Experimental Investigation of Thermal Performance in an Advanced Solar Collector with Helical Tube

This paper reports the thermal performance of a new cylindrical solar collector based on an experimental investigation with the difference that instead of the collector tube with absorbent coating, coil into a helical copper tube is placed in the center of the collector. Because of the helical shape of the tube, without any change in the heat transfer area, heat transfer increases. In this case, the centrifugal forces generated secondary flow, increases the coefficient of the convection heat transfer. Another advantage of this type of collector with respect to the flat plate collector, is its circular shape that is constantly exposed to sunlight. Inlet and outlet temperatures of the cylindrical solar collector was measured, during September 6-8, 2012 from 10 AM to 14 PM, and the thermal efficiency was between 43.5 and 58.7 percent. The results of this article can be useful for analysis of the solar energy systems.