Utilization of Solar Energy – Part 2

The ever increasing use of fossil fuels is currently threatening our very existence by polluting air and water, and bringing about catastrophic global warming. Now is the time to take advantage of solar energy as an abundant resource of non-polluting alternative source of energy. Solar energy is received through radiations covering a very wide spectrum of frequencies – from infrared through the visible to ultraviolet frequencies. Radiations in Infrared and Ultraviolet range cannot be seen, only visible range of radiations is seen.

There are two major application areas in which solar energy can be used as inexhaustible alternative source of energy: for heating, and for generation of photovoltaic electricity.

Solar energy for heating

The infrared radiation causes heating effect. For ages men have been utilizing solar energy for heating. Even in the medieval ages techniques had been developed to design houses in a manner to use the solar energy to keep houses warm in winter and provide cooling draughts of air to cool and ventilate houses in summer. For a long time various methods have been used to provide hot water for domestic use and for comfort heating of homes by using solar energy; solar cookers also have been used for cooking food. There was a time when vehicles driven by steam engines running on solar energy were being tried out.

In the recent years many developments have taken place; now solar energy is used not only to provide domestic hot water supply or space heating of large buildings but it is being used to provide hot water, steam, etc for industrial processes and even to supplement power generation in large thermal power stations.

Solar energy for electricity

Generating electricity by photovoltaic conversion is a relatively modern development. “Photo” in Greek means light and “Volt” relates to scientist Alessandro Volta, who invented electric battery and contributed greatly to the study of electricity. The term Photo-Voltaic, thus, refers to light-electricity or electricity from light. A PV (photovoltaic) cell is a device made of Silicon – a metal - processed in such a manner that it will exhibit strong photovoltaic properties converting visible solar radiation into electricity.

Small PV cells have been in use for long in low power applications such as calculators, watches, etc. Individual PV cells or solar cells are small and give very small amount of power. Now PV cells are assembled in various configurations as panels and arrays so that sufficient electricity can be generated by using them for practical purposes.

Recent developments have made it possible to use photovoltaic cells to provide clean power to remote and inaccessible communities, to run cars on solar power, to supply power on satellites and space stations and even to supplement power generation in large power stations of hundreds of MW.

Using solar energy as alternative source of energy in various applications can help us in cutting down pollution of our environment and contribute towards the efforts to check global warming.