High-temperature heat pump: The alternative for old buildings, industry, and apartment buildings

High-temperature heat pumps heat water to temperatures that are unattainable for conventional models: 80, 90, or 100 °C are possible with them. Industrial devices can even reach even higher values.

This makes them significantly more powerful than conventional heat pumps and enables them to supply sufficient heat even to unrenovated old buildings, apartment buildings, or industrial processes.

Like conventional heat pumps, high-temperature heat pumps use a renewable energy source—air, ground, or groundwater, depending on the system—and convert it into heating energy with the aid of electricity. They operate according to the same physical principle, but with special technology for higher temperatures and more powerful components, such as larger compressors, in order to achieve significantly higher flow temperatures. Other components are also different in order to withstand the significantly higher pressure.

1. Environmental heat from the air, ground, or water is transferred to a refrigerant via an evaporator.
2. The refrigerant evaporates even at low temperatures, becoming gaseous, and is compressed in the compressor.
3. The compression causes the temperature to rise sharply.
4. In the heat exchanger, the heat generated in this way is transferred to the heating water.
5. The refrigerant then liquefies and the cycle begins again.

Want to know more? Then read our guide article “How does a heat pump work?”.

Using the process described above, standard heat pumps can reach temperatures of up to 60 °C, and in some cases even over 70 °C.

TYPES OF HIGH-TEMPERATURE HEAT PUMPS

High temperatures of 100 °C and above are achieved using different technologies. Different designs are used depending on the area of application.

These are the most common types:

• Dual-circuit high-temperature heat pump: This type of heat pump is mainly used in residential buildings. Two refrigerant circuits connected in series gradually increase the temperature: the first works like a standard heat pump and reaches 40 °C, while the second circuit then increases the heating water to up to 90 °C. The condenser of the first circuit is the evaporator.
  
  
• CO2-heat pump: As the name suggests, CO2 is used as a natural refrigerant here. CO2 has special thermodynamic properties and is very good at absorbing and releasing heat, among other things. It is therefore particularly suitable for high temperature differences. Here too, flow temperatures of 90°C are possible – suitable for industry and district heating networks. The CO2 heat pump is often used where industrial waste heat, cooling water, and wastewater are available as heat sources. It is ideal for industrial applications or for feeding into district heating networks.
  
• Hot gas heat pump: This type uses a highly compressed hot refrigerant, known as hot gas. This is used to heat domestic water (drinking water) to 65 °C and above without compromising the efficiency of the heating circuit. The hot gas heat pump is therefore particularly suitable for new buildings where low flow temperatures are sufficient for the heating system, but the drinking water requires higher temperatures for hygienic heating.

High-temperature heat pumps are used wherever the usual 55 to 60 °C flow temperature of a standard heat pump is not sufficient. Higher temperatures are required for heating or hot water, particularly in unrenovated old buildings, for drinking water preparation in large residential buildings, or for industrial processes and production processes.

High-temperature heat pumps are a suitable alternative to oil or gas in these areas:

INDUSTRY & COMMERCE

Processes such as metal hardening, drying, pasteurization, or washing require a constant supply of heat. A high-temperature heat pump can provide this in a climate-friendly and reliable manner. It is particularly efficient when existing industrial waste heat can be used as an additional heat source.

OLD BUILDINGS

Heat pumps and unrenovated old buildings are not a good match. Poorly insulated and equipped with old radiators, even a heat pump cannot achieve energy efficiency. High-temperature heat pumps, on the other hand, provide cozy warmth even without additional insulation measures thanks to their high flow temperatures. Existing heating structures such as old radiators and old pipes can continue to be used.

MULTI-FAMILY HOUSES

To ensure hygienically safe hot water, flow temperatures of at least 60 °C and above are required. High-temperature heat pumps reliably achieve this value. They therefore offer an efficient solution for central hot water supply in multi-family houses.

Tip: For older buildings, bivalent systems can also be a solution. In this case, the heat pump is combined with a gas boiler, for example.

As a general rule, the higher the target temperature and the higher the temperature rise, the more electricity is required. This is why high-temperature heat pumps are usually less efficient than standard models.

• COP (coefficient of performance): This indicates the approximate heat output of 2.5 for HT heat pumps
• JAZ (annual performance factor): 2.0 to 2.5 (for comparison: standard heat pumps approx. 3.5)

Nevertheless, their use can be worthwhile, especially with PV electricity and favorable heat pump electricity tariffs.

• Single-family home: approx. 10.000–20.000€ (plus installation)
• Multi-family home/industrial: Up to 80.000€, depending on the size of the building

Air-to-water heat pumps are the most affordable, while geothermal and groundwater heat pumps incur higher development costs.

Get a non-binding quote!

With high-temperature heat pumps, you can achieve higher temperatures without electricity consumption skyrocketing, as would be the case with conventional models under full load. Nevertheless, they consume a lot of electricity depending on the flow temperature.

ADVANTAGES

• Very high flow temperatures enable use in old buildings and industrial processes.
• There is no need to renovate old buildings and existing radiators can continue to be used. This means that no investments or structural changes are necessary.
• By using environmental heat and, in particular, waste heat in industry, energy costs can be saved in the long term.
• When purchasing, government subsidies of up to 70% or tax advantages can be claimed.
• They are climate-friendly and reduce the consumption of fossil fuels, thus providing a low-CO₂ alternative to oil or gas heating systems, even in industry. In this way, they help to meet climate targets.
• High-temperature heat pumps can supply entire neighborhoods via district heating networks.

DISADVANTAGES

• Compared to conventional heat pumps, electricity consumption and thus costs can be higher.
• A high-temperature heat pump is currently still less efficient than conventional heat pumps.
• In addition to higher operating costs, higher acquisition costs also have an impact.

To find out whether a high-temperature heat pump is really worthwhile for your specific situation, it is important to carefully weigh up the pros and cons. In some cases, it may be cheaper to reduce energy consumption through other measures such as insulation or replacing radiators and to use a standard heat pump. It is best to seek individual advice on this.

Schedule a consultation now!

High-temperature heat pumps are an important component in the heat transition. Like standard heat pumps, they are the heating technology of the future: efficient, climate-friendly, and cost-saving in the long term. They bring climate-friendly heat within reach in areas where this was previously unthinkable: in industry, in heating networks, and in unrenovated old buildings.