Utilization of paraffin wax as phase change material for solar thermal energy storage

In this work, a thermal energy storage system based paraffin wax as phase change material (PCM) was designed, constructed and tested when it was integrated with a solar water heater (SWH). For the purpose of comparison, the SWH was also tested when water was used as a storage medium. The system was tested for successive days at different mass flow rates of the heat transfer fluid varied from 0.08 to 0.16 kg/s. The maximum energy stored in 110 kg of water used as storage material is 15.9 MJ/day, compared to 11.9 MJ when 50 kg of paraffin wax was used as storage material. This means that the PW not only capable of store 75% of the energy stored in water per day but also it achieves a 50% reduction in the storage volume. The low storage temperature gives also more superiority to the wax as storage material especially in the domestic application where just warm temperature is needed.