Heat Recovery


Private AI infrastructure with optional heat recovery.

Dense AI systems produce continuous heat. We design where it goes — so that larger deployments can support building heat or hot-water preheating instead of rejecting everything outdoors.

The physics, stated plainly

Nearly all electricity a server consumes becomes heat. A system drawing 1 kW continuously emits roughly 1 kW of heat — about 24 kWh of thermal energy per day. At 20 kW, that is enough to matter for a building’s heating or hot-water preheating. Whether it is worth capturing depends on temperature, distance to the plant room, and your heat demand across the year.

  • Air-cooled exhaust is diffuse and low-grade — honest uses are room or ducted-air heating.
  • Direct liquid cooling captures heat at useful temperatures: water at 35–45 °C suits floor heating and preheating; 45–55 °C supports hot-water preheat.
  • Sanitary hot water above 60 °C requires a heat-pump booster and legionella management — a matter for licensed professionals.

When it makes sense — and when it does not

It makes sense for continuous loads of roughly 10 kW and above located near a plant room, in buildings with real heat demand: office heating, domestic hot water, wellness or pool loads, or a district-heating interface at facility scale.

It does not make sense for desktop-class systems. A small office node warms the room it stands in; we will not dress that up as heat recovery, and we do not recommend plumbing for it.

The options ladder

  1. Room and ducted-air reusesmall systems Winter heat contribution from sensible placement and ducting. No formal recovery claim.
  2. Direct liquid cooling with dry coolerdense Vault / Cell Quieter, denser, less room air-conditioning — and the foundation for real heat capture.
  3. Liquid cooling with hot-water preheatcontinuous 5–40 kW A plate heat exchanger and buffer tank feed building preheat; a dry cooler takes the excess.
  4. Heat-pump boosterwhere 55–70 °C is needed Converts server-grade heat into sanitary hot water and radiator temperatures.
  5. Facility and district interfacerack scale Metered heat into the building plant or a district network — engineered, permitted, and contracted.
Heat path from GPU servers through CDU and heat exchanger to building heat, with dry-cooler fallback GPU servers liquid-cooled CDU coolant loop Heat exchanger loops separated Buffer tank + heat pump if needed Building heat metered dry cooler — full fallback
The dry-cooler fallback is a design requirement: the computer must never depend on the building needing heat, and the building must never depend on the computer running.

Engineering first, claims second

  • A site survey precedes every proposal — heat demand, plant-room distance, tariffs, and summer dump path are measured, not assumed.
  • Heat value is computed from your displaced heating cost, and presented as a range in the proposal — never as a public promise.
  • Licensed HVAC partners execute all building work: plumbing, sanitary compliance, legionella controls, permits. ANULUM designs and coordinates.
  • We do not promise free heat, and we do not make carbon claims without lifecycle evidence.

Ask for a thermal pre-feasibility check.

The architecture review includes a heat-recovery pre-feasibility for denser systems — before any HVAC engineering is commissioned.

Request a confidential architecture review