Who makes heat reuse & district heating interfaces for AI data centers

Taps the facility water loop (6.05) — typically its warmer, IT-heat-carrying side — and routes it through a heat exchanger, and where the reuse temperature needs boosting, a large heat pump, into a district heating network or process-heat customer, displacing some of the heat-rejection equipment (6.02) a site would otherwise need. Adoption is concentrated where district heating networks already exist and local economics or regulation favor it, so it remains a minority design choice rather than a default. Higher-temperature liquid-cooling loops in AI racks produce warmer reject water than legacy air-cooled facilities, which is exactly the direction that makes heat reuse more thermodynamically attractive, since a heat pump has less work to do raising an already-warm source to district-heating temperature. Investors should treat this as a niche but growing interconnection market tied to specific geographies with district heating infrastructure, not a broad-based demand driver across the layer.