Heat exchanger for air and freezer device

Abstract

Surface portions A with a low heat capacity and surface portions B to which frost or ice is poorly bound or attached are discretely distributed on the heat exchange surface. The surface portions A and the surface portions B have features by which, when heating the heat exchanger to which frost or ice is attached, frost or ice in contact with the surface portions A melts earlier than frost or ice in contact with the surface portions B, and at least a part of frost or ice attached to the surface portions B is made partially continuous with at least a part of frost or ice attached to the surface portions A and is thereby released from the surface portions B by its own weight. The heat exchanger having such a heat exchange surface is used as an evaporator of a refrigeration apparatus.

1 . An air heat exchanger characterized in that the air heat exchanger comprises fins that form a surface for heat exchange with air, and heat exchange pipes that are disposed in thermally conductive connection with the fins and circulate a heating medium therein, 
 wherein the fins have a surface for heat exchange with air comprising a surface structure in which surface portions A with a low heat capacity and surface portions B to which frost or ice is poorly bound and attached are discretely distributed, and    wherein the surface portions A and the surface portions B satisfy the following feature 1 and feature 2:    feature 1 is a feature by which interfacial frost or ice in contact with the surface portions A melts earlier than interfacial frost or ice in contact with the surface portions B when heating the surface of a member to which frost or ice is attached; and    feature 2 is a feature by which frost or ice attached to the surface portions B and at least a part of frost or ice attached to the surface portions A are released in a combined manner by their own weight from the surface of a member to which frost or ice is attached when heating the surface of the member.    
     
     
         2 . An air heat exchanger characterized in that the air heat exchanger comprises fins that form a surface for heat exchange with air, and heat exchange pipes that are disposed in thermally conductive connection with the fins and circulate a heating medium therein, and 
 wherein the fins have a surface for heat exchange with air coated with a film formed from a surface treatment composition composed of:    (A) a water-repellent binder resin,    (B-1) a simple carbon substance with DBP absorbed in an amount of 45 to 450 cm 3 /100 g, and    (C) a dispersing agent.    
     
     
         3 . An air heat exchanger characterized in that the air heat exchanger comprises fins that form a surface for heat exchange with air, and heat exchange pipes that are disposed in thermally conductive connection with the fins and circulate a heating medium therein, and 
 wherein the fins have a surface for heat exchange with air coated with a film formed from a surface treatment composition composed of:    (A) a water-repellent binder resin,    (B-2) a simple carbon substance with a specific surface area by nitrogen adsorption of 30 to 400 m 2 /g, and    (C) a dispersing agent.    
     
     
         4 . An air heat exchanger characterized in that the air heat exchanger comprises fins that form a surface for heat exchange with air, and heat exchange pipes that are disposed in thermally conductive connection with the fins and circulate a heating medium therein, and 
 wherein the fins have a surface for heat exchange with air coated with a film formed from a surface treatment composition composed of:    (A) a water-repellent binder resin,    (B-3) a simple carbon substance with DBP absorbed in an amount of 45 to 450 cm 3 /100 g and a specific surface area by nitrogen adsorption of 30 to 400 m 2 /g, and    (C) a dispersing agent.    
     
     
         5 . The air heat exchanger according to  claim 2 , wherein the surface composition is a surface treatment composition that provides a film with an initial sliding angle of 15° or less, the sliding angle defined as an angle of a sample plate at which water droplets begin to roll down when 4 μL of distilled water is added dropwise onto the sample plate horizontally placed under environmental conditions of a temperature of 17±1° C. and a relative humidity of 60±2% to form the water droplets, and then the sample plate is inclined at increasing angles with an increment of 0.1°.  
     
     
         6 . The air heat exchanger according to  claim 2 , wherein the surface treatment composition comprises simple carbon substance (B-1) in an amount of 25 to 400 parts by weight and the dispersing agent (C) in an amount of 5 to 100 parts by weight based on 100 parts by weight of the water-repellent binder resin (A).  
     
     
         7 . The air heat exchanger according to  claim 2 , wherein the water-repellent binder resin (A) is a fluororesin.  
     
     
         8 . The air heat exchanger according to  claim 7 , wherein the fluororesin is a fluorine-containing copolymer with a number average molecular weight of 1,000 to 500,000 composed of 
 (1) a fluoroolefin structural unit (1) represented by the formula (I):      —CF 2 —CFX—  (I)    wherein X is a fluorine atom, a chlorine atom, a hydrogen atom, or a trifluoromethyl group, (2) a β-methyl substituted α-olefin structural unit (2) represented by the formula (II):      —CH 2 —CR(CH 3 )—  (II)    wherein R is a C 1  to C 8  alkyl group,    (3) a structural unit (3) based on a monomer having a chemically curable group,    (4) a structural unit (4) based on a monomer having an ester group on the side chain, and    (5) a structural unit (5) based on a different copolymerizable monomer, 
 the copolymer comprising the structural unit (1) in an amount of 20 to 60 mol %, the structural unit (2) in an amount of 5 to 25 mol %, the structural unit (3) in an amount of 1 to 45 mol %, the structural unit (4) in an amount of 1 to 45 mol %, and the structural unit (5) in an amount of 0 to 45 mol %, provided that the structural units (1) and (2) are 40 to 90 mol % in total.  
   
     
     
         9 . The air heat exchanger according to  claim 2 , wherein the simple carbon substance (B-1) is a simple carbon substance pretreated with the dispersing agent (C).  
     
     
         10 . The air heat exchanger according to  claim 2 , wherein the simple carbon substance (B-1) is carbon black or carbon nanotube.  
     
     
         11 . The air heat exchanger according to  claim 3 , wherein the simple carbon substance (B-2) is a simple carbon substance pretreated with the dispersing agent (C).  
     
     
         12 . The air heat exchanger according to  claim 3 , wherein the simple carbon substance (B-2) is carbon black or carbon nanotube.  
     
     
         13 . The air heat exchanger according to  claim 4 , wherein the simple carbon substance (B-3) is a simple carbon substance pretreated with the dispersing agent (C).  
     
     
         14 . The air heat exchanger according to  claim 4 , wherein the simple carbon substance (B-3) is carbon black or carbon nanotube.  
     
     
         15 . The air heat exchanger according to  claim 2 , wherein the dispersing agent (C) is a polymer comprising a recurring unit derived from a vinyl monomer having a fluoroalkyl group.  
     
     
         16 . The air heat exchanger according to  claim 15 , wherein the polymer is a copolymer with a non-fluorine vinyl monomer.  
     
     
         17 . The air heat exchanger according to  claim 2 , wherein the surface treatment composition further comprises a crosslinking agent (E), and the water-repellent binder resin (A) is a resin having a chemically curable group.  
     
     
         18 . The air heat exchanger according to  claim 17 , wherein the surface treatment composition comprises the crosslinking agent (E) in an amount of 0.1 to 5 equivalents based on one equivalent of the chemically curable group in the water-repellent binder resin having the chemically curable group.  
     
     
         19 . The air heat exchanger according to  claim 2 , wherein the surface treatment composition provides a film with an initial water microdroplet sliding angle of 15° or less, the angle at which ultrafine water droplets slide defined as an angle of a sample plate at which the water droplets begin to roll down when 1 μL of distilled water is added dropwise onto the sample plate horizontally placed under environmental conditions of a temperature of 17±1° C. and a relative humidity of 60±2% to form the water droplets, and then the sample plate is inclined at increasing angles with an increment of 0.1°.  
     
     
         20 . An air heat exchanger characterized in that the air heat exchanger comprises fins that form a surface for heat exchange with air, and heat exchange pipes that are disposed in thermally conductive connection with the fins and circulate a heating medium therein, and 
 wherein the fins have a surface for heat exchange with air coated with a film formed of a surface treatment composition composed of a water-repellent binder resin, polytetrafluoroethylene particles, a dispersing agent, inorganic particles with a low heat capacity, and a solvent.    
     
     
         21 . The air heat exchanger according to  claim 20 , 
 wherein the water-repellent binder resin is a fluororesin,    wherein the polytetrafluoroethylene particles have a weight average molecular weight of 500 to 200,000 and a mean particle diameter of 0.1 μm or more,    wherein the dispersing agent is a polymer comprising a recurring unit derived from a vinyl monomer having a fluoroalkyl group,    wherein the inorganic particles with a low heat capacity have a molar heat capacity of 6 Ca/JK −1 mol −1  to 7 Ca/JK −1 mol −1  and are electrically conductive,    wherein the solvent is an organic solvent system, and    wherein the composition comprises the polytetrafluoroethylene particles in an amount of 100 to 200 parts by weight, the dispersing agent in an amount of 5 to 30 parts by weight, the inorganic particles with a low heat capacity in an amount of 25 to 200 parts by weight, and the solvent in an amount of 400 to 2,000 parts by weight, based on 100 parts by weight of the water-repellent binder resin.    
     
     
         22 . The air heat exchanger according to  claim 2 , wherein the fins are multiple sheets of plate fins located at predetermined intervals, the heat exchange pipes are disposed so that the pipes penetrate through the multiple plate fins, and the spaces between the fins are formed as air passages.  
     
     
         23 . The air heat exchanger according to  claim 22 , wherein the plate fins are formed as slit fins.  
     
     
         24 . The air heat exchanger according to  claim 22 , wherein the plate fins are formed as louver fins.  
     
     
         25 . The air heat exchanger according to  claim 22 , wherein the plate fins are formed as flat fins and provided with notches at the rear of the heat exchange pipes in the direction along which air passes.  
     
     
         26 . The air heat exchanger according to  claim 22 , wherein the plate fins are provided with dimples on the surface.  
     
     
         27 . The air heat exchanger according to  claim 22 , wherein the plate fins have a large fin pitch formed at the ends from which air flows out.  
     
     
         28 . The air heat exchanger according to  claim 22 , wherein the plate fins have a large fin pitch formed at the lower ends.  
     
     
         29 . The air heat exchanger according to  claim 22 , wherein the plate fins are arranged so that the edges are oblique in the air passages.  
     
     
         30 . The air heat exchanger according to  claim 22 , wherein the heat exchange pipes are arranged in grids.  
     
     
         31 . The air heat exchanger according to  claim 2 , wherein the heat exchange pipes are flat tubes located in multiple rows, the fins are corrugate fins formed so that the waveform parts are perpendicular to the heat exchange pipes, and the spaces formed in parallel with the waveform parts of the fins form air passages.  
     
     
         32 . The air heat exchanger according to  claim 2 , wherein the heat exchange pipes are disposed on the surface perpendicular to the direction along which air flows, and the fins are mesh fins disposed so that the surface of the fins is a surface perpendicular to the direction along which air flows.  
     
     
         33 . A refrigeration apparatus characterized in that the air heat exchanger according to  claim 2  is used as an evaporator.  
     
     
         34 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 2  is used as an outdoor heat exchanger.  
     
     
         35 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 2  is used as an indoor heat exchanger and an outdoor heat exchanger, respectively.  
     
     
         36 . A refrigeration apparatus comprising an evaporator including the air heat exchanger according to  claim 2;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle and operate the blower during defrost operation.  
     
     
         37 . A refrigeration apparatus comprising an evaporator including the air heat exchanger according to  claim 1;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit that, during defrost operation, stops the blower and activates the defrost cycle until interfacial frost or ice in contact with the surface portions A melts, and operates the blower and inactivates the defrost cycle after the interfacial frost or ice in contact with the surface portions A has melted.  
     
     
         38 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 2;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at the highest of speeds that can be selected during heating operation.  
     
     
         39 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 2;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at a higher speed than the highest of speeds that can be selected during heating operation.  
     
     
         40 . The refrigeration apparatus according to  claim 36 , wherein the refrigerant circuit comprises a defrost cycle of a normal cycle hot gas bypass system.  
     
     
         41 . The refrigeration apparatus according to  claim 36 , wherein the refrigerant circuit comprises a defrost cycle of a reverse cycle system.  
     
     
         42 . The refrigeration apparatus according to  claim 36 , wherein the refrigerant circuit comprises a defrost cycle of a simple hot gas bypass system.  
     
     
         43 . The air heat exchanger according to  claim 3 , wherein the surface composition is a surface treatment composition that provides a film with an initial sliding angle of 15° or less, the sliding angle defined as an angle of a sample plate at which water droplets begin to roll down when 4 μL of distilled water is added dropwise onto the sample plate horizontally placed under environmental conditions of a temperature of 17±1° C. and a relative humidity of 60±2% to form the water droplets, and then the sample plate is inclined at increasing angles with an increment of 0.1°.  
     
     
         44 . The air heat exchanger according to  claim 4 , wherein the surface composition is a surface treatment composition that provides a film with an initial sliding angle of 15° or less, the sliding angle defined as an angle of a sample plate at which water droplets begin to roll down when 4 μL of distilled water is added dropwise onto the sample plate horizontally placed under environmental conditions of a temperature of 17±1° C. and a relative humidity of 60±2% to form the water droplets, and then the sample plate is inclined at increasing angles with an increment of 0.1°.  
     
     
         45 . The air heat exchanger according to  claim 3 , wherein the surface treatment composition comprises the simple carbon substance (B-2) in an amount of 25 to 400 parts by weight and the dispersing agent (C) in an amount of 5 to 100 parts by weight based on 100 parts by weight of the water-repellent binder resin (A).  
     
     
         46 . The air heat exchanger according to  claim 4 , wherein the surface treatment composition comprises the simple carbon substance (B-3) in an amount of 25 to 400 parts by weight and the dispersing agent (C) in an amount of 5 to 100 parts by weight based on 100 parts by weight of the water-repellent binder resin (A).  
     
     
         47 . The air heat exchanger according to  claim 3 , wherein the water-repellent binder resin (A) is a fluororesin.  
     
     
         48 . The air heat exchanger according to  claim 4 , wherein the water-repellent binder resin (A) is a fluororesin.  
     
     
         49 . The air heat exchanger according to  claim 3 , wherein the dispersing agent (C) is a polymer comprising a recurring unit derived from a vinyl monomer having a fluoroalkyl group.  
     
     
         50 . The air heat exchanger according to  claim 4 , wherein the dispersing agent (C) is a polymer comprising a recurring unit derived from a vinyl monomer having a fluoroalkyl group.  
     
     
         51 . The air heat exchanger according to  claim 3 , wherein the surface treatment composition further comprises a crosslinking agent (E), and the water-repellent binder resin (A) is a resin having a chemically curable group.  
     
     
         52 . The air heat exchanger according to  claim 4 , wherein the surface treatment composition further comprises a crosslinking agent (E), and the water-repellent binder resin (A) is a resin having a chemically curable group.  
     
     
         53 . The air heat exchanger according to  claim 3 , wherein the surface treatment composition provides a film with an initial water microdroplet sliding angle of 15° or less, the angle at which ultrafine water droplets slide defined as an angle of a sample plate at which the water droplets begin to roll down when 1 μL of distilled water is added dropwise onto the sample plate horizontally placed under environmental conditions of a temperature of 17±1° C. and a relative humidity of 60±2% to form the water droplets, and then the sample plate is inclined at increasing angles with an increment of 0.1°.  
     
     
         54 . The air heat exchanger according to  claim 4 , wherein the surface treatment composition provides a film with an initial water microdroplet sliding angle of 15° or less, the angle at which ultrafine water droplets slide defined as an angle of a sample plate at which the water droplets begin to roll down when 1 μL of distilled water is added dropwise onto the sample plate horizontally placed under environmental conditions of a temperature of 17±1° C. and a relative humidity of 60±2% to form the water droplets, and then the sample plate is inclined at increasing angles with an increment of 0.1°.  
     
     
         55 . The air heat exchanger according to  claim 3 , wherein the fins are multiple sheets of plate fins located at predetermined intervals, the heat exchange pipes are disposed so that the pipes penetrate through the multiple plate fins, and the spaces between the fins are formed as air passages.  
     
     
         56 . The air heat exchanger according to  claim 4 , wherein the fins are multiple sheets of plate fins located at predetermined intervals, the heat exchange pipes are disposed so that the pipes penetrate through the multiple plate fins, and the spaces between the fins are formed as air passages.  
     
     
         57 . The air heat exchanger according to  claim 20 , wherein the fins are multiple sheets of plate fins located at predetermined intervals, the heat exchange pipes are disposed so that the pipes penetrate through the multiple plate fins, and the spaces between the fins are formed as air passages.  
     
     
         58 . The air heat exchanger according to  claim 3 , wherein the heat exchange pipes are flat tubes located in multiple rows, the fins are corrugate fins formed so that the waveform parts are perpendicular to the heat exchange pipes, and the spaces formed in parallel with the waveform parts of the fins form air passages.  
     
     
         59 . The air heat exchanger according to  claim 4 , wherein the heat exchange pipes are flat tubes located in multiple rows, the fins are corrugate fins formed so that the waveform parts are perpendicular to the heat exchange pipes, and the spaces formed in parallel with the waveform parts of the fins form air passages.  
     
     
         60 . The air heat exchanger according to  claim 20 , wherein the heat exchange pipes are flat tubes located in multiple rows, the fins are corrugate fins formed so that the waveform parts are perpendicular to the heat exchange pipes, and the spaces formed in parallel with the waveform parts of the fins form air passages.  
     
     
         61 . The air heat exchanger according to  claim 3 , wherein the heat exchange pipes are disposed on the surface perpendicular to the direction along which air flows, and the fins are mesh fins disposed so that the surface of the fins is a surface perpendicular to the direction along which air flows.  
     
     
         62 . The air heat exchanger according to  claim 4 , wherein the heat exchange pipes are disposed on the surface perpendicular to the direction along which air flows, and the fins are mesh fins disposed so that the surface of the fins is a surface perpendicular to the direction along which air flows.  
     
     
         63 . The air heat exchanger according to  claim 20 , wherein the heat exchange pipes are disposed on the surface perpendicular to the direction along which air flows, and the fins are mesh fins disposed so that the surface of the fins is a surface perpendicular to the direction along which air flows.  
     
     
         64 . A refrigeration apparatus characterized in that the air heat exchanger according to  claim 3  is used as an evaporator.  
     
     
         65 . A refrigeration apparatus characterized in that the air heat exchanger according to  claim 4  is used as an evaporator.  
     
     
         66 . A refrigeration apparatus characterized in that the air heat exchanger according to  claim 20  is used as an evaporator.  
     
     
         67 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 3  is used as an outdoor heat exchanger.  
     
     
         68 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 4  is used as an outdoor heat exchanger.  
     
     
         69 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 20  is used as an outdoor heat exchanger.  
     
     
         70 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 3  is used as an indoor heat exchanger and an outdoor heat exchanger, respectively.  
     
     
         71 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 4  is used as an indoor heat exchanger and an outdoor heat exchanger, respectively.  
     
     
         72 . A refrigeration apparatus configured as a heat pump air conditioner, characterized in that the air heat exchanger according to  claim 20  is used as an indoor heat exchanger and an outdoor heat exchanger, respectively.  
     
     
         73 . A refrigeration apparatus comprising an evaporator including the air heat exchanger according to  claim 3;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle and operate the blower during defrost operation.  
     
     
         74 . A refrigeration apparatus comprising an evaporator including the air heat exchanger according to  claim 4;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle and operate the blower during defrost operation.  
     
     
         75 . A refrigeration apparatus comprising an evaporator including the air heat exchanger according to  claim 20;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle and operate the blower during defrost operation.  
     
     
         76 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 3;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at the highest of speeds that can be selected during heating operation.  
     
     
         77 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 4;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at the highest of speeds that can be selected during heating operation.  
     
     
         78 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 20;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at the highest of speeds that can be selected during heating operation.  
     
     
         79 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 3;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at a higher speed than the highest of speeds that can be selected during heating operation.  
     
     
         80 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 4;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at a higher speed than the highest of speeds that can be selected during heating operation.  
     
     
         81 . A refrigeration apparatus configured as a heat pump refrigeration apparatus which can be operated for heating and cooling, comprising an evaporator including the air heat exchanger according to  claim 20;  a blower for blowing air to be heat-exchanged with the evaporator across the evaporator; a refrigerant circuit that can be operated in a defrost cycle in which a gas discharged from a compressor is supplied to the evaporator during defrost operation; and a control unit for controlling the apparatus to activate the defrost cycle during defrost operation and set the operation speed of the blower during the defrost operation at a higher speed than the highest of speeds that can be selected during heating operation.