Thermophotovoltaics: a potential pathway to high efficiency concentrated solar power

A high temperature thermophotovoltaic (TPV) system is modeled and its system level performance is assessed in the context of concentrated solar power (CSP) with thermal energy storage (TES). The model includes the treatment of the emitter and the heat transfer fluid that draws thermal energy from the TES, which then allows for the identification and prioritization of the most important TPV cell/module level properties that should be optimized to achieve maximum performance. The upper limiting efficiency for an idealized system is then calculated, which shows that TPV with TES may one day have the potential to become competitive with combined cycle turbines, but could also offer other advantages that would give CSP an advantage over fossil based alternatives. The system concept is enabled by the usage of liquid metal as a high temperature heat transfer and TES fluid. The system concept combines the great economic advantages of TES with the potential for low cost and high performance derived from TPV cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling.