Numerical and experimental analysis on thermal energy storage of polyethylene/functionalized graphene composite phase change materials

Abstract

The main driving force behind the present work is environmental issues caused due to the usage of plastics, and energy issues. Current work attempts to address these problems by converting recycled plastics into thermal storage materials (TSM). Unfavorable thermophysical properties of plastic make it impractical but these inadequacies can be amended by blending with additives of superior thermophysical properties like, functionalized graphene. Numerical and experimental analysis are carried out to assess the thermal performance of TSMs (LLDPE, CPCM-1, CPCM-2 and CPCM-3) and check the compatibility of the materials. The phase change temperature of TSM is 123 to 125 C and heat of fusion is 71.95 to 97 kJ/kg. Several thermal characteristics are analyzed to assess thermal performance and the amount of heat energy supplied, rate of heat transfer, and heat storage efficiency are deliberated. Results shown energy level enhancement of 43.17, 50.42, 54 and 50.61% for LLDPE, CPCM-1, CPCM-2 and CPCM-3 respectively. Among the TSM CPCM-2 shows relatively better storage capability (54% enhancement) due to incorporation of optimum concentration of enhancing material. The solidification process takes place through convection and radiation mode of heat transfer, at the completion of solidification process the TSM energy content reduces to 97.5, 96, 96 and 96% for LLDPE, CPCM-1,CPCM-2 and CPCM-3 respectively. This work concludes that, recycled plastics can be blended and it can be converted into efficient thermal storage material. 2019 Elsevier Ltd