Large-scale heat pumps
Technology for low-carbon industrial and district heating
Large-scale heat pumps make environmental heat and waste heat usable at the capacity and temperature levels required by industrial processes, energy suppliers, and municipal infrastructure. They provide industrial process heat, supply local and district heating networks, recover otherwise unused heat, or combine heating and cooling in reversible systems.
For system contractors, large-scale and industrial heat pumps create long-term opportunities in industrial heat supply and the energy transition. Each system must match the available heat source, required heating capacity, supply temperature, refrigerant, and operating conditions.
BITZER provides components for large-scale and industrial heat pumps, including reciprocating, screw, and scroll compressors, heat exchangers, frequency inverters, and other electronic components. Product selection depends on the application and its operating data.
What is a large-scale heat pump?
A large-scale heat pump is a high-capacity system designed to provide heat at the capacity and temperature levels required particularly for district heating networks and industrial applications. In practice, industrial heat pumps with a heating capacity from approximately 500 kW are generally referred to as large-scale heat pumps. System capacities often extend into the multi-megawatt range.
Depending on the system design and refrigerant, large-scale heat pumps can provide supply temperatures up to +100°C and above. An industrial heat pump, by contrast, is not defined by a fixed capacity range. The term describes its field of use: it may provide process heat, recover industrial waste heat, or support combined heating and cooling. Industrial heat pumps can therefore operate in both small and large capacity ranges.
How does a heat pump work?
A heat pump extracts thermal energy from a heat source at a low temperature level and upgrades it to a higher temperature level using electrical energy. The resulting useful heat is transferred to a heat sink such as an industrial process, a district heating network or a building system.
The refrigerant circuit consists of four main components:
- Evaporator: absorbs thermal energy from the heat source. The refrigerant evaporates at low pressure and temperature.
- Compressor: compresses the refrigerant vapour. Pressure and temperature increase.
- Condenser: transfers heat to the heat sink. The refrigerant condenses and releases thermal energy.
- Expansion valve: reduces pressure and temperature before the refrigerant enters the evaporator again.
This process enables environmental heat and waste heat to be used efficiently for industrial applications, district heating and reversible heating and cooling systems.
How do heat pumps support decarbonisation?
Companies face growing pressure to make energy-intensive processes more efficient and reduce dependence on fossil fuels. Large-scale heat pumps support this transition by upgrading environmental heat and waste heat to useful temperature levels.
Typical applications include industrial process heating, district heating networks, and reversible heating and cooling systems. By replacing or supplementing fossil-fuel-based heat generation, large-scale heat pumps can reduce CO₂ emissions while improving the use of available energy sources.
For system contractors, this creates opportunities in industry, energy supply, and municipal infrastructure. Successful implementation requires the right balance between heating capacity, temperature levels, heat source characteristics, efficiency, reliability, and cost effectiveness.
BITZER supports heat pump projects with compatible components and experience in compression and heat transfer technologies.
Where are large-scale and industrial heat pumps used?
Large-scale and industrial heat pumps are used wherever low-temperature heat sources can be upgraded to provide useful heat. Applications include industrial process heating, district heating networks, heat recovery, commercial buildings, and reversible heating and cooling systems:
| Application | Heating capacity | Examples |
| Commercial buildings | 50 kW to megawatt range | Air/water, water/water and brine/water heat pumps as well as reversible liquid chillers |
| Industrial process heating | 50 kW to megawatt range | Drying processes, electroplating and other thermal processes; standard solutions or individually designed systems |
| District heating | Several hundred kW to >100 MW heating capacity | Local district heating networks, residential districts and industrial heating networks; customised, modular systems |
| Heat recovery | Application-dependent | Use of thermal energy from exhaust air, waste heat, data centres, refrigeration systems or industrial processes |
| Reversible heating and cooling | Application-dependent | Reversible liquid chillers, heat pumps with cooling function and four-pipe systems for simultaneous heating and cooling |
When does a heat pump operate efficiently?
This efficiency is supported by:
- suitable supply temperatures
- a properly designed heat distribution system
- consistently available heat sources
- efficient components, especially the compressor
The coefficient of performance (COP) describes the ratio between heating capacity and electrical drive energy under defined operating conditions. The seasonal coefficient of performance (SCOP) evaluates the actual efficiency of the heat pump system over an entire year. For cooling operation, the equivalent metric is the seasonal energy efficiency ratio (SEER). The achievable heating capacity and COP depend on system design and operating conditions.
Which refrigerants are suitable for heat pumps?
The choice of refrigerant depends on the system concept, operating conditions and required temperature levels. Suitable refrigerants for heat pumps should provide favourable thermodynamic properties, including high volumetric heating capacity and a high coefficient of performance (COP).
In addition to technical requirements, regulatory developments must be considered. In the European Union, relevant frameworks include the EU F-Gas Regulation 573/2024 and potential PFAS restrictions under the REACH Chemicals Regulation.
As the phase-down of fluorinated refrigerants accelerates, natural refrigerants such as propane (R290), isobutane (R600a) and CO₂ (R744) are becoming increasingly important for new heat pump systems. The optimal refrigerant depends on evaporation and condensing temperatures as well as the conditions on the heat source and heat sink sides.
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