Thermal performance of heat spreader for electronics cooling with incorporated phase change material

The new design of heat spreader, especially addressed to electronics cooling, is described and its basic thermal characteristics are evaluated. It is a kind of pin-fin radiator, but instead if pins the thin wall pipes of small diameter form a heat transfer surface. The pipes are filled with phase change material (PCM). This design combines two important features of heat spreader – high heat transfer surface (due to large number of pipes) and high thermal capacity (which results from the use of PCM). Such a heat sink can be very effective in removing heat from electronic devices in steady states, and simultaneously it can stabilize the temperature of the cooling element in the cases of rapid variations of heat transfer conditions. Thermal characteristics of the device in steady conditions, i.e. overall thermal resistances, were estimated by simple energy balance computations. Thermal performances of heat spreader in transient conditions were determined base on numerical simulation of transient heat transfer in its recurrent part, including melting process of PCM. Temporal temperature variations in crucial points of the heat spreader after simulated failure of fan are presented. These results show the benefits of the use of PCM in the structure of heat spreaders.