Method and Apparatus for Determining Operational Parameters of Thermoelectric Modules

Abstract

The main aim of this work was to construct and test an apparatus for characterization of high temperature thermoelectric modules to be used in thermoelectric generator (TEGs) applications. The idea of this apparatus is based on very precise measurements of heat fluxes passing through the thermoelectric (TE) module, at both its hot and cold sides. The electrical properties of the module, under different temperature and load conditions, were used to estimate efficiency of energy conversion based on electrical and thermal energy conservation analysis. The temperature of the cold side, T c , was stabilized by a precise circulating thermostat (£0.1°C) in a temperature range from 5°C to 90°C. The amount of heat absorbed by a coolant flowing through the heat sink was measured by the calibrated and certified heat flow meter with an accuracy better than 1%. The temperature of the hot side, T h , was forced to assumed temperature (T max = 450°C) by an electric heater with known power (P h = 0-600 W) with ample thermal insulation. The electrical power was used in calculations. The TE module, heaters and cooling plate were placed in an adiabatic vacuum chamber. The load characteristics of the module were evaluated using an electronically controlled current source as a load. The apparatus may be used to determine the essential parameters of TE modules (open circuit voltage, U oc , short circuit current, I sc , internal electrical resistance, R int , thermal resistance, R th , power density, and efficiency, g, as a function of T c and T h ). Several commercially available TE modules based on Bi 2 Te 3 and Sb 2 Te 3 alloys were tested. The measurements confirmed that the constructed apparatus was highly accurate, stable and yielded reproducible results; therefore, it is a reliable tool for the development of thermoelectric generators.

Synthesis and Characterization of Antimony Telluride for Thermoelectric and Optoelectronic Applications

“…The ZT value increases when the Seebeck coefficient and the electrical conductivity increases and the thermal conductivity decreases [1]. Thermoelectric module build from p-and n-type materials allowed to direct energy conversion, but due to low efficiency of commercially available modules [2] researchers try to modify properties of know materials and in the same time search for a new one. Antimony telluride Sb 2 Te 3 has been commonly applied for many years as a low-temperature thermoelectric material, because of its relatively high value of ZT parameter (close to ~1).…”

International Round Robin Test of Thermoelectric Generator Modules

“…The few reports on the application of custom-built GHPs for TEM characterization can be split into concepts with passive thermal insulation and active temperature guarding of the MH. Montecucco et al [ 92 ], Sandoz-Rosado et al [ 93 ], and Zybala et al [ 94 ] described GHP apparatuses with passive thermal insulation of the MH and proposed a correction of its measured power by estimates of heat losses to the environment.…”

“…Zybala [ 94 ] described an apparatus comprising two independent methods for heat flow determination. Besides a GHP, which was used as a heat source, Zybala determined additionally the outgoing heat flow at the cold side of the TEM, similarly to Hejtmanek [ 71 ], from the specific heat, flow rate, and temperature difference between the coolant in- and outlet in the heat sink.…”

The Properties of Bi2Te3-Cu Joints Obtained by SPS/FAST Method

“…Joints that do not fulfil the above requirements significantly reduce the TEM parameters such as power density and energy conversion efficiency. 7 The produced joints must also fulfil mechanical requirements, such as good tensile strength and a thermal expansion coefficient close to those of the joined materials. 8 Overall module efficiencies also have a significant impact on metal-ceramic junction properties 9 and on the type of insulating ceramics used.…”