From an energetic point of view, the process underlying the heat pump it is convenient because 1 kWh of electricity produces up to 5 kWh of thermal energy; the energy that is obtained is therefore higher than that which is used. The fact remains that installing a heat pump it is not very simple and involves a series of aspects that require a case-by-case evaluation.
The high efficiency heat pumps (as well as the geothermal systems low enthalpy, as well as water heaters a heat pump for the production of domestic hot water) risked being excluded from the 65% tax bonus for the energy requalification of buildings, with the justification that they are already supported by the Thermal Energy Account.
The Thermal Energy Account, however, as APER and Assoelettrica argue, does not offer the same advantages as the bonus and the exclusion on the whole would have penalized the solution of the heat pump compared to other choices, perhaps less efficient. Things changed during the parliamentary approval of the Decree and heat pumps were admitted to the bonus.
What is a heat pump
A heat pump it is a machine that produces thermal energy using external sources, such as air, water or soil. The energy produced can be used to heat, cool and to produce hot water. We talk about geothermal system, the most popular among the applications of heat pump, when the heat exchange source is the ground.
How a geothermal system works
At 80-100 meters underground, the temperature of the soil is constant at about 14 ° C and this allows heat to be extracted in the winter and released in the summer. The transmission medium is the circuit where the fluid passes, which absorbs energy from a first exchanger and transfers it to a second, after being passed by the (electric) compressor which adds further energy. By reversing the direction of the exchangers cycle, it is possible to operate both in heating and cooling.
Advantages. The first advantage is undoubtedly the energy efficiency, which as mentioned is high. This makes the geothermal heat pump economically convenient even in the face of a higher cost of gas compared to electricity. The economic benefits of heat pump the more expensive and energy-intensive the plants to replace are the greater (those using fossil fuels such as diesel and LPG for example).
A geothermal system well designed and installed in the correct conditions, it saves on the bill about 40% of the total cost for energy consumption (provided that the system is equipped with a separate meter). The combination of heat pump to a radiant heating and cooling system guarantees energy savings of 40% to 70% compared to traditional systems. From the environmental point of view, however, the pump of heat with heating function, it increases the use of renewable energy and in this way reduces climate-altering emissions.
Disadvantages. The disadvantages of the geothermal heat pump they depend above all on the low temperature of the water produced (high temperature systems are also possible, but the higher the degrees, the lower the convenience) and the increases in electrical power. The system noise can also be a problem and the machine must preferably be outdoors. The installation of a geothermal heat pump it requires installation work which can be expensive.
Conclusions. The installation of a heat pump usually it is convenient (the advantages outweigh the disadvantages) and it is certainly an 'eco' choice, but it must depend on an in-depth technical assessment of all the aspects involved: plant potential, combinations with other technologies, installation of a second meter which allows you to take advantage of a dedicated electricity tariff (based on Resolution no. 56/2010 of the Energy Authority of April 2010) because otherwise the surplus in electricity consumption becomes penalizing.
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