As you may be perhaps aware Geothermal Energy is the Heat Energy stored in the crust of the Earth. This may be in the form of Rock or Fluid (eg. Water, Steam and Water with large quantities of dissolved solids etc.) which occupy the pores, crevices, fractures and faults in the deep rocks, gravel and sand. Geothermal Energy is a vast resource of ready to tap energy under the surface of our habitat.
What is the origin of this vast source of energy?
It is believed that the source of stored thermal energy under us is due to Radioactive decay and is almost inexhaustible for the duration of the life of the planet.
Due to plate movement and volcanic activity vast amounts of this energy is brought near the surface. Also the transfer of this Thermal Energy to the surface takes place due to conduction and convection currents occurring in existing under ground water sources.
Is it available in every location on Earth?
The earth’s crust exhibit an increase in temperature as the depth increases. Under normal circumstances this is about 24 0C for every km depth. Under certain other conditions which one may call abnormal, this can vary from 9 0C to 48 0C.While locations where the so called normal temperature gradient is present this may be a valuable source of energy (under certain geological formations). The best out put is obtained from locations where one finds abnormal and extreme temperature gradients.
How is Geothermal Energy Classified?
According to the available temperatures the geothermal energy resources are generally classified as;
• High Temperature – where the temperature of the Fluid (eg Water, Steam etc.) is in excess of 150 0C
• Intermediate Temperature-where the temperature is greater than 90 0C but not as High as 150 0C
• Low Temperature –where the temperature is less than 90 0C
It is this low temperature Fluid (available almost universally) that will help you to trim your monthly energy bills up to approximately 60 -70%!
How would one tap and harness Geothermal Energy, say for example for domestic heating and service hot water supply?
The system to be used would a Heat Pump. A heat pump is a device which extracts heat energy from one substance and transfers it to a different portion of the same substance or to another different substance, at a higher temperature (for beneficial use).
The Heat Pump systems utilizing geothermal energy may be primarily of two types namely Direct and Indirect applications .They can also be Closed or Open Loop type.
While the above may be used for Community or Industrial applications, for individual dwellings these may be adopted if the hot fluids or Gas and Liquid mixtures are available due to naturally occurring phenomenon at surface level (for example hot water wells, hot water springs, fountains and geysers). The initial investment may be high where deep wells have to be drilled and high head borehole pumps need be installed.
Heat Pumps are SEI approved energy saving and sustainable devices which help the country and the community to be less dependent on imported fossil fuels while minimizing the Green House gas emissions. The almost free energy also will help the public (and the country) to tide over the current economic quagmire.
Thanks the Techstore Team