Let's talk about thesizing of heat pumps, in other words, of how choose the power of the heat pump that we intend to install to heat our house or apartment.
The assessments to be made to choose the power of the heat pump reside in several factors:
- dimensions of the rooms to be heated
- type of insulation of the rooms to be heated
- exposure of the apartment to be heated
- will the heat pump only be used for domestic heating?
- Will the power of the heat pump also be used to produce domestic hot water?
- Will the heat pump also have to provide cooling for the apartment?
A first calculation to determine thesizing of the heat pumpcan be performed taking into account only theheat requirement of the apartmentto be heated. It is a simple mathematical calculation that determines how much energy is needed to heat an environment, the same mathematical calculation seen in the article entitledHow to choose the power of the boiler. This calculation will suffice if you want to use theheat pumponly for domestic heating but it will not be enough in other cases.
- Sizing of the heat pump:
choose the power of the heat pump when this must also provide for the production of domestic hot water
For normal comfort levels, a maximum hot water requirement of 80 - 100 liters per person per day must be considered. In this case, to estimate thepower of the heat pumpit will be necessary to add 0.2 kW for each person.
Not only will it be necessary to consider the maximum number of people but also if there are particular habits such as the use of a Jacuzzi or a heated swimming pool. The regulation of the production of hot water with a heat pump takes place by means of a programmer which, according to the needs, activates the production of hot water in an optimal way.
In reversible heat pumps with additional heat exchanger it is possible to use the residual heat produced in cooling operation to produce hot water.
If an electrical resistance is used in the hot water storage system, this can be used at the design point to produce hot water: in this case the power of the heat pump for preparing hot water must not be added to the load. thermal!
In reality, for the sizing of a heat pump that produces domestic hot water, it is not only necessary to estimate the amount of hot water used by the inhabitants of the house. Attention should also be paid to traffic drivers. The circulation conductors are those that bring hot water into the various domestic environments, making it immediately available, however, the pipes significantly increase the heat requirement (andpower) for water heating.
A higher power of the heat pump may depend on the length and quality of the conductor insulation. If the conductors are very long, the installation of a recirculation pump may be recommended, which is activated only in case of need by means of a flow sensor or something similar.
Recommended reading:How to choose the heat pump