Investigation of thermal radiation effects on thermoelectric module performance by an improved model

摘要

Thermal radiation in thermoelectric modules (TEMs) has the potential to significantly affect their performance when they operate under high-temperature conditions. Here, to accurately investigate the thermal radiation effects on TEM performance, an improved 3D thermal-electric coupled model is developed. The radiative heat losses, which occur on all the exposed surfaces of thermoelectric legs, substrates, and electrodes in TEMs, are included in the improved model. These heat losses are ignored or considered incompletely in the previous TEM models. The improved model is validated against available experimental and numerical results. Then, effects of the hot-junction temperature, surface emissivity, the geometries, and configuration of TEM on the performance variation caused by radiative heat losses are analyzed. Results reveal that neither the thermal radiation via the substrates' surfaces nor that via the TE legs' surfaces can be neglected to accurately estimate the performance of TEM with high temperature. Thermal radiation has a greater effect on the efficiency of cylindrical-TEM than that of rectangular-TEM. The thermal radiation effect on TEM performance becomes more severe with increasing length and leg separation along with decreasing leg cross-sectional area. The decrement of conversion efficiency due to radiation heat losses is as high as 52.7% for the studied cases.