Assessment and validation of a numerical model for phase change materials heatsink on thermoelectric devices

Abstract

The use of phase change materials (PCM) in heatsink designs are gaining attention due to its many favorable properties. Some PCM heatsinks designs have been suggested for use with thermoelectric cooling devices (TECs), however, the heatsink designs are often arbitrary where PCM is just added to voids within the heatsink to improve the thermal properties. There is a need to systematically understand the effects of PCM on TEC performance. While a numerical model is key to such systematic study and optimization, the application involves multiple physical phenomena and the resulting model can be prohibitively expensive to run. In this contribution, a numercical model using computational fluid dynamics (CFD) is built to predict the performance of PCM heatsink for use with TECs as cooling wearable. Experiments are calibrated and carried out to prescribe the boundary conditions and ensure that the multiphysics phenomena are accurately captured. The numerical methodology described here can be used for design optimizations of PCM heatsinks to be used in conjunction with TECs. Our numerical model shows that for maximum TEC efficiency, the PCM should be kept at a liquid fraction of less than 40%.