no watt wastedHeat Network 3D
IHN heat network · a year of data-centre heat · drag to orbit, scroll to zoom
no watt wastedIHN heat network · a year of data-centre heat · drag to orbit, scroll to zoom
The data centre is a hydro-cooled compute load: almost all of the electricity it uses leaves as hot water. A plate heat exchanger passes that heat into the network through a hot tap on the main, and the existing Hoval gas boilers make up whatever the network still needs. The animation steps through a full year (1 April 2025 – 31 March 2026) half-hour by half-hour. In every case the data centre is run against the all-in half-hourly cost of electricity for that period (wholesale, losses, distribution charges, levies and capacity-market charges), with London's grid carbon intensity for each period taken from NESO's Carbon Intensity API.
| Electricity to heat | 95% of electrical input recovered as heat in the cooling water | P1 0.25 MWe → 0.24 MWth P2 2.1 MWe → 2.0 MWth (2.3 MWth at +15%) |
| Phase 2 data centre | The Phase 1 miners are redeployed into a single 2 MWth data centre on the 11 kV supply and the Phase 1 container is released for another site. It can run 15% above nameplate for extended periods and can throttle back or pause | one hall · 0 – 115% of 2.1 MWe |
| Network connection | Heat leaves the site through the new DN125 connection to the network main, which passes about 2 MWth at a 15 K drop (70 °C in, 55 °C back). When the data centre makes more than the connection can carry, the surplus goes to the store and comes back out through the connection while the data centre is paused | 2.0 MWth · ≈115 m³/h |
| Network | Phase 2 flow 70 °C, return 55 °C (Clever Energy plan; kinder to the mining chips); flow rate through the tap = heat ÷ (4.18 kJ/kg·K × 15 K) | ≈57 m³/h per MWth |
| Data centre outlet | Phase 1: 75 °C against today's 75/55 network. Phase 2: 73 °C against the recommissioned 70/55 network, which is kinder to the mining chips; plate heat exchanger with 3 K approach in both | 72 °C (P1) · 70 °C (P2) into the network side |
| Data centre loop | Small temperature rise across the miners at high flow (manufacturer guidance ≤ ~7 K), lifted to the outlet temperature in high-temperature mode | ≈68 → 75 °C (P1) · ≈66 → 73 °C (P2) |
| Boilers | Seasonal efficiency at a 55 °C return (limited condensing) | 90% |
| Gas not burned | Gas the boilers would have used to make the same heat, at gross calorific value; carbon factor for natural gas (DESNZ 2025) | 11.1 kWh/m³ · 0.183 kgCO₂/kWh |
| Operating pattern | Phase 1 runs in the cheapest 70% of half-hours of the year. Phase 2 has an annual energy budget of 65% of nameplate, placed half-hour by half-hour where the all-in cost of electricity is lowest and the heat can be used: flat out at +15% on windy nights, throttled when the connection or the network is full, paused when power is dear | P1 6,132 h · P2 ≈4,260 h at +15%, ≈1,040 h throttled, ≈3,270 h paused |
| Home equivalent | Heat delivered is also shown as the number of homes it would heat for a year, at 10 MWh of heat per home (Ofgem's typical domestic gas use of 11,500 kWh through a ~90% efficient boiler) | 10 MWh per home per year |
| Network demand | Indicative profile modelled from London temperatures (heating-degree based, with morning and evening peaks); to be replaced by metered network data | ≈1.1 – 7.1 MW · 23 GWh/yr |
| Vessels | Three horizontal foil-clad vessels — storage zones A, B and C on the plant schematic — connected in parallel between the flow and return headers and charged and discharged together | A 180 · B 90 · C 90 = 360 m³ |
| Theoretical capacity | 360 m³ × 15 K (70/55 °C) × 4.18 kJ/kg·K — a 70 °C top instead of 75 °C costs a quarter of the capacity | 6.3 MWhth |
| Usable capacity | Tall stratified stores with a strong thermocline deliver 85–95% of theoretical; horizontal vessels mix the layers more and typically 60–75%. Modelled at 70% | 4.4 MWhth |
| Heat floor | The store is never "empty": its bottom sits at the 55 °C return. Heat below return temperature cannot be delivered to a 75/55 network without a heat pump | 55 °C |
| Standby loss | Well-insulated 300–400 m³ class store | ≈1% per day |
| Charge / discharge | Charged by data-centre surplus (up to 2.5 MW); discharged to the network up to 4 MW | ≈2.2 h keeping the connection full · ≈1.1 h at the winter peak |
| Operation | Charges whenever the hall makes more heat than the network takes — windy winter nights at +15%, and summer and shoulder-month nights — and discharges through the expensive periods so the boilers stay off longer. With the connection the binding limit, the store's main job is to keep it full while the data centre pauses: it cycles rather than banks, about one and a half times a day | ≈530 cycles/yr · ≈2,300 MWh through the store · ≈600 MWh of it Nov–Mar |