Cooling unit

Abstract

The invention relates to a cooling unit for storing temperature-sensitive goods at a desired cooling temperature, comprising a cooling compartment ( 9 ) for storing the temperature-sensitive goods, an insulation ( 1 ) separating the cooling compartment ( 9 ) from an ambient space ( 10 ), a multi-stage cascade refrigeration system adapted to cool down the cooling compartment ( 9 ) to the desired cooling temperature and/or maintain the desired cooling temperature in the cooling compartment ( 9 ), said multi-stage cascade refrigeration system comprising at least a high-temperature refrigeration cycle ( 11 ) and a low-temperature refrigeration cycle ( 12 ), whereas said low-temperature refrigeration cycle ( 12 ) comprises a low-temperature evaporator ( 13 ) arranged to absorb heat from the cooling compartment ( 9 ), and whereas the high-temperature refrigeration cycle ( 11 ) comprises a high-temperature condenser ( 14 ) arranged to reject heat to the ambient space ( 10 ), whereas a high-temperature evaporator ( 3 ) of the high-temperature refrigeration cycle ( 11 ) is thermally coupled to a low-temperature condenser ( 4 ) of the low-temperature refrigeration cycle ( 12 ) in order to form an intercooler, whereas said high-temperature evaporator ( 3 ) and/or said low-temperature condenser ( 4 ) are/is thermally coupled to the insulation ( 1 ).

1 - 12 . (canceled) 
     
     
         13 . A cooling unit for storing temperature-sensitive goods at a desired cooling temperature, the cooling unit comprising:
 a cooling compartment for storing the temperature-sensitive goods;   an insulation separating the cooling compartment from an ambient space;   a multi-stage cascade refrigeration system adapted to cool the cooling compartment, the multi-stage cascade refrigeration system including a high-temperature refrigeration cycle and a low-temperature refrigeration cycle, wherein:
 the low-temperature refrigeration cycle comprises a low-temperature evaporator arranged to absorb heat from the cooling compartment, and wherein the high-temperature refrigeration cycle comprises a high-temperature condenser arranged to reject heat to the ambient space, 
 a high-temperature evaporator of the high-temperature refrigeration cycle is thermally coupled to a low-temperature condenser of the low-temperature refrigeration cycle in order to form an intercooler of the high-temperature refrigeration cycle and the low-temperature refrigeration cycle, and 
 a heat exchanger selected from the group consisting of the high-temperature evaporator and the low-temperature condenser is thermally coupled to the insulation, wherein the heat exchanger is thermally coupled to the insulation by means of a heat collector, the heat collector being made of metal, wherein the heat collector is either arranged inside the insulation or in contact with a surface of the insulation, and wherein the heat collector surrounds the cooing compartment at least in sections like a wall. 
   
     
     
         14 . The cooling unit according to claim  1 , wherein the heat collector has the shape of a plate. 
     
     
         15 . The cooling unit according to claim  1 , wherein a thermally active surface of the heat collector is larger than a thermally active surface of the heat exchanger selected from the group consisting of the high-temperature evaporator and the low-temperature condenser. 
     
     
         16 . The cooling unit according to claim  1 , wherein the heat collector is thermally coupled to the heat exchanger selected from the group consisting of the high-temperature evaporator and the low-temperature condenser by means of soldering, brazing, welding, gluing, or clipping. 
     
     
         17 . The cooling unit according to claim  1 , wherein the intercooler has a tube-on-tube design, and the heat collector is thermally coupled to both the high-temperature evaporator and the low-temperature condenser. 
     
     
         18 . The cooling unit according to claim  1 , wherein the intercooler has a tube-in-tube design, and the heat collector is thermally coupled only to the high-temperature evaporator or the low-temperature condenser. 
     
     
         19 . The cooling unit according to claim  1 , wherein the insulation comprises cyclopentane foam, polyurethane foam, polystyrene, vacuum-panels, or mineral wool. 
     
     
         20 . The cooling unit according to claim  1 , wherein the multi-stage cascade refrigeration system is realised as a two-stage cascade refrigeration system comprising the high-temperature refrigeration cycle and the low-temperature refrigeration cycle. 
     
     
         21 . Cooling unit according to claim  1 , wherein the cooling unit is a portable cooling unit for transporting temperature-sensitive goods while maintaining the desired cooling temperature. 
     
     
         22 . Cooling unit according to claim  2 , wherein the heat collector is arranged in contact with an outer surface of the insulation with respect to the cooling compartment. 
     
     
         23 . Cooling unit according to claim  3 , wherein the heat collector has the shape of a flat or curved plate protruding from the heat exchanger selected from the group consisting of the high-temperature evaporator and the low-temperature condenser. 
     
     
         24 . Cooling unit according to claim  5 , wherein a thermally active surface of the heat collector is at least twice as large as a thermally active surface of the heat exchanger selected from the group consisting of the high-temperature evaporator and the low-temperature condenser.