Data Centre Heat Recovery Case Study from Carrier

Data Center Heat Recovery

Carrier Air Conditioning provide UK Chillers, Bms System, heating controllers and aircon units

Carrier’s AdvanTE3C engineers, a group of Experts in Efficiency and Environment, developed an innovative solution that turns the data center waste heat energy into a district heating energy source in Sweden.

Customer: Bahnhof
Location: Stockholm, Sweden
Project running since: January 2014


Carrier’s AdvanTE3C engineers, working closely with the Swedish Internet service provider Bahnhof and hydronic specialists, have helped to optimize an innovative cooling & heating solution turning data centers into heat sources for local district heating systems. Bahnhof has chosen this innovative solution for three of their data center facilities.


The ultra-secure Pionen data center is housed in a disused nuclear bunker deep beneath the bedrock of the White Mountains outside of Stockholm. This project was the first in a series of successes for Carrier in Sweden using the innovative waste heat recovery solution and has been up and running since January 2014. Carrier’s AdvanTE3C engineers developed the state-of-the-art system solution.

Key Benefits

  • Reuse data center energy as heating source
  • Eliminate unsightly fog
  • Provide redundancy
  • Reduced C02 emissions
  • Contributes to green building design
  • Return on investment estimated at less than 3 years


The system is comprised of two optimized Carrier AquaForce® 61XWH0802 heat-pump units installed in a series counterflow arrangement to optimize system efficiency with a custom-developed control solution. Carrier will ensure the ongoing performance and reliability of the system with a dedicated service agreement.

  • 2x 61XWH0802 AquaForce® units (<70°C hot water)
  • Heating system controls (Carrier Plant System Manager based solution with AdvanTE3C developed control solution)

Challenges and Solutions

The project presented a number of specific challenges and the resulting solution succeeded in:

  • Reusing data center energy as heating source;
  • Eliminating the use of the existing cooling towers and thus avoiding the occasional production of ‘fog’ at street level;
  • Developing a controls solution that combined with modification of the pipework design enabling the system to remain operational despite rapid pressure fluctuations and temperature changes that
    occur in the district heating system application;
  • Providing the data center with 100% system redundancy for server cooling, thanks to the existing Carrier AquaSnap® water-cooled Carrier system (two 30RWs) installed in 2013 that will remain as
    back up for the new system;
  • Achieving a “theoretical” Power Usage Effectiveness (PUE) score below 1.0 if the hot water produced from the waste heat is taken into account as part of the PUE calculation.


Following the success of the initial project, Bahnhof has put in orders for the advanced technology for two other data center sites in Stockholm.

  • The St. Erik data center, has been equipped with an AquaForce 61XWH0802 heat-pump unit and heating system controls.
  • The Thule data center, has been equipped with three optimized AquaForce 61XWH0802 heat-pump units and heating system controls.


Case Study – Data Centre Solutions

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