Geothermal energy, what it is and how to use it
Among the many forms of renewable energy that we can exploit from the planet Earth, we can use geothermal energy that is the energy that can be extracted from the ground in the form of heat.
In housing this energy from subsoil is exchanged with the ground and can be used both in air and in space heating of our homes .
This energy produced by our planet derives from a series of nuclear reactions in the core of the Earth , these involve an increase in temperature , which then transmits on the crust until arriving at the surface.
The soil accumulates the heat coming from the core, in the first few meters of depth from the earth's crust , the soil temperature is close to that of air, whereas if we go beyond 15 m underground the temperature remains more or less constant .
How to use this energy
The current systems for heating and cooling using geothermal heat pumps are based on the principle that the ground temperature , is indicatively maintained almost constant during the course of the year.
This aspect involves benefits both during the winter season , because the ground in this period has a temperature a little warmer than the outdoor air , both during the summer season because the temperature is lower than that of air . The pumps adopt a system of underground pipes connected to the exchangers, which use the flow of liquid to add or remove heat in various environments.
The heat exchanger and the reservoir of the water should be placed underground. Whereas, the heat pump should be placed in places such as the basement, the garage , in dressing room but it can also be placed out to a balcony, the most important thing is that it has to be protected.
Types of geothermal systems
We can speak of two types of geothermal energy : geothermal depth , which is the range that varies from 100 to 5000 mt. This exploits the heat of the subsoil at great depths , through the appropriate turbines the vapors produced from the sources of water present in the soil are collected with the aim of producing electricity . Always from the hot springs located at great depths can also take advantage of the heat produced by the steam district heating for local activities .
Then we have the geothermal Surface,which covers the range from 3-100 mt, and this one is used for environmental air conditioning heating and cooling , again through the use of electric heat pumps and absorption .
As the depth on which it operates are lower we have two possible ways to capture the geothermal source .
We may use geothermal probes both vertical and horizontal in which the heat transfer fluid flows , these are also known as closed circuit . It may also use plants that exploit the ground water as heat transfer fluid , this water can be pumped back into the aquifer or less after its use , this type of circuit is also called open circuit .
They are called geothermal reservoirs , ponds precisely those used for the production of geothermal energy. These are inexhaustible because their existence depends on the earth's core , the temperatures reached in these basins are higher than 150 ° C at variable depths .
How is a geothermal plant , pros and cons
A geothermal system has several components, including a system for the collection, treatment and conveyance of geothermal fluid , which goes from the source up to the production of electricity and a system of electric energy production , consisting of a turbine - generator , a transformer and then related connections to the electricity network ; from a treatment system of the exhausted steam , consisting of a condenser with attached pump extraction of steam condensate ; from a geothermal reinjection water system in the basin .
The geothermal source also during the course of the year brings a constant supply of energy, its main use is the production of electricity, but depending on the temperature of geothermal fluids, it can also be used to supply spas, swimming pools, radiant panels and plates , heat pumps , home heating . The important thing is to learn to make a proper use .
Compared to a normal plant , a geothermal system allows us to save up to 80 % of the cost on our bill . In addition to the economic benefits, geothermal energy offers many advantages , including the noise of the system, moreover there is no danger of fire and gaseous emissions because it does not use any combustible substance , and finally is an ecological system .
But this type of system that uses geothermal energy has gpt disadvantages too , such as the typical smell of the thermal zones , much like that of rotten eggs. This smell is caused by the steam coming out from underground, which essentially consists of hydrogen sulphide. To solve this problem you should install abatement systems .
The other negative aspect it is about the aesthetics of this plant that looks like a tangle of pipes , sometimes of considerable size, depending on the size of the geothermal plant . Their presence in gardens could be really unpleasant from an aesthetic point of view .
Articolo dell'Ing. Gilda Montesano
Fonte foto: http://alemainvest.com/