Data centre heat recovery with R1234ze heat pumps

FINLAND:  Heat pumps using R1234ze refrigerant are to be deployed in what is claimed will be the largest system for recycling waste heat from data centres in the world.

The waste heat from a new Microsoft data centre complex being built in Finland will supply district heating for a city and two other communities in the Helsinki metropolitan area.

Finnish heat pump manufacturer Oilon will supply the state-owned energy company Fortum with the industrial heat pumps required by the heat recovery system’s two plants. The heat pumps will provide cooling to the data centres, recover the waste heat generated, and transfer the recovered energy into the local district heating network.

For Oilon, this contract, valued at around €15m, is the largest in the company’s history.

Oilon will deliver several of its S series heat pumps running on the HFO refrigerant R1234ze. Each plant has an output temperature of 85°C. Together, the two plants will produce nearly 40MW of district heating, achieving COPs of 6.6.

The first heat pump plant is currently being built in Kirkkonummi, and the first heat pumps will be delivered to the site in early 2025. The Espoo project will follow a half year later. In all, the infrastructure includes about 900km of underground pipes. 

At full capacity, it is claimed that the waste heat recovery system will produce enough district heating for 100,000 customers. This accounts for 40% of the 250,000 district heating customers in Espoo, Kauniainen, and Kirkkonummi. 

It is said that the two heat pump plants will correspond to more than 1% of the emission reduction required for achieving Finland’s carbon neutrality target.