An experimental investigation of a novel pcm-embedded solar water heater

The performance of Solar Water Heaters (SWHs) is enhanced with the incorporation of Phase Change Materials (PCMs) in a tank to increase storage capacity and extend heating time beyond regular sunshine periods. The goal of this study is to investigate the effect of incorporating a PCM in a passive SWH tank with two different designs. The selected PCM is paraffin wax which suffers from low thermal conductivity, rendering the heat capture and release very slow. Therefore, both designs feature a high heat transfer between the PCM and water by encapsulating the PCM in straight tubes or coils. After a numerical study on both designs, the tube configuration is experimentally tested to validate numerical results during charging and discharging. The excellent agreement between experimental and numerical results demonstrates the usefulness of implementing such systems in residential SWHs. The system was able to fully melt the PCM within 3 h on a clear-sky day in June, in Byblos Lebanon. Then, the heat extraction during discharge was completed in less than 1 h, increasing the water temperature by around 20 degrees C. The energy storage capacity of the tank increased from 11.02 to 12.92 MJ, achieving a thermal efficiency of 64.5 %.