In the home environment, the energy used for space heating represents the greatest electricity consumption. The energy used for heating uses fossil sources, which are expensive and harmful to the environment. Aheat pumpit can heat the house with excellent yields and, thanks to its ability to function as an air conditioner, it is an excellent means of improving the comfort of living and working environments.
To the question "What is a heat pump "?
ENEA responds very simply by explaining that it is "a machine capable of transferring heat from one environment at a lower temperature to another at a higher temperature.”
To perform its function, theheat pumpit is equipped with a compressor, a condenser, an expansion valve and an evaporator. On a descriptive level we can compare the functioning of theheat pumpto a "cycle"which takes place within a closed circuit. On the one hand there is the compressor which, by supplying energy to the refrigerant fluid, pushes it up to the evaporator which, by absorbing the heat contained in the fluid, releases it into the environment to be heated thanks to the condenser.
More specifically, we see that while the compressor consumes electricity to start the cycle, the evaporator absorbs the heat from the surrounding medium which can be air or water (cold source *), the heat is not directly released to the environment to be re-heated but is transferred to the capacitor: in heat pump the refrigerant fluid absorbs heat from the cold source through the evaporator.
If the compressor of aheat pumpconsumes electricity, why is this system considered ecological?
In proportion, oneheat pumpis able to produce more energy in the form of heat, compared to the electricity consumed precisely because it is able to extract heat from the external environment (air-water). The efficiency of aheat pumpis measured fromCOP coefficient of performance which represents the relationship between energy supplied in the form of heat and electricity consumed. The coefficient of performance and therefore the energy efficiency of aheat pumpit varies according to the model and the operating conditions, however the average values are close to 3. This means that with only one kWh of electricity consumed, 3 kWh of heat can be generated for the medium to be heated. In “calorific” terms, 2,580 kcal of heat are produced for each kWh of electricity consumed.
When installing aheat pumpit must be borne in mind that the thermal power produced by thepumpis strictly dependent on the temperature at which it absorbs heat, i.e. on the temperature of the place where the pump is installed: if the temperature is below a range between -2 and 2 ° C, the efficiency of the heat pump is not more very appreciable because the compressor would not be able to transmit enough heat.
* The external medium from which heat is extracted is called the cold source.