Sustainable and renewable energy management by investigating the effect of the diameter of finned tubes of a solar collector on its heat production in the presence of phase change materials in a residential building

This paper examines a flat-plate solar panel numerically. Phase change material (PCM) is used at the bottom of the collector to store solar energy. Three tubes are placed inside the PCM, on each of which a number of fins are installed. A transient study is performed in a period of 1000 s for three tube diameters of 4, 6, and 8 cm. The aim is to evaluate the collector temperature, PCM phase, water inlet temperature, and the amount of thermal energy generated by the collector for domestic hot water. This numerical study is done using the finite element method. Using a larger diameter can cool the collector but make the outlet water temperature slightly lower. The use of tubes with 4 and 6 cm in the collector causes the whole PCM to become molten in a short time, but the use of a tube with 8 cm causes the molten PCM to remain constant for a while and no other phase change occurs in the PCM, resulting in some of the PCM remain solid. A tube with a diameter of 8 cm can generate the maximum amount of heat in the collector and the maximum amount of heat received from the sun is 483 W.