CHAPTER ONE INTRODUCTION 1.1 Background of the Study Renewable energy resources of which the sun is a good example, are those resources which undergo a faster replenishment rate within a relatively short time than the rate at which they are utilized or depleted. The energy of the sun is generated from the nuclear fusion of its hydrogen into helium, with a resulting mass depletion rate of approximately 4.7 × 106 tons per second. The earth’s population currently needs 15 TW of power in total, but the solar radiation that reaches the earth on a continuous basis amounts to 120,000 TW; hence, just a fraction of the suns energy reaching the earth will cover the bulk of energy requirements (Bradke et al., 2011). Solar energy being transmitted from the sun through space to earth by electromagnetic radiation must be converted to heat before it can be used in a practical heating or cooling system. Since solar energy is relatively dilute when it reaches the earth, the size of a system used to convert it to heat must be relatively large. Solar energy collectors, the devices used to convert the suns radiation to heat, usually consist of a surface that efficiently absorbs radiation and converts this incident flux to heat which raises the temperature of the absorbing material. A part of this energy is then removed from the absorbing surface by means of heat transfer fluid that may either be liquid or gaseous. One of the simple forms of solar energy collectors built is the flat-plate collector (Nosa et al., 2013). Solar water heaters can operate in any climate.