Performance comparison of near- and far-field temperature-dependent thermophotovoltaic systems with tungsten emitter and GaxIn1-xAs cell

Abstract

The near-field effect greatly increases the radiative heat flux. The enhanced radiative heat flux results in increasing heat production in photovoltaic cells. A temperature-dependent model of the near-field thermophotovoltaic cell (TPVC) with a tungsten emitter and a GaxIn1-xAs cell is established and optimized to compare the performances of far- and near-field TPVCs, in which the temperature-dependent band-gap energy and dielectric function as well as finite-time heat transfer between the photovoltaic cell and the environment are all taken into account. The effects of voltage, emitter temperature, heat transfer parameter, and mole fraction of Ga on the performance of TPVCs are analyzed. It is found that the maximum power density of the near-field TPVC is above three times of that of the far-field TPVC, while the cell temperature at the maximum power density in the near-field TPVC has risen by 14.7 K in comparison with that in the far-field TPVC even if the heat transfer parameter is as high as 9.5 W/(cm2 K). The performances of the near-field TPVC are more affected by the heat transfer parameter than those of the far-field TPVC. When the heat transfer parameter is reduced to 1.5 W/(cm2 K), cell temperature in the near-field TPVC is increased by 126 K and the maximum power density is decreased by 5.43 W/cm2, while in the far-field TPVC, the cell temperature is increased by 40 K and the maximum power density is decreased by 0.68 W/cm2. Moreover, it is pointed out that increasing the emitter temperature, decreasing the cell temperature, and selecting the suitable mole fraction of component Ga in GaxIn1-xAs are some effective approaches to boost the power density and efficiency of far- and near-field TPVCs.