Heat transfer and opto-electrical conversion evaluation on a GaSb thermophotovoltaic system

Thermophotovoltaic (TPV) utilize photovoltaic effect to convert thermal radiation from a heat source into electricity. A radiation-conduction coupled heat transfer model is established for a compact distributed thermophotovoltaic module, incorporating semi-transparent radiative properties and spectral absorption selectivity of the photovoltaic cell and optical window. Discrete ordinates method and multi-band spectral model is employed for the radiative transfer simulation, while the energy equation is solved by the finite volume method. The radiation energy and temperature field within the system are obtained, consequently the conversion efficiency of TPV cell is determined. The influencing factors such as system configurations (upright vs. offset), emitter temperature and dimension, convective cooling level, and spectral selectivity of emitter are discussed. Results demonstrate that the features and output performance exhibited by two configurations (upright vs. offset) have negligible difference. A superior efficiency of 25.71 % is achieved at 1200 K while emitter temperature ranging from 800 K to 2000 K. Temperature of TPV cell has an exponential increase from 305 K to 441 K as the emitter temperature increases. Using selective optical window and reflector can elevate the efficiency by 0.84 ∼ 4.78 % under high-temperature operation. Intense convective cooling of cell and spectral selectivity design of emitter can substantially improve the system performance.