Solar Thermoradiative-Photovoltaic Energy Conversion

• Published in: Cell reports physical science Vol. 1; no. 12; p. 100258
• Main Authors: Tervo, Eric J., Callahan, William A., Toberer, Eric S., Steiner, Myles A., Ferguson, Andrew J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 23.12.2020; Elsevier
• Subjects: OTHER INSTRUMENTATION; photovoltaic; SOLAR ENERGY; thermal storage; thermophotovoltaic; thermoradiative; thermal storage; solar energy; thermoradiative; thermophotovoltaic
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2020.100258

A continuous supply of renewable energy requires intermittent sources to be paired with storage. Thermal storage is an excellent match for solar energy, but concentrating solar power plants must use high optical concentrations and large plants to be cost competitive. Here, we propose an alternative, solid-state heat engine for solar-thermal conversion consisting of a solar absorber, a thermoradiative cell, and a photovoltaic cell. Heat from the solar absorber or thermal storage drives radiative recombination current in the thermoradiative cell, and its emitted light is used by the photovoltaic cell. Based on the principle of detailed balance, we calculate a limiting solar conversion efficiency of 85% for fully concentrated sunlight and 45% for one sun with an absorber and single-junction cells of equal areas. Solar thermoradiative-photovoltaic systems outperform similar solar thermophotovoltaic converters for low band gaps and practical absorber temperatures, and for a realistic device, this improvement can be up to 7.9% (absolute). [Display omitted] A solar thermal converter that uses thermoradiative and photovoltaic cellsUltimate efficiency limit is 85%, and ideal single-junction one-sun limit is 45%Low band-gap systems perform well at low optical concentrationsSystem with losses can outperform comparable solar thermophotovoltaics by ∼8% Tervo et al. propose a solid-state heat engine for solar-thermal conversion: a solar thermoradiative-photovoltaic system. The thermoradiative cell is heated and generates electricity as it emits light to the photovoltaic cell. Combining these two devices enables efficient operation at low temperatures, with low band-gap materials, and at low optical concentrations.