GEA Heat pumps: key technology for the energy transition

GEA's large heat pumps for industry are crucial building blocks on the road to significant CO₂ reductions and climate neutrality.

Due to the phase-out of coal-fired power generation, over 13 GW of thermal capacity for the provision of heat in district heating networks will be lost by 2038 and must be replaced. Ideally, this will not be done by gas-fired plants, but as climate-neutrally as possible by heat pumps that increasingly get their consumption power from renewable energies.

From hot domestic water to citywide district heating

GEA's industrial heat pumps based on high-pressure reciprocating and screw compressors range from circa 150 kW to 10 MW. GEA thus offers a wide range of heat pumps from small to medium-sized standard units to large, customized solutions. By coupling several units, even higher capacities are possible. This means GEA heat pumps can handle virtually any application from hot domestic water to citywide district heating. But each application is different and requires a tailored approach. Here, GEA experts combine their extensive process knowledge and know-how for integrated heating and cooling solutions.

How heat pumps work

Heat pumps and refrigeration systems operate on the same physical cycle principle, with a refrigerant circulating in a closed system. At low pressure, the liquid refrigerant evaporates and absorbs heat from the environment or a system to be cooled via a heat exchanger. The evaporated refrigerant is then compressed by a compressor and, under liquefaction at high pressure, releases heat back to a heating circuit before being returned to the low pressure level and into the evaporator via an expansion device. It is therefore possible to use the cooling effect in a heat pump or to serve a cooling application, or to use the waste heat in a refrigeration system.

Operating principle refrigeration systems and heat pumps

When are heat pumps particularly efficient?

Simply put, heat pumps are more efficient the less work the compressor has to do. This is the case the smaller the difference between the temperature of the source (air, water, earth - or a connected cooling circuit) and the set temperature of the heating circuit medium for energy distribution. In practice, this means that most heat pumps are more efficient when providing low temperatures for panel heating systems (usually <30 °C) in the example of building heating networks, than when providing higher temperatures for small radiators (up to 70 °C). Other examples of applications that require high system temperatures are hot water preparation in hygienically outdated drinking water installations, process applications, systems with high line losses, or unrenovated old buildings that need to be heated.

Heating and cooling with GEA heat pumps

The diversity of industrial heat pumps and GEA's portfolio make them interesting for numerous applications where both heating and cooling are required. For the optimal design of a heat pump, or even a refrigeration system or an efficient combination, the identification of all heating and cooling applications as well as their load and temperature level over the course of the year is crucial. Compared to conventional energy management consisting of a classic refrigeration system and additional fossil-fueled boilers, the efficiency can be increased many times over and the energy consumption significantly reduced. In several food factories, for example, a modern GEA heat pump that replaces old refrigeration systems and boilers at the same time has reduced primary energy consumption by 75 percent.

Solutions for the food, dairy and beverage industry

Traditionally, the food and beverage industry uses boilers for cooking or pasteurizing products, which were then cooled down again. All this leads to high energy consumption. The heat from the cooling process is too low to be reused directly. However, a heat pump can use the waste heat from the cooling system as a source and bring it to the desired higher temperature level in a highly efficient way.

By recycling heat in this way, more and more fossil fuel boilers can be phased out and CO₂ emissions greatly reduced. In addition, CO₂ emissions can be reduced to "zero" if "green electricity" is used.

The high efficiency and low maintenance of GEA heat pumps ensure a short payback period and benefit the customer throughout the long lifetime (at least 20 years) of the installation. Typical applications for GEA large heat pumps include multi-storey residential buildings, commercial buildings, industry, data centers and process applications.

The food industry in particular recognizes the significant financial and environmental benefits of using heat pumps in production processes. Most of today's food processing is a combination of heat treatment followed by cold storage for long shelf life. This combination of heating and cooling maximizes the benefits of heat pump systems. GEA heat pump technology offers energy saving benefits regardless of the industry and the extent of its use.

This is all the more relevant when you consider that in the food, dairy and beverage industries, up to 60 percent of energy consumption can be used for heating and cooling.

Solutions for district heating systems

In addition to applications in the manufacturing industry, heat pumps are also frequently used in district heating systems, where they are used not only to provide heat base load, but also as controllable heat generators. Their fast switching time fits well with large district heating networks. In these systems, heat pumps also play an important role in protecting the power grid as part of smart energy systems, where loads can be adjusted online depending on the request of the power supplier.

The heart of the matter: GEA piston and screw compressors

They are the heart and therefore literally the pump of the heat pump: GEA piston and screw compressors. GEA has the largest range of high-pressure ammonia screw compressors suitable for heat pump applications. With its large portfolio of heat pump equipment, GEA has optimized the range for low vibration levels and high efficiency. With the range of V-piston compressors available for higher pressures, GEA is now able to offer the most efficient ammonia compressor solution on the market. These compressors are specifically designed for high final compression pressure in a heat pump. They offer condensing temperatures that, depending on the design, are just as suitable for operation with low-temperature hot water as they are for providing process heat of up to 95°C.

Use of the natural refrigerant ammonia

As fluorinated gases ("F-gases") are phased out worldwide to reduce greenhouse gas emissions, natural refrigerants are the refrigerants of choice. In particular, ammonia is an environmentally friendly and cost-effective refrigerant that has no impact on global warming and does not cause harmful accumulation of fluoride compounds in nature. In particular, the outstanding thermodynamic efficiency also makes ammonia heat pumps the most energy-saving solutions. Ammonia is widely used in food processing plants, beverage and dairy industries, breweries and cold storage facilities. Thanks to improvements in compressor technology, ammonia heat pumps can now produce higher temperatures. This has paved the way for their wider use in the food, beverage and dairy industries, where waste heat can be optimized for washing, cleaning and drying products, heating water for cleaning and processing purposes, and pasteurization.