Data center heat reuse

A 100 MW AI campus rejects roughly 90 MW of thermal energy year-round. That's enough to heat 50,000 homes. Warm-water hydronic loops finally make that heat useful without a heat-pump stage.

Why heat reuse now

Two shifts made reuse economic: warm-water DLC pushes return water to 45–55 °C (usable directly for district heating), and the EU Energy Efficiency Directive (2023/1791) now requires new data centers above 1 MW to assess feasibility.

Who actually buys the heat

• District heating utilities — Stockholm, Helsinki, Dublin all have live projects.
• Greenhouses — 30–40 °C water is ideal for hydroponic tomato and berry operations.
• Industrial process — food, brewing, timber drying.
• Colocated housing / offices — under-floor heating loops at 35 °C.

The mechanical interface

Standard architecture: your CDU return manifold feeds a brazed-plate heat exchanger owned by the offtaker. Two isolation valves and a flow meter on your side; everything downstream is theirs. Instrument for revenue-grade heat metering (EN 1434 class 2).

Economics

Offtake prices in the EU currently sit at €10–25 per MWh of delivered heat. A 20 MW warm-water cluster running at 90% capture can generate €1.5–4 M/year in heat revenue — enough to underwrite the entire CDU capex within 3–5 years.

EU regulation

Under EED Article 26, operators must publish reuse feasibility studies for new facilities. Germany's EnEfG goes further — 10% reuse by 2026, 20% by 2028 for new sites. Design the interface even if you don't commission it on day one; retrofitting an insulated HEX skid mid-life is far more expensive.