Performance of tube heat pipe solar collector with phase change material for seawater desalination system

Abstract

Unlimited seawater resources resulted for utilization of desalination systems using seawater treatment process emerges as a promising technology for addressing the continually escalating need for freshwater. At present, the most notable desalination processes that are reverse osmosis, membrane distillation, multistage desalination, multiple-effect distillation, and electrodialysis, require energy generated by fossil fuels to obtain fresh water. Among the noteworthy sources of renewable energy, solar energy stands out with its manifold applications. The use of solar energy has strong advantages, such as a low maintenance and operation costs. In this study, a novel solar desalination system is introduced, which integrates tube heat pipe solar collector (THP-SC) equipped with phase change material (PCM). The aim of this research is to evaluate the performance of THP-SC equipped with PCM and without PCM. The feedwater sample used is water. Parameters measured for 24 hours were temperature, solar radiation, ambient air temperature, relative humidity, and wind speed. The greatest recorded solar radiation at noon (11.52 a.m.) is 900 W/m2 while the maximum recorded ambient temperature at 12.45 p.m. is 35.2°C. The experimental study showed that from morning to afternoon (06.00-15.00), the temperature of the evaporator section of the heat pipe on the THP-SC without PCM (46.70-56.21°C) was higher than the temperature of the evaporator section of the heat pipe on the THP-SC with PCM (33.18-44.43°C). This is because solar radiation will heat the PCM first before heating the heat pipe. PCM can store heat energy and release it at night. This can be seen from the water temperature in THP-SC with PCM (28.39-36.03) which is higher than the water temperature in THP-SC without PCM (27.17-34.01) at night, but the temperature difference is not significant. This can be caused by the large amount of heat lost to the environment in THP-SC with PCM, it is best to coat the heat pipe tube with insulation and create a vacuum to reduce heat loss.