Study of a complete thermoelectric generator behavior including water-to-ambient heat dissipation on the cold side

Abstract

The reduction of the thermal resistances of the heat exchangers of a thermoelectric generation system (TEG), leads to a significant increase in the TEG efficiency. For the cold side of a thermoelectric module (TEM), a wide range of heat exchangers has been studied, form simple finned dissipators to more complex water (water-glycol) heat exchangers. As Nusselt numbers are much higher in water heat exchangers than in conventional air finned dissipators, convective thermal resistances are better. However, to conclude which heat exchanger leads to higher efficiencies, it is necessary to include the whole system involved in the heat dissipation, that is, TEM-to-water heat exchanger, water-to-ambient heat exchanger, as well as the required pumps and fans. This paper presents a dynamic computational model able to simulate the complete behavior of a TEG, including both heat exchangers. The model uses the heat transfer and hydraulic equations to compute TEM-to-water and water-to-ambient thermal resistances, along with the resistance of the hot side heat exchanger at different operating conditions. Likewise, the model includes all the thermoelectric effect with temperature-dependent properties. The model calculates the net power generation at different configurations, providing a methodology to design and optimize the heat exchange in order to maximize the net power generation for a whole variety of TEGs.