Publication

Abstract : The demand for energy is increasing worldwide and the best way to meet this demand is a clean renewable energy source. Among the various options available, solar energy can be considered as the best renewable energy source. This paper deals with design, fabrication, and performance study of a solar air heater coupled with evacuated tubes and heat pipes. Heat pipes are used to absorb the solar energy and evacuated tubes are used to prevent the convective losses. A selective absorber coating is used to coat the inner side of the evacuated tube. Air is forced in to the duct of size 10 cm × 10 cm by a fan, which is driven by a photovoltaic panel. Six heat pipes and six evacuated tubes are used to absorb the solar radiation. A solar flux meter is used in to measure incoming solar radiation. Experiments are conducted with and without evacuated tubes. For both the configurations, the variations of thermal efficiency with respect to time have been reported. The maximum thermal efficiency obtained is 35% for evacuated tube with heat pipe. The average efficiency of evacuated tube with heat pipe is 1.5 times that of heat pipe alone