Performance assessment of thermoelectric self-cooling systems for electronic devices. (5th July 2021)

• Record Type: Journal Article
• Authors: Di Capua H, M.; Jahn, Wolfram
• Is Part Of: Applied thermal engineering. Volume 193(2021)
• Publication Date: 2021-07-05
• Subjects: Thermoelectric generator -- Self-cooling -- Heat sink -- Electronic device, Thermodynamic model; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2021.117020
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Lowest overheating achieved with self-cooling based on a microchannel heat sink. High dissipation with minimum pumping power. Lower global thermal resistance with shorter thermoelements and bigger cross-section. Practical limit: Thermoelements length should not 20 times smaller than cross-section. Cooling capability highly affected by the efficiency of the DC/DC converter. 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.