Characteristics of gradual discharging process on a thermosyphon SWH tank containing PCM

This paper aims to reveal the characteristics of thermal energy release in a solar water heater (SWH) tank involving phase change materials (PCM) as thermal energy storage material. A bundle of cylindrical capsules was inserted in 31.37 liters of SWH tank. The capsule contains paraffin wax as latent type heat storage. K type thermocouples were mounted on the water side and the PCM side. Experiments was begun with the charging process using solar energy until water temperature exceeds the melting temperature of PCM. After that, a gradual discharging process is done to release the thermal energy from the tank. The SWH tank containing 17.3 liters of water can produce 60 liters of hot water with an average water temperature of 45.13 °. This condition is achieved when the average daily radiation intensity is 699.92 W/m2. The PCM has contributed in storing thermal energy during the discharging process.