Performance enhancement of solar water heater using compound parabolic reflector and numerical simulation of thermal losses

Abstract

The purpose of this project is to design, fabricate and test the performance enhancement of a SWH with compound parabolic reflector (CPR). The advantage of this system is that there is no need of a sun tracker. Firstly, the experimental work is done by comparing the performance of two evacuated tube collectors, out of which one is equipped with a CPR at the bottom surface. Secondly, an ANSYS simulation is done to find the effect of thermal loss on the performance of the system. For almost all of the SWH which are commercially available, only the top portion of the evacuated pipe is used for absorbing the solar radiation. The shaded portion remains unused. A CPR uses a mirror in the shape of a compound parabola to reflect and concentrate sun radiations towards a receiver tube located at the focus line of the compound parabolic reflector. Thus the whole cylindrical surface of the evacuated pipe is made useful and the absorber surface absorbs the incoming radiations and transforms them into thermal energy. Thermal losses will occur mainly due to radiation and even though the system uses an evacuated tube collector, a small amount of loss occurs due to convection. Thus a thermal loss analysis around an evacuated tube collector is performed.