[banerj1s]

MCW: Main Cooling Water System. Cooling water from Open source or Cooling tower to Surface condenser often called as Circulating Water System (KKS notification PAB)

ACW: Auxiliary Cooling Water System. Cooling water Tap off from Circulating Cooling Water to Closed Cooling Exchanger and back to the Circulating Cooling water. If the head is not enough sometimes you may have a Aux Cooling Pump. (KKS notification PCB).

CCW: Closed Cooling Water System. Cooling water for various lube oil coolers as of Turbine Lube Oil Cooler, BFP Lube Oil Cooler etc and back to the Closed Cooling Water Exchanger. Always have a Close Cooling Water Pump. (KKS notification PGB).

Cheers