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Biomass Final_Report 2012

1. H 64 Table 7 Technical Specifications with the wanted value and the actual tested value 70 Table 8 Full Customer Requirements Table 76 Table 9 Cost benefit analysis te re a EC ED Eve P ERE HEU o E ERR ens 90 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 Overall Expense Reactor End Cap Matrix Glass Envelope Reactor Insert Removal Method Matrix Reactor Insert Matrix Reflector Material Matrix List of heat fluxes in Receiver Assembly 7 Revision History Version Date Name Reason for Changes 1 0 5 15 2012 TS Initial document 1 5 5 16 2012 PC Additions Revisions and Review with Casey Goodwin 2 0 5 19 2012 PC Final Report 8 Page Terms and Abbreviations The following terms and abbreviations are used extensively throughout this report and are described here for the reader e NCIIA National Collegiate Inventors and Innovators Alliance CAD Computer Aided Design e CSP Concentrated Solar Power e Torrefaction i e torrefy Torrefaction French for roasting of biomass e g w
2. 90 Appendix Expense Report uav a aet a etr ee a Pte e a er e 91 Appendix Er Decision 5 92 Appendix 6 Thermal Analyses Shining ii ase e eria a a airina 102 Appendix Reflector analysis eritar L a Zn ataei a w eaaa Su ua ays ia 108 Appendix Energy Calculations 120 Appendix J Torque Calculations 121 Appendix Ke CAD SeCtiOnl aaa u EN DR p ei 122 4 Page List of Figures Figure 1 A Ghanaian farmer watching dry brush and agricultural waste burn 10 Figure 2 Solar Biomass Reactor Spring 2012 11 Figure 3 Spring 2012 Prototype iirde eee edt 11 Figure 4 Device Prototype Summer 2011 l 16 Figure 5 CAD Model of Proposed Device Fall 2011 16 Figure 6 Possible solar dehydrator design deemed 18 Figure 7 Toyola stove Image found at http www unep org unite 30ways viewimage aspx projectlD 40O 19 Figure 8 Previously used solar trough used for producing electricity Image found at http thefraserdomain typepad com photos uncategorized 2007 07 28 solar trough 3 jpg 20
3. Reactor Material Shipping Fabrication Total Seller Schott North Glass Tube 210 46 0 0 210 America Schott North Insert Tube 110 0 0 110 America Coating 250 0 0 250 AET Solar threaded rod 25 08 0 0 25 1 Woodwrd Co 596 Reflector Material Shipping Fabrication Total Ribs 450 0 0 450 Threaded rod 25 08 0 0 25 1 Alanod 265 75 0 0 266 Anomet Solar Adhesive 50 0 0 50 Backing sheet 50 0 0 50 Wood 50 0 0 50 891 Square tube and Frame Aluminum Backer 153 35 0 0 153 Albany Steel Tracking circuit 90 0 0 90 Tracking drivetrain 210 0 0 210 Total Cost of the device 1786 37 91 Page Appendix F Decision Matrices Table 11 Reactor End Cap Matrix WOGIIIWUI Cat Wt ool Plain copper end cap Custom Steel end cap Custom Monel Kovar end cap a Weight Thermal Conductivity Ease of assembly Ease of glass replacement Total 100 0 08 0 16 0 12 92 Reactor End Cap o gt 3 Ki D Custom Monel K end Plain copper end cap Custom Steel end cap mu Figure 52 Reactor End Cap Results 93 Page Table 12 Glass Envelope Matrix Material Cost Schott DURAN Tubing Polymer Tubing Weight Optical Transmission 96 Reflectivity Dielectric Coating Robustness against physical shock Robustness against thermal shock Lifetime in UV Environment Ease of product
4. Price lt 800 51786 37 Payback period lt 10 years gt 10 years Amount of char created 2 Ib cycle 5375 Ib cycle Sustains a temp of 300 C Estimated to meet target value Amount of time required to touch a 0 sec Meets target value surface capable of causing burns Based on Table 1 User Needs 71 7 Conclusions In conclusion the tests that were performed showed that this project will most likely work in Ghana Since the tests were performed in New York at a higher latitude than in Ghana the sun was not as strong as it is in Ghana Thus when this device is used in Ghana the device should produce better results than the tests performed Also due to the latitude difference the angle that the device needed to be for testing here is different than the angle the device is designed for Because of this discrepancy the team believes the device will perform more effectively once it is in Ghana This discrepancy originated due to the alternate frame that was used during testing This introduced some frame twist and caused the reflector to slide out of position These issues will be resolved in Ghana because the alternate frame system will not be necessary in Ghana Finally the results showed that the required temperatures for torrefaction are possible in New York thus when this device is used in Ghana the required temperatures will be easily achievable 8 Future work Future recomm
5. 000000000000 en nennen nensi 44 Figure 27 A Frame Sketch Spring 2012 44 Figure 28 Reactor bracket Sketch Spring 2012 enne enitn enhn renta ressent nis 45 Figure 29 Current reflector frame design 46 Figure 30 Current frame design high del 47 Figure 31 Current frame design showing the low side and the support 47 Figure 32 Escapement mechanism Spring 2012 a 49 Figure 33 PSpice Circuit Schematic 50 Figure 34 Schematic for Torque calculations 51 Figure 35 Escapement mechanism Spring 2012 I 52 Figure 36 Assembled control box 0 m asuanata tapak kasus asawa nnns 54 377 Assembled control em 54 Figure 38 Circuit logic diagram for control system 55 Figure 39 Circuit power diagram for control box 56 Figure 40
6. PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING 1 THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION lt INSERT COMPANY NAME IS PROHIBITED NEXT ASSY USED APPLICATION 002 8 Clearance x2 016 X 45 00 x2 300 RPI Design Lob Biomoss DIMENSIONS ARE IN INCHES NAME PAIE TOLERANCES DRAWN FRACTIONAL ANGULAR MACH BEND CHECKED TWO PLACE DECIMAL 020 APPR THREE PLACE DECIMAL 005 EG aen MATERIAL Q A Alloy Steel COMMENTS FINISH Alexander Nolet xg DO NOT SCALE DRAWING SCALE 4 1 ShearDisc_Inner WEIGHT SHEET 1 OF 1 d 51 13 002 002 5 625 440 8 Clearance x2 020 X 45 00 x2 300 DATE DIMENSIONS ARE IN INCHES 2 TOLERANCES BU RPI Design Lab Biomass FRACTIONAL ANGULAR MACH BEND CHECKED TWO PLACE DECIMAL 020 ENG APPR Alexander Nolet THREE PLACE DECIMAL 005 PROPRIETARY AND CONFIDENTIAL MFG APPR THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY Alloy Steel COMMENTS lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF ED ON SUE DWG NO lt INSERT COMPANY NAME HERE gt IS A ShearDisc Outer PROHIBITED APPLICATION DO NOT SCALE DRAWING
7. Figure 29 Components such as the third support member of the frame and the additional reflector support bar were deemed unnecessary and were subsequently removed from the design In addition the new design already incorporates the angle necessary for the device to function properly in Ghana Figure 29 Current reflector frame design 46 Figure 31 Current frame design showing the low side and the support 47 Page 5 4 Control The tracking system is one of four components reflector reactor tracking system and frame In this section the concept selection analysis and design of the solar reflector will be reviewed The solar reflector is the portion of the unit that collects light from the sun and concentrates it on the reactor 5 4 1 Concept selection The initial concept for the tracking system was carried over from the previous design It utilized a differential voltage from two small solar cells as in the sensory input from the sun A large solar cell recharged a battery The battery was used to power a motor which turned the collector A simple analysis of a crosswind motivated the torque specification for the tracking system With this essential requirement an estimate of the cost of such a system was performed The cost for each component was bracketed with a minimum and maximum cost value determined through the research into possible vendors The final result was that such a system could comprise 1 3 of the
8. y sassa 5 6 Revision stop Sq 8 TEMS Abbreviati niSo 9 1 aideeye 10 J CSUOIWYIWAPV 12 1 2 User Needs and Problems 5 12 1 3 Justification for the 15 1 4 Project 15 1 5 Other Relevant Information 16 2 Project Objectives and Scope eerte ee it tta eae et eR Nen etx T a e NER da AE 17 3 Assessment of Relevant Technologies 18 3 1 18 3 2 Dehydrating Biomass e HERE E ER NE RR ERR ed 18 33 Charcoal StOVeSu uu s 19 3 4 Solar eu TEE 20 4 Professional and Societal Concerns 26 4 21 eei etl i u S 26 4 2 lee EE 26 26 4 4 uuu u M 26 5 Health and Safety su uyu uu a ie len v 27 5 System Concept Development 28 5 1 IE M 28 5 1 1 Conc
9. DATE DRAWN CHECKED ENG APPR MFG APPR Q A COMMENTS 10 1 Design Lob Biomoss SUE DWG NO A BushingFollowerRight SCALE 4 1 WEIGHT SHEET 1 OF 1 REV PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING 1 THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION lt INSERT COMPANY NAME IS PROHIBITED NEXT ASSY USED APPLICATION DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 020 THREE PLACE DECIMAL 005 MATERIAL Bronze FINISH DO NOT SCALE DRAWING 0 40 21 DRAWN CHECKED ENG APPR MFG APPR Q A COMMENTS 020 QTY 1 RPI Design Lab Biomass SUE DWG N A Bushin SCALE 8 1 WEIGHT gFollowerRightSpacer SHEET 1 OF 1 EV 14 00 60 00 7 9 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE gt IS PROHIBITED APPLICATION 5 4 55 USED DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL INTERPRET GEOMETRIC TOLERANCING PER MATERIA 3 4 Pl
10. While it is unlikely that the average Ghanaian farmer will be younger than 13 working on their own it is also unlikely that a farmer will be over 50 years old working on their own this also dictates part weight Parts require 2 parts significant energy to fit together Amount of force lt required by difficult to fit parts Estimated by personal experience Will assemble and disassemble the torrefaction unit out of the crate then use it 76 Page Lightweight Weight of heaviest part 40 Ib http www hsbaseballweb com weig ht lifting htm Seems that most pubesant males can lift 10 15lb 1 arm in repetition so 2 arms between 2 people so 40 Ib seems reasonable parts will be weighed Easy to Use A Ghanaian farmer can use the system Limit actions to use Steps for setup 3 step s will need to unweight crank and weight the system Steps for batch 5 step s will need to pack unload load lift and slide the system Should use the system and count Limit length of Time to set up for day 10 min time of work per day should not actions greatly exceed 1 hour Time for batch process 15 min Limit strength Max pounds required 20 Ib As in source X 13 year olds start at 15 required Ib repetitive lifting Works in Ghana Elemental Resistance Design electro Nema Rating for Nema 5 keeps out dust and water in windy purchasing only
11. 280 0 200 DATE DRAWN CHECKED ENG APPR MFG APPR Q A COMMENTS 10 QTY 1 Design Lab Biomass SUE DWG NO A BushingFollowerLeft SCALE 4 1 WEIGHT SHEET 1 OF 1 REV PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING 1 THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE 5 PROHIBITED NEXT ASSY USED ON APPLICATION DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE PLACE DECIMAL 005 MATERIAL FINISH DO NOT SCALE DRAWING 0 40 5 21 NAME DATE DRAWN CHECKED ENG APPR MFG APPR Q A COMMENTS QTY 1 RPI Design Lab Biomass SUE DWG N A BushingFollowerLeftSpacer SHEET 1 OF 1 SCALE 8 1 WEIGHT REV PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING 1 THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION lt INSERT COMPANY NAME IS PROHIBITED NEXT ASSY USED APPLICATION 0 40 5 144 DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE PLACE DECIMAL 005 MATERIAL Bronze FINISH DO NOT SCALE DRAWING 150 TO 200
12. N 1 Q 1 UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL x TWO PLACE DECIMAL THREE PLACE DECIMAL 005 INTERPRET GEOMETRIC TOLERANCING PER MATERIAL Aluminum 6061 FINISH DO SCALE DRAWING 63 DRAWN CHECKED ENG APPR MFG APPR Q A COMMENTS NAME DATE 52 0 300 0 250 TITLE Quantity 2 Shaft Seal Mount SIZE DWG NO A SCALE 2 1 NEXT ASSY USED ON MATERIAL FINISH WEIGHT 1 OF 1 4 1 ITEM NO PART NUMBER Description ExpViewConfig QTY 1 ShearDisc Outer Fabricated 1 2 SheorDisc_Inner Fabricated 1 3 ShearDisc_SprinPin OTS Mcmaster 1 UNLESS OTHERWISE SPECIFIED NAME DATE 5 Design Lob Biomoss DIMENSIONS ARE IN INCHES DRAWN TOLERANCES FRACTIONAL TITLE ANGULAR MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS COMMENTS MATERIAL DRAWING IS THE SOLE PROPERTY OF SIZE DWG NO lt INSERT COMPANY HERE S hearDisc ASSy REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON lt INSERT COMPANY NAME HERE gt IS PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 1 1 WEIGHT SHEET 1 OF 1 5 4 3 2 1 002
13. something does break it is look up potential suppliers components replaceable in Ghana likely it can be fixed of components in Ghana no direct test Low cost Ghanaian farmers can Reduce number of Price lt 800 In order to have a payback period lt 10 Purchase orders BOM receive a loan or grant for enough to buy system components amp use inexpensive components years Payback Period lt 10 years Decided based on lowest achievable cost calculations based on value output and cost no direct test 78 Page Creates Biochar Creates biochar for cooking fertilizer Design reactor to hold biowaste amount of char created kg 741 1 5 ke Based on previous tests amp calculation this should provide fuel for a 4 person family on 1 acre use system Design reactor Sustains a 300 C Maximum efficiency for the Apply thermocouples thermally efficient temperature of torrefaction process during use Safe The system does no Limit ability to look Amount of solar 1 sun They merely have to walk 2 feet away design to spec direct harm to farmers or into reactor intensity that test their neighbors and bystanders are families exposed to Amount of times you 0 times So that one does not need to risk have to look at the retinal damage to use the system reflector to use device Does not require Amount of time 0 minutes Don t want to burn anyone contact
14. 5 w cos 2 inc LineWidth rw end end axis 5 w 2 r 5 w 2 r c r aor 2 r axis equal PLOT RAY OFFSET D 3 W 100 sam 2 5 FLR 25 30 35 A0 45 pw 3 113 R 0 2 w W R zmin 0 zmax 1 5 length FLR for n 1 N x z RayOffset D W FLR n sam if n end Remove the garbage data near 0 most likely a result of roundoff and cosine of small angles floor length X 2 floor length X 50 for i 1 length FLR Z i j k j k linspace Z i j k Z i j k 2 k 1 end clf 114 Page figure 2 hold on plot transpose X transpose Z LineWidth pw legend num2str transpose FLR Location SouthEast plot 5 w 2 5 w 2 1 1 LineStyle Color 0 0 0 LineWidth pw line 5 w 2 5 w 2 1 1 LineStyle Color 0 0 O LineWidth pw line w 5 2 w 5 2 zmin zmax LineStyle Color 1 0 0 LineWidth pw line w 5 2 w 5 2 zmin zmax LineStyle Color 1 0 0 LineWidth pw line w 75 2 w 75 2 zmin zmax LineStyle Color O 1 0 LineWidth pw line w 75 2 w 75 2 zmin zmax LineStyle Color O 1 O LineWidth pw axis 5 w 5 w zmin zmax xlabel Collector Width All distance normalized to reactor radius ylabel Reflected Light Ray Offset from Reactor Centerline text w 5 241 1 25 5094 text w 75 241 1 25 7594 text 0 05 R
15. Figure 9 Reflector Surface 28 Figure 10 Matlab Analysis showing effects of misalignment 29 Figure 11 Analysis for parabola optimization generated by a Matlab Script shown in Appendix H 31 Figure 12 Reflector preliminary design 31 Figure 13 Current reflector designs es oreet er ene Ve ES VAR 32 Figure 14 Reactor Receiver Assembly n tres ee tenen nnne 36 Figure 15 Decision Matrix insert removal methods essere 36 Figure 16 Henry Wettersen shown using the hooks to remove the reactor insert 37 Figure 17 Reactor Receiver with Insert 37 Figure 18 Thermal FEA Results sectioned view 38 Figure 19 Thermal FEA Results full assembly n a 38 Figure 20 Thermal FEA Results insert only 39 Figure 21 Reactor end view 40 Fig re 22 Reactor both ends et tt e ett E Q ST EN 40 Figure 23 Reactor Receiver Assembly with Insert essere n ennt 41 Figure 24 Reactor Mounting Bracket 41 Figure 25 Actual reactor showing the mounting bracket 42 Figure 26 Reflector Sketch Spring 2012
16. T 4 Outer Glass Surface Inner Glass Surface T 3 Outer Reactor surface T 2 Inner Reactor surface T 1 Outer Reactor Insert surface 105 Page T 0 Inner Reactor Insert surface Other q_Sol 10000 Solar Irradiation W m 2 L 0 90 m q_Solar q_Sol L Solar Irradiation normalized for length of reactor W m Solar Absorption W m 5 SolAbs q Solar 0 08 Absorption in Glass 3 SolAbsz0 95 q Solar epsilon Absorption outer Reactor surface Convection W m q_12_conv h_1_Air pi D 2 T 2 T 1 Inner Reactor wall to Inner Air 34 conv h 1 Air pi D A T 4 T 3 Inner Glass to Annulus 56 conv h 56 Air pi D 5 T 5 T 6 Outer Glass to ambient Conduction W m q_01_cond 2 pi k_Reactor T 0 T 1 In D 1 D 0 Through Reactor insert wall 23 cond 2 pi k Reactor T 2 T 3 In D 3 D 2 Through Reactor wall 45 cond 2 pi k Glass T 4 T 5 In D 5J D 4 Through Glass wall Radiation W m 34 rad sigma pi D S T 3 4 T 4 2 1 epsilon 1 epsilon_4 D 3 epsilon_4 D 4 Outer Reactor surface to inner Glass surface 57 rad sigma pi D 5 epsilon 5 T b 4 T 7 4 Outer Glass surface to sky 106 Page Energy Balances at each surface of the Solar Receiver cross section to Outer Negecting heat losses through frame bracket 0 Convection inner reactor surface to inner air conduction through Reactor Insert wall 1
17. the overall goal was to make the device as cheap and long lasting as possible while providing the highest yield to ensure the greatest value and quickest payback to the customer It was also important that the device be safe and while not essential strongly preferred that it be simple to use as ease of use increases the probability that it will be used consistently Ultimately ensuring the Ghanaian farmers adopt this device is the final challenge of this project 12 Page Table 1 User Needs Customer Requirement Technical Requirement Approach Technical Specification Target Value Easy to assemble A Ghanaian farmer can All parts needed Number of instruments parts 0 assemble the system included needed not in crate Parts fit together Number of persons required 1 easily Age of persons required 15 50 Light weight of heaviest part 4016 farmer use the Limit actions to use Daily setup steps 3 system Number of steps for batch 3 Limit length of Time to set up for day 15 min actions time for batch process 15 min limit strength Lifting weight 2016 required Works Ghana Weather resistant weather resistant components are tolerant of 20 mph wind speeds found in Ghana Components are tolerant of 1000 ppm particles Number of circuits that fail in 0 rain Design for operation in Ghana Accurately designed Uses correct elevation an
18. 1 end ArcLength ArcLength sqrt yp n yp n 1 2 xp n xp n 1 2 end TrueArcLength ArcLength R theta 1 theta 2 theta Num theta Num 1 plot TS 1 theta Generate Offset Parabola for n 1 Num if xp n lt 0 TSO n TS n sin theta n cos theta n ope else TSO n TS n sin theta n cos theta n ope 111 end end 2 7 5 1 RRay zeros 2 Num N zeros 2 Num for n 1 Num inc theta n ape RRay n fp 1 TSO 1 n fp 2 TSO 2 n if xp n lt 0 N n sin inc cos inc del acos dot RRay n N n mag RRay n mag N n inc else N n sin inc cos inc del acos dot RRay n N n mag RRay n mag N n inc end z n sqrt RRay 1 n 2 RRay 2 n 2 sin del if xp n gt 2 amp amp xp n lt 2 disp del end end Plot Reflector with reference rays figure 1 clf hold on 112 plot TSO 1 T50 2 g LineWidth pw circle fp 1 fp 2 r k for 1 Num Div Num Num inc theta n ape line TSO 1 n fp 1 TSO 2 n fp 2 Color 0 1 01 line TSO 1 n TSO 1 n TSO 2 n 1 2 fl line TSO 1 n TSO 1 n N 1 n TSO 2 n TSO 2 n N 2 n Color 1 0 0 if xp n lt 0 line TSO 1 n TSO 1 n 4 5 w sin 2 inc TSO 2 n TSO 2 n 5 w cos 2 inc LineWidth rw else line TSO 1 n TSO 1 n 5 w sin 2 inc TSO 2 n TSO 2 n
19. 9 in Lb With Aluminum on Aluminum contact and 2 5 in diameter escape wheel the friction on the follower holding the escape wheel is Tin 5 Fescape friction Hs 8 6 in lb zd 5 The force the cam varies over the course of its rotation It is maximum when the offset direction from center is perpendicular to the contact point to the center Assuming a 1 5 Ib spring and cam has a mechanical advantage of 2 with respect to the spring the force on the cam is Tout Tspring 6 F iction Foring 9 3 lb 6 escape friction spring m lb The friction force is perpendicular to the cam force Now inserting the respective radii a solution for the minimum cam torque is found 7 Tcam max Tcam of f set T u Tcam radius 5 6 im z ib This will be used in the selection of the gear motor that will actuate the cam 121 Appendix K CAD Section CAD Images Tracking System Follows Sun Reflector Concentrates sunlight Figure 61 Complete CAD Model of the device Figure 62 Reactor Receiver with Insert 122 Page Figure 63 Reactor end view Figure 64 Reactor both ends 123 Page 124 Page 8 7 5 4 3 2 1 ME PART NUMBER Description OTS 1 2 GearboxCov
20. MJ 2 41 MJ 3 From the average Ghanaian solar intensity 1 m collector the total time required to torrefy 1 kg is 2 _ 5 11 H 4 0 75 The design outlined in the reactor section of this paper holds an estimated 1 25 kg of biowaste and has an average normal area of 2 m Assuming that 5 of solar radiation is lost per glass air transition as suggested by Professor Borton the total cook time per reactor load is then 125 kg 750 77 T 66 m x 1 kg 1500 0 9573 48 m 5 120 Page Appendix J Torque Calculations 1 F gt 1 Where d is approximately one third of the arc length of the panel 3 At a wind speed of 20 mph and panel at 45 degrees as shown the approximate torque on the panel is 125 in Ib This calculation was used to determine the rated driving torque for the collector A gearbox with a rated output torque of 445 in Ib was selected There is a concern that a passerby will hang from the edge of the collector A 250 Ib person could exert 10 000 in Ib on the gearbox If this is deemed an unacceptable failure mode that requires mitigation then there are two clear paths First the gearbox could be oversized to accommodate this load or a clutch or torque limiting device is placed in the drive train 7 60 Therefore for the rated output torque of 445 in Ib the input torque is 4 Tin eret
21. SCALE 2 1 WEIGHT SHEET 1 OF 1 8X 125 THRU ALL 450 v 200 4X 201 THRU ALL L 375 y 200 Bottom 4 850 2X 6 Clearance THRU FACE 2X 150 THRU UNLESS OTHERWISE SPECIFIED MAME Il DIMENSIONS ARE IN INCHES DRAWN RPI Design Lab Biomass TOLERANCES FRACTIONAL TITLE ANGULAR MACH BEND TWO PLACE DECIMAL s 02 ENG APPR THREE PLACE DECIMAL 005 MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS e PER STE MATERIAL DRAWING IS THE SOLE PROPERTY OF SIZE DWG REV lt INSERT COMPANY NAME HERE gt ANY MATERIAL Ps SolarPanelandPulleyMount REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF FINISH USED ON INSERT COMPANY NAME HERE IS APPLICATION DO NOT SCALE DRAWING SCALE 1 4 WEIGHT SHEET 1 OF 1 PROHIBITED OF 1 5 4 3 2 1 0 40 0 144 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE IS PROHIBITED NEXT ASSY USED ON APPLICATION DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE PLACE DECIMAL 005 MATERIAL Bronze FINISH DO NOT SCALE DRAWING
22. Spring 2012 finished the project by creating a reproducible prototype and for shipment to Ghana The design has been divided into four major subsystems Reflector Reactor Tracking System Control and the Frame These four subsystems work in conjunction to convert the agricultural waste into char for cooking or fertilizer use The char can be pressed into briquettes for stove applications as needed Alternatively the farmer has the option of selling his briquettes for profit for a source of income After the payback period the farmer will start to make a profit from selling these briquettes 10 Tracking System Follows Sun Reactor Absorbs sunlight Reflector Concentrates sunlight 11 Page 1 1 Report Summary This report begins with a discussion of the needs of Ghanaian farmers and a brief project history Then the report covers the project objectives expressed at the beginning of the semester and the final outcomes relation to those objectives Then any existing technology that is similar to this new device This is followed by any political and societal concerns that may arise from the introduction of this product to Ghana Next the design process system evaluation and specifications will be covered to describe this device These sections will include a more detailed account of the history of development of each subsystem the final design of each subsystem the intended use of this device and any testi
23. can be broken down for transport Frame meets requirements Perform energy analysis to determine an accurate cycle time for the reactor Tested cycle time is consistent with analysis results within 15 min Decide on a technique to automate solar tracking Technique was determined and apparatus was designed and constructed Explore shipping challenges to Ghana including both cost and export controls Proper crate was acquired meeting international shipping requirements Shipping is being sponsored by Boeing Create a user manual to accompany the finished prototype to Ghana Finished user manual included in the crate to be shipped to Ghana Perform real world testing Collect corn cob input size information about Conducted tests using different corn cobs sizes for throughput Identify and rectify problem areas in design Developed and constructed a bracket to hold the reactor insert in place adjustments made to the reflector to ensure it rotated without issue Deliver working prototype to contact in Ghana Finished prototype is ready for shipment to Ghana 17 Page 3 Assessment of Relevant Technologies 3 1 Torrefaction Torrefaction is a process which involves heating cellulose commonly wood to temperatures around 300 C to produce charcoal While many other approaches to create charcoal from wood by burning another fuel source to heat the wood into charcoal this design
24. for a few hundred nanoseconds The trigger also turns R S flip flop 2 FF2 ON and resets flip FFO 010 FF2 is controls the state of the motor FFO stores the state of the 7 bit counter Once 7 bit counter UA is reset it begins to count anew Each of the seven outputs of U4 is connected to dip switch SW4 This is a selector it passes through a specific count to the SET of FFO This is used to ensure that the motor is not prematurely turned off when it is turned on and the limit switch is still depressed The output of FF2 connects to the gate of MOSFET 01 which controls the operation of the motor See the section on the power aspect of the electronics for a description of that portion of the circuit The motor starts to turn counter clockwise releasing the limit switch Then the count is reached in U4 and FFO is set The cam connected to the motor moves the followers allowing the catch wheel to rotate 60 degrees The cam completes its revolution and depresses the limit switch The motor enable output of FF2 the limit switch and output of FFO are AND ed together by 3 input AND gate U11 The output of this resets the motor enable FF2 Two 6 Volt photovoltaic panels PV1 and PV2 provide to the power to the electronics Each of the panels has a Shottkey diode across it D1 and D2 respectively These are used for balancing of the solar cells and safe discharging of the capacitor bank PV1 and PV2 are connected in series to provide the 1
25. friend connecttheaxelsto thetwostruts Put one washer oneither side and connecta nut Attach the Cross Bar Puta bolt through the bottom cross bar and connect a nut One bracket onto the top cross bar 21 Page Screw the Bracket to the Reactor Lift the reactor into line with the bracket Adda screw in each of the holes Slip the other bracket in without letting go of the reactor and screw it in Line up the four mounting studs and drive shaft Slide power assembly onto frame Use XX T Handle to tighten the two screws in the shaft coupler 22 Page Connect Locknuts Putthe 45 16 Locknuts onto the mounting studs Tighten with 1 2 Inch Wrench Locknuts Daily Setup Daily Setup Completely Unwind the Rope fromthe drum ThreadtheRopethroughthe Pulley onthe box ThreadtheRopethroughthe Pulley onthe Weight Pail TietheRopeto theLeftEyeon the Box so that the Weight Pail is just offthe ground Byhand loopthe rope around the drum until the reaches thetop ofthe travel FillthePail with sand orrocks 23 Page Every Cycle Setup Load The Insert Putthe dried corn cobs in It s easiest and most effective if they are cut up Insert the Insert Slip the insertup into the reactor 24 Page Remove Insert Use the two hay hooks to removethe insert Unload Insert Tip the insert using the
26. gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY IS PROHIBITED APPLICATION NEXT ASSY USED ON 5 4 UNLESS OTHERWISE SPECIFIED DI MENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH TWO PLACE DECIMAL THREE PLACE DECIMAL TERPRET GEOMETRIC TOLERANCING PER FI Mild Steel ISH Mill DO NOT SCALE DRAWING 3 BEND NAME DATE Design Lab Biomass DRAWN CHECKED TITLE ENG MEG APPR Lower Flange WJ Q A COMMENTS uantitv 1 SIZE DWG NO REV Q y A Lower Flange WJ 2 SCALE 1 2 WEIGHT SHEET 1 OF 1 2 1 3 500 88 90mm 6X DRILL 25 v 0 45 TAP 10 24 v 0 25 MIN 0 500 12 70mm d 5 D 0 375in 9 53mm 0 250 6 35mm i 1 4 S a le E S S EQ S S 6 Eo Zoa e N E E B SCALE 1 1 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN HBW 2 29 2012 Design Lab D Biomass FRACTIONAL CHECKED TITLE TWOPLACEDECIMAL 001 L E PE 5 THREE PLACE DECIMAL 0 005 APPR to na TOLERANCING COMMENTS MATERIAL MILD STEEL f SIZE IB ps E d REV FINISH AS MACONED Quantit
27. in square box tube 11 875 in long with 3 8 16 threaded rod running through the tube segments and across all five ribs Nuts are threaded on the rod where it protrudes from the outermost rods allowing the entire structure to be drawn together by tension on the threaded rod Five of these rod tube assemblies are used on the reflector 33 Page 5 2 Reactor The reactor is one of four components reflector reactor tracking system and frame In this section the concept selection analysis and design of the reactor will be reviewed The reactor is the portion of the unit that absorbs sunlight and transmits the energy in the form of heat to the biomass thus charring it 5 2 1 Concept selection The Reactor is the portion of the solar torrefaction unit that stores the biomass absorbs the concentrated light and heats the biomass 5 2 2 Background An effective biomass converter absorbs most incident solar radiation and emits little energy in the form of reflected or re radiated light The reactor is at the center of the device the primary goal is to produce char from biomass An efficient reactor continuously maintains good chemical conversion throughout its daily and yearly use Previous semesters developed a variety of concepts for the reactor See Table 4 Most of these methods suggested i e Silvering the inside of the glass envelope had not undergone full analysis and upon further review were determined to be infeasible with
28. outside tube and corncob versus time respectively This test data shows the corncob temperature starting to equalize with the outside tube temperature at about 25 minutes The two plot lines increase to 307 Celsius at 35 minutes and then remain at this temperature without much variance After an hour of operation the insert does reach the necessary torrefaction temperatures and hold at steady state This shows the system does have the capability to torrefy the biomass and should have an increased effect in Ghana 6 2 3 Control Power Testing Two tests were performed to verify the systems performance in power adverse conditions One test examined the ability of the system to store power The other test examined the discharge rate using the motor At the conclusion of the testing a determination in either the affirmative or the negative can be made as to whether a situation can arise when the system cannot actuate itself Each of the photovoltaic panels is rated for 2 Watts at 6 Volts The test assumes that the panels are not operating at peak performance and instead are running at 7 of rated power Running at half power the panels are expected to supply 83mA to the circuit The capacitors are assumed to be fully discharged Using Bench top Supply 12 Volts with a limit of 8 was set The capacitor charged to 9596 of 12 Volts in 2 minutes 44 seconds Note that this is less than the 4 minute wait time between motor actuations 68 Pa
29. period the limit switch goes from CLOSED to OPEN After yet more time the short clock pulse ends and clock goes back to HIGH The motor completes its revolution and trips the limit switch setting it to CLOSED The NANDed combination of the clock HIGH limit switch HIGH and motor ON enables the trigger of the 555 on the left This 555 is configured as a one shot The output pulse resets the S R flip flop thereby turning the motor off The system then waits for another LOW pulse from the clock Rotation Axis Figure 34 Schematic for Torque calculations 51 Page 5 4 3 Preliminary Design As shown by previous groups researchers the torrefaction unit cannot function without solar tracking While previous groups used a motor it was determined after much discussion which a longer lasting and cheap solution would be to use a small electrical escapement and weight system This weight driven system as seen Figure 35 consists of an escape wheel release mechanism and a cam control Escape wheel Release mechanism Cam control Figure 35 Escapement mechanism Spring 2012 5 4 4 Final Design The desired operation of the system is to drive the solar panelat an average speed of precisely 15 degrees per hour The panel 15 driven by falling weight the controller allows the input to rotate 60 degrees This is accomplished by actuating the panel 1 degree every 4 minutes Crystal oscillator Y1 generates a 4 MHz clock
30. section The impact of these requirements on the design of the system will be illustrated here Perhaps the most important component of the design is that the torrefaction unit must produce biochar In particular it should produce 2 Ib hr in order to meet NCIIA s specifications In order to achieve this a thermal analysis was performed on the reactor as described in 5 2 3 Analysis Further analysis was performed to ensure that sufficient power is provided to the reactor at any given time It is also important that the design not be prohibitively expensive and that its payback period not be excessive Based on payback calculations for every 100 dollars of the project cost the payback period can range between 8 2 5 years While this will be difficult to achieve it can be best achieved by keeping lowest cost solutions in mind using the cheapest material that will work and reducing manufacturing costs by using off the shelf components wherever possible Weather resistance is an important component for functioning in Ghana In particular the design must be tolerant of dust wind and water This can be achieved by reducing the number of openings in the electro mechanical systems and ensuring all openings are sealed or not exposed Any components that are exposed must be tolerant of exposure 14 Page The system should be straight forward to assemble requiring no more force than a 15 50 year old can apply ought not
31. the goal of creating throughput 5 1 Reflector The solar reflector is the portion of the unit that collects light from the sun and concentrates it on the reactor 5 1 1 Concept Selection The reflector s purpose is to direct solar energy to the biomass being processed to heat it to a temperature range at which torrefaction is accomplished 220 C 280 C Edward S Lipinsky 2002 The simplest method to accomplish this heating would be to lay the biomass on a flat plane and allow the sun to heat it until it underwent the chemical conversion Unfortunately sunshine is not of sufficient intensity on Earth to accomplish flat plane torrefaction as natural convection keeps the temperature too low In order to reach the desired temperatures some form of concentration is necessary Previous groups examined different collection technologies and settled upon a trough design For the purposes of this discussion a standard 1 m reflector will be used This means that the projected reflector area normal to the light source Sun is 1 m T Figure 9 Reflector Surface In Ghana the solar intensity can vary between 550 w m and 1075 w m Asiedu Bondzie 1986 and the analysis presented here will assume an average of 750 W m in all calculations 28 Page 5 1 2 Analysis Assuming a reactor load of 1 25 kg dehydrated biomass and a reflector area normal to the sun of 2 and an average solar intensity of 750 w m
32. these two readings could help analyze the ambient temperatures effect on the system performance From the testing result the test B outside temperature is 22 Celsius higher than test 1 As the test B was conducted at a higher temperature it indicates that the ambient temperature actually affect the temperature of the reaction tube can get up to Both tests show upward trends for both inside and outside temperatures during the 1 hour test This indicates that the temperature would have continued increasing if the tests were continued 300 250 200 150 100 Temperature 50 0 200 400 600 800 1000 1200 1400 1600 1800 50 Time Second Figure 48 Test C Temperature 5 07 2012 11 40 66 Page 300 250 200 150 100 Temperature C Np 50 0 200 400 600 800 1000 1200 1400 1600 1800 50 Time Second Figure 49 Test D Temperature 5 07 2012 14 53 In order to test the effectiveness of the glass on the system performance tests C and D were conducted on the second day The inside temperature readings were taken from the inside of a corn cob which is a more accurate way to test the product The inside of the corn cob reached up to 226 Celsius at 26 minutes and the reactor tube reached 231 Celsius at only 7 minutes Due to the thermocouple and LabVIEW range issue the thermocouples stopped reading at around 230 Celsius This happe
33. to replicate the current prototype after testing in Ghana 4 5 Health and Safety Prolonged viewing of the reflector near the focal length can be hazardous causing retinal damage Moreover the device may reach around 280 C which can burn human skin very quickly As such safety precautions were taken Looking into the reactor while focusing the system for the day occurs at an angle and distance that keeps the user s eyes safe Moreover hay hooks with special coatings are used whenever touching hot components Also the team advises the user to use sunglasses or welding goggles and gloves while using the device Both looking into the reflector near the focus and touching hot surfaces is immediately painful and it is hoped that no one will repeatedly make that mistake However It is still possible for someone to injure themselves using this system In particular the group found that setting up the system and resetting it particularly for those not doing the resetting are at risk for Flashing It is also possible for people to mistake cool insert for a hot if not careful 27 Page 5 System Concept Development The entire system consists of a reflector reactor control tracking and a frame This system takes pre dehydrated corn cobs and converts them into biochar It does this through a process called torrefaction The sections below will talk about the Spring 2012 semester s designs in each of these areas to achieve
34. will not function from October to February during Sarmahatten but it will function on most other days when it is merely cloudy Safety has been considered throughout the design process Dangers of solar collectors include burning oneself and retinal damage from concentrated sunlight In particular use of hay hooks to insert and remove hot inserts and physically positioning components to make it hard to flash one s self while operating the system were designed in These are discussed in more detail in section 4 5 and the process of use is discussed in more detail in section 5 6 16 Page 2 Project Objectives and Scope Table 3 Semester Objectives with the matching final outcomes Semester Objective Final Outcomes Refine Thermal analysis of the reactor and check assumptions of past work Performing hand calculations and FEA after performing radiative heat transfer analysis Use results of thermal analysis both manual and computer models to drive design decisions with regard to reactor materials and geometry System designed using the analysis performed Examine and mitigate safety hazards associated with operation of the collector Safety considerations accounted for in final design Develop prepossessing loading and unloading procedures for maximum throughput Device used and user manual created and included in the appendices Design a frame for the collector that is lightweight easy to repair and
35. 0 005 1 57 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE gt IS PROHIBITED 10 Clearance Hole x4 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN TOLERANCES FRACTIONAL CHECKED ANGULAR MACH 3 BEND TWO PLACE DECIMAL 010 ENC APP THREE PLACE DECIMAL 005 MFG APPR INTERPRET GEOMETRIC Q A TOLERANCING PER COMMENTS MATERIAL Alloy Steel Alexander Nolet FINISH NEXT ASSY USED ON APPLICATION DO NOT SCALE DRAWING 4 3 2 020 X 45 00 Lab Biomass TITLE SIZE DWG REV GearboxCover SCALE 1 1 WEIGHT SHEET 1 OF 1 Pim E g Matches Hole in Box Modification Fits on Locating Step on Gearbox 005 Suggestion 52 680 090 1 Bolt Plate into Enclosure 2 Drill 5 8 Clearance Hole through back of box and gearbox mounting plate 3 Use hole in plate as reference 3X D 299 Y 080 3X 7mm Clearance 6X 4 Clearance 4X 177 THRU ALL 8 Clearance 4X Existing Mounting Holes 2 750 235 Modify Existing Plate UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN Design Lab Biomass TOLERANCES TITLE FRACTIONAL CHECKED i ANGULAR MACH BEND TWO PLACE DECIMAL s 0
36. 1 8 WEIGHT SHEET 1 OF 1 3 2 1 D 625 THRU Se d 52 0 DETAIL B DETAIL C SCALE 1 2 SCALE 1 2 UNLESS OTHERWISE SPECIFIED NAME DATE p L b B DIMENSIONS ARE IN INCHES DRAWN HBW 3 21 2012 77 10mass TOLERANCES TITLE ANGULAR 0 5 CHECKED TWO PLACE DECIMAL 0 050 ENG APPR THREE PLACE DECIMAL 0 005 MEG APPR Low Side TOLERANCING PER 17x 0 072 Sq Steel Tube SEE DA NO REV Low Side DO NOT SCALE DRAWING SCALE 1 8 WEIGHT SHEET 1 OF 1 7 6 5 4 3 2 1 3 500in 88 90mm DRILL 9 THRU 0 137 3 l8mm 3 00 76 20mm 5 00 127mm Y SECTION A A UNLESS OTHERWISE SPECIFIED NAME DATE H DIMENSIONS ARE IN INCHES DRAWN HBW 12 29 2012 Desig n La b 1071955 TOLERANCES FRACTIONAL TITLE NGULAR MACH 0 5 BER BECA 0 010 ENG APPR THREE PLACE DECIMAL gt 0 005 MFG APPR Lower F n INTERPRET GEOMETRIC Q A TOLERANCING PER COMMENTS MATERIAL Flange 7 AS MACHINED Quantity 1 B g 2 DO NOT SCALE DRAWING SCALE 1 1 WEIGHT SHEET 1 OF 1 2 1 3 Note This schematic is for use as a water jet cutting reference only Do not use to machine other features 05 00 23 00 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING 1 THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE
37. 2 Volts needed to run the motor MG1 Connected in series to 12 Volts and Ground 5 capacitors C1 C5 and 5 Zener diodes D3 D7 The zen er diodes are each connected across a capacitor The Zener diode provides over voltage protection for the capacitors The capacitors are setup in series because electrolytic capacitors have a small maximum allowable voltage The equivalent capacitance of the bank is 1F Toggle Switch SW1 mounted to the side of the box controls power to the motor as well as to DC DC converter U1 U1 converts a voltage up to 38 Volts to regulated 5 Volts No external capacitors are needed for smoothing A shottkey diode of the same type as mentioned previously is connected across the motor to protect the circuit from back EMF 53 Page Solar Panels ___ Escapement Mechanism Figure 36 Assembled control box Solar Panels Output Shaft Escapement Mechanism Figure 37 Assembled control box 54 Page R12 2 2k llipi HHH Y 4 MHz Oscillator Figure 38 Circuit logic diagram for control system 55 Page A8187 SOT MOTOR DG Figure 39 Circuit power diagram for control box 56 Page 5 5 Process of Use The process of use section roughly details how one uses the solar torrefaction system Many of these details are included in the User Manual Appendix F The method of operating the device breaks roughly into three categories initial setup daily setup and cycle setup The initial
38. 2 conv q 01 cond 1 Convection inner reactor surface to inner air 2 conduction outer reactor surface to inner reactor surface 12 23 cond 2 Solar Absorption on outer reactor surface convection on outer reactor surface radiation from outer reactor surface to inner glass surface conduction though reactor wall 3 SolAbs q 34 conv q 34 rad q 23 cond 3 Convection convection on outer reactor surface radiation from outer reactor surface to inner glass surface conduction through glass wall 34 conv q 34 45 cond 4 conduction through glass wall Solar Absorption on outer glass surface convection outer glass surface to ambient air radiation outer glass surface to ambient 45 cond q 5 SolAbs q 56 conv q 57 rad 5 Heat Loss convection outer glass surface to ambient air radiation outer glass surface to ambient HeatLoss q 56 conv q 57 rad 107 Page Appendix H Reflector analysis Incident Light on Reactor for Various Focal Length Ratios at 2 Degrees Angular Error 1 5 Reactor Surface 0 5 Reflected Light Ray Offset from Reactor Centerline Reactor Centerline 1 1 1 1 1 30 20 10 0 10 20 Collector Width distance normalized to reactor radius Figure 60 Reflector focal length analysis Tolerance to Angular Misalignment Reactor Surface Angular Misalignment Reflec
39. 500 Purely Conceptual not implemented or tested Not possible for this length of glass tube Cons Threading is costly Can t be operated by one person Cons Expensive Not manufacturable in Ghana Materials not available in Ghana 35 Page Glass Envelope id cap with flange Figure 14 Reactor Receiver Assembly The reactor design is focused on creating the most thermally efficient device possible in order to achieve a maximum throughput and quality of product biochar This requires a solar selective coating on the absorber and glass enclosure to prevent large convection losses The design is focused on being very user friendly Determining the proper loading unloading mechanism was not trivial To assist in the decision a decision matrix was constructed Figure 15 The double hay hook was determined to be the most fitting application Predicted costs Direct risk Indirect risk Ease of use Intuitiveness Consistency Ease of production o Nn 5 4 0 0 1 1 4 5 0 0 1 1 0 0 0 0 0 0 0 22 0 27 0 23 a Figure 15 Decision Matrix insert removal methods 36 Page Figure 16 Henry Wettersen shown using the hay hooks to remove the reactor insert The figure below shows the overall assembly of the reactor receiver including the insert Glass envelope Figure 17 Reactor Receiver with Insert 5 2 3 Analysis Figure 16 18 sho
40. ERANCES TITLE FRACTIONAL CHECKED 30 4 APPR NEMA Enclosure Mods A THREE PLACE DECIMAL 005 MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL TOLERANCING PER COMMENTS sel AR SE EES SIZE DWG NO EN INSERT COMPANY NAME HERE ANY 4100806 Modified REPRODUCTION IN PART OR AS A WHOLE FINISH B WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON lt INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 1 2 5WEIGHT SHEET OF 1 8 7 5 4 3 2 1 0 100 0 005 00 236 0 000 IHRU 00 50 0 13 1 00 0 50 0 350 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE gt IS PROHIBITED NEXT ASSY UNLESS OTHERWISE SPECIFIED DIMENS 8 32 Tapped y 0 6 ONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE P INTERPRE TOLERA LACE DECIMAL 2 005 T GEOMETRIC PER MATERIAL FINISH USED ON CRS APPLICATION DO NOT SCALE DRAWING 4 3 NAME DATE DRAWN CHECKED ENG APPR MFG APPR Q A COMMENTS Alexander Nolet QTY 1 RPI Design Lab Biomass TITLE SIZE DWG NO A SCALE 2 1 Com WEIGHT REV 5 1 1 Real
41. Figure 33 PSpice Circuit Schematic 5 4 2 Analysis The solar day varies from the mean solar day by 0 035 over the course of a year If the maximum useable angle of the sun is 45 degrees from high noon then this will at most result in error of 05 degrees at the end of the day The tolerance for the tracking timing was determined similarly If a misalignment of 6 degrees is tolerable at the end of the day 6 hours of run time then the speed can vary as much as 1 degrees hour or 67 This assumes that the user never verifies the tracking accuracy during the day but sets it accurately in the morning The timing circuitry will be constructed to be adjustable within these limits Testing will be performed to ensure that the temperature influenced variation in the timing does not exceed these values 50 Page The control circuitry was iterated upon several times The goal was to reduce the number of components needed The final design shown below uses a dual 555 timer a 7400 dual NAND 7410 triple NAND a power transistor system switch limit switch solar cell and a selection of resistors and capacitors The controller works as follows An S R flip flop holds the current state of the motor The output of this controls the power transistor which runs the motor A brief low pulse approximately the period of the gear motor output from the unstable oscillator the right 555 sets the motor to ON The motor begins to run After a short
42. Final Report for Solar Biomass Processing Sponsored by National Collegiate Inventors and Innovators Alliance NCIIA and Boeing In Collaboration with Kwame Nkrumah University of Science and Technology KNUST Version 2 0 May 19 2012 Prepared by Alexander Nolet Electrical Mechanical Engineering Henry Wettersten Nuclear Mechanical Engineering James Davis Mechanical Engineering DIS Peter Carnevale Mechanical Engineering DIS Richard Wolf Mechanical Engineering Shuai Yue Mechanical Engineering Thomas Schwab Mechanical Engineering Project Engineer Casey Goodwin Chief Engineer Mark Steiner O Page Executive Summary For the biomass project the team was able to create a working prototype This prototype consisted of four subsystems reflector reactor frame and control The reflector concentrated the sun on the reactor The reactor then used the heat from the sun to convert biowaste into biochar The control box was designed to track the sun so that that part of the process would be automated These four subsystems worked together to create actual biochar The goal for throughput was 2 Ib hour This device only made around 5 Ib hr Though this device did show that throughput was possible and when this device is used in Ghana the throughput could increase due to the change in latitude from New York 1 Table of Contents List OF FIBUFGS oisi oi L aa assaka A
43. MMENTS MATERIAL MILD STEEL iS SIZE T UBER REV AS MACHINED 4 B 2 DO NOT SCALE DRAWING SCALE 1 1 WEIGHT SHEET 1 OF 1 2 3 Note This schematic is for use as a water jet cutting reference only Do not use to machine other features 05 00 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION NEXT ASSY USED ON 5 4 UNLESS OTHERWISE SPECIFIED DI IMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH TWO PLACE DECIMAL THREE PLACE DECIMAL TERPRET GEOMETRIC TOLERANCING PER FI Mild Steel ISH Mill DO NOT SCALE DRAWING 3 BEND NAME DATE Design Lab Biomass DRAWN CHECKED TITLE ENG MEG APPR Upper Flange Q A COMMENTS vantity 1 SIZE DWG NO REV Q y A Upper Flange WJ 2 SCALE 1 2 WEIGHT SHEET 1 OF 1 2 1
44. MPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS A WHOLE FINISH B D rU WITHOUT THE WRITTEN PERMISSION NEXT ASSY USED ON lt INSERT COMPANY NAME HERE gt IS PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 1 1 WEIGHT SHEET 1 OF 1 7 5 4 3 2 1 1 3 813 983 005 THRU 4 252 THRU ALL 2 496 X 90 AX 6mm Flathead 1 625 2 1 4 000 2 624 2X 144 THRU ALL NZ 279 X 1009 FAR SIDE 2X 6 Flathead Farside 01 220 2X 0 Clearance 30 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE IS PROHIBITED NEXT ASSY USED ON APPLICATION 128 128 DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL 1 32 ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE PLACE DECIMAL 005 MATERIAL Aluminum 6061 T FINISH DO NOT SCALE DRAWING 470759 THRU ALL 6X 126 THRU ALL Q 248 X 90 6X 3mm Flathead R 25 x4 2X 070 THRU ALL 1 8 Thickness QTY 1 30 NAME DATE DRAWN RPI Design Lab Biomass CHECKED ENG APPR MFG APPR Alexander Nolet sz EscapementMountingPlate SCALE 1 1 REV 1 WEIGHT SHEET 1 OF 1 000 01 85
45. NG SCALE 1 2 WEIGHT SHEET 1 OF 1 0 625 51 125 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION NEXT ASSY USED ON DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE PLACE DECIMAL 005 MATERIAL Alloy Steel FINISH DO NOT SCALE DRAWING 010 000 2X 136 500 8 32 UNC v 330 DRAWN Design Lob Biomoss CHECKED ENG APPR MFG APPR Q A COMMENTS Alexander Nolet sz OutputCoupler_Outer SCALE 1 1 WEIGHT SHEET 1 OF 1 3 75 rm 1 10 0 188 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION 5 4 USED ON DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL ANGULAR MACH BEND TWO PLACE DECIMAL 02 THREE PLACE DECIMAL 005 INTERPRET GEOMETRIC TOLERANCING PER MATERIA Plain Carbon Steel FINISH DO NOT SCALE DRAWING 3 UNLESS OTHERWISE SPECIFIED 0 094 NAME DATE DRAWN RPI Design Lab Bioma
46. ON IN PART OR AS WHOLE FINISH B Explod ed View WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON lt INSERT COMPANY HERE gt 15 PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 1 12 WEIGHT SHEET OF 1 8 7 6 5 4 3 2 1 2 107 THRU ALL 6 32 UNC ALL UNLESS OTHERWISE SPECIFIED NAME DATE n D RPI Design Lab Biomass DIMENSIONS ARE IN INCHES DRAWN TOLERANCES FRACTIONAL TITLE ANGULAR Mach BEND ENG APPR TWO PLACE DECIMAL 02 5 8 Clomp Collor Mod THREE PLACE DECIMAL 005 MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS MATER DRAWING IS THE SOLE PROPERTY Alexander Nolet SIZE DWG NO REV lt INSERT COMPANY NAME HERE ANY REPRODUCTION IN PART OR AS A WHOLE FINISH A 6436K 1 50 Modified WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 2 1 WEIGHT SHEET 1 OF 1 5 4 3 2 1 3X 291 V 1 190 3X 7mm Clearance 1 98 1 460 Same offset distance down as Gearbox AX 150 v 130 2 1 460 C AN 150 130 AX 6 Clearance B 2 05 4 7 R 25 4X 19 64 1 0 0 1 MM Modify Existing Part 50 _ UNLESS OTHERWISE SPECIFIED E RPI Design Lab Biomass DIMENSIONS ARE IN INCHES DETAIL A TOL
47. TS MATERIA SIZE DWG NO REV 1 x 0 072 Sq Steel Tube FINISH Mil Quanity 1 B C 55 b r DO NOT SCALE DRAWING SCALE 1 8 WEIGHT SHEET 1 OF 1 3 2 1 2 38 4 28 45 09 VIEW G G SCALE 1 3 257 THRU SECTION A A 4X 26 THRU 5 16 18 UNC THRU 3 2 1 38 1 lt DETAIL D DETAIL C 1 2 SCALE 1 2 ES 5 625 THRU Duy DETAIL B SCALE 1 2 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN HBW 3 21 2012 Design Lab n Biomass TOLERANCES ANGULAR 0 5 CHECKED TITLE JP High Side INTERPRET GEOMETRIC Q A TOLERANCING PER COMMENTS s 5 MATERIAL DWG NO REV 1 x 0 072 Sq Steel Tube EM ow High Side 1 DO NOT SCALE DRAWING 3 SCALE 1 8 WEIGHT 1 SHEET 1 OF 1 48 00 e 0 406 THRU p MITER 45 EN DETAIL A SCALE 1 2 98 97 gt 90 09 DETAIL B DETAIL C SCALE 1 2 SCALE 1 2 90 09 005 2 500 Gen DETAIL D DETAIL E SCALE 1 2 SCALE 1 2 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE INCHES DRAWN HBW 3 21 2012 Design Lab n Biomass eege CHECKED TITLE ANGULAR 0 5 TWO PLACE DECIMAL 0 050 APPR THREE PLACE DECIMAL 0 005 5 rt F ra m e TOLERANCING PER TX 0 072 Sq Steel Tube DWC NO REY VU Quanity 1 B Support Frame DO NOT SCALE DRAWING SCALE
48. The reflector with the top support 58 Figure 41 Reactor top support brackets and reflector assembled 58 Figure 42 Entire assembly without the tracking system 59 Figure 43 The completed device iiie ee D eere Deo ee e RE ERR RES 59 Figure 44 Wooden mold for secure packing and maintaining reflector shape 61 45 Packed Crate i CAD uiii rc E s e e OT EE ede ERU OE WDR 62 Figure 46 Test A Temperature 5 06 2012 13 30 65 Figure 47 Test B Temperature 5 06 2012 15 03 65 Figure 48 Test C Temperature 5 07 2012 11 40 66 Figure 49 Test D Temperature 5 07 2012 L 67 Figure 50 Test E Temperature 5 12 2012 9 38 enne ener eene naa 68 Figure 51 Pre charred processed corn cobs input the reactor 73 Figure 58 Reactor Results een ente tei eto k ete veri 93 Figure 59 Glass Envelope Results mua tec e eere ee eet ee env eie ies 95 Figure 60 Reactor Insert Removal Method 97 Figure 61 Reactor Insert Resu
49. ULAR PATTERNED 6 32 TAPPED 2X 8 000 0 150 UNLESS OTHERWISE SPECIFIED NAME DATE p b B DIMENSIONS ARE IN INCHES DRAWN ni 10mass TOLERANCES FRACTIONAL CHECKED TITLE ANGULAR MACH BEND TWO PLACE DECIMAL ENG AFPR THREE PLACE DECIMAL 0 020 MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL TOLERANCING PER CONNAN THE INFORMATION CONTAINED IN THIS MATERIAL DRAWING 15 THE SOLE PROPERTY Aluminum 6061 SIZE DWG NO REV lt INSERT COMPANY NAME HERE gt ANY M REPRODUCTION IN PART OR AS A WHOLE FINISH Q U na na WITHOUT THE WRITTEN PERMISSION NEXT ASSY USED ON lt INSERT COMPANY NAME HERE gt IS PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 1 2 WEIGHT SHEET 1 OF 1 7 6 5 4 3 2 1 180 2X 1367 500 8 32 UNC 330 DIMENSIONS ARE IN INCHES TOLERANCES on RPI Design Lab Biomass FRACTIONAL ANGULAR MACH BEND CHECKED TWO PLACE DECIMAL 05 ENG APPR THREE PLACE DECIMAL 005 PROPRIETARY AND CONFIDENTIAL MFG APPR THE INFORMATION CONTAINED IN THIS QA DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY COMMENTS REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON Alexander Nolet sz ous REV lt INSERT COMPANY NAME HERE gt IS OutputCoupler_Inner PROHIBITED APPLICATION DO NOT SCALE DRAWI
50. akage Handling Manufacturing scale up Total 125 0 324 0 361 0 319 0 49 0 285 100 Page Reflector Material E E Glass Laminate oos 0 _ os 0 0 Figure 56 Reflector Material 101 Page Appendix G Thermal Analyses 445 SolAbs 45 SolAbs 93 reactor pipe selective coating Biomass M reactor insert SolAbs Q3 Glass envelope a With glass envelope b Without glass envelope Figure 57 Thermal energy schematic of receiver assembly 102 Page conduction radiation radiation AAVV 0 gt 2 AAA 3 5 AN p conduction conduction dian UT ES conduction d convection convection convection b biomass 2 reactor inner surface 5 glass envelope outer surface 0 insert inner surface 3 reactor outer surface 6 surrounding air 1 insert outer surface 4 glass envelope innersurface 7 sky Figure 58 Thermal Resistance model of Receiver Assembly 103 Table 16 List of heat fluxes in Receiver Assembly Heat Transfer Mode Heat Transfer Path q_b0_cond conduction insert inner surface biomass q_01_cond conduction insert outer surface insert inner surface q_12_cond conduction reactor inner surface insert outer surface q_12_conv con
51. budget of the entire system The large fraction of the total cost just to keep the system pointed at the sun raised doubts as to whether precious groups choice of a motor based drive was an appropriate choice As the majority of cost came from driving two alternate techniques were presented A wound spring or falling mass These concepts focused on the fact that the user must interact with the system to load and unload the biomass Therefore at a minimum of added effort by the user the tracking system can be reset The falling mass was preferable across the board First and foremost the mass does not necessarily have to be shipped with the device as the weight requirement can be satisfied by a small bucket of sand a piece of scrap metal or even a rock On the other hand the spring would have to be designed and built to last the life of the system It would have resistant to the elements or small enough to be enclosed in a container A constant torque output is preferable to a linear or higher order spring as the driving torque can sit near the rated output torque of the gearbox Thus for the reasons of cost and an unvarying input torque a falling mass was selected as the power source There is a small weight of 20 Ib attached to a single pulley A cable runs down from its attachment point on the base through the pulley on the weight and back up to a 1 5 inch drum This drum has a built in handle This handle allows for the simultaneous resettin
52. cision to maintain the timing necessary to keep the collector pointed at the sun Clockwork mechanisms have been around for hundreds of years What is less common is their ability to discontinuously actuate another mechanism with a high force with respect to the clock size The alternative was to use electrical timing Electrical timing was chosen because of its robustness Escape wheel Release mechanism Cam control Figure 32 Escapement mechanism Spring 2012 The first method for actuating the follower was a solenoid It is one of the simplest electromechanical devices The sharp actuation was desirable due to the limited travel necessary to completely disengage the follower from the escape wheel and to overcome the static friction During part selection this was deemed not a viable option because solenoids are primarily rated for 1 10 or 1 100 of the necessary force A solenoid that met the force requirement with margin mostly like exists but the large power requirement makes it uncommon and therefore not cost effective A motorized actuation was researched next 49 Page There are several choices of motor in general servomotor stepper motor and a plain motor The choice of actuating the followers with a cam lessens the precision of closed loop control of the motor A stepper motor or servo could actuate via a coupled link not traversing a full rotation However one full rotation of a cam would actuate the followers as needed Al
53. cket was constructed to hold the insert in place during processing This bracket was designed to swivel out of the way of the insert during removal Figure 24 Reactor Mounting Bracket 41 Page Figure 25 Actual reactor showing the mounting bracket 42 Page 5 3 Frame 5 3 1 Concept selection Table 5 shows the progression of the frame design through the Spring 2012 semester Table 5 Comparison of Frame Designs Featured a gear system to adjust reflector angle offsets cost Sliding Reactor Steel frame Summer 2011 Team Fall 2011 Team Fall 2011 Team Spring 2012 Prototype 1 Prototype 2 Current Design Pros Pros Pros Pros supports reflector Steel frame Communal System Least expensive design to date modular structure designed to be flat packed for easy shipping Angled amp Sliding Reflector Built in tracking system Steel frame Cons Wooden frame susceptible to extreme weather conditions Locked in place and had to be actively adjusted throughout the day Labor intensive Non modular amp Expensive Cons Locked in place has to be actively adjusted throughout the day Cons Conceptual not built or tested No angled panel Non modular Locked in place and had to be actively adjusted throughout the day Cons requires multiple people to assemble Adjusting reactor position slowly removes paint 5 3 2 Prelim
54. convection to reduce smoke and improve charcoal burn This stove is very appropriate for this design because it accepts relatively loose pieces of charcoal Figure 7 Toyola stove Image found at http www unep org unite 30ways viewimage aspx projectID 40 19 3 4 Solar Concentrator The purposed torrefaction unit employs a form of solar concentration trough style solar concentration Trough style solar concentration typically uses a large solar reflector to concentrate light on a pipe to heata working fluid contained in the pipe This heated fluid can be used for power generation or heating While the solar torrefaction unit excludes the fluid it does collect light and concentrate it on an absorber tube similar fashion to heat biomass Figure 8 Previously used solar trough used for producing electricity Image found at http thefraserdomain typepad com photos uncategorized 2007 07 28 solar_trough_3 jpg Solar concentrator design provided a wealth of data and knowledge for the design process Many concepts from these designs like solar selective coated reactors and anodized aluminum reflectors were implemented in this design This research also made the decision to use trough style solar collection much simpler because the costs and benefits were illustrated clearly in Set out the Legs Setoutthe twolegs Make sure the shorter one is facing south 20 Page Connect the Legs Lift the reflector and have a
55. ctuations 69 Page 6 3 Meeting the User Requirements Table 7 Technical Specifications with the wanted value and the actual tested value Technical Specifications Target Value Tested Value Results Necessary parts excluded parts 0 parts Number of persons required 2 persons 2 3 persons Parts require significant energy to fit 2 parts 1 part together Amount of force required to fit parts 5 Ib Meets target value Weight of heaviest part 40 Ib 25 Ib Steps for setup 3 steps Meets target value Steps for batch 5 steps Meets target value Time to set up for day 10 min 10 min Time for batch process 45 min 50 min Max pounds required 20 Ib 5 Ib Nema rating for electro mechanical Nema 5 Estimated at Nema 5 enclosures Parts that can corrode that are not 0 parts 0 parts coated with rust inhibitor Parts that move and are made of parts 0 parts corrodible material Withstands winds of 20 mph Angled toward the sun with elevation 7 5 degrees North Meets target value angle of The tracking system shall drive the 15 1 untested panel at a speed of degrees hour Error in tracking at any time does not 1 degree untested exceed Minimum component life gt 10 years Estimated to meet target value of components replaceable in Ghana gt 60 untested 70 Page
56. eaches thetop ofthe travel FillthePail with sand orrocks Every Cycle Setup Load The Insert Putthe dried corn cobs in It s easiest and most effective if they are cut up 88 Page Insert the Insert Slip the insertup into the reactor Remove Insert Usethe two hay hooks to remove the insert Unload Insert Tip the insert using the hay hooks and let the corn cobs fall out You may have to cool the insert before reloading 89 Page Appendix D Cost Analysis Table 9 Cost benefit analysis total angle change 49 715 Variation from mean 24 8575 Width feet 5 focal length feet 1 5 End area not covered feet 0 694925 in inches 8 339099 Length of reactor 3 of reactor in light 23 16416 reduced use gt negligable impact Negligible percent reactor not in light 0 1 reactor length not in light 0 3 Variation from mean 11 30993 total change 22 61986 angle change per day 0 272411 number of days in use 83 03581 Percent of days in use 0 227495 Payback change good bad Value per year 33 54647 12 57993 Cost of unit 500 500 Payback 14 9047 39 74586 difference in payback in years 10 91558 27 68986 Difference in value 366 1792 348 3364 90 Page Appendix E Expense Report Table 10 Overall Expense Report
57. eactor Centerline text 0 1 05 Reactor Surface text 0 1 FLR FL 115 Page Calculate Ray Offset function x z RayOffset D W FLR sam Points per Sweep Div 15 Num Div 200 zlimit 3 Device Parameters units in inches Reactor Diameter D 3 Collector Width W 68 Distance from FP to AoR as of Distance from FP to Base of Collector AoR 0 Focal Length FL FLR W Angles in degrees and lengths in inches 96Solar Angle Misalignment 96sam 1 Angular Parabola Error ape 0 116 Page Offset Parabola Error OPE 0 Convert Inches to reactor radius lengths and angles to radians R 0 2 r 1 w W R fl FL R aor AoR 100 fl ope OPE R sam sam pi 180 ape ape pi 180 lnit Parabola Origin at Axis of Rotation Rsam cos sam sin sam sin sam cos sam fp Rsam 0 aor a 1 4 fl aor x 5 w w Num 1 5 w 2 c True Shape TS Rsam x y 5 1 TS 2 117 Calculate Parabola Angle from Global Horizontal ArcLength 0 theta zeros 1 Num TSO zeros 2 Num for n 2 Num 1 if xp n lt 0 theta n pi atan2 yp n 1 yp n 1 xp n 1 xp n 1 else theta n atan2 yp n 1 yp n 1 xp n 1 xp n 1 end ArcLength ArcLength sqrt yp n yp n 1 2 xp n xp n 1 2 end TrueArcLength ArcLength R
58. endations include changes to the reflector and simplifying the control system The solar selective coating that the reactor is coated with may not be necessary There are cheaper alternatives to the one used that may work just as efficiently This may also allow further iterations to increase throughput by being able to increase the size of the reactor without much more cost due to less cost from the coating Also the tracking system is very complex and could be simplified This also could be altered to include a simple mechanical back up system The final recommendation for controlling the angle of the reflector is that it is acceptable to have a person move the reflector Once the prototype is actually being used in Ghana further changes can be made as well as further iterations on this design For instance the device could be made out materials found in Ghana to prevent the need for shipping This would also lower the cost of the system which is another recommendation from the team Also future teams should look into other ways than the glass tubing to implement the insulating glass idea because the glass tubing is not easily attainable in Ghana Lastly the reactor and possibly the reflector sizes could be made larger to increase throughput However with further testing in Ghana these recommendations may be found to be unnecessary Also further testing to determine these factors is recommended e The effectiveness of the glass envelope Al
59. eoprene O rings embedded into the steel reactor end caps The glass chosen for the receiver application is Schott DURAN 8330 Tubing Decision Matrix Appendix F Besides its excellent physical optical characteristics it has proven its performance in various Concentrated Solar Power applications CSP Nevada Solar One Acciona 2007 Solel Mojave Desert Project NREL 2011 A novel proposal in this semester s design is the addition of a reactor insert this insert acts as a shuttle for the biomass allowing easier and safer loading unloading and thereby increasing the throughput compared to the existing prototype Multiple at least two inserts allow the user to unload and reload a charge of biomass while another batch is running In addition to the increase in throughput this new component eliminates the deposition of char on the inside of the reactor tube which over time substantially decreases the thermal efficiency of the reactor 39 Page Glass envelope End cap with flange End cap bolts Neoprene O Rings Absorber Figure 21 Reactor end view Figure 22 Reactor both ends 40 Figure 23 Reactor Receiver Assembly with Insert 5 2 5 Final Design The reactor is suspended using mounting brackets which simplify the attachment to the reactor and allow it to slide along the reflector support to account for seasonal elevation changes of the sun Figure 24 shows a single support bracket Also a bra
60. ept Selection eh p ee Pp reet e eii HA RET ETE 28 5 1 T 29 5 1 3 Preliminary Deelen ence est 30 5 1 4 32 EEADC nqpq 34 5 2 1 Concept selection eoe e tih dette 34 522 2 Background un aaa eae ERE 34 5 2 3 aka eer quna kya Pausa e md teint 37 5 24 Preliminary 39 5 25 Final Design mau AA 41 5 3 uqu 43 5 3 1 Concept selection o Atv e i eite veniet mte 43 5 3 2 Preliminary Desien s u A Oa ay 43 5 3 3 DESIGN ua ai etae date e 46 BA Controllu a dete 48 5 4 T Concept selection u q n laa 48 E e EI 50 5 43 Preliminary DESIGN x un w aw mayo 52 5 4 4 Fi al D8 SIBn ci enero RN ER ed vos e Pei a 52 5 5 PrOCESS OF USO oerte rette us aei ee arc nce tud en RR rne d AY 57 5 5 1 Design OT WSC M 57 5 5 2 Initial ut aa dees see 58 5 523 DailysS
61. er Modified 1 3 EscapementMountingPlate Fabricated 1 4 Wheel Fobficoted 1 5 GearboxMountingPlate Modifed 1 6 SolarPanel OTS 2 7 OTS 1 8 6436 15 OTS Mcmaster 1 9 9489 45 OTS Mcmaster 2 10 Shaft Input Fabricated 1 11 CircuitBoard Fabricated 1 12 LimitSwitch OTS Mouser 1 13 Fobricoted 1 14 OutputCoupler Outer Fabricated 1 15 OutputCoupler Inner Fabricated 1 16 ShaftsealMountandBearing Fabricated 2 17 ShearDisc Assy Fabricated 1 18 InputCrankHanale OTS Mcmaster Modified OTS 19 SolarPanelRibSpacer 4 20 SolarPanelandPulleyMount Fobricoted 1 21 ShaftCoupler OTS Mcmaster 22 Follower Right Fabricated 1 23 Follower Left Fabricated 1 24 CatchBlock Fabricated 1 25 BushingFollowerRight Fobricoted 1 26 BushingFollowerLeftSpacer Fabricated 1 27 BushingFollowerLeft Fabricated 1 28 Switch OTS Mouser 1 29 BushingFollowerRightSpacer Fabricated 1 30 Fabricated 4 31 BNA4100806CH Modified Modified 1 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN RPI Design Lob Biomoss TOLERANCES TITLE FRACTIONAL CHECKED ANGULAR MACH BEND TWO PLACE DECIMAL ENG APPR THREE PLACE DECIMAL MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS ali COMMENTS MATERIAL DRAWING IS THE SOLE PROPERTY OF SIZE DWG NO REV lt INSERT COMPANY HERE ANY REPRODUCTI
62. etu p nete E mban 60 5 5 4 60 5 6 Mantifacturing and Shipping eene cete 61 5 6 1 ee OI 61 516 2 5 aaa A 62 Final Design Evaluation tore rette eO ee 63 6 1 Experimerital Desigh i cepere Dee ED DEAN WR 63 6 1 1 Testing procedure for temperature measurement in actual system 63 6 1 2 Testing procedure for testing spot temperature measure and record 63 6 2 Results and Analysis u e ee 64 EN Falle En EE 64 6 2 2 ua Sula neca 65 6 2 3 Gontrol Power u e 68 6 2 4 Drivetrain Testing gedd 69 6 3 Meeting the User Requirements 70 7 COMCIUSIONS Z yz eum TK 72 IUDICI 72 References iu ee eei dte tu Eden 75 Appendix A Customer Requirements 76 Appendix B Test Plans ii aim emet pete eee tea ia i es 80 User nas 84 Appendix D Cost
63. forward 60 Page 5 6 Manufacturing and Shipping 5 6 1 Manufacturing For simplicity most components of the solar collector were built from 1 in x 0 072 in square steel tube The parts that comprise the machine frame were cut to length properly mitered all mounting holes drilled and were then welded together The ribs were sent out to be laser cut from 0 125 in aluminum plate This ensured that the geometry was correct to within the tolerances of the machine used 0 005 in and provided a clean square edge to which the Alanod backer was attached This ensured the parabolic geometry was correct To ensure proper adhesion and good contact between the Alanod backer and the aluminum ribs a wooden negative of the parabola was cut from a sheet of 0 75 in plywood By spacing out five of these plywood ribs a form was created in much the same way as the reflector itself During gluing the form was used to support the reflector sheets and resist their desire to peel away from the ribs while the adhesive was curing Figure 44 Wooden mold for secure packing and maintaining reflector shape 61 Page 5 6 2 Shipping A crate was designed to fit the system while remaining as compact as possible The crate needed to be certified to be shipped internationally this meant that the crate need to be stamped with heat treated wood stamps to easily show that the wood used was heat treated The crate fits the disassembled device with t
64. g of the falling mass and the collector to East The drum is attached to an axle which passes through a shaft seal a sleeve bearing and finally the side wall of a GI 50 Cal Ammo Box The shaft seal limits contaminants into the sleeve bearing and or the tracking container This input shaft continues into the box and through the input side of a 60 1 right angle worm drive gearbox Attached to the input shaft inside of the container is an escapement wheel pictured below The escapement wheel allows the user to crank the panel back to the East each morning during the setup of the system During this operation the followers simply spring out of the way Conversely the followers hold the wheel in placed against the torque provided by the drum and weight 48 Page The followers are actuated once every four minutes the escape wheel moves 60 degrees each actuation Through the gear reduction this results in a panel movement of 1 degree This keeps the panel moving at an average speed matching the sun 15 degrees hour While a fully mechanical clock could easily keep time this is a challenge to the actuation of the escapement With the proposed rated torque there is 5 16 of friction on the head of the follower There were two main considerations for the possible selection of a fully mechanical timer and actuation part replace ability and reliability A mechanical clock would increase the number of mechanical components These components require pre
65. g them safe from heat The system also requires you to stand back while loading because of the angle which should keep most people out of the sunlight 57 Page 5 5 2 Initial Use The initial set up is the assembly of the system After the system arrives the users will remove it from its crate This was designed to not require any significant effort or skill on the part of the users For example the upper supporting frame connects to the reflector via four bolts in the corners of the reflector and a wrench is included in the crate Figure 40 The reflector with the top support After the Reflector and supporting frame are together the reactor can be mounted to the frame To do this the two brackets must be slipped over the upper supporting frame and the reactor must be tightened using a hex wrench to these brackets Based on testing it seems this can be done with one person but it s much easier with two Figure 41 Reactor top support brackets and reflector assembled 58 Page Then the reflector and supporting frame should be lifted and the legs struts should slide on either side The bottom bar should be tightened using two hex nuts Two to three people are required for this step one for each side and one to tighten the bottom support Figure 42 Entire assembly without the tracking system The tracking assembly slides onto the higher strut with the couple over the axle Four screws should be tightened to hold the trac
66. ge The second test evaluates how well the motor can actuate if the solar panels are providing no power to the system This is an extreme case Even with the sun behind a cloud the panels will be providing a modicum of power The conditions of the test are as follows The capacitor bank was fully charged using the Bench top supply XXX The motor control was bypassed so that the motor would run continuously The supply was turned off and a timer was started The motor completed 4 revolutions before the stored voltage read 8 45 Volts This voltage corresponds to the 50 power level The motor continued to run after this albeit at a much less energetic pace There is little confidence that the motor can consistently actuate the system at or below the 50 power level The results of the testing are favorable The conversion of biomass requires substantial solar power The system can fully charge in between actuations if the panels operate at 50 power This be assumed to be likely on average if biomass is being successfully converted If a cloud or other obstruction limits the power being gathered by the device several actuations can be performed without added power input It is highly unlikely that the system will be unable to actuate itself if there is adequate solar power to convert biomass In the event of a single missed actuation the solar misalignment will cause 10 of the concentrated light to miss the reactor This is fault is not high
67. gle 7 5 degrees for Ghanaian north Latitude Design to track the sun Tracks continuously Maximum angular error 1 degree Tracks accurately Maximum difference in angle 2 degrees between reflector and sun Long lasting Lasts long enough to pay for Limit areas of wear minimum component life gt 10 years itself Use only long lasting components Prefer repairable of components replaceable gt 90 simple components in design in Ghana 13 Page Customer Requirement Technical Requirement Approach Technical Specification Target Value Low cost Ghanaian farmers can receive Reduce number of Price lt 5800 loan grant for enoughto buy components system Use inexpensive components Payback Period lt 10 years Creates biochar creates biochar for use Design reactor to Biomass converted per hour 2 lb hr hold sufficient biomass Achieve Sustains operational 320 degrees torrefaction temperature temperature safe The system does no harm to Limit ability to look Amount of solar intensity that lt 1 sun farmers or their neighbors and into reflector bystanders are exposed to families Amount of times you have to 0 times look at the reflector to use device Does not require Amount of time required to 0 minutes contact with hot components touch a surface capable of burning Many of the requirements of the system are presented in Table 1 User Needs in the customer needs
68. hay hooks and let the corn cobs fall out You may have to cool the insert before reloading Appendix D Cost Analysis 25 Page 4 Professional and Societal Concerns When reviewing the project the team considered economic social political safety and environmental issues 4 1 Economic Based on the personal income statistics of Ghanaian farmers found by the Fall 2011 Biomass team in order to purchase the designed solar torrefaction unit Ghanaian farmers would likely have to take out a loan and pay back the savings from using the unit This adds an additional level of complexity because of the scarcity of loans in Ghana the severity with which debtors can be dealt with and the interest rates charged Furthermore it separates Ghanaians from a part of their market place If this type of solar torrefaction device were widely disseminated the demand for local charcoal would be reduced This could cause local charcoal trade within the country to slow Ideally it would help Ghanaian farmers and reduce deforestation However this system could hinder traditional charcoal manufacturers and their employees 4 2 Environmental Because this system allows for alternate less expensive streams of biomass to be used wood from deforestation will be less valuable It is hoped that this will reduce the amount of deforestation and slow the increase in dust by maintaining the natural barriers to wind and soil erosion and reduce poten
69. he parts carefully stacked to minimize the space needed to pack the device The packing was also planned so that the pieces will be secure during shipping The wooden mold shown in Figure 44 used in the construction of the reflector will be placed in the crate to support the reflector The reactor and the control box will be secured to the mold to keep them from moving due to their fragility The rest of the pieces will be placed around the wooden mold Shipping to Ghana is straightforward and the team determined that export controls would not be an impediment The actual shipping costs are going to be covered by the project sponsors Figure 45 Packed Crate in CAD 62 Page 6 Final Design Evaluation 6 1 Experimental Design 6 1 1 Testing procedure for temperature measurement in actual system Objectives measure the precise temperature change vs time during the torrefaction process of the actual built system To determine the ideal cook time of biomass to reach the desired characteristic of torrified char the throughput produced at different parts of the day determine the effectiveness of the glass on the reactor To determine the role that particle size has on throughput See Appendix B for list of materials and testing procedure 6 1 2 Testing procedure for testing spot temperature measure and record Objectives e measure the local testing spot temperature while the testing f
70. in the budget constraints Moreover all of the proposed designs were focused on achieving reactor temperatures appropriate for flash pyrolysis Temperatures gt 340 C This has been deemed unnecessary because the team is no longer considering biogas or biooils as end products For the chemical conversion of biomass to char a range from 250 C to 300 C the temperature range for torrefaction is sufficient This semester s design the culmination of two years of work focuses on maximizing thermal efficiency in order to minimize footprint and shrink the payback period 34 Table 4 Comparison of Reactor Designs Less radiative and convective losses Reflects radiative losses back to absorber Increases radiative absorption area Fall 2011 Fall 2011 Team Fall 2011 Team Spring 2012 Concept l Concept 2 Concept 3 Current Design Double glass Silvering Glass Threaded Absorber insulation Pros Pros Pros Pros Least expensive design to date Selective Coating maximizes solar absorption w protective clear coat High transmission durability glass Glass protection end caps bars above receiver Insert increases throughput amp lifetime no deposition on inside of absorber Cons Expensive Purely Conceptual not implemented or tested Double walled insulation unnecessary Can t be operated by one person Cons Costly gt 3
71. inary Design The preliminary frame concept and the accompanying A frame concept were initially hand sketched Figure 26 Figure 27 These drawings served as the basis for the development of future design alterations and CAD implementation 43 Page x 1250 mm 400 Box Me thickness 600 Gf Keccbor conma um d egual d 53 apor 1 Figure 26 Reflector Sketch Spring 2012 2 sa pet ale T view 55 50 99 e 3 8 kel d Stage box ex let C 09 Figure 27 A Frame Sketch Spring 2012 44 Page To account for seasonal elevation changes of the sun the reactor must be able to shift its position axially Without this possibility a large portion of the light misses the reactor during certain times of the year A bracket was designed that uses the existing bolt pattern of the receiver end caps to attach itself to the assembly The bracket rests on square tubing passing over the receiver IN I gt AND L gt v ON NW dra v Na Ces p 4 2 Figure 28 Reactor bracket Sketch Spring 2012 45 Page 5 3 3 Final Design After some consideration the frame structure was redesigned to be lighter and easier to manufacture This thought was then carried through all other areas of the device which resulted in the current design shown
72. ion Availability in Ghana Total 100 0 38 0 54 0 28 94 Page Glass Envelope 0 6 0 5 gt 0 4 E 0 3 0 2 D 0 am Figure 53 Glass Envelope Results 95 Page Table 13 Reactor Insert Removal Method Matrix RI Cat Wt p Threaded Pole Hay Hook Double Hay Hook Umbrella Spear Ball Detent Spear Permanent Handle ___ Direct risk Indirect risk Ease of use Intuitiveness Ease of production Total 100 0 22 0 27 0 23 0 23 0 15 96 0 3 0 25 5 gt 0 2 5 0 15 0 1 Ki 8 0 05 0 m Production level B Ergonomics B Safety B Cost Reactor Insert Removal Method Figure 54 Reactor Insert Removal Method Results Threaded Pole amp Double Hay Ball Detent Permanent Hay Hook Hook p Spear Handle os o o 97 Page Table 14 Reactor Insert Matrix Material Cost Weight Required manpower Safety Thermal Conductivity Specific Heat Ease of production Availability in Ghana Total 100 0 35 _ 0 51 0 44 98 Page Reactor Insert gt 5 E wn Figure 55 Reactor Insert Results 99 Page Table 15 Reflector Material Matrix Cat Wt Flabeg Thick Glass 5 Glass ReflecTech Laminate All Polymeric We E s Durability Bre
73. king system in place and the coupler should also be tightened with two hex bolts One person can do this with relative ease and the process is not complicated Then a bucket filled with sand should be hung from the on the tracking system It s best to have the weight 20lb but it does not need to be exact Figure 43 The completed device 59 Page 5 5 3 Daily Setup It s easiest to remove the bucket attached to the tracking frame first although not required Then the user needs only to turn the crank until the shadow of the reflector lines up with the line on the reflector The bucket of sand can be put back on and the system should run throughout the day It is preferable to do this 15 minutes before one begins to use the system to allow it to heat up 5 5 4 Cycle Setup In order to use the system one must have laid out and dried corn cobs beforehand It s best although not required that these cobs be cut into small pieces These pieces should be dumped into the insert tube The tube can then be loaded into the reactor It s important to wait for some 30 minutes after small amounts of smoke are released some 45 minutes on average After waiting 45 minutes one can use one of the hay hooks to remove the tube and the other to help hold it The biochar can be dumped out into a bowl towel or onto the ground with a slight knock Then let the tube cool for 2 4 minutes and repeat the process The process is quick and straight
74. l that is needed is to turn the motor on and off when it completes its rotation DC motor was preferable to a stepper or servomotor for cost reasons A limit switch provides the necessary feedback From the start of the design of the mechanism there was only the minimum of one follower The transition from a quick actuation to a slower one raised the concern of the follower not catching the escape wheel There is a large degree of uncertainty as to whether or not this is actually an issue It requires knowledge of the acceleration of the escape wheel The escape wheel is accelerated by gravity but retarded by friction in countless areas as well as the inertia of the system order to add reliability an additional follower was added It is actuated out of phase of the first follower The reliability of the mechanism is just as important as the tracking accuracy If the tracking misses an actuation the collector the amount of that move 1 degree will be added to the existing misalignment Verifying that the mechanism catches reliably is a key testing area for the tracking system 5 R13 R14 5k AOTOR DC 1 2 Ge System ON OFF MG1 TR ook 21 4 3 4 5 PRE SE ru 5 CONTROL SE THRESHOLD 5 10000 1 Cell DISCHARGE EN 0 3 10 2 7400 U22A TCLOSE 5 7410 1 Limit Switch
75. lts 99 Figure 62 Reflector Material c e er RE Ra EE ER NR 101 Figure 63 Thermal energy schematic of receiver assembly 102 Figure 64 Thermal Resistance model of Receiver Assembly enne 103 Figure 65 Reflector error analysis 108 Figure 66 Reflector focal length analysis 108 Figure 52 Complete CAD Model of the device 122 Figure 53 Reactor Receiver with Insert ener s nnne 122 Figure 54 Reactor View rere EET sustain 123 Figure Reactor both ends 123 Figure 56 Reactor Mounting Bracket rere 124 Figure 57 Reflector CAD image ere 124 List of Tables Table 1 User E E 13 Table 2 Project history table 15 Table 3 Semester Objectives with the matching final outcomes 17 Table 4 Comparison of Reactor Designs u 35 Table 5 Comparison of Frame Designs iuret 43 5
76. ly we would ve like to test biomass cut at various equal measurements and not just cut randomly Figure 51 Pre charred processed corn cobs input to the reactor Packing density the correlation between the amount of biomass and pyrolysis time char quality fact be linear Some variables to test this could be full when inserting biomass 50 25 etc Possibly adding low density fillers such as corn husks Chemical Composition Before After o analyzing the bio gas that is output chemicals and flow rate 73 Page e Char characteristics Energy content actually use it to cook pH and nutrients o Moisture content 74 References Acciona Acciona North America Online 2007 http www acciona na com About Us Our Projects U S Nevada Solar One AET Solar AET Solar Report 2011 Asiedu Bondzie A Ayensu and V Solar drying with convective self flow and energy storage Journal Solar and Wind Technology 1986 pp 273 279 Edward S Lipinsky James R Arcate and Thomas B Reed Enhanced Wood Fuels Via Torrefaction Online Argonne National Lboratory 2002 Feb 1 2012 http www anl gov PCS acsfuel preprint 20archive Files 47_1_Orlando_03 02_0071 pdf GNA Government of Ghana Official Portal Online Government of Ghana Official Portal 2011 http www ghana gov gh index php option com_content amp view article amp id 6316 ghana wins fi
77. ly flexible Diameter 5 089 350 159 656 4 40 UNC 220 10 32 UNF 500 lt gt 0 25 This step doesn t have to be consistent across parts The narrower Tapped Depths are approxiamate width at the face is what s inmportant UNLESS OTHERWISE SPECIFIED NAMES GATE DIMENSIONS ARE IN INCHES DRAWN TOLERANCES FRACTIONAL CHECKED TITLE ANGULAR MACH BEND TWO PLACE DECIMAL ENGIARER THREE PLACE DECIMAL MFG APPR INTERPRET GEOMETRIC QA PROPRIETARY AND CONFIDENTIAL TOLERANCING PER COMMENTS THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG NO REV DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY gt ANY ws Cir amp uitBoardStandoff WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON INSERT COMPANY NAME HERE IS APPLICATION DO NOT SCALE DRAWING SCALE 1 1 WEIGHT SHEET 1 OF 1 PROHIBITED 5 4 3 2 1 1 750 1 600 00 156 THRU O O i 0 075 2X e UNLESS OTHERWISE SPECIFIED NAME DATE H DIMENSIONS ARE IN INCHES DRAWN Design Lab 7 Biomass TOLERANCES TITLE FRACTIONAL CHECKED ANGULAR BEND ENG APPR TWO PLACE DECIMAL THREE PLACE DECIMAL 020 APPR INTERPRET GEOMETRIC QA PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS EE COMMENTS MATERIAL DRAWING IS THE SOLE PROPERTY OF Aluminum 6061 SIZE DWG NO REV lt INSERT CO
78. ned during both tests As shown by the trend of the graph before the thermocouple stopped reading temperature accurately the temperature would have continued increasing to around 300 Celsius during both tests C and D Regardless the tests from the second day proved that the glass is very effective for heating up the system and the biomass compared to the tests performed without the glass For the tests performed without the glass the temperature of the inside corncob was 43 lower than the test with the glass The glass improves the system performance on heating the corncob by 43 This is due to the fact that the use of the glass reduces the effect that the ambient air temperature and wind has on the reactor performance Looking at the results of these two tests the actual readings are very similar the tested corncob reached 226 Celsius at 1547 seconds for test C and it reached 226 Celsius at 1537 seconds for test D In conclusion the use of the glass around the reactor improves the system performance verifying the necessity of this component to increase throughput 67 Page 350 300 250 200 Outside Tube Temp vs Time 150 Temerature C Corn Temp vs Time 100 50 0 500 1000 1500 2000 2500 Time Sec Figure 50 Test E Temperature 5 12 2012 9 38 After successfully fixing the issue with the temperature readings the team ran another test again Figure 50 shows the temperature of
79. ng that was performed to ensure the performance of the device Engineering specifications will be discussed to prove the repeatability and performance of the device Finally recommendations by the design team for the future of this project will be illustrated in the conclusion 1 2 User Needs and Problems Addressed The end users of this product will be Ghanaian farmers and their families In particular the prototype is being created for corn farmers outside of Kumasi located in southern Ghana The NCIIA the primary sponsor is interested in providing a technology that provides value to these users While the prototype is designed to use some of the abundance of agricultural waste of southern Ghana it is anticipated that it could also be implemented in northern Ghana where deforestation for charcoal production and desertification are a large issue Although the device has been tested with dried corn cobs any other dry lignocellulose biomass corn stover sugarcane bagasse or banana stems can be used for torrefaction purposes From this customer review a number of important customer requirements have been identified which are summarized in Table 1 A User needs chart containing justification and methodology can be found in Appendix A Because it is designed to tackle poverty the most important features of this device are cost lifetime and yield While the specifics of these requirements are elaborated in Error Reference source not found
80. ng the funnel and seal the bag shut Wipe off any residue in the bowl with the rag Conduct the experiment again time repeating steps 1 to 17 with the inside thermocouple recording the temperature inside of a corn cob Conduct the experiment 1 more time repeating steps 1 to 17 with the protective glass tube in place to determine the difference of the effectiveness of the system Save the data acquired Make an Excel spreadsheet to plot the results 82 Testing procedure for testing spot temperature measure and record Objectives Tomeasure the local testing spot temperature while the testing for temperature measurement in actual system is proceeding Material e Using thermostat that is used for the reference temperature when calibrating the thermocouple module e Tape e Achair or small table with similar height of the reaction of the system e laptop with Excel Procedure 1 place a chair or table next to the system to place the equipment on 2 Place the thermostats on the table surface and tape the wire tip at the specific locations 3 Startrecording the thermostat readings with LabView when the testing starts 4 Record the temperature every 5 minutes during the operation 5 When the test is complete stop recording with the thermostat 6 Repeat steps to 5 when the next test begins 83 Appendix C User Manual User Manual stuff The Crate Arrives The entire assembly should ar
81. nstructed Wire the thermocouples and the modules with data acquisition board Create the appropriate program in LabVIEW to be able to measure and record temperatures Test the program and the thermocouples by measuring surrounding temperature and the temperature when the thermocouples are gripped in hand If the thermocouples are working the temperature reading will be warmer when the thermocouples are in hand Make sure the noise in the readings is within acceptable fluctuation range Put the 4 thermocouples respectively at o In between the outer reactor tube and the insert o Inside the insert Fix these thermocouples at the desired location Load copper insert with one pre made group of corn cobs and place the insert into the reactor 10 Record the time the insert was placed into the reactor on the sandwich bag labeled A 81 11 12 13 14 15 16 17 18 19 20 21 Start immediately recording the temperatures readings by turning the module on and start recording with the LabVIEW program and set it to take one measurement per second for 1 hour After 1 hour stop recording with LabVIEW and turn off the modules Remove the thermocouples Take the insert out of the tube using the hay hooks carefully place it on the ground and allow it to cool Once the insert is cool empty the its contents into a bowl When the processed biomass is cool to the touch brush it into the sandwich bag usi
82. o bending closing and opening of the parabola decreases Bending in the ribs of the collector will result in angular misalignment unless the rigidity of the ribs is increased as well Decreasing the focal length ratio also increases the surface area of the collector for a given width and length Both of these factors increase material costs To compromise on the factors discussed a focal length ratio of 0 3 was selected 29 Page The solar angle misalignment is a sum of three parts divided into two categories offset and speed Consider the following scenario that illuminates angular offset The best that the user can set the panel azimuth to is the precision of the discontinuous movement amount of the tracker During tracking the system waits then moves the panel a specific amount this is the maximum variation during tracking Assuming that the tracker is moving the same average speed as the suns travel through the sky the maximum error is twice the precision of the tracking system The precision was selected to be 1 degree In this case twice this value results in 25 of the incident light missing the reactor The remaining requirements are not as exact as those just described The device should be usable by an individual This limits the weight and by extension the length of the reactor inserts Several address the ability of the system to be assembled by two or three people with hand tools The remaining requirements attempt to address the life
83. off the ground as shown in Figure 5 the code can be found in Appendix These optimizations allowed the group to determine the width length and focal length of the reflector 30 Page Incident Light on Reactor for Various Focal Length Ratios at 2 Degrees Angular Error 15 Reactor Surface S Reflected Light Ray Offset from Reactor Centerline Reactor 30 20 10 0 10 20 30 Collector Width distance normalized to reactor radius Figure 11 Analysis for parabola optimization generated by a Matlab Script shown in Appendix H Based on these results the geometry was modeled and then integrated into the rest of the assembly as shown in the figure below Figure 12 Reflector preliminary design 31 5 1 4 Final Design The rib sandwich idea presented in Figure 12 above was attractive because it required no penetrations through the reflective surface but would have been difficult to assemble in order to assure proper reflector geometry because they upper and lower ribs must be loaded against each other to pinch the reflective surface thereby inducing unwanted strains which will cause error the parabola s geometry In order to overcome this problem the top set of ribs was done away with and the bottom ribs strengthened In order to attach the reflective surface to the bottom ribs with a minimum of geometry damaging force a weather resistant adhesive tape was applied to
84. ood can be described as a mild form of pyrolysis at temperatures typically ranging between 200 to 320 C During torrefaction the biomass properties are changed to obtain a much better fuel quality for combustion and gasification applications Westenhaus 9 Page 1 Introduction Fires roar along the side of rural roads in Ghana after harvest as farmers burn away the useless parts of the crop For most of these farmers going to the market to buy charcoal is a painfully expensive ordeal that is forcing Ghana s continuing deforestation To support these farmers and Ghana s economy and ecology a solar powered charcoal maker is being designed by the biomass group that will take the useless part of crops and turn them into valuable charcoal Figure 1 A Ghanaian farmer watching dry brush and agricultural waste burn The system works by using sunlight available during 6096 of the year to heat the biomass in a closed container at near 300 C for 45 minutes This turns the biomass into charcoal which can be used in a number of stoves particularly the newly popular Toyola stove which reduces charcoal required and smoke released This project has been developed in the Design Lab since Fall 2010 with more detail on what every team worked on presented in the Project History section These teams have established the need and viability of this project in Ghana They have also provided proof of concept in the form of working prototypes This semester
85. or temperature measurement in actual system is proceeding See Appendix B for list of materials and testing procedure 63 Page 6 2 Results and Analysis 6 2 1 Throughput Table 6 Test Results ma emay 6 7 2 7 2 7 1 15 1645 bin and Halved 5 and Halved 5in and Halve TESTEN N Percent Reduction 7 06 6 85 55 56 44 87 Tests A and B yield no char The biomass did come out more burnt but the charring was limited to the surface Tests C D and E achieved the most success Tests C and E produced the most torrified throughput and was completely black in color Although the output of Test D was similar the biomass still had a dark brown core From the data it is clear that different variables have a greater effect on throughput The most noticeable is the glass envelope With the glass on tests C D and E yielded much greater results in char temperature and percent reduction compared to the test conducted the day before without the glass Another key aspect of the testing was the time of day in which the experiment was performed The experiments that were conducted earlier in the day 13 30 and 11 40 yielded better results than the tests that followed later in the day 15 03 and 14 53 respectfully Unfortunately the team did not get the opportunity to experiment accurately with different pa
86. ork Done Work Carried Over Fall 2010 Review Ghanaian Project purposely Initial Problem Charcoal Industry statement and user groups Spring 2011 Research Ghana Business plan general General Research Analyze Bio oil purpose business Plan build Prototype research Bio oil research Summer 2011 group 1 Build a Solar pyrolysis New Prototype Troth shape and basic see Figure 4 Prototype prototype concepts Summer 2011 group 2 Test and build tracking Some testing results Concepts for testing see Figure 4 system for past showing feasibility and information on tracking prototype atracking system accuracy requirements Fall 2011 Analyze previous Dehydrating design Established feasibility of See Figure 5 designs and work briquetting prototype dehydrating and light analyze reactor and design dehydrating and briquetting processes and new business plan weight frame 15 Page Figure 5 CAD Model of Proposed Device Fall 2011 1 5 Other Relevant Information The weather patterns in Ghana were considered during the design process Ghana experiences Sarmahatten a period of extreme dust and wind where visibility is greatly reduced and dings scrapes and dust coating of the reflector may occur At the same time Ghana is very cloudy but even with cloudy skies there is still enough solar radiation to operate the solar torrefaction unit Based on several solar analyses of Ghana the reactor
87. risk due to its probability and magnitude 6 2 4 Drivetrain Testing The backlash of the panel drive unit is important because it influences some error that the tracking system can exhibit If there is a gust of wind strong enough and in a direction to turn the panel slightly the solar misalignment angle could be increased During testing of the collector without the drive the wind conditions did not manage to move the collector significantly despite friction in the bushing were the only restraint To test the backlash under a typical condition 20 Newtons down were applied the one edge of the panel The solar misalignment angle was noted 20 Newtons down were applied to the opposite side of the panel The difference of the two solar misalignment angles is approximately the backlash The method used for fine calibration of the tracking system and for verifying the tracking speed drift were the same The tracking system was setup with the drum fully wound with rope The device was supplied external power if necessary The height position of the weight was noted The time was noted and the system turned on After several hours the time and position of the weight were noted The weight should have moved Total Time _ Total Time L IT 5T inches Actuation Time 4minutes Ifthe corresponding number of actuations was out of specification then dip switch SW3 can be adjusted to increase or decrease the wait time between a
88. rive a single crate Make sure crateis near where you wish to set up the device Pry the crate open using a hammer or crowbar Connect the Top Frame Setthe top support frame on the reflecto such that the 84 Page Set out the Legs Setoutthe twolegs Make sure the shorter one is facing south Connect the Legs Lift the reflector and havea friend connect the axelsto the twostruts Put one washer on either side and connect nut Attach the Cross Bar Puta bolt through the bottom cross bar and connect a nut 85 Page Slip the Reactor Barket On One bracket onto the top cross bar Lift the reactor into line with the bracket Adda screw in each of the holes Slip the other bracket in without letting go of the reactor and screw it in 86 Page Connect the shaft to the frame Line up the four mounting studs and drive shaft Slide power assembly onto frame Use XX T Handle to tighten the two screws in the shaft coupler Putthe 45 16 Locknuts onto the mounting studs Tighten with 1 2 Inch Wrench Daily Setup 87 Page Daily Setup CompletelyUnwindthe Rope fromthe drum ThreadtheRopethroughthe Pulley onthe box ThreadtheRopethroughthe Pulley onthe Weight Pail TietheRopeto theLeft the Box so that the Weight Pail is just off the ground Byhand looptherope around the drum until the Pail r
89. rst prize at the worlds leading green energy awards amp catid 28 general news amp ltemid 162 NREL Concentrating Solar Power Projects Online 2011 http www nrel gov csp solarpaces project_detail cfm projectID 109 Prins Mark Jan Thermodynamic analysis of biomass gasification and torrefaction Report 5 1 Eindhoven Technical University 2005 Wahab Suraj Ashden Sustainable Solutions Online Ashden 2011 http www ashden org blog toyola brilliant african stove business realising big plans Westenhaus Brian New Energy and Fuel Online http newenergyandfuel com http newenergyandfuel com 2008 11 19 torrefaction E2 80 93 a new process in biomass and biofuels 75 Page Appendix A Customer Requirements Table 8 Full Customer Requirements Table Customer Requirement Technical Requirement Approach Type Technical Specification Target Value Justification Testing Easy to Assembly A Ghanaian farmer can assemble the system All parts needed included Necessary parts excluded 0 part s Hidden costs or shipping something that doesn t work will be confusing and frustrating and may cause them to abandon the device Parts fit together easily Number of persons required 2 person s The product should not be so bulky a large number of people are required but is likely that 2 people will available Age of persons required 13 50 years
90. rticle sizes The two tests that had the cut up corn cobs smaller particle size did produce better results however this is most likely due to the glass being installed 64 Page 6 2 2 Temperature Outside Temp o 5 c 5 Inside Temp 1000 Time Second Figure 46 Test A Temperature 5 06 2012 13 30 Outside Temperature C Inside 1000 Time Second Figure 47 Test B Temperature 5 06 2012 15 03 65 Page The ambient temperatures of tests A and B were 21 Celsius and 23 Celsius respectively This testing was for the system which included the reflector frame and reactor at that time The glass was not placed around the reactor tube for these first two tests As seen above the inside temperature of test A represents the temperature inside the insert and the outside temperature represents the temperature between the reactor tube and the insert The reactor tube eventually reached 178 Celsius and the insert reached 148 Celsius during this 1 hour test For the second test the inside readings represent the temperature inside of a corn cob inside the insert and the outside again refers to the temperature between the insert and the reactor tube This 1 hour test brought the inside of corncob and tube outside surface up to 152 Celsius and 200 Celsius The outside readings of both tests represent the temperature of the same location so comparing
91. s APPR THREE PLACE DECIMAL 005 MFG APPR INTERPRET GEOMETRIC Q A PROPRIETARY AND CONFIDENTIAL TOLERANCING PER THE INFORMATION CONTAINED IN THIS COMMENTS MATERIAL DRAWING IS THE SOLE PROPERTY OF SIZE DWG NO REV lt INSERT COMPANY NAME HERE ANY GearboxMountingPlate REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON Bam TUO Ne APPLICATION DO NOT SCALE DRAWING SCALE 1 2 WEIGHT SHEET 1 OF 1 5 4 3 2 1 0 25 1 50 o9 4 00 Fillet Corners On Sander 0 201 THRU ALL 025 2 0 201 THRU ALL 1 4 20 UNC THRU UNLESS OTHERWISE SPECIFIED NAME DATE RPI Desi Lab Bi DIOM DIMENSIONS ARE IN INCHES DRAWN 5 55 TOLERANCES FRACTIONAL CHECKED TITLE ANGULAR MACH BEND TWO PLACE DECIMAL 02 ENG ATE THREE PLACE DECIMAL 010 MFG APPR INTERPRET GEOMETRIC QA PROPRIETARY AND CONFIDENTIAL 5 TOLERANCING PER COMMENTS THE INFORMATION CONTAINED IN THIS SIZE DWG NO DRAWING 1 THE SOLE PROPERTY Aluminum 6061 Alexander Nolet 12254 20 InputCrank WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION DO NOT SCALE DRAWING SCALE 1 1 WEIGHT SHEET 1 OF 1 5 4 3 2 1 1 625 2X 1 169 2 0 331 1 500 0 020 00 625 0 000 THRU 2 6691 4 000 50 236 THRU AN UNIFORMLY CIRC
92. setup involves removing the device from the crate and assembling it to a usable state Daily set up is what must be done to use the system for a day Cycle set up occurs multiple times each day and involves the loading and unloading of each batch 5 5 1 Design of Use The goal for usability was that the system be simple and quick to use so as to gain acceptance in Ghanaian society The most time intensive action is the initial setup This is outlined in the User Manual in Appendix C The system set up for the day is simple requiring that the user simply turn a crank to rotate the reflector back into starting position It is clear when it is starting position because the shadow of the reactor and its supports fall on a black line In order for the reactor to be easily rotated the bucket should be removed and reattached This step is not imperative but it should be easily remembered when it is difficult to turn The crank was placed on the high side so that it s less likely that someone could be flashed with sunlight while correcting position The process of loading and running a cycle was designed to be simply requiring no more than loading and unloading returning approximately every 45 min to repeat the process The loading occurs on the lower side and the system is lower to the ground so that you need not lift anything high off the ground Hay hooks were made to resist the heat and they provide the user a lot of control while keepin
93. signal This is connects to a 24 bit clock divider U2 The divider outputs seven signals the clock input divided by 218 219 224 These signals range from 15 Hz to 2 Hz Each of these signals is connected to a pin on a seven pin DIP switch SW2 SW2 is used as to select an appropriate usable signal In typical operation just one switch is set high The output side of SW2 is wired together and connects to 12 bit and 7 bit counters U3 and U4 respectively U3 is used for the principle timing of the device U4 is used as an override for the limit switch Each of the 12 outputs of U3 connects to a pin on dip switch SW3 through a resister to regulated 5 Volts and to an input of an OR gate Each of the OR gates U5 U6 and U7 allow for the selecting of number of the 52 Page counting Since the other side of SW3 is connected to ground when it is ON that bit is active during counting otherwise it is masked With the switch OFF the input to the OR gate is pulled HIGH the output of any input OR ed with HIGH is HIGH Each output of U5 U6 and U7 connect to 13 input NAND Gate 08 Because there are 12 outputs from the OR gates and 13 Inputs one is doubled up 08 connects to inverter U9 When this signal goes HIGH many things happen in quick succession This trigger resets U2 U3 U4 the clock divider and the counters Since the 12 bit counter is reset the reset propagates through the OR gates NAND gate and inverter This trigger is only HIGH
94. ss CHECKED TITLE ENG APPR MFG APPR COMMENTS Alexander Nolet A Shaft Inout 1 SCALE 1 1 WEIGHT SHEET 1 OF 1 0 625 CLEARNACE FOR 6 Z 0 279 X 100 4 QOO CN O OO OO LO CN o C 0 020 1 625 0 020 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE gt IS PROHIBITED NEXT ASSY USED ON APPLICATION 4 UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL TWO PLACE DECIMAL THREE PLACE DECIMAL 005 INTERPRET GEOMETRIC TOLERA Aluminum 6061 FINISH DO NOT SCALE DRAWING PER 3 0 125 Quantity 2 NAME DATE DRAWN CHECKED TITLE ENG APPR MFG APPR Q A COMMENTS SIZE DWG REV A Shaft Seal Cover SCALE 2 1 WEIGHT SHEET 1 OF 1 0 730 6 32 TAPPED THR 4X PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE gt ANY REPRODUCTION IN PART OR AS WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE gt IS PROHIBITED 8 5 NEXT ASSY APPLICATION 7 4 USED ON AQ Go in CO NI OO 317
95. ted Light Ray Offset from Reactor Centerline Reactor Centerline 30 20 10 0 10 20 30 Collector Width All distance normalized to reactor radius Figure 59 Reflector error analysis ano ge MATLAB script for Reflector analysis VISUALIZE System ERROR Points per Sweep Div 15 Num Div 50 zlimit 3 pw 4 rw 2 Device Parameters units in inches Reactor Diameter D 3 Collector Width W 68 Distance from to AoR as of Distance from to Base of Collector AoR 0 Focal Length FL 3 W Angles in degrees and lengths in inches Solar Angle Misalignment sam 2 109 Page Angular Parabola Error ape 0 Offset Parabola Error OPE 0 Convert Inches to reactor radius lengths and angles to radians R 0 2 r 1 w W R fl FL R aor AoR 100 fl ope OPE R sam sam pi 180 ape ape pi 180 lnit Parabola Origin at Axis of Rotation Rsam cos sam sin sam sin sam cos sam fp Rsam 0 aor a 1 4 c fl aor x 5 w w Num 1 5 w 2 c Shape TS Rsam x y TS 1 110 5 2 Calculate Parabola Angle from Global Horizontal ArcLength 0 theta zeros 1 Num TSO zeros 2 Num for n 2 Num 1 if xp n lt 0 theta n pi atan2 yp n 1 yp n 1 xp n 1 xp n 1 else theta n atan2 yp n 1 yp n 1 xp n 1 xp n
96. the predicted cycle time for each batch of biochar is 48 minutes The cycle time could be as short as 34 min or as long as 65 min depending on environmental conditions on any given day The approach used to determine these values is presented in Appendix There are two principle modes of error in a parabolic path offset and angular difference During day to day tracking the collector s difference from the solar azimuth is the principle error To visualize these errors a Matlab script was written included in Appendix H to plot the incident and reflected light as seen in Figure 10 During the derivation of the governing equations it was found that collector misalignment and angular misalignment at a point on the collector are additive The first result was that offset error has no impact The second significant observation was the effect of focal length on the tolerance of angular misalignment The will be observed in greater detail with a quantitative measure Reflected Light With an Angular Misalignment Incident Light 0 Y 2 degree Misalignment 20 15 10 5 0 5 10 15 20 Figure 10 Matlab Analysis showing effects of misalignment The focal length ratio was minimized to take advantage of the higher tolerance to angular tracking misalignment and collector fluctuations in the collector surface As the focal length ratio decreases the curvature of the of the parabola increases As the curvature increases the stiffness t
97. the thin edge of the 0 125 in thick ribs and a fillet of silicone lay on either side of the rib surface interface Reflective surface is Alanod Square tube spacers Aluminum ribs Figure 13 Current reflector design Research determined that the preferred reflective material of past semesters 3M Solar Film had been discontinued Besides its unavailability the solar film has a difficult installation procedure and requires a thick sheet of backing material in order to give the surface structural integrity In order to address these concerns Alanod a high polish anodized aluminum sheet was used as the reflective surface The Alanod is 0 5 mm thick making installation easier than the flexible film and it is available both domestically in the United States as well as through international dealers in Africa Because the Alanod was only available in 24 in x 48 in sheets three pieces would be needed to cover the 48 in x 65 in 32 Page reflector In order to abate misalignment problems where the three sheets meet a piece of 0 032 in thick aluminum sheet the size of the entire reflector was used as a substrate between the ribs and Alanod The same weather resistant tape mentioned above was used to join the Alanod and this aluminum backer In order to provide structural rigidity of the reflector upon removal from the frame as is necessitated during shipping the ribs are spaced apart by pieces of 1 in x 0 072
98. these mechanical electro mechanical areas outside materials no direct test enclosure to resist enclosures water amp dust Design components Parts that can corrode 0 parts In order to be useable for at least 15 design review no direct that are not easily that are not coated years should not corrode test corroded with resistant paint Parts that move and 0 parts are made of corrodible material 77 Page Tracking Drives against wind The panel tracks in wind of 20 mph this is the maximum wind we ve seen in Ghana on days where there is sufficient sun to operate Operate with a fan blowing on the reflector Accurately designed for Ghanaian Latitude Tracks angle of sun at median elevation angle for 7 5 degree s North Or end effects will become non negligible 2596 Design at correct angle no direct test Tracking Accuracy The tracking system shall drive the panel at a speed of 15 1 degrees hour more than 1096 of light will miss if not and no longer function during time periods specified Measure rate of movement of tracking system while in use Long lasting Lasts long enough to Limit areas of wear Minimum component gt 10 years In order to exceed worst payback Design for longevity no pay for itself life period should last at least 10 years direct test Use only long lasting components Use simple of components gt 60 So that
99. theta 1 theta 2 theta Num theta Num 1 plot TS 1 theta Generate Offset Parabola for 1 Num if xp n lt 0 TSO n TS n sin theta n cos theta n ope else TSO n TS n sin theta n cos theta n ope end end 118 Page z zeros 1 Num RRay zeros 2 Num N zeros 2 Num for n 1 Num inc theta n ape RRay n fp 1 TSO 1 n fp 2 TSO 2 n if xp n lt 0 N n sin inc cos inc acos dot RRay n N n mag RRay n mag N n inc else N n sin inc cos inc del acos dot RRay n N n mag RRay n mag N n inc end z n sqrt RRay 1 n 42 RRay 2 n A2 sin del end end 119 Page Appendix Energy Calculations For the purposes of this discussion a standard 1 m reflector will be used This means that the projected reflector area normal to the light source Sun is 1 m E 2025 x 1 kg x Ah 0 25 kg x 2676 E 84 EI 0 64 MJ 1 Furthermore from a chemical balance of the biomass the process requires an input of energy to cause breakdown of hemicellulose which for the biomass used here is on the order of 1 77 MJ kg making the energy input required for chemical transformation of the sample E 1 kg x 1 77 E 1 77 2 Summed together the total energy needed to drive off the water produced and chemical transformation in the 1 kg sample is E 0 64 MJ 1 77
100. though the team achieved favorable throughput having the glass on more tests with different variables listed below should have been conducted Having this data would give us an idea on how the project would perform should the glass break or become damaged in the field e Time of day The sun is stronger at different times of the day We were only able to test in the afternoon and not in the early morning The project is expected to be used from sunrise to sun set in the field so testing should have been done to meet its use 72 Page Biomass Moisture Content Multiple samples should have been used at various levels of dryness to determine how important biomass moisture and cooking time char quality is Also if possible the corn cobs should be dried outside in the sunlight to replicate what Ghanaian farmers would do For this testing the team used 3 batches of corn that were dried in different ovens for different times Theprocess for drying the biomass for testing purposes varied On average the cobs were place in a conventional oven for about 10 hours at 250 degrees Fahrenheit Particle Size More testing should have been done to determine if the size of the biomass particles has a strong correlation to pyrolysis time char quality The team tested whole cobs without the glass attached twice and another two tests using cut up pieces of various sizes pictured below The second set of testing also had the glass on the reactor tube Ideal
101. tial threats from global climate change by sequestering carbon in trees If all of the biochar produced replaces the cutting down of trees by conservative estimates some 80X more carbon will be sequestered than used in manufacturing of the solar torrefaction unit However the solar torrefaction unit requires different metals which could be from questionable sources The necessary analysis to determine this was of concern to the team but was beyond the scope of this report 4 3 Sustainability The system does add a component of sustainability by reducing the dependence of farmers on distant charcoal supplies However it is not clear whether the current manufacturing and shipping processes to create and deploy the unit are sustainable While the team was largely concerned with sending a working prototype to Ghana it is hoped that any future teams and the work of Professor Eglash and his students over the summer of 2012 will take this into account 4 4 Manufacturability The present system is complex requiring a large number of components many of which must be custom made for this design This means that to deploy the system in mass would require a large and 26 Page complex manufacturing operation for the individual components and that assembly of the system would take a significant amount of time As a result much of the work by Professor Eglash s student workers in the Summer of 2012 will focus on finding a sustainable and affordable way
102. time of the system Low cost and lifetime means that the system must be as inexpensive as possible while meeting the previously discussed specifications Unfortunately the limited time for the testing cycle limits the rigor in showing the lifetime of the system A consciousness design will have to suffice in this case The priority for testing is the verification that the system performs its main objective There are four critical requirements with regard to tracking accuracy and precision 1 The tracking system shall drive the panel at a nominal speed of 15 degrees hour 2 The tracking system speed shall not differ from the nominal speed by more than 1 degrees hour from the speed at the start of that hour 3 Maximum periodic variation in Collector and Solar angles during tracking is 1 degree 4 Thecollector angle feedback and adjustment shall be designed so that the user can be reasonably expected to set the collector to within 1 degree of accuracy 5 1 3 Preliminary Design The chosen reflector design is a trough because of the reduced cost and moderate levels of efficiency as appropriate for the customer needs This decision is a confirmation of the work of previous groups in deciding an appropriate shape through rigorous methods including decision matrices However the exact geometry had yet to be defined Matlab was used to optimize the reflector shape to reduce cost while keeping an acceptable level of error and reasonable height
103. to take all of someone s time and thus should require no more time operate than 1 hour day in optimum conditions It should also not require a complex manual to operate and thus the number of steps to use the system should be limited to 5 during use and 3 to set up To achieve this all of the components were chosen to be as light weight as feasible fit together in a simple way crate packing was considered extensively and use was considered at every point in the design process 1 3 Justification for the Project The goals for the biomass processor are to reduce deforestation in Northern Ghana to reduce the amount of wasted biomass from agricultural products on Southern Ghanaian farms and the alleviation of poverty in Ghana These problems are discussed in more depth in Section 1 1 1 4 Project History In order to understand where the team is going it is important to look at the context of previous work In particular this semester spring 2012 aims to build on the work of 5 other steams starting in the semester of fall 2010 spanning until fall 2011 The basic objectives outcomes and components used this semester are outlined in Table 2 However of particular note is that much of the information on the user and feasibility for every component of this project has been shown by past teams Moreover past teams have made clear the potential usefulness of this system Table 2 Project history summary table Team Semester Goals W
104. uses solar energy to process agricultural waste to produce biochar an effective replacement for charcoal thus reducing deforestation lowering energy costs and allowing for small scale decentralized char production The process of biochar production requires Dehydrating biomass and heating it to 300 C for 45min During torrefaction sample of biomass usually loses 2596 of its mass usually through evaporation of water produced during hemicellulose depolymerization Prins 2005 3 2 Dehydrating Biomass Dehydrating agricultural waste is an important first step to torrefaction because it accelerates the process by reducing the energy for vaporization of moisture and reduces the amount of gassing released gases Dehydration is a common practice and while there are industrial systems for dehydration there are some very low tech solutions as well In particular the Fall 2011 Design Lab group designed a solar dehydrator however simply leaving the biowaste out in the sun on a dry day can have a similar effect and requires no additional hardware Top Trimetric View Black surface denotes collector sheet Figure 6 Possible solar dehydrator design deemed unnecessary 18 Page 3 3 Charcoal Stoves In recent years there have been great improvements to charcoal stoves The Toyola stove Wahab 2011 15 high efficiency low smoke emitting device The stove consists of an hourglass design with holes in the middle which uses
105. vection reactor inner surface insert outer surface q_23_cond conduction reactor outer surface inner absorber pipe surface q_3_SolAbs solar irradiation absorption incident solar irradiation outer absorber pipe surface q_34_conv convection reactor outer surface inner glass envelope surface q_34_rad radiation reactor outer surface inner glass envelope surface q_45_cond conduction glass envelope inner surface outer glass envelope surface q_5_SolAbs solar irradiation absorption incident solar irradiation outer glass envelope surface q_56__conv convection glass envelope outer surface surrounding air q_57_rad radiation glass envelope outer surface sky q_36_conv convection reactor outer surface surrounding air iati u u 37 radiation reactor outer surface sk 104 Page 1 D EES Thermal Analysis Script INPUTS Material constants etc k_Reactor 400 W m K Copper 400 Steel 17 k_Glass 1 2 W m k h_1_Air 15 W m 2 K 56 Air 25 W m 2 K epsilon 320 97 Reactor surface emissivity epsilon 420 05 Inner Glass envelope emissivity epsilon 520 05 Outer Glass envelope emissivity sigma 5 67E 8 IW m 2 K 4 Dimensions m D 0 0 063373 Inner Insert Diameter 0 1 0 066675 Outer Insert Diameter D 2 0 074803 Inner Reactor Diameter D 3 0 0762 Outer Reactor Diameter D 4 0 107 Inner Glass Diameter D 5 0 110 Outer Glass Diameter Temperatures C T 7 T 6 8 Sky 6 296 15 Ambient T 5
106. w the results of the Thermal Finite Element Analysis performed on the reactor Note that this is a steady state simulation At Steady State the reactor reaches 280 C which is the ideal temperature for torrefaction Edward S Lipinsky 2002 This calculation however assumes a rather conservative incident solar irradiation 85 of average solar radiation For an overview of the assumed 37 Page heat fluxes used in this model along with a map of the thermal resistances see Appendix C Moreover additional thermal analysis was performed using an EES Engineering Equation Solver Script see Appendix C Both analyses yield very similar results setting the core temperature at about 280 C Temp Celsius Figure 18 Thermal FEA Results sectioned view Figure 19 Thermal FEA Results full assembly 38 Page Figure 20 Thermal FEA Results insert only 5 2 4 Preliminary Design The new design consists of a thin walled 0 060 in copper pipe Absorber coated with a high absorbance coating emissivity 97 AET Solar 2011 for increased solar radiation absorption This special coating covers two requirements at once it ensures that a maximum of the incoming solar energy is absorbed and subsequently only small amount is lost to the annulus air A tubular glass envelope Figure 14 Figure 17 encases the entire reactor assembly in order to reduce convective losses from the aforementioned copper reactor It rests on n
107. with hot components required to touch a surface capable of burning 79 Page Appendix B Test Plans Test Procedure for preprocessing the corn cobs Wet corn cob Remove as many kernels as possible Temperature F uu n Measure wet Humidity weight my 94 Dry corn cob Measure dry weight Wa Kk Drying time hours cy Testing procedure for temperature measurement in actual system Objectives Moisture Evaluation Calculate moisture content Repeat for various scenarios measure the precise temperature change vs time during the torrefaction process by the actual built system To determine the ideal cook time of biomass to reach the desired characteristic of torrified char the throughput produced at different parts of the day Materials 2Thermocouples 2thermocouple modules 1 multimeter 2 reference temperature thermostat data acquisition board Short Wires 80 Page Laptop with LabVIEW DAQ installed Biomass apparatus including cooper insert and steel hooks Zip Lock bags labeled A B C D respectively Sharpie or pen Funnel Bowl Rag Brush Tape Part A thermocouple amp data acquisition setup 1 2 9 Obtain 4 thermocouples along with modules data acquisition multi meter Calibrate the modules as i
108. y 2 B eacior 2 DO NOT SCALE DRAWING SCALE 1 2 WEIGHT 0 63 Ib SHEET 1 OF 1 3 2 Note This schematic is for use as a water jet cutting reference only Do not use to machine other features 90 24 13 3 00 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF lt INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION NEXT ASSY USED ON 5 4 U D NLESS OTHERWISE SPECIFIED IMENSIONS ARE IN INCHES TOLERANCES FRACTIONAL NGULAR MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL TERPRET GEOMETRIC TOLERANCING PER M ATERIA Mild Steel FI ISH Mill DO NOT SCALE DRAWING 3 NAME DATE Design Lab Biomass DRAWN CHECKED TITLE ENG Reactor WI Q A COMMENTS SIZE DWG NO REV Reactor Endcap WJ Quantity 2 A T 2 SCALE 1 1 WEIGHT SHEET 1 OF 1 2 1 3 500in 88 90mm DRILL THRU 0 13in 3 l8mm 5 00 127mm SECTION A A UNLESS OTHERWISE SPECIFIED NAME DATE D b DIMENSIONS ARE IN INCHES DRAWN HBW 2 29 2012 eSIQ n a lOMASS TOLERANCES FRACTIONAL CHECKED TITLE ANGULAR MACH 0 5 NEAR Upper Flange INTERPRET GEOMETRIC Q A TOLERANCING PER CO
109. ywood FINISH Router Laser DO NOT SCALE DRAWING 3 UNLESS OTHERWISE SPECIFIED NAME DATE DRAWN CHECKED ENG APPR MFG APPR QA COMMENTS Quantity 5 Design Lab Biomass TITLE Glue Rib SIZE DWG REV B Glue Rib SCALE 1 16 WEIGHT SHEET 1 OF 1 26 4129 5x 0 386 005 62 43 PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF lt INSERT COMPANY NAME HERE REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON INSERT COMPANY NAME HERE IS PROHIBITED APPLICATION 5 4 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN TOLERANCES CHECKED THREE PLACE DECIMAL 20 005 ENG APPR MFG APPR INTERPRET GEOMETRIC QA TOLERANCING PER COMMENTS MATERIAL 1 8 6061 FINISH Quantity 7 As Mochineq Y DO NOT SCALE DRAWING 3 2 Design Lab Biomass TITLE Inner Rib SIZE DWG NO REV SCALE 1 16 WEIGHT SHEET 1 OF 1 52 25 DETAIL SCALE 1 2 500 da B 2X 257 THRU DETAIL B SCALE 1 2 UNLESS OTHERWISE SPECIFIED NAME DATE DIMENSIONS ARE IN INCHES DRAWN HBW 3 21 2012 Design Lab 7 Biomass TOLERANCES ANGULAR 0 5 CHECKED TITLE TWO PLACE DECIMAL 0 050 THREE PLACE DECIMAL 0 005 ENG APPR TOLERANCING COMMEN

Biomass Final_Report 2012

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