heat transfer system and method

Abstract

A heat transfer system and method for maintaining or controlling a temperature of a device under test (DUT) with heat generating capability. The heat transfer system comprises a temperature control unit (TCU) for thermal coupling to the DUT, the TCU arranged for flow of a heat transfer medium therethrough; an automatic expansion valve disposed upstream of the TCU; a flow-regulating valve disposed downstream of the TCU; and a controller coupled to the TCU for receiving an input signal representative of a temperature of the DUT; wherein the controller is further coupled to the flow-regulating valve to change a flow area of the flow-regulating valve based on the signal representative of the temperature of the DUT.

1 - 14 . (canceled) 
     
     
         15 . A heat transfer system for maintaining or controlling a temperature of a device under test (DUT) with heat generating capability, the heat transfer system comprising:
 a temperature control unit (TCU) for thermal coupling to the DUT, the TCU arranged for flow of a heat transfer medium therethrough;   an automatic expansion valve disposed upstream of the TCU;   a flow-regulating valve disposed downstream of the TCU; and   a controller coupled to the TCU for receiving an input signal representative of a temperature of the DUT;   wherein the controller is further coupled to the flow-regulating valve to change a flow area of the flow-regulating valve based on the signal representative of the temperature of the DUT.   
     
     
         16 . The system as claimed in  claim 15 , wherein a predetermined downstream pressure of the automatic expansion valve is adjustable by adjusting a pressure differential across the automatic expansion valve for changing a range of a cooling capacity adjustment of the heat transfer system. 
     
     
         17 . The system as claimed in  claim 16 , further comprising a receiver reservoir upstream from the automatic expansion valve for maintaining a substantially constant pressure upstream of the automatic expansion valve. 
     
     
         18 . The system as claimed in  claim 15 , comprising a plurality of TCUs, each TCU in fluid connection with one associated upstream automatic expansion valve and one associated downstream flow-regulating valve, the TCUs coupled to a single variable speed compressor, wherein the controller is coupled to each of the TCUs and to each of the flow-regulating valves for changing the flow areas of the respective flow-regulating valves based on signals representative of the temperatures of respective DUTs. 
     
     
         19 . The system as claimed in  claim 18 , further comprising an accumulator in fluid connection with each of the flow-regulating valves at an input of the accumulator, and to the compressor for the heat transfer medium at an output of the accumulator, for de-coupling the flow-regulating valves from the compressor. 
     
     
         20 . The system as claimed in  claim 18 , wherein the controller is further coupled to the accumulator for receiving a signal representative of a pressure in the accumulator, and the controller is further coupled to the compressor for adjusting a speed of the compressor based on the signal representative of the pressure in the accumulator. 
     
     
         21 . The system as claimed in  claim 15 , further comprising a condenser for dissipating heat from the heat transfer medium. 
     
     
         22 . The system as claimed in  claim 15 , wherein the controller further comprises a set-point adjustment unit for adjusting a set-point of the DUT. 
     
     
         23 . The system as claimed  claim 22 , wherein the controller changes the flow area of the flow-regulating device based on a comparison of the signal representative of the temperature of the DUT and the set-point. 
     
     
         24 . The system as claimed in  claim 23 , wherein, in an active operation mode, the set-point is changed whereby a cooling capacity of the heat transfer system is changed as a result of said comparison, resulting in a change of the temperature of the DUT. 
     
     
         25 . A method of heat transfer for maintaining or controlling a temperature of a device under test (DUT) with heat generating capability, the method comprising the steps of:
 thermally coupling a temperature control unit (TCU) to the DUT, the TCU arranged for flow of a heat transfer medium therethrough;   disposing an automatic expansion valve upstream of the TCU;   disposing a flow-regulating valve downstream of the TCU;   receiving an input signal representative of a temperature of the DUT; and   changing a flow area of the flow-regulating valve based on the signal representative of the temperature of the DUT.   
     
     
         26 . The method as claimed in  claim 25 , wherein a predetermined downstream pressure of the automatic expansion valve is adjusted by adjusting a pressure differential across the automatic expansion valve for changing a range of a cooling capacity adjustment of the heat transfer system. 
     
     
         27 . The method as claimed in  claim 26 , further comprising maintaining a substantially constant pressure upstream of the automatic expansion valve. 
     
     
         28 . The method as claimed in  claim 25 , comprising providing a plurality of TCUs, each TCU in fluid connection with one associated upstream automatic expansion valve and one associated downstream flow-regulating valve, coupling the TCUs to a single variable speed compressor, wherein the controller is coupled to each of the TCUs and to each of the flow-regulating valves for changing the flow areas of the respective flow-regulating valves based on signals representative of the temperatures of respective DUTs.