Heat Reuse: A Management Primer

Overview

The report was published as UII Briefing Report 114 in October 2023 and covers the current state of waste heat recovery in data centers and the drivers for the next few years. Its author is M. Smolaks.

According to the public information, Northern Europe leads with nearly 60 documented heat recovery projects. Citing the Open Compute Project, the introduction mentions around 60 projects in Europe and six in North America, with 11 more in development. The figures suggest that heat reuse is concentrated in particular regions rather than being a widespread practice.

The most important regulatory element is the recast EU Energy Efficiency Directive (EED): data centers with total energy consumption of 1 MW and above must use waste heat recovery or show that it is infeasible. The introduction also states that as much as 90% of the energy used by IT can be recovered as heat.

As a technical caution, cooling often consumes 20% to 30% of total data center power, and heat rejection capacity is still needed as backup even when heat is exported. Heat reuse therefore does not remove the cooling design; it adds a dependency and a further redundancy consideration.

Key points

1. Northern Europe leads with nearly 60 documented heat recovery projects.
2. The EU EED recast requires data centers with total energy consumption of 1 MW and above to use waste heat recovery or show infeasibility.
3. Published as UII Briefing Report 114, October 2023.
4. As much as 90% of the energy used by IT can be recovered as heat.
5. Around 60 projects in Europe and six in North America, with 11 more in development (per Open Compute Project).
6. Cooling often consumes 20% to 30% of total data center power.
7. Heat rejection capacity is still needed as backup when heat is exported.

Using it in design

• For EU sites of 1 MW and above, trigger the EED waste-heat assessment as a step in the design process.
• In a heat-reuse calculator, treat recoverable heat within the bound of up to 90% of IT energy.
• Keep backup heat rejection capacity in the cooling design even when heat is exported.
• Use cooling's 20-30% share of total power as an input to recovery feasibility.

Who should read it

Engineers working on sustainability, energy efficiency and cooling design, and owners of sites subject to EU rules.

Publication details

Authors

M. Smolaks

Publisher

Uptime Institute Intelligence

Year

2023

Document number

UII Briefing Report 114

Document language

English

Source type

Industry body

Access

Citation only

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation