A Water Cooled Chiller Plant consists of a water-cooled chiller, typically located inside the building. The plant consists of an air-cooled chiller, located outside of the building; primary and secondary pumps; expansion tank; air separator; and some form of chemical treatment. The pumps are arranged in a primary/secondary arrangement or in a variable primary pump arrangement. This device removes heat from a load and transfers it to the environment using a refrigeration system. The refrigerant vapor is used to chill process water in the evaporator and then the vapor enters the compressor of the chiller. Water Cooled Chiller Plant is very efficient.