Compact refrigeration system

Abstract

A selectively controllable valve is arranged in a refrigeration circuit which interconnects the evaporator and the condenser and is controlled so that a pressure differentials built up across the valve. The valve is selectively opened to allow “batches” of working fluid to pass therethrough. In some embodiments, the working fluid which is allowed to pass through the valve, is heated in a chamber to increase the amount of pressure on the downstream of the valve. This produces expanded pressure on the downstream side of the valve. This produces expanded pressurized working fluid which increases the pressure in the condenser and forces previously condensed and liquefied working fluid through a flow restricting transfer device into an evaporator. Condensation of the just heated gas in the condenser subsequently reduces the pressure on the downstream side of the valve and establishes conditions suitable for the passage of a further amount of gaseous working fluid while itself becoming liquid to be forced through the flow restricting transfer device. Quick repetition of these cycles establishes a dynamic flow conditions and maintains the flow of liquefied working fluid into the evaporator. In other embodiments, the pressure differential is produced and/or augmented by pump such as a piston pump, or a combination of the pump and the heating chamber. If sufficient condensation can be induced using the operation of the condenser or by some other means and the required pressure differential developed, then both the heater and the pump can, depending on the circumstance and the cooling capacity that is required, be omitted. The flow of liquid working fluid from the condenser is transferred to the evaporator via either a capillary tube or a selectively controllable valve arrangement which can also posses pumping characteristics if so desired.

What is claimed is:  
     
         1 . A refrigeration system using working fluid in a closed-loop circuit, comprising: 
 a condenser;    an evaporator;    a pump to induce working fluid to flow from the evaporator to the condenser, where the pump produces a pressure differential;    a working fluid transfer device downstream of the condenser and fluidly connecting to the evaporator; and    a flow control valve operatively disposed between the downstream end of the evaporator and the upstream end of the condenser, wherein the flow control valve is responsive to at least one of a first pressure sensor disposed upstream of the flow control valve and a second pressure sensor disposed downstream of the flow control valve, and the flow control valve being constructed and arranged to selectively control the timing of the flow interruption so as to occur a plurality of times per second.    
     
     
         2 . A refrigeration system in  claim 1 , further comprising: 
 a control circuit operatively connected to the flow control valve, the pump, the condenser, the first pressure sensor, and the second pressure sensor.    
     
     
         3 . A refrigeration system in  claim 1  further comprising: 
 a dryer which is fluidly interposed between the working fluid transfer device and the condenser for removing predetermined contaminants from the working fluid.  
 
     
     
         4 . A refrigeration system in  claim 1 , wherein the working fluid transfer device which fluidly connects the condenser and the evaporator, comprises a selectively operable valve having a variable orifice for controlling the amount of working fluid which is permitted to be released into the evaporator.  
     
     
         5 . A refrigeration system in  claim 1 , the pump is adapted to selectively pump fluid therethrough in a timed relationship with the opening of the flow control device.  
     
     
         6 . A refrigeration system using working fluid in a closed-loop circuit, comprising: 
 a condenser;    an evaporator;    a pump to induce working fluid to flow from the evaporator to the condenser, where the pump produces a pressure differential;    a working fluid transfer device downstream of the condenser and fluidly connecting to the evaporator by a capillary tube; and    a flow control device operatively disposed between the downstream end of the evaporator and the upstream end of the condenser for selectively interrupting the flow of gaseous working fluid therebetween in a timed relationship with the rate of condensation of working fluid in the condenser so as to maintain a pressure differential across the working fluid transfer device to force liquefied working fluid to the evaporator.    
     
     
         7 . A refrigeration system in  claim 6  further comprising: 
 a dryer which is fluidly interposed between the working fluid transfer device and the condenser for removing predetermined contaminants from the working fluid.  
 
     
     
         8 . A refrigeration system in  claim 6 , the pump is adapted to selectively pump fluid therethrough in a timed relationship with the opening of the flow control device.