Thermoelectric generators (TEGs) have been considered as a promising technology for waste heat recovery owing to energy depletion and environmental pollution. Properties of a thermoelectric module (TEM) affect the TEG system performance essentially. This research investigated the optimal operation conditions of a TEM under steady state by experiments to achieve superior performance. The impacts of clamping force and interface material thickness on the characteristics of a TEM with given heat and cold source temperature are analyzed in detail. Results indicate that increased pressing force diminishes the contact thermal resistance and enhances the heat conduction. The maximum stress that a module can withstand should also be taken into account. In addition, graphite layers material replaces the air gaps between interfaces on account of its compressibility, which conduce to higher thermal conductivity. However, the thermal resistance of graphite material increases with excessive thickness as well. From the analysis above, it can be concluded that the optimal operation conditions of the TEM in this test are the clamping force from 2.5 kN to 3.7 kN and the graphitic layers thickness of 0.8 mm.
Keywords thermoelectric module, experimental test, optimal operation conditions, output power