Transient performance of a thermal energy storage-based heat sink using a liquid metal as the phase change material

In this Technical Note, the use of a liquid metal, i.e., a low melting point Pb-Sn-In-Bi alloy, as the phase change material (PCM) in thermal energy storage-based heat sinks is tested in comparison to an organic PCM (1-octadecanol) having a similar melting point of similar to 60 degrees C. The thermophysical properties of the two types of PCM are characterized, revealing that the liquid metal is much more conductive while both have nearly identical volumetric latent heat of fusion (similar to 215 MJ/m(3)). By using at the same volume of 80 mL, i.e., the same energy storage capacity, the liquid metal is shown to outperform significantly over the organic PCM under the various heating powers up to 105.3 W/cm(2). During the heating period, the use of the liquid metal leads to a remarkable extension of the effective protection time to nearly twice longer as well as a reduction of the highest overheating temperature by up to 50 degrees C. The cool-down period can also be shortened significantly by taking advantage of the much higher thermal conductivity of the liquid metal. These findings suggest that liquid metals could serve as a promising PCM candidate for particular applications where the volume limit is very rigorous and the penalty in weight increment is acceptable. (C) 2016 Elsevier Ltd. All rights reserved.