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Geothermal: how it works

Geothermal: how it works


Geothermal, intuitively, geo is termia, suggests something to do with earth and heat, but how? Is it good, or rather, is it "green thing"? Advance only that regardless of outside temperatures brings us free thermal energy, except the electricity consumption of the heat pump. And this energy ensures the operation of a plant for 365 days a year. That said, a dream for a thermopath like me, better understand what lies behind this beautiful perspective.

Geothermal: meaning

The discipline of geothermal deals with natural phenomena related to the heat coming from inside the Earth. We are interested because, by studying it, very useful principles are revealed then at the technological level for electricity generation and cogeneration, with the power plants of geothermal that exploit the energy generated by means of geological sources of heat, called "geothermal".

From geothermal, so here's one alternative and renewable energy, if evaluated in a short time. What is exploited, in particular, is the natural heat of the Earth, that thermal energy released by the natural nuclear decay processes of the radioactive elements naturally contained in the core, mantle and crust of the earth. They are usually uranium, thorium and potassium.

Today thegeothermal energy it represents less than 1% of world energy production but has great potential and the scientific community believes in it. It is also often used in cogeneration situations, as well as "single" for the production of thermal energy to heat rooms or water for sanitary use.

Geothermal in Italy

The first energy generator "inspired" by the geothermal in Italy was "born on July 4th". Yes, from 1904, in Larderello, in Tuscany. In general, geothermal systems in the residential area are not very widespread and well-known in Italy, there is no comparison with Northern Europe and the United States. There was an acceleration, however, with theintroduction of targeted incentives: numerous new geothermal plants with heat pumps have sprung up on the peninsula.

Today the tax deduction continues, with a deductible portion of 65% which has been extended from year to year, for the last time since Stability Law 2016, until 31 December 2016: we can well hope that the acceleration will continue. As an alternative to tax deductions, the fact remains that geothermal plants and heat pumps can access the Thermal account.

Alla geothermal our country is very popular, so much so that in general the resources linked to it are available throughout the territory. If we are thinking about geothermal energy and its 365 days a year of comfort - I do - it is important to know the characteristics of the subsoil, below us. For example, the type of soil, the possible presence of groundwater or hydrogeological constraints. With the help of specialized operators it is easy to determine the technical feasibility of a plant for geothermal, there are also ad hoc geological investigations to accurately assess the quality of the geothermal resource.

Domestic geothermal

There geothermal knocks on our houses offering to produce hot water for winter heating and for sanitary purposes and cold water to cool, in summer, with the advantage of being able to install a only system that acts as a boiler and air conditioner.

This device that uses the geothermal for us, it is “monovalent” if, appropriately sized, it manages to heat and cool a building by itself. Otherwise, we don't throw in the towel, and neither geothermal: the geothermal system can be integrated with other high-efficiency heat generators, it is frequently combined with solar thermal systems or with condensing boilers.

For new buildings, under construction or to be built, the geothermal is perfect, so we can design the system from scratch in an optimal way, for the existing ones, however, it must be said that it is better to evaluate the convenience and feasibility, starting from the availability of physical space for setting up the site and for laying of the geothermal probes.In general, the choice of geothermal it remains advantageous even for existing buildings if they currently have expensive and polluting fossil fuel boilers while in the case of natural gas boilers, it depends. In all this, let's not forget to check, and improve, thethermal insulation of the building, especially if it's not new.

Geothermal probes

The geothermal probes are one of the 3 fundamental elements of a geothermal system, followed by the geothermal heat pump and the heat storage and distribution system. The geothermal probes are a heat capture system and in practice we can imagine them as polyethylene pipes that act as heat exchangers, exploiting the thermal energy present underground or in the water. Completely non-toxic anti-freeze refrigeration liquids flow through them which ensure that the energy gives geothermal can be considered alternative and "green".

When they are buried vertically at great depths we speak of vertical geothermal probes, they become horizontal, also called collectors, when they penetrate the ground at a depth of 1-2 meters horizontally. When we decide to move from the ground to water, as a source of heat, we always have geothermal probes and always vertical.

To choose, from time to time, the geological and climatic characteristics of the place where we want to sign our friendship with geothermal. We quickly complete our visit to the plant: the heat pump is inside the buildings and is the heart of everything because it transfers the heat from the ground or water to the internal environment. In summer it cools, so it has to reverse the cycle.

For the accumulation and distribution of heat, i fan coils or i radiant panels, the latter are the best system solution: in winter they give us hot water at 30-35 ° C, in summer cold at 18-20 ° C. When I talked about the maximum degree of comfort and energy savings, da geothermal, I wasn't kidding! In the geothermal plant there is also a storage tank for hot water, essential for storing heat and then distributing it to the building but also in the case of cogeneration, when it is necessary to integrate geothermal practices with solar thermal systems or condensing boilers.

Geothermal: costs

Among the various advantages of a system that exploits the geothermalmany relate to costs. The operating ones, for example, are about 60% lower than a heating system with a natural gas boiler. Furthermore, by installing only one system for summer and winter, you also save on costs of the air conditioner.

Not in euros, not directly, but a nice saving for the Earth and for humanity is that in emissions: the geothermal energy reduces those of pollutants and CO2 in the atmosphere compared to other less green practices. If we talk about greens, these plants do not pollute the land and do not even produce noise pollution as they are as quiet as a new generation refrigerator.

Returning to geothermal and portfolio, a plant almost never requires maintenance in life. We take into account that its average life depends on that of the individual components: geothermal heat pumps last 10-15 years, geothermal probes many tens of years, radiant panels 20-30.

Geothermal: how it works on video

There geothermal and its mysteries are revealed and captured in an excellent video that, if you chew a little English, instructs and amazes. Personal opinion: the drawings help a lot, so you can guess even if you are not a British native speaker. Good vision.

Geothermal: opinions and studies of those who are not in favor

With the development and diffusion, even if not strong, of plants based on the geothermal Committees and associations have also arisen which believe that the axiom geothermal energy / clean and renewable energy is false. It is not a question of political or principled positions but of people who, in most cases, experience the application of geothermal on the territory in which they live and can provide opinions and points of view, stories and information that help to have a complete picture of this type of energy.

Who is not in favor of geothermal points out that it, depending on the composition of the subsoil, cannot be the panacea for all ills everywhere and in any case. An example supporting this position is Mount Amiata in Tuscany where it is neither clean, nor harmless to health, nor renewable. There are studies and material that show that in this case, but it would not be the only one in Italy, the emissions are comparable, as climate-altering, to those of fossil fuel plants. Furthermore, the wells themselves would soon become unproductive. Or economically unprofitable, which would belie the fact that the geothermal can provide renewable energy.

A study by the Tuscany Region itself relating toenvironmental and epidemiological impact of geothermal energy, to highlight an increase in pathologies and deaths always in the exemplary case of Mount Amiata.

For those who want to learn more about the position mentioned above, I recommend the site of "SOS Geothermal - Coordination of movements for the Amiata”In which it is possible to find abundant and precise material to support the thesis of those who are not in favor of Geothermal.

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Video: Geothermal Greenhouse: It worked. It REALLY Worked! (July 2021).