Nebius
Total technical solutions for a large-scale end-to-end liquid
cooled data centre, Finland
About the project
The data centre in Mäntsälä, Finland, is a flagship site for Nebius, an Amsterdam headquartered AI cloud company. The project included an expansion of the existing building and the construction of two new data centre buildings. When completed, Nebius’ Mäntsälä data centre’s total capacity is 75 MW. It is also one of the first large-scale end-to-end liquid cooled data centres in Europe. The expansion project was Nebius' response to their customers' increased demand for their services. The Caverion’s part of the project started in May and was completed in December 2025.
The Mäntsälä data centre is one of the fastest completed data centre projects in Europe.
Operational reliability and high quality at full power
Caverion delivered liquid cooling (to complement existing air-cooling systems), heat recovery, ventilation, fire alarm, fire extinguishing and smoke extraction systems as well as electrical and HVAC installations in the existing data centre building and in the two new ones. The electric supply equipment and automated cooling systems allow Nebius to run the data centre at full power and produce the IT capacity that their customers need. High quality installation and continuous automation monitoring ensure operational reliability. The data centre utilises free cooling and incorporates a heat recovery system to direct waste heat to the district heating network.
From the customer
“The most important thing with Caverion has been their quality of work. Everything has been high quality. Also, flexibility: we have been able to arrange the whole schedule and testing in a
way that we have managed to fit everything in a tight schedule and succeed overall.”
– Juuso Vesanen, Data Center Manager, Nebius