Performance of Solar Water Heater in Akure, Nigeria

Abstract

Solar water heating is a process of tapping energy from the sun for the purpose of raising the temperature of water from local water supply to some desirable higher temperature. Water left in a container and exposed to the sun, has been observed to increase in temperature. However, this natural gain of temperature is not usually efficient; partly because water is a poor absorber of solar energy and partly because a large chunk of energy gain is used in evaporation of water, which will not result into temperature raise. A solar water heater was designed, constructed and tested in Akure, South West, Nigeria (Latitude 7.30^oN and Longitude 5.25 ^oE). A flat plate collector covered with double glazing layers at 20^o angle of tilt to the horizontal was employed. The surface of the collector was darkened to improve its absorption capacity. Readings were taken for a period of six days. With an ambient temperature of 36^oC, a maximum hot water temperature of 73^oC was recorded during the experiment. In addition, hourly collector’s efficiency increased slightly until 2.00 when steep increase was obtained which peaked at 92% at 4.00 pm. The outcome of the experiments established the fact that solar water heater is feasible in South West Nigeria, and of course, in most parts of the country, since insolation is even higher in most other parts of the country, particularly South East and the Northern regions.

Keywords: Solar water heater, insolation, radiation, solar energy, thermosiphon.