Experimental study on spiral flow passive solar water heater

This study presents the experimental analysis of spiral flow flat plate collector passive solar water heater. A solar water heater was fabricated with spiral shaped copper water tube fixed on the flat plate aluminium absorber plate. The experiments were conducted at Kovilpatti (9°10′ N, 77°52′ E), India, during summer. Variations in exit water temperature and efficiency of the system were studied for different mass flow rates. Around 2 pm, the system reached the maximum efficiency point. The maximum efficiency of the system was 65.98% at 0.015 kg/s mass flow with exit water temperature of 95°C when the ambient temperature was 36°C.