grass reflectance 0 20 0 00 0 30 0 00 0 00 12 2 2 2 Glass Material Glazings As it was stated before the glazings of the windows were modelled as glass which is a special case of dielectric material with a refraction index of 1 52 A dielectric material is transparent and it refracts light as well as reflecting it The glass is represented by one single surface which avoids the computation of internal reflections The glass must be defined by the R G and B transmissivity values Transmissivity is the fraction of light not absorbed in one traversal of the material at normal incidence while the transmittance is the total light transmitted through th
102. ially for Lisbon This is due to the possibility that the daylight has to enter the room through the space between the slats However the daylight factors obtained show that also the venetian blinds should be retracted when the sky turns from sunny to overcast in order to decrease the energy consumption for electrical lightning Excluding the reference glazing and the solar control glasses the glass lamellas are the ones that have the best performance during overcast sky even if they are activated for the cut off angle for a previous sunny sky This is due to the high visual transmittance of the glass This system seems to be a promising solar shading system when trying to reduce the number of adjustments in solar shading systems due to sky conditions changes The results also show that the position external interpane and internal of the shading systems do not interfere with the indoor daylight performance External interpane and internal roller blinds have equal performance when evaluated under an overcast sky The same is valid for the venetian blinds if activated for the same cut off angle 46 8 Some tips on how to overcome the lack of data available for solar shading systems As it was stated before there is a lack of information about the properties of the solar shading systems available on the market Most manufactures do not have available the thermal properties of their products and regarding optical properties they only have integrat
103. io de Luz Natural do SBi Danish Building Research Institute para avaliar o desempenho de lamelas de vidro foram comparadas com simula es utilizando o programa ESve Radiance Os resultados mostram que na mairoria das situa es este programa pode ser utilizado para avaliar o desempenho de lamelas de vidro no que diz respeito ao comportamento face luz natural Palavras chave Sistemas de sombreamento solar edif cios de escrit rios energia ilumina o natural lamelas de vidro WIS BuildingCalc LightCalc IESve Radiance vi Contents Acknowledgements Abstract Keywords Resumo Palavras chave Contents List of Figures List of Tables List of Symbols PART A ENERGY AND DAYLIGHT PERFORMANCE EVALUATION OF SOLAR SHADING SYSTEMS 1 Introduction 1 1 Background 1 2 Goal 2 Brief introduction to the different types of solar shading systems 2 1 Overview 2 2 Venetian blinds 2 3 Roller blinds 2 4 Glass lamellas 2 5 Solar control glass 2 5 1 Body tinted glass 2 5 2 Reflective glass 2 6 Market search 3 Some useful definitions 3 1 Electromagnetic spectrum 3 2 Reflectance absorptance and transmittance 3 3 Thermal transmittance coefficient 3 4 Solar heat gain coefficient 3 5 Solar shading coefficient 3 6 Visual shading coefficient 3 7 General colour rendering index Ra 3 8 Illuminance 3 9 Luminance vii vii xi XV xvii q w oon ao 11 11 12 13 13 13 14 14 14 14 15 15 15 8 3
104. is 2 95m long 0 5m wide and 8mm thick The glass used is Antelio Silver from Saint Gobain Glass The visual transmittance of the glass is 66 and the visual reflectance 31 The section of the horizontal metallic profiles in which the lamellas are supported is 8cm high 6cm wide in the largest part and 2 5cm wide in the narrowest part see Figure 11 6 However due to 62 lack of information in the beginning of the simulations it was modelled as 8cm high by 6cm wide in the largest part and 4cm wide in the narrowest part see Figure 11 7 However it was assumed that this difference is not significant on the indoor daylight values Figure 11 5 Picture of the glass lamellas system mounted on the fagade of the Test room 6cm 1 75 cm 2 5 cm 1 75 cm 1 4em 1cm 5 E x x 5 5 5 5 1 25 cm an Figure 11 6 Real section of the horizontal Figure 11 7 Section of the horizontal metallic metallic profiles in which the glass lamellas are profiles in which the glass lamellas are supported supported as they were modelled in ESve 11 2 Measuring conditions The illuminance values were measured with lux meters located in different points of the working plane 0 85m high and ceiling of the experimental rooms The measuring points the same for the Test and Reference rooms and are represented in Figure 11 8 and Figure 11 9 63 0 00m 0 60m 1 20m 1 80m 3 00 m
105. k of overheating and the energy needs for cooling and at the same time control the indoor daylight and avoid glare 1 The optimum solution is a balance between these factors According to 21 usually the products that have low solar transmittance values g value admit almost no daylight into the room and totally obstruct the view out which are two of the main purposes of windows The problem comes when the energy needed for electrical lightning increases more than the decrease of energy for cooling originated by the solar shading systems The solar shading systems should be as flexible as possible so they can adapt to the outdoor conditions In this way they could be activated in summer sunny days to avoid overheating and glare and retracted during overcast days to increase the daylight level inside the room During the winter they should also allow some solar gains to enter the room as a way of reducing the heating load When completely activated at night some solar shading systems may contribute to decrease the thermal transmittance coefficient U value of the window In this way the heat losses through the window from the interior to the exterior of the building are reduced and subsequently also the heating demand The solar shading systems may be characterized depending on their position in the window Thus in accordance with 20 and 21 they can be separated into three groups external interpane and internal As the group names i
106. ling value g WSC ing lightni f 2 j ing lightni y o PositionType Product name Uvalue gwvalue SSC m Ra heating lightning total TC PPD heating cooling lightning total AL CA RL RR A LCA KWh Combinations 47 PikingAricBluesIntVerosolSilverScreenE DO do 018 037 004 006 8 8 16 1818 3 8 o 88 65 256 8 48 PilkingArtic Blue ExtVerosolSilverScreenEDO1 085 003 006 003 0M amp 2o 662 11 8 2 307 647 198 8 49 PilkingArticBluetInt LuxaflexVenBlind4078 TT 06 03 00 00 7 8 4n A 8 9 MM 125 45 UM 8 50 PilkingArticBlue ExtAlumLamellas_60mn do 001 02 00 00 0 do 48 y 8 oo 376 48 150 8 51 SGGReflectGreen IntVerosolRollerED01 66 00 02 00 003 8 W 714 1880 8 0 54 76 Ay 8 52 SGGReflectGreen ExtVerosolRoller EDO 8 002 004 00 00 88 68 69 1816 8 68 30 68B A4 8 53 SGGReflectGreen IntLuxaflexVenBlind4078 TT 009 018 00 00 amp 4 52 40 5 8 40 60 57 204 8 54 SGGReflectGreen ExtAlumLamellas_60mm 8 01 002 0 00 00 0 be 540 14i 8 o 32 50 11 8 For the systems that have orientable slats like venetian blinds and glass lamellas the properties refer to the system completely activated 90 slat position The setpoint for cooling is 2220 so when the mechanical cooling is activated there are no hours above 22 C Total energy demand heating demand 2 5 lightning demand Total energy demand heating demand cooling demand 25 lightning demand ce Table 6 4 Energy and indoor co
107. lmost do not require maintenance The interpane solutions placed in sealed glazing units are free from damage and dirt and do not require to be cleaned solar radiation reflected a and absorbed Sand heat from absorption radiated and convected away E reflected radiation has radiated and convected to pass through glass heat inside room LAA ehh oo Figure 2 1 Heating transfer phenomena that occur on external above and internal below solar shading systems 12 The solar protective glazings are not included in the groups described before but also constitute a type of solar shading system They are integrated in the window replacing the panes The types of solar shading systems evaluated in this dissertation and its main characteristics are next presented These are just a very small part of what is available in nowadays market but are the ones that are possible to simulate with the used software WIS and BuildingCalc LightCalc 2 2 Venetian blinds A venetian blind is a blind composed of parallel spaced slats that can be tilted in order to control the amount of solar gains and light entering the room The slats are available in different widths and can be made of different materials usually wood or aluminium They are also available with different finishes and colours according to the wanted esthetical effect The venetian blinds have the great advantage of being retractable and they can be internal exte
108. lso the standard deviation Stdev is presented In the last column of the table it is presented the relative difference between the results from the ESve Radiance simulations and the measurements The relative difference RD was calculated in the following way DLfactorjesye Radiance DLfaCtOr measurement DLfactor Measurement RD 13 1 Table 13 1 Daylight factors at the working plane for the reference room for Case 1 measurements and IESve Radiance simulations wi En Diference DL factor Dai DL factor E 1 8 0 2 5 4 3 4 The results from ESve Radiance are relatively close to the measurements especially near the window Near the back wall the results from the simulations are around 30 lower than the measurements However despite this difference Figure 13 1 shows that all the results from the simulations are inside the ranges defined by the measurements and correspondent standard deviations 73 25 0 20 0 x S 150 8 m REF Meas r z o REF IESve Rad 10 0 gt oO p 5 0 0 0 r r r r 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 1 Measured and simulated daylight factors for the working plane in the reference room for Case1 The standard deviation is visible for each measurement Indeed since the distant row of trees in the horizon was not modelled it would be expected higher daylight levels fro
109. ly simulations may be performed The main advantage of BuildingCalc LightCalc comparing to Parasol is that also the daylight level inside the room can be evaluated and if it does not fit the requirement electrical lightning will be automatically switched on Also the yearly energy demand for electrical lightning is calculated This is very important when assessing the performance of solar shading systems when using shading systems the decrease in the cooling demand should be higher than the consequent increase in electrical lightning demand Using WIS and BuildingCalc LightCalc it is easy to evaluate the performance of different solar shading systems and select the best option for each specific building However it is not easy for the designer to find information about the thermal optical properties of the solar shading systems available in the market most of the manufactures do not have the thermal properties of their products available and regarding optical properties only integrated data is available Only few manufactures have the complete data available in databases 1 2 Goal The goal of the PART A of this dissertation is to illustrate a simple method on how to assess the performance of different solar shading systems when designing a building The method is based on the use of two different softwares W S which is able to calculate thermal optical properties of windows systems based on the properties of their components and BuildingCalc Li
110. m K for exterior wall roof and ground and 0 68W m K for the window and the heat exchanger has a high efficiency 0 85 The difference comes with the level of indoor comfort With the reference glazing and without mechanical cooling the number of hours of temperature above 26 C is extremely high 1009 hours and the PPD index is 28 which is much higher than the standard maximum 10 When trying to remove the hours of overheating with mechanical cooling the panorama is different from Copenhagen As there are much more hours of overheating the cooling demand to remove them is very high 61kWh m year This value is approximately doubled of 32kWh m year which is 39 the standard maximum cooling demand calculated in accordance with the Portuguese building code 16 This means that even being the sum of the energy for heating cooling and lightning 65kWh m year much lower than the correspondent standard required value 104kWh m year the office building with this reference glazing does not fulfil the standard requirements In this way it is very important to find solutions of solar shading systems that can reduce the cooling demand to a lower value than the requirement 6 4 2 2 The different solar shading systems For the building in Lisbon without mechanical cooling only four solutions of solar shading systems the external roller blinds C16 and C17 and the combinations of solar control glass with external roller blinds 148 and 152
111. m the simulations than from the measurements especially in the back part of the room The mentioned row of trees obstructs the lower part of the sky reducing the incident light in the back of the room However this phenomenon is not visible when comparing the results with the simulations While the part of the room near the window receives mainly directly light from the sky and from outside reflections most of the light arriving to the back part of the room is a result of consecutive reflections on the different surfaces of the room see Figure 13 2 For this reason if the Radiance rendering options are not correctly set when performing simulations the results can be not accurate especially at the back part of the room However different rendering options were tested including the number of bounces which was increased from 5 to 8 and no better results were achieved Another reason for lower daylight factors in the back part of the room when comparing simulations with measurements could be a sub estimation of the reflectances of the inner surfaces of the room As described before most part of the light reaching the back of the room is due to reflections If the reflectances of the inner surfaces are not correctly modelled the daylight factor at the back part of the room can be influenced To evaluate this influence a simulation was performed increasing 5 the reflectance of the following surfaces inner walls floor ceiling and tables In Table
112. mark were performed using a BuildingCalc LightCalc runtime version version that does not need MatLab to run where the option export results is not implemented In this way to get the hours above 22 C and 24 C the simulations would have to be all repeated Besides being time consuming this procedure was not find relevant since the indoor standard requirement only refers to overheating as hours above 26 C 31 cf Table 6 3 Energy and indoor comfort performance of the landscaped office room in Copenhagen for the reference glazing and for the combination of the reference glazing with the different solar shading systems ta U value g value SSC Ty VSC Ra heating lightning total T gt 26 C PPD heating cooling lightning total PPD Posion Type i Cone nape wim k H H E E kWh m _ kWh m kWhim2 h kWh m kWh m kWh m kWh m REF Reference Glazing 0 68 0 49 1 00 0 68 1 00 96 0 55 3 21 8 56 260 12 0 61 22 58 3 21 31 20 7 A Internal Roller Blinds 1 Verosol Roller 818 000 UT light grey 0 60 0 40 0 82 0 33 0 49 95 0 50 3 78 9 94 182 11 0 54 17 83 3 62 27 42 7 2 Verosol Roller 818 741 UT beige 0 60 0 40 0 82 0 35 0 51 95 0 50 3 78 9 94 182 11 0 54 17 83 3 62 27 42 7 3 Verosol Roller 818 936 UT dark grey 0 60 0 40 0 82 0 33 0 49 95 0 47 3 82 10 01 182 11 0 51 17 89 3 66 27 53 7 4 Verosol Roller 875 000 BO light grey 0 54 0 27 0 55 0 03 0 04 94 0 44 8 72 22 24 131 10 0 44 15 02 8 05 35 59 8 5 Verosol Roller 875 936 BO
113. may seem that the decrease in daylight caused by the lamellas is higher for lESve Radiance simulations than for measurements Note In Figure 13 11 for the measuring point closest to the window the daylight level for the simulations of the test room is extremely low when compared to the measurements This is due to a slight difference between ESve Radiance model and reality As it can be seen in Figure 13 13 according to simulations this measuring point marked with a red circle does not receive direct light in opposition to the points that are close to it On the other hand the results show that during measurements the referred measuring point was under the influence of direct light 14291 13143 1366 1506 1447 Figure 13 13 ESve Radiance image Test room under sunny sky for Case 3 May 3 2007 at 10 07 Illuminance 82 13 3 1 Comparing 10 07 to 16 07 In Figures 13 14 and 13 15 the daylight factors for sunny sky at the working plane in both reference and test rooms are presented for measurements and simulations Figure 13 14 refers to May 3 at 10 07 and Figure 13 15 to May 3 at 16 07 100 0 sx gt x n 2 100 5 a REF Meas o 5 o REF IESve Rad 5 4 TEST Meas E A TEST ESve Rad N E 2 gt 2 a 0 1 r r r r 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 14 Measured and simulated daylight factor f
114. mfort performance of the landscaped office room in Lisbon for the reference glazing and for the combination of the reference glazing with the different solar shading systems E U value q value SSC q VSC Ra heating lightning total 1 gt 224C TM To PPD heating cooling lightning total Position Type Product name 4 2 2 2 2 Wim k a do Do jim kW KWhm fh h h Bo hmi KWhm Khm nim REF Reference Glazing 68 049 100 068 100 6 00 154 384 27 154 1009 2 627 15 6510 5 A Internal Roller Blinds 1 Verosol Roller 818 000 UT light grey 60 04 082 033 049 S 02 20 18 965 1220 667 2 02 4765 26 540 5 4 Nerosol Roller 875 000 BO light grey 54 097 055 003 04 4 02 11 96 20 184 I4 4 16 02 4148 10 62 6805 6 0 Verosol SilverScreen white EDOt HT 51 5 05 05 007 4 02 953 OM 182 3 0 4 14 02 3650 84 5759 6 ft Verosol SilverScreen black EBO1 HT 51 5 05 4 06 4 02 981 AS 189 93 M 14 02 3630 868 580 6 B Interpane Roller Blinds 2 Verosol Roller 818 000 UT light grey 72 030 06 32 047 95 2 286 11 3 wl 454 15 03 3706 264 4367 5 3 Verosol Roller 875 000 BO light grey 71 tt 0 22 8 004 94 4 1109 2 75 1566 5 18 10 OM 2284 1004 4198 6 4 Verosol SilverScreen white EDO HT 70 010 02 5 O00 4 4 88 RM AB 504 168 9 04 2050 803 4060 6 5 Verosol SilverScreen black EB01 HT 70 040 02 4 00 9 5 80 23 147 4 amp 3 tl 9 O 1970 Bi 400 6 C Extemal
115. n air conditioning system However these shading systems can slightly reduce the cooling demand Some special attention should be paid to the lightning demand While reducing the solar gains and consequently the cooling demand some solar shading systems also reduce the indoor daylight increasing in this way the need for electrical lightning Sometimes the electrical lightning demand increases more than the cooling demand decreases and the total energy demand is higher with the use of solar shading system than without it this happens in cases A4 A5 A8 A9 Regarding the interpane and external solar shading systems roller blinds and venetian blinds they are enough to without the use of mechanical cooling system accomplish the standard indoor comfort requirements However if better indoor conditions are desired an air conditioning system may be used to completely eliminate the hours in which the temperature is above 22 C it is important to remember that this means a higher total energy consumption In this case even with an increase on electrical lightning demand caused by the shading system the reduction on the cooling demand is such that total energy demand decreases comparing to the reference glazing a reduction to approximately 2 3 of the total energy demand can be achieved with the use of interpane or external roller blinds The interpane venetian blinds can also reduce to 2 3 the total energy demand while the external venetian blinds c
116. nd of course it depends on the luminance level of the sky which is different for the real and modelled skies In this way a parameter similar to daylight factor was defined This parameter named daylight factor for sunny sky DFfactorSS through this dissertation allows an easier comparison between measurements and simulations The difference between DFfactor and DFfactorSS is that the first one only takes into account diffuse light which is valid for overcast skies while the second also takes into account the direct light In Figure 13 11 the daylight factors for sunny sky at the working plane in both reference and test rooms are presented for measurements and simulations The values refer to May 3 at 10 07 The results for 13 07 and 16 07 of the same day are not presented However for the three different instants of the day the relation between measurements and simulations and the use and non use of lamellas is similar apart from a small difference presented further in chapter 13 3 1 Comparing 10 07 to 16 07 In Figure 13 12 the relative difference between daylight factors for sunny sky from ISEve Radiance simulations and measurements is presented for the reference room The values refer to May 3 at 10 07 The relative difference was calculated in the same basis as the relative differences for daylight factors previously described DLfactor SS Esve Radiance DLfactor SS Measurement DLfactorSS measurement
117. ndicate the external are the ones placed on the external ambient side of the window the interpane are the ones placed inside the glazing cavity between panes and the internal are the ones placed on the internal room side of the window According to 21 the external solar shading systems are the most efficient in reducing the cooling loads As they are placed outside they reflect the solar rays before they enter the room Also the heat they absorb is dissipated to the outside air by radiation and convection Figure 2 1 Their main drawback is that as they are placed outside they are more exposed to the atmosphere conditions which can lead to an easier deterioration and higher need for maintenance As a result they need to be more robust Also in accordance with 21 the interpane and internal solar shading have a lower efficiency in terms of avoiding the solar gains This is due to the reflected radiation that has to pass through the glass to reach the outdoor environment Simultaneously and especially in the internal systems the heat absorbed by the shading system is radiated and convected to the inside of the room see Figure 2 1 According to 21 these systems should be used as a component of external devices and their main advantage is the ability to control the amount of daylight and glare inside the room Because of their position on the windows the interpane and internal devices are protected against the outside conditions and a
118. nstance the systems with slats are activated in a way that the orientation of the slats is enough to block the direct sun cut off position For thermal benefits it was assumed that the shading is completely activated during nights and weekends The activation of the shading means extra insulation for the window which is important during winter in order to reduce the heat losses through the window The lightning level is automatically controlled during the working hours When the general indoor daylight is lower than 200lux the electrically lightning will be switched on immediately to reach that level For working areas in landscaped office buildings according to 14 the requirement is 500lux BuildingCalc LightCalc will also keep this level with the use of electrical lightning when needed For general lightning level the wattage of the system used is 4W m while for specific tasks it is 1Wim 5 2 Different settings for Lisbon The goal is that the building in Lisbon is as much as possible similar to the building in Copenhagen so the performance of the different solar shading systems can be compared between North and South Europe countries Only some changes were made The first one is regarding the U value of the exterior solutions The value assumed for Copenhagen 0 1W m K is extremely low for Lisbon since the winter is not so severe in the south Europe countries According to the Portuguese building code 16 the reference U value for
119. of the heat exchanger 0 85 However the building with the reference glazing and without mechanical cooling has some problems of indoor comfort The number of overheating hours above 26 C during one whole year is 206 which is higher than the standard requirement 108 hours Also the PPD index is 12 and it should be lower than 10 These indoor comfort problems can be easily solved with an air conditioning system which leads to a yearly cooling demand of 23kWh m In this case the heating demand increases slightly but the sum of heating cooling and lightning demands is 31kWh m year which is still less than half of the 37 standard requirement calculated before 78kWh m year Thus with air conditioning system the building fulfils the energy and indoor comfort requirements 6 4 1 2 The different solar shading systems In spite of being already in accordance with the standard requirement different solar shading systems were added to the reference glazing With this procedure the goal was to check if when using a solar shading system it is possible to fulfil the indoor comfort requirements without using mechanical cooling And if not how well the shading systems perform reducing the cooling demand As presented in the table of results for Copenhagen Table 6 3 most of the internal solutions for solar shading systems roller blinds and venetian blinds are not enough to accomplish the standard indoor comfort requirements without the use of a
120. ol SilverScreen black EB01 HT half transparent OF 4 f metallic b black 0 50 0 15 0 160 0 810 0 000 0 05 0 75 0 05 0 74 17S SIMPLIFIED_Verosol SilverScreen black EBO1 HT half transparent OF 4 f metallic b black 0 50 0 20 0 500 0 800 0 000 0 05 0 75 0 05 0 74 D Internal Venetian Blinds 50mm air gap between the glazing and the shading 21 Luxaflex venetian blind High Mirror 4078 w 25mm c Omm p 20mm f high mirror b grey stone 0 22 100 00 0 710 0 680 0 000 0 00 0 83 0 00 0 83 21S SIMPLIFIED_Luxaflex venetian blind High Mirror 4078 w 25mm c Omm p 20mm f high mirror b grey stone 0 22 150 00 0 800 0 800 0 000 0 00 0 83 0 00 0 83 F External Venetian Blinds 50mm air gap between the glazing and the shading with free ventilation integrated data based on Warema manufacture 29 SIMPLIFIED Warema Aluminium lamellas 60mm w 60mm c 5mm p 42mm 0 50 150 00 0 800 0 800 0 000 0 00 0 40 0 00 0 40 IR transm IR transmissivity Table 8 7 Comparison of results obtained with complete and simplified data Landscaped office building in Copenhagen system properties without mechanical cooling with mechanical cooling a U value g value SSC Ww VSC Ra heating lightning total T gt 26 C PPD heating cooling lightning total PPD Position T OOD Type Produet name wim k E H H H kWhim kWh m kWhim h kWh m kWh m kWh m kWh m REF Reference Glazing 0 68 0 49 1 00 0 68 1 00 96 0 55 3 21 8 56 260 12 0 61 22 58 3 2
121. om Some daylight measurements and comparison with Radiance simulations are already planned lESve Radiance may be used for this purpose but also a comparison to the original Radiance should be done especially for sunny days with some lamellas opened extra features available in the original Radiance should be used It is very important that the characteristics of the room especially the optical properties of the inner surfaces are well determined so they can be modelled closer to reality For a better understanding of the differences between measurements and simulations it is advised that the person doing the simulations should also be present during the measurements It would be also interesting to evaluate the performance of these glass lamellas systems in real scale buildings located in cities The evaluation should be done by measurements and software simulations and it would be also important to perform a survey in order to collect people s experience of the visual comfort 86 References 1 B low Hube Helena Energy Efficient Window Systems Effects on Energy Use and Daylight in Buildings Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University 2001 2 Danish Building Code http www ebst dk BR95_13_1D33 0 54 0 February August2007 3 Dijk Dick van WIS version 2 0 1 User Guide Examples of windows as input for WIS TNO Building and Construction R
122. om the right window and only its name will be shown 6 In the right window select the text file and choose Menu gt Edit gt Copy Records 7 Go to the WISDATA mab in the left window and choose shadings Choose Menu gt Edit gt Paste records 8 The database manager will now request you to type in a groupname groupname WinDat is not allowed The data will be pasted to the shadings database 9 Now the new shading file is available in the Scattering layers database and ready to be used B 3 B 4 Appendix C Example of how to model glass lamellas from glass pane properties in W S The glass lamellas are not available on the WIS database However they can be generated from the properties of a glass pane a text file with the properties of the glass lamellas defined as a slat system can be created and imported to the shading database Next it is described a step by step example on how to make use of the properties of a glass pane to create a glass lamellas text file The glass lamellas presented are made from the Saint Gobain Glass Antelio Silver 1 Open the Specular Pane window 2 Look for the SGG Antelio Silver pane and make it active as shown in Figure C 1 e name SGG ANTELIO SILVER sgg ID 2860 Info product name SGG ANTELIO SILVER Supplier Saint Gobain Glass Im Group wINDAT 3 1 Iv thickness 6 mm therm conductivity 1 000 W m K corrected emissivity transmittance outdoor indoor k H 0 837 0
123. on the building being studied It was also assumed that the building would have three storeys and instead of choosing one of them for the simulations it was created one that could represent the three at the same time Thus it was assumed that the representative storey would have 1 3 of its ceiling in contact with outside and 19 1 3 of its floor in contact with the ground The remaining parts of the ceiling and floor were assumed to be in contact with heated spaces The inner dimensions of the room will be 20m width so that the lateral walls will not have any influence in the daylight distribution inside the room 10m depth so that the critical point for lightning is included and 3 3m height see Figure 5 1 In this way the landscaped office room has a floor area of 200m It was assumed that 15 people will be working there which means approximately a floor area of 13m per person 3 3m Figure 5 1 Room drawing 5 1 2 The window glazing and frame The window will occupy most of the fa ade It will be 19 65m wide and 2 275m high It will be 0 85m offset from the floor and 0 175m from the lateral walls and ceiling It will be 0 10m inside the wall and no overhangs were considered see APPENDIX E where a detailed drawing of the fagade is presented The window is on purpose placed upper most in the fa ade The working plane will be around the 0 85m offset from the floor A window below that level does not increase the daylight l
124. or sunny sky at the working plane for both reference and test rooms for Case3 The values refer to May 3rd at 10 07 100 0 a g 10 0 S a REF Meas t REF IESve Rad 2 4 TEST Meas E a TEST IESve Rad 10 o cc 0 1 T T T T T 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 15 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case3 The values refer to May 3rd at 16 07 Comparing Figure 13 14 to Figure 13 15 it can be seen that the measurements and simulations are closer at 16 07 and at 10 07 especially in the middle of the room 83 As referred before there is a constant difference between the measurements and simulations In the middle and back parts of the room the results from simulations are constantly slightly lower than the measurements However at 16 07 the simulations are closer to the measurements The reason may be the group of trees close to the experimental rooms towards south west direction that was not modelled During the afternoon this group of trees blocks partially the light coming from the sun see Figure 11 3 where the view out from the experimental room is shown 13 4 Case 4 The comments made before for Case 3 are also valid for Case 4 since the results are very similar for both cases The main difference is that according to the measurements for instance a
125. or these products the complete data is available in WIS database and some properties are presented in Table 6 2 and Table 8 6 49 Table 8 3 Data used in W S based on available data from the manufacture and assumptions previously suggested Verosol 818 000 40 OF Verosol SilverScreen black EBO1 4 OF Geometry Thickness 0 18mm Thermal properties Material conductivity 0 2W mk IR emissivity outdoor 0 5 IR emissivity indoor 0 8 IR transmissivity 0 Optical properties ts 0 44 ps 0 34 tv 0 44 pv 0 33 tuv 0 43 puv 0 34 Only direct transmission Only diffuse reflection No incidence angle dependence except for the 90 and 90 for which there is only reflection and no transmission Geometry Thickness 0 5mm Thermal properties Material conductivity 0 2W mk IR emissivity outdoor 0 5 IR emissivity indoor 0 8 IR transmissivity 0 Optical properties ts 0 05 ps 0 75 tv 0 05 pv 0 74 tuv 0 05 puv 0 75 Only direct transmission Only diffuse reflection No incidence angle dependence except for the 90 and 90 for which there is only reflection and no transmission Assumptions 8 2 2 Venetian Blinds Regarding venetian blinds two different examples were chosen 1 Luxaflex Venetian Blind High Mirror 4078 D21 2 Warema aluminium lamellas 60mm Raffstoren 94 A6 RAL 9006 F29 While the first one refers to an internal venetian blind from Luxaflex manufacture
126. ormed for Case 2 11 2 3 Case 3 Case 3 corresponds to the situation in which all the lamellas are closed During a day of clear sky with full sun May 3 2007 the illuminance was measured for the working plane points represented in Figure 11 8 The measurements were registered every 30 seconds during whole the day but only three instants of the day were chosen for this study The chosen times are 10 07 morning 13 07 noon and 16 07 afternoon The global horizontal illuminance measured on the roof was 62608 lux at 10 07 76779 lux at 13 07 and 62631 lux at 16 07 11 2 4 Case 4 In Case 4 the two upper lamellas are opened to 30 while the others are closed During a day of clear sky with sun but with some periods of white clouds May 18 2007 the illuminance was measured for the working plane points represented in Figure 11 8 The measurements were registered every 30 seconds during whole the day but only three instants of the day were chosen for this study The chosen times are 10 07 morning 13 07 noon and 16 07 afternoon The global horizontal illuminance measured on the roof was 67444 lux at 10 07 82670 lux at 13 07 and 67392 lux at 16 07 66 12 Modelling in ESve Radiance 12 1 The method Radiance uses a ray tracing method to generate virtual images of the scenes see APPENDIX G In these images the daylight levels can be read As shown in Figure 12 1 the rays are randomly send from the focus of a virtual ey
127. ota Toc PPD heating cooling lightning total Position Type Product eee CA CA CA PR RG RCA kW RW kWh Interpane Venetian Blinds Luxaflex venetian blind 8 Perfor 2053 or 05 00 00 9 47 4 34 dt 93 9 4 NO 42 26 8 25 Luxaflex venetian blind 8 Perfor 6127 57 03 047 02 00 A 45 4 y 9 471180 43 2B 8 26 Luxaflex venetian blind 8027 5B 02 04 0 76 494 33 3d B 9 9 tin 4 AU 8 27 Luxaflox venetian blind High Mirror 4078 57 007 04 0 91 8 4 B 8 9 48 115 41 24 8 28 Luxaflex venetian blind Thermostop 2383 5 009 018 0 16 424 83 B 8 9 Mo UM 4 AA 8 F External Venetian Blinds 29 Aluminium lamellas_ 60mn 62 001 00 0 0 67 4 14 Do 0 8 67 400 409 14 88 8 30 Aluminium lamellas 80mn 62 o 00 0 0 67 40 82 0 8 67 460 400 1530 8 31 Aluminium lamellas_ 100mm 62 o 00 0 0 67 40 82 0 8 67 466 40 1598 8 G External Glass Lamellas 32 SGG Antelo Silver 500mm O 08 057 02 2 y 84 ou 9 o 92 45 2009 8 33 SGG Antelio Clear 500mm o 0 04 05 02 9 99 AS no 9 99 665 45 1826 8 34 SGG Reflectasol Grey 500mm 638 012 024 008 042 8 Mo 48 120 3 9 Mo 5 44 15H 38 35 Glav_Stopsol Silverlight Green 500mm o 07 035 013 09 8 Bo 42 5 18 9 08 531 46 167 8 H Solar Control ae 36 Pilkington Artic Blue 96 08 08 02 06 65 Mo 36 d2 106 0 92 1231 3 BM 8 37 Pikington Opttlot Clea 08 14 01 14 O 10 34 BM BM 1
128. ould have a higher thickness and a more resistant finish It should also be mounted in side runners so it is more protected from the wind loads V 14 tat IN 14 PN IN PN PN PA A C Figure 2 3 Schemes of external A interpane B and internal C roller blinds 17 and 40 i 2 4 Glass lamellas The glass lamellas are another type of external solar shading systems Figure 2 4 They are composed of orientable glass lamellas supported by a metallic structure Besides controlling the solar gains contributing to reduce the overheating and the energy demand for cooling they also control the daylight They may improve the daylight conditions by redirecting the light further into the room where it is most needed 18 L E k A Figure 2 4 Glass Lamellas Model CARRIER SYSTEM 1 from COLT manufacturer 24 The glass lamellas can be set in different angles according to the function they need to perform Thus in sunny days they can be tilted as a solar shading system in order to block the direct sun rays while in overcast days they can be tilted in a way that they reflect the daylight into the room increasing the indoor daylight levels especially far from the window see Figure 2 5 The solar transmittance of the glass lamellas is reduced adding to its surface black dots silkscreen printed pattern or solar control coatings next described A B Cc Figure 2 5 Glass Lamellas in sola
129. oup at BYG DTU for the technical support with lESve software Thank you to Sara Anders Martin and Anders my colleagues in my office Thank you for the great working atmosphere would also like to thank my family here in Denmark the Erasmus community You coloured my time here Special thanks to Sonia Maria and Victoria for the great moments spent here Pedro thank you for all the support especially during the last weeks Special thanks to all my friends and family in Portugal can not forget names as In s Ana Helena Joao Fung Guilherme and Jo o Dias Jo o Ramos Marcelo and Ricardo thank you for the great moments in Scandinavia Finally would like to thank my parents Luis and Cristina and my sisters Sara Joana and Beatriz Thank you for the unconditional support and for making possible my Erasmus semester at DTU Sara thank you for the great help with the graphic part of this dissertation Abstract This dissertation is composed of two parts Part A and Part B In Part A a user friendly method of how to evaluate the performance of different solar shading systems during an early design phase of a building is illustrated The method is based on the use of WIS and BuildingCalc LightCalc simulation tools The solar shading systems integrating a building may be dynamically controlled and the energy and daylight performances of the building may be evaluated A case study of a landscaped office building in which differ
130. p 1204 18544 18441 19686 42951 41363 Figure G 2 Reference room under sunny sky for Case 4 May 18 2007 at 13 07 Illuminance values lux Figure G 4 Reference room under sunny sky for Case 4 May 18 2007 at 13 07 Illuminance values lux G 1
131. previously suggested Luxaflex Venetian Blind High Mirror 4078 Warema aluminium lamellas 60mm Raffstoren 94 A6 RAL 9006 Geometry thickness 0 22mm slat chord width 25mm crown height 2mm slat pitch 20mm Thermal properties Material conductivity 150 W mk IR emissivity outdoor 0 8 painted surface IR emissivity indoor 0 8 painted surface IR transmissivity 0 Optical properties ts 0 ps 0 83 tv 0 pv 0 83 tuv 0 puv 0 83 Optical properties equal for both sides Geometry thickness 0 5mm slat chord width 60mm crown height 5mm slat pitch 52mm Thermal properties Material conductivity 150 W mk IR emissivity outdoor 0 8 painted surface IR emissivity indoor 0 8 painted surface IR transmissivity 0 Optical properties ts 0 ps 0 4 tv 0 pv 0 4 tuv 0 puv 0 4 Optical properties equal for both sides Assumptions 51 8 2 3 Results and Discussion For a better understanding of the different results when using simplified and complete data the complete data from WIS and simplified data from manufacture and assumptions for the analysed solar shading systems are presented in Table 8 6 The spectral optical properties are not presented but can be consulted in the W S database In Table 8 7 the results of the performance of the landscaped office room in Copenhagen obtained when using complete and simplified data are presented When simplified data
132. r Figure 2 5 Glass Lamellas in solar shading position A and B and in daylight position C Figure 2 6 Spectral transmittance depending on the angle of incidence q for the Pilkington Suncool Brilliant 66 33 solar control glass Figure 2 7 Spectral reflectance depending on the angle of incidence 9 for the Pilkington Suncool Brilliant 66 33 solar control glass Figure 2 8 Spectral absorptance depending on the angle of incidence q for the Pilkington Suncool Brilliant 66 33 solar control glass Figure 5 1 Room drawing Figure 6 1 Venetian blind geometry Figure 6 2 Solar shading coefficients for the different solar shading systems Figure 7 1 LightCalc picture of the room showing point A x 10m y 8m z 0 85m where the daylight factor was determined for each solution of solar shading system combined with the reference glazing Different colours represent different levels of daylight factor Figure 7 2 Cut off position for a solar shading system composed of slats Figures a and b refer to different positions of the sun Figure 7 3 Drawing of a building fagade with the representation of the solar altitude angle 8 solar azimuth angle y and profile angle 0 Figure 7 4 Drawing of a slat system showing the profile angle 6 the cut off angle ac the slats width w and the distance between slats p Figure 11 1 Picture of the Daylight Laboratory at SBi Figure 11 2 Geometry of the experimental rooms of th
133. r protective glasses studied on this dissertation were the body tinted glasses and the reflective glasses 2 5 1 Body tinted glass The body tinted glass is a normal float clear glass into whose melt colorants were added for tinting and solar radiation absorption properties This reduces heat penetration in buildings These coloured glasses are an important architectural element for the exterior appearance of fa ades but they have a significant negative effect on the colour of the transmitted light 26 2 5 2 Reflective glass The reflective glass is an ordinary float glass with a metallic coating to reduce solar heat This special metallic coating also produces a mirror effect There are two different types of coatings hard coatings on line coated and soft coatings off line coated The hard coating glasses result from a pyrolitic process in which semi conducted metal oxides are directly applied to the glass during the float glass production while the glass is still hot These hard coatings are very resistant to mechanical damage and relatively harmful to the environment The soft coatings glasses are originated from a vacuum magnetron process in which one or more coats of metal oxide are applied under a vacuum to finished glass The coatings applied by this technique are soft and must be protected against external influences and are therefore used in sealed glazing units 17 11 2 6 Market search In Table 2 1 a list of some manu
134. r shading position A and B and in daylight position C 18 2 5 Solar control glass The solar control glass is also a way of controlling the solar gains reducing the risk of overheating and the energy demand for cooling This type of glass has a low transmittance in the near infrared reducing the solar heat gains 12 At the same time a solar control glass should have a high visible light transmittance in a way that it does not compromise the daylight inside the room In Figure 2 6 Figure 2 7 and Figure 2 8 the diagrams of spectral transmittance reflectance and absorptance are presented for a solar protective glass used in this dissertation The graphs show that it is a selective glazing with higher transmittance in the visible part of the spectrum and lower on the infrared and ultraviolet parts Spectral Transmitance 300 500 750 1000 1250 1500 Lambda nm Figure 2 6 Spectral transmittance depending on the angle of incidence q for the Pilkington Suncool Brilliant 66 33 solar control glass 27 Spectral Reflectance 300 500 750 1000 1250 1500 Lambda nm Figure 2 7 Spectral reflectance depending on the angle of incidence q for the Pilkington Suncool Brilliant 66 33 solar control glass 27 10 Spectral Absoptance 300 500 750 1000 1250 1500 Lambda Cnm Figure 2 8 Spectral absorptance depending on the angle of incidence q for the Pilkington Suncool Brilliant 66 33 solar control glass 27 The sola
135. rnal or interpane see Figure 2 2 According to the place where they are going to be mounted they have different requirements For instance an external venetian blind needs to be more resistant and robust higher width and thickness than an internal one A narrower slat will reduce the view of the outside when the slat is angled for effective solar protection gt Fa gt A Pd Poa Ed E dl F Fi AZ BIZ ci 7 Figure 2 2 Schemes of external A interpane B and internal C venetian blinds 40 The slats can be also vertical but its calculations are not yet implemented in the W S software The reason for this is that angular calculations are only performed for different altitude angles The azimuthal angle is always assumed to be normal to the window Therefore variations in the angle of incidence altitude angle have no effect on the transmission and reflection of vertical blinds 17 2 3 Roller blinds A roller blind is a retractable blind made of a flexible material which is flat when drawn They are available in different fabrics which can be more or less transparent according to their openness factors The fabrics can have a metallic or non metallic finish and are available on different colours The roller blinds can be external internal or interpane see Figure 2 3 but they have different requirements depending on where they are going to be mounted For instance a roller blind for external use sh
136. rooms using ESve Radiance 39 and assess how close to the measurements can the results from the simulations be lESve Radiance is a simplified and user friendly version of the original Radiance The purpose is to test how accurate is ESve Radiance assessing the daylight performance of rooms where glass lamellas are applied 59 11 The Daylight Laboratory at SBi 11 1 Description of the experimental rooms 11 1 1 Geometry The Daylight Laboratory in Horsholm Denmark consists of two identical experimental rooms raised 7m above the ground to minimise shading from surrounding buildings and trees see Figure 11 1 The latitude and longitude of Daylight Laboratory are 55 86 north and 12 49 east respectively and the rooms are oriented 7 5 east of the exact south direction Figure 11 1 Picture of the Daylight Laboratory at SBi The two experimental rooms are identical each measuring 3 5m width by 6 0m depth with a floor to ceiling height of 3 0m see Figure 11 2 0 06 m 0 66 m 0 08 m 1 42m 3 00 m 0 78m 0 86 m 1 78m 0 86 m 3 50 m Figure 11 2 Geometry of the experimental rooms of the Daylight Laboratory at SBi 60 11 1 2 Landscape The space in front of the experimental rooms is a field of grass and it is essentially empty from obstructions apart from the distant row of trees towards south and the group of trees towards the south west direction
137. rstanding 75 Table 13 4 Daylight factors at the ceiling for the reference room for Case 1 measurements and IESve Radiance simulations window m em i 9 DL factor Stdev DL factor Diference as O 06 0 336 45 47 i8 23 ois 26 J 130 Lo 30 075 14a 67 42 41 0048 og 82 54 o8 040 o7 its As for the working plane the results from simulations are higher than the measurements near the window and lower in the back part of the room However the relative difference between the simulations and measurements in the back part of the room is lower than for the working plane Opposite to the simulations results for the working plane the simulations results for the ceiling do not fit so well in the ranges defined by the measurements and correspondent standard deviations The standard deviation values are lower Anyway the results are quite close to the measurements see Figure 13 3 5 0 4 0 ze S 30 E E m REF Meas z rT o REF IESve Rad 2 0 Fy a F 1 0 ki E 0 0 7 7 1 7 7 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 3 Measured and simulated daylight factors at the ceiling in the reference room for Case1 The standard deviation is visible for each measurement 13 1 2 The test room 13 1 2 1 The working plane In Table 13 5 the SBi measurements and ESve Radiance results for the daylight
138. s Roller blinds thickness The shading system geometry must Geometry Slat shading device thickness slat chord width crown height slat be given bythe manufacture pitch Roller blinds assume 0 2W mK for ordinary fabrics Thermal properties Material conductivity Venetian blinds assume 150W mK for aluminium slats 47 Table 8 1 Cont 1 Tips on how to use simplified data from manufactures Thermal properties Cont Material IR emissivity outdoor indoor Assume 0 5 for metallic surfaces and 0 8 for non metallic surfaces Material IR transmissivity Assume that it is zero Optical properties Roller blinds Integrated data solar visual and UV for outdoor and indoor transmittance and reflectance for different angles of incidence the values must be separated into direct and diffuse components Roller Blinds Assume that the optical properties are equal for the different angles of incidence However assume that for 90 or 90 angles of incidence there is only reflectance and no transmittance Assume that all of the transmittance is direct and that all of the reflectance in diffuse Assuming that the transmittance is direct is valid for the normal angle of incidence For different angles of incidence the shape of holes has an influence on the direct and diffuse components of the transmittance through the fabrics Through thick and long holes tunn
139. s the solar shading systems were integrated in the landscaped office building in Copenhagen The purpose is to compare the results between the use of complete and simplified data and analyse the influence of the proposed simplifications and assumptions on the final performance of the office room The goal is also to demonstrate whether or not results closer to reality can be obtained when using simplified data 8 2 1 Roller blinds Two different fabrics for roller blinds with different openness factors OF were chosen 1 Verosol Roller 818 000 40 OF A1 2 Verosol SilverScreen black EBO1 4 OF A11 and C17 The first one was assessed as internal roller blind and the second as internal and external 8 2 1 1 Data available from manufacture In Table 8 2 the data available from Veroso manufacture website 35 for both roller blind fabrics is presented Table 8 2 Data available from the manufacture Verosol 818 000 40 OF Verosol SilverScreen black EBO1 4 OF thickness 0 18mm ts 0 44 ps 0 34 ty 0 44 pv 0 33 tuv 0 43 front surface metallic back surface non metallic thickness 0 5mm ts 0 05 ps 0 75 ty 0 05 pv 0 74 tuv 0 05 front surface metallic back surface non metallic 8 2 1 2 How to use the data available from the manufacture In Table 8 3 the data used in WIS based on available data from the manufacture Table 8 2 and assumptions previously suggested Table 8 1 are presented F
140. s and glass lamellas the properties refer to the system completely activated 90 slat position The setpoint for cooling is 2220 so when the mechanical cooling is activated there are no hours above 2220 Total energy demand heating demand 2 5 lightning demand Total energy demand heating demand cooling demand 25 lightning demand ac Table 6 4 Cont Energy and indoor comfort performance of the landscaped office room in Lisbon for the reference glazing and for the combination of the reference glazing with the different solar shading systems a Uvalue gvalue SSC m VSC Ra heating lightning tota TC TM TC PPD heating cooing lightning tota Position Type Produci 2 2 2 2 2 2 2 o kWh im kWhim kWh fh h h Do kW Whim KWh kWhim 9 G External Glass Lamellas 32 SGG Antelio Silver_500mm O 08 057 00 09 4 DM 35 89 604 69 W 3 Mo aA IB VB 6 33 SGG Antelio Clear 500mm B 021 08 015 02 9 06 376 04 15 6660 2 1 06 AB 348 RA 6 34 SGG Reflectasol Grey 500mm 63 02 04 008 02 amp 07 381 958 1403 O 28 1 07 AB 351 UB 6 35 Glav_Stopsol Silverlight Green 500mm 6 07 05 013 019 B 0 362 9 o m 2 1 O 2150 34 299 6 H Solar Control Glazings 36 Pilkington Artic Bue 68 049 100 052 06 9 06 1495 48 dim W 49 tj 06 SAB 18 425 f 40 Pilkington Suncool HP Silver 50 30 65 05 01 043 08 y DM 215 542 1705 88 38 4 0 388 215 373 6 41 SSG Antelio Silver 66 029 059 04 090 B o 18 452 190 128 689 3 O 484 180 53
141. see Figure 11 3 Figure 11 3 Landscape view from the Reference room of the Daylight Laboratory at SBi 11 1 3 The windows Each room has two windows one larger in the middle of the fagade and another one smaller upper in the fagade The larger window is 1 78m wide by 1 42m high and it is 0 78m from the floor The smaller one is 1 78m wide by 0 66m high and it is 0 08m offset from the larger window Both windows are centred with respect to the lateral walls see Figure 11 2 The windows of the experimental rooms are double pane assembly with a low emissivity coating and argon filling from Pilkington Optitherm S The U value in the middle of the glazing is 1 1W m K and the light transmittance is 72 8 11 1 4 Walls floor and ceiling The walls of the experimental rooms are covered with light grey wallpaper which is an almost perfectly diffusing surface The ceiling is made of white suspended ceiling tiles and the floor is covered with a dark grey carpet The reflectance values for the different surfaces are presented in Table 11 1 8 Table 11 1 Reflectance values for the walls ceiling and floor of the experimental rooms Surface Reflectance Walls 62 Ceiling 88 Floor 11 61 11 1 5 The furniture The experimental rooms are furnished with two tables each The tables size is 0 75m by 1 5m and they are centred with respect to lateral walls The first one is 0 64m offset from the window while the se
142. some examples of how to use WIS and BuildingCalc LightCalc are presented In APPENDIX A a step by step example of how to use WIS and BuildingCalc LightCalc for the purpose of this dissertation is presented The given example refers to an internal venetian blind applied on the glass fa ade of the landscaped office building described on chapter 5 Case Study Landscaped Office Building In APPENDIX B the way how to add a new shading system to the W S database is presented In APPENDIX C an example of how to model glass lamellas from glass pane properties using WIS is presented In APPENDIX D some tips are given on how to import the glass lamellas to BuildingCalc LightCalc 18 5 Case study Landscaped office building Office buildings with glass fa ades are more and more common The transparent properties of the glass enable the natural light to come into the buildings allowing high levels of indoor daylight which is positive it is known that people prefer working and have higher efficiency under natural light and at the same time the cost for electricity and the CO emissions decrease The drawback is that the glass fa ade is where the main solar gains and heat losses occur The solar gains during winter are useful in decreasing the need for heating But during summer the excess of solar gains give raise to many hours of overheating The indoor comfort could be simple reached with an air conditioning system but this would lead to v
143. stribution of light coming from the window This very high accuracy is extremely time consuming and may be not enough In the original version of Radiance there is a special algorithm mkillum that is able to transform surfaces in the room into light sources In this way the process can be separated into two parts first the window is transformed into a light emitter taking into account the light from sun and sky and the effect of the glass lamellas and after the daylight simulation inside the room is performed without taking into account the exterior environment but only the window as the light emitter 5 Detailed information about this Radiance feature is available in 5 and 22 This method is much more effective but is not available in ESve Radiance This can be the reason for the non accordance between simulations and measurements for a sunny sky regarding the effect of the opened glass lamellas in the back part of the room Note In Figure 13 16 for the second measuring point closest to the window the daylight level for the simulations of the test room is extremely low when compared to the measurements As it happened before with Case 3 see Figure 13 11 this is due to a slight difference between ESve Radiance model and reality As it can be seen in Figure G 4 Appendix G according to simulations the referred measuring point marked with a red circle does not receive direct light This point is on the shadow of one of the hori
144. systems to assure that simplified data can be used in any case in the early design phase to assess the performance of solar shading systems The main problem of not using spectral data could be when evaluating the performance of solar shading systems regarding the influence that they have in the colour of the light that enters the room Using integrated data solar shading systems with different colours can not be distinguished the indoor light colour will be the same 53 vs Table 8 6 Comparison of the complete and simplified data of the solar shading systems thermal properties optical properties ID Position Type Product name Description tim Wim Reo _IR enal IRtransm cof psi wh pi A Internal Roller Blinds 50mm air gap between the glazing and the shading 1 Verosol Roller 818 000 UT light grey ultra transparent OF 40 f metallic b light grey 0 18 0 20 0 510 0 811 0 158 0 44 0 34 0 44 0 33 1S SIMPLIFIED_Verosol Roller 818 000 UT light grey ultra transparent OF 40 f metallic b light grey 0 18 0 20 0 500 0 800 0 000 0 44 0 34 0 44 0 33 11 Verosol SilverScreen black EBO1 HT half transparent OF 4 f metallic b black 0 50 0 15 0 160 0 810 0 000 0 05 0 75 0 05 0 74 11S SIMPLIFIED_Verosol SilverScreen black EBO1 HT half transparent OF 4 f metallic b black 0 50 0 20 0 500 0 800 0 000 0 05 0 75 0 05 0 74 c External Roller Blinds 50mm air gap between the glazing and the shading with free ventilation 17 Veros
145. t gt direct beam gt diffuse direct gt diffuse WL nm outdoor indoor outdoor indoor outdoor indoor outdoor indoor i 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 of 1 Filtered Figure B 1 Table where the spectral data for the new shading system are defined valid for roller blinds and slat shading systems B 1 EE Solar Shading direct gt direct assumed independent of type of radiation solar visual or uv no name specified direct diffuse i 5 5 5 5 5 Wf fooo wan 7 0007 0 00 im WE po Bo noo ooo ooo 0 00 0 00 0 00 O00 000 E e 000 000 000 ooo ooo 0 00 ooo ooo ooo ooo ooo 0 00 000 O00 o E ooo 0 00 0 00 0 00 ooo Be Be i 0 00 0 00 0 00 0 00 ooo f 0 00 E 0 00 m m 0 00 0 00 E 0 00 e m ae 00 0 00 0 00 ed 0 00 0 00 000 0 00 0 00 0 00 m 0 00 00i Tor 0000 00 EE 20 J i me A SAEIA TRUA 0 00 00 0 00 20 0 00 0 00 eager 0 00 0 00 0 00 0 00 10 0 00 0 00 0 00 0 00 0 00 0 000 000 ooo 0 00 0 00 o E 0 00 0 00 0 00 0 00 mn 0 00 0 00 0 00 no ES j ooo o00 0 00 ooo E Ta 000 0 00 0 00 a tT 0 00 0 00 0 00 60 000 000 ooo ooo 70 0 00 O00 0 00 0 00 80 0 00 0 00 0 00 0 00 90 000 0 00 0 00 0 00 Return Figure B 2 Table where the integrated data for a new roller blind system are defined for different angles of incidence Sla
146. t 13 07 the daylight in the back part of the room is higher in the test room than in the reference room Comparing to Case 3 this means that the two upper lamellas which are set in the 30 position see Figure 11 10 are able to increase the daylight in the back part of the room On the other hand according to the simulations the lamellas are not able to increase the light in the back of the room Instead they decrease it see Figure 13 16 100 0 L gt x n 10 0 S sa REF Meas 5 o REF IESve Rad 5 4 TEST Meas 8 a TEST IESve Rad gt gt a 0 1 r r r 1 1 0 0 1 0 2 0 3 0 4 0 5 0 6 0 Distance from the window m Figure 13 16 Measured and simulated daylight factor for sunny sky at the working plane for both reference and test rooms for Case4 The values refer to May 18 at 13 07 According to 5 when modelling in Radiance rooms in which the windows have complex shading systems as slat systems usual simulations do not give accurate results especially for sunny days in which the amount of light coming into the room is larger and concentrated in one direction Most 84 of the light coming through the window from the sun and sky is interreflected by or transmitted through the shading device before coming into the room In this way very high accuracy in the indirect calculation options settings is necessary to properly sample and represent the di
147. t integrated data name no name specified E R upper side outdoor o 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 T both sides equal 0 000 0 000 f 0 000 0 000 0 000 0 000 IR properties IR emissivity upper side outdoor 0 900 Figure B 3 Table where the integrated data for a new slat shading device are defined only normal angle of incidence B 2 Importing a text file This is a different way of adding a new shading system to the W S database The first step is to create a text file with the format of the examples presented on 17 To import the text file to W S database the procedure next presented must be followed 1 On the Scattering layer window create a new record B 2 2 Click on the button Import from text file A new window will be displayed answer Yes The WIS database manager will be initialized 3 On the WIS database manager choose File gt Open gt WIS database Open the database that you are currently using is WIS by default its name is WISDATA mab 4 Now you need to open the text file you created before Choose File gt Open gt Text files A new window will be presented Select Spectral shading data Next select the text file you created and open it The content of the text file will be presented in the right window 5 In the left window go one level up by clicking on the folder where your text file is stored The content of the text file will disappear fr
148. thermal transmittance W mK 0 056 5 1 3 Type of construction and furniture It was assumed that the U value of all the solutions in contact with the outside would be 0 1W m K for wall roof and floor According to the assumptions previously mentioned this means an overall UA value of 15 46W K This value takes into account the sum of transmission losses through the elements facing outside excluding windows For simplifying reasons the linear transmittance losses through the thermal bridges were neglected In the BuildingCalc userguide 11 there are already some predefined classes and values for the heat capacity of buildings It was assumed that the type of construction of the office is middle light which means few heavy parts which corresponds to a total heat capacity of 5 76x10 J K This assumption takes into account that usually in landscaped office buildings the solutions for the floor and ceiling are false to allow the installations to be placed inside Also the partitions are made of very light materials 21 Additional heat capacity of the furniture was considered Taking into account that there are 15 working places that each one has a weight of 200kg and that the heat capacity of each kg is 1000J K the total contribution of the furniture is 3x10 UK 5 1 4 Systems Six different systems were defined to simulate different periods of the year and distinct using conditions This is one of the great advantages of BuildingCalc Li
149. tilation is set 2871h working hours airchange rate is the required airchange rate for indoor air quality 0 9h SEL is the specific electrical power consumption for air transport 2kJ m V is the inner volume of the office room 660m A is the floor area 200m and 1 3600 is the factor to convert kJ to kWh In this way the total energy demand for mechanical ventilation multiplied by the factor 2 5 is 11 8kWh m year Regarding hot water the typical consumption for an office building is 1001 per m per year which corresponds to an energy consumption Enw of _ 100 Cy x AT mw lkWa m year 6 4 Where 100l m year is the standard hot water consumption for an office building as referred before Cy is the specific heat capacity of the water 4187J kg C AT is the temperature increase needed for the production of hot water 45 C and 1 3600000 is the factor to convert J to kWh Thus the energy demand for hot water is 5 2kWh m year The sum of the energy for mechanical ventilation and hot water is 17kWh m year and it is constant for all the different solutions for solar shading systems This means that to fulfil the Danish building code requirements the sum of energy for heating cooling and lightning must be lower than 78kWh m year 95 17 78 kWh m year However for the nowadays need of saving energy at least half of this value should be expected 78 2 39 kWh m year 6 1 1 2 Portugal According to the Portuguese buil
150. ts approximately 40 of the energy from the sun 4 A gt 2500nm IR radiation all the surfaces at room temperatures emit energy in this interval Ordinary window glass is not transparent for these wavelengths however the radiation is absorbed and then re radiated towards indoor and outdoor environments A major part of the heat loss through an ordinary window occurs in this way 1 3 2 Reflectance absorptance and transmittance The glazings and the materials that compose the shading systems can be characterized according to their solar optical properties reflectance absorptance and transmittance The reflectance p is the fraction of the incident flux that is reflected from the glazing or shading material the absorptance a is the fraction of incident flux absorbed by the glazing or shading material and the transmittance t is the fraction that is transmitted through them The sum of the reflectance absorptance and transmittance must be equal to the unit p a t 1 The solar transmittance ts is the glazing or shading material transmittance over the whole solar spectrum while the visual transmittance ty refers to the transmittance only for the visible range of the solar spectrum In a similar way also the ultraviolet transmittance tuv can be defined Manufacturers usually give the visual transmittance because it determines how well one can see through a window and how much natural light can be used in the building to illuminate tasks
151. ulations and BuildingCalc LightCalc for combined simulations With BuildingCalc LightCalc it is possible to create a simple model of a room and import from WIS the properties of the solution for the window glazing shading system In an hourly basis dynamic simulation BuildingCalc LightCalc is able to calculate the needs for heating cooling and lightning during one whole year Also an evaluation of the indoor comfort is made and parameters as total hours of overheating and PPD index predicted percent of dissatisfied are calculated The indoor daylight conditions can also be studied for a specific day and hour 11 Combining these two softwares it is possible to do some calculations early in the design phase to evaluate and compare the energy and daylight performances of different solutions of solar shading systems 16 4 1 1 WIS With WIS it is possible to simulate a complete window system including glazing solar shading system frame and spacers However for posterior use in BuildingCalc LightCalc only the transparent system solar shading glazing is necessary to be set The properties of the frame and spacers are set separately in BuildingCalc LightCalc Thus in this dissertation the objective of using W S is to generate text files that characterize the transparent systems glazing solar shading in a way that they can be used in BuildingCalc LightCalc In WIS there are already available databases with commercial solutions for
152. ust be nine see Table C 1 Add the columns that are missing in Microsoft Excel interface Assume that the front and back surfaces transmittances are both equal to the glass pane transmittance and assume that the transmittance and reflectance are always direct and never diffuse Table C 1 Columns needed for the glass lamellas text file Column number Content Description 1 Wavelength 2 Tfn dir Direct transmittance front surface 3 Tfn ditt Diffuse transmittance front surface 4 Tbn dir Direct transmittance back surface 5 Tbn aitt Diffuse transmittance back surface 6 Rin dir Direct reflectance front surface 7 Rin aitt Diffuse reflectance front surface 8 Rb air Direct reflectance back surface 9 Rbn aitt Diffuse reflectance back surface 6 Copy the new columns to Notepad and create a text file as the one presented in Figure C 3 the characteristics of this file are in accordance with the models described on 17 C 2 Units Nanometers Manufacturer Saint Gobain Product name SGG Antelio silver Product type 1 Position 1 Material Glass pranto Clear Thickness conductivity Emissivity front 0 85 Emissivity back 0 85 300 320 340 360 006 252 477 499 551 563 ead 598 614 632 645 657 665 671 671 674 668 669 666 66 0 o 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 o 0 0 0
153. w the accomplishment of the standard indoor requirements without the use of mechanical cooling As it was expected when a solar control glass replaces the reference outer pane which was a low e coating glass Pilkington Optitherm SN4 the heating demand increases slightly The need for electrical lightning varies depending on how transparent to light the glass is When compared to the reference glazing the total energy demand for some solar control glasses combined with mechanical cooling can be reduced approximately to 2 3 Finally some combinations of solar control glasses with ordinary solar shading systems were simulated The best performances were achieved for 150 and 154 which result from the combination of a solar control glass body tinted and hard coating respectively with external venetian lamellas made of aluminium In these cases total energy demands of 11kWh m year and 14kWh m year were correspondingly obtained without the use of mechanical cooling To remove completely the hours of overheating above 22 C air conditioning system may be used and as a result the total energy demands increase to 15kWh m year and 17kWh m year respectively this is half of the energy consumption achieved with the reference glazing 6 4 2 Lisbon 6 4 2 1 The reference system Regarding the heating demand the situation for Lisbon is similar to Copenhagen The envelopment solutions are very good concerning the Portuguese climate low U values 0 4W
154. y maximum total energy consumption that an office building may have to be in accordance with the Danish building code and it is approximately 95kWh m for large office buildings A 2200m However for the nowadays purpose of saving energy a lower energy demand would be expected at least half of the standard limit The total energy consumption of a building E includes the energy for heating En cooling Ec lightning E mechanical ventilation Emy and hot water Enw According to 2 the energy demands for lightning and mechanical ventilation must be multiplied by the factor 2 5 since they refer to electrical energy The heating and cooling systems were assumed to be district systems and in this way the correspondent heating and cooling demand do not need to be affected by the factor 2 5 All the equipment efficiencies were considered equal to the unit E E E 25x E 2 5x Em Ey kWh m year 6 2 For the different solutions of solar shading systems only the energies for heating cooling and lightning vary and their values are calculated by BuildingCalc LightCalc The mechanical ventilation was set constant during the working hours and equal to the minimum required on the indoor environment standard 14 0 9h The energy demand for mechanical ventilation is given by x 8 airchange _ rate x Vx SEL i 1 kWh m year 6 3 A 5500 4 e 25xE 2 5 25 where nis the number of hours in which the required mechanical ven
155. ylight enters the room At the same time this electrical lightning demand contributes to the internal loads of the room On the other hand the way the shading system is activated is not yet very close to reality The shading system is activated when the indoor temperature is higher than the cooling setpoint This means that a shading system can be activated during overcast situations in which the indoor temperature is higher than the cooling setpoint In this way the natural light entering the room is less and the electrical lightning demand may be wrongly increased In this way the shading activation should also somehow depend on the luminance of the sky It would be also interesting to control the shading systems with respect to indoor daylight and glare Nowadays there is still a lack of data about the angular and spectral properties of the solar shading systems Manufactures rarely have this information available often thermal properties are not available and optical properties are given as integrated values instead of spectral values Some suggestions were given on how to make use of the available data from manufactures It seems that the use of simplified data for solar shading systems does not have a large influence on the final performance of buildings However only few cases were studied More research should be done on this area and for different types of solar shading systems 56 PART B GLASS LAMELLA SYSTEMS COMPARING MEASUREMENTS WITH
156. zen Product info Thermal properties Optical properties thickness 8 slat chord width w 500 YS crown height c 0 W ess ats Pe slat pitch p l 500 Eras pr ai E mA Leyak Z P an slat angle 90 degrees on PIA Slat orientation 1A SUA R Horizontal C Vertical Go to Glav_Stopray Silver_IPS lw Return Output Calculate Import from text file Record geg 126 PJPP of 340 Figure C 4 Geometric properties for the SGG Antelio Silver glass lamellas C 4 Appendix D Tips on how to import the glass lamellas to BuildingCalc LightCalc The way to import the text files generated from WIS to BuildingCalc LightCalc is approximately the same as described on APPENDIX 2 A 2 2 BuildingCalc LightCalc How to import the text files with the properties of the window generated in WIS Also for the glass lamellas different text files must be generated in WIS for different slats angles However when importing to BuildingCalc LightCalc the WIS text files the file that must be loaded for the clear glazing is not the glazing without shading but the glazing with the glass lamellas opened slat angle of 0 The reason for this is that the glass lamellas are not retractable After loading the files a correction must be made For the shading position gt no shading red square in Figure D 1 the properties must be reinserted manually and equal to shading position gt 0 red square in Figure D 2 The result must
157. zontal metallic profiles of the glass lamellas system On the other hand the results show that during measurements the referred measuring point was under the influence of direct light 85 14 Conclusions and further work Comparing measurements with simulations is always a delicate process even with the most highly developed software According to 5 Radiance is one of the most advanced daylightning lightning simulation tools available but anyway it can not represent perfectly the nature For instance the distribution of the sky is defined according to standard procedures which are of course not found in reality Also during measurements many uncontrolled factors may vary Daylight measurements in the experimental rooms of the Daylight Laboratory at SBi were compared with ESve Radiance simulations Four different cases for different sky conditions and lamellas orientation were studied lESve Radiance is a user friendly software and according to results it seems that it is valid when simulating the daylight performance of glass lamellas systems as a trans material under overcast sky and also under sunny sky if the lamellas are closed For simulations under sunny sky and with some lamellas opened it is advised to use the original version of Radiance to get more accurate results There are two experimental rooms also at DTU and one of them has already a glass lamellas system mounted on its fa ade The other will be the reference ro

PERFORMANCE EVALUATION OF SOLAR SHADING SYSTEMS

Contents

Download Pdf Manuals

Related Search

Related Contents