Technologies for geothermal energy use
Types of technologies
Geothermal energy is a method of deriving heat available from the earth's core. Its extraction on the surface of earth can be achieved through thermal waters, through volcanoes, or by forcing water through heated rock massifs. The resources of geothermal water can be classified according to their temperature and application area, as follows:
Low potential resources of geothermal water (with temperature from 10 to 10 0° ) are used for heating , greenhouse production, industrial processes, and for balneotherapy treatment procedures. Energy using earth connected thermo pumps that use subsoil waters near the surface can be referred to as geothermal energy.
Earth connected thermo pump installations do not generate heat. Due to the opposite of the refrigerating process, the thermo pump, is set in motion by an electric generator which derives subsoil heat (or the heat of subsoil water or heat in a reservoir) with a lower temperature level and takes it to another level radiating it with a comparatively higher temperature level. The costs of the energy required for setting in motion of the pump, which will “remove” the underground (water) heat. Average electric energy cost for the pumps compared to the useful heat produced is 1 to 4, which means, that if the consumed power is 1 kW, the heating power is 4 kW.
If the temperature of the subsoil water is 12 ° and after it has passed through thermo pump device, it is injected back in the soil with a temperature of 2 degrees C, then every single cubic meter water that has passed through the system will release about 12 KW of useful energy. If a pump, that has a capacity of 10 liters per a second works for just 10 minutes, it will pump up 6 cubic meters of water, which means that about 46 KW of heat energy will be transported, which is equal to a heat generator, (electric boiler for example) with a power of 270 kW, and the electric power, required for installation operation will be less than 70 kW. In this example for one hour up to 70 kW of electricity will be consumed and about 270 kW heat energy will be produced.
The process described in this example uses the so called, thermo pump system ”water-water”. It is one of the most economic machines for heating (particularly for air conditioning during the summer). This system is even more efficient, when electricity that is required for the pumps is produced through PHV or through a wind turbine.
Geothermal water with “average temperature”- here are classified subsoil deposits under pressure with a temperature 90 ° - 180 °. They can be used for electricity production through a direct release of steam which makes the turbine move or if the temperature is below 140 degrees C the so called bivalent system with secondary organic fluid is used.
Geothermal water with ”high temperature” – In this case saturated or dry steam deposits are used, with a temperature between 200 ° to 350 ° for electric energy production.
Can I use geothermal energy in my enterprise?
The technology earth connected thermo pump installation is applicable everywhere. Utilization of the other geothermal sources is not an individual project for a company. It can be achieved only in collaboration with local authorities. So before you start such a project, answer the following questions:
1. Are there geothermal resources available in the region of company - steam or water with “high temperature” or “average temperature”?
2. Are there opportunities for funding the project by local or international sources?
3. Is there a regional strategy for developing of RES?
If your answers are positive, then the construction of geothermal electric systems will be technically, financially, and naturally viable