CHILLER CONTROL PARAMETERS

CHILLER CONTROL PARAMETERS

1.Chilled Water Supply Temperature (CHW Supply Temp)

⇒ Setpoint usually 6–7°C.

⇒ Maintained by controlling compressor operation and refrigerant flow.

⇒ Impacts building cooling efficiency directly.

2.Chilled Water Return Temperature (CHW Return Temp)

⇒ Normally around 12–14°C from building side.

⇒ Indicates cooling load — higher return temp = higher demand.

3.Delta T (Temp Difference)

⇒ CHW Return – CHW Supply. Ideal: 6–8°C.

⇒ Lower delta T = flow too high or load too low.

⇒ Important for energy optimization and sizing.

4.Chilled Water Flow Rate

⇒ Must meet minimum flow for evaporator (to avoid freezing).

⇒ Controlled by VFD pumps, 2-way valves, or bypass lines.

⇒ Flow switch protects evaporator from dry run.

5.Evaporator Pressure & Temperature

⇒ Used to monitor refrigerant evaporation process.

⇒ Sudden drop = low refrigerant or blocked flow.

⇒ Used to trip chiller on low pressure.

6.Condenser Water Temperature (In/Out) (Water-Cooled only)

⇒ Typical: 30–37°C in / 35–42°C out.

⇒ Affects condenser pressure and overall chiller efficiency.

⇒ High condenser temp = poor cooling tower performance.

7.Refrigerant Pressure – Low Side & High Side

⇒ Low side (evaporator): for cooling.

⇒ High side (condenser): for heat rejection.

⇒ Helps detect abnormal conditions like:

Low refrigerant charge
Blockage
Overheating

8.Compressor Current (Amps)

⇒ Shows actual compressor load.

⇒ High current = heavy load or high head pressure.

⇒ Used for overload protection and energy monitoring.

9.Alarms & Trips

⇒ Low CHW flow

⇒ High condenser pressure

⇒ Low refrigerant pressure

⇒ Compressor overload

⇒ Sensor failure

10.BMS/PLC Integration Points

⇒ Start/Stop command

⇒ CHW temp setpoint override

⇒ Status feedback (Running/Fault)

⇒ Real-time monitoring of: Temps, Pressures, Flow, Alarms.

Comments

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