Thermochemical cooling for high-power chip using sodium acetate trihydrate/expanded graphite: A new strategy and model

Abstract

This study uses thermochemical heat storage (TCHS) material comprising of sodium acetate trihydrate/expanded graphite (SAT/EG) to cool the high-power devices in enclosed space. Due to its extraordinary energy storage density of 785 J/g, SAT/EG effectively reduces the weight/volume of the cooling system. Comparing to using phase change materials, the dummy chip temperature can be maintained less than 160 °C for 18.7 % longer in time. Moreover, a novel thermogravimetric-thermochemical storage (TGTS) model is developed to describe the thermal management process of TCHS. New govern equation adopts the weightloss curve measured by thermogravimetric analysis and directly translates it as a process indicator of the decomposition, thereby omitting the need for correlations of conventional models developed from mechanism functions. As a result, the TGTS model exhibits notable advantages in terms of its simplicity, low programming difficulty, time-efficient preprocessing, and maintains the same level of result accuracy as conventional models (with an average error of 5.19 %). The model can theoretically guide the optimization of the thermal management system by achieving a balance between the decomposition enthalpy and thermal conductivity of SAT/EG under different cooling requirements.