IR thermography for the assessment of the thermal conductivity of Thermoelectric Modules at intermediate temperature

摘要

The correct measurement of the performances of thermoelectric (TE) modules for energy conversion is a mandatory task both for laboratory research and for industries engaged in TE modules development or in their integration into thermoelectric generators. A testing device oriented to the maximum flexibility, based on the heat flow meter method at the cold side of the module has been developed. The system is conceived to test TE modules (single or in cascade) with a footprint up to 60×60 mm~2, from room temperature up to intermediate temperature. Modules can be tested under vacuum or inert atmosphere. Specifically, the flow meter is made of a block of material, with known thermal conductivity, in contact with the cold side of the thermoelectric module. The heat flow is finally determined by measuring the temperature profile along the heat flow path and that is obtained by IR thermography. DR. thermography is also utilized to evaluate the contact resistance between the active thermoelectric elements made of ceramic materials and the ceramic layer working as heat diffuser and mechanical support. Some finite element thermal analyses of the system performed for its design are presented.