Solar thermophotovoltaic efficiency potentials : surpassing photovoltaic device efficiencies

Abstract

Solar energy has gained more attention in recent years due to increased concerns about the continued use of fossil fuels. Solar energy is a form of renewable energy, and solar energy technology does not release greenhouse gases responsible for climate change. While photovoltaic (PV) cells, which convert sunlight into electrical energy, are becoming more widely used, they are limited in their ability to convert sunlight into electricity. One of the limitations of PV energy generation is caused by the fact that only a limited portion of the energy spectrum of sunlight contributes to electricity generation. Solar thermophotovoltaics (TPV) aim to improve the efficiency with which sunlight can be converted to electrical energy by converting solar energy to thermal energy first before generating electrical energy with a PV cell. Instead of direct illumination by sunlight, the sunlight is absorbed by an intermediate material and then reemitted as a means of energy spectrum control, which in theory allows for more photons to generate useful electrical energy. The efficiency of solar TPV systems have been modeled. These models demonstrate that solar TPV devices have a higher potential efficiency than PV device counterparts. Yet, solar TPV devices are not yet suitable for any sustainable use, and there are many engineering challenges that need to be overcome in order to cross over from theory into practical use.