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Sun Angle Calculator

1. Sun Angle Calculator Sun Angle Calculator 37 58 North Latitude Sun above horizon aca Boren Min A Maneo Macnee Sun behind leafy trees From Apr 5 Until Oct 15 Y Ignore year 80 Sun through bare trees Date PY KWH M Graph Horizon loaded for Sample Horizon Aug 26 13 81 Open Horizon File 0 00 Bare trees reduce PV to 0 80 3 81 KW Elev 67 5 PV 75 Elev 45 0 PV 50 10 N Elev 22 5 PV 25 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 No of PV Panels HP S Watts per Panel 290 2 PV Max KW 4 06 Month and Day to Graph Ignore year PY Azimuth PY Tilt O AM E O AM 130 ma Aug26 Calculate for hours between Ey PM N Maximum Calculate 12 Months w2 E Delay ms Minimum S 12 day PY KWH 100 Copy Z Show Results Results in CSV 139 06 Calculate Best PV Alignment Sun on lt lt AUG 26 gt gt with horizon Sample Horizon PV azimuth 180 PV tilt 42 Calci atear Augusto 6am Azimuth 82 Elevation 6 PV power potential 0 00KW PV power actual 0 00 KW PV Azimuth PY Tilt 7am Azimuth 91 Elevation 18 PV power potential 0 09KW PV power actual 0 00 KW Eram To From To 8am Azimuth 101 Elevation 30 PV power potential 0 77KW PV power actual 0 77 KW 100 gt 260 s 20 30 gt 9am Azimuth 113 Elevation 41 PV power potential 1
2. 4 Elev 0 0 PV 0 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 No of PV Panels 14 5 watts per Panel 290 PV Max KW 4 06 Month and Day to Graph Ignore year PY Azimuth PY Tilt 163 ao N Maximum Calculate 12 Months Wa E N 12 day PV KWH Minimum s da 2 i Enon Calculate Best PV Alignment Sample Horizon Jan 4 14 PV panels 4 06 KW Best azimuth 175 Best tilt 20 Power 24 17 KWH IESE ASE Ua PCy Sample Horizon Feb 4 14 PV panels 4 06 KW Best azimuth 175 Best tilt 24 Power 26 95 KWH PV Azimuth PY Tilt Sample Horizon Mar 4 14 PV panels 4 06 KW Best azimuth 180 Best tilt 34 Power 25 74 KWH From To Fram To Sample Horizon Apr 4 14 PV panels 4 06 KW Best azimuth 145 Best tilt 40 Power 21 68 KWH 400 260 20 l 80 Sample Horizon May 4 14 PV panels 4 06 KW Best azimuth 150 Best tilt 56 Power 15 48 KWH Me A xA Sample Horizon Jun 4 14 PV panels 4 06 KW Best azimuth 145 Best tilt 60 Power 13 96 KWH Month BestAz Best Tilt KWH Sample Horizon Jul 4 14 PV panels 4 06 KW Best azimuth 145 Best tilt 62 Power 13 92 KWH Avg 163 40 24 14 Sample Horizon Aug 4 14 PV panels 4 06 KW Best azimuth 150 Best tilt 56 Power 15 33 KWH a n Sample Horizon Sep 4 14 PV panels 4 06 KW Best azimuth 165 Bes
3. 75 of maximum PV power with horizon 22 70 KWH 82 of no horizon and 62 of maximum SUMMARY For azimuth 180 and tilt 42 During the 12 one day periods the PV panel is illuminated for 128 hours Maximum possible PV power 519 68 KWH PV power no horizon 268 51 KWH 52 of maximum PV power with horizon 243 96 KWH 91 of no horizon and 47 of maximum Figure 11 Calculation summary Oe Veet veer The summary shows The number of hours the PV array was illuminated during the 12 days calculated Remember each month s calculation is for one specific day in that month not for the entire month so the total hours are only for those 12 days not a full 365 days The maximum power that the PV array would produce if the sun were shining dirsectly on it the entire time In other words this is the value shown in the PV Max KW field multiplied by the total illumination hours The power that would be produced with a clear horizon with the PV array at the specified azimuth and tilt along with the percentage of maximum possible power 52 in Figure 11 The power that would be produced with the actual horizon loaded into SAC with the PV array at the specified azimuth and tilt along with the percentage of clear horizon power and maximum possible power and 91 and 47 in Figure 11 Sun Angle Calculator User Manual Page 11 CSV calculation report You can tell SAC to produce the cal
4. a compass to determine the azimuth bearing but be sure to subtract the magnetic declination from the compass reading to get true north Magnetic declination is the difference between true north and magnetic north and varies by geographical location You can find the magnetic declination for your location by entering your ZIP code on this Web page http www ngdc noaa gov geomag web id declinationFormld then clicking Get Location followed by Calculate If your declination is positive then magnetic north is east of true north so you should subtract that number of degrees from the desired bearing For example if your declination is 5 and you want to find true east 90 the true azimuth relative to magnetic north on the compass would be 85 90 5 85 If your declination is negative then magnetic north is west of true north so you should add that number of degrees to the desired bearing For example if your declination is 5 and you want to find true east the true azimuth relative to magnetic north on the compass would be 95 90 5 95 Print the table on the next page Take elevation sightings every five degrees of true azimuth and enter the elevations in the table Sun Angle Calculator User Manual Page 3 Horizon data table True Azimuth Elevation True Azimuth Elevation True Azimuth Elevation 80 150 220 85 155 225 90 160 230 95 165 235 10
5. close SAC When you start again the PV azimuth and tilt should be as you left them The settings that are preserved are gt gt gt gt Latitude Horizon file Bare tree PV reduction factor screen upper right Dates trees have leaves screen upper right Number of PV panels and watts per panel screen center PV azimuth and tilt screen right Calculation hours screen center Twelve month calculation delay screen center Calculate best PV alignment azimuth and tilt ranges screen lower right Summary SAC calculates hourly sun positions and PV power output for specific months and days using a PV alignment that you specify It can calculate the best PV alignment for a given month and day All calculations include the effects of shadows cast by the local horizon and also consider whether the shadows are cast by leafy trees full shade or cast by bare trees Here is a summary of how to use SAC gt gt gt gt gt o Define your horizon page 2 Start SAC page 5 Load your horizon page 6 Set the dates that trees have leaves page 10 Set a PV azimuth and tilt page 6 Choose a month to graph page 7 Decide if you want to save results to a file and name the file page 12 Run a calculation page 8 Analyze the hourly calculation report page 10 Produce reports in CSV if you want to load them into a spreadsheet page 12 Animate the graph and p
6. you want to run the program Defining Your Horizon The first step in using SAC is to define your local horizon trees or buildings that might obscure the sun at times during the day A horizon file is a text file that can be created and edited with a text editor like Notepad Each line contains an azimuth number degrees from true north a comma and an elevation number that represents the top of any obstruction in that direction For example these three lines show the top of obstructions at three azimuths 90 95 and 100 90 40 95 35 100 25 At 90 due east the top of the obstruction is 40 high At 95 it drops to 35 and at 100 10 south of due east it drops further to 25 Two horizon files are included with SAC One horizon sample csv contains a simulated horizon from azimuth 80 through 280 The other horizon clear csv contains a clear horizon no obstructions through the same azimuth range Gather the horizon data The first step is to record elevation measurements at various azimuth bearings around your PV array One way to do this is to mount a level on a camera tripod sight toward the top of obstructions and read the degrees of elevation from the level Electronic levels work well but you also can use a small liquid filled level with a floating pointer and degree markings on the side of the case such as the one shown in Figure 1 Sun Angle Calculator User Manual Page 2 Use
7. 0 170 240 105 175 245 110 180 250 115 185 255 120 190 260 125 195 265 130 200 270 135 205 275 140 210 280 145 215 285 Transfer the data to a horizon file Once you have collected your horizon data transfer it to a CSV horizon file The best way to do this is to open the horizon clear csv file included with SAC in Notepad or other text editor not a word processor Immediately save the file with a different name such as Front Yard Horizon csv and replace the zero elevations with your readings Note The first line of the horizon file must contain the name you wish to assign to the horizon e g Front Yard This name will appear on SAC s screen when the horizon is loaded The first horizon azimuth and elevation entry appears on the second line of the file If the file contains azimuth bearings beyond your readings e g 80 85 275 280 delete those lines Save the file when you are done entering your data Sun Angle Calculator User Manual Page 4 you created on the computer s desktop You will be presented with this screen Using SAC strongly urge you to go through this section and perform every step When done you will understand what each control does plus how SAC calculates and presents its results Please note that your calculated results will vary from those in the illustrations unless you set the same latitude load the same horizon file set the same month and day and set the same PV
8. 57KW PV power actual 0 00 KW x XA A x 10am Azimuth 128 Elevation 51 PV power potential 2 48KW PV power actual 2 48 KW Month BestAz BestTilt KWH 11am Azimuth 150 Elevation 59 PV power potential 3 38KW PV power actual 3 38 KW 12 00 Azimuth 180 Elevation 62 PV power potential 3 81KW PV power actual 3 81 KW 1pm Azimuth 210 Elevation 59 PV power potential 3 38KW PV power actual 3 38 KW 2pm Azimuth 232 Elevation 51 PV power potential 2 48KW PV power actual 0 00 KW 3pm Azimuth 247 Elevation 41 PV power potential 1 57KW PV power actual 0 00 KW TT eT Pe nT Om O Save Results to File aati eis om o ee ore eer Pa User Manual by Mike Dodd mike mdodd com November 17 2012 This manual and the software are copyright 2012 Michael M Dodd All rights reserved Table of Contents DEVO CUCTI ON riia ea aa ATAA wt cas cesz uscd hath A R A A E 1 FO AtureS acena eth So partion tne A erates i A en 1 Instala tioN eaa stsccdeces sec encase ences tegvesacsbstuncteczusziaccunsexe tasccie a a a a 2 Install the Net tram works ssori aeaa anaana aiaa kania aa aE ANa aAA EAEAN ANEA aaea iaaa 2 Extract the SAC HOS acan S A TANE AE T A 2 Defining Your HoriZ N sarkai a a aeaaea a iana taada adianta aa Mads eden east eee eee 2 Gather the horizon Gitanes ARENA AE A AA ENN NEA EAS 2 Horizon data ADIE certana helo AE AA AAAS A TAR A acer dk MO ce cae 4 Transfer the dat
9. Enter key Delays are in milliseconds 1 1000 of a second from 100ms 0 1 second to 3000ms 3 seconds Play around with this to find a comfortable viewing time or to zip quickly through all 12 months During the 12 month calculation SAC produces a summary report with one line for each month Sun Angle Calculator User Manual Page 13 F Maximum CO Save Results to File Calculate 12 Months 25 29 KWH Oct 21 12 day PV KWH Delay ms Minimum Sample Horizon Jan 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 24 18 KWH Sample Horizon Feb 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 25 13 KWH Sample Horizon Mar 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 23 55 KWH Sample Horizon Apr 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 14 67 KWH Sample Horizon May 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 11 36 KWH Sample Horizon Jun 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 11 39 KWH Sample Horizon Jul 21 14 PV panels 4 06 KW Azimuth 180 tilt 42 Power 11 40 KWH Camnle Unarivgan Arna 94 4A _ D nanala ANG LKAN Asimiith 10 tilt AD Dawar 1A 02 KWL Figure 15 12 month calculation report Each line in the 12 month calculation summary report shows the horizon loaded the date the number of PV panels and their maximum power the specified PV azimuth and tilt and the power produced In addit
10. PV output power position relative to your local horizon on a specified day of 12 months and produces a detailed report This report may be copied and pasted into a word processing program for detailed analysis You may tell SAC to produce the report in comma separated value CSV format for loading into a spreadsheet Reduces available PV power when the sun is shining through bare branches or is obscured completely by leaves User specified PV characteristics number of panels watts per panel as well as adjustable azimuth and tilt Calculates the optimum PV azimuth and tilt for one month or all 12 months Northern hemisphere only Sun Angle Calculator User Manual Page 1 Installation Install the Net framework You must have the Microsoft Net Framework 4 Client Profile installed on the computer on which you wish to run SAC If the framework is not already installed you can download or install it from this page http www microsoft com net download Extract the SAC files To install Sun Angle Calculator create a directory named Sun Angle Calculator on your hard drive then unzip all the files in the distribution Zip file into that directory You should see a file named Sun Angle exe the two CSV horizon files and this user manual To launch SAC double click Sun Angle exe For convenience create a shortcut to Sun Angle exe on your desktop so you don t have to navigate to the Sun Angle Calculator folder each time
11. PV tilt 42 calcate for Marchen 7am Azimuth 99 Elevation 12 PV power potential 0 57KW PV power actual 0 45 KW 8am Azimuth 109 Elevation 23 PV power potential 1 28KW PV power actual 1 02 KW 9am Azimuth 121 Elevation 34 PV power potential 2 09KW PV power actual 1 68 KW 10am Azimuth 137 Elevation 43 PV power potential 2 95KW PV power actual 2 95 KW 11am Azimuth 156 Elevation 50 PV power potential 3 68KW PV power actual 3 68 KW 12 00 Azimuth 180 Elevation 52 PV power potential 3 99KW PV power actual 3 99 KW 1pm Azimuth 204 Elevation 50 PV power potential 3 68KW PV power actual 3 68 KW 2pm Azimuth 223 Elevation 43 PV power potential 2 95KW PV power actual 2 95 KW 3pm Azimuth 239 Elevation 34 PV power potential 2 09KW PV power actual 1 68 KW Go stop 4pm Azimuth 251 Elevation 23 PV power potential 1 28KW PV power actual 1 02 KW ttl Aa a a kat ris a i a am aizin Save Results to File PY Azimuth PY Tilt From To From To 100 gt 260 gt 20 gt 80 gt Month BestAz BestTilt KWH Figure 7 First calculation results The PV power for each hour is shown as a vertical green bar with the total output in kilowatts KW at the top of each line The PV legends at the left show that the horizontal green lines represent zero 25 50 75 and 100 top of the PV s maximum possible power PV power varies base
12. a calculation at any time Let s do so now to see how this works To begin familiarize yourself with several related controls PV azimuth and tilt controls Notice the PV azimuth and tilt controls on the right side of the screen Sun Angle Calculator User Manual Page 6 PV Azimuth PY Tilt 180 LEE Figure 4 PV azimuth and tilt controls When SAC starts these are set to 180 azimuth due south and 42 tilt Tilt is measured in degrees leaning backward from vertical In other words if the PV panel is standing vertical and looking horizontally toward the horizon the tilt is zero degrees If you lean the panel backward 20 so it is looking slightly upward you should set the PV Tilt control to 20 You may change a value using an up down arrow or by typing in a new value and pressing the Enter key each click of an azimuth arrow changes the value by five degrees Each click of a tilt arrow changes the value by two degrees Whenever a value changes the diagram beneath it changes to depict the new PV orientation PV characteristics To the left of the PV azimuth and tilt controls you ll find two green fields where you can enter information about your PV array No of PV Panels 14 Watts per Panel 290 j PY Max KW 4 06 Figure 5 PV characteristics controls Use the up down arrows or type in a value to tell SAC how many PV panels you have and how many watts each panel produces in f
13. a to a horizon TIIC ssccssssssssssessesssssessensoesensersoessensoessessessoessessoeseesseusoessessorsoesseoesseeeesseessseessaes 4 Using SAC asiana A R AN ee eed a E N ee a aa 5 Enter your latitude orroa ar AEE AEEA ENET ONN EED EETA A NEEESE AEE EE E 6 Load Your Horizons anea See aaa vel neice caren eee eas ental terse EN lea 6 Caml CU enti Svcs ccc tee sa cccnci eae E Ea EAR ceduesBexsescutenselb avec succclvute AA AAE AERE ENN 6 PV AZIMUTH and tilt controls saoga EEANN EESAN aAA PEAN orane ANNEN ENa ANE NARRASA REEE 6 PV Characteristics oeie ainina baceefeedviceuacocanssnecedeexbvees sos aud eedlacbce eves sasaouenesuenseueutsasuesoennendh desvbveesirenceeeoets 7 Month and day to graph CONtIOIS cccceccsccesecseeseeeeeeeesaeeseeeeseeeeaeeeeesaesneeeaenaeseesnaesaeseessaesnesneesaeseessaeeeseesesanensaeenses 7 RUN the Cal CULATION oisean anera a EA EAEE A EEEN AEA EEAO A ETAR VAA EA aA E ES 8 The calculation grapes chested a ee eh Aina iad ent la eda 8 All times are sun UMES acean eieaa aan na Satan ENERE Ea AOA dense ened e edeseeiees lead ANER 8 Reducing PV power behind bare trees cccsccsscsssssecseeesceeeeeeseaeeseeseesaeeseseeeeaeseeseeeeaesneesaeeeeseaeseeseeneesneeneeeenneeeeas 9 No PV power behind leafy trees ssscssssscesssseseesseessesssssseneesesesseseesseenoesessneesoesseenseseesnoeseesessneesseesnsonsnseesnasesnees 9 Setting the dates that trees have lAVES sccscssesceseseeeseeseees
14. board then launch your favorite text editor or word processor and paste the report into it for easier reading Or you can save the results directly to a file as described in Saving the results to a file on page 12 What is PV potential power vs PV actual power Notice that each line in the report contains figures for PV potential and actual power The potential power is the amount of power the PV array would generate if it were in full sun at that hour This is determined by the PV array s maximum possible power scaled by the its azimuth and tilt relative to the sun s position The actual power is the amount of power the PV array will generate at that hour behind your horizon You can see this easily by loading the sample clear horizon horizon clear csv Without obstructions the PV s actual power in each hour is equal to its potential power Furthermore if you set the PV azimuth to 180 and the tilt to the sun elevation listed for 12 00 and then recalculate you ll see that the PV s potential and actual power are the same as its maximum power at noon on that month and day This is because at noon the PV array now is pointing directly toward the sun and there are no horizon obstructions The calculation report summary SAC includes a summary at the end of the calculation report C Save Results to File 100 bam Delay ms Minimum 12 day PV KWH Eaa mannna po s PV power no horizon 27 54 KWH
15. characteristics shown in those illustrations Launch SAC by double clicking on Sun Angle exe in the Sun Angle Calculator folder or on the shortcut Sun Angle Calculator 37 58 North Latitude Open Horizon File Graph Horizon loaded for Horizon Min Az Horizon Max Az Sun above horizon Sun behind leafy trees I From Apr 5 Sun through bare trees B Date PY KWH i Until Oct 15 ignore year Save Results to File ca Month and Day to Graph Ignore year Sep 5 Calculate for hours between Show Results No of PV Panels 1 Watts per Panel 290 PV Max KW 5 OM TE O AM OPM OPM 12 day PV KWH Calculate 12 Months Delay ms w0 Maximum Minimum Figure 2 Opening screen PY Azimuth 1380 PV Tilt 2 N yE S Calculate Best PV PY Azimuth ae mp 1220 Ie Month BestAz BestTilt KWH Calculate for September only N Alignment PV Tilt _From To tae 2 Go Take a moment to become familiar with this screen SAC presents information in white fields You enter your information in green fields except for the three date fields that display calendars when clicked these fields cannot be colored green The upper portion is where you enter your location information including north latitude horizon and the dates
16. culation report in CSV format which can be loaded into most spreadsheets Check the Results in CSV box and run the calculation again Notice that the report now looks like this With the exception of the first line each line contains values separated by commas bau O Save Results to File Minimum 12 day PV KWH Show Results Results in CSV 245 17 Sun angles for latitude 38 Maximum PV power is 4 06 KW 2 Date Hour Azimuth Elevation Max PV KW Derated PV KW Jan 21 8 125 9 2 74 2 19 Jan 21 9 136 18 3 36 2 69 Jan 21 10 149 26 3 81 3 81 Jan 21 11 164 31 3 99 3 99 Jan 21 12 180 32 3 82 3 05 Jan 21 13 196 31 3 29 3 29 Jan 21 14 211 26 2 55 2 04 Jan 21 15 224 18 1 74 1 39 Jan 21 16 235 9 0 98 0 79 v Wann ran Ara Figure 12 CSV calculation report The first line is the report title and will appear in the first row and column of a spreadsheet If you don t want this delete it in the spreadsheet The second line contains column headers separated by commas These often are helpful in a spreadsheet to identify the contents of each column Each of the remaining lines contains values for Date The month and day of the calculation Hour The hour of the calculation Azimuth The sun s azimuth Elevation The sun s elevation Max PV KW The maximum PV power in kilowatts for the specified PV azimuth and tilt and the sun s position i e this is the clear horizon power Derated PV KW The ac
17. d on its azimuth and tilt relative to the sun s azimuth and elevation SAC calculates this for each hour If you would like to see this effect load the sample clear horizon file horizon clear csv and calculate again Now the unobstructed PV s hourly power varies solely due to its orientation relative to the sun s position in that hour Reducing PV power behind bare trees Even if the sun is below the horizon of bare leafless trees Figure 7 much sunlight will shine through the branches But those branches cast shadows so PV power must be reduced to the factor specified by the Bare trees reduce PV to control This factors in the shadows cast by the tree trunks and limbs these shadows are not full shade so the PV sill produces significant power The default value of 0 80 means that when leafless tree shadows fall on it the PV will produce 80 of the power it produces when it is in full sun relative to the sun s position in the sky of course It does not mean that the PV output is reduced by 80 It is reduced to 80 Set this to a value that makes sense for our location and type and quantity of trees If you have evergreen trees that cast shadows year round set this to zero No PV power behind leafy trees Ifthe sun is below a horizon of leafy trees Figure 8 SAC assumes that the shaded PV array produces no power so no vertical lines appear for those hours Sun Angle Calculator User Manual Page 9 Setting the dates t
18. day PV KWH Show Results Results in CSV 226 01 Figure 13 Save to file controls Now when you click the Calculate button the Calculate 12 Months button page 13 or the find best Go button page 14 SAC writes the calculation results to your file as well as displaying them in the results window Each set of results is preceded with a header line beginning and ending with 10 dashes such as CALCULATE BEST PV ALIGNMENT This heading occurs in CSV files as well as regular text files so it will appear in the first column of a spreadsheet when the CSV file is loaded You can delete that row or keep it as you choose Calculating for an entire year Sometimes it s interesting to visualize sun positions and PV power month by month SAC allows you to do this with the 12 month calculation controls When you click the Calculate 12 Months button SAC performs exactly the same calculations as when you click the Calculate button but instead of graphing only one month it graphs each month as it calculates Maximum Calculate 12 Months Delay ms Minimum 100 gt Figure 14 Calculate 12 months controls Since the month graphs all appear one by one in the same area it helps to slow the process to allow time to view each graph The Delay ms control allows you to specify a delay following each graph Set this delay using the up down arrow or by typing in a new value and pressing the
19. eeeeeseessesseesaeeseeseeseenseeseesaesseesaeseeeseesennsensanesneess 10 The calculation re portiiccscieesikoiieiedete ks hice elie ei ao Sabena allan Side eae alee olde 10 The calculation report SUIMIMALY cs ecsssssssssessssssessenseessensersoessensoessesseesoessesserseessensoessessoesoessensoeseessenseensensees 11 CSV calculation reporton eadar italiane viele ei en nian ies 12 Clearing the calculation report sscscsssssesssrssensessssssessessoessesseessessensoessensoesoesoessoeseenseusoeseesnsoesssoessueesseenseees 12 Savin the results to a Terracina AN AAAS ccescsnedeves Hibbavs laste AANE AEAEE EAT 12 Calculating for an entire YOal sccsccssssessesssessesescssessessersessessoessesseescessessessoessesseensenseesoensenseeseesaesseesscessoesseees 13 Finding the best PV aliSMMeniteccscesiciccs cdeccecdecscehevtacdacssavcsteSeseaceudeededbes hacnci cutee tevsesdeneceadesceasucnunreyeuceudewudceesueeesievesubenste 14 Saving YOUN SOUti in Seeria anaE NA e A TE AEEA E A AANE AEE e T E 16 SALANT Y EEE E E A E E O A E E cae 17 Introduction Welcome to the Sun Angle Calculator SAC This manual explains how to use the program to plan a photovoltaic PV solar power array for your specific location and site horizon trees and other obstructions Features SAC offers these features Graphs hourly sun position relative to your local horizon on a specified day of a specified month Calculates hourly sun position and
20. erform calculations for 12 months using a particular PV alignment then analyze the summary report page 13 Find the best PV alignment for one or 12 dates then analyze the summary report page 14 If you find the average best PV alignment helpful animate the graph and perform calculations for 12 months using that azimuth and tilt then analyze the summary report page 13 Sun Angle Calculator User Manual Page 17
21. files provided with SAC then click the Open button on the file dialog The horizon graph and other information from the file should appear plus the results from an initial sun angle and PV power calculation such as this from horizon sample csv Sun Angle Calculator 37 58 North Latitude Sun above horizon Monzon Mn AS Boreo ME AS Sun behind leafy trees From Apr 5 Until Oct 15 Ignore year 80 280 Sun through bare trees Date PY KWH Horizon loaded for Sample Horizon Mar 21 23 55 Open Horizon File EV 0 00 080 v Graph 3 99 KW 3 68 KW Elev 67 5 PV 75 Elev 45 0 PV 50 T Ere 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 Figure 3 Horizon loaded Notice that the name of the horizon from the first line of the CSV file appears above the graph Also the minimum and maximum azimuths from the file are shown and the graph encompasses this range The graph displays the azimuth degrees along the bottom with four horizontal green lines for elevations between zero and 67 5 degrees 90 is at the very top of the graph The horizon is represented by the blue line Calculating SAC automatically calculates the hourly sun position and PV output power when the horizon is loaded producing an initial set of results But you can run
22. hat trees have leaves For accurate PV power calculation you should specify the dates that trees in your area have leaves casting full shadows In the upper right corner of the screen are two controls to set these dates Click the arrow on a control and a calendar appears Ignore the year Sun above horizon Sun behind leafy trees I From Apr 5 Until Oct 15 Sun through bare trees Leafy t April 2012 Date PV KWH a ies 23 55 Ignore year Sun Mon Tue Wed Thu Fri 1 2 3 4 Be 7 8 9 0 1 213 14 15 1 17 18 19 20 21 22 eo ete D eo ee Mar 21 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 Figure 9 Leafy tree calendar control Use the left and right arrows to select a month then click on a day The calendar disappears and the date appears in the white field above it Set the From date to the month and day when trees have most of their leaves even if not fully developed Set the To date to the month and day when trees have dropped most of their leaves leaving only bare branches The calculation report Even though only one month is graphed SAC performs the same hourly calculations for the specified day in all 12 months so a lot of data is created The results of these calculations are displayed in the white window at the bottom of the screen but you have to scroll to see them all After a calculation SAC scrolls the results to the month being graphed scroll u
23. ion the minimum and maximum power for each month is captured during the calculations At the end these values and the dates on which the occurred are displayed to the right of the Calculate 12 Months button Figure 15 If the Results in CSV box is checked the summary is produced in CSV format as described on page 12 Finding the best PV alignment SAC can automatically perform its calculations for every PV azimuth and tilt within a specified range and capture the best orientation Here s how to use this feature Locate the Calculate Best PV Alignment controls in the lower right corner of the screen beneath the PV azimuth and tilt controls Figure 16 Be sure a horizon is loaded as described in Load your horizon Use the up down arrows on the green From and To controls to specify the desired azimuth and tilt range or type new values and press the Enter key As with the regular PV controls azimuth changes in 5 increments and tilt changes in 2 increments If you want to find the best PV alignment for just the currently selected month check the Calculate for month only box This caption changes whenever you change the month and day to graph with the Month and Day to Graph control on the left of the screen If this box is unchecked SAC will calculate for all 12 months and average the results Sun Angle Calculator User Manual Page 14 PY Azimuth PY Tilt 180 a N weg S Calculate Best PV Alignment C Calcu
24. late for August only PY Azimuth PY Tilt From To From To DA CDA DAVE Month Best Az Best Tilt KWH Figure 16 Find best controls Click the Go button and watch the PV azimuth and tilt controls and the horizon graph SAC positions the PV to each azimuth in the specified range 5 increments then sets the tilt to each position in its range 2 increments and performs the calculation Results At the end of the complete azimuth and tilt ranges SAC sets the PV alignment to the azimuth and tilt that produced maximum power and graphs the sun and PV power for that day and month SAC also produces a one line summary showing the date PV information azimuth and tilt and PV power for that date 12 month calculation If you elected to calculate every month SAC first calculates for January rewinds the azimuth then immediately sets the PV alignment to the newly calculated azimuth and tilt that produced maximum power and graphs the result After a brief pause SAC repeats the calculation for each successive month A one line summary for each month is added to the summary report as shown in Figure 17 At the end of the 12 month calculation SAC sets the PV alignment to the average of the 12 azimuths and tilts that produced maximum power in each month and graphs the sun and PV power for the specified day in December the final month in the search Note This average alignment may or may not be helpful It is dis
25. p or down to see other months a O Save Results to File Delay ms Minimum 12 day PV KWH Ga Show Results Results in CSV 243 96 z l Sun angles for latitude 38 Maximum PV power is 4 06 KW amp Sun on lt lt JAN 21 gt gt with horizon Sample Horizon PV azimuth 180 PV tilt 42 8am Azimuth 125 Elevation 9 PV power potential 1 94KW PV power actual 1 55 KW 9am Azimuth 136 Elevation 18 PV power potential 2 66KW PV power actual 2 13 KW 10am Azimuth 149 Elevation 26 PV power potential 3 33KW PV power actual 3 33 KW 11am Azimuth 164 Elevation 31 PV power potential 3 82KW PV power actual 3 82 KW 12 00 Azimuth 180 Elevation 32 PV power potential 4 00KW PV power actual 3 20 KW ipm Azimuth 196 Elevation 31 PV power potential 3 82KW PV power actual 3 82 KW 2pm Azimuth 211 Elevation 26 PV power potential 3 33KW PV power actual 2 66 KW 3pm Azimuth 224 Elevation 18 PV power potential 2 66KW PV power actual 2 13 KW 4pm Azimuth 235 Elevation 9 PV power potential 1 94KW PV power actual 1 55 KW nS SEEN eT a or a er a A Figure 10 First calculation report Figure 10 shows only the first few hours for January 21 Use the scroll bar to browse through the remainder of the report Look for the remaining hours in January then all hours in the subsequent Sun Angle Calculator User Manual Page 10 11 months Better still click the Copy button to copy the entire report into the Windows clip
26. played instead of the December alignment to reduce confusion At minimum it is a good starting alignment to calculate for all 12 months using the Calculate 12 Months button as described on page 13 Click the red Stop button to interrupt a best alignment calculation Click it a second time if the first click does not stop the process Note If you interrupt the find best calculation with the Stop button the PV azimuth and tilt controls are likely to be in wildly different positions than they were at the start Be sure to restore them to correct values or subsequent calculations with the Calculate or Calculate 12 Months button will produce strange results Sun Angle Calculator User Manual Page 15 Here is SAC s screen after running Calculate Best PV Alignment for 12 months using the sample horizon and the default control values found on the opening screen but with the Day of Month set to the 5th instead of the current date Notice that the December radio button is marked since that was the final month in the calculations Notice the results described above Sun Angle Calculator 37 58 North Latitude Sun above horizon HOn Minted Hencont Mieke aos Sun behind leafy trees a From Apr 5 Until Oct 15 Ignore year Open Horizon File 80 280 Sun through bare trees E Date PY KWH Graph Horizon loaded for Sample Horizon Elev 67 5 PV 75 _ Elev 45 0 PV 50 ee Elev 22 5 z 25 SS
27. re 7 the March 21 calculation date is before the April 5 leafy trees date so trees have no leaves and the sun is colored orange below the horizon In Figure 8 the leafy trees date has been changed to March 5 so the March 21 calculation date is after that date Now trees have leaves and the sun is colored reddish brown below the horizon Sun Angle Calculator User Manual Page 8 Sun Angle Calculator 37 58 North Latitude Sun above horizon TE Ponzo Mias As HorioniMaxcA Sun behind leafy trees I From Apr 5 Until Oct 15 Y Ignore year Open Horizon File 80 Sun through bare trees Date PY KWH Graph Horizon loaded for Sample Horizon Mar 21 23 55 J 0 00 0 80 3 99 KW Elev 67 5 PV 75 Elev 45 0 PV 50 Elev 0 0 PV 0 Tos i Koss KW 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 No of PV Panels a Watts per Panel 290 PY Max KW 4 06 Month and Day to Graph Ignore year PY Azimuth PY Tilt gt oo 180 42 s Mar21 Calculate for hours between 5 AM 7 i Stait ie Tae CEM ee N Maximum Calculate 12 Months yE Delay ms Minimum s 12 day PV KWH 100 Copy 7 Show Results Results in CSV 243 96 100 Calculate Best PV Alignment Sun on lt lt MAR 21 gt gt with horizon Sample Horizon PV azimuth 180
28. t tilt 52 Power 14 23 KWH Sample Horizon Oct 4 14 PV panels 4 06 KW Best azimuth 180 Best tilt 42 Power 17 88 KWH Sample Horizon Nov 4 14 PV panels 4 06 KW Best azimuth 175 Best tilt 24 Power 26 92 KWH C se nett o ame MaL AA ma at O PM Sep 4 Calculate for hours between Li pa AM K 2 OAM oe EM Save Results to File Delay ms Figure 17 12 month find best PV alignment calculation results The average Avg best azimuth and tilt are displayed above the buttons and the PV azimuth and tilt controls are set to these values The report summary contains a line for each month showing the best azimuth and tilt for that date plus the PV power output The graph shows only the horizon to avoid confusion by showing December s calculation At this point you can click the Calculate 12 Months button to use the average best PV alignment to see how it performs for each month Or click Calculate to graph the results for one month at the average best alignment Saving your Settings Once you enter settings in SAC e g number of PV panels dates trees are leafy it is convenient for those same settings to be there each time you start the program SAC saves them automatically Sun Angle Calculator User Manual Page 16 when it closes To try this change for example the PV azimuth and tilt then
29. trees have leaves that create full shade The large gray rectangle is where your horizon the sun s path and PV power are graphed Below the graph are controls to specify when to calculate the sun s positions including month and day and from and to times When SAC opens the Month and Day to Graph control is set to the current month and day ignore the year Below the graph area are controls and fields where you tell SAC about your PV array including the number of panels watts per panel azimuth and tilt Sun Angle Calculator User Manual Page 5 The white window at the bottom is where SAC reports the results of a sun position PV power calculation Inthe lower right corner of the screen is a group of controls to command SAC to find the optimum PV azimuth and tilt for one month or an average for all 12 months and report the results Note Each time you close SAC it saves the current settings of most controls so the opening screen will not match Figure 2 after you make changes See Saving your Settings on page 16 for details Enter your latitude Enter your location s north latitude in green field located in the upper left corner of the screen Use degrees and fractional degrees not degrees minutes and seconds e g 37 50 not 37 30 00 Load your horizon Click the Open Horizon File button to open a file dialog then choose the CSV file with your horizon or one of the two sample
30. tual PV power in kilowatts for the specified PV azimuth and tilt and the sun s position behind the loaded horizon This number encompasses bare trees and leafy trees as described earlier Clearing the calculation report Click the Clear button to erase the contents of the calculation report and other fields This usually isn t necessary because SAC clears these at the start of each calculation Saving the results to a file You may save calculation results to a file either as regular text or in CSV format ready to load into a spreadsheet Here is how to do this Check the Results in CSV box if you want a CSV file Leave this box unchecked if you want a regular text file Check the Save Results to File box to open a file dialog If you chose to save in CSV format Sun Angle Calculator User Manual Page 12 you will see all files ending in csv and SAC will end your file name with csv Otherwise the file name will end with txt Type a new file name or select one of the existing files to write over it You do not need to add the csv or txt SAC does that for you CAUTION Do not write over the horizon files Note If you change the Results in CSV box after naming a file SAC does not change the file name to match You get the format you specified before naming the file Here is an example of the Save Results to File box checked and the file name entered Save Results to File C ternp SAC Results Day 21 txt 12
31. ull sun Each time a value changes the total maximum PV power in kilowatts KW is displayed in the adjacent white field Month and day to graph controls In the center of the screen you will find controls that tell SAC which month and day you want to graph and the daylight hours you re interested in seeing No of PY F 2 5 6 7 B Wee 183 14 15 16 17 18 19 20 21 22 ME 24 25 26 27 28 PV power potential 9am Azimuth 137 Elevation 16 PV power potentia Figure 6 Month and day to graph control Sun Angle Calculator User Manual Page 7 Click the arrow on the small rectangle that displays a month and day and a calendar appears Ignore the year Use the left and right arrows at the top to select a month Click on a day to select it and the calendar disappears If a horizon has been loaded when the calendar disappears SAC begins a calculation just as if you had clicked the Calculate button The selected month and day apply to the selected month s graph which shows one day in one month and also to the calculations for the same day in all 12 months In other words each time you click the Calculate button SAC calculates for the specified day in all 12 months but graphs the results for that day only in the selected month Select the daylight hours you re interested in calculating by entering the AM and PM hours in the green Calculate for hours between controls to the right of the Month and Da
32. y control Note When SAC starts the Month and Day control is set to the current day making it convenient to calculate sun positions and PV power for today Run the calculation Click the Calculate button If you loaded the sample horizon and left all of the controls with their initial values but set the Month to Graph and Day of Month controls to March 21 you should see the results shown in Figure 7 The calculation graph This is SAC s graph showing the sun angle and PV power output for each hour of the day using the initial settings and the sample horizon but changing the month and day to March 21 Notice the following The sun s position is shown for each hour on March 21 All times are sun times SAC considers all times and hours to be sun time which correlates to local standard time not daylight saving time If your locale observes daylight saving time the hours graphed and reported will be off by one hour This is irrelevant to PV power production because the sun s position in the sky is independent of daylight saving time However you might want to keep this in mind if you want to relate PV power to our daily schedule while daylight saving time is in effect Ifthe sun is above your horizon it is colored yellow If it is below your horizon it is colored orange Except If the sun is below your horizon on a date after leaves appear it is colored reddish brown Compare Figure 7 with Figure 8 In Figu

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