Experimental study of a building integrated solar water heater

Solar thermal technologies have a special relevance for countries which have a scarcity of conventional fuel resources but have good solar potential i.e. radiation about 4.5-6 kWh/m²/day with an average of 280 clear days. A judicious use of solar energy for water heating and cooking can cut down conventional fuel consumption and can solve the problems related to economy, ecology, environment, air pollution global warming and public health arising due to currently-used fuel. Among various solar thermal appliances solar water heating systems have reached technical maturity and are used in many countries. But still domestic solar water heaters are not in the range of purchasing capacity of the mass population of developing countries like India. It is estimated in different studies that building integrated solar thermal systems have become 40% less expensive than conventional solar thermal installations. Therefore, this present study focused on the development of building an integrated solar thermal system. An experimental study of a building integrated solar water heater has been performed and presented in this paper. Due to building integration, water heating systems are highly weather resistant. The experiments were conducted at the University of Rajasthan, Jaipur, over a number of days. In these experiments, the solar radiation intensity (Is) on a horizontal surface was measured using a pyranometer and temperature of inlet (Tin), outlet (Tout) and ambient (Ta) were measured through temperature data logger. The measurements of temperatures were carried out on clear sunny days for the duration of 10:00 to 14:00 Indian Standard Time (IST) with single and double poly (methyl methacrylate) (PMMA) glaze sheet. The maximum outlet water temperature obtained was 74ºC in open and closed loop testing. The poly (methyl methacrylate) (PMMA) as glaze is found to be the promising option to increase efficiency and durability of solar water heater.