Development and performance test of an evacuated tube solar water heater

Abstract

The climate change because of global warming and worldwide energy scarcity are prompting almost all the countries of the world to look for alternate energy sources like nuclear and renewable. Because of infrastructure and other reasons, developed countries can tap into nuclear energy but developing country like Bangladesh is not fortunate enough to have that option. Consequently, the only option that is left open to developing countries is renewable energy. Among renewable energy solar, wind, hydro, geo-thermal and wave energies are most reliable, which do not cause carbon emission. Solar energy can be used in many purposes like water heating, air heating etc. Among the various types of solar collector, evacuated tube solar collector is one of the most effective water heating device. An evacuated tube solar water heater was constructed from locally available materials and investigated in the department of Mechanical Engineering of KUET. In the first attempt, the highest. storage tank temperature obtained was only 47°C. In the present attempt, cylindrical parabolic reflectors were placed under each evacuated tube. Consequently, the maximum water temperature obtained at outlet to collector was 81°C and 76°C in the storage tank in the month of April-May.