Experimental study and modeling of a thermoelectric generator heated by concentrated solar energy

Abstract

The studies of renewable energy have drawn a lot of attention due to the increasing serious energy and environment crisis. Among them, thermoelectric generator is an attractive topic which could directly transfer heat energy to electricity through a compact module. The heat-electricity conversion is possible under residential conditions. In this study, a solar thermoelectric generator (STEG) combined with parabolic concentrator is designed and a simplified prototype was investigated experimentally. Heat transfer oil layer between inner and outer shells is employed to homogenize the temperature filed in circumferential direction and enhance the heat transfer. Flexible heating plates were used to control and simulate the input power in the experiments. The temperature field in oil layer and inner shell were evaluated through experimental studies. A computational model based on 2-D differential equations and standard simplified thermoelectric model has been developed. Through experiments, temperature homogenization and heat transfer enhancement effect by oil layer have been observed. The convection heat transfer coefficient at steady state was estimated to be 320 W/(m 2 • K) through the combination of model and experimental data. An iteration method based on the computational model was employed to predict the system output. Through closed-circuit experiments, the output power of 0.3W, 0.33W and 0.26W were obtained in bottom, middle and top part respectively in critical power points. And the iteration method shows good agreement with the experimental results. Through simulation, it is found that adjusting the number and distribution pattern of TEMs could further raise the output power and eliminate the temperature mismatch.