Focus on heat pumps

The coefficient of performance of a heat pump is also called COP (coefficient of performance) and is an important indicator of efficiency. The COP value always refers to a defined operating point and describes the ratio of electrical power consumed to heat output delivered. A COP value of 4.96 (A2/W35) for an air/water heat pump means, for example, that at an air temperature of 2°C (=A2) and a flow temperature of 35°C (=W35), 1 kW of electrical energy produces 4.96 kW of heating capacity. In principle, therefore, the higher the COP value, the more efficiently the heat pump works and the less electricity it requires to operate.

Yes, heat pumps are also a sensible and environmentally friendly heating solution for old buildings. They utilise free energy from the air, water or earth, making you independent of rising oil and gas prices. However, in order for the heat pump to work efficiently in an old building, a few requirements must be met: Good insulation of the roof, façade and windows is important to minimise heat loss. It should also be checked whether the existing radiators can provide the desired level of heating comfort even with the lower temperatures of the heat pump. Replacing the old radiators with special, particularly efficient heat pump radiators may make sense here.

Heat pumps can also be operated with modern (flat) radiators without any problems. The flow temperature - i.e. the temperature to which the water is heated before it enters the heating circuit - is crucial for efficient operation. Heat pumps work particularly efficiently at low flow temperatures. For this reason, radiators should be used that bring the desired thermal comfort into the rooms at such low temperatures. Older radiators often do not achieve this and should be replaced with modern radiators. Special heat pump radiators, which are optimised to the requirements of the heat pump and thus enable maximum efficiency, are particularly effective.

The structural requirements for the installation site differ depending on the type of heat pump. Air-to-water heat pumps are the easiest to install. A stable substrate should be available for outdoor installation. Devices for indoor installation require a room, e.g. in the basement, that has load-bearing capacity and is well ventilated.

Brine / water heat pumps, on the other hand, require geothermal collectors to be laid over a large area or geothermal probes to be installed at depth. This requires either a large, unsealed area (collectors) or a soil expertise (probes). For water-to-water heat pumps, two wells must be drilled to transport the groundwater to the heat pump. As a rule, this access must be authorised.

Due to these structural preparations, brine / water heat pumps are usually more suitable for new buildings or major refurbishments, while air / water heat pumps are also suitable for retrofitting existing buildings.

Whether a permit is required depends on the type of heat pump. Air-to-water heat pumps and brine / water heat pumps with geothermal collectors generally do not require a permit, as no deep drilling into the groundwater is necessary. With air-to-water heat pumps, however, attention should be paid to the distance to the neighbouring property, as the devices can cause noise during operation.

For water-to-water heat pumps, on the other hand, a permit is required as deep drilling is required and groundwater is used. The regulations vary depending on the federal state. It is therefore important to obtain information in advance from the relevant water authority and the geological service.

A combination of heat pumps and photovoltaic systems is not only easily possible, but also makes sense. Heat pumps require electricity to operate. By combining them with photovoltaic systems, they can be operated with self-generated, green electricity in a way that conserves resources and saves costs. The x-change dynamic heat pumps from KERMI enable the intelligent use of PV electricity to generate heat on demand thanks to the built-in power-to-heat function. The heat generated is stored in a heat storage unit and is then available when needed.