Patent ID: 7658079

Claim:
A system for cooling one or more parts of a building or processes comprising: a compressor, a condenser having an inlet and an outlet and a plurality of condenser cooling fans, a receiver, a liquid refrigerant pump, an expansion device, an evaporator, the evaporator being surrounded by a chiller barrel having a cooled water return and a chilled water supply line, and refrigerant line means interconnecting the compressor, condenser, expansion device and evaporator in series, in a closed loop for circulating refrigerant therethrough; a compressor input line ball valve and a compressor discharge line ball valve; a compressor bypass line for the refrigerant to bypass the compressor input line ball valve, the compressor and the compressor discharge line ball valve, the compressor bypass line having a compressor bypass line ball valve; an expansion device ball valve preceding the expansion device; a expansion device bypass line for the refrigerant to bypass the expansion device and the expansion device ball valve, the expansion device bypass line having an expansion device bypass ball valve; a compressor crank case heater; a controller in electronic communication with the ball valves, the controller being capable of switching between free cooling and mechanical cooling modes when desired and floating the head pressure during mechanical cooling modes, the controller also being capable of varying the flow of liquid refrigerant in the free cooling mode; wherein the controller is capable of switching to mechanical cooling, when required, via electronic communication to turn on the compressor crankcase heater, close the expansion device bypass ball valve; open the expansion device line ball valve; start the condenser fans; wait an adjustable predetermined time for refrigerant in the evaporator to boil off; open the compressor input ball valve and the compressor discharge ball valve; close the compressor bypass ball valve; start the compressor; wait an adjustable predetermined time; and soft start the liquid refrigerant pump.