A method and an apparatus are provided for cooling a heat source using a refrigerant flow in a heat exchanger. According to some embodiments, a flow property of the refrigerant as it flows through a heat exchanger is measured and based on the measurement a flow distribution rate for the flow of the refrigerant in the heat exchanger is determined. A valve is operated for adjusting the flow rate of the refrigerant in the heat exchanger according to the determined flow distribution rate.
STATEMENT OF GOVERNMENT INTEREST IN THE INVENTION
 This application was made with government support under Department of Energy Grant No. DE-EE0002B95. The United States government may have certain rights in the invention.