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25 pvpmc workshop(u iowa)

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8th PVPMC Workshop, May 9-10 2017

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25 pvpmc workshop(u iowa)

  1. 1. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Ray Tracing Models for Bifacial PV Performance Amir Asgharzadeh Shishavan, Fatima Toor Electrical and Computer Engineering Department University of Iowa May 10, 2017
  2. 2. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Agenda  Analysis of the impact of installation parameters and system size on bifacial gain and energy yield of PV systems  RADIANCE PV modeling  Combined effect of tilt angle, height, and albedo  Effect of the system size  Simulation of Sandia’s Fixed-Tilt String-Level Arrays  Results and analysis  Conclusions and next steps 2
  3. 3. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop RADIANCE PV Modeling  We modeled the PV systems using RADIANCE, which is a simulation software to compute the radiance profile of physical systems by ray-tracing methods  This study approximates the Perez direct and diffuse model [1]  In our model, we utilized the dimensions and electrical characteristics of Prism Solar’s Bi60-368BSTC bifacial module (front and backside efficiencies of 17.4% and 15.6%, respectively, which is equivalent to a bifaciality of ~90%)  TMY3 weather (hourly) data for Albuquerque, NM was used to acquire global horizontal irradiance (GHI), diffuse horizontal irradiance (DHI) and direct normal irradiance (DNI)  Azimuth and zenith angles (also hourly data) were derived from PV_LIB Toolbox 3 [1] R. Perez, R. Seals, and J. Michalsky, "All-weather model for sky luminance distribution - preliminary configuration and validation," Solar Energy, vol. 50, pp. 235-245, Mar 1993.
  4. 4. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop RADIANCE PV Modeling Single moduleA row consisting of five modules Five rows, each with five modules 4  Three south-facing PV system configurations were considered
  5. 5. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop RADIANCE PV Modeling  Installation parameters  h: Height (0.1m to 3m)  θ: Tilt angle (10º to 90º)  α: Albedo (21% , 43% , 81%)  We ran hourly simulations sweeping parameters mentioned above around three important dates of the year: summer solstice, winter solstice and fall equinox θ h α 5
  6. 6. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Agenda  Analysis of the impact of installation parameters and system size on bifacial gain and energy yield of PV systems  RADIANCE PV modeling  Combined effect of tilt angle, height, and albedo  Effect of the system size  Simulation of Sandia’s Fixed-Tilt String-Level Arrays  Results and analysis  Conclusions and next steps 6
  7. 7. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Combined Effect of Tilt angle, Height and Albedo – Energy yield 7 Summer Solstice
  8. 8. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Combined Effect of Tilt angle, Height and Albedo – Energy yield 8 Fall Equinox
  9. 9. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Combined Effect of Tilt angle, Height and Albedo – Energy yield 9 Winter Solstice
  10. 10. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Combined Effect of Tilt angle, Height and Albedo – Bifacial Gain 10 Summer Solstice 𝐵𝐺𝐸 ≡ 𝐸 𝑏 𝐸 𝑚 − 1 (𝐸 𝑏 and 𝐸 𝑚 are energy yield for bifacial and monofacial cases respectively)
  11. 11. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Combined Effect of Tilt angle, Height and Albedo – Bifacial Gain 11 Fall Equinox 𝐵𝐺𝐸 ≡ 𝐸 𝑏 𝐸 𝑚 − 1 (𝐸 𝑏 and 𝐸 𝑚 are energy yield for bifacial and monofacial cases respectively)
  12. 12. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Combined Effect of Tilt angle, Height and Albedo – Bifacial Gain 12 Winter Solstice 𝐵𝐺𝐸 ≡ 𝐸 𝑏 𝐸 𝑚 − 1 (𝐸 𝑏 and 𝐸 𝑚 are energy yield for bifacial and monofacial cases respectively)
  13. 13. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Agenda  Analysis of the impact of installation parameters and system size on bifacial gain and energy yield of PV systems  RADIANCE PV modeling  Combined effect of tilt angle, height, and albedo  Effect of the system size  Simulation of Sandia’s Fixed-Tilt String-Level Arrays  Results and analysis  Conclusions and next steps 13
  14. 14. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop RADIANCE PV Modeling Single moduleA row consisting of five modules Five rows, each with five modules 14  Three south-facing PV system configurations were considered
  15. 15. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Effect of the System Size  Energy yield with optimum tilt angle, height of 1.5 m and albedo of 21%  Increase in the system size results in decrease in the performance  Middle module in multi-row bifacial array generates about 7% less energy comparing with single module on summer solstice, 6 % on fall equinox and 5 % on winter solstice. 15
  16. 16. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Agenda  Analysis of the impact of installation parameters and system size on bifacial gain and energy yield of PV systems  RADIANCE PV modeling  Combined effect of tilt angle, height, and albedo  Effect of the system size  Simulation of Sandia’s Fixed-Tilt String-Level Arrays  Results and analysis  Conclusions and next steps 16
  17. 17. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Sandia’s Fixed-Tilt String-Level Arrays  Four rows at 15˚, 25˚, 35˚, and 45˚ tilt  Each row has two strings of 8 modules (one monofacial and one bifacial)  Two types of bifacial modules are used :  Prism Solar  Sunpreme 17
  18. 18. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop RADIANCE Simulation  Each row has 2 reference cells (top and bottom) for backside and one reference cell for front side  We simulated both front side and backside irradiance using RADIANCE modeling  Simulated data was compared to field measurements for a partially cloudy day (September 25, 2016) 18 Top reference cell Bottom reference cell
  19. 19. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Simulated Scene with RADIANCE S15 S25 S35 S45 19
  20. 20. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Simulated Scene with RADIANCE -top view 244 cm 191 cm 305 cm S15 S25 S35 S45 20
  21. 21. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop RMSD and NRMSD  Calculated RMSD (Root mean square deviation) and Normalized RMSD (NRMSD) for backside simulations to compare the simulated data with measured data NRMSD = 𝑅𝑀𝑆𝐷 𝑥1,𝑚𝑎𝑥 − 𝑥1,𝑚𝑖𝑛 𝑥1 ∶ 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑖𝑟𝑟𝑎𝑑𝑖𝑎𝑛𝑐𝑒 𝑥2 ∶ 𝑠𝑖𝑚𝑢𝑙𝑎𝑡𝑒𝑑 𝑖𝑟𝑟𝑎𝑑𝑖𝑎𝑛𝑐𝑒 n : number of data 21
  22. 22. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Front side Irradiance Measured Ref. cell simulation  Simulated and measured data match very well (NRMSD~2.5%, RMSD~25 𝑊/𝑚2) 22
  23. 23. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop First row (Tilt = 15˚) – Backside  Simulation data has NRMSD value of 4.6% and 11.6% for top and bottom ref. cells respectively  The highest non-uniformity among the rows 23 Measured-top Ref. cell simulation Measured-bottom
  24. 24. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Second row (Tilt=25˚) - Backside  Simulation data has NRMSD value of 4.4% and 5.2% for top and bottom ref. cells respectively  RMSD (NRMSD) values for the second row is lower than for the first row, which shows it has better match with the measured data 24 Measured-top Ref. cell simulation Measured-bottom
  25. 25. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Third row (Tilt=35˚) - Backside  Simulation data has NRMSD value of 5.6% and 4.8% for top and bottom ref. cells respectively 25 Measured-top Ref. cell simulation Measured-bottom
  26. 26. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Fourth row (Tilt=45˚) - Backside  Simulation data has NRMSD value of 4.2% and 7.8% for top and bottom ref. cells respectively  The least non-uniformity among the rows 26 Measured-top Ref. cell simulation Measured-bottom
  27. 27. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Agenda  Analysis of the impact of installation parameters and system size on bifacial gain and energy yield of PV systems  RADIANCE PV modeling  Combined effect of tilt angle, height, and albedo  Effect of the system size  Simulation of Sandia’s Fixed-Tilt String-Level Arrays  Results and analysis  Conclusions and next steps 27
  28. 28. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop Conclusions and Next Steps  Installation parameters (tilt angle, height and albedo) impact the energy yield and bifacial gain of bifacial PV systems in a complex manner  System size impacts the performance of the system (Energy yield of a large array with ground albedo of 21% can decrease up to 7% comparing to a single module)  Simulation of Sandia’s fixed-tilt string-level arrays shows a good match between the simulated data and field measurements  The next steps for the project include compare simulation and measurement data for different sky and weather conditions and consider the impact of shading on bifacial gain as a function of the time of the day 28
  29. 29. May 15, 2017 8th PV Performance Modeling and Monitoring Workshop 29 Thanks for your attention Any Questions?

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