Review of Lecture 9 T I M , n o e t h l • Solar hot water systems C a g m r n • Maximum solar concentration e a h n G T o / i • Methods for©concentration r s t ola er h v g tand • Nontracking tracking i S n r o y c p C e • Solar thermal-mechanical o r i y C g D r energy conversion 7 97 ne 9 9 9 E • EM wave . . l 2 r 2 ca calculation of surface properties i o r F ct e l E Review of Lecture 10 By C. Schuh T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 3.31 in Porter, David A., and Kenneth E. Easterling. Phase Transformations in Metals and Alloys. 2nd ed. New York, NY: Chapman & Hall, 1992. Review of Lecture 11 By I. Celanovic T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Courtesy of Ivan Celanovic. Used with permission. Lecture 12 Solid-State Solar-Thermal Energy Conversion MIT , n e to h l C a g m r n • Solar thermophovoltaics e a h G /T ion © lar rs • Solar thermophotonics t e h o v g i S n r • Solar thermoelectrics t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Shockley-Queisser Limit of Solar Cells (Lec.7) T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 3 in Henry, C. H. "Limiting Efficiencies of Ideal Single and Multiple Energy Gap Terrestrial Solar Cells." Journal of Applied Physics 51 (August 1980): 4494-4500. Shockley, W. and Queisser, H.J., Journal of Applied Physics, 32, 510 (1961). Henry, C.H., Journal of Applied Physics, 51, 4494 (1980). Where is energy lost? T I M For E =1 eV , n ENERGY e • Energy below theto gap: 20% h l energy • Average photon C a g gap:rm1.9 eV above n e Excess •aChemical potential: 0.7 eV h n G Energy T o / i 1eV 0.7eV r © s η = 0.8 ×r × = 0.3 a t l e h 1.9eV 1eV o E v g i S n r k t o y hν c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E g g Terrestrial Solar Spectrum (W/m2μm) 1800 1600 AM1.5 Solar Spectrum Energy Usable for Silicon PV Cells 1400 1200 1000 800 Bandgap of Silicon (1.1 μm) 600 400 200 0 0 0.5 1 1.5 2 Wavelength (μm) 2.5 3 Solar 1500 1000 500 0 0 0.5 1.0 1.5 2.0 2.5 3.0 Power (W/m2μm) (a) 1.5E4 1.0E4 0.5E4 0 0 2 4 6 (d) 8 10 12 Emissivity Absorptance Power (W/m2μm) Solar Thermophotovoltaics T I M , n o e t h l C Insolation a g rm n Optical Concentrator e a h G /T ion © lar rs Selective Wavelength (μm) t e h o v g i Absorber S n r t o Emitter y Irradiance c p C e From Emitter ir o y C D rTPV g Selective Cell 7 97 ne 9 9 9 E Wavelength (μm) . . l 2 r 2 ca Thermal Management i Wavelength (μm) o r F ct e l E 1.5 Absorber 1.0 0.5 (b) 0 0 1.5 5 10 (c) 15 Emitter 1.0 0.5 0 0 2 4 6 8 10 12 Blackbody At Sun’s Temperature Ts Maximum Efficiency T(Lec.8) I of a Solar Thermal Engine M , n e to Heat Transferred tohAbsorber l C a g rm Blackbody n Q = σ (T h−eT ) a Absorber at T G /T ion © lar rs J t Thermal Efficiencye h o g t S nv i r W y ec Cσo(T − T ) T p Engine o C Dir rgηy = σT = 1 − T 7 97 ne 9 J 9 9 E . . l 2 r 2 ca Carnot Efficiency i r TFo t c Ta e l η = 1− E T h 4 4 4 4 s h 4 s th c a 4 s 4 s Maximum Efficiency T I of a Solar Thermal Engine (Lec.8) M , n e to h l C a ⎛ T ⎞⎛ T ⎞ g m r n η = η η = ⎜⎜1 − ⎟⎟⎜ 1− ⎟ e a h T T n ⎠ G ⎠⎝ ⎝ T o / i r © s t ola er h g t S nv i r y ec Co p o C Dir rgy Maximum:7 85% @ T=2450K 7 ne 9 9 For T.9 =300 K .9 E l 2 r 2 ca i o r F ct Temperature (K) e El 4 0.9 a 4 s 0.8 0.7 Efficiency th C 0.6 0.5 0.4 0.3 Series8 0.2 0.1 a 0 0 1000 2000 3000 4000 5000 6000 Problems T I M , n o e t h l • Needs very narrow bandwidth to C a g m r n achieve Carnot efficiency solar cells. e a h n G T o / i • Solar absorption and radiation from r © s t ola er h v at 2450 K. absorber rdoes balance g tnot i S n y ec Co p • Difficult to operate at 2450 K. o r i y C D rg 7 selective 7 nesurfaces do not exist. • Ideal 9 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Wuerfel and Ruppel Analysis – Black Absorber IT M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Images removed due to copyright restrictions. Please see Fig. 1, 3, 4 in Würfel, Peter, and Wolfgang Ruppel. "Upper Limit of Thermophotovoltaic Solar-Energy Conversion." IEEE Transactions on Electron Devices ED-27 (April 1980): 745-750. Wuerfel and Ruppel, IEEE Trans. Elec. Devices, ED-27, 745, 1980 Wuerfel and Ruppel Analysis – Selective Absorber IT M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Images removed due to copyright restrictions. Please see Fig. 6 and 7 in Würfel, Peter, and Wolfgang Ruppel. "Upper Limit of Thermophotovoltaic Solar-Energy Conversion." IEEE Transactions on Electron Devices ED-27 (April 1980): 745-750. Wuerfel and Ruppel, IEEE Trans. Elec. Devices, ED-27, 745, 1980 Wuerfel and Ruppel Analysis – Selective Absorber + Filter IT M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rgy 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Images removed due to copyright restrictions. Please see Fig. 9-11 in Würfel, Peter, and Wolfgang Ruppel. "Upper Limit of Thermophotovoltaic Solar-Energy Conversion." IEEE Transactions on Electron Devices ED-27 (April 1980): 745-750. Wuerfel and Ruppel, IEEE Trans. Elec. Devices, ED-27, 745, 1980 Optimal Bandgap & Temperature IT M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 5 in Tobias, I., and A. Luque. "Ideal Efficiency and Potential of Solar Thermophotonic Converters Under Optically and Thermally Concentrated Power Flux." IEEE Transactions on Electron Devices 49 (November 2002): 2024-2030. Tobias and Luque, IEEE Trans. Electron Dev. 49, 2024 (2002) Andreev et al., T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 97 97 ne 9 9 E . . l 2 r 2 ca i o r F ct e l E Courtesy of Viacheslav Andreev. Used with permission. Some Examples T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca GaSb Cell i o r F ct e pvlab.ioffe.ru/technology/tpv.html l E Courtesy of Viacheslav Andreev. Used with permission. Solar Thermophotonics T I M , n o e t h l C a g rm n e a h G /T n r o © i a t s l r h o e g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 1 in Tobias, I., and A. Luque. "Ideal Efficiency and Potential of Solar Thermophotonic Converters Under Optically and Thermally Concentrated Power Flux." IEEE Transactions on Electron Devices 49 (November 2002): 2024-2030. Tobias and Luque, IEEE Trans. Electron Dev. 49, 2024 (2002) TPH---Monochromatic Limit T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct T = 1 − e T El cell LED STPH---No Filter T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 3 in Tobias, I., and A. Luque. "Ideal Efficiency and Potential of Solar Thermophotonic Converters Under Optically and Thermally Concentrated Power Flux." IEEE Transactions on Electron Devices 49 (November 2002): 2024-2030. STPH---With Filter T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 4 in Tobias, I., and A. Luque. "Ideal Efficiency and Potential of Solar Thermophotonic Converters Under Optically and Thermally Concentrated Power Flux." IEEE Transactions on Electron Devices 49 (November 2002): 2024-2030. Solar Thermoelectrics IT M , n o e t h • US Patent No. 389124: l C a E. g Weston in 1888 m r n e • aM. Telkes, 765, 1954 h n G /T iJAP, o r © s a r t l e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct Efficiency: 0.63% e El Image removed due to copyright restrictions. Please see Fig. 6 in Telkes, Maria. "Solar Thermoelectric Generators." Journal of Applied Physics 25 (June 1954): 765-777. Solar Thermoelectrics – Flat Panel Prototypes T I M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 6 in Telkes, Maria. "Solar Thermoelectric Generators." Journal of Applied Physics 25 (June 1954): 765-777. Solar Thermoelectric Generator ---Concentrated PrototypesMIT , n e to h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Images and text removed due to copyright restrictions. Please see Fig. 3, 10 and Table III in Dent, C. L., and M. H. Cobble. "A Solar Thermoelectric Generator Experiment and Analysis." Proceedings of the International Conference on Thermoelectric Energy Conversion 4 (1982): 75-78. Hybrid PV and TE T I Solid-State Solar-Thermal Energy Conversion Center M (S TEC Center) , n o e t Gang Chen (Director) http://s3tec.mit.edu/h l a Kraemer et al. C g APL, Junen2008 rm e a h G /T ion © lar rs t e h o v g i S n r t o y c p C solar spectrum partition device e o r C D i rg y 7 97 ne 9 9 9 E . . l 2 r 2 ca 41 % i o r F ct e l E 3 Courtesy of DOE/NREL, Credit - Beck Energy. Courtesy of NASA. Two Configurations IT M , n o e t h l C a g rm n e a h G /T ion © lar rs t e h o v g i S n r t o y c p C e o r i y C g D r 7 7 ne 9 9 9 9 E . . l 2 r 2 ca i o r F ct e l E Image removed due to copyright restrictions. Please see Fig. 1 in Vorobiev, Y. V., et al. "Analysis of Potential Conversion Efficiency of a Solar Hybrid System with a High-Temperature Stage." Journal of Solar Energy Engineering 128 (May 2006): 258-260. Vorobiev et al., J. Solar Energy Eng., 128, 258, 2006. MIT OpenCourseWare http://ocw.mit.edu 2.997 Direct Solar/Thermal to Electrical Energy Conversion Technologies Fall 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.