Self-pumped cooling device

Abstract

A vapor conduit having a first cross sectional area is connected to an evaporator for refrigerant exiting the evaporator. The evaporator is connected to a reservoir by a filling conduit having a second cross sectional area. A first liquid plug is disposed in the vapor conduit and a second liquid plug is disposed in the filling conduit. A first sum of forces acting on the first liquid plug is less than a second sum of forces acting on the second liquid plug ( 56 ) causing the refrigerant to expand into the vapor conduit to a greater extent than into the filling conduit causing continuous circulation of the refrigerant in the same direction. The first cross sectional area of the vapor conduit is greater than the second cross sectional area of the filling conduit for causing the first sum of forces to be greater than the second sum of forces.

1 . A closed-looped heat exchanger assembly for cooling an electronic device comprising;
 a refrigerant for undergoing liquid-to-vapor cyclical transformations,   an evaporator attached to the electronic device for evaporating said refrigerant by transferring heat from the electronic device to said refrigerant,   a vapor conduit having a first cross sectional area defining a flow path for said refrigerant exiting said evaporator,   a reservoir for holding said refrigerant and having an inlet and an outlet,   a filling conduit having a second cross sectional area defining a flow path for said refrigerant entering said evaporator,   a first liquid plug of said refrigerant in said vapor conduit having a first sum of forces acting thereon,   a second liquid plug of said refrigerant in said filling conduit having a second sum of forces acting thereon,   said first sum of forces acting on said first liquid plug being less than said second sum of forces acting on said second liquid plug for creating a head pressure during expansion of said refrigerant causing said refrigerant to expand more into said vapor conduit than into said filling conduit during vaporization of said refrigerant for evaporating said refrigerant in said evaporator and expanding said refrigerant into said filling conduit and into said vapor conduit and condensing said refrigerant in said filling conduit and said vapor conduit causing additional refrigerant to enter said evaporator from said filling conduit causing a cyclical expansion of said refrigerant into said vapor conduit to a larger extent than into said filling conduit for continuously circulating said refrigerant in the same direction through said assembly.   
   
   
       2 . An assembly as set forth in  claim 1  wherein said first cross sectional area of said vapor conduit is greater than said second cross sectional area of said filling conduit for causing said first sum of forces acting on said first liquid plug to be less than said second sum of forces acting on said second liquid plug. 
   
   
       3 . An assembly as set forth in  claim 1  wherein F vc =[F g ] vc +[F τ ] vc +[F σ ] vc +[F e ] vc ,
 wherein [F g ] vc =ρ vc gh vc ,   wherein [F τ ] vc =πr vc l vc C fvc v vc   2 ,   wherein [F σ ] vc =2σ vc A vc /r vc  cos θ vc ,   wherein [F e ] vc =0.5ρ vc A vc K vc v vc   2 , and   wherein ρ vc  is the density of said first liquid plug, g is the gravitational constant, h vc  is the height of said reservoir above said first liquid plug, r vc  is the radius of said vapor conduit, l vc  is the length of said first liquid plug in said vapor conduit, C fvc  is the coefficient of friction between said refrigerant and said vapor conduit, v vc  is the velocity of said first liquid plug into said vapor conduit, σ vc  is the surface tension of said first liquid plug in said vapor conduit, A vc  is said first cross sectional area, cos θ vc  is a geometric factor of said first liquid plug found experimentally, and K vc  is the expansion loss coefficient for said inlet of said reservoir,
   wherein  F   fc   =[F   g ] fc   +[F   τ ] fc   +[F   σ ] fc   +[F   e ] fc , 
   wherein [F g ] fc =ρ fc gh fc ,   wherein [F τ ] fc =πr fc l fc C fv v fc   2 ,   wherein [F σ ] fc =2σ fc A fc /r fc  cos θ fc ,   wherein [F e ] fc =0.5ρ fc A fc   K   fc v fc   2 ,   wherein ρ fc  is the density of said second liquid plug, h fc  is the height of said reservoir above said second liquid plug, r fc  is the radius of said filling conduit, l fc  is the length of said second liquid plug in said filling conduit, C ffc  is the coefficient of friction between said refrigerant and said filling conduit, v fc  is the velocity of said second liquid plug into said filling conduit, σ fc  is the surface tension of said second liquid plug in said filling conduit, A fc  is said second cross sectional area, cos θ fc  is a geometric factor of said second liquid plug found experimentally, and K fc  is the expansion loss coefficient for said outlet of said reservoir.   
   
   
       4 . An assembly as set forth in  claim 3  wherein said first cross sectional area of said vapor conduit is greater than said second cross sectional area of said filling conduit for causing said first sum of forces acting on said first liquid plug to be less than said second sum of forces acting on said second liquid plug. 
   
   
       5 . An assembly as set forth in  claim 4  wherein said refrigerant defines a surface in said reservoir and said inlet of said reservoir is disposed above said surface of said refrigerant in said reservoir and said outlet of said reservoir is disposed below said surface of said refrigerant in said reservoir. 
   
   
       6 . An assembly as set forth in  claim 5  wherein said evaporator is disposed below said surface of said refrigerant in said reservoir. 
   
   
       7 . An assembly as set forth in  claim 4  including a condenser for condensing said refrigerant. 
   
   
       8 . An assembly as set forth in  claim 7  including an intermediate conduit interconnecting said inlet of said reservoir and said condenser for conveying said refrigerant from said condenser to said reservoir,
 wherein said vapor conduit defines a flow path between said evaporator and said condenser for conveying said refrigerant from said evaporator to said condenser, and   wherein said filling conduit defines a flow path between said outlet of said reservoir and said evaporator for conveying said refrigerant from said reservoir to said evaporator.   
   
   
       9 . An assembly as set forth in  claim 8  wherein said reservoir has a plurality of holes therethrough defining said filling conduit,
 wherein said vapor conduit defines a flow path about said reservoir, and   wherein said condenser is disposed about said reservoir and is axially aligned with said filling conduit and with said reservoir.   
   
   
       10 . An assembly as set forth in  claim 9  wherein said condenser and said reservoir define said filling conduit between said condenser and said reservoir, and
 wherein said inlet extends along a periphery of said reservoir.   
   
   
       11 . An assembly as set forth in  claim 9  wherein said condenser has a plurality of cavities defining said vapor conduit and said intermediate conduit. 
   
   
       12 . An assembly as set forth in  claim 11  wherein said evaporator includes a plurality of partitions to define a plurality of chambers,
 wherein each of said holes in said reservoir fluidly interconnects one of said chambers of said evaporator and said reservoir, and   wherein each of said cavities of said condenser fluidly interconnects one of said chambers of said evaporator and said reservoir.   
   
   
       13 . An assembly as set forth in  claim 7  including;
 an intermediate conduit interconnecting said outlet of said reservoir and said condenser for conveying said refrigerant from said reservoir to said condenser,   wherein said vapor conduit defines a flow path between said evaporator and said reservoir for conveying said refrigerant from said evaporator to said reservoir, and   wherein said filling conduit defines a flow path between said condenser and said evaporator for conveying said refrigerant from said condenser to said evaporator.   
   
   
       14 . An assembly as set forth in  claim 13  wherein said condenser is vertically aligned with said reservoir and with said evaporator. 
   
   
       15 . An assembly as set forth in  claim 4  including;
 a first connector having a first low conductivity and interconnecting said vapor conduit and said evaporator,   a second connector having a second low conductivity and interconnecting said filling conduit and said evaporator,   said vapor conduit being of a material having a first high conductivity,   said filling conduit being of a material having a second high conductivity,   wherein said first high conductivity of said vapor conduit is greater than said first low conductivity of said first connector of said vapor conduit for insulating said evaporator from said vapor conduit, and   wherein said second high conductivity of said filling conduit is greater than said second low conductivity of said second connector of said filling conduit for insulating said evaporator from said filling conduit.   
   
   
       16 . An assembly as set forth in  claim 4  including;
 a thermal valve interconnecting said filling conduit and said evaporator for restricting flow of said refrigerant until said refrigerant reaches a predetermined temperature,   wherein said refrigerant has a temperature, and   whereby said first liquid plug expands into said vapor conduit and said second liquid plug is stationary during startup of said system when said temperature of said refrigerant is below the predetermined temperature.   
   
   
       17 . A closed-looped heat exchanger assembly for cooling an electronic device comprising;
 a refrigerant for undergoing liquid-to-vapor cyclical transformations,   an evaporator attached to the electronic device for evaporating said refrigerant by transferring heat from the electronic device to said refrigerant,   a condenser for condensing said refrigerant,   a vapor conduit being of a material having a first high conductivity and having a first cross sectional area defining a flow path for said refrigerant exiting said evaporator,   a reservoir for holding said refrigerant and having an inlet and an outlet,   said refrigerant defining a surface in said reservoir,   said evaporator being disposed below said surface of said refrigerant in said reservoir,   said inlet of said reservoir being disposed above said surface of said refrigerant in said reservoir,   said outlet of said reservoir being disposed below said surface of said refrigerant in said reservoir,   a filling conduit being of a material having a second high conductivity and having a second cross sectional area for said refrigerant entering said evaporator, defining a flow path between said outlet of said reservoir and said evaporator for conveying said refrigerant from said reservoir to said evaporator,   a first liquid plug of said refrigerant in said vapor conduit having a first sum of forces acting thereon,   a second liquid plug of said refrigerant in said filling conduit having a second sum of forces acting thereon, and   a thermal valve interconnecting said filling conduit and said evaporator for restricting flow of said refrigerant until said refrigerant reaches a predetermined temperature,   wherein said refrigerant has a temperature,   whereby said first liquid plug expands into said vapor conduit and said second liquid plug is stationary during startup of said system when said temperature of said refrigerant is below the predetermined temperature,   said first sum of forces acting on said first liquid plug being less than said second sum of forces acting on said second liquid plug for creating a head pressure during expansion of said refrigerant causing said refrigerant to expand more into said vapor conduit than into said filling conduit during vaporization of said refrigerant for evaporating said refrigerant in said evaporator and expanding said refrigerant into said filling conduit and into said vapor conduit and condensing said refrigerant in said filling conduit and said vapor conduit causing additional refrigerant to enter said evaporator from said filling conduit causing a cyclical expansion of said refrigerant into said vapor conduit to a larger extent than into said filling conduit for continuously circulating said refrigerant in the same direction through said assembly,
   wherein  F   vc   =[F   g ] vc   +[F   τ ] vc   +[F   σ ] vc   +[F   e ] vc , 
   wherein [F g ] vc =ρ vc gh vc ,   wherein [F τ ] vc =πr vc l vc C fvc v vc   2 .   wherein [F σ ] vc =2σ vc A vc r vc  cos θ vc ,   wherein [F e ] vc =0.5ρ vc A vc K vc v vc   2 ,   wherein ρ vc  is the density of said first liquid plug, g is the gravitational constant, h vc  is the height of said reservoir above said first liquid plug, r vc  is the radius of said vapor conduit, l vc  is the length of said first liquid plug in said vapor conduit, C fvc  is the coefficient of friction between said refrigerant and said vapor conduit, v vc  is the velocity of said first liquid plug into said vapor conduit, σ vc  is the surface tension of said first liquid plug in said vapor conduit, A vc  is said first cross sectional area, cos θ vc  is a geometric factor of said first liquid plug found experimentally, and K vc  is the expansion loss coefficient for said inlet of said reservoir,
   wherein  F   fc   =[F   g ] fc   +[F   τ ] fc   +[F   σ ] fc   +[F   e ] fc , 
   wherein [F g ] fc =ρ fc gh fc ,   wherein [F τ ] fc =πr fc l fc C ffc v fc   2 .   wherein [F σ ] fc =2σ fc A fc r fc  cos θ fc ,   wherein [F e ] fc =0.5ρ fc A fc K fc v fc   2 ,   wherein ρ fc  is the density of said second liquid plug, h fr  is the height of said reservoir above said second liquid plug, r fc  is the radius of said filling conduit, l fc  is the length of said second liquid plug in said filling conduit, C ffc  is the coefficient of friction between said refrigerant and said filling conduit, v fc  is the velocity of said second liquid plug into said filling conduit, σ fc  is the surface tension of said second liquid plug in said filling conduit, A fc  is said second cross sectional area, cos θ fc  is a geometric factor of said second liquid plug found experimentally, and K fc  is the expansion loss coefficient for said outlet of said reservoir,   said first cross sectional area of said vapor conduit being greater than said second cross sectional area of said filling conduit for causing said first sum of forces acting on said first liquid plug to be less than said second sum of forces acting on said second liquid plug,   a first connector having a first low conductivity and interconnecting said vapor conduit and said evaporator,   a second connector having a second low conductivity and interconnecting said filling conduit and said evaporator,   wherein said first high conductivity of said vapor conduit is greater than said first low conductivity of said first connector of said vapor conduit for insulating said evaporator from said vapor conduit, and   wherein said second high conductivity of said filling conduit is greater than said second low conductivity of said second connector of said filling conduit for insulating said evaporator from said filling conduit.   
   
   
       18 . An assembly as set forth in  claim 17  including;
 an intermediate conduit interconnecting said inlet of said reservoir and said condenser for conveying said refrigerant from said condenser to said reservoir,   said vapor conduit defining a flow path between said evaporator and said condenser for conveying said refrigerant from said evaporator to said condenser,   said condenser and said reservoir define said vapor conduit,   wherein said vapor conduit defines a flow path about said reservoir,   said filling conduit defining a flow path between said outlet of said reservoir and said evaporator for conveying said refrigerant from said reservoir to said evaporator,   said reservoir having a plurality of holes therethrough defining said filling conduit,   said inlet of said reservoir extending along a periphery of said reservoir,   said condenser being disposed about said reservoir and being axially aligned with said filling conduit and said reservoir and having a plurality of cavities defining said vapor conduit and said intermediate conduit,   said evaporator including a plurality of partitions to define a plurality of chambers,   wherein each of said holes in said reservoir fluidly interconnects one of said chambers of said evaporator and said reservoir, and   wherein each of said cavities of said condenser fluidly interconnects one of said chambers of said evaporator and said reservoir.   
   
   
       19 . An assembly as set forth in  claim 17  including;
 an intermediate conduit interconnecting said outlet of said reservoir and said condenser for conveying said refrigerant from said reservoir to said condenser,   said vapor conduit defining a flow path between said evaporator and said reservoir for conveying said refrigerant from said evaporator to said reservoir,   said filling conduit defining a flow path between said condenser and said evaporator for conveying said refrigerant from said condenser to said evaporator,   said condenser being vertically aligned with said reservoir and with said evaporator,   wherein said vapor conduit defines a flow path between said evaporator and said reservoir,   wherein said reservoir is vertically aligned with said reservoir and said evaporator,   wherein said reservoir has a plurality of holes therethrough defining said filling conduit,   wherein said vapor conduit defines a flow path about said reservoir, and   wherein said condenser is disposed about said filling conduit and about said reservoir.   
   
   
       20 . A method of cooling an electronic device using a closed looped assembly comprising the steps of;
 transferring heat generated from the electronic device to an evaporator,   boiling refrigerant in the evaporator,   forming a first liquid plug in a vapor conduit and a second liquid plug in a filling conduit from the refrigerant,   expanding refrigerant in the evaporator into the vapor conduit and into the filling conduit,   dissipating heat from the refrigerant in the vapor conduit and filling conduit,   contracting the refrigerant from the vapor conduit and from the filling conduit into the evaporator in response to said dissipating step,   adding refrigerant from the vapor conduit into the evaporator,   applying a first sum of forces to the first liquid plug and applying a second sum of forces to the second liquid plug greater than the first sum of forces during said expanding step for expanding refrigerant into the vapor conduit more than into the filling conduit.   
   
   
       21 . A method as set forth in  claim 20  including the step of repeating said steps of boiling, expanding, dissipating and contracting in response to said adding step for continuously circulating the liquid plugs in the same direction. 
   
   
       22 . A method as set forth in  claim 21  wherein F vc =[F g ] vc +[F τ ] vc +[F σ ] vc +[F e ] vc ,
 wherein [F g ] vc =ρ vc gh vc ,   wherein [F τ ] vc =πr vc l vc C fvc v vc   2 .   wherein [F σ ] vc =2σ vc A vc r vc  cos θ vc ,   wherein [F e ] vc =0.5ρ vc A vc K vc v vc   2 ,   wherein ρ vc  is the density of the first liquid plug, h vc  is the height of the reservoir above the first liquid plug, r vc  is the radius of the vapor conduit, l vc  is the length of the first liquid plug in the vapor conduit traveled by the first liquid plug, C fvc  is the coefficient of friction between the refrigerant and the vapor conduit, v vc  is the velocity of the first liquid plug into the vapor conduit, σ vc  is the surface tension of the first liquid plug in the vapor conduit, A vc  is the first cross sectional area, cos θ vc  is a geometric factor of the first liquid plug found experimentally, and K vc  is the expansion loss coefficient for the inlet of the reservoir,
   wherein  F   fc   =[F   g ] fc   +[F   τ ] fc   +[F   σ ] fc   +[F   e ] fc , 
   wherein [F g ] fc =ρ fc gh fc ,   wherein [F τ ] fc =πr fc l fc C ffc v fc   2 .   wherein [F σ ] fc =2σ fc A fc r fc  cos θ fc ,   wherein [F e ] fc =0.5ρ fc A fc K fc v fc   2 ,   wherein ρ fc  is the density of the second liquid plug, g is the gravitational constant, h fc  is the height of the reservoir above the second liquid plug, r fc  is the radius of the filling conduit, l fc  is the length of second liquid plug in the filling conduit, C ffc  is the coefficient of friction between the refrigerant and the filling conduit, v fc  is the velocity of the second liquid plug into the filling conduit, σ fc  is the surface tension of the second liquid plug in the filling conduit, A fc  is the second cross sectional area, cos θ fc  is a geometric factor of the second liquid plug found experimentally, and K fc  is the expansion loss coefficient for the outlet of the reservoir.   
   
   
       23 . A method as set forth in  claim 22  wherein said applying steps are further defined by forming the first plug in the vapor conduit with a first cross sectional area and forming the second plug in the filling conduit with a second cross sectional area less than the first cross sectional area.