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

Journal Article · Fri Dec 16 00:00:00 EST 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4971309· OSTI ID:1473861

Bierman, David M.  ^[1]; Lenert, Andrej  ^[2]; Wang, Evelyn N. ^[1]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States)

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.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: FG02-09ER46577; SC0001299; #DE-FG02-09ER46577
• OSTI ID: 1473861
• Alternate ID(s): OSTI ID: 1336498
• Journal Information: Applied Physics Letters, Vol. 109, Issue 24; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
Band Gap
Equilibrium Thermodynamics
Photovoltaics
Blackbody
Solar Cells
Statistical Thermodynamics