The Geothermal system guarantees a high quality of the home environment, keeping it warm in winter and cool in summer. The prices are low and it is in full respect of nature. The innovation lies in the performance of the two hot-cold functions which normally concern two different types of appliances, namely boiler and air conditioner. Therefore, the geothermal system is proposed as a perfect alternative to traditional systems.
- Plant defined as “Monovalent” will be able to heat and cool an entire building without poisoning itself with other equipment.
- A Geothermal plant defined as “Bivalent” will instead be able to integrate with solar thermal systems or condensing boilers.
A monovalent geothermal system uses the heat pump to regulate the temperature of the internal environments. By definition, a heat pump is a machine that transfers heat from a colder body to a warmer body. By taking advantage of the soil temperature, which remains roughly constant, this type of system is able to guarantee high performance. This brief overview serves as an introduction to understanding the extreme importance of this exceptional power plant system.
But now let’s see in detail how this innovative technology works, still too little known and exploited here in Italy.
Table of contents
- Principles of Operation Geothermal
- Performance of Geothermal Plants
- How much does a geothermal plant cost?
- Incentives for 2021
Principles of Operation Geothermal
A geothermal plant consists of three fundamental elements:
They are polyethylene pipes that directly exploit the energy present in the subsoil and in the water present in it, managing to function as heat exchangers. The pipes are generally buried in the ground at great depths, vertically, with the name of vertical geothermal probes, or alternatively at a depth of 1.5-3 meters but horizontally (horizontal probe).
It is very important to underline how the ability to extract emotive energy is practically possible throughout the national territory, and how it is the geological and climatic characteristics that determine the best collection system and consequently the best plant option.
Geothermal heat pump
It is installed inside the house and allows the transfer of heat from the ground and water to be able to heat, or by reversing the cycle, to cool.
Heat accumulation and distribution system
The accumulation and distribution system allows, through the use of a hot water tank, to store and consequently distribute all the heat to the building. The heated water accumulates in the tank and thanks to its insulation it can keep its heat even for days.
The distribution takes place thanks to the so-called radiant panels. These are essential for the circulation of hot water in winter and cool in summer, heating and cooling. The energy consumption of the panels is very low and extremely efficient as they work at low temperatures. The radiators need 70 ° C, the radiant panels 30 ° C.
We now come to dwell and analyze in detail the performance of the geothermal plant.
Performance of Geothermal Plants
Unlike an air-to-air heat pump (split), the geothermal heat pump has an efficiency that reaches even 400/450% constant. The heat pump air conditioners we use suffer from sudden changes in temperature as they draw their source from the outside air. Once the outside air temperature falls below 2 degrees, the efficiency of the split decreases considerably. The efficiency of all heat pumps is measured in COP.
Example COP 4.5 efficiency = 450% = if it consumes 1 kw it makes 4.5 kw (an electric stove has a COP = 1
The life of the plant is around 15 years for heat pumps. Geothermal probes are able to be exploited up to an advanced age such as 70-90 years. The radiant panels can easily reach 20 years of activity. Fundamentally, the entire system does not require maintenance; this explains the very high efficiency and cost efficiency of this extraordinary technology.
Thermal energy is completely free, allowing both heating and cooling in a single system. It ensures operation for 365 days a year, reducing CO2 emissions and the emission of pollutants into the atmosphere. This does not even pollute the ground, thanks to the circulation of non-toxic liquids inside the geothermal probes. The heat pump is extremely silent, thus guaranteeing very high quality performance standards for the entire system, right down to the final process.
Video Explanation Geothermal site: L’Altra Energeia
Let’s now analyze another fundamental aspect of the geothermal plant, namely costs.
How much does a geothermal plant cost?
First of all, the costs of drilling the soil must be considered, which are around 50 euros per meter drilled, and having to calculate the drilling depth in a minimum of 50 up to 150 meters, depending on your need, you can reach an estimate that varies between 3,000 and 9,000 euros.
Furthermore, the costs are influenced by fundamental factors such as the size of the plant, as well as the hydrological and thermal differences of the subsoil. In fact, some types of subsoil are able to have a higher thermal efficiency than others; for example, a subsoil predominantly rich in sandstone rock will certainly have a higher yield than a dry subsoil.
Starting from these summaries, a first overall estimate of the costs of a geothermal pump equipped with vertical probes can be drawn up, which however varies from building to building: on average, a house of 80-100 square meters, comes to spend on the installation of both around 20 thousand euros. The price is slightly lowered if the probes are installed horizontally, but the surface necessary for carrying out the work will be greater. The installation of the radiant panels involves additional costs that are around 6-7 thousand euros.
These costs must also be considered in relation to state incentives, which for 2021 provide for important reductions: let’s see them together.
Incentives for 2021
The incentives for 2021 come in the form of the “Eco bonus 2021 Package” which provides for the reconfirmation of the 65% tax deduction for individuals and businesses aimed at encouraging energy redevelopment interventions, such as the installation of a geothermal system. The incentive rises to 75% if the interventions are made by the condominium. The incentive aims at aligning European standards on renewable and eco-sustainable energy.
To ensure the bonus it is necessary to present the necessary documentation, which will take the form of a summary sheet of the works carried out in the building, a document certifying the energy certification, the certificate from the manufacturer of the entire system aimed at certifying the required requirements by the law on the installed system, as well as the receipts of payment.