Analysis of a photon-recycling optical cavity in a cylindrical thermophotovoltaic system considering thermal load in cells

Abstract

Thermophotovoltaics (TPVs) hold immense promise for efficient heat-to-electricity conversion via photons, particularly considering advancements in photon-recycling techniques. We investigated the design of an optical cavity for a TPV system in which the emitters were radially surrounded by cells, with the goal of applying the photon-recycling effect in practical TPV systems. Employing ray-trace simulations, we explored the influence of various parameters on TPV system performance. The optimal optical cavity was designed with the same area of emitter and cell under a constant cell temperature. Incorporating the thermal behavior of the cell into the simulation model yielded significantly different system efficiencies, emphasizing the importance of temperature considerations. Despite some discrepancies, experimental validations and theoretical analyses described the thermal behavior of gallium antimonide cells. Optimization under different conditions indicated a potential for the system efficiency of these cells to exceed 40 %. To further enhance the performance of TPVs, future efforts should focus on increasing the cell’s out-of-band reflectance, improving cooling, and optimizing area ratios for specific cell reflectance and heat dissipation situations. This study provides essential insights into the comprehensive design of a TPV system with an optical cavity by combining photon-recycling and the temperature dependence of the cell.