Closed Loops, Cool Cities in Germany

The summer of 2026 broke heat records across Germany, putting urban residents and office workers under physical stress. And yet in many offices in Munich, the temperature remained perfectly controlled, without a single air conditioning unit in sight. 

The city’s salvation during a succession of unprecedented heatwaves was Germany's largest district cooling center, located on the city's southern edge. From there, chilled water circulates through a network of pipes embedded in the walls and ceilings of connected buildings: quietly, invisibly, and with remarkable energy efficiency.

Similar networks are keeping other German cities cool, among them Berlin, Chemnitz, Frankfurt am Main and Hamburg. The technology offers a compelling set of advantages. It helps big conurbations mitigate the effects of climate change, is far more efficient than conventional alternatives, reduces peak electricity demand and limits the use of climate-change-accelerating refrigerants.

The expansion of district cooling infrastructure is also opening up significant business opportunities for international companies operating in Germany. “We have identified opportunities primarily for companies specializing in plant engineering, storage and control technology, and digital solutions for network operations,” says Robert Compton, an expert at Germany Trade & Invest (GTAI).

Closed loop cooling circuits

A district cooling network is a closed-loop system managed by a single operator. District cooling can cut electricity consumption by up to 70 per cent, with a commensurate reduction in CO₂ emissions, compared to decentralized individual air conditioning units. 

The approach is particularly efficient when natural cooling sources are tapped. In Munich, cool river water feeds into a closed cooling circuit designed to deliver up to 36MW of cooling capacity once fully operational. That’s enough to serve 100 large office buildings.

Alongside climate change, the boom in data center construction is a further driver of district cooling networks. According to German government projections, the country's data center capacity is set to double by 2030. Modern data centers require round-the-clock cooling, making them prime customers for district cooling operators.

Several investments by international technology providers illustrate the attractiveness of the German market. Trane Technologies, for instance, supplies district energy utilities with a key piece of equipment: compression chillers that generate the chilled water on which cooling networks depend. In 2024, the US-Irish company opened a new facility in Oberhausen, in western Germany, where it develops and distributes chillers for the European market. 

 “Given the steadily rising demand for our sustainable building cooling products,” said Trane President Claudio Zanframundo at the opening, “locating our facility here was an easy decision.”

International technology for local cooling

Most district cooling networks in Germany are operated by municipal utility companies, with real estate firms and industrial facility operators among the largest end customers.

Many international technology providers have established themselves in this market in recent years. Ireland's Johnson Controls sells large compression chillers in Germany to supply cooling networks, while Danish companies Grundfos and Danfoss provide pumps, valves, and sensor and control technology to ensure stable, energy-efficient water distribution within these systems.

Market observers, including GTAI's Robert Compton, expect the market for district cooling solutions in Germany to grow even faster in the coming years. Two forces are driving that outlook: the continued rise of data centers, and the sobering lessons of Europe’s so-called “summer of ashes” this year, which made it abundantly clear how much German cities need to change to cope with extreme heat.