Superior Long-Term Performance of Composite Phase Change Material with High-Density Polyethylene under Thermal Aging Process

Abstract

Protecting the phase change material (PCM) from thermal aging is done by using polyethylene (high-density/HDPE) as supporting matrix. The HDPE content is set at 5 wt%, 10 wt% and 15 wt%. The composite PCM (cPCM) is treated through repeating melting/solidification process up to 10,000 cycles which is conducted between temperature 55℃-65℃. The thermal capacity of the paraffin wax (PW) is reduced notably, where enthalpy of fusion is decreased from 145.92 J/g to 138.46 J/g. The cPCM with 10 wt% and 15 wt% HDPE maintain a notable performance with only reduces slightly from 130.7 J/g to 129.7 J/g and 127.7 J/g to 127.2 J/g, respectively. The supercooling degree of PW increases around 1.64℃, which accelerates the cooling rate to 4.81℃/min. The HDPE in the cPCM maintain the physical behavior of PW, which minimizes the shrinkage effect during solidification. The highest heating rate is found at 2.29℃/min with minor decrement (0.06℃/min) for cPCM 15 wt% HDPE after treatment. The finding from this work can be used for fundamental basis to develop a high cycle PCM which able to operate at extended cycle with minor supercooling degree that is suitable for temperature sensitive operation.