Using conventional sources of heating has many drawbacks. The electrical energy required is produced by burning fossil fuels and by doing so, the air gets polluted with smoke. Also, the energy prices are rising quite rapidly which makes it a costly affair. The most appropriate alternative to these problems is to use the geothermal energy for heating purpose. Of course, this energy cannot be harnessed everywhere. It is used only at places where the surface below the earth has sufficiently higher temperature. It is a very cost efficient heating system as no form of heating equipment if required. Only installation charges are present. These are also long term heating systems and can be used for years together. These systems are finding use in homes, schools and offices. The surface under the earth is heated due to the presence of extremely hot molten material way down in the earth’s interior. The extremely large amount of heat is transferred to above lying layers through conduction and this heat is captured to heat up the air or fluid which is then used for heating purposes. There are two ways to use this heat.
• Dry steam emerging from the earth’s surface is used to heat the working fluid and this heat is transferred through a heat exchanger. The heated fluid is then transported through a network of pipes. The dry steam which has now lost its heat is sent back to the earth where it is heated up again and then used to heat up more fluid.
• Instead of the steam, water is used to heat the fluid. Instead of a heat exchanger, there is an alternate medium which is first heated by the water and then its heat transferred to the working fluid. The rest of the working is same as that of dry steam system.
Geothermal Heating Systems are very efficient in electricity usage. They use nearly half of the electricity that is used by conventional heating systems. The ground source heat pumps are much more efficient in energy saving than electric heaters. This is because they fully utilize the thermodynamic advantage of the heated fluid. Hence they can produce more heat energy by using the same amount of input electrical energy. Another advantage of these heat pumps is that during summers, they can reverse their operating mode and can perform cooling action. Also, the heat energy produced by the heat pump can be transferred to a water tank. Because of this, the occupants of a building can receive hot water in winters at very low cost and free of cost during summers. These pumps can operate 90% of the time, which makes them highly reliable in the long run. Since they have to be installed at the geothermal site, the transportation and storage charges are minimized. They don’t have any rotating parts as well, which causes no wear and tear of the equipment and ensures non stop operation. It is a noiseless and pollution free system which produces sufficient amount of heat. Thus the Geothermal heating systems are finding a lot of use in sites which have heat present under the earth.
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