HVAC engineers

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 pressu...

  CHILLER WORKING PRINCIPLE – SIMPLIFIED A chiller removes heat from water to produce chilled water for air conditioning. It works on the refrigeration cycle — just like your fridge, but bigger and more complex. Step-by-Step Process: 1. Evaporator  → Warm return water from the building enters the evaporator.  → The refrigerant absorbs this heat and evaporates.  → Now you get chilled water (~6–7°C) sent back to AHUs/FCUs.  2. Compressor  → Vaporized refrigerant is compressed, increasing its pressure and temperature.  → This step consumes the most power. 3. Condenser  → The hot, high-pressure refrigerant releases heat to air (in air-cooled) or water (in water-cooled).  → The refrigerant condenses back into liquid. 4. Expansion Valve  → The liquid refrigerant passes through an expansion valve.  → Pressure drops, temperature drops.  → It’s now ready to absorb heat again in the evaporator. This cycle repeats continuously.