Heating in XXL Format

Heading

Heat Pumps for Heating Private Properties are now established - and they are becoming increasingly important in Industry and Commerce.

It has the dimensions of a football field, can generate 150 tons of steam per hour, and saves 390,000 tons of CO2 annually. These are the key features of one of the world's largest industrial heat pumps, which the chemical giant BASF plans to build at its Ludwigshafen site in collaboration with MAN Energy Solutions. Because in the chemical industry, nothing works without steam; it is used for drying products, heating reactors, or distillation, among other things. BASF alone requires around 20 million tons of it annually at its headquarters – a portion of which the planned large heat pump is intended to generate using electricity from renewable sources and waste heat from the cooling water system.

The dimensions of the project are extraordinary, but heat pumps in industry and commerce, in general, are no longer exceptional. While the exact number of devices in use in Germany in this sector is still being evaluated by the German Heat Pump Association based on a survey for 2022, one thing is already clear: heat pumps offer enormous potential for building heating and cooling as well as for generating process heat.

It is precisely this last aspect that makes heat pumps so interesting for the industry. According to the Fraunhofer Institute for Solar Energy Systems ISE, in 2018, about one-fifth of Germany's final energy demand for process heat – which includes steam used at BASF – was used. The lion's share of this heat is generated by the combustion of fossil fuels. From the perspective of climate protection, it is necessary to shift to heat generation using electricity from renewable energies. According to the Fraunhofer Institute, heat pumps can generate the necessary temperatures, which are suitable for most processes and range from less than 150 degrees Celsius, with good efficiencies, providing process heat in large power classes steadily.

An example from Pocking in Bavaria illustrates what a water heat pump can achieve in terms of heating and cooling on a large scale: The local Inntal greenhouse, after the construction of a more than 30,000 square meters plant and logistics center, is one of the largest operations of its kind in the region. A large heat pump, utilizing the high groundwater level due to its proximity to the Inn, ensures energy-efficient heating. The system with a capacity of 1,560 kW supplies the underfloor heating in the greenhouses – temperatures of up to 35 degrees Celsius are possible, and 80% of the energy requirement is covered by using groundwater. Since the plants should not get too hot, the heat pump can return excess heat to the groundwater using its cooling function, for which only a circulation pump is necessary (see also the box on the cooling function of heat pumps).

The Deutsche Bahn in the Nippes district of Cologne has gone to a bit more effort, where the first CO2-neutral ICE maintenance facility is located on an area of more than 22,000 square meters – up to 16 long-distance trains can be serviced there every night. Three large heat pumps, powered by a 2,100 square meter photovoltaic system, provide climate-friendly heating for the area and its buildings, with the heat pump's output totaling 4.9 MW. The hot water supply is provided by a solar thermal system with a capacity of 100 kW. Overall, the combination of different technologies saves more than 1,000 tons of carbon dioxide emissions annually.

Whether a corporation, medium-sized company, or small business, companies that want to use heat pumps must comply with legal requirements. These vary depending on whether the heat source is the ground, air, or water. Similarly, the requirements of the respective responsible state authorities may vary. This is particularly true for drilling into the ground; therefore, a precise inquiry into the necessary permits should be one of the first steps in plant planning – as a bonus, the state offers (still) relatively high subsidies for the development of geothermal energy for heat pumps.

For devices that use water as a heat source, a water analysis is required in advance, and drilling is, of course, subject to approval. Substantial financial subsidies from the federal government are also possible. An exception is air-source heat pumps because they do not require special permits. However, legal regulations for noise protection must be observed because the devices draw in air using large fans – at BASF in Ludwigshafen, they would probably be glad to only face such comparatively small challenges.

Not Just Hot Air

The name may not suggest it, but heat pumps can also cool. This can be crucial in industrial contexts when central functions are temperature-sensitive – an example is large servers that generate a lot of heat in the building and must not overheat themselves.

Normally, in heating mode, a heat pump absorbs heat from the air, water, or ground and transfers it to a circulating refrigerant, which then vaporizes. A compressor compresses the gas, making it hot. The refrigerant is then condensed and releases heat, for example, to the water in heating pipes. In cooling mode, this process runs in reverse: the heat pump absorbs heat from the building and releases it into the surrounding air. Because the compressor is in operation, this is called active cooling.

In passive cooling, no compressor is needed, and building heat is simply directed into the cooler ground using a circulation pump. The big advantage of this variant: the ground can partially store the dissipated heat, making it available to the heat pump later for heating.