Impact of fin material properties and the inclination angle on the thermal efficiency of evacuated tube solar water heater: An experimental study

In recent years, evacuated tube solar water heaters (ETSWH) have become popular due to their efficiency and low maintenance based on trends in India's solar thermal market. Numerous studies have focused on improving system performance. In the scientific literature, there is a lack of information on the selection of appropriate fin material and the benefits associated with it. The thermal efficiency (It) of ETSWH is directly impacted by the choice of fin material. In this context, the goal of this study was to assess the impact of copper and aluminum using fin material as well as the inclination angle on ETSWH's It. The experiments are conducted for mass flow rate (mwt) varying from 2 to 5l/h. With a mwt of 2l/h, the highest outlet temperature of 55 degrees C was recorded, while the highest It was found at 41.2 degrees C with a mwt of 5l/h. At all mwt, copper fin is more efficient than aluminum fin due to their superior thermal conductivity. Among the considered inclination angles, at an inclination angle of 30 degrees, the efficiency of ETSWH is found to be optimal. ETSWH with a copper fin attains (It = 58.57%), which is more significant than the case when the aluminum fin is used (It = 51.50%).