A datacentre supplies local heating in Mäntsälä, Finland

This case study is part of a project catalogue produced by ReUseHeat to inspire how to utilize excess heat from urban sources for heating and cooling purposes. The catalogue contains 25 existing or planned projects, of which 12 cases are Danish and 13 from other European countries.

Description

The city of Mäntsälä, located approximately 55 km north of the Finnish capital Helsinki, installed a heat pump capable of heating 1500 homes. The heat pump extracts heat from a nearby data centre.

Hot air from data centres holds a huge potential for energy recovery. By removing the air and utilizing the excess heat, it can be used in local district heating networks. In 2015, Mäntsälä installed a 4.0 MW heat pump that utilizes the excess heat from the local Yandex data centre.

Heat exchangers extract hot air from the data centre servers at temperatures of approximately 40 degrees Celsius. This air is used in the heat pump, where the temperature is increased to approximately 85 degrees Celsius. The heat pumps are optimized to achieve high temperatures, thereby having a high COP, which potentially can be above 4.0. The heat pump does not affect the design of the data centre, as energy is harvested from the outgoing airstream. Extra fan power is added to the building to extract the server's heat.

By extracting waste heat from the computing centre, 75% of the energy originally used can be reused. Further, the excess heat replaces natural gas heating and hereby reduces the annual CO2-emission with approximately 4000 tons of CO2 in the first years, which later can be up to 11,000 tons of CO2. The heat pump can supply 1500 homes with heating through the district heating network. Later, as the district heating network is to be expanded, this number can rise to about 4000 homes.

ReUseHeat, IVL Swedish Environmental Research Institute, Nivos Energia

External links:

Calefa, Yandex data center, Handbook – 25 cases of urban waste heat recovery