European data center operator Kolo has announced the opening of DK5, a colocation facility in Copenhagen that uses water-cooled propane (R290) chillers for server cooling.
The company made the announcement on LinkedIn, with a subsequent post from DataCenterGruppen, a Danish supplier of data center solutions that worked with Kolo on the project, stating that the servers are cooled with a cooling system using natural refrigerants and a “very efficient” modular free cooler. DataCenterGruppen shared further information about the cooling equipment and the colocation facility’s installed IT power capacity with NaturalRefrigerants.com via email.
Partial free cooling is available at ambient temperatures from 16 to 21°C (60.8 to 69.8°F) and full free cooling is available at ambient temperatures below 16°C. It’s projected that full free cooling will be available approximately 7,000 hours per year with partial free cooling available from 5–800 hours annually.
The data center’s installed IT power capacity is approximately 400kW, although that could be expanded in the future. DK5 features liquid-cooled “high-density” server racks that can exceed 30kW of installed IT capacity per cabinet, according to Kolo, which added that the colocation facility is “purpose-built for technology companies deploying AI inference workloads that require sustained high-density computing and urban connectivity.”
Kolo operates five data centers in Denmark and also has facilities in Sweden and the Netherlands. The company is owned by CapMan Infra, a branch of the Finland-based private equity fund manager CapMan.
Natural refrigerants in data centers
Due to the secretive nature of the industry, information on natural refrigerants in data centers has been hard to come by. That said, in 2024 Danish manufacturer Advansor published a case study detailing the transcritical CO2 (R744) racks with a total cooling capacity of 1.3MW (369.6TR) that it provided for a data center in Valencia, Spain. The data center, operated by KIO Networks, claims to be Spain’s first to use 100% natural refrigerants.
At the 2024 ATMO Europe Summit, Italian ammonia (R717) chiller and heat pump manufacturer Zudek presented a case study on an ammonia chiller it provided to cool a data center in Germany. The data center, located in the state of Baden–Württemberg, cut its energy consumption for cooling by 43% after replacing its 790kW (224TR) R407C-based chiller with a new Zudek unit of equivalent size. The ATMO Europe Summit was organized by ATMOsphere, publisher of NaturalRefrigerants.com.
