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B1: Contacting and insulation
Abstract
Thermoelectric generators are composed of many parts. When subjected to thermal loads, the effect of thermal contact resistance at the interface must be taken into consideration in order to accurately analyze their thermal behavior. Thermal contact resistance significantly varies with surface roughness; it is also affected by thermal conductivity, interface pressure and surface hardness of the joint materials. Our target materials are common thermoelectric component materials, such as aluminum alloy and ceramic.
In previous works, the thermal contact resistance involving dissimilar materials has been reported [1, 2], however, the specific behavior associated to practical thermoelectric engineering applications has been hardly studied. The first objective of this paper is to design and develop a thermoelectric generator test bench intended to study the thermal contact resistance. Secondly we have tested four heat extenders with different surface roughness and we have calculated the thermal contact resistance between the thermoelectric module ceramic layer and the heat extender surfaces. Besides, the experimental data has been compared with a computational model results obtaining high accuracy,
Finally, using the experimental data, an empirical equation to estimate the thermal contact resistance in function of the roughness has been proposed for the purpose of thermoelectric applications. This equation correlates closely with the experimental data.
[1] Fukuoka, T., Masataka, N., Evaluation of Thermal Contact Resistance at the Interface of Dissimilar Materials, Journal of Pressure Vessel Technology 2013, vol. 135, 021403, 7pp.
[2] Rogers, G.F.C., A. Heat Transfer at the Interface of Dissimilar Metals. Int. J. Heat Mass Transfer, 1961, 2, pp. 150–154.