Central air conditioning in mid- and large-size buildings is usually delivered through chilled-water systems. Understanding the basics helps managers ask the right questions and spot problems early.
How a chilled-water system works
A chiller cools water, which is then pumped through pipes to fan coil units or air handlers across the building. Air is cooled by passing over those coils. The warm water returns to the chiller and the cycle repeats.
What to monitor
- Supply and return water temperatures
- Refrigerant pressures on the chiller
- Cooling-tower water quality (if applicable)
- Pump operating hours and vibration
- Filter condition on indoor units
Common symptoms
Uneven cooling between floors usually points to balancing or air-handler issues, not the chiller itself. Rising energy consumption with stable occupancy often signals fouled coils or scale buildup. A noisy compressor deserves immediate attention.
Energy efficiency
Even small adjustments — raising chilled-water setpoints by 1°C, scheduling startups to match occupancy — can produce meaningful savings without compromising comfort.