Geothermal energy

Geothermal energy is related to the heat of Earth’s core. It usually manifests as earthquakes, volcanic activity or geysers andhot springs. The proof of vast volcanic activity in the area of Slovakia is abundance of hot springs and bores which are mostly used in the spa industry or tourism. Only because of the energy of Earth can we bathe in various aquaparks throughout the year. Geothermal energy can be used for heating – in Galanta there are more than a thousand apartments and a hostpital getting heat from this source. In Podhájska the greenhouses are heated by geothermal energy. There has been talk for many years about the possibility to supply heat from bores to whole city of Košice. Hot water from such bore has to transfer it’s heat in the heat exchanger to a liquid that flows in the heating bodies. Disadvantages of geothermal energy are high investments in bore preparation and also the fact that there are supposed to be two bores – through one the water is pumped up, through the second it goes back. If we would not do it this way we would endanger the quality of surface water with abundance of minerals coming from water obtained from the bore and with draining of water we could  endanger the bore itself. High level of mineralization of these bores presents us with high demands on materials used in the heat exchanger. Corosive environment of geothermal bores in low-quality materials quickly takes its toll . In the world (USA,New Zealand,Italy) geothermal energy is used also for electricity production. There the temperature of water steam exceeds 200°C whether in Slovakia the temperature is between 45 to 130°C.

Heat pumps

Heat pumps represent a subset of heat energy utilization possibilities. The principle of their working resembles the opposite of the fridge. That means the earth (either in deep bores – wells or wide horizontal fields of collectors approximatelly one meter under the ground) is slightly cooled – we take the heat from it and deliver it to the building or housing settlement. Heat pumps are not a clean renewable energy source, but they are considered a part of energy efficiency measures.