Performance assessment of thermoelectric self-cooling systems for electronic devices

Abstract

Due to the development of high-performance electronic devices, there exists a continuous need for effective and efficient cooling systems capable of removing large amounts of heat. A thermoelectric self-cooling system with forced air cooling based on a finned plate heat sink (case-a) and a water cooling based on a microchannel heat sink (case-b) is evaluated through a thermodynamic model. This article investigates the effect of the thermoelement geometry concerning its length and cross-section on the cooling capability of a self-cooling system for a wide range of heat fluxes (10 W to 200 W). Also, the effect of the efficiency related to the DC/DC converter between the thermoelectric generator and pumping devices is included in the analyses. The results show that shorter thermoelements with bigger cross-sections contribute to lower global thermal resistance and lower overheating of the electronic device. However, through the aspect ratio of the thermoelements (δ = cross-section/length), a practical limit was found defining how much shorter the thermoelement must be to satisfy a temperature constraint through the self-cooling condition for different fill factors, which corresponds to δ≤20. Beyond this limit, the performance of the self-cooling system is affected by the low conversion of heat into electricity used to run the pumping devices. The results also demonstrate for δ = 20 and fill factor equal to 0.95, that the temperature constraint (373 K) is satisfied for a heat flux equal to 124 W (case-a) and 173 W (case-b) when the efficiency of the DC/DC converter is 10%. Instead, a DC/DC converter with the highest efficiency (95%) rises the heat flux to 161 W (case-a) and 200 W (case-b), satisfying the constraint. Finally, this article summarizes the maximum heat flux for different thermoelements aspect ratios (δ ≤ 20) and fill factors where the self-cooling system for both cases satisfies a temperature constraint.