Greater than 20% radiant heat conversion efficiency of a thermophotovoltaic radiator/module system using reflective spectral control

An InGaAs monolithic interconnected module (MIM) using reflective spectral control has been fabricated and measured in a thermophotovoltaic radiator/module system (radiator, optical cavity, and thermophotovoltaic module). Results showed that at a radiator and module temperature of 1039°C and 25°C, respectively, 23.6% thermophotovoltaic radiator/module system radiant heat conversion efficiency and 0.79W/cm² maximum thermophotovoltaic radiator/module system power density were obtained. The use of reflective spectral control increased the spectral efficiency and thus the thermophotovoltaic radiator/module system radiant heat conversion efficiency by ∼16% (relative). However, the amount of useful radiation reaching the MIM decreased by ∼7% (relative) compared to using transmissive spectral control. Also, the thermophotovoltaic system radiant heat conversion efficiency and maximum power density using either transmissive or reflective spectral control decreased as the MIM temperature increased. The MIM using reflective spectral control was found to be more sensitive to changes in the MIM temperature than the MIM using transmissive spectral control.