An edge data centre on a warm loop

Northgate is two data halls with 42 and 28 kW of IT around the clock on a computer-room air handler — a deep coil and a draw-through plug fan, no outside air, the halls' return on the coil — fed by the modular chiller holding 13 °C: a warm loop of the kind TC 9.9's A1 band permits. A UPS room sits on a remote condensing unit and an indoor DX unit cut along the refrigerant lines, and a NOC on the split.

Two things the first run taught: a 90 kW-class chiller ran flat out against 50 + 35 kW of IT, and a well-mixed hall at 25 °C on 14 °C water limits the CRAH to an 18 °C supply — 73 kW against 75 — so the halls hold 26 °C (A1 allows 27) on a 13 °C loop. In winter the indoor unit's economiser holds the UPS room on outside air while the condensing unit idles.

On Singapore's year the building reads 1 003 MWh of cooling on 330 MWh of electricity, the halls held at 26 °C to within five hours after the cold-start hour.

What it reads on Singapore

What it taught

• A warm loop is a real design choice the model can price: 13 °C water, a deep coil, a hall at 26 °C.
• A refrigerant pair across two blocks runs one hour behind, like water: the indoor unit takes the feed the condensing unit reported last hour.
• Constant gains make every hour count — unmet hours around the clock, no setback, no schedule.

The machines

• Example CRAH, 8 m³/s chilled water — open in the builder
• Example air-cooled chiller, 90 kW class — open in the builder
• Example condensing unit, 12 kW class — open in the builder
• Example indoor DX unit, 12 kW class — open in the builder

Sources

• ASHRAE TC 9.9 thermal guidelines (A1 band)
• PVGIS TMY, Singapore

Readings of the shipped model on the building's own PVGIS typical meteorological year; engineering estimates from catalog data and published correlations. The building runs on every plan, including Free, a few times a day.