The sun is the most powerful source of energy in our Solar System. India is fortunate to be blessed with a sunny weather for a major part of the year. Solar energy is not only renewable, but also clean and free. So, if properly utilised, solar energy could be the panacea for all our power woes. One way to do this is through solar water heating systems, as they are economical, easy to install and convenient to use.
A solar water heater utilises solar energy to heat water for daily use. It is usually installed on the terrace or in an open space where it can get uninterrupted sunlight during the day. Heated water is stored in an insulated tank for consumption whenever required. Solar water heaters do not use electricity, which results in lower power consumption in a residence.
Solar water heating systems have two major components: collectors and storage. In solar water heaters, the collectors capture and retain the heat from the sun and transfer it to a liquid, which is usually water. It works on the principle of greenhouse effect, to trap the heat. The water which absorbs the trapped heat is transferred to a storage tank from where it can be employed for domestic use. The aim of the collectors is to absorb maximum heat and radiate as little it as possible back to the atmosphere. The coating of theabsorber and the glass is especially made to achieve this. The heated water will lose heat to the environment, which is reduced by using thermal insulation.