Data Centre Loop Studio/ one loop across two sites
Data centre heat,
reborn as factory heat.
A data centre turns almost every kWh its servers draw into warm water and pays to throw it away. A factory next door burns fuel for the same temperatures. Put heat pumps on the return water and the arithmetic below is what the loop is worth — to the factory, to the data centre, and to the carbon account of both.
₹ per kWh of useful heat
Annual cost of the factory's heat
Illustrative, not an offer. The defaults are the deck's worked example — 10 MW IT, 5 MWth at 80 °C, COP 3.5, 8,000 h — and reproduce its figures. Capex, the hydraulic interface, the tripartite heat agreement and the DC's change-control windows are outside this arithmetic; the joint baseline replaces every input with metered loop temperatures and flows.
In short/ Data Centre Loop Studio
Data Centre Loop Studio is a free calculator for the jouleWise one-loop model, in which heat pumps lift a data centre's cooling-return water into hot water and low-pressure steam for the factory next door.
Enter the IT load and PUE, the cooling-loop return temperature, the delivery temperature the factory needs, the factory's average heat demand, the fuel its boilers burn and the electricity the heat pumps would run on. The studio returns the COP at that lift, the green heat the loop can deliver, the heat-pump electricity, the factory's energy-cost saving, Scope 1 CO₂ avoided, the chiller electricity and cooling-tower water the data centre no longer spends, and the share of the data centre's heat the loop takes. The defaults reproduce the deck's worked example.
What to take away
- Each MW of IT load releases about a MW of heat into the cooling water, continuously; a 10 MW IT hall at PUE 1.4 is about 14 MW at the meter.
- The lift table from the deck: COP about 5 at 30 K lift, 3.5 at 50 K, 2.5 at 70 K; low-pressure steam to 120 °C at about 2.
- Air-cooled or chilled-water halls return the loop at 20–30 °C; liquid-cooled and AI racks return at 40–50 °C, which narrows the lift to about 35 K for 80 °C delivery and lifts the COP to about 4–4.5.
- At COP 3.5 one kWh of electricity plus 2.5 kWh from the loop gives 3.5 kWh of factory heat and 2.5 kWh of cooling the data centre no longer buys — about 6 kWh of useful heating and cooling per kWh.
- Default worked example: 10 MW IT, 5 MWth at 80 °C, 8,000 h/yr, COP 3.5, PNG boiler at ₹55/SCM and 85% efficiency, green electricity at ₹5.50/kWh: 40,000 MWh-th delivered, 11,430 MWh of electricity, 28,570 MWh-th from the loop, ₹24.9 Cr of fuel replaced by ₹6.3 Cr of electricity, about ₹18.6 Cr/yr saving before capex and O&M, about 8,800 t CO₂ avoided, up to about 5.7 GWh of chiller electricity and about 40,000 m³ of cooling-tower water saved.
What it assumes
- Illustrative, not an offer. Values are replaced with metered loop temperatures and flows in the baseline.
- The chiller credit uses a chiller COP of 5 and applies where chillers would otherwise have moved that heat; water at about 1.5 litres evaporated per kWh-th rejected applies only to wet towers.
- Green electricity is treated as zero-emission on a market basis. Capex, the hydraulic interface and the tripartite heat agreement are outside the calculator.
Questions this page answers
Why is data-centre return water such a good heat source?
Does this put the data centre's uptime at risk?
What does the factory pay?
Is this operating anywhere?
What it is telling you/ read this bit
Warmer return water,
cheaper factory heat.
Ambient air at 30 °C is a 50 K lift to 80 °C. A chilled-water hall returns at 20–30 °C — the same lift, with the bonus that heat is taken out before the chillers. A liquid-cooled or AI hall returns at 40–50 °C, which is a 35 K lift and a COP in the fours. Switch the cooling architecture and watch the COP, and everything downstream of it, move.
Each MW of IT load is about a MW of heat. At COP 3.5 that supports about 1.4 MWth of factory heat per MW of IT, so a 10 MW hall can carry a factory of about 14 MWth; ask for more and the rest stays on the boiler, which the saving already accounts for.
Heat taken from a chilled-water loop is heat the chillers no longer move, at about a fifth of the energy; heat taken from any loop is water the towers no longer evaporate, where the heat was going through wet towers. Both belong to the data centre, and both are metered at the same boundary as the heat the factory buys.
No capex, no hydraulic interface design, no change-control windows, no tripartite heat agreement. Those come out of the joint baseline — loop temperatures and flows, PUE and water data, the factory's heat map — and the design that follows it.