Cooling Device

Abstract

Provided is an inexpensive and compact cooling device which does not increase the circulation resistance of a refrigerant, filling quantity of a refrigerant in a natural circulation circuit wherein natural convection of the refrigerant is caused by using a thermo-siphon, and cross-sectional areas of individual passages while maintaining a desired cooling efficiency in the circuit. A secondary cooling device ( 40 ) includes a secondary heat exchange section ( 42 ) of a cascade heat exchanger (HE) which liquifies a gaseous-phase secondary refrigerant, and an evaporator (EP) which vaporizes a liquid-phase secondary refrigerant. The secondary cooling device ( 40 ) is provided with a plurality of natural circulation circuits ( 48 ) equipped with liquid pipings ( 44 ) and gas pipings ( 46 ) which connect the secondary heat exchange section ( 42 ) and the evaporator (EP). The evaporator (EP) has evaporation passages ( 52 ) of the natural circulation circuits ( 48 ) provided in layers vertically apart from one another. The evaporation passage ( 52 ) is formed by a spiral fin tube type heat exchanger whose fins are spirally wound on the outer circumference of an evaporation pipe through which the secondary refrigerant circulates.

1 . A cooling device comprising a heat exchange section ( 42 ) which condenses an evaporated refrigerant circulating through a condensation passage ( 50 ) into a liquefied refrigerant, a tubular evaporation pipe ( 56 ) disposed under the heat exchange section ( 42 ) to evaporate a liquefied refrigerant circulating through an internal evaporation passage ( 52 ) into an evaporated refrigerant, and a natural circulation circuit ( 48 ) which causes the liquefied refrigerant to flow down to the evaporation passage ( 52 ) from the condensation passage ( 50 ) of the heat exchange section ( 42 ) via a liquid piping ( 44 ), and causes the evaporated refrigerant to flow to the condensation passage ( 50 ) of the heat exchange section ( 42 ) from the evaporation passage ( 52 ) via a gas piping ( 46 ),
 wherein the cooling device comprises:   a plurality of mutually-independent natural circulation circuits ( 48 ) and an evaporator (EP) comprising a set of evaporation pipes ( 56 ) of the plurality of natural circulation circuits ( 48 ), carbon dioxide being used as a refrigerant which circulates through each natural circulation circuit ( 48 ), and   wherein   the each evaporation pipe ( 56 ) is formed bent in a meandering manner in such a way that a straight portion ( 56   a ) extends in a transverse direction intersecting a flow direction of air which circulates the evaporation pipes ( 56 ),   the liquid piping ( 44 ) is connected to a part of the evaporation pipe ( 56 ) which is downstream of the flow direction of air, and the gas piping ( 46 ) is connected to a part of the evaporation pipe ( 56 ) which is upstream of the flow direction of air, and   the plurality of evaporation pipes ( 56 ) are disposed in layers apart from one another in up and down relation.   
     
     
         2 . A cooling device comprising a heat exchange section ( 42 ) which condenses an evaporated refrigerant circulating through a condensation passage ( 50 ) into a liquefied refrigerant, and a tubular evaporation pipe ( 56 ) disposed under the heat exchange section  02 ) to evaporate a liquefied refrigerant circulating through an evaporation passage ( 52 ) into an evaporated refrigerant, and a natural circulation circuit ( 62 ) which causes the liquefied refrigerant to flow down to the evaporation passage ( 52 ) from the condensation passage ( 50 ) of the heat exchange section ( 42 ) via a liquid piping ( 44 ), and causes the evaporated refrigerant to flow to the condensation passage ( 50 ) of the heat exchange section ( 42 ) from the evaporation passage ( 52 ) via a gas piping ( 46 ),
 wherein:   the natural circulation circuit ( 62 ) includes an evaporator (EP) comprising a set of a plurality of evaporation pipes ( 56 ) and condensation passages ( 50 ) equal in number to the plurality of evaporation pipes ( 56 ), and carbon dioxide is used as a refrigerant which circulates through the natural circulation circuit ( 62 ),   a liquid piping ( 44 ) connecting to an outflow end ( 50   b ) of the condensation passage ( 50 ) is connected to one of the plurality of evaporation pipes ( 56 ) that is different from the evaporation pipe ( 56 ) to which a gas piping ( 46 ) coupled to an inflow end ( 50   a ) of the condensation passage ( 50 ) is connected, and a gas piping ( 46 ) which connects to an outflow end ( 52   b ) of the evaporation pipe ( 56 ) is connected to one of the plurality of condensation passages ( 50 ) that is different from the condensation passage ( 50 ) to which a liquid piping ( 44 ) coupled to an inflow end ( 52   a ) of the evaporation pipe ( 56 ) is connected, thereby constructing a single natural circulation circuit ( 62 ) as a whole,   the each evaporation pipe ( 56 ) is formed bent in a meandering manner in such a way that a straight portion ( 56   a ) extends in a transverse direction intersecting a flow direction of air which circulates the evaporation pipes ( 56 ),   the liquid piping ( 44 ) is connected to a part of the evaporation pipe ( 56 ) which is downstream of the flow direction of air, and the gas piping ( 46 ) is connected to a part of the evaporation pipe ( 56 ) which is upstream of the flow direction of air, and   the plurality of evaporation pipes ( 56 ) are disposed in layers apart from one another in an up and down relation.   
     
     
         3 . The cooling device according to  claim 1 , wherein:
 an inflow end ( 52   a ) to which the liquid piping ( 44 ) of the evaporation passage ( 52 ) connects is located at a position lower than an outflow end ( 52   b ) to which the gas piping ( 46 ) connects.   
     
     
         4 . The cooling device according to  claim 1 , wherein:
 the each evaporation pipe ( 56 ) is formed in a steplike manner in the flow direction of air circulating the evaporation pipes ( 56 ) by a stepped portion ( 56 C) at which the straight portions ( 56   a ) are arranged so as to at least partially overlap each other vertically, and the plurality of evaporation pipes ( 56 ) formed in the steplike manner are disposed in layers in such a way that individual steps have an up and down relation.   
     
     
         5 . The cooling device according to  claim 1 , wherein:
 heat transfer promotion members ( 58 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 ) are disposed at a periphery of the evaporation pipe ( 56 ), and the heat transfer promotion members ( 58 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 ) at adjacent straight portions ( 56   a ) of the evaporation pipe ( 56 ) bent in the meandering manner are formed so as to be apart from one another, and   the plurality of evaporation pipes ( 56 ) are disposed in layers in an up and down relation with the heat transfer promotion members ( 58 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 ) apart from one another.   
     
     
         6 . The cooling device according to  claim 1 , wherein:
 the natural circulation circuit ( 48 ,  62 ) is thermally connected via the heat exchange section ( 42 ) to a circuit ( 34 ) on a primary side of a machine compression type which forcibly circulates a refrigerant.   
     
     
         7 . The cooling device according to  claim 2 , wherein:
 an inflow end ( 52   a ) to which the liquid piping ( 44 ) of the evaporation passage ( 52 ) connects is located at a position lower than an outflow end ( 52   b ) to which the gas piping ( 46 ) connects.