Refrigerating Circuit And Method Of Selectively Cooling Or Defrosting An Evaporator Thereof

Abstract

A Refrigerating circuit according to the invention comprises a compressor, a condenser/gas cooler, an expansion device ( 2 ), an evaporator ( 4 ), and refrigerant conduits circulating a refrigerant therethrough. The evaporator ( 4 ) comprises refrigerant piping comprising a plurality of substantially horizontal layers ( 8, 10 ) each layer comprising a plurality of pipes ( 8 a - 8 h , 10 a - 10 h ) the pipes being substantially perpendicular to an air flow direction ( 12 ) from an air inlet region to an air outlet region of the evaporator ( 4 ). A pipe selected from the group of the second pipe ( 8 b ) to the last but one pipe ( 8 g ) in the bottom layer ( 8 ) forms the entry pipe ( 8 c ) of the evaporator ( 4 ). The entry pipe ( 8 c ) is connectable with the expansion device ( 2 ) to provide a refrigerating mode, and the entry pipe ( 8 c ) is connectable with a hot gas conduit ( 6 ) to provide a defrosting mode for the evaporator ( 4 ).

1 - 16 . (canceled) 
     
     
         17 . Refrigerating circuit comprising a compressor, a condenser/gas cooler, an expansion device, an evaporator, and refrigerant conduits circulating a refrigerant therethrough,
 wherein the evaporator comprises refrigerant piping comprising a plurality of substantially horizontal layers each layer comprising a plurality of pipes the pipes being substantially perpendicular to an air flow direction from an air inlet region to an air outlet region of the evaporator,   wherein a pipe selected from the group of the second pipe to the last but one pipe in the bottom layer forms the entry pipe of the evaporator,   wherein the entry pipe is connectable with the expansion device to provide a refrigerating mode,   wherein the entry pipe is connectable with a hot gas conduit to provide a defrosting mode for the evaporator, and   wherein a first section of the refrigerant piping of the evaporator comprises the entry pipe and the pipes on the bottom layer that are downstream of the entry pipe with regard to the air flow direction.   
     
     
         18 . Refrigerating circuit according to  claim 17 , wherein the hot gas conduit is a by-pass conduit originating between the compressor and the expansion device and ending between the expansion device and the evaporator. 
     
     
         19 . Refrigerating circuit according to  claim 17 , wherein the refrigerant entry pipe is a pipe in the first half of the evaporator in the air flow direction. 
     
     
         20 . Refrigerating circuit according to  claim 17 , wherein first connection elements connect respective adjacent pipes of the first section of the refrigerant piping of the evaporator, such that in operation the refrigerant flows in a co-flow relationship with the air flow direction in the first connection elements. 
     
     
         21 . Refrigerating circuit according to  claim 17 , wherein a second section of the refrigerant piping of the evaporator comprises the pipes on the level of and downstream from the entry pipe with regard to the air flow direction above the bottom layer. 
     
     
         22 . Refrigerating circuit according to  claim 21 , wherein second connection elements connect the pipes of the second section of the refrigerant piping of the evaporator, such that in operation the refrigerant flows in an overall counter-flow relationship with the air flow direction in the second connection elements. 
     
     
         23 . Refrigerating circuit according to  claim 17 , wherein the first pipe in the air flow direction in the bottom layer is an exit pipe. 
     
     
         24 . Refrigerating circuit according to  claim 21 , wherein a third section of the refrigerant piping of the evaporator comprises the pipes upstream of the refrigerant entry pipe with regard to the air flow direction. 
     
     
         25 . Refrigerating circuit according to  claim 17 , wherein the refrigerant piping of the evaporator comprises 2 or 3 layers. 
     
     
         26 . Refrigerating circuit according to  claim 17 , wherein each layer of the refrigerant piping of the evaporator comprises 5 to 10 pipes, particularly 6 to 8 pipes. 
     
     
         27 . Refrigerating circuit according to  claim 17 , wherein the refrigerant entry pipe is the second or third pipe in the air flow direction in the bottom layer of the refrigerant piping of the evaporator. 
     
     
         28 . Refrigerating circuit according to  claim 17 , wherein the refrigerant is 
     
     
         29 . Refrigerating circuit according to  claim 17 , wherein the air flow in the evaporator is in the refrigerating mode cooled down to a temperature below 0° C. 
     
     
         30 . Refrigerating circuit according to  claim 17 , wherein the refrigerating circuit comprises two expansion devices and two evaporators, a first expansion device and a first evaporator forming a below 0° C. refrigerating portion of the refrigerating circuit, the second expansion device and the second evaporator forming an above 0° C. refrigerating portion of the refrigerating circuit. 
     
     
         31 . Method of selectively cooling or defrosting an evaporator of a refrigerating circuit, the method comprising:
 compressing a refrigerant,   flowing the refrigerant through a gas cooler/condenser and an expansion device, when cooling is selected, or flowing the refrigerant through a hot gas by-pass conduit, when defrosting is selected,   flowing the refrigerant through refrigerant piping of the evaporator, the refrigerant piping comprising a plurality of substantially horizontal layers each layer comprising a plurality of pipes, and   flowing air through the evaporator with the air flow direction being substantially perpendicular to the orientation of the pipes,   wherein the refrigerant enters the refrigerant piping of the evaporator at a pipe of the group from the second pipe to the last but one pipe in the bottom layer, and   wherein the refrigerant flows through a first section of the refrigerant piping of the evaporator comprising the entry pipe and the pipes on the bottom layer that are downstream of the entry pipe with regard to the air flow direction.