EPF HQ District Cooling: BMS Control to 0.7 kW/RT

About the project

EPF, the Employees Provident Fund, is the largest fund manager in Malaysia and the country's national retirement scheme. Its Kuala Lumpur headquarters runs every hour of the day. The cooling for it doesn't come from chillers in the building's own basement; it comes from a separate district cooling plant that makes chilled water and pipes it across to the HQ.

Cobler built the BMS for that plant. The project was led by main contractor MRCB, and our scope was the building automation: the control system that runs the chillers, pumps and cooling towers as one plant instead of a roomful of separate machines.

The number that matters: kW/RT

A chilled water plant is judged on its kW/RT, the kilowatts it burns for every tonne of cooling it puts out. Think of it as the plant's fuel economy. It lands on the bill every hour the plant runs, so a small difference compounds into a big one over a year.

Most plants sit between 0.85 and 1.0 kW/RT. The brief here was 0.7. You don't get there by dropping in one efficient chiller. The number is the sum of everything drawing power: the chillers, the pumps moving chilled water and condenser water, the cooling tower fans pushing heat out to the air. Work any of them harder than the load needs and the kW/RT drifts up. The cooling load moves all day, so holding the number takes constant adjustment. That is what the BMS does.

Chiller staging

Most of the gain comes from staging: how many chillers run at a given moment, and which ones. A chiller has a band where it is most efficient. Lightly loaded, it wastes energy. Flat out, it wastes energy. Run four chillers against a load that two could carry and all four sit in the inefficient zone; run too few and you push the ones that are on past their best point.

So the BMS watches the real cooling demand and stages to it, not to a timetable. It starts the next chiller only when the load actually needs it, and drops one the moment it does not. It also chooses which chiller leads, so the most efficient machine takes the base load and the running hours spread across the fleet. Once the chillers are right, the pumps and towers fall in behind them instead of moving water for capacity that is not even on. Keeping a wide enough gap between the supply and return water temperature, the delta-T, stops the pumps doing more work than the cooling calls for.

The result

The plant hits 0.7 kW/RT, and holds it as the load shifts through the day rather than only at the one design point on paper. EPF runs the building around the clock, so that efficiency is money saved every hour, not a one-off at handover.

CobiNeural runs on top of the plant and tracks the kW/RT live, so operators see where the plant is sitting at any moment instead of working it back from last month's bill. Want the same picture on your own plant? See our other work or book a demo.