Transition Temperature Stratified Thermal Energy Storage Systems Applied to On-Demand Cooling of High Power-Density Hand-Held Electronics

A thin-slab thermal storage volume that is sandwiched between a hand-held unit’s skin and a heat spreader that is in thermal contact with the electronics is analyzed. The storage volume is assumed to be filled with a conductivity enhanced, “dry” phase change material. Three storage volume configurations are considered. Configuration I is a single phase change material transitioning at one temperature. Configuration II is a two-layer system with phase change material-1 in thermal contact with the heat spreader and phase change material-2 in thermal contact with the unit’s skin. Configuration III consists of several layers, such that the phase transition temperature varies across the volume. A finite element model is built and numerical simulations provide temperature responses for each configuration. Results show that by employing a stratification of transition temperatures, relative to a non-stratified storage volume, up to a 20% decrease in recovery time is realized. Furthermore, utilization of two or more transition temperatures results in improved temperature control.