Data centres, heat reuse and the future of circular energy systems
Arup · John Bynum, Nanuk Rennert et al.
Arup insight arguing that data centre waste heat should be treated as a continuous, weather-independent energy resource for district heating, industry and agriculture.
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Overview
This 2026 Arup piece (authors John Bynum, Nanuk Rennert, David Davies and Paolo Cresci) argues that data centre waste heat should be treated as a continuous, weather-independent energy resource for district heating, industry and agriculture. Roughly 90-95% of the electricity consumed by IT and cooling ends up as heat that could in principle be recovered. German data centres alone produce more than 13 TWh/yr of heat (an IRENA figure is cited).
The article explains how liquid and direct-to-chip cooling plus heat pumps raise heat quality for export through closed water loops. Heat recovery improves ERF directly and can also improve PUE (less heat for the central plant to reject) and WUE (less evaporative cooling). Operating projects in Ireland, the US, France and Japan are cited: AWS Dublin has covered 92% of the heat demand of TU Dublin's Tallaght campus since 2023, and Equinix Paris heats about 1,000 homes. The German AwaNetz programme for heat networks is also mentioned.
Some regions are starting to mandate a minimum share of heat recovery; EU planning and district-heating rules are drivers. The main lesson is to evaluate heat export during feasibility and embed it in concept design rather than retrofit it; owner and off-taker must share infrastructure risk. The source is a consultancy insight, not a technical standard. Related documents are ISO/IEC 30134-6 (ERF) and the EU Energy Efficiency Directive (EU) 2023/1791.
Key points
- Roughly 90-95% of electricity consumed by IT and cooling ends up as heat that could in principle be recovered.
- German data centres alone produce more than 13 TWh/yr of heat (IRENA figure cited).
- AWS Dublin has covered 92% of the heat demand of TU Dublin's Tallaght campus since 2023; Equinix Paris heats about 1,000 homes.
- Heat recovery improves ERF directly and can also improve PUE (less heat to reject) and WUE (less evaporative cooling).
- Some regions are starting to mandate a minimum share of heat recovery; EU planning and district-heating rules are drivers.
- Liquid and direct-to-chip cooling plus heat pumps raise heat quality for export.
- Evaluate heat export during feasibility and embed it in concept design; owner and off-taker must share infrastructure risk.
- The German AwaNetz heat-network programme is among the examples.
Using it in design
- Add a heat-recovery block to the cooling design: recoverable heat (kW, % of IT load), supply/return temperatures and optional heat-pump lift.
- Report ERF alongside PUE and WUE.
- Prompt users early in site setup when a district heating network or mandate exists nearby.
- Evaluate heat export at feasibility and fix it into concept design rather than retrofitting.
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Who should read it
Engineers working on sustainability and cooling design, site developers and decision makers assessing heat recovery at feasibility.
Related standards
- ISO/IEC 30134-6 (ERF)
- EU Energy Efficiency Directive (EU) 2023/1791
Publication details
- Authors
- John Bynum; Nanuk Rennert; David Davies; Paolo Cresci
- Publisher
- Arup
- Year
- 2026
- Document language
- English
- Source type
- Expert / community
- Access
- Free to read
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Citation
John Bynum; Nanuk Rennert; David Davies; Paolo Cresci (2026). Data centres, heat reuse and the future of circular energy systems. Arup. https://www.arup.com/insights/data-centres-heat-reuse-and-the-future-of-circular-energy-systems/
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Related sources
All sources on this topic
Energies (MDPI AG) 2026
Smart Reuse of Waste Heat from Data Centres: Energy and Exergy Analysis for a District-Heating Network in Bulgaria
Set data-centre setpoints (air temperature, free-cooling threshold) together with waste-heat sales: warmer setpoints and more free cooling cut cooling electricity by about 45% but also cut recoverable heat to about 45%.
- Centralised DH heat pumps are cited as giving COP 3-5 for supply temperatures up to 70-80 °C.
Open Compute Project Foundation 2026
Guidelines: Impact of Strategies on Data Center Energy Consumption, Carbon Footprint, and Water Consumption (March 2026)
Evaluate cooling and siting options on energy, carbon, site water and water scarcity together, not on PUE or WUE alone.
- Same example: emissions fall from 3,500 to 2,700 t CO2/yr with the carbon factor of 0.26 kg CO2/kWh.
Buildings (MDPI AG) 2025
Energy Performance Study of a Data Center Combined Cooling System Integrated with Heat Storage and Waste Heat Recovery System
Assess heat recovery from chilled-water return with a water-source heat pump and hot-water storage in annual-hour simulation; match the winter and summer outlet temperature difference (45 and 30 °C) to the user's need.
- Free natural-resource cooling covers about 28% of the cooling demand.
European Commission JRC 2025
2025 Best Practice Guidelines for the EU Code of Conduct on Data Centre Energy Efficiency (JRC141521, EUR 40267)
Design the facility to operate within the ASHRAE Class A2 allowable range and require A2 operation within warranty in IT procurement; plan separate environmental zones (practice 5.3.4) for legacy equipment.
- IT equipment AC/DC power converters should be rated at 90% efficiency or better across expected load ranges.
Open Compute Project Foundation 2025
Reference Designs for Data Center Heat Reuse, Revision 1.0
Provide a heat-recovery-station block in the site layout with space sized from capacity (plate HX footprint, 10 m2 per MW for heat pumps, about 43 m3 per MW per 30 minutes of storage) and a demarcation boundary to the heat host.
- ORC heat-to-power converts less than 4% of the heat to electricity at these low temperatures.
European Commission 2024
Commission Recommendation (EU) 2024/2395 of 2 September 2024 setting out guidelines for the interpretation of Article 26 of Directive (EU) 2023/1791 as regards heating and cooling supply requirements
When testing the 1 MW waste heat threshold, compute "total rated energy input" from rated capacity (for example utility connection or rated IT plus infrastructure), not modelled annual energy, and take the measurement point at the handover of electricity supply.
- CBA thresholds: thermal electricity generation 10 MW, industrial installation 8 MW, service facility 7 MW, data centre 1 MW.