Geothermal energy, as a Renewable Energy Source (RES), especially when combined with other RES technologies such as photovoltaic systems, can transform a building into a ZEB (Zero Energy Building).
This is because geothermal systems, with just 1 kW of electricity input, can deliver 4 kW of heating and cooling output, thus giving the system the characteristics of a renewable energy source with stable performance and an efficiency of 400%.
A shallow geothermal system takes advantage of the thermal influence of the ground. Put simply, at just 1.5 meters below the Earth’s surface, the subsoil has the ability to maintain a stable temperature, unaffected by the climatic conditions prevailing at the surface. This temperature is called the undisturbed ground temperature and is a characteristic of each region (for example, in Crete this temperature ranges from 17–21°C). Therefore, by applying geothermal energy for the heating and cooling of our building, we stop interacting with fluctuations in outdoor air temperature, as happens with an air-source heat pump, and instead benefit from the warmth of the subsoil during winter and its coolness during summer.
The ground is a fundamental element of bioclimatic architecture. For this reason, geothermal energy is an ideal choice for the bioclimatic design of a residence, since it takes advantage of the stable temperature of the subsoil. It is worth noting that one of the main advantages of geothermal energy is that it does not alter the aesthetics of the building, as it does not require exposed equipment such as air-source heat pumps. In this way, geothermal energy contributes to the full harmonization of the building with its environment.
In terms of environmental impact, geothermal energy has been recognized as the most environmentally friendly method for heating and cooling buildings.
Other categories of buildings for which the use of geothermal energy is recommended include the following:
– Sustainable House
– Passive House
