The role of vegetable oil in water based phase change materials for medium temperature refrigeration

This research aims to investigate development of water based phase change materials (PCM) for cold thermal energy storage (CTES). Mixtures of water with small amount vegetable oil addition were chosen as candidates of the PCM that were considered to be suitable for medium temperature refrigeration application with temperature range of products between −1 °C and +5 °C. The PCM candidates were tested experimentally through DSC and T-history method. The results showed that esters of vegetable oils played very important role on the solubility of the vegetable oil in water. The esters made the investigated vegetable oil (soya oil or corn oil) mix well in water solutions and they worked as nucleating agents that could lower freezing point and reduce super-cooling of the water. It was found that addition of vegetable oils by 5% to 10% in water solution could decrease the freezing temperature from 0 °C down to respectively −3.5 °C to −6.5 °C and could also minimize degree of super-cooling of the PCM candidates.