Utilization of geothermal energy
The geothermal energy means the inner heat reserves of the Earth supplied by the decay heat of the radioactive isotopes of long half-life (uranium, thorium and potassium). Since these elements are concentrated in the crust, the most of the heat can be utilized from the technically recoverable depth range of 0-6 km.
The heat of the Earth means inexhaustible energy source for the geothermal heat pumps and is available independently of the seasons.
A sufficient quantity of stored energy is available under every building, even more than is necessary to meet heating and cooling demands. We simply must extract this energy. The geothermal heat pumps serve for this purpose.
The geothermal energy is available on various temperature levels and the different temperatures can be utilized in different ways. The figure below shows these ways of utilization:
Geothermal heat can be utilized even under 30°C directly by heat pumps (vertical geothermal heat exchangers, horizontal ground loops, and closed loops in natural water, such as lakes and rivers, groundwater or deep groundwater wells). The heat pump increases the heat level of the primary side on the secondary side up to even 60-65 °C for the heating and domestic hot water supply.
Figure: Direct geothermal energy utilization in the world: (a) whole built-in capacity, (b) whole energy consumption
The thermal waters of medium temperature (30-100 °C) are mainly used in the agriculture and for space heating, but its heat is also utilized in the food industry.
Thermal waters and vapors of high temperature (above 150 °C) can be used for even electricity production. Power plants are supplied with hot water by deep drilled thermal wells and only they can be used for energetic and cascade purposes. In cascade use the waste water of the systems of higher temperature is utilized in the systems of lower temperature (agriculture, bathes and swimming pools and heat pumps) in order to increase the efficiency of utilizing heat energy. These complex methods of utilization resulted in the popularization of the heat pump systems (six fold increase over the past ten years) all over the world.
In Hungary, following the official licensing process and legal regulations in 2002, the quantity of heat produced by heat pumps exceeded, as estimated, 5 MW at the end of 2005. Our company played key role in the above mentioned licensing and professional preparation procedures and is still the acknowledged professional partner of the authorities. Our efforts resulted in creating the conditions for the intensive utilization and increase of the geothermal energy like in other EU countries; and the positive results of the year 2009 confirm this fact: the heat capacity built in by our company has reached 5 MW (150,000 meters bore holes), and it is expected to reach 10 MW (200,000 meters bore holes) until the end of 2010.