Gebäudekühlung: Warum leitungsgebundene Kälte kaum vorankommt

Potsdamer Platz is often considered an example of urban development that is not people-friendly. However, during the construction of the city's technical infrastructure, the developers made a decision that has paid off in the long run: they installed a cold network. According to the operator BEW Berliner Energie und Wärme (BEW), the cold center in Stresemannstraße today supplies around 12,000 offices, 1,000 apartments, and numerous cultural institutions.

The cold flows through a network of 14 kilometers and replaces decentralized cooling in buildings. Long-distance cooling is referred to as a counterpart to district heating due to its centralized generation and distribution. While the federal government is continuously adapting laws for heating networks, cold networks play a subordinate role.

Despite this, cooling systems and urban heat protection concepts are gaining political momentum after the record heat waves in 2026. Cold networks are valuable for new residential developments, as the unique combination of an empty plot and a sufficient number of potential customers in the inner-city location makes it rare but urgently necessary for the expansion of cold networks.

Alexander Garbrecht, head of district heating facilities at BEW, explains that during the development of the current quarter, the opportunity was used to build a cold center right next to it and to consider the necessary pipeline infrastructure from the beginning. The cold center supplies water at a temperature of six degrees Celsius to the connected buildings.

The water absorbs heat and heats up to twelve degrees Celsius. It is cooled back in the cold center through two methods: absorption and compression. Compression cooling systems work much like a refrigerator. Inside, a refrigerant evaporates when in contact with the heated water and cools it down. The steam is then compressed, the temperature rises – and the refrigerant releases its heat in the condenser, becoming a liquid.

From there, it returns to the evaporator. The only energy source is electricity, so the environmental friendliness of this method depends on the electricity mix. At absorption, a refrigerant is first evaporated. This is then condensed elsewhere (condensation). The processes are spatially separated, which means that heat is removed from the environment – in this case, the water in the cold pipeline – during condensation.

BEW uses district heating from the Mitte power plant for this, which is needed less in summer when hardly anyone heats, but a basic heat supply is still generated. Heat protection concepts are also a matter of prioritization. BEW believes that cold networks can be efficient and climate-friendly for new residential developments where the conditions are right.

"Where the prerequisites are met, a shared cooling supply can be more efficient and climate-friendly than many individual cooling systems in the buildings," says Susanne Huneke, head of strategy, politics, and regulation at BEW. However, there is no single new cold network in concrete planning. Cold and urban heat protection measures are only important in specific planning scenarios, as they reduce heat directly in the urban area.

Large cold networks remain an exception due to their high initial investment and the necessary compression. Smaller combined solutions, also known as cold district heating or fifth-generation heating networks, could be more frequently used. These pipelines can also transport heat away and cool buildings, but they do so in winter as well as a heat supplier.

These networks can explore local heat sources that classical heating networks often have a too low temperature level and combine heat supply and cooling in a common infrastructure. However, a complete and systematic overview of these projects does not yet exist. The recently founded BVKW (Bundesverbund Kalte Nahwärmenetze) is working on such an overview, estimating several hundred projects in planning or already implemented.

They are also working on defining the specific technology of cold district heating to make it eligible for specific funding. Cold district heating does not replace air conditioning systems, as the cooling effect works differently. "Imagine cold"