Comparative Performance of Cylindrical Solar Water Heating System With and Without a Reflective Surface

The comparative performance of a cylindrical solar water heating system with and without reflective surface is presented. The major components of the water heater are a transparent cylindrical PVC material acting as the glazing and a copper tube painted black for improved solar energy absorption. One of the systems has it’s under segment, about 45°, lined with an aluminium foil to act as a reflective surface. The two systems were tested under the meteorological condition of the Federal University of Technology, Owerri, Nigeria. Results obtained reveal a maximum exit water temperature from the solar water heater of 68 and 50°C for the reflective and non reflective surface conditions, respectively. The maximum efficiencies were determined as 70% and 40%, respectively for the reflective and non reflective surface conditions while the Hottel-Whillier-Bliss characterization showed that addition of the reflective surface improved the solar water heater’s ability to absorb energy by about 100% and reduced the rate at which it loses by up to 25%. Thus the system with a reflective surface has better capability of converting solar energy to heat for hot water generation.