Measure the plant, not the nameplate.
A chiller rated for excellent efficiency can still sit in a plant that performs poorly once pumps, cooling towers, part-load running and control sequences are counted. In Gulf buildings, that gap is usually the biggest energy saving available.
ESGweise audits chilled water plants and district cooling connections across the UAE and wider GCC. The ESGweise delivery team, made up of certified experts, measures plant efficiency in kW per refrigeration tonne against design, and examines part-load behaviour, delta T, approach temperatures, cooling tower performance and control sequences to find where cooling energy is being lost.
The largest load, the widest gap
In most Gulf buildings, cooling is the largest single electricity load. It is also where actual performance drifts furthest from design, because nobody re-measures the plant after commissioning.
Chillers are bought on their rated efficiency, which is measured under standard test conditions. The plant then runs at part load for most of the year, with pumps and towers that were sized for a peak day, and controls that were set up once and never revisited. Only total plant efficiency, measured in operation, shows what that costs.
Where plant efficiency is lost
- Plant kW per tonne: chillers, chilled and condenser water pumps and cooling towers together, across the load range
- Part-load operation: how chillers are staged, and how long they spend at loads where efficiency falls away
- Delta T: supply and return temperature difference against design, and the causes of low delta T syndrome
- Approach temperatures: evaporator and condenser approach, where a rising trend points to fouling or refrigerant problems
- Cooling towers: approach to wet-bulb temperature, fan control and condenser water temperature reset
- Controls: chilled water setpoint reset, pump speed control and sequencing logic in the building management system
When the plant is not yours
A building on district cooling has no chillers to audit, but it still controls how efficiently it uses the chilled water it buys. The energy transfer station is where that shows. A building returning water too cold, running a low delta T, draws more flow for the same cooling, and depending on the supply contract that can cost money as well as energy. We audit the building side of the connection: the energy transfer station, secondary pumping, valves and coils, and the controls behind them.
Logged, analysed, ranked
Design and trend review
Design data, as-built drawings and building management system trends, to establish what the plant is meant to do and what it has been doing.
Measurement campaign
Power, flow and temperature logged together across a representative operating period, including nights, weekends and changing load.
Performance analysis
Plant efficiency mapped against load and weather, with each loss traced to a cause rather than recorded as a symptom.
Measures ranked by payback
Control and setpoint changes first, because they cost least, then maintenance, then capital measures, each with savings and Scope 2 reduction stated.
Related: a full energy audit covers the rest of the site, and ISO 50001 implementation keeps the gains from drifting back.
Chiller & District Cooling Audits — questions we hear most
What is a chiller audit?
A measured assessment of how efficiently a chilled water plant produces cooling. It compares actual performance against design by logging electrical power, chilled water flow and temperatures across the plant's real operating range, then identifies why the plant uses more energy than it should: control sequences, part-load operation, fouling, pumping, or cooling tower performance.
What does kW per refrigeration tonne mean?
It is the electrical power needed to produce one refrigeration tonne of cooling, which is 3.517 kilowatts of thermal cooling. Lower is better. Coefficient of performance expresses the same thing the other way round: COP equals 3.517 divided by kW per tonne. The number that matters for a bill is total plant kW per tonne, including chillers, pumps and cooling towers, not the chiller's nameplate rating, which is measured at test conditions the plant rarely operates at.
What is low delta T syndrome?
A chilled water system designed for a certain temperature difference between supply and return that in practice runs at a much smaller one. To deliver the same cooling with a smaller temperature difference, the plant has to pump more water and often run more chillers at low load, which wastes energy. Common causes are three-way valves, poorly controlled coils and bypasses. In district cooling it matters commercially as well, because the building's energy transfer station is where a low delta T shows up against the provider's contract.
How long does chiller performance need to be measured?
Long enough to capture the plant across its real load range, which a spot reading on a hot afternoon does not. As a rule, logging should cover a representative period of normal operation including nights, weekends and changes in load, and ideally a range of outdoor conditions. Where the building management system already records reliable trend data, that history extends the picture considerably.
Thirty minutes. We figure out if there's a fit.
We don't pitch on the call. We listen, ask sharp questions, and tell you honestly whether chiller & district cooling audits is what you need — or what else might be.
Speak with our team