Effect of nonuniform solar radiation on the performance of solar thermoelectric generators

Abstract

Solar radiation must be concentrated before irradiating hot sides in solar thermoelectric generators (STEGs) to increase the temperature difference between hot and cold sides and thus enhance output performance. However, concentrated solar radiation is often nonuniform. This condition affects the output performance of STEGs. Herein, a thermal–electric coupled model of STEGs was constructed to investigate the thermoelectric performance of STEGs under nonuniform solar radiation. Results demonstrate that when the concentration ratio is low, increasing nonuniformity facilitates the increase in the output power of STEGs. When the concentration ratio is 60, output power increases by a maximum of 3.05 %, whereas the average temperature difference decreases by 4.44 K. When the concentration ratio is high, STEG output power peaks under a specific nonuniformity, and some thermoelectric legs at the edges of STEGs turn into load, affecting the overall STEG output performance. When the cold-side cooling performance is poor, the solar radiation input to STEGs should be made as uniform as possible to ensure the output performance and safe operation of STEGs. The results of this study provide guidance for the design of efficient STEGs.