A quite big percentage of
solar radiation of about 50% which is falling on Earth is stored into the Earth's crust, being an inexhaustible renewable
energy source called “geothermy” or “geothermal energy”. The great advantage of
this thermal energy is that it has a constant
temperature throughout the year and even close to the room temperature that man
desires, either during heating or cooling.
The principle of geothermal air conditioning is based on the fact that a few meters below the surface of the earth, the temperature of the soil is stable at 18-22 °C. So, if we take advantage of the temperature difference between subsoil and surface, we can heat rooms during winter and cool them in the summer respectively. A geothermal energy system for residential applications consists of three main parts:
• Geothermal heat pump
• Geothermal heat exchanger
• Internal heating and cooling installation of the building
Such an installation exploits the stable subsoil temperatures by transferring
heat from the subsoil (or underground water) to the air conditioned space and
vice versa. This is done by using a geothermal heat pump and a piping network
placed horizontally at a low depth into the ground, or in a vertical arrangement,
exploiting a drilling that is made for this purpose. The most important fact in
a geothermal system is that it saves 50-70% of energy compared to conventional
means (oil or electricity). Geothermal heat pumps are combined with low
temperature heating and cooling systems (underfloor heating, fan coils,
ventilators, etc.) and radiators. The advantages of the geothermal system are
unlimited and we mention some of them as follows:
• Stable clean and renewable energy, independent of weather conditions
• Independence from oil and electricity which results to energy savings of up to 75% for heating and 40% for cooling
• Low maintenance and installation costs
• Silent operation, absolute safety and reliability
• Space saving once small machinery are required for the system
• Technology absolutely environmentally friendly, as it does not require combustion and does not release pollutants
• Minimum installation requirements
• Short payback period of project costs
Geothermal systems are fully
automatic, providing heating, cooling and hot water throughout the year, without
the need of daily surveilance.