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Title: Spectral splitting optimization for high-efficiency solar photovoltaic and thermal power generation

Utilizing the full solar spectrum is desirable to enhance the conversion efficiency of a solar power generator. In practice, this can be achieved through spectral splitting between multiple converters in parallel. However, it is unclear which wavelength bands should be directed to each converter in order to maximize the efficiency. We developed a model of an ideal hybrid solar converter which utilizes both a single-junction photovoltaic cell and a thermal engine. We determined the limiting efficiencies of this hybrid strategy and the corresponding optimum spectral bandwidth directed to the photovoltaic cell. This optimum width is inversely proportional to the thermal engine efficiency and scales with the bandgap of the photovoltaic cell. This bandwidth was also obtained analytically through an entropy minimization scheme and matches well with our model. We show that the maximum efficiency of the system occurs when it minimizes the spectral entropy generation. This concept can be extended to capture generalized non-idealities to increase the usefulness of this technique for a range of full solar spectrum utilization technologies.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Grant/Contract Number:
FG02-09ER46577; SC0001299; #DE-FG02-09ER46577
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 109; Journal Issue: 24; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; Band Gap; Equilibrium Thermodynamics; Photovoltaics; Blackbody; Solar Cells; Statistical Thermodynamics
OSTI Identifier:
1473861
Alternate Identifier(s):
OSTI ID: 1336498

Bierman, David M., Lenert, Andrej, and Wang, Evelyn N.. Spectral splitting optimization for high-efficiency solar photovoltaic and thermal power generation. United States: N. p., Web. doi:10.1063/1.4971309.
Bierman, David M., Lenert, Andrej, & Wang, Evelyn N.. Spectral splitting optimization for high-efficiency solar photovoltaic and thermal power generation. United States. doi:10.1063/1.4971309.
Bierman, David M., Lenert, Andrej, and Wang, Evelyn N.. 2016. "Spectral splitting optimization for high-efficiency solar photovoltaic and thermal power generation". United States. doi:10.1063/1.4971309. https://www.osti.gov/servlets/purl/1473861.
@article{osti_1473861,
title = {Spectral splitting optimization for high-efficiency solar photovoltaic and thermal power generation},
author = {Bierman, David M. and Lenert, Andrej and Wang, Evelyn N.},
abstractNote = {Utilizing the full solar spectrum is desirable to enhance the conversion efficiency of a solar power generator. In practice, this can be achieved through spectral splitting between multiple converters in parallel. However, it is unclear which wavelength bands should be directed to each converter in order to maximize the efficiency. We developed a model of an ideal hybrid solar converter which utilizes both a single-junction photovoltaic cell and a thermal engine. We determined the limiting efficiencies of this hybrid strategy and the corresponding optimum spectral bandwidth directed to the photovoltaic cell. This optimum width is inversely proportional to the thermal engine efficiency and scales with the bandgap of the photovoltaic cell. This bandwidth was also obtained analytically through an entropy minimization scheme and matches well with our model. We show that the maximum efficiency of the system occurs when it minimizes the spectral entropy generation. This concept can be extended to capture generalized non-idealities to increase the usefulness of this technique for a range of full solar spectrum utilization technologies.},
doi = {10.1063/1.4971309},
journal = {Applied Physics Letters},
number = 24,
volume = 109,
place = {United States},
year = {2016},
month = {12}
}

Works referenced in this record:

Detailed Balance Limit of Efficiency of p‐n Junction Solar Cells
journal, March 1961
  • Shockley, William; Queisser, Hans J.
  • Journal of Applied Physics, Vol. 32, Issue 3, p. 510-519
  • DOI: 10.1063/1.1736034