Development of sunlight-driven eutectic phase change material nanocomposite for applications in solar water heating

Abstract

Organic phase change materials (PCMs) have been utilized as latent heat energy storage medium foreffective thermal management. In this work, a PCM nanocomposite, consisting of a mixture of two organicPCMs (referred to as eutectic gel PCM) and minimal amount (0.5 wt%) of nanographite (NG) as asupporting material, was prepared. Differential scanning calorimeter was used to determine the meltingtemperature and latent heat of pristine PCM, paraffin (61.5 °C and 161.5 J/g), eutectic gel PCM (54 °C and158 J/g) and eutectic gel PCM nanocomposite (53.5 °C and 155 J/g). The prepared PCM nanocompositesexhibited enhanced thermal conductivity and ultrafast thermal charging characteristics. The nanocompositeswere employed for two different applications: (i) providing hot water using an indigenously fabricatedsolar water heating (SWH) system and (ii) solar rechargeable glove that can be rapidly warmedand used. Experimental results on SWH system show that the use of PCM nanocomposites helps to increasethe charging rate of PCM while reducing the discharging rate of heat by PCM to water, thus enhancingthe maximum utilization of solar energy and hence improving the efficiency of the SWH system.The experimental results on solar rechargeable glove revealed that the glove has the ability to retain thetemperature up to 3 hours.