Patent ID: 7609519

Claim:
A coolant control unit for a liquid cooled electronics system comprising: an external coolant inlet and external coolant outlet for respectively receiving external coolant from and returning external coolant to a coolant distribution unit, the coolant distribution unit controlling at least one of temperature, pressure or cleanliness of the external coolant; an internal coolant loop for circulating coolant to the liquid cooled electronics system; a first control valve coupling the external coolant inlet to the internal coolant loop at a coolant supply location of the internal coolant loop and a second control valve coupling the external coolant outlet to the internal coolant loop at a coolant return location of the internal coolant loop; a liquid-to-air heat exchanger connected between the first control valve and the second control valve; and control logic for controlling operation of the coolant control unit in one of an external coolant mode and an internal coolant mode, wherein in the external coolant mode, the first control valve and the second control valve are controlled to allow passage of external coolant through the internal coolant loop to the liquid cooled electronics system, and in the internal coolant mode, the first control valve and second control valve are controlled to isolate coolant within the internal coolant loop from the external coolant inlet and outlet, and pass the coolant therein through the liquid-to-air heat exchanger.