Source renewable solar energy for your water heaters

Humans have harnessed solar heat and light from the sun. This energy along with others obtained from wind and wave, water and biomass have been sources of the most renewable energy on earth. Actually only a small fraction of the solar energy has been utilized; limited by human innovation and ingenuity. Solar panels are the commonest way to harness solar energy and these can be used for solar water heating. These heating systems have witnessed several innovations and are being widely used in countries e.g. Turkey, Israel, Australia, Greece, Japan, and Austria. Solar technology is broadly divided into two categories – passive solar and active solar which is dependent on the way the solar energy is captured, converted and distributed.

When water is heated by the sun it can be used in numerous ways, with the best use being to provide domestic hot water and solar water that can also be used in industries. Designs of solar water heaters for hot climates are different from those in cold climates and the solar water market is dominated by countries in Europe, Japan, China and India.

Solar water heaters are of two categories:

A close coupled system that has the storage tank mounted horizontally just above the solar collectors on the roof of the house. There is no requirement for a pump because the water rises automatically through the thermo siphon flow.

The pump circulated system where the storage tank is mounted on the ground or on the floor and is situated below the collectors. In this, a pump circulates the water through the tank and heat is transferred between the tank and solar heat collectors. In colder climes, the pipes may have anti freeze to prevent them from freezing.

Both these solar water heaters are designed in such a way that they are able to deliver hot water throughout the year. An auxiliary energy source (electric heating element or the connection to a gas central heating system) is activated when the temperature in the water tank falls below 55 degrees Centigrade and water starts getting heated up again. However, during winters when the need for hot water is the maximum, these solar heaters may not be able to fulfill the need. In these cases, an electric system using gas is used to heat water.

Home solar power can also be used to cook and generate electricity. Products can include solar lanterns, solar home lighting systems with or without LED, solar cookers etc. Solar lanterns have been a great boon to people in remote areas where it has been difficult for governments to provide electricity. In these areas, with the availability of solar heat and light generating technologies, people have electricity in their homes and can also use solar cookers to cook their meals. This ensures that the dependency on non-renewable energy sources is reduced.