Solar water heating

Abstract

Energy And Population Growth. Accelerating population growth has inevitably put the earth's finite resources under pressure. Demographers estimated that human population reached one billion early in the 19th century; by 1930 the figure reached two billion and by 1975 the population has doubled again. At the end of last century the figure was estimated to have reached six billion. The Global Challenge. Almost all forms of energy are derived from the sun. However fossil fuels, which are the most common form of energy carrier, have received their solar energy million of years ago and have changed their characteristics so that they are now in a highly concentrated form. But the growing realization of the problems facing mankind is that there is a finite amount of oil in the ground and the present rate of use of fossil fuels (oil, gas, coal) is very much faster than their rate of formation, which is measured on geological timescales of million of years. In 1973 the dramatic increase in price altered the energy situation and thus, this crisis has lead to cutting down on energy consumption and to a search for clean, renewable energy sources such as hydroelectricity, solar power, wind power and water power which are all possible alternatives to fossil fuels.