DESIGN AND FABRICATION OF A SOLAR WATER HEATER FOR DOMESTIC USE.

ABSTRACT

Solar energy is a powerful source of energy that can be used to heat, and light homes and businesses. It is a renewable form of energy and the various utilization process is environmentally friendly. The amount of sunlight that strikes the earth's surface in an hour and a half is enough to handle the entire world's energy consumption for a full year. The energy of the sun reaches earth radiation as it involves no medium to technically transfer the heat. Solar energy can be harnessed for various uses e. g electricity, heating and other various applications through. The major setups for harnessing solar energy are Photovoltaic cells and the solar water heater, the Photovoltaic cells convert the thermal energy of the sun to electricity while the solar water heater uses the thermal energy of the sun to heat water for domestic and industrial use. This work is based on the design of a solar flat plate collector for domestic use. The work is based on a renewable energy source, which is solar thermal energy. The potential of solar thermal energy in meeting the increasing demand for hot water coupled with energy Crisis, with fossil fuels depleting and concerns about climate change and pollution, there is a growing need to explore sustainable and renewable energy sources.Solar water heaters use solar collectors to absorb sunlight and convert it into heat energy. This heat is then used for water heating purposes, reducing the need for electricity or other forms of conventional heating. The solar water heater consist of two major units called the flat plate solar collector unit and the circulatory unit.The flat plate collector unit consist of the absorbing surface which is made from aluminum and painted black to maximize solar energy absorption, double transparent glass cover made from transparent green glass, saw dust was used as thermal insulation because of it's low thermal conductivity and the overall casing was made from wood to prevent heat losses from the solar water heater setup. The flat plate collector was designed to heat 20 litres of water, and serve a family of five consisting of 2 Adults and 3 children. The performance testing was carried out in a period of 3 days, spanning from 15th-17th of September 2023. And the fluid outlet temperature achieved was 60°C and the thermal efficiency of the solar water heater was 64% at minimum and 75% at maximum. A comparison of the collector efficiency and the co- efficient of performance shows that the collector efficiency increases with decrease in co-efficient of performance. It was also noted than the largest fraction of useful heat gain by the collector was delivered during periods of high radiation corresponding to when highest temperatures were recorded.