Cooling technique

Abstract

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.

What is claimed is: 
     
         1 . A method of cooling a heat source using a refrigerant flow in a heat exchanger, comprising:
 measuring a value corresponding to a property of said refrigerant flow indicative of an amount of heat being removed by said heat exchanger;   determining a flow rate of the refrigerant in the heat exchanger using said value; and   operating a valve to adjust said flow rate of said refrigerant in said heat exchanger according to said determined value.   
     
     
         2 . The method as recited in  claim 1 , wherein said measuring comprises measuring at least one parameter relative to said heat exchanger and selected from a group consisting of:
 pressure,   temperature,   capacitance,   thermal conductance,   scattering of light,   ultrasonic response,   infrared image,   visible image,   mass flow, and   power consumption.   
     
     
         3 . The method as recited in  claim 1  wherein said measuring comprises measuring a temperature difference across a reference element located between said heat source and said heat exchanger. 
     
     
         4 . The method as recited in  claim 1  wherein a flow property value is determined by measuring a first differential pressure at a first location upstream of said heat exchanger and a second differential pressure measured at a second location downstream of said heat exchanger and determining a ratio between said second differential pressure and said first differential pressure. 
     
     
         5 . The method as recited in  claim 1  further comprising maintaining a refrigerant flow rate in a branch of said heat exchanger higher than an optimum flow rate, said optimum flow rate being a flow rate at which a heat load present in said branch is a heat load required to vaporize an entirety of said refrigerant without superheat. 
     
     
         6 . An apparatus comprising a heat exchanger configured to cool a heat source using a refrigerant, comprising:
 a flow property meter configured to measure a value corresponding to a property of a flow of said refrigerant;   a processing unit coupled to said flow property meter and configured to determine a flow distribution rate for said flow of said refrigerant in said heat exchanger using said value; and   a valve coupled to said processing unit and configured to adjust a flow rate of said refrigerant in said heat exchanger according to said determined flow distribution rate.   
     
     
         7 . The apparatus as recited in  claim 6 , further comprising a control unit coupled to and configured to control an operation of said valve. 
     
     
         8 . The apparatus as recited in  claim 6 , further comprising a plurality of heat exchangers associated with respective heat sources comprised in a cooling cycle network. 
     
     
         9 . The apparatus as recited in  claim 6 , further comprising a pump configured to pump refrigerant through said heat exchanger. 
     
     
         10 . The apparatus as recited in  claim 8  wherein the cooling cycle network comprises a plurality of branches, wherein a branch includes:
 at least one heat exchanger; 
 a flow property meter; and 
 a valve. 
 
     
     
         11 . The apparatus as recited in  claim 11 , further comprising a valve configured to adjust a flow of said refrigerant in more than one individual branch in said network. 
     
     
         12 . The apparatus as recited in  claim 10  wherein said flow property meter is configured to measure a capacitance of a volume of said refrigerant in a refrigerant conduit. 
     
     
         13 . The apparatus as recited in  claim 10  wherein said flow property meter is configured to measure a pressure within a volume of said refrigerant in a refrigerant conduit. 
     
     
         14 . The apparatus as recited in  claim 10  wherein said flow property meter is configured to measure a thermal conductance within a volume of said refrigerant in a refrigerant conduit. 
     
     
         15 . The apparatus as recited in  claim 10  wherein said flow property meter is configured to measure a scattering of light within a volume of said refrigerant in a refrigerant conduit. 
     
     
         16 . The apparatus as recited in  claim 10  wherein said flow property meter is configured measure an ultrasonic response within a volume of said refrigerant in a refrigerant conduit. 
     
     
         17 . The apparatus as recited in  claim 10  wherein the flow property meter is configured to measure an infrared or visible image response within a volume of said refrigerant in a refrigerant conduit. 
     
     
         18 . The apparatus as recited in  claim 10  wherein said flow property meter is configured to measure a vapor or void fraction of said the refrigerant within a volume of said refrigerant in a refrigerant conduit. 
     
     
         19 . The apparatus as recited in  claim 6  wherein said flow property meter comprises a first differential pressure meter configured to measure a differential pressure at a location upstream a flow of said refrigerant relative to said heat exchanger and a second differential pressure meter configured to measure a differential pressure at a location downstream said flow of said refrigerant relative to said heat exchanger. 
     
     
         20 . The apparatus as recited in  claim 6  wherein said apparatus is configured to maintain a refrigerant flow rate in a branch of said heat exchanger higher than an optimum flow rate, said optimum flow rate being a flow rate at which a heat load present in said branch is a heat load required to vaporize an entirety of said refrigerant without superheat.