Experimental Study on Paraffin Wax and Soya Wax Supported by High-Density Polyethylene and Loaded with Nano-Additives for Thermal Energy Storage

Thermal energy storage technology has evolved as one of the prominent methods of storing thermal energy when it is available and utilized as per the requirements. In recent years, thermal energy storage has found a variety of applications for thermal management, such as buildings, batteries, electronics, cold storage, textiles, and solar thermal systems. Phase Change Material (PCM) has taken the lead among all other thermal energy storage materials because of various merits such as high energy density, ease of use, low cost, low volume change, environmental friendliness, easy availability, and chemical stability. However, limitations such as poor thermal conductivity and leakage during phase transformation limit their applicability. In this study, Shape Stabilized Composite PCM (SSCPCM) was developed to overcome these drawbacks. Paraffin wax and soya wax were used as PCMs and multi-walled carbon nanotubes and graphene oxide were used as nano-additives. High-Density Polyethylene (HDPE) is used as a supporting matrix. Leakage test suggest maximum loading of 40 wt% and 35 wt% of paraffin wax and soya wax in HDPE without any leakage at elevated temperature. The prepared SSCPCM shows substantially better thermal energy storage capacity along with improved thermal conductivity. A maximum rise of 260.8% in thermal conductivity was observed in paraffin wax supported by HDPE and loaded with 3 wt% of multi-walled carbon nanotube nanoparticles. The heating and cooling performance suggests an improvement in the heating and cooling rate by adding nano-additives. The prepared SSCPCM are also thermally stable at elevated temperatures up to 150 °C.