An energy crisis? Soil, a battery to heat and cool our homes.

The exchange of heat with the ground for heating/cooling rooms is possible in almost every national territory, this source of energy is unknown but invaluable. Furthermore, if the heat is high, it can turn into electricity even in your garden, with the innovative system developed by GeoGrid project researchers.

Content created within the CNR 4 Elements project

Figure 1. Earth’s natural heat: Evidence of hot fumes escaping from the Earth.
(Photo by Solfatara di Pozzuoli by Donar Reiskoffer, CC BY-SA 3.0,

From Marina Yorio

The energy crisis and the consequent rise in bills is a concern that affects everyone. Our life today depends entirely on electrical and thermal energy, for example we think about the importance of a mobile phone, a computer or the need to heat our homes. We depend on processes that we cannot manage and are powerless in the face of any severe blackout.

However, alternatives exist and are within everyone’s reach. Let’s see why: Earth’s heat (Fig. 1) is a renewable energy source that springs from the warm heart of our planet. This form of energy, unknown today, is widely available throughout the national territory. Groundwater or soil heat, up to a few tens of degrees, can be taken through heat exchangers. A heat exchanger is a system used to transfer heat energy from a fluid at a higher temperature to a fluid at a lower temperature. This exchange can occur either by mixing the two fluid streams, as in the case of a faucet in a home, or by keeping the two fluids separate as in a car radiator or in a household radiator.

In the case of heat exchange with the Earth (Geoscambio), heat exchangers consist of batteries of tubes in which water circulates, which are inserted underground to take heat energy from the ground and deliver it to civilian users such as a home or a school. , from the industrialists. If the heat from the ground is insufficient, a heat pump is added, a machine capable of transferring heat energy between two sources using electrical energy. The lower the temperature difference between the floor and the house, the less electricity is used and the greater the savings. So in winter the heat can be taken from groundwater or from the ground and transferred to the house to heat it, but in summer the opposite happens, that is, the heat is taken from the air inside the house, cooled and transferred. to the field of underground investigation. This form of energy is spread throughout the national territory and has invaluable value because it can promote economic development in various sectors of production, in fact, the need for conditioning environments or heating healthy water belongs to many industries in the agro-food sector and manufacturing. Among the many possible examples, we mention the need to adapt greenhouses and cellars to produce vegetables and preserve wine. Finally, we know that if Italy replaced all traditional fossil-fueled air conditioning and hot water production systems, with heat pumps and geo-exchange systems, we could save up to 3 million tons of oil equivalent each year.

The advantage of using the heat of the earth, which ranges from a few tens to tens of degrees, can be used to condition rooms, but also to produce electricity, as we said earlier, does not end with its use as fossil sources. However, since the amount of heat on Earth varies from place to place, it is important, in order to use it, to know the maximum amount of heat or water that can be obtained from the soil and groundwater in a given area without cooling it. . To calculate this quantity, an “assessment of the geothermal potential of the soil” is carried out, that is, through chemical and physical analyzes of the groundwater and geophysical analyses, a type of radiography of the subsoil, and a virtual 3D model of the reconstructed subsoil, of circulating water and temperatures, what It is called the “geothermal model”. In this context, scientists are asked to try to develop increasingly sophisticated and complex technologies to make the most of the Earth’s heat, without affecting the environment even visually, as happens for example with wind turbines to produce electricity.

Recently, the National Research Council’s Institute of Marine Sciences, as part of the GeoGrid project, with funding from POR FESR Campania 2014-2020, in collaboration with university partners, the National Institute of Geophysics and Volcanology and companies in the sector has strongly committed to improving the ability to “envision” the underground world Invisible to the human eye. As Maurizio Milano, a researcher at the Institute, explains, “We have worked to develop methods for the joint analysis of geophysical data, for example the speed of sound and electric waves that we enter into the Earth’s interior to study, so that the ‘radiography’ of the Earth’s interior, which we build from the processing of this data, is done. becoming increasingly clear and detailed. However, the work went further, and a sophisticated software “Geogrid Viewer” was developed to be able to see these X-rays in focus, along with other data collected both physical and chemical (for example temperatures, content of salt dissolved in groundwater) all to give us a hypothetical but very honest view of the Earth’s interior, for example precise locations of where hot fluids rise from the depths and how much heat they hold (Fig. 2).

Figure 2. Hypothetical representation of the subsoil in the Agnano Basin, Campi Flegrei volcanic zone, by ‘Geogrid viewer’.

The acquisition of this knowledge was a prerequisite for the work of the project partners, in coordination with the University of Naples “Parthenope”, in particular to develop a prototype of a plant for the production of electrical and thermal energy, as large as a small container and therefore easily installed in a garden or courtyard, or to develop a system that constantly monitors and improves The energy performance of geo-exchange systems, we mention, is useful for heating and/or cooling our homes. The products of the GeoGrid project will be presented to the public by the Campania region at the Expo 2020 in Dubai, with the docufilm film, “The Grand Tour of the 21st Century. Naples between art and technology » Snapshot in collaboration with CNR WebTv.

From Marina YorioAnd the CNR-ISMARPresident of CNR GeoGrid

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