Thermosyphon-based refrigeration system

Abstract

A refrigeration system that is capable of using carbon dioxide as a refrigerant and makes use of an evaporator that operates as a thermosyphon insensitive to orientation. The refrigeration system includes a condenser adapted to be wrapped around and physically contact a heat sink for conducting heat from a refrigerant within the condenser to the heat sink, a first line connected to the condenser through which the refrigerant is discharged from the condenser after being condensed to a liquid state, an evaporator coupled to the first fluid line and adapted for physical contact with a body so as to draw heat from the body to vaporize the refrigerant within the evaporator, and a second fluid line connected to the evaporator and through which the refrigerant is discharged from the evaporator after being vaporized and then delivered to the condenser. At least the evaporator is formed to have a multiport tube comprising a plurality of parallel passages with hydraulic diameters of less than 0.8 mm so as to enable refrigerant to be drawn into the passages regardless of orientations of the evaporator and the evaporator multiport tube.

1 . A refrigeration system comprising: 
 a condenser configured for wrapping around and physically contacting a heat sink for conducting heat from a refrigerant within the condenser to the heat sink, the condenser comprising a condenser inlet manifold, a condenser multiport tube comprising a plurality of parallel passages in fluidic communication with the condenser inlet manifold, and a condenser outlet manifold in fluidic communication with the parallel passages;    a first line connected to the condenser outlet manifold through which the refrigerant is discharged from the condenser after being condensed to a liquid state within the condenser;    an evaporator coupled to the first fluid line and adapted for physical contact with a body for thermal communication therewith, the evaporator comprising an evaporator inlet manifold, an evaporator multiport tube comprising a plurality of parallel passages in fluidic communication with the evaporator inlet manifold, and an evaporator outlet manifold in fluidic communication with the parallel passages of the evaporator multiport tube, the evaporator drawing heat from the body to vaporize the refrigerant within the evaporator multiport tube; and    a second fluid line connected to the outlet manifold of the evaporator and through which the refrigerant is discharged from the evaporator after being vaporized within the evaporator, the second fluid line being connected to the inlet manifold of the condenser for delivering the vaporized refrigerant to the condenser;    wherein the parallel passages of at least the evaporator multiport tube have hydraulic diameters of less than 0.8 mm so as to enable the refrigerant to be drawn into the parallel passages from the evaporator inlet manifold regardless of orientations of the evaporator and the evaporator multiport tube.    
   
   
       2 . A refrigeration system according to  claim 1 , wherein the condenser has a shape causing the condenser inlet and outlet manifolds to be located adjacent each other, the condenser having a clamp that secures the condenser inlet and outlet manifolds together and clamps the condenser multiport tube around the heat sink.  
   
   
       3 . A refrigeration system according to  claim 1 , wherein the refrigerant is carbon dioxide.  
   
   
       4 . A refrigeration system according to  claim 1 , wherein the first fluid line and the second fluid line have substantially equal and constant internal diameters.  
   
   
       5 . A refrigeration system according to  claim 4 , wherein the refrigeration system is operable to draw heat from the body and conduct heat to the heat sink regardless of the flow direction of the refrigerant through the refrigeration system.  
   
   
       6 . A refrigeration system according to  claim 1 , wherein the condenser, the first fluid line, the evaporator, and the second fluid line define an internal volume of the refrigeration system that is filled with the refrigerant, and about 20 to about 40 volume percent of the internal volume is filled with the refrigerant in its liquid state.  
   
   
       7 . A refrigeration system according to  claim 1 , wherein the evaporator inlet and outlet manifolds are extruded aluminum.  
   
   
       8 . A refrigeration system according to  claim 1 , wherein the evaporator multiport tube is extruded aluminum.  
   
   
       9 . A refrigeration system according to  claim 1 , wherein the evaporator multiport tube is a flat tube containing a single row of the parallel passages.  
   
   
       10 . A refrigeration system according to  claim 1 , wherein the evaporator multiport tube is one of a plurality of serpentine evaporator multiport tubes that constitute the evaporator and through which the refrigerant flows in parallel.  
   
   
       11 . A refrigeration system according to  claim 1 , wherein each of the evaporator inlet and outlet manifolds comprises an internal channel and enhancements projecting into the internal channel to cause flow by capillary action of the refrigerant through the internal channel.  
   
   
       12 . A refrigeration system according to  claim 1 , wherein the heat sink is a heat acceptor of a Stirling engine.  
   
   
       13 . A refrigeration system according to  claim 12 , further comprising a heat exchanger coupled to the Stirling engine for conducting heat away from the Stirling engine.  
   
   
       14 . A refrigeration system according to  claim 1 , wherein the refrigeration system is mounted to a tray.  
   
   
       15 . A refrigeration system according to  claim 14 , wherein the refrigeration system and the tray are installed in a refrigeration cabinet.  
   
   
       16 . A refrigeration system comprising: 
 a heat acceptor of a Stirling engine;    a condenser wrapped around and physically contacting the heat acceptor for conducting heat from a carbon dioxide-based refrigerant within the condenser to the heat acceptor, the condenser comprising a condenser inlet manifold, a condenser multiport tube comprising a plurality of parallel passages in fluidic communication with the condenser inlet manifold, and a condenser outlet manifold in fluidic communication with the parallel passages;    a clamp securing the condenser inlet and outlet manifolds together and clamping the condenser multiport tube around the heat acceptor;    a first fluid line connected to the condenser outlet manifold through which the refrigerant is discharged from the condenser after being condensed to a liquid state within the condenser, the first fluid line having a substantially constant internal diameter;    an evaporator coupled to the first fluid line and physically contacting a body for thermal communication therewith, the evaporator comprising an evaporator inlet manifold, an evaporator multiport tube comprising a plurality of parallel passages in fluidic communication with the evaporator inlet manifold, and an evaporator outlet manifold in fluidic communication with the parallel passages of the evaporator multiport tube, the evaporator drawing heat from the body to vaporize the refrigerant within the evaporator multiport tube; and    a second fluid line connected to the outlet manifold of the evaporator and through which the refrigerant is discharged from the evaporator after being vaporized within the evaporator, the second fluid line being connected to the inlet manifold of the condenser for delivering the vaporized refrigerant to the condenser, the second fluid line having a substantially constant internal diameter that is substantially equal to the internal diameter of the first fluid line;    wherein the parallel passages of the evaporator multiport tube have hydraulic diameters of less than 0.8 mm so as to enable the refrigerant to be drawn into the parallel passages from the evaporator inlet manifold regardless of orientations of the evaporator and the evaporator multiport tube; and    wherein the substantially equal internal diameters of the first and second fluid lines enable the refrigeration system to operate regardless of the flow direction of the refrigerant through the refrigeration system.    
   
   
       17 . A refrigeration system according to  claim 16 , wherein the condenser, the first fluid line, the evaporator, and the second fluid line define an internal volume of the refrigeration system that is filled with the refrigerant, and about 20 to about 40 volume percent of the internal volume is filled with the refrigerant in its liquid state.  
   
   
       18 . A refrigeration system according to  claim 16 , wherein each of the evaporator inlet and outlet manifolds comprises an internal channel and enhancements projecting into the internal channel to cause flow by capillary action of the refrigerant through the internal channel.  
   
   
       19 . A refrigeration system according to  claim 16 , wherein the refrigeration system is mounted to a tray.  
   
   
       20 . A refrigeration system according to  claim 19 , wherein the refrigeration system and the tray are installed in a refrigeration cabinet.