Heat pump: construction, technology & components

How does a heat pump work? The technology and functionality can be explained relatively easily, since the work of the heat pump and components is based on a simple physical principle. Here you can find out which components are used and how the heat pump works.

Structure and function of a heat pump

A heat pump uses the same principle as a refrigerator, only in reverse. The basis for the functioning of these two systems is the Joule-Thompson effect. The structure of the heat pump and the technology are subject to a cycle:

  • Heat generation from environmental heat (heat sources: air, geothermal heat or groundwater)
  • compaction process
  • Heat transfer to the heating system
  • Cooling process of the refrigerant and recycling

The components of the heat pump

For a better understanding of how the heat pump works, take a closer look at the structure and the individual components:

Heat generation:

There are three main types of heat generation:

  • With an air heat pump, a fan takes over the constant supply of the heat pump with ambient heat.
  • Ground collectors or ground probes are important components of a heat pump that extracts heat from the ground. Frost-proof brine (water with antifreeze) circulates in the pipes.
  • An essential component of a groundwater heat pump is the well system, which consists of a suction well and an injection well.


The thermal energy obtained is transferred to the system by means of a heat exchanger. The refrigerant used has a low boiling point and therefore evaporates in the evaporator at comparatively low temperatures. The now gaseous refrigerant is then routed to the compressor.


Since the temperature of the thermal energy absorbed from the environment is not sufficient to heat a building, the compressor powered by electricity is used in the next step. The system uses the Joule-Thomson effect. The gaseous refrigerant is compressed through the use of drive energy. With the increased pressure, the temperature also rises to the desired level.


After compression, the warm gas goes to the condenser. Here, the heat is extracted from the gaseous refrigerant by means of another heat exchanger, and it automatically liquefies again. The extracted heat is transferred to the heating system at the desired flow temperature and is used to heat the premises.


The pressure is reduced via the expansion or relief valve. The refrigerant, which has now cooled down and liquefied again, is then fed back into the circuit of the heat pump and its components. The process starts over.

What does monovalent and bivalent operation of a heat pump mean?

When considering how the heat pump works, the technology and structure are crucial, and the operating mode also plays an important role. Depending on individual factors, you have the choice between monovalent and bivalent operation. The structure of the heat pump remains the same, the structural situation is particularly decisive for the operating mode.

Monovalent operation

In this operating mode, the heat pump alone takes over the supply of heating. Energetically optimized and insulated buildings offer good conditions for monovalent operation. Since only comparatively low flow temperatures are required, the heat pump can work efficiently and thus serve as the sole heating system. In many cases, it can also take over the hot water preparation at the same time.

Bivalent operation

The combination of the heat pump with other heating technologies is referred to as bivalent operation. It is possible, for example, to install a new hybrid heating system or to connect the heat pump to an existing system (e.g. gas, oil or pellet heating). This operating mode is particularly recommended for old buildings in which there has not yet been any energy optimization. Higher flow temperatures are required so that there are pleasant room temperatures throughout the house.

The heat pump: monoblock or split design?

With air-water heat pumps, you have the choice between two different designs: monoblock or split design.


With this heat pump, the components are all housed in one device, so installation is cheaper and relatively uncomplicated. However, when installing the monoblock outside, it must be remembered that there is a risk of frost for the supply lines at extreme temperatures in winter.

Split construction:

Here, the components of the heat pump are distributed over two units that can be placed flexibly. With this variant, only minor interventions need to be made to the building. On the other hand, installation and maintenance are much more complex.

Do you have questions about the structure of the heat pump or would you like advice? Call us and arrange a non-binding consultation appointment, we look forward to seeing you.