Thermal conductivity enhancement of phase change materials using aluminium wool

Phase change materials (PCM) offer a solution to bridging the energy gap between energy use and energy availability. These materials store energy in the form of latent heat, which is the heat required to convert a solid into a liquid, without a change in temperature. This physical process is completely reversible and allows energy to be stored in a dense, safe and convenient way. One of the major drawbacks which limits the practical application of many organic PCMs is their low thermal conductivity, many researchers have lead focused investigations into a number of thermal conductivity promoters to help improve their thermal characteristics, but very few have been commercially viable. This paper presents a practical study on the thermal conductivity enhancement of organic phase change material using randomly packed aluminium wool and discusses the practical reality of applying this technology. A number of composite PCM samples were created, each using the same base PCM and different weight percentages of thermal conductivity promoter. The composite PCMs were tested using differential scanning calorimetry (DSC), T-history method and the thermal conductivity was measured. The performance of each composite PCM was then compared and discussed. It was found that composite PCM had an improvement in thermal conductivity by up to 70.8%. Their freezing and melting rates improved by up to 167.7% and 68% respectively. This gain in thermal performance was at the expense of the samples latent heat capacity.