Heat pumps in industry – how do they work and where are they used?

What is a heat pump?

A heat pump is a heating device that uses thermal energy from the environment – from air, water, ground, or waste heat – and transfers it to a selected medium, most often water or air, which is then fed into a heating or process system. The process occurs via a thermodynamic cycle involving a heat transfer medium and a compressor. In simple terms, a heat pump "pumps" heat parameters, increasing the performance of low-temperature heat.

Industrial applications are dominated by water-to-water and air-to-water heat pumps, including high-temperature units that achieve medium temperatures above 100°C – sufficient for many technological processes. This technology allows not only for heating but also for cooling, using various heat sources (e.g., heat recovery during the technological process), making it a flexible solution for manufacturing plants.

How do heat pumps work in industrial plants?

Industrial heat pumps can perform many functions – from heating production, warehouses, and offices to heating domestic or process water, producing low-temperature steam, and being used in air conditioning and refrigeration systems. They are also increasingly used for waste heat recovery from industrial processes.

The operating principle involves five basic stages:

• heat extraction from the lower source (i.e., the source from which the pump extracts thermal energy),
• compression of the refrigerant (using electricity),
• expansion of the refrigerant,
• transfer of heat to the upper source (e.g., the heating system, which is the recipient of the generated energy),
• condensation of the refrigerant – often using the lower source and its reuse.

The entire cycle can operate continuously. The efficiency of a heat pump is expressed by the COP – the higher its value, the less electricity is required to obtain a given amount of thermal energy.

What are the differences between heat pumps used for home heating and industrial heat pumps?

• scale of operation – industrial heat pumps have significantly greater power (up to hundreds of kW or several MW), allowing them to operate in production halls, production lines, or technological processes,
• supply temperature – higher temperatures are often required in industry (e.g., 70–90°C), while domestic heat pumps typically heat water to 35–55°C,
• heat source and sink – industrial heat pumps often use non-standard heat sources, such as process wastewater or process air, and transfer the heat to more complex systems (e.g., dryers, washers, HVAC systems),
• operation mode – in industry, pumps often operate continuously or at high intensity, and their operation is integrated with plant automation.

Where can heat pumps be effectively used in industry?

"The efficiency of heat pumps in industrial plants depends on the availability of heat sources and the type of production processes." The greatest potential lies in locations where waste heat is generated – for example, from cooling systems, ventilation, air compressors, or process water. Where low- or medium-temperature heat is needed, and cooling is also required, a heat pump can handle both tasks simultaneously. Efficiency also increases when the device can be powered by renewable energy sources, such as a photovoltaic system.” says Przemysław Wojciechowski, Project Manager at DB Energy.

Heat pumps are widely used in various industrial sectors – from heating and cooling production buildings, through domestic hot water preparation, to powering technological processes requiring specific temperatures. They are suitable for both new investments and modernized plants, where they can replace or supplement traditional heat sources.

Industries where heat pumps are best used

Heat pumps are used in many industrial sectors. In the food industry, they are used to heat process water, recover heat from refrigeration systems, and support CIP (Clean-in-Place) cleaning systems. In breweries, dairies, and fruit and vegetable processing plants, their use leads to significant energy savings.

In the chemical and pharmaceutical industries, heat pumps ensure temperature stability of media and support HVAC systems in maintaining production conditions. Their advantages include clean operation and the ability to precisely control temperature, which is crucial in these industries.

In paper and wood processing plants, heat pumps support wood drying processes, hall heating, and recover energy from fans and dryers. In the automotive and machinery industries, they are used to recover waste heat from process equipment, as well as to heat liquids and air in industrial washers.

In the textile sector, this technology supports drying processes, air conditioning, and the heating of process baths. Additionally, in each of these industries, heat pumps can support heating systems in offices and staff rooms.

Advantages of using heat pumps in industrial plants

The main advantages of industrial heat pumps include, above all, high energy efficiency. COPs of 3.5–4.5 mean that several units of thermal energy can be obtained from each unit of electricity. This translates directly into reduced plant operating costs – especially when using heat pumps for waste heat recovery or in combination with photovoltaics. In the long term, this allows for reduced consumption of natural gas or heating oil.

Heat pumps also contribute to the reduction of CO₂ emissions. Their use supports the achievement of companies' climate goals, particularly in the electrification of heat sources, improves ESG reporting scores, and can be a valuable asset in discussions with contractors and investors. Their versatility is also worth emphasizing – the pumps can be integrated with energy management systems, energy storage systems, and other heat sources, making them an attractive element of industrial plants' energy transformation strategies.

Disadvantages and limitations of heat pumps in industry

One of the main challenges associated with heat pump installation is the high investment cost, especially for high-power units or those operating in high-temperature ranges. Implementing an industrial heat pump system often requires modernizing existing installations and adapting the technical infrastructure.

Another limitation may be the reduced efficiency of air-to-water heat pumps at low ambient temperatures, which is significant in winter. In such cases, ground-source heat pumps or hybrid systems are recommended. Proper system design is also crucial – incorrectly selecting the pump power, failing to analyze the energy consumption profile, or underestimating demand can significantly reduce the profitability of the investment.

Heat pumps do not always achieve temperatures sufficient for the most demanding technological processes – in such cases, the use of support systems, such as boilers or gas burners for supplementary heating, may be necessary.

Heat pumps in waste heat recovery

One of the most cost-effective applications of heat pumps in industry is their use for waste heat recovery. In many industrial plants, a significant portion of energy is lost as low-temperature heat, which is not suitable for direct reuse. A heat pump can raise the temperature of this heat to a usable level and return it to the cycle.

Recovery can involve, among other things, ventilation air, process water, steam condensate, condensate from refrigeration systems, or heat generated by air compressors. This approach reduces energy losses and improves the plant's energy balance, which directly translates into lower production costs. It is also a source significantly less affected by outside temperatures, allowing heat pumps to be used efficiently year-round.

Summary

Heat pumps are a modern and versatile solution for industrial energy efficiency. Using them in production plants not only reduces operating costs but also improves environmental performance and independence from fluctuating fossil fuel prices. The greatest potential of this technology lies in waste heat recovery, integration with renewable energy sources, and applications requiring simultaneous cooling and heating. However, this requires a well-thought-out design and adaptation of the system to the specifics of a given plant.