Geothermy


Geothermal energy is the stored under the ground in the form of heat.
Geothermy is based on the fact that the subsoil temperature is kept constant throughout the year without being influenced by external conditions.
Geothermal energy is a renewable and inexhaustible energy source which is offered for free by nature and is environmentally friendly. By taking advantage of the constant temperature (that the subsoil offers) and independently of the season, we can cover the heating needs of a building in winter and the cooling needs in summer as well as the water supply by using geothermal heat pumps and pipe network within the underground.
Geothermy reduces the operating costs of heating and cooling and works best with underfloor heating because in that way we have the ability to use as additional auxiliary power source the sun.

The categories of geothermal systems are:


A) Open geothermal system


It is applied to areas rich in aquifers or springs (either groundwater or at the surface on earth). The water taken from the aquifer passes through the geothermal heat pump where it gives the required energy and returns to the source. Although the installation of this system is the most economical and has minimal land surface requirements, it needs often maintenance which depends on the quality of the water.


B) Closed horizontal geothermal system


The horizontal ground heat exchanger is put in at least 1.5 m below the ground level. The pipe layers can be installed at many levels with the presupposition that they have 1 m vertical distance between them.


The pipes must be installed in a specific distance between them. The required surface of the pipe installation is calculated according to thermal and cooling requirements of the building. The output of the geothermal heat exchanger is 25-30 w/m². Restrictions may be due to the geological characteristics of the subsoil (e.g. if it is particularly rocky). This system has the most economical installation (among the two closed geothermal systems) and with the presupposition that the space of the area is sufficient, it is used more often than the closed vertical.


C) Closed vertical geothermal system


When the space of the area is not enough for horizontal geothermal exchanger or the composition of the subsoil is not suitable for the horizontal system, the vertical geothermal

exchanger is applied. Each bore has a depth of 70-100 m. In order to avoid the thermal saturation of the subsoil, the distance between these bores must at least 5 m. The number of the bores depends on the required capacity of the system. Each vertical geothermal exchanger has an average output of 40-45 w/m. Depending on the working pressure, the pipes used in this system are AQUAFLEX (PE80 or PE100).