Heat pumps in industry – how they work and where they are effective
Heat pumps are increasingly appearing not only in residential construction but also in the industrial sector. Their growing popularity stems from the need to reduce energy costs, improve energy efficiency, and lower CO₂ emissions. A heat pump produces heat with potentially high parameters by using low-parameter heat from a lower source and electrical energy. It extracts heat from the environment - such as the ground, air, water, or waste heat - and raises its temperature through the thermodynamic work of a gas compressed by an electric compressor, which then transfers the heat to the heat exchangers of a heating or technological installation.
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 to water or air, which then goes to the heating or technological installation. The process occurs thanks to a thermodynamic cycle involving a refrigerant and a compressor. Simply put, the heat pump "pumps" heat parameters by increasing the usable parameters of low-temperature heat.
In industrial applications, water-to-water and air-to-water heat pumps dominate, including high-temperature units that achieve medium temperatures above 100°C – sufficient for many technological processes. This technology allows not only heating but also cooling by utilizing various heat sources (e.g., heat recovery in technological processes), making it a flexible solution for production plants.
How do heat pumps operate in industrial plants?
Heat pumps in industry can perform many functions – from heating production, storage, and office spaces, through heating domestic or technological water, producing low-parameter steam, to use in air conditioning and cooling systems. Increasingly, they are also used to recover waste heat from industrial processes.
The principle of operation consists of five basic stages:
- heat uptake from the low-temperature source (i.e., the source from which the pump absorbs thermal energy),
- compression of the refrigerant (using electric energy),
- expansion of the refrigerant,
- heat transfer to the high-temperature source (e.g., the heating installation, i.e., the receiver of the produced energy),
- condensation of the refrigerant – often using the low-temperature source and its reuse.
The entire cycle can operate continuously. The efficiency of the heat pump is expressed by the COP coefficient – the higher its value, the less electric energy is needed to obtain a certain amount of thermal energy.
What distinguishes heat pumps used, for example, for heating houses from industrial heat pumps:
- scale of operation – industrial heat pumps have much higher power (even hundreds of kW or several MW), which allows them to serve halls, production lines, or technological processes,
- supply temperature – industry often requires higher temperatures (e.g., 70-90°C), while home pumps usually heat water to 35–55°C,
- heat source and receiver – industrial heat pumps often use atypical heat sources, e.g., technological wastewater or air from processes, and deliver heat to more complex systems (e.g., dryers, washers, HVAC systems),
- operation mode – in industry, pumps often operate continuously or with high intensity, and their operation is integrated with plant automation.
Where can heat pumps be effectively used in industry?
Efficiency of heat pumps in industrial plants depends on the availability of heat sources and the type of production processes. The greatest potential lies where waste heat occurs – e.g., from cooling systems, ventilation, air compressors, or process water. Where low or medium temperature heat is needed and there is simultaneously demand for cooling, the heat pump can perform both tasks at the same time. Efficiency also increases when the device can be powered from renewable energy sources such as photovoltaic installations.
Heat pumps find wide application in various industrial areas – from heating and cooling production buildings, through preparing domestic hot water, to supplying technological processes requiring specific temperatures. They work well both in new investments and in modernized plants, where they can replace or support traditional heat sources.
Industries where heat pumps work best
Heat pumps are used in many industrial sectors. In the food industry, they are applied for heating process water, recovering heat from refrigeration systems, and supporting 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 the temperature stability of media and support HVAC systems in maintaining production conditions. Their advantages include clean operation and precise temperature control, which is crucial in these industries.
In the paper and wood industries, heat pumps support wood drying processes, heating halls, and recovering energy from fans and dryers. In the automotive and machinery industries, they are used to recover waste heat from technological equipment, as well as to heat liquids and air in industrial washing systems.
In the textile sector, this technology supports drying processes, air conditioning, and heating of process baths. Additionally, in each of these industries, heat pumps can support heating systems in offices and social spaces.
Advantages of using heat pumps in industrial plants
The main advantages of industrial heat pumps include high energy efficiency. COP coefficients at the level of 3.5–4.5 mean that several units of thermal energy can be obtained from each unit of electrical energy. This directly translates into reduced operating costs for plants – especially when using heat pumps for heat recovery or in combination with photovoltaics. In the longer term, this helps reduce the consumption of natural gas or fuel oil.
Heat pumps also contribute to reducing CO2 emissions. Their use supports companies in achieving climate goals, particularly in electrifying heat sources, improves ESG reporting results, and can serve as an argument in discussions with contractors or investors. It is also worth emphasizing their versatility – pumps can be integrated with energy management systems, energy storage, and other heat sources, making them an attractive element of industrial energy transformation strategies.
Disadvantages and limitations of heat pumps in industry
One of the main challenges related to the installation of heat pumps is the high investment cost, especially for large-capacity devices or those operating in high temperature ranges. Implementing an industrial heat pump system often requires modernizing existing installations and adapting technical infrastructure.
Another limitation may be the decrease in efficiency of air-to-water heat pumps at low ambient temperatures, which is important during the winter season. In such cases, ground-source pumps or hybrid systems are recommended. Proper system design is also essential – incorrect pump sizing, lack of energy consumption profile analysis, or underestimating demand can significantly reduce investment profitability.
Heat pumps do not always reach temperatures sufficient for the most demanding technological processes – in such cases, supporting systems may be necessary, e.g., boilers or gas burners for additional heating.
Heat pumps in waste heat recovery
One of the most cost-effective applications of heat pumps in industry is their use in waste heat recovery. In many industrial plants, a significant portion of energy is lost as low-temperature heat that cannot be reused directly. With a heat pump, it is possible to raise the temperature of this heat to a usable level and return it to the system.
Recovery may include, among others, ventilation air, process water, steam condensate, condensate from refrigeration systems, or heat from air compressor operation. This approach reduces energy losses and improves the energy balance of the plant, which directly translates into lower production costs. It is also a source much less dependent on external temperatures, which allows for efficient use of heat pumps throughout the year.
Summary
Heat pumps are a modern and versatile solution in the field of industrial energy efficiency. Their use in production plants allows not only to reduce operating costs but also to improve environmental indicators and reduce dependence on fossil fuel price fluctuations. 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 the plant.
