WO2020100766A1 - Heat exchanger and heat exchanger defrosting method - Google Patents

Heat exchanger and heat exchanger defrosting method Download PDF

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Publication number
WO2020100766A1
WO2020100766A1 PCT/JP2019/043982 JP2019043982W WO2020100766A1 WO 2020100766 A1 WO2020100766 A1 WO 2020100766A1 JP 2019043982 W JP2019043982 W JP 2019043982W WO 2020100766 A1 WO2020100766 A1 WO 2020100766A1
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WO
WIPO (PCT)
Prior art keywords
heat transfer
transfer tube
defrosting
defrost
heat
Prior art date
Application number
PCT/JP2019/043982
Other languages
French (fr)
Japanese (ja)
Inventor
雅士 加藤
耕作 西田
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株式会社前川製作所
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Publication of WO2020100766A1 publication Critical patent/WO2020100766A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/06—Removing frost
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/04—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by preventing the formation of continuous films of condensate on heat-exchange surfaces, e.g. by promoting droplet formation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F17/00—Removing ice or water from heat-exchange apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/26—Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators

Definitions

  • the present disclosure relates to a heat exchanger and a defrosting method for the heat exchanger.
  • Fin-tube heat exchangers are used as heat exchangers such as air coolers installed in freezers and freezers.
  • the fin tube type heat exchanger radiating fins are likely to be covered with frost, and the frost layer formed between the fins blocks the air flow, so that frequent defrost operation is required. Therefore, the present inventors have proposed a defrosting method of sublimating and removing frost attached to the fins and the heat transfer tubes (Patent Document 1).
  • frost is sublimated and scattered on the air flow, so that no molten water is generated. Therefore, there is an advantage that the work of removing the melted water from the heat exchanger becomes unnecessary and defrosting can be performed while the operation of the air cooler is continued.
  • One embodiment it is possible to suppress the decrease in thermal efficiency of the heat exchanger due to the defrost operation, and to prevent the frost separated from the adhesion surface during defrosting from re-adhering to the heat transfer surface on the downstream side, and further, It is an object of the present invention to propose a defrosting device capable of efficiently operating a cooling device while suppressing wasteful defrosting heating of a heat exchanger.
  • the heat exchanger is A gas flow path through which the cooled gas flows, In the gas flow path, a plurality of heat transfer tubes extending along a first direction orthogonal to the flow direction of the gas to be cooled in the gas flow path, A defrost unit for defrosting the defrost target pipe among the plurality of heat transfer tubes, Equipped with The plurality of heat transfer tubes are arranged such that a plurality of heat transfer tube rows formed by the plurality of heat transfer tubes arranged along a second direction orthogonal to the flow direction and the first direction are arranged in the flow direction.
  • the gas flow path includes a plurality of flow path regions arranged in the second direction,
  • the plurality of heat transfer tubes respectively correspond to the plurality of flow path areas and belong to two or more heat transfer tube rows adjacent to each other in the same flow path area in the flow direction.
  • Including a plurality of heat transfer tube groups formed by The defrost unit is configured to selectively defrost the heat transfer tubes of one or more heat transfer tube groups of the plurality of heat transfer tube groups as the defrosting target tubes.
  • the plurality of heat transfer tubes provided in the gas flow path are configured of a plurality of heat transfer tube groups, and the heat transfer tubes that form one or more heat transfer tube groups by the defrost unit serve as defrost target tubes. Defrosted selectively. Since the degree of adhesion and growth of frost is different for each heat transfer tube group, the time when the gas flow path is blocked by the grown frost layer is different for each heat transfer tube group.
  • the defrost unit is configured to selectively defrost only the heat transfer tube row on the most upstream side in the flow direction of the plurality of heat transfer tube rows as the defrosting target tube.
  • the heat transfer surface of the most upstream heat transfer tube in the flow direction has a high heat transfer coefficient, and the mist (liquid and solid) contained in the gas to be cooled collides with the most upstream heat transfer tube and the tip of the fin due to inertial force. In addition, a phenomenon occurs in which frost is concentrated on these parts and the growth of frost is accelerated.
  • the most upstream heat transfer tube row can be preferentially defrosted, As a result, it is possible to suppress the growth of frost on the heat transfer tube row on the most upstream side.
  • a plate-shaped heat radiating member is provided in the gas flow path along the flow direction so that the plurality of heat transfer tubes penetrate or contact each other. According to the configuration of (3), since the heat transfer area is increased by including the plate-shaped heat dissipation member, the heat transfer performance of the heat exchanger can be improved. Moreover, since the plate-shaped heat dissipation member is provided along the flow direction of the gas to be cooled, it is possible to suppress the turbulence of the gas to be cooled.
  • a temperature boundary layer is formed on the surface of the plate-shaped heat dissipation member in which the turbulence of the gas to be cooled is suppressed, and the temperature gradually decreases toward the surface of the plate-shaped heat dissipation member. Since the formation of the temperature boundary layer suppresses the heat transfer coefficient between the gas to be cooled and the plate-shaped heat dissipation member, it is possible to suppress the growth of the frost layer formed on the surface of the plate-shaped heat dissipation member. On the contrary, if the temperature boundary layer is disturbed (for example, a louver fin or the like), the heat transfer coefficient is increased and the growth of frost is promoted. By utilizing this, it is possible to optimally design a place where frost is to be grown or a place where frost is not desired, that is, a growth amount of frost in each place in association with a heat exchange amount and a defrosting interval.
  • a plurality of the plate-shaped heat dissipation members are arranged in parallel along the flow direction at intervals that do not disturb the temperature boundary layer for each heat transfer tube group. According to the configuration of (4), since the plurality of plate-shaped heat dissipation members are arranged, the heat transfer area can be increased and the heat transfer performance can be improved. Further, since the plate-shaped heat radiating members are arranged in parallel along the flow direction of the gas to be cooled, the turbulence of the gas to be cooled can be suppressed, whereby the temperature of the gap between the plate-shaped heat radiating members of the adjacent heat transfer tube groups can be suppressed.
  • the boundary layer is maintained, and the growth of the frost layer at the upstream end in the flow direction of the plate-shaped heat dissipation member facing the gap is suppressed, whereby the concentration of frost formation can be suppressed and partial blockage can be suppressed. Further, according to this configuration, even if there is a temperature difference between the adjacent heat transfer tube groups at the time of defrosting, since this void serves as a heat insulating material, the influence on the adjacent heat transfer tube groups is suppressed, and the heat exchange efficiency is improved. The decrease can be suppressed.
  • the plate-shaped heat dissipation member extends from the heat transfer tube provided on the most upstream side in the flow direction to one or more heat transfer tubes adjacent to the heat transfer tube in the flow direction. Since the temperature boundary layer is thin at the tip end portion of the plate-shaped heat dissipation member, the heat transfer coefficient between the gas to be cooled and the plate-shaped heat dissipation member is promoted, and the growth of frost is accelerated. Therefore, by extending the plate-shaped heat dissipation member to the heat transfer tube on the downstream side, the formation of a new tip portion is eliminated, and the temperature boundary layer is present in the area other than the tip portion. Thereby, the growth of frost can be suppressed in the area other than the tip portion.
  • the plate-shaped heat dissipating member is disposed so as to straddle two or more heat transfer tube groups in the flow direction, and has a heat insulating region in a region between the heat transfer tube groups that suppresses heat transfer between the heat transfer tube groups.
  • the plate-shaped heat dissipation member has the heat insulating region for suppressing heat transfer between the heat transfer pipe groups in the region between the heat transfer pipe groups.
  • the heat added in the defrost operation is prevented from being transferred to the heat transfer tube group during the cooling operation and lowering the cooling efficiency of the heat exchanger. it can.
  • the defrost unit may supply, for each heat transfer tube group, one or more defrost fluids capable of maintaining the frost adhesion surface temperature of the heat transfer tubes below 0 ° C. and higher than the temperature of the gas to be cooled. Includes a defrost fluid supply.
  • the defrost fluid supply unit can maintain the frost adhesion surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled for the heat transfer tube group performing the defrost operation. By supplying such a defrosting fluid, sublimation defrosting that sublimates and removes the frost adhering to the adhering surface becomes possible. Note that a plurality of defrost fluid supply units may be provided as needed.
  • the defrosting method for the heat exchanger is A gas flow path through which the gas to be cooled flows, a plurality of heat transfer tubes extending in the gas flow path along a first direction orthogonal to the flow direction of the gas to be cooled in the gas flow path, and the plurality of heat transfer tubes
  • a row of heat transfer tubes formed by heat tubes is arranged so as to be lined up in the flow direction of the cooled gas, and the gas flow path includes a plurality of flow path areas lined up in the second direction.
  • the heat pipes are formed by the plurality of heat transfer tubes that respectively correspond to the plurality of flow path regions and that belong to two or more heat transfer tube rows that are adjacent to each other in the flow direction in the same flow path region.
  • a defrosting method for a heat exchanger including a plurality of heat transfer tube groups comprising: A defrosting step of selecting one or more heat transfer tube groups from the plurality of heat transfer tube groups as a defrosting target tube and sequentially defrosting each of the one or more heat transfer tube groups in sequence is provided.
  • one or more heat transfer tube groups are selected from the plurality of heat transfer tube groups as defrosting target tubes, and defrosting is sequentially repeated for each of the one or more heat transfer tube groups. Therefore, by appropriately selecting the order of defrosting each heat transfer tube group, it is possible to prevent the cooling gas around the heat transfer surface from being blocked by the frost layer while suppressing the decrease in the heat efficiency of the heat exchanger due to the heat added during defrosting. In addition, it is possible to prevent the frost separated from the adhering surface during defrosting from adhering again to the heat transfer surface on the downstream side. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger.
  • the defrost unit is configured to selectively defrost only the heat transfer tube row on the most upstream side in the flow direction among the plurality of heat transfer tube rows as the defrosting target tube
  • the defrosting step includes a step of selectively defrosting only the heat transfer tube row on the most upstream side in the flow direction as the defrosting target tube.
  • the 1 defrost time required to defrost all the heat transfer tube groups once is set in accordance with the limit time when the amount of frost adhering to at least a part of the heat transfer tubes reaches the upper limit of the allowable value, and the 1 defrost time is set.
  • the defrost execution time interval for each of the heat transfer tube groups According to the above method (10), by setting the limit time to the upper limit value at which the flow of the gas to be cooled is not blocked, the defrost operation can be performed so that the gas to be cooled is not blocked in each heat transfer tube group. ..
  • the defrost execution time interval of each of the plurality of heat transfer tube groups is set to be longer for the heat transfer tube group arranged on the downstream side in the flow direction.
  • the growth of frost tends to be slower on the downstream side in the flow direction of the cooled gas. Therefore, by setting the defrosting time interval to be longer for the heat transfer tube group on the downstream side in the flow direction in which frost growth is slower, the frequency of defrosting operation can be reduced, and thereby the reduction in cooling efficiency due to defrosting operation can be suppressed.
  • a defrost fluid capable of maintaining the surface temperature of the frost below 0 ° C. and higher than the temperature of the gas to be cooled is supplied to the heat transfer tube, and the frost attached to the heat transfer tube is sublimated by the heat of the defrost fluid.
  • the defrost fluid capable of maintaining the frost adhesion surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled is supplied to the heat transfer tube performing the defrost operation. , Sublimation defrost that sublimes and removes the frost adhering to the adhering surface becomes possible.
  • the temperature difference between the gas to be cooled and the defrost fluid is set to be smaller as the heat transfer tube group is arranged on the downstream side in the flow direction.
  • the smaller the temperature difference between the gas to be cooled and the defrost fluid the smaller the effect of removing frost, but the lowering of the thermal efficiency of the heat exchanger during the cooling operation can be suppressed. Therefore, by making the temperature difference smaller toward the downstream side in the flow direction where frost formation is slower, it is possible to prevent the gas flow passage from being blocked due to frost formation, while suppressing a decrease in cooling efficiency of the heat exchanger.
  • the defrosting step When the heat transfer tube group arranged on the upstream side in the flow direction is subjected to defrosting, the flow direction is reversed.
  • the flow direction of the gas to be cooled is reversed so that the frost separated from the adhering surface is on the downstream side. It is possible to suppress re-adhesion to the heat transfer tube, and it is possible to perform processing on the upstream side. Moreover, the frost adhering to the tip portion can be efficiently removed. Further, the cooled gas whose temperature has been raised by the defrost heat source once returns to the upstream side, is mixed, and flows into another heat transfer tube group, so that the temperature unevenness in the downstream of the heat exchanger can be suppressed.
  • the reduction of the thermal efficiency of the heat exchanger due to the defrost operation is suppressed, and the frost separated from the adhering surface during the defrost operation causes the heat transfer surface to be defrosted. It is possible to suppress reattachment to the. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger.
  • expressions such as “identical”, “equal”, and “homogeneous” that indicate that they are in the same state are not limited to a state in which they are exactly equal to each other. It also represents the existing state.
  • the representation of a shape such as a quadrangle or a cylinder does not only represent a shape such as a quadrangle or a cylinder in a geometrically strict sense, but also an uneven portion or a chamfer within a range in which the same effect can be obtained.
  • the shape including parts and the like is also shown.
  • the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.
  • FIG. 1 is a perspective view schematically showing a heat exchanger according to one embodiment.
  • the heat exchanger 10 shown in FIG. 1 is an air cooler provided in, for example, a freezer or a freezer.
  • the casing 12 of the heat exchanger 10 has an open front surface that flows in from the cooled air a and a rear surface that flows out.
  • the casing 12 of the heat exchanger 10 flows in from the front surface of the casing 12 by the operation of the fan 14 (14a, 14b, 14c) and the like.
  • a flow path for the air to be cooled a flowing out from is formed.
  • a plurality of heat transfer tubes 16 are provided in this cooling air flow path.
  • the heat transfer tube 16 extends along the width direction (arrow b direction) (first direction) orthogonal to the flow direction (arrow a direction) of the cooled air a in the cooling air flow path.
  • a defrost unit 18 for defrosting the heat transfer tube 16 selected as the defrosting target tube among the plurality of heat transfer tubes 16 is provided.
  • the plurality of heat transfer tubes 16 are formed by a plurality of heat transfer tubes 16 arranged in a vertical direction (arrow c direction) (second direction) orthogonal to the flow direction of the cooled air a and the arrow b direction.
  • the rows are arranged so that a plurality of rows are arranged in the flow direction.
  • the heat transfer tube 16 is illustrated only in an upper region in the casing 12, and the heat transfer tube 16 is not illustrated in other areas, but in reality, the heat transfer tube 16 is arranged also in other areas, As with the upper region, there are multiple heat transfer tube groups.
  • the cooling air flow passage includes a plurality of flow passage regions Fa, Fb and Fc arranged in the direction of arrow c.
  • the plurality of heat transfer tubes 16 are formed by the plurality of heat transfer tubes 16 respectively corresponding to the plurality of flow path areas Fa to Fc and belonging to two or more heat transfer tube rows adjacent to each other in the same flow path area in the flow direction.
  • the defrost unit 18 is configured to selectively defrost the heat transfer tubes 16 of one or more heat transfer tube groups among the plurality of heat transfer tube groups as defrosting target tubes.
  • one or more heat transfer tube groups among the heat transfer tube groups Ta, Tb, Tc, ... are selectively defrosted as tubes to be defrosted. Since the degree of adhesion and growth of frost is different for each heat transfer tube group, the time when the gas flow path is blocked by the grown frost layer is different for each heat transfer tube group. Therefore, by appropriately selecting the order of defrosting each heat transfer tube group, the thermal efficiency of the heat exchanger 10 is reduced by the heat applied during defrosting while preventing the air passages from being blocked on the heat transfer surface of each heat transfer tube group. In addition, it is possible to prevent the frost separated from the adhering surface during defrosting from re-adhering to the heat transfer surface. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger (heating added to the heat transfer tubes by the heat of the defrost fluid).
  • each heat transfer tube group For example, for each heat transfer tube group, the blocking time due to frost formation on the air flow path around the heat transfer surface is obtained, and each heat transfer tube group performs defrost operation at least once per blocking time. Thereby, the blockage of the air flow path of each heat transfer tube group can be suppressed.
  • the upstream heat transfer tube group and the downstream heat transfer tube group are simultaneously defrosted. As a result, it is possible to prevent the frost separated in the upstream heat transfer tube from reattaching to the downstream heat transfer tube.
  • the defrost time interval is set longer for the downstream heat transfer tube group in which the growth of frost is slower. As a result, it is possible to suppress a decrease in thermal efficiency of the heat exchanger due to defrost.
  • FIG. 2 is a defrost unit for supplying a refrigerant to the heat transfer tubes 16 to cool the cooled air a during the cooling operation of the heat exchanger 10 and a defrost unit for supplying the defrost fluid to the heat transfer tube group to be defrosted during the defrost operation.
  • 18 shows an embodiment of 18 configurations.
  • the refrigerant circulating in the refrigerant circuit 22 is sucked into the compressor 24 in a gaseous state, pressurized by the compressor 24, cooled by the condenser 26, and liquefied.
  • the refrigerant liquid liquefied by the condenser 26 is once stored in the receiver 28, and then depressurized via the expansion valve 30.
  • the refrigerant decompressed by the expansion valve 30 is supplied to the heat transfer pipe 16 of the heat exchanger 10 through the check valve 32 provided in each heat transfer pipe group Ta, Tb, and Tc of the heat exchanger 10, and the cooled air a Is cooled to a predetermined cooling temperature.
  • the refrigerant that has been used to cool the cooled air a is returned to the refrigerant circuit 22.
  • the high-pressure refrigerant (gas phase portion) in the receiver 28 is stored in the buffer tank 44 in the heat transfer tube group that has become the defrost target tube, and is supplied through the defrost flow path 34.
  • the refrigerant under high pressure is stored in the buffer tank 44 after adjusting the temperature, pressure, and other conditions. That is, the pressure is adjusted through the pressure adjusting valve 36, and the temperature is reduced by the heating unit 46 so that the temperature, pressure, and other conditions are adjusted.
  • This defrosting refrigerant gas is sent to the heat transfer tube group that is the defrosting target tube, and is provided for defrosting in this heat transfer tube group.
  • the refrigerant gas After the refrigerant gas is condensed and liquefied inside the heat transfer tube, it is expanded and decompressed through the capillary tube 38 and joins the low pressure refrigerant line. After that, it is vaporized and gasified through another heat transfer tube group and is returned to the refrigerant circuit 22.
  • the capillary tube 38 may be a solenoid valve or an expansion valve.
  • the refrigerant circuit 22 and the defrost passage 34 are provided with solenoid valves 47 and 49 for opening and closing.
  • the defrost unit 18 selectively selects, as a defrost target tube, only the heat transfer tube row on the most upstream side in the flow direction (heat transfer tube row belonging to the heat transfer tube group Ta in this embodiment) among the plurality of heat transfer tube rows. Configured to defrost.
  • the most upstream heat transfer tube array has a high heat transfer coefficient, and the mist (liquid and solid) contained in the gas to be cooled collides with the upstream end portion by the inertial force, so that frost accumulation and stacking are promoted. As a result, frost is concentrated on the uppermost stream side heat transfer tube row, and the growth of frost is accelerated. Therefore, it is effective to concentrate the defrosting operation on the most upstream heat transfer tube row.
  • the most upstream heat transfer is performed.
  • the defrost frequency can be increased by giving priority to the row of heat tubes. Therefore, it is possible to suppress the growth of frost on the uppermost stream side heat transfer tube row and conversely save energy by suppressing the defrost frequency of the downstream side heat transfer tube group.
  • a plate-shaped heat dissipation member 40 is provided along the flow direction (direction of arrow a) in the cooling air flow path so that the plurality of heat transfer tubes 16 penetrate or contact each other. Since the heat transfer area is increased by providing the plate-shaped heat dissipation member 40, the heat transfer performance of the heat exchanger 10 can be improved. Further, since the plate-shaped heat dissipation member 40 is provided along the flow direction of the cooled air a, it is possible to suppress the disturbance of the cooled air a. As shown in FIG.
  • a temperature boundary layer Bt is formed in which the temperature gradually decreases toward the surface of the plate-shaped heat dissipation member 40. It The formation of this temperature boundary layer lowers the heat transfer coefficient between the cooled air a and the plate-shaped heat dissipation member 40, so that the growth of the frost layer formed on the surface of the plate-shaped heat dissipation member 40 can be suppressed.
  • FIG. 4A schematically shows the temperature distribution of the temperature boundary layer Bt.
  • the temperature boundary layer Bt becomes thinner toward the upstream side. Therefore, the heat transfer between the air to be cooled a and the cooling medium flowing in the heat transfer tube 16 is promoted toward the upstream side. Therefore, it is assumed that the amount of frost attached to the upstream end portion 40a of the plate-shaped heat dissipation member 40 increases during the normal cooling operation. On the other hand, on the downstream side in the flow direction, the growth of the frost layer formed on the surface of the plate-shaped heat dissipation member 40 can be suppressed by the formation of the temperature boundary layer Bt.
  • the plate-shaped heat dissipation members 40 are arranged in parallel along the flow direction at intervals such that they do not disturb the temperature boundary layer Bt for each heat transfer tube group.
  • the heat transfer area is increased and the heat transfer performance can be improved.
  • the plate-shaped heat dissipation member 40 is arranged along the flow direction of the cooled air a, it is possible to suppress the disturbance of the cooled air a.
  • the plurality of plate-shaped heat dissipation members 40 are arranged at intervals so as not to disturb the temperature boundary layer Bt for each heat transfer tube group, a gap between the plate-shaped heat dissipation members of adjacent heat transfer tube groups is formed.
  • the temperature boundary layer Bt is maintained, and the growth of the frost layer at the end of the plate-shaped heat dissipation member facing the gap on the upstream side in the flow direction is suppressed, whereby the concentration of frost can be suppressed and partial blockage can be suppressed.
  • the plate-shaped heat dissipation member 40 can suppress the turbulence of the air to be cooled a maximum by forming the plate-shaped heat dissipation member 40, but the plate-shaped heat dissipation member 40 is not limited to the plate-shaped heat dissipation member, and may have a corrugated shape, a louver shape, or a wave shape.
  • the arrangement of the plurality of heat transfer tubes 16 suppresses the growth of the frost layer without forming the turbulent flow of the cooled air a, and suppresses the concentration of frost formation due to the attachment of mist due to inertia. From the viewpoint, it is preferable to use the lattice arrangement rather than the staggered arrangement with respect to the flow of the cooled air a. In addition, from the viewpoint of promoting heat transfer, it is desirable to arrange in a staggered manner, and it may be appropriately selected in relation to the conditions such as the heat exchange amount and the defrost cycle time.
  • the plate-shaped heat dissipation member 40 moves from the heat transfer tube 16 (16a) provided on the most upstream side in the flow direction of the cooled air a to the heat transfer tube 16 (16a) in the flow direction. It extends to one or more adjacent heat transfer tubes 16.
  • the plate-shaped heat dissipation member 40 is extended to the heat transfer tube 16 on the downstream side so that the second tip portion is not formed. In this way, the temperature boundary layer Bt can be continuously formed to the downstream side, and the growth of frost can be suppressed by not interrupting the temperature boundary layer Bt to the downstream side.
  • the plate-shaped heat dissipation member 40 is arranged so as to straddle two or more heat transfer tube groups Ta and Tb in the flow direction of the cooled air a, and Insulation regions 42 (42a, 42b) that suppress heat transfer between the heat transfer tube groups are provided in the areas between the heat transfer tube groups.
  • Insulation regions 42 42a, 42b
  • the heat transfer tube group Ta on one side of the heat insulating area 42 performs the cooling operation and the heat transfer tube group on the other side.
  • Tb performs the defrosting operation, it is possible to prevent the heat added during the defrosting from being transferred to the heat transfer tube group during the cooling operation and reducing the cooling efficiency of the heat exchanger 10.
  • the heat insulating region 42 (42a) is composed of a gap formed in a length that allows the temperature boundary layer Bt to be maintained without interruption in the flow direction of the cooled air a. Since the air existing in this gap has a heat insulating property, the heat insulating region can be formed by forming the gap. In addition, since this gap is formed to have a length that allows the temperature boundary layer Bt to be maintained without interruption in the flow direction of the cooled air a, frost is formed at the end of the plate-shaped heat dissipation member 40 that is interrupted by this gap. Suppressed.
  • the heat insulating zone 42 (42b) constitutes a heat insulating zone made of a material having a low thermal conductivity. The surface of this adiabatic region is formed smooth so that the air to be cooled a is not disturbed.
  • the defrost unit 18 can maintain the surface temperature of frost on the heat transfer tubes 16 for each heat transfer tube group at a temperature of less than 0 ° C. and higher than the temperature of the cooled air a.
  • the defrost fluid supply part 50 which can supply a defrost fluid is provided.
  • the frost layer adhered to the adhesion surface is sublimated, Can be scattered.
  • the temperature of the surface on which frost adheres is maintained at -2 ° C to -5 ° C.
  • the defrost fluid supply unit 50 supplies the defrost fluid capable of maintaining the frost adhering surface temperature within the above temperature range to the heat transfer tube group performing the defrost operation, so that the heat transfer surface Sublimation defrost that sublimes and removes the adhered frost becomes possible.
  • the defrost fluid supply unit 50 includes a buffer tank 44 provided in the defrost flow passage 34.
  • the buffer tank 44 includes a heating unit 46 for heating the defrost fluid stored in the buffer tank 44, and the control unit 48 controls the opening degree of the pressure adjusting valve 36 and controls the heating unit 46.
  • the state of the temperature, pressure, etc. of the cooling medium supplied to the heat transfer tube group during the defrost operation is controlled to a state in which the frost adhesion surface temperature can be maintained below 0 ° C. and higher than the temperature of the cooled air a. ..
  • a plurality of heat transfer tube groups may be arranged in the flow direction of the cooled air a.
  • two heat transfer tube groups may be arranged in the flow direction of the cooled air a.
  • a plurality of heat transfer tube groups may be arranged so as to be vertically stacked.
  • a plurality of heat transfer tube groups Ta, Tb, and Tc may be formed in an arc shape so as to surround the fan 14 with the fan 14 as the center.
  • the plurality of heat transfer tube groups Ta, Tb, and Tc are arranged in this order from the upstream side of the cooled air a.
  • the heat transfer tube group is divided into a plurality of flow path areas Fa, Fb, and Fc, and each flow path area is configured by a plurality of heat transfer tube groups Ta, Tb, and Tc.
  • the fan 14 may be arranged upstream of the plurality of heat transfer tube groups and operated as a push-in type fan.
  • the defrosting method of the heat exchanger relates to the defrosting method using the heat exchanger 10 shown in FIG. That is, the heat exchanger 10 includes a cooling air passage through which the cooled air a flows, and a direction (arrow b direction / arrow b direction / A plurality of heat transfer tubes 16 extending along the first direction) and a defrost unit 18 for defrosting a defrost target tube among the plurality of heat transfer tubes 16 are provided.
  • the plurality of heat transfer tubes 16 are formed by the plurality of heat transfer tubes 16 arranged along a direction (arrow a direction) of the cooled air a and a direction (arrow c direction / second direction) orthogonal to the arrow b direction.
  • a plurality of rows of heat transfer tubes are arranged so as to be aligned in the flow direction of the cooled air a.
  • the cooling air flow path includes a plurality of flow path areas Fa, Fb, and Fc arranged in the direction of arrow c, and the plurality of heat transfer tubes 16 respectively correspond to the plurality of flow path areas and within the same flow path area.
  • a plurality of heat transfer tube groups Ta, Tb and Tc formed by a plurality of heat transfer tubes 16 belonging to two or more heat transfer tube rows adjacent to each other in the flow direction of the cooled air a are included.
  • one or more heat transfer tube groups among a plurality of heat transfer tube groups Ta, Tb, and Tc are selected as defrosting target tubes, and the one or more heat transfer tube groups are sequentially selected.
  • Each step is repeatedly defrosted (defrosting step S10).
  • the heat transfer surfaces of the heat transfer tubes 16 are cooled by repeatedly defrosting one or more heat transfer tube groups among the plurality of heat transfer tube groups Ta, Tb, Tc, ...
  • the defrost unit 18 includes only the heat transfer tube row on the most upstream side in the flow direction among the plurality of heat transfer tube rows (in this embodiment, the heat transfer tube rows belonging to the heat transfer tube group Ta).
  • the defrosting step S10 is configured to selectively defrost as the defrosting target tube.
  • only the heat transfer tube row on the most upstream side in the flow direction of the cooled air a (heat transfer tube row belonging to the heat transfer tube group Ta) is set as the defrosting target tube.
  • Defrost selectively (step S10a). As described above, by selectively defrosting only the most upstream heat transfer tube row in the flow direction of the cooled air a as the defrosting target tube, it is possible to suppress the growth of frost formation on the most upstream heat transfer tube array.
  • the time is set, and the defrost execution time interval of each heat transfer tube group is set from this one defrost time.
  • the limit time is set to the upper limit value at which the flow of the cooled air a does not close the gaps between the plate-shaped heat radiating members 40, so that between the plate-shaped heat radiating members 40 in each heat transfer tube group.
  • the defrost operation can be performed so that the passage of the cooled air a is not blocked.
  • the defrost execution time interval of each of the plurality of heat transfer tube groups is set longer for the heat transfer tube group arranged on the downstream side in the flow direction.
  • the growth of frost tends to be slower in the heat transfer tube group on the downstream side in the flow direction of the cooled air a.
  • the defrost operation time interval is set to be longer in the heat transfer tube group on the downstream side in the flow direction of the cooled air a, so that the frequency of defrost operation can be reduced, whereby heat exchange during defrost operation is performed. It is possible to suppress a decrease in cooling efficiency of the container 10.
  • the defrosting fluid that can maintain the frost attachment surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled is transferred to the heat transfer tubes 16 of the heat transfer tube group that is the defrosting target.
  • the frost adhered to the heat transfer tube 16 is sublimated by the retained heat of the defrost fluid (sublimation defrost step S10b).
  • the defrost fluid for example, a high-temperature refrigerant gas on the compressor discharge side of the refrigerator 20 is used. According to this embodiment, by supplying the defrost fluid capable of maintaining the frost attachment surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled to the heat transfer tube 16 performing the defrost operation, Sublimation defrost that sublimes and removes frost adhering to the surface becomes possible.
  • the temperature difference between the air to be cooled a and the defrost fluid is set to be smaller as the heat transfer tube group is arranged on the downstream side in the flow direction of the air to be cooled a.
  • the smaller the temperature difference between the cooled gas and the defrost fluid the less the frost removal effect, but the slower the frost layer grows toward the wake side. Therefore, the cooling efficiency of the heat exchanger 10 can be suppressed from decreasing while maintaining the frost removal effect by making the temperature difference smaller toward the downstream side in the flow direction where the growth of frost is slow.
  • Step S10 when the heat transfer tube group to be defrosted is arranged on the upstream side in the flow direction of the cooled air a, the fan 14 is rotated in the reverse direction to reverse the flow direction (backflow).
  • Step S10c As shown in FIG. 1, by providing the fan 14 (14a, 14b, 14c) for each of the flow passage regions Fa, Fb, and Fc, the flow of the cooled air a can be reversed only in the heat transfer tube group to be defrosted. .
  • the cooled air a by reversing the flow direction of the cooled air a during the defrost operation, it is possible to suppress the re-adhesion of the frost separated from the adhering surface to the heat transfer tube 16 on the downstream side, and also to the upstream side. It is possible to process with. Further, the frost attached to the tip portion can be efficiently removed. Furthermore, the cooled air a heated by the defrost heat source once returns to the upstream side, is mixed, and flows into another heat transfer tube group, so that temperature unevenness on the downstream side of the heat exchanger 10 can be suppressed.
  • the thermal efficiency of the heat exchanger due to the defrost operation is reduced while preventing the cooled gas from being blocked on the heat transfer surface. It is possible to suppress and prevent the frost separated from the adhesion surface during defrosting from re-adhering to the heat transfer surface. Further, it is possible to realize a defrosting device capable of efficiently operating the cooling device while suppressing wasteful defrosting heating of the heat exchanger.
  • Heat Exchanger 12 Casing 14 (14a, 14b, 14c) Fan 16 Heat Transfer Tube 18 Defrost Unit 20 Refrigerator 22 Refrigerant Circuit 24 Compressor 26 Condenser 28 Receiver 30 Expansion Valve 32 Check Valve 34 Defrost Flow Path 36 Pressure Control Valve 38 Capillary tube 40 Plate-shaped heat radiating member 40a Tip portion 42 (42a, 42b) Adiabatic area 44 Buffer tank 46 Heating part 47, 49 Solenoid valve 48 Control part 50 Defrost fluid supply part Bt Temperature boundary layer Fa, Fb, Fc Flow path area Ta, Tb, Tc Heat transfer tube group a Cooled air

Abstract

This heat exchanger comprises: a plurality of heat transfer pipes that extend along a first direction orthogonal to a flow direction for a gas to be cooled; and a defrosting unit for defrosting pipes to be defrosted among the plurality of heat transfer pipes. A plurality of heat transfer pipe rows are arranged lined up in the flow direction, said heat transfer pipe rows being formed by the plurality of heat transfer pipes being arranged along a second direction orthogonal to the flow direction and the first direction. A gas flow path includes a plurality of flow path areas lined up in the second direction. The plurality of heat transfer pipes correspond to each of the plurality of flow path areas and include a plurality of heat transfer pipe groups formed by a plurality of heat transfer pipes belonging to at least two heat transfer pipe rows that are mutually adjacent in the flow direction inside the same flow path area. The defrosting unit is configured so as to selectively defrost, as pipes to be defrosted, pipes in at least one heat transfer pipe group.

Description

熱交換器及び熱交換器のデフロスト方法Heat exchanger and defrosting method for heat exchanger
　本開示は、熱交換器及び熱交換器のデフロスト方法に関する。 The present disclosure relates to a heat exchanger and a defrosting method for the heat exchanger.
　冷凍庫やフリーザに設けられるエアクーラなどの熱交換器にフィンチューブ式熱交換器が用いられる。フィンチューブ式熱交換器は放熱フィンなどに霜が付きやすく、フィン間に形成された霜層によって空気流が閉塞されるため、頻繁にデフロスト運転が必要になる。そこで、本発明者等は、フィンや伝熱管に付着した霜を昇華して除去するデフロスト方法を提案している（特許文献１）。このデフロスト方法は、着霜を昇華させ空気流に乗って飛散させるため、融解水が発生しない。従って、融解水を熱交換器から取り除く作業が不要になると共に、エアクーラの運転を継続しながらデフロストできる利点がある。 Fin-tube heat exchangers are used as heat exchangers such as air coolers installed in freezers and freezers. In the fin tube type heat exchanger, radiating fins are likely to be covered with frost, and the frost layer formed between the fins blocks the air flow, so that frequent defrost operation is required. Therefore, the present inventors have proposed a defrosting method of sublimating and removing frost attached to the fins and the heat transfer tubes (Patent Document 1). In this defrost method, frost is sublimated and scattered on the air flow, so that no molten water is generated. Therefore, there is an advantage that the work of removing the melted water from the heat exchanger becomes unnecessary and defrosting can be performed while the operation of the air cooler is continued.
国際公開第２０１７／１７５４１１号International Publication No. 2017/175411
　しかし、上記昇華デフロスト方法は、霜が付着した付着面を０℃未満で被冷却空気より高い温度に加温する必要があるため、デフロスト時に加えられる熱量によって稼働中の熱交換器の熱効率が低下するという問題がある。また、一旦付着面から剥離した霜が空気流に乗って下流側の伝熱管やフィンに再付着してしまうという問題がある。
　また、複数の区画ごとにデフロストを行なうにしても、熱交換器の被冷却気体の流れ方向において着霜量が異なるため、熱交換器全体の霜が完全に除去されるまでデフロスト運転を続ける必要がある。そのため、冷却装置の運転効率を悪くするという問題がある。 However, in the above sublimation defrosting method, since it is necessary to heat the frost-attached surface to a temperature lower than 0 ° C. and higher than the air to be cooled, the heat efficiency of the heat exchanger in operation is reduced due to the amount of heat applied during defrosting. There is a problem of doing. In addition, there is a problem that the frost that has once separated from the attachment surface rides on the air flow and is reattached to the heat transfer tubes and fins on the downstream side.
Even if defrosting is performed for each of a plurality of sections, the amount of frost is different in the flow direction of the gas to be cooled in the heat exchanger, so it is necessary to continue the defrosting operation until the frost in the entire heat exchanger is completely removed. There is. Therefore, there is a problem that the operating efficiency of the cooling device is deteriorated.
　一実施形態は、デフロスト運転による熱交換器の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が下流側の伝熱面に再付着するのを抑制可能であって、さらには、熱交換器の無駄なデフロスト加熱を抑えながら効率的な冷却装置の運転が可能なデフロスト手段を提案することを目的とする。 One embodiment, it is possible to suppress the decrease in thermal efficiency of the heat exchanger due to the defrost operation, and to prevent the frost separated from the adhesion surface during defrosting from re-adhering to the heat transfer surface on the downstream side, and further, It is an object of the present invention to propose a defrosting device capable of efficiently operating a cooling device while suppressing wasteful defrosting heating of a heat exchanger.
　（１）一実施形態に係る熱交換器は、
　被冷却気体が流れる気体流路と、
　前記気体流路内において、前記気体流路における前記被冷却気体の流れ方向と直交する第１方向に沿って延在する複数の伝熱管と、
　前記複数の伝熱管のうちデフロスト対象管をデフロストするためのデフロストユニットと、
を備え、
　前記複数の伝熱管は、前記流れ方向および前記第１方向に直交する第２方向に沿って配列された複数の前記伝熱管により形成される伝熱管列が、前記流れ方向に複数並ぶように配列され、
　前記気体流路は、前記第２方向に並ぶ複数の流路領域を含み、
　前記複数の伝熱管は、前記複数の流路領域に夫々対応し、かつ、同一の前記流路領域内において前記流れ方向にて互いに隣接する２以上の前記伝熱管列に属する複数の前記伝熱管により形成される複数の伝熱管グループを含み、
　前記デフロストユニットは、前記複数の伝熱管グループのうち１以上の前記伝熱管グループの前記伝熱管を前記デフロスト対象管として選択的にデフロストを行うように構成される。 (1) The heat exchanger according to one embodiment is
A gas flow path through which the cooled gas flows,
In the gas flow path, a plurality of heat transfer tubes extending along a first direction orthogonal to the flow direction of the gas to be cooled in the gas flow path,
A defrost unit for defrosting the defrost target pipe among the plurality of heat transfer tubes,
Equipped with
The plurality of heat transfer tubes are arranged such that a plurality of heat transfer tube rows formed by the plurality of heat transfer tubes arranged along a second direction orthogonal to the flow direction and the first direction are arranged in the flow direction. Was
The gas flow path includes a plurality of flow path regions arranged in the second direction,
The plurality of heat transfer tubes respectively correspond to the plurality of flow path areas and belong to two or more heat transfer tube rows adjacent to each other in the same flow path area in the flow direction. Including a plurality of heat transfer tube groups formed by
The defrost unit is configured to selectively defrost the heat transfer tubes of one or more heat transfer tube groups of the plurality of heat transfer tube groups as the defrosting target tubes.
　上記（１）の構成において、気体流路に設けられる複数の伝熱管は、複数の伝熱管グループで構成され、上記デフロストユニットによって、１以上の伝熱管グループを構成する伝熱管がデフロスト対象管として選択的にデフロストされる。伝熱管グループ毎に霜の付着及び成長の度合いは異なるため、成長した霜層によって気体流路が閉塞される時間は、伝熱管グループ毎に異なる。そこで、各伝熱管グループをデフロストする順序を適宜選択することで、伝熱管が形成する伝熱面における気体流路の閉塞を防止しながら、デフロスト運転による熱交換器の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が伝熱面に再付着するのを抑制できる。さらには、熱交換器の無駄なデフロスト加熱を抑えながら効率的な冷却装置の運転が可能となる。 In the configuration of (1) above, the plurality of heat transfer tubes provided in the gas flow path are configured of a plurality of heat transfer tube groups, and the heat transfer tubes that form one or more heat transfer tube groups by the defrost unit serve as defrost target tubes. Defrosted selectively. Since the degree of adhesion and growth of frost is different for each heat transfer tube group, the time when the gas flow path is blocked by the grown frost layer is different for each heat transfer tube group. Therefore, by appropriately selecting the order of defrosting each heat transfer tube group, while preventing the blockage of the gas flow path in the heat transfer surface formed by the heat transfer tube, while suppressing the decrease in the thermal efficiency of the heat exchanger due to defrost operation, In addition, it is possible to prevent the frost separated from the adhesion surface during defrosting from re-adhering to the heat transfer surface. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger.
　（２）一実施形態では、前記（１）の構成において、
　前記デフロストユニットは、複数の前記伝熱管列のうち前記流れ方向最上流側の前記伝熱管列のみを前記デフロスト対象管として選択的にデフロストするように構成される。
　流れ方向最上流側伝熱管の伝熱面は熱伝達率が高く、かつ被冷却気体に含まれるミスト（液体及び固体）が慣性力により最上流側伝熱管やフィンの先端部分に多く衝突するために、これらの部位に集中して着霜が生じ、かつ着霜の成長が早くなる現象が起こる。
　上記（２）の構成によれば、被冷却気体の流れ方向最上流側の伝熱管列のみをデフロスト対象管として選択的にデフロストすることで、最上流側伝熱管列を優先してデフロストでき、これによって、最上流側の伝熱管列の着霜の成長を抑制できる。 (2) In one embodiment, in the configuration of (1) above,
The defrost unit is configured to selectively defrost only the heat transfer tube row on the most upstream side in the flow direction of the plurality of heat transfer tube rows as the defrosting target tube.
The heat transfer surface of the most upstream heat transfer tube in the flow direction has a high heat transfer coefficient, and the mist (liquid and solid) contained in the gas to be cooled collides with the most upstream heat transfer tube and the tip of the fin due to inertial force. In addition, a phenomenon occurs in which frost is concentrated on these parts and the growth of frost is accelerated.
According to the configuration of (2), by selectively defrosting only the heat transfer tube row on the most upstream side in the flow direction of the gas to be cooled as the defrosting target tube, the most upstream heat transfer tube row can be preferentially defrosted, As a result, it is possible to suppress the growth of frost on the heat transfer tube row on the most upstream side.
　（３）一実施形態では、前記（１）又は（２）の構成において、
　前記複数の伝熱管が貫通又は接触するように前記気体流路内にて前記流れ方向に沿って設けられる板状放熱部材を備える。
　上記（３）の構成によれば、上記板状放熱部材を備えることで伝熱面積が増加するため、熱交換器の伝熱性能を向上できる。また、上記板状放熱部材は被冷却気体の流れ方向に沿って設けられるので、被冷却気体の乱れを抑制できる。被冷却気体の乱れが抑制された板状放熱部材の表面には、板状放熱部材の表面に近づくほど温度が徐々に低くなる温度境界層が形成される。この温度境界層の形成によって被冷却気体と板状放熱部材間の熱伝達率は抑制されるため、板状放熱部材の表面に形成される霜層の成長を抑制できる。逆に温度境界層を乱すような構成（例えばルーバーフィン等）とすると、熱伝達率が上昇し霜の成長が促進される。これを利用して、霜を成長させたい場所、させたくない場所、つまり各所の霜の成長量を，熱交換量やデフロスト間隔と関連させて最適に設計することができる。 (3) In one embodiment, in the configuration of (1) or (2) above,
A plate-shaped heat radiating member is provided in the gas flow path along the flow direction so that the plurality of heat transfer tubes penetrate or contact each other.
According to the configuration of (3), since the heat transfer area is increased by including the plate-shaped heat dissipation member, the heat transfer performance of the heat exchanger can be improved. Moreover, since the plate-shaped heat dissipation member is provided along the flow direction of the gas to be cooled, it is possible to suppress the turbulence of the gas to be cooled. A temperature boundary layer is formed on the surface of the plate-shaped heat dissipation member in which the turbulence of the gas to be cooled is suppressed, and the temperature gradually decreases toward the surface of the plate-shaped heat dissipation member. Since the formation of the temperature boundary layer suppresses the heat transfer coefficient between the gas to be cooled and the plate-shaped heat dissipation member, it is possible to suppress the growth of the frost layer formed on the surface of the plate-shaped heat dissipation member. On the contrary, if the temperature boundary layer is disturbed (for example, a louver fin or the like), the heat transfer coefficient is increased and the growth of frost is promoted. By utilizing this, it is possible to optimally design a place where frost is to be grown or a place where frost is not desired, that is, a growth amount of frost in each place in association with a heat exchange amount and a defrosting interval.
　（４）一実施形態では、前記（３）の構成において、
　前記板状放熱部材は、前記流れ方向に沿って前記伝熱管グループ毎に互いに温度境界層を乱さない間隔を置いて複数並列に配置される。
　上記（４）の構成によれば、複数の板状放熱部材が配置されるため、伝熱面積を増加でき伝熱性能を向上できる。また、板状放熱部材は被冷却気体の流れ方向に沿って並列配置されるため、被冷却気体の乱れを抑制でき、これによって、隣り合う伝熱管グループ同士の板状放熱部材間の空隙の温度境界層が維持され、その空隙に面する板状放熱部材の流れ方向上流側の端部の霜層の成長を抑制することで、着霜の集中を抑制し、部分閉塞を抑制できる。また、この構成によれば、デフロスト時に隣り合う伝熱管グループの温度差があっても、この空隙が断熱材の役割を果たすため、隣りの伝熱管グループへの影響を抑制し、熱交換効率の低下を抑制できる。 (4) In one embodiment, in the configuration of (3) above,
A plurality of the plate-shaped heat dissipation members are arranged in parallel along the flow direction at intervals that do not disturb the temperature boundary layer for each heat transfer tube group.
According to the configuration of (4), since the plurality of plate-shaped heat dissipation members are arranged, the heat transfer area can be increased and the heat transfer performance can be improved. Further, since the plate-shaped heat radiating members are arranged in parallel along the flow direction of the gas to be cooled, the turbulence of the gas to be cooled can be suppressed, whereby the temperature of the gap between the plate-shaped heat radiating members of the adjacent heat transfer tube groups can be suppressed. The boundary layer is maintained, and the growth of the frost layer at the upstream end in the flow direction of the plate-shaped heat dissipation member facing the gap is suppressed, whereby the concentration of frost formation can be suppressed and partial blockage can be suppressed. Further, according to this configuration, even if there is a temperature difference between the adjacent heat transfer tube groups at the time of defrosting, since this void serves as a heat insulating material, the influence on the adjacent heat transfer tube groups is suppressed, and the heat exchange efficiency is improved. The decrease can be suppressed.
　（５）一実施形態では、前記（３）又は（４）の構成において、
　前記板状放熱部材は、前記流れ方向最上流側に設けられた前記伝熱管から前記流れ方向で前記伝熱管に隣接する１個以上の前記伝熱管まで延在する。
　板状放熱部材の先端部分は、温度境界層の層厚が薄いため、被冷却気体と板状放熱部材間の熱伝達率が促進され、着霜の成長が早くなる。そこで板状放熱部材を下流側の伝熱管まで延在させることで、新たな先端部分の形成をなくし、先端部分以外の領域では温度境界層を存在させる。これによって、先端部分以外の領域で着霜の成長を抑制できる。 (5) In one embodiment, in the configuration of (3) or (4) above,
The plate-shaped heat dissipation member extends from the heat transfer tube provided on the most upstream side in the flow direction to one or more heat transfer tubes adjacent to the heat transfer tube in the flow direction.
Since the temperature boundary layer is thin at the tip end portion of the plate-shaped heat dissipation member, the heat transfer coefficient between the gas to be cooled and the plate-shaped heat dissipation member is promoted, and the growth of frost is accelerated. Therefore, by extending the plate-shaped heat dissipation member to the heat transfer tube on the downstream side, the formation of a new tip portion is eliminated, and the temperature boundary layer is present in the area other than the tip portion. Thereby, the growth of frost can be suppressed in the area other than the tip portion.
　（６）一実施形態では、前記（３）～（５）の何れかの構成において、
　前記板状放熱部材は、前記流れ方向で２個以上の前記伝熱管グループに跨るように配置されると共に、前記伝熱管グループ間の領域に前記伝熱管グループ間の伝熱を抑制する断熱域を有する。
　上記（６）の構成によれば、板状放熱部材は、伝熱管グループ間の領域に伝熱管グループ間の伝熱を抑制する断熱域を有するため、該断熱域の一方側の伝熱管グループが通常の冷却運転を継続し、他方側の伝熱管グループがデフロスト運転を行うとき、デフロスト運転で加えられる熱が冷却運転中の伝熱管グループに伝わって熱交換器の冷却効率を低下させるのを抑制できる。 (6) In one embodiment, in any one of the configurations (3) to (5) above,
The plate-shaped heat dissipating member is disposed so as to straddle two or more heat transfer tube groups in the flow direction, and has a heat insulating region in a region between the heat transfer tube groups that suppresses heat transfer between the heat transfer tube groups. Have.
According to the configuration of the above (6), the plate-shaped heat dissipation member has the heat insulating region for suppressing heat transfer between the heat transfer pipe groups in the region between the heat transfer pipe groups. When the normal cooling operation is continued and the heat transfer tube group on the other side performs defrost operation, the heat added in the defrost operation is prevented from being transferred to the heat transfer tube group during the cooling operation and lowering the cooling efficiency of the heat exchanger. it can.
　（７）一実施形態では、前記（１）～（６）の何れかの構成において、
　前記デフロストユニットは、前記伝熱管グループ毎に前記伝熱管に霜の付着面温度を０℃未満でかつ前記被冷却気体の温度より高い温度に維持可能なデフロスト流体を供給可能な一つ又は複数のデフロスト流体供給部を含む。
　上記（７）の構成によれば、上記デフロスト流体供給部によって、デフロスト運転を行う伝熱管グループに対して、霜の付着面温度を０℃未満でかつ被冷却気体の温度より高い温度に維持可能なデフロスト流体を供給することで、付着面に付着した霜を昇華させて除去する昇華デフロストが可能になる。なお、デフロスト流体供給部は必要に応じて複数設けてもよい。 (7) In one embodiment, in any one of the configurations (1) to (6) above,
The defrost unit may supply, for each heat transfer tube group, one or more defrost fluids capable of maintaining the frost adhesion surface temperature of the heat transfer tubes below 0 ° C. and higher than the temperature of the gas to be cooled. Includes a defrost fluid supply.
According to the above configuration (7), the defrost fluid supply unit can maintain the frost adhesion surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled for the heat transfer tube group performing the defrost operation. By supplying such a defrosting fluid, sublimation defrosting that sublimates and removes the frost adhering to the adhering surface becomes possible. Note that a plurality of defrost fluid supply units may be provided as needed.
　（８）一実施形態に係る熱交換器のデフロスト方法は、
　被冷却気体が流れる気体流路と、前記気体流路内において、前記気体流路における前記被冷却気体の流れ方向と直交する第１方向に沿って延在する複数の伝熱管と、前記複数の伝熱管のうちデフロスト対象管をデフロストするためのデフロストユニットと、を備え、前記複数の伝熱管は、前記流れ方向および前記第１方向に直交する第２方向に沿って配列された複数の前記伝熱管により形成される伝熱管列が、前記被冷却気体の前記流れ方向に複数並ぶように配列され、前記気体流路は、前記第２方向に並ぶ複数の流路領域を含み、前記複数の伝熱管は、前記複数の流路領域に夫々対応し、かつ、同一の前記流路領域内において前記流れ方向にて互いに隣接する２以上の前記伝熱管列に属する複数の前記伝熱管により形成される複数の伝熱管グループを含む熱交換器のデフロスト方法であって、
　前記複数の伝熱管グループのうち１以上の前記伝熱管グループをデフロスト対象管として選択し、該１以上の伝熱管グループ毎に順々に繰り返しデフロストするデフロストステップを備える。 (8) The defrosting method for the heat exchanger according to the embodiment is
A gas flow path through which the gas to be cooled flows, a plurality of heat transfer tubes extending in the gas flow path along a first direction orthogonal to the flow direction of the gas to be cooled in the gas flow path, and the plurality of heat transfer tubes A defrost unit for defrosting a defrost target tube among the heat transfer tubes, wherein the plurality of heat transfer tubes are arranged along a second direction orthogonal to the flow direction and the first direction. A row of heat transfer tubes formed by heat tubes is arranged so as to be lined up in the flow direction of the cooled gas, and the gas flow path includes a plurality of flow path areas lined up in the second direction. The heat pipes are formed by the plurality of heat transfer tubes that respectively correspond to the plurality of flow path regions and that belong to two or more heat transfer tube rows that are adjacent to each other in the flow direction in the same flow path region. A defrosting method for a heat exchanger including a plurality of heat transfer tube groups, comprising:
A defrosting step of selecting one or more heat transfer tube groups from the plurality of heat transfer tube groups as a defrosting target tube and sequentially defrosting each of the one or more heat transfer tube groups in sequence is provided.
　上記（８）の方法において、デフロストステップでは、複数の伝熱管グループのうち１以上の伝熱管グループをデフロスト対象管として選択し、該１以上の伝熱管グループ毎に順々に繰り返しデフロストする。そこで、各伝熱管グループをデフロストする順序を適宜選択することで、霜層による伝熱面周囲の被冷却気体の閉塞を防止しながら、デフロスト時に加えられる熱による熱交換器の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が下流側の伝熱面に再付着するのを抑制できる。さらには、熱交換器の無駄なデフロスト加熱を抑えながら効率的な冷却装置の運転が可能となる。 In the method of (8) above, in the defrosting step, one or more heat transfer tube groups are selected from the plurality of heat transfer tube groups as defrosting target tubes, and defrosting is sequentially repeated for each of the one or more heat transfer tube groups. Therefore, by appropriately selecting the order of defrosting each heat transfer tube group, it is possible to prevent the cooling gas around the heat transfer surface from being blocked by the frost layer while suppressing the decrease in the heat efficiency of the heat exchanger due to the heat added during defrosting. In addition, it is possible to prevent the frost separated from the adhering surface during defrosting from adhering again to the heat transfer surface on the downstream side. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger.
　（９）一実施形態では、前記（８）の方法において、
　前記デフロストユニットは、複数の前記伝熱管列のうち前記流れ方向最上流側の前記伝熱管列のみを前記デフロスト対象管として選択的にデフロストするように構成され、
　前記デフロストステップは、前記流れ方向最上流側の前記伝熱管列のみを前記デフロスト対象管として選択的にデフロストするステップを含む。
　上記（９）の方法によれば、デフロストステップにおいて、被冷却気体の流れ方向最上流側の伝熱管列のみをデフロスト対象管として選択的にデフロストすることで、最上流側伝熱管列を優先してデフロストでき、最上流側伝熱管列の着霜の成長を抑制できる。　 (9) In one embodiment, in the method of (8) above,
The defrost unit is configured to selectively defrost only the heat transfer tube row on the most upstream side in the flow direction among the plurality of heat transfer tube rows as the defrosting target tube,
The defrosting step includes a step of selectively defrosting only the heat transfer tube row on the most upstream side in the flow direction as the defrosting target tube.
According to the above method (9), in the defrosting step, by selectively defrosting only the heat transfer tube row on the most upstream side in the flow direction of the gas to be cooled as the defrosting target tube, the heat transfer tube row on the most upstream side is given priority. Can be defrosted, and the growth of frost on the most upstream heat transfer tube row can be suppressed.
　（１０）一実施形態では、前記（８）又は（９）の方法において、
　前記デフロストステップにおいて、
　前記伝熱管の少なくとも一部に付着する着霜量が許容値の上限に達する限界時間に合わせて、すべての前記伝熱管グループを１回デフロストするに要する１デフロスト時間を設定し、該１デフロスト時間から前記伝熱管グループの各々のデフロスト実施時間間隔を設定する。
　上記（１０）の方法によれば、上記限界時間を被冷却気体の流れが閉塞しない上限値に設定することで、各伝熱管グループにおいて被冷却気体の閉塞が生じないようにデフロスト運転を実施できる。 (10) In one embodiment, in the method of (8) or (9) above,
In the defrosting step,
The 1 defrost time required to defrost all the heat transfer tube groups once is set in accordance with the limit time when the amount of frost adhering to at least a part of the heat transfer tubes reaches the upper limit of the allowable value, and the 1 defrost time is set. To set a defrost execution time interval for each of the heat transfer tube groups.
According to the above method (10), by setting the limit time to the upper limit value at which the flow of the gas to be cooled is not blocked, the defrost operation can be performed so that the gas to be cooled is not blocked in each heat transfer tube group. ..
　（１１）一実施形態では、前記（１０）の方法において、
　前記複数の伝熱管グループの各々の前記デフロスト実施時間間隔は、前記流れ方向下流側に配置された前記伝熱管グループほど長く設定される。
　被冷却気体の流れ方向下流側ほど着霜の成長は遅くなる傾向にある。そこで、デフロスト実施時間間隔を着霜の成長が遅い流れ方向下流側の伝熱管グループほど長く設定することで、デフロスト運転の頻度を少なくでき、これによって、デフロスト運転による冷却効率の低下を抑制できる。 (11) In one embodiment, in the method of (10) above,
The defrost execution time interval of each of the plurality of heat transfer tube groups is set to be longer for the heat transfer tube group arranged on the downstream side in the flow direction.
The growth of frost tends to be slower on the downstream side in the flow direction of the cooled gas. Therefore, by setting the defrosting time interval to be longer for the heat transfer tube group on the downstream side in the flow direction in which frost growth is slower, the frequency of defrosting operation can be reduced, and thereby the reduction in cooling efficiency due to defrosting operation can be suppressed.
　（１２）一実施形態では、前記（８）～（１１）の何れかの方法において、
　前記デフロストステップにおいて、
　霜の付着面温度を０℃未満でかつ前記被冷却気体の温度より高い温度に維持可能なデフロスト流体を前記伝熱管に供給し、該デフロスト流体の保有熱によって前記伝熱管に付着した霜を昇華させる。
　上記（１２）の方法によれば、デフロスト運転を行う伝熱管に対して、霜の付着面温度を０℃未満でかつ被冷却気体の温度より高い温度に維持可能なデフロスト流体を供給することで、付着面に付着した霜を昇華させて除去する昇華デフロストが可能になる。 (12) In one embodiment, in the method according to any one of (8) to (11) above,
In the defrosting step,
A defrost fluid capable of maintaining the surface temperature of the frost below 0 ° C. and higher than the temperature of the gas to be cooled is supplied to the heat transfer tube, and the frost attached to the heat transfer tube is sublimated by the heat of the defrost fluid. Let
According to the above method (12), the defrost fluid capable of maintaining the frost adhesion surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled is supplied to the heat transfer tube performing the defrost operation. , Sublimation defrost that sublimes and removes the frost adhering to the adhering surface becomes possible.
　（１３）一実施形態では、前記（１２）の方法において、
　前記デフロストステップにおいて、
　前記複数の伝熱管グループの各々において、前記流れ方向下流側に配置された前記伝熱管グループほど前記被冷却気体と前記デフロスト流体との温度差は小さく設定される。
　被冷却気体とデフロスト流体との温度差が小さいほど、着霜の除去効果は減少するが、冷却運転中の熱交換器の熱効率の低下を抑制できる。従って、着霜の成長が遅い流れ方向下流側ほど上記温度差を小さくすることで、着霜による気体流路の閉塞を防止しながら、熱交換器の冷却効率の低下を抑制できる。 (13) In one embodiment, in the method (12) above,
In the defrosting step,
In each of the plurality of heat transfer tube groups, the temperature difference between the gas to be cooled and the defrost fluid is set to be smaller as the heat transfer tube group is arranged on the downstream side in the flow direction.
The smaller the temperature difference between the gas to be cooled and the defrost fluid, the smaller the effect of removing frost, but the lowering of the thermal efficiency of the heat exchanger during the cooling operation can be suppressed. Therefore, by making the temperature difference smaller toward the downstream side in the flow direction where frost formation is slower, it is possible to prevent the gas flow passage from being blocked due to frost formation, while suppressing a decrease in cooling efficiency of the heat exchanger.
　（１４）一実施形態では、前記（８）～（１３）の何れかの方法において、
　前記デフロストステップにおいて、
　前記流れ方向上流側に配置された前記伝熱管グループがデフロスト対象となったとき、前記流れ方向を逆向きにする。
　上記（１４）の方法によれば、流れ方向上流側に配置された伝熱管グループをデフロストするとき、被冷却気体の流れ方向を逆向きにすることで、付着面から剥離した霜が下流側の伝熱管に再付着するのを抑制できると共に、上流側で処理することを可能とする。また、先端部分に付着した霜を効率的に除去できる。さらに、デフロスト熱源によって昇温した被冷却気体が，一度上流側に戻り混合され、他の伝熱管グループに流入するため、熱交換器後流の温度むらを抑制できる。 (14) In one embodiment, in the method according to any one of (8) to (13) above,
In the defrosting step,
When the heat transfer tube group arranged on the upstream side in the flow direction is subjected to defrosting, the flow direction is reversed.
According to the above method (14), when defrosting the heat transfer tube group arranged on the upstream side in the flow direction, the flow direction of the gas to be cooled is reversed so that the frost separated from the adhering surface is on the downstream side. It is possible to suppress re-adhesion to the heat transfer tube, and it is possible to perform processing on the upstream side. Moreover, the frost adhering to the tip portion can be efficiently removed. Further, the cooled gas whose temperature has been raised by the defrost heat source once returns to the upstream side, is mixed, and flows into another heat transfer tube group, so that the temperature unevenness in the downstream of the heat exchanger can be suppressed.
　幾つかの実施形態によれば、伝熱面における気体流路の閉塞を防止しながら、デフロスト運転による熱交換器の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が伝熱面に再付着するのを抑制できる。さらには、熱交換器の無駄なデフロスト加熱を抑えながら効率的な冷却装置の運転が可能となる。 According to some embodiments, while preventing the gas flow passage from being blocked on the heat transfer surface, the reduction of the thermal efficiency of the heat exchanger due to the defrost operation is suppressed, and the frost separated from the adhering surface during the defrost operation causes the heat transfer surface to be defrosted. It is possible to suppress reattachment to the. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger.
一実施形態に係る熱交換器の斜視図である。It is a perspective view of the heat exchanger which concerns on one Embodiment. 一実施形態に係る冷凍ユニット及びデフロストユニットの系統図である。It is a systematic diagram of a refrigeration unit and a defrost unit concerning one embodiment. 一実施形態に係る熱交換器の平面図である。It is a top view of the heat exchanger which concerns on one Embodiment. 一実施形態に係る板状放熱部材の平面図である。It is a top view of the plate-shaped heat dissipation member which concerns on one Embodiment. 一実施形態に係る板状放熱部材の平面図である。It is a top view of the plate-shaped heat dissipation member which concerns on one Embodiment. 一実施形態に係る熱交換器の平面視による模式図である。It is a schematic diagram by a plan view of a heat exchanger according to one embodiment. 一実施形態に係る熱交換器の平面視による模式図である。It is a schematic diagram by a plan view of a heat exchanger according to one embodiment. 一実施形態に係る熱交換器のデフロスト方法の工程図である。It is process drawing of the defrosting method of the heat exchanger which concerns on one Embodiment.
　以下、添付図面を参照して本発明の幾つかの実施形態について説明する。ただし、実施形態として記載され又は図面に示されている構成部品の寸法、材質、形状、その相対的配置等は、本発明の範囲をこれに限定する趣旨ではなく、単なる説明例にすぎない。
　例えば、「ある方向に」、「ある方向に沿って」、「平行」、「直交」、「中心」、「同心」或いは「同軸」等の相対的或いは絶対的な配置を表す表現は、厳密にそのような配置を表すのみならず、公差、若しくは、同じ機能が得られる程度の角度や距離をもって相対的に変位している状態も表すものとする。
　例えば、「同一」、「等しい」及び「均質」等の物事が等しい状態であることを表す表現は、厳密に等しい状態を表すのみならず、公差、若しくは、同じ機能が得られる程度の差が存在している状態も表すものとする。
　例えば、四角形状や円筒形状等の形状を表す表現は、幾何学的に厳密な意味での四角形状や円筒形状等の形状を表すのみならず、同じ効果が得られる範囲で、凹凸部や面取り部等を含む形状も表すものとする。
　一方、一つの構成要素を「備える」、「具える」、「具備する」、「含む」、又は「有する」という表現は、他の構成要素の存在を除外する排他的な表現ではない。 Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.
For example, the expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" are strict. In addition to representing such an arrangement, it also represents a state in which the components are relatively displaced by a tolerance or an angle or a distance at which the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous" that indicate that they are in the same state are not limited to a state in which they are exactly equal to each other. It also represents the existing state.
For example, the representation of a shape such as a quadrangle or a cylinder does not only represent a shape such as a quadrangle or a cylinder in a geometrically strict sense, but also an uneven portion or a chamfer within a range in which the same effect can be obtained. The shape including parts and the like is also shown.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.
　図１は、一実施形態に係る熱交換器を模式的に示す斜視図である。図１に示す熱交換器１０は、例えば冷凍庫やフリーザなどに設けられるエアクーラである。熱交換器１０のケーシング１２は、被冷却空気ａから流入する前面及び流出する後面は開放されており、例えば、ファン１４（１４ａ、１４ｂ、１４ｃ）などの稼働によってケーシング１２の前面から流入し後面から流出する被冷却空気ａの流路が形成される。この冷却空気流路中に、複数の伝熱管１６が設けられる。伝熱管１６は、冷却空気流路における被冷却空気ａの流れ方向（矢印ａ方向）と直交する幅方向（矢印ｂ方向）（第１方向）に沿って延在する。 FIG. 1 is a perspective view schematically showing a heat exchanger according to one embodiment. The heat exchanger 10 shown in FIG. 1 is an air cooler provided in, for example, a freezer or a freezer. The casing 12 of the heat exchanger 10 has an open front surface that flows in from the cooled air a and a rear surface that flows out. For example, the casing 12 of the heat exchanger 10 flows in from the front surface of the casing 12 by the operation of the fan 14 (14a, 14b, 14c) and the like. A flow path for the air to be cooled a flowing out from is formed. A plurality of heat transfer tubes 16 are provided in this cooling air flow path. The heat transfer tube 16 extends along the width direction (arrow b direction) (first direction) orthogonal to the flow direction (arrow a direction) of the cooled air a in the cooling air flow path.
　また、図２に示すように、複数の伝熱管１６のうちデフロスト対象管として選択された伝熱管１６をデフロストするためのデフロストユニット１８を備えている。複数の伝熱管１６は、被冷却空気ａの流れ方向及び矢印ｂ方向に直交する上下方向（矢印ｃ方向）（第２方向）に沿って配列された複数の伝熱管１６により形成される伝熱管列が、流れ方向に複数並ぶように配列されている。なお、図１において、伝熱管１６は、ケーシング１２内の上部領域のみ図示され、他の領域では伝熱管１６の図示は省略されているが、実際は他の領域のも伝熱管１６が配置され、上部領域と同様に、複数の伝熱管グループが存在する。 Further, as shown in FIG. 2, a defrost unit 18 for defrosting the heat transfer tube 16 selected as the defrosting target tube among the plurality of heat transfer tubes 16 is provided. The plurality of heat transfer tubes 16 are formed by a plurality of heat transfer tubes 16 arranged in a vertical direction (arrow c direction) (second direction) orthogonal to the flow direction of the cooled air a and the arrow b direction. The rows are arranged so that a plurality of rows are arranged in the flow direction. In addition, in FIG. 1, the heat transfer tube 16 is illustrated only in an upper region in the casing 12, and the heat transfer tube 16 is not illustrated in other areas, but in reality, the heat transfer tube 16 is arranged also in other areas, As with the upper region, there are multiple heat transfer tube groups.
　冷却空気流路は、矢印ｃ方向に並ぶ複数の流路領域Ｆａ、Ｆｂ及びＦｃを含む。複数の伝熱管１６は、複数の流路領域Ｆａ～Ｆｃに夫々対応し、かつ同一の流路領域内において流れ方向にて互いに隣接する２以上の伝熱管列に属する複数の伝熱管１６により形成される複数の伝熱管グループＴａ、Ｔｂ、Ｔｃ、・・・を含む。デフロストユニット１８は、複数の伝熱管グループのうち１つ以上の伝熱管グループの伝熱管１６をデフロスト対象管として選択的にデフロストを行うように構成される。 The cooling air flow passage includes a plurality of flow passage regions Fa, Fb and Fc arranged in the direction of arrow c. The plurality of heat transfer tubes 16 are formed by the plurality of heat transfer tubes 16 respectively corresponding to the plurality of flow path areas Fa to Fc and belonging to two or more heat transfer tube rows adjacent to each other in the same flow path area in the flow direction. A plurality of heat transfer tube groups Ta, Tb, Tc, ... The defrost unit 18 is configured to selectively defrost the heat transfer tubes 16 of one or more heat transfer tube groups among the plurality of heat transfer tube groups as defrosting target tubes.
　デフロストユニット１８によって、上記伝熱管グループＴａ、Ｔｂ、Ｔｃ、・・・のうち１つ以上の伝熱管グループをデフロスト対象管として選択的にデフロストを行う。伝熱管グループ毎に霜の付着及び成長の度合いは異なるため、成長した霜層によって気体流路が閉塞される時間は、伝熱管グループ毎に異なる。そこで、各伝熱管グループをデフロストする順序を適宜選択することで、各伝熱管グループの伝熱面における空気流路の閉塞を防止しながら、デフロスト時加えられる熱による熱交換器１０の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が伝熱面に再付着するのを抑制できる。さらには、熱交換器の無駄なデフロスト加熱（デフロスト流体が保有する熱によって伝熱管に加えられる加熱）を抑えながら効率的な冷却装置の運転が可能となる。 By the defrost unit 18, one or more heat transfer tube groups among the heat transfer tube groups Ta, Tb, Tc, ... Are selectively defrosted as tubes to be defrosted. Since the degree of adhesion and growth of frost is different for each heat transfer tube group, the time when the gas flow path is blocked by the grown frost layer is different for each heat transfer tube group. Therefore, by appropriately selecting the order of defrosting each heat transfer tube group, the thermal efficiency of the heat exchanger 10 is reduced by the heat applied during defrosting while preventing the air passages from being blocked on the heat transfer surface of each heat transfer tube group. In addition, it is possible to prevent the frost separated from the adhering surface during defrosting from re-adhering to the heat transfer surface. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger (heating added to the heat transfer tubes by the heat of the defrost fluid).
　例えば、伝熱管グループ毎に伝熱面周囲の空気流路の着霜による閉塞時間を求めておき、各伝熱管グループで閉塞時間当たり少なくとも１回のデフロスト運転を行うようにする。これによって、各伝熱管グループの空気流路の閉塞を抑制できる。あるいは、同一流路領域においては、上流側伝熱管グループと下流側伝熱管グループとを同時にデフロスト運転するようにする。これによって、上流側伝熱管で剥離した霜が下流側伝熱管に再付着するのを抑制できる。あるいは、後述するように、着霜の成長が遅い下流側伝熱管グループほどデフロストの時間間隔を長くする。これによって、デフロストによる熱交換器の熱効率の低下を抑制できる。 For example, for each heat transfer tube group, the blocking time due to frost formation on the air flow path around the heat transfer surface is obtained, and each heat transfer tube group performs defrost operation at least once per blocking time. Thereby, the blockage of the air flow path of each heat transfer tube group can be suppressed. Alternatively, in the same flow path region, the upstream heat transfer tube group and the downstream heat transfer tube group are simultaneously defrosted. As a result, it is possible to prevent the frost separated in the upstream heat transfer tube from reattaching to the downstream heat transfer tube. Alternatively, as described later, the defrost time interval is set longer for the downstream heat transfer tube group in which the growth of frost is slower. As a result, it is possible to suppress a decrease in thermal efficiency of the heat exchanger due to defrost.
　図２は、熱交換器１０の冷却運転時に伝熱管１６に冷媒を供給して被冷却空気ａを冷却する冷凍機２０及びデフロスト運転時にデフロスト対象となる伝熱管グループにデフロスト流体を供給するデフロストユニット１８の構成の一実施形態を示す。冷媒回路２２を循環する冷媒は、ガス状で圧縮機２４に吸入され、圧縮機２４で加圧された後、コンデンサ２６で冷却されて液化する。コンデンサ２６で液化された冷媒液は一旦レシーバ２８に貯留された後、膨張弁３０を経て減圧される。膨張弁３０で減圧された冷媒は、熱交換器１０の各伝熱管グループＴａ、Ｔｂ及びＴｃに設けられた逆止弁３２を経て熱交換器１０の伝熱管１６に供給され、被冷却空気ａを所定の冷却温度に冷却する。被冷却空気ａの冷却に供された後の冷媒は冷媒回路２２に戻される。 FIG. 2 is a defrost unit for supplying a refrigerant to the heat transfer tubes 16 to cool the cooled air a during the cooling operation of the heat exchanger 10 and a defrost unit for supplying the defrost fluid to the heat transfer tube group to be defrosted during the defrost operation. 18 shows an embodiment of 18 configurations. The refrigerant circulating in the refrigerant circuit 22 is sucked into the compressor 24 in a gaseous state, pressurized by the compressor 24, cooled by the condenser 26, and liquefied. The refrigerant liquid liquefied by the condenser 26 is once stored in the receiver 28, and then depressurized via the expansion valve 30. The refrigerant decompressed by the expansion valve 30 is supplied to the heat transfer pipe 16 of the heat exchanger 10 through the check valve 32 provided in each heat transfer pipe group Ta, Tb, and Tc of the heat exchanger 10, and the cooled air a Is cooled to a predetermined cooling temperature. The refrigerant that has been used to cool the cooled air a is returned to the refrigerant circuit 22.
　デフロスト対象管となった伝熱管グループには、レシーバ２８内の高圧下の冷媒（ガス相部）がバッファタンク４４に貯留され、デフロスト流路３４を介して供給される。この高圧下の冷媒は温度、圧力等の状態を調整されてバッファタンク４４に貯留される。つまり圧力調整弁３６を経て減圧され、加熱部４６で加熱されることで温度、圧力等の状態を調整される。このデフロスト用冷媒ガスは、デフロスト対象管となった伝熱管グループに送られ、この伝熱管グループでデフロストに供される。冷媒ガスは伝熱管内部で凝縮液化した後、キャピラリチューブ３８を経て膨張減圧され、低圧冷媒ラインに合流する。その後、他の伝熱管グループを経て蒸発ガス化して冷媒回路２２に戻される。なお、このキャピラリチューブ３８は電磁弁や膨張弁でもよい。
　一実施形態では、冷媒回路２２及びデフロスト流路３４には、開閉用の電磁弁４７及び４９が設けられている。 The high-pressure refrigerant (gas phase portion) in the receiver 28 is stored in the buffer tank 44 in the heat transfer tube group that has become the defrost target tube, and is supplied through the defrost flow path 34. The refrigerant under high pressure is stored in the buffer tank 44 after adjusting the temperature, pressure, and other conditions. That is, the pressure is adjusted through the pressure adjusting valve 36, and the temperature is reduced by the heating unit 46 so that the temperature, pressure, and other conditions are adjusted. This defrosting refrigerant gas is sent to the heat transfer tube group that is the defrosting target tube, and is provided for defrosting in this heat transfer tube group. After the refrigerant gas is condensed and liquefied inside the heat transfer tube, it is expanded and decompressed through the capillary tube 38 and joins the low pressure refrigerant line. After that, it is vaporized and gasified through another heat transfer tube group and is returned to the refrigerant circuit 22. The capillary tube 38 may be a solenoid valve or an expansion valve.
In one embodiment, the refrigerant circuit 22 and the defrost passage 34 are provided with solenoid valves 47 and 49 for opening and closing.
　一実施形態では、デフロストユニット１８は、複数の伝熱管列のうち流れ方向最上流側の伝熱管列（この実施形態では伝熱管グループＴａに属する伝熱管列）のみをデフロスト対象管として選択的にデフロストするように構成される。最上流側伝熱管列は熱伝達率が高く、かつ被冷却気体に含まれるミスト（液体及び固体）が慣性力により上流側先端部分に衝突するために、霜の堆積、積層が促進される。これによって、最上流側伝熱管列に集中して着霜が生じ、かつ着霜の成長が早くなる。従って、最上流側伝熱管列に集中してデフロスト運転を行うことが有効となる。
　この実施形態によれば、被冷却空気ａの流れ方向最上流側の伝熱管列（伝熱管グループＴａに属する伝熱管列）のみをデフロスト対象管として選択的にデフロストすることで、最上流側伝熱管列を優先してデフロスト頻度を増加できる。そのため、最上流側伝熱管列の着霜の成長を抑制できると共に、逆に下流側伝熱管グループのデフロスト頻度を控えることで省エネを達成できる。 In one embodiment, the defrost unit 18 selectively selects, as a defrost target tube, only the heat transfer tube row on the most upstream side in the flow direction (heat transfer tube row belonging to the heat transfer tube group Ta in this embodiment) among the plurality of heat transfer tube rows. Configured to defrost. The most upstream heat transfer tube array has a high heat transfer coefficient, and the mist (liquid and solid) contained in the gas to be cooled collides with the upstream end portion by the inertial force, so that frost accumulation and stacking are promoted. As a result, frost is concentrated on the uppermost stream side heat transfer tube row, and the growth of frost is accelerated. Therefore, it is effective to concentrate the defrosting operation on the most upstream heat transfer tube row.
According to this embodiment, by selectively defrosting only the heat transfer tube row (heat transfer tube row belonging to the heat transfer tube group Ta) on the most upstream side in the flow direction of the cooled air a as the defrosting target tube, the most upstream heat transfer is performed. The defrost frequency can be increased by giving priority to the row of heat tubes. Therefore, it is possible to suppress the growth of frost on the uppermost stream side heat transfer tube row and conversely save energy by suppressing the defrost frequency of the downstream side heat transfer tube group.
　一実施形態では、図３に示すように、複数の伝熱管１６が貫通又は接触するように冷却空気流路内にて流れ方向（矢印ａ方向）に沿って板状放熱部材４０が設けられる。板状放熱部材４０を設けることで、伝熱面積が増加するため、熱交換器１０の伝熱性能を向上できる。また、板状放熱部材４０は被冷却空気ａの流れ方向に沿って設けられるので、被冷却空気ａの乱れを抑制できる。図４Ａに示すように、被冷却空気ａの乱れが抑制された板状放熱部材４０の表面には、板状放熱部材４０の表面に近づくほど温度が徐々に低くなる温度境界層Ｂｔが形成される。この温度境界層の形成によって被冷却空気ａと板状放熱部材４０との熱伝達率が低下するので、板状放熱部材４０の表面に形成される霜層の成長を抑制できる。図４Ａに温度境界層Ｂｔの温度分布を模式的に示している。 In one embodiment, as shown in FIG. 3, a plate-shaped heat dissipation member 40 is provided along the flow direction (direction of arrow a) in the cooling air flow path so that the plurality of heat transfer tubes 16 penetrate or contact each other. Since the heat transfer area is increased by providing the plate-shaped heat dissipation member 40, the heat transfer performance of the heat exchanger 10 can be improved. Further, since the plate-shaped heat dissipation member 40 is provided along the flow direction of the cooled air a, it is possible to suppress the disturbance of the cooled air a. As shown in FIG. 4A, on the surface of the plate-shaped heat dissipation member 40 in which the turbulence of the cooled air a is suppressed, a temperature boundary layer Bt is formed in which the temperature gradually decreases toward the surface of the plate-shaped heat dissipation member 40. It The formation of this temperature boundary layer lowers the heat transfer coefficient between the cooled air a and the plate-shaped heat dissipation member 40, so that the growth of the frost layer formed on the surface of the plate-shaped heat dissipation member 40 can be suppressed. FIG. 4A schematically shows the temperature distribution of the temperature boundary layer Bt.
　温度境界層Ｂｔは上流側に行くほど薄くなる。そのため、上流側に行くほど被冷却空気ａと伝熱管１６内を流れる冷却媒体との熱伝達が促進される。従って、通常の冷却運転時に板状放熱部材４０の上流側先端部分４０ａに霜付着量が増えることが想定される。逆に、流れ方向下流側ではこの温度境界層Ｂｔの形成によって板状放熱部材４０の表面に形成される霜層の成長を抑制できる。 The temperature boundary layer Bt becomes thinner toward the upstream side. Therefore, the heat transfer between the air to be cooled a and the cooling medium flowing in the heat transfer tube 16 is promoted toward the upstream side. Therefore, it is assumed that the amount of frost attached to the upstream end portion 40a of the plate-shaped heat dissipation member 40 increases during the normal cooling operation. On the other hand, on the downstream side in the flow direction, the growth of the frost layer formed on the surface of the plate-shaped heat dissipation member 40 can be suppressed by the formation of the temperature boundary layer Bt.
　一実施形態では、図３示すように、板状放熱部材４０は、流れ方向に沿って伝熱管グループ毎に互いに温度境界層Ｂｔを乱さないような間隔を置いて複数並列に配置される。複数の板状放熱部材４０が配置されることで、伝熱面積が増加し、伝熱性能を向上できる。また、板状放熱部材４０が被冷却空気ａの流れ方向に沿って配置されているため、被冷却空気ａの乱れを抑制できる。また、複数の板状放熱部材４０は伝熱管グループ毎に互いに温度境界層Ｂｔを乱さないような間隔を置いて配置されているため、隣り合う伝熱管グループ同士の板状放熱部材間の空隙の温度境界層Ｂｔが維持され、その空隙に面する板状放熱部材の流れ方向上流側の端部の霜層の成長を抑制することで、着霜の集中を抑制し、部分閉塞を抑制できる。また、この構成によれば、デフロスト時に隣り合う伝熱管グループの温度差があっても、この空隙が断熱材の役割を果たすため、隣りの伝熱管グループへの影響を抑制し、熱交換効率の低下を抑制できる。
　なお、板状放熱部材４０は、平板形状とすることで、被冷却空気ａの乱れを最大限に抑制できるが、平板状放熱部材に限られず、コルゲート形状、ルーバ形状又はウェーブ形状としてもよい。 In one embodiment, as shown in FIG. 3, the plate-shaped heat dissipation members 40 are arranged in parallel along the flow direction at intervals such that they do not disturb the temperature boundary layer Bt for each heat transfer tube group. By disposing the plurality of plate-shaped heat dissipation members 40, the heat transfer area is increased and the heat transfer performance can be improved. Further, since the plate-shaped heat dissipation member 40 is arranged along the flow direction of the cooled air a, it is possible to suppress the disturbance of the cooled air a. In addition, since the plurality of plate-shaped heat dissipation members 40 are arranged at intervals so as not to disturb the temperature boundary layer Bt for each heat transfer tube group, a gap between the plate-shaped heat dissipation members of adjacent heat transfer tube groups is formed. The temperature boundary layer Bt is maintained, and the growth of the frost layer at the end of the plate-shaped heat dissipation member facing the gap on the upstream side in the flow direction is suppressed, whereby the concentration of frost can be suppressed and partial blockage can be suppressed. Further, according to this configuration, even if there is a temperature difference between the adjacent heat transfer tube groups at the time of defrosting, since this void serves as a heat insulating material, the influence on the adjacent heat transfer tube groups is suppressed, and the heat exchange efficiency is improved. The decrease can be suppressed.
Note that the plate-shaped heat dissipation member 40 can suppress the turbulence of the air to be cooled a maximum by forming the plate-shaped heat dissipation member 40, but the plate-shaped heat dissipation member 40 is not limited to the plate-shaped heat dissipation member, and may have a corrugated shape, a louver shape, or a wave shape.
　一実施形態では、複数の伝熱管１６の配置は、被冷却空気ａの乱流を形成せずに霜層の成長を抑制し，慣性によるミストの付着に起因する着霜の集中を抑制するという観点から、被冷却空気ａの流れに対して千鳥配置とするより格子配置とするのが望ましい。また、伝熱促進の観点からは千鳥配置とするのが望ましく、交換熱量やデフロストサイクル時間の条件等に関連して適宜選択すると良い。 In one embodiment, the arrangement of the plurality of heat transfer tubes 16 suppresses the growth of the frost layer without forming the turbulent flow of the cooled air a, and suppresses the concentration of frost formation due to the attachment of mist due to inertia. From the viewpoint, it is preferable to use the lattice arrangement rather than the staggered arrangement with respect to the flow of the cooled air a. In addition, from the viewpoint of promoting heat transfer, it is desirable to arrange in a staggered manner, and it may be appropriately selected in relation to the conditions such as the heat exchange amount and the defrost cycle time.
　一実施形態では、図３に示すように、板状放熱部材４０は、被冷却空気ａの流れ方向最上流側に設けられた伝熱管１６（１６ａ）から流れ方向で伝熱管１６（１６ａ）に隣接する１個以上の伝熱管１６まで延在する。上述のように、板状放熱部材４０の上流側先端部分４０ａは温度境界層Ｂｔが薄いため着霜の成長が早くなる。そこで板状放熱部材４０を下流側の伝熱管１６まで延在させることで、第２の先端部分を形成させないようにする。こうして温度境界層Ｂｔを下流側まで連続して形成でき、温度境界層Ｂｔを下流側まで途絶えさせないことで、着霜の成長を抑制できる。 In one embodiment, as shown in FIG. 3, the plate-shaped heat dissipation member 40 moves from the heat transfer tube 16 (16a) provided on the most upstream side in the flow direction of the cooled air a to the heat transfer tube 16 (16a) in the flow direction. It extends to one or more adjacent heat transfer tubes 16. As described above, since the temperature boundary layer Bt is thin at the upstream end portion 40a of the plate-shaped heat dissipation member 40, the growth of frost is accelerated. Therefore, the plate-shaped heat dissipation member 40 is extended to the heat transfer tube 16 on the downstream side so that the second tip portion is not formed. In this way, the temperature boundary layer Bt can be continuously formed to the downstream side, and the growth of frost can be suppressed by not interrupting the temperature boundary layer Bt to the downstream side.
　一実施形態では、図４Ａ及び図４Ｂに示すように、板状放熱部材４０は、被冷却空気ａの流れ方向で２個以上の伝熱管グループＴａ及びＴｂに跨るように配置されると共に、これら伝熱管グループ間の領域に伝熱管グループ間の伝熱を抑制する断熱域４２（４２ａ、４２ｂ）を有する。
　この実施形態によれば、板状放熱部材４０の伝熱管グループ間の領域に断熱域４２を有するため、断熱域４２の一方側の伝熱管グループＴａが冷却運転を行い、他方側の伝熱管グループＴｂがデフロスト運転を行うとき、デフロスト時に加えられる熱が冷却運転中の伝熱管グループに伝わって熱交換器１０の冷却効率を低下させるのを抑制できる。 In one embodiment, as shown in FIGS. 4A and 4B, the plate-shaped heat dissipation member 40 is arranged so as to straddle two or more heat transfer tube groups Ta and Tb in the flow direction of the cooled air a, and Insulation regions 42 (42a, 42b) that suppress heat transfer between the heat transfer tube groups are provided in the areas between the heat transfer tube groups.
According to this embodiment, since the heat insulating area 42 is provided in the area between the heat transfer tube groups of the plate-shaped heat dissipation member 40, the heat transfer tube group Ta on one side of the heat insulating area 42 performs the cooling operation and the heat transfer tube group on the other side. When Tb performs the defrosting operation, it is possible to prevent the heat added during the defrosting from being transferred to the heat transfer tube group during the cooling operation and reducing the cooling efficiency of the heat exchanger 10.
　図４Ａに示す実施形態では、断熱域４２（４２ａ）は、被冷却空気ａの流れ方向で温度境界層Ｂｔが途切れずに維持可能な長さに形成された隙間で構成されている。この隙間に存在する空気は断熱性を有するので、該隙間を形成することで、断熱域を形成できる。また、この隙間は被冷却空気ａの流れ方向で温度境界層Ｂｔが途切れずに維持可能な長さに形成されているので、この隙間によって途切れた板状放熱部材４０の端部で着霜が抑制される。
　図４Ｂに示す実施形態では、断熱域４２（４２ｂ）は、熱伝導率が小さい物質で構成された断熱域を構成している。この断熱域の表面は被冷却空気ａが乱れないように平滑に形成される。 In the embodiment shown in FIG. 4A, the heat insulating region 42 (42a) is composed of a gap formed in a length that allows the temperature boundary layer Bt to be maintained without interruption in the flow direction of the cooled air a. Since the air existing in this gap has a heat insulating property, the heat insulating region can be formed by forming the gap. In addition, since this gap is formed to have a length that allows the temperature boundary layer Bt to be maintained without interruption in the flow direction of the cooled air a, frost is formed at the end of the plate-shaped heat dissipation member 40 that is interrupted by this gap. Suppressed.
In the embodiment shown in FIG. 4B, the heat insulating zone 42 (42b) constitutes a heat insulating zone made of a material having a low thermal conductivity. The surface of this adiabatic region is formed smooth so that the air to be cooled a is not disturbed.
　一実施形態では、図２に示すように、デフロストユニット１８は、伝熱管グループ毎に伝熱管１６に霜の付着面温度を０℃未満でかつ被冷却空気ａの温度より高い温度に維持可能なデフロスト流体を供給可能なデフロスト流体供給部５０を備える。特許文献１に記載されているように、デフロスト時に霜の付着面温度を０℃未満でかつ被冷却空気ａの温度より高い温度に維持することで、付着面に付着した霜層を昇華させ、飛散させることができる。例えば、霜の付着面温度を－２℃～－５℃に維持する。
　この実施形態によれば、デフロスト流体供給部５０によって、デフロスト運転を行う伝熱管グループに対して、霜の付着面温度を上記温度範囲に維持可能なデフロスト流体を供給することで、伝熱面に付着した霜を昇華させて除去する昇華デフロストが可能になる。 In one embodiment, as shown in FIG. 2, the defrost unit 18 can maintain the surface temperature of frost on the heat transfer tubes 16 for each heat transfer tube group at a temperature of less than 0 ° C. and higher than the temperature of the cooled air a. The defrost fluid supply part 50 which can supply a defrost fluid is provided. As described in Patent Document 1, by maintaining the adhesion surface temperature of frost at a temperature lower than 0 ° C. and higher than the temperature of the cooled air a during defrosting, the frost layer adhered to the adhesion surface is sublimated, Can be scattered. For example, the temperature of the surface on which frost adheres is maintained at -2 ° C to -5 ° C.
According to this embodiment, the defrost fluid supply unit 50 supplies the defrost fluid capable of maintaining the frost adhering surface temperature within the above temperature range to the heat transfer tube group performing the defrost operation, so that the heat transfer surface Sublimation defrost that sublimes and removes the adhered frost becomes possible.
　一実施形態では、デフロスト流体供給部５０は、デフロスト流路３４に設けられたバッファタンク４４を含む。バッファタンク４４にはバッファタンク４４に貯留されたデフロスト流体を加熱するための加熱部４６を備え、制御部４８は、圧力調整弁３６の開度を制御すると共に、加熱部４６を制御することで、デフロスト運転時に伝熱管グループに供給される冷却媒体の温度、圧力等の状態が、霜の付着面温度を０℃未満でかつ被冷却空気ａの温度より高い温度に維持可能な状態に制御する。 In one embodiment, the defrost fluid supply unit 50 includes a buffer tank 44 provided in the defrost flow passage 34. The buffer tank 44 includes a heating unit 46 for heating the defrost fluid stored in the buffer tank 44, and the control unit 48 controls the opening degree of the pressure adjusting valve 36 and controls the heating unit 46. , The state of the temperature, pressure, etc. of the cooling medium supplied to the heat transfer tube group during the defrost operation is controlled to a state in which the frost adhesion surface temperature can be maintained below 0 ° C. and higher than the temperature of the cooled air a. ..
　一実施形態では、図１に示すように、複数の伝熱管グループを被冷却空気ａの流れ方向に配置するようにしてもよい。例えば、被冷却空気ａの流れ方向で２つの伝熱管グループを配置してもよい。また、複数の伝熱管グループを上下方向に重ねて配置するようにしてもよい。
　また、図５Ａに示すように、複数の伝熱管グループＴａ、Ｔｂ及びＴｃをファン１４を中心としてファン１４を囲むように円弧状に形成してもよい。複数の伝熱管グループＴａ、Ｔｂ及びＴｃはこの順序で被冷却空気ａの上流側から配置する。図５Ｂに示す実施形態は、伝熱管群を複数の流路領域Ｆａ、Ｆｂ及びＦｃに分け、各流路領域が複数の伝熱管グループＴａ、Ｔｂ及びＴｃで構成される例である。さらには、ファン１４を複数の伝熱管グループの上流側に配置し、押込み型のファンとして稼働させてもよい。 In one embodiment, as shown in FIG. 1, a plurality of heat transfer tube groups may be arranged in the flow direction of the cooled air a. For example, two heat transfer tube groups may be arranged in the flow direction of the cooled air a. In addition, a plurality of heat transfer tube groups may be arranged so as to be vertically stacked.
Further, as shown in FIG. 5A, a plurality of heat transfer tube groups Ta, Tb, and Tc may be formed in an arc shape so as to surround the fan 14 with the fan 14 as the center. The plurality of heat transfer tube groups Ta, Tb, and Tc are arranged in this order from the upstream side of the cooled air a. The embodiment shown in FIG. 5B is an example in which the heat transfer tube group is divided into a plurality of flow path areas Fa, Fb, and Fc, and each flow path area is configured by a plurality of heat transfer tube groups Ta, Tb, and Tc. Further, the fan 14 may be arranged upstream of the plurality of heat transfer tube groups and operated as a push-in type fan.
　一実施形態に係る熱交換器のデフロスト方法は、図１に示す熱交換器１０を用いたデフロスト方法に係る。即ち、熱交換器１０は、被冷却空気ａが流れる冷却空気流路と、この冷却空気流路内において、該冷却空気流路における被冷却空気ａの流れ方向と直交する方向（矢印ｂ方向／第１方向）に沿って延在する複数の伝熱管１６と、複数の伝熱管１６のうちデフロスト対象管をデフロストするためのデフロストユニット１８と、を備える。複数の伝熱管１６は、被冷却空気ａの流れ方向（矢印ａ方向）及びおよび矢印ｂ方向に直交する方向（矢印ｃ方向／第２方向）に沿って配列された複数の伝熱管１６により形成される伝熱管列が、被冷却空気ａの流れ方向に複数並ぶように配列される。冷却空気流路は、矢印ｃ方向に並ぶ複数の流路領域Ｆａ、Ｆｂ及びＦｃを含み、複数の伝熱管１６は、これら複数の流路領域に夫々対応し、かつ、同一の流路領域内において被冷却空気ａの流れ方向にて互いに隣接する２以上の伝熱管列に属する複数の伝熱管１６により形成される複数の伝熱管グループＴａ、Ｔｂ及びＴｃを含む。 The defrosting method of the heat exchanger according to the embodiment relates to the defrosting method using the heat exchanger 10 shown in FIG. That is, the heat exchanger 10 includes a cooling air passage through which the cooled air a flows, and a direction (arrow b direction / arrow b direction / A plurality of heat transfer tubes 16 extending along the first direction) and a defrost unit 18 for defrosting a defrost target tube among the plurality of heat transfer tubes 16 are provided. The plurality of heat transfer tubes 16 are formed by the plurality of heat transfer tubes 16 arranged along a direction (arrow a direction) of the cooled air a and a direction (arrow c direction / second direction) orthogonal to the arrow b direction. A plurality of rows of heat transfer tubes are arranged so as to be aligned in the flow direction of the cooled air a. The cooling air flow path includes a plurality of flow path areas Fa, Fb, and Fc arranged in the direction of arrow c, and the plurality of heat transfer tubes 16 respectively correspond to the plurality of flow path areas and within the same flow path area. In, a plurality of heat transfer tube groups Ta, Tb and Tc formed by a plurality of heat transfer tubes 16 belonging to two or more heat transfer tube rows adjacent to each other in the flow direction of the cooled air a are included.
　図６に示すように、このデフロスト方法は、複数の伝熱管グループＴａ、Ｔｂ及びＴｃのうち１つ以上の伝熱管グループをデフロスト対象管として選択し、該１つ以上の伝熱管グループ毎に順々に繰り返しデフロストする（デフロストステップＳ１０）を備える。
　上記方法によれば、複数の伝熱管グループＴａ、Ｔｂ、Ｔｃ・・・のうち１つ以上の伝熱管グループ毎に順々に繰り返しデフロストすることで、各伝熱管１６の伝熱面における被冷却空気ａの閉塞を防止しながら、デフロスト運転による熱交換器１０の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が下流側の伝熱面に再付着するのを抑制できる。さらには、熱交換器の無駄なデフロスト加熱を抑えながら効率的な冷却装置の運転が可能となる。 As shown in FIG. 6, in this defrosting method, one or more heat transfer tube groups among a plurality of heat transfer tube groups Ta, Tb, and Tc are selected as defrosting target tubes, and the one or more heat transfer tube groups are sequentially selected. Each step is repeatedly defrosted (defrosting step S10).
According to the above method, the heat transfer surfaces of the heat transfer tubes 16 are cooled by repeatedly defrosting one or more heat transfer tube groups among the plurality of heat transfer tube groups Ta, Tb, Tc, ... While preventing the blockage of the air a, it is possible to suppress a decrease in the thermal efficiency of the heat exchanger 10 due to the defrosting operation, and it is possible to suppress the re-adhesion of the frost separated from the adhering surface during the defrosting to the downstream heat transfer surface. Further, it is possible to efficiently operate the cooling device while suppressing wasteful defrost heating of the heat exchanger.
　一実施形態では、図２に示すように、デフロストユニット１８は、複数の伝熱管列のうち流れ方向最上流側の伝熱管列（この実施形態では伝熱管グループＴａに属する伝熱管列）のみをデフロスト対象管として選択的にデフロストするように構成され、デフロストステップＳ１０は、被冷却空気ａの流れ方向最上流側の伝熱管列（伝熱管グループＴａに属する伝熱管列）のみをデフロスト対象管として選択的にデフロストする（ステップＳ１０ａ）。
　このように、被冷却空気ａの流れ方向最上流側伝熱管列のみをデフロスト対象管として選択的にデフロストすることで、最上流側伝熱管列の着霜の成長を抑制できる。 In one embodiment, as shown in FIG. 2, the defrost unit 18 includes only the heat transfer tube row on the most upstream side in the flow direction among the plurality of heat transfer tube rows (in this embodiment, the heat transfer tube rows belonging to the heat transfer tube group Ta). The defrosting step S10 is configured to selectively defrost as the defrosting target tube. In the defrosting step S10, only the heat transfer tube row on the most upstream side in the flow direction of the cooled air a (heat transfer tube row belonging to the heat transfer tube group Ta) is set as the defrosting target tube. Defrost selectively (step S10a).
As described above, by selectively defrosting only the most upstream heat transfer tube row in the flow direction of the cooled air a as the defrosting target tube, it is possible to suppress the growth of frost formation on the most upstream heat transfer tube array.
　一実施形態では、デフロストステップＳ１０において、伝熱管１６の少なくとも一部に付着する着霜量が許容値の上限に達する限界時間に合わせて、すべての伝熱管グループを１回デフロストするに要する１デフロスト時間を設定し、この１デフロスト時間から伝熱管グループの各々のデフロスト実施時間間隔を設定する。
　この実施形態によれば、上記限界時間を被冷却空気ａの流れが板状放熱部材４０間などの隙間を閉塞しない上限値に設定することで、各伝熱管グループにおいて板状放熱部材４０間の被冷却空気ａの流路の閉塞が生じないようにデフロスト運転を実施できる。 In one embodiment, in the defrosting step S10, one defrost required for defrosting all the heat transfer tube groups once according to the limit time when the amount of frost adhering to at least a part of the heat transfer tubes 16 reaches the upper limit of the allowable value. The time is set, and the defrost execution time interval of each heat transfer tube group is set from this one defrost time.
According to this embodiment, the limit time is set to the upper limit value at which the flow of the cooled air a does not close the gaps between the plate-shaped heat radiating members 40, so that between the plate-shaped heat radiating members 40 in each heat transfer tube group. The defrost operation can be performed so that the passage of the cooled air a is not blocked.
　一実施形態では、複数の伝熱管グループの各々のデフロスト実施時間間隔は、流れ方向下流側に配置された伝熱管グループほど長く設定される。被冷却空気ａの流れ方向下流側の伝熱管グループほど着霜の成長は遅くなる傾向にある。
　この実施形態によれば、デフロスト実施時間間隔を被冷却空気ａの流れ方向下流側の伝熱管グループほど長く設定することで、デフロスト運転の頻度を少なくでき、これによって、デフロスト運転実施中の熱交換器１０の冷却効率の低下を抑制できる。 In one embodiment, the defrost execution time interval of each of the plurality of heat transfer tube groups is set longer for the heat transfer tube group arranged on the downstream side in the flow direction. The growth of frost tends to be slower in the heat transfer tube group on the downstream side in the flow direction of the cooled air a.
According to this embodiment, the defrost operation time interval is set to be longer in the heat transfer tube group on the downstream side in the flow direction of the cooled air a, so that the frequency of defrost operation can be reduced, whereby heat exchange during defrost operation is performed. It is possible to suppress a decrease in cooling efficiency of the container 10.
　一実施形態では、デフロストステップＳ１０において、霜の付着面温度を０℃未満でかつ前記被冷却気体の温度より高い温度に維持可能なデフロスト流体をデフロスト対象となった伝熱管グループの伝熱管１６に供給し、該デフロスト流体の保有熱によって伝熱管１６に付着した霜を昇華させる（昇華デフロストステップＳ１０ｂ）。上記デフロスト流体は、例えば、冷凍機２０の圧縮機吐出側の高温の冷媒ガスを用いる。
　この実施形態によれば、デフロスト運転を行う伝熱管１６に対して、霜の付着面温度を０℃未満でかつ被冷却気体の温度より高い温度に維持可能なデフロスト流体を供給することで、付着面に付着した霜を昇華させて除去する昇華デフロストが可能になる。 In one embodiment, in the defrosting step S10, the defrosting fluid that can maintain the frost attachment surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled is transferred to the heat transfer tubes 16 of the heat transfer tube group that is the defrosting target. The frost adhered to the heat transfer tube 16 is sublimated by the retained heat of the defrost fluid (sublimation defrost step S10b). As the defrost fluid, for example, a high-temperature refrigerant gas on the compressor discharge side of the refrigerator 20 is used.
According to this embodiment, by supplying the defrost fluid capable of maintaining the frost attachment surface temperature below 0 ° C. and higher than the temperature of the gas to be cooled to the heat transfer tube 16 performing the defrost operation, Sublimation defrost that sublimes and removes frost adhering to the surface becomes possible.
　一実施形態では、デフロストステップＳ１０において、複数の伝熱管グループの各々において、被冷却空気ａの流れ方向下流側に配置された伝熱管グループほど被冷却空気ａとデフロスト流体との温度差は小さく設定される。被冷却気体とデフロスト流体との温度差が小さいほど、着霜の除去効果は減少するが、後流側ほど霜層の成長が遅い。従って、着霜の成長が遅い流れ方向下流側ほど上記温度差を小さくすることで、着霜除去効果を維持しながら、熱交換器１０の冷却効率の低下を抑制できる。 In one embodiment, in the defrost step S10, in each of the plurality of heat transfer tube groups, the temperature difference between the air to be cooled a and the defrost fluid is set to be smaller as the heat transfer tube group is arranged on the downstream side in the flow direction of the air to be cooled a. To be done. The smaller the temperature difference between the cooled gas and the defrost fluid, the less the frost removal effect, but the slower the frost layer grows toward the wake side. Therefore, the cooling efficiency of the heat exchanger 10 can be suppressed from decreasing while maintaining the frost removal effect by making the temperature difference smaller toward the downstream side in the flow direction where the growth of frost is slow.
　一実施形態では、デフロストステップＳ１０において、デフロスト対象となる伝熱管グループが被冷却空気ａの流れ方向上流側に配置されているとき、ファン１４を逆回転させ、流れ方向を逆向きにする（逆流ステップＳ１０ｃ）。なお、図１に示すように、流路領域Ｆａ、Ｆｂ及びＦｃ毎にファン１４（１４ａ、１４ｂ、１４ｃ）を設けることで、デフロスト対象となる伝熱管グループのみ被冷却空気ａの流れを逆流できる。
　この実施形態によれば、デフロスト運転時に被冷却空気ａの流れ方向を逆向きにすることで、付着面から剥離した霜が下流側の伝熱管１６に再付着するのを抑制できると共に、上流側で処理することを可能とする。また、先端部分に付着した霜を効率的に除去できる。さらに、デフロスト熱源によって昇温した被冷却空気ａが、一度上流側に戻り混合され、他の伝熱管グループに流入するため，熱交換器１０の下流側の温度むらを抑制できる。 In one embodiment, in the defrost step S10, when the heat transfer tube group to be defrosted is arranged on the upstream side in the flow direction of the cooled air a, the fan 14 is rotated in the reverse direction to reverse the flow direction (backflow). Step S10c). As shown in FIG. 1, by providing the fan 14 (14a, 14b, 14c) for each of the flow passage regions Fa, Fb, and Fc, the flow of the cooled air a can be reversed only in the heat transfer tube group to be defrosted. .
According to this embodiment, by reversing the flow direction of the cooled air a during the defrost operation, it is possible to suppress the re-adhesion of the frost separated from the adhering surface to the heat transfer tube 16 on the downstream side, and also to the upstream side. It is possible to process with. Further, the frost attached to the tip portion can be efficiently removed. Furthermore, the cooled air a heated by the defrost heat source once returns to the upstream side, is mixed, and flows into another heat transfer tube group, so that temperature unevenness on the downstream side of the heat exchanger 10 can be suppressed.
　幾つかの実施形態によれば、冷凍庫やフリーザ等に設けられたエアクーラなどの熱交換器において、伝熱面における被冷却気体の閉塞を防止しながら、デフロスト運転による熱交換器の熱効率の低下を抑制し、かつデフロスト時に付着面から剥離した霜が伝熱面に再付着するのを抑制可能である。さらには、熱交換器の無駄なデフロスト加熱を抑えながら効率的な冷却装置の運転が可能なデフロスト手段を実現できる。 According to some embodiments, in a heat exchanger such as an air cooler provided in a freezer, a freezer, or the like, the thermal efficiency of the heat exchanger due to the defrost operation is reduced while preventing the cooled gas from being blocked on the heat transfer surface. It is possible to suppress and prevent the frost separated from the adhesion surface during defrosting from re-adhering to the heat transfer surface. Further, it is possible to realize a defrosting device capable of efficiently operating the cooling device while suppressing wasteful defrosting heating of the heat exchanger.
　１０　　熱交換器
　１２　　ケーシング
　１４（１４ａ、１４ｂ、１４ｃ）　　ファン
　１６　　伝熱管
　１８　　デフロストユニット
　２０　　冷凍機
　２２　　冷媒回路
　２４　　圧縮機
　２６　　コンデンサ
　２８　　レシーバ
　３０　　膨張弁
　３２　　逆止弁
　３４　　デフロスト流路
　３６　　圧力調整弁
　３８　　キャピラリチューブ
　４０　　板状放熱部材
　　４０ａ　　先端部分
　４２（４２ａ、４２ｂ）　　断熱域
　４４　　バッファタンク
　４６　　加熱部
　４７、４９　　電磁弁
　４８　　制御部
　５０　　デフロスト流体供給部
　Ｂｔ　　温度境界層　
　Ｆａ、Ｆｂ、Ｆｃ　　流路領域
　Ｔａ、Ｔｂ、Ｔｃ　　伝熱管グループ
　ａ　　　被冷却空気 10 Heat Exchanger 12 Casing 14 (14a, 14b, 14c) Fan 16 Heat Transfer Tube 18 Defrost Unit 20 Refrigerator 22 Refrigerant Circuit 24 Compressor 26 Condenser 28 Receiver 30 Expansion Valve 32 Check Valve 34 Defrost Flow Path 36 Pressure Control Valve 38 Capillary tube 40 Plate-shaped heat radiating member 40a Tip portion 42 (42a, 42b) Adiabatic area 44 Buffer tank 46 Heating part 47, 49 Solenoid valve 48 Control part 50 Defrost fluid supply part Bt Temperature boundary layer
Fa, Fb, Fc Flow path area Ta, Tb, Tc Heat transfer tube group a Cooled air

Claims (14)

  1. 　被冷却気体が流れる気体流路と、
    　前記気体流路内において、前記気体流路における前記被冷却気体の流れ方向と直交する第１方向に沿って延在する複数の伝熱管と、
    　前記複数の伝熱管のうちデフロスト対象管をデフロストするためのデフロストユニットと、
    を備え、
    　前記複数の伝熱管は、前記流れ方向および前記第１方向に直交する第２方向に沿って配列された複数の前記伝熱管により形成される伝熱管列が、前記流れ方向に複数並ぶように配列され、
    　前記気体流路は、前記第２方向に並ぶ複数の流路領域を含み、
    　前記複数の伝熱管は、前記複数の流路領域に夫々対応し、かつ、同一の前記流路領域内において前記流れ方向にて互いに隣接する２以上の前記伝熱管列に属する複数の前記伝熱管により形成される複数の伝熱管グループを含み、
    　前記デフロストユニットは、前記複数の伝熱管グループのうち１以上の前記伝熱管グループの前記伝熱管を前記デフロスト対象管として選択的にデフロストを行うように構成されたことを特徴とする熱交換器。     A gas flow path through which the cooled gas flows,
    In the gas flow path, a plurality of heat transfer tubes extending along a first direction orthogonal to the flow direction of the gas to be cooled in the gas flow path,
    A defrost unit for defrosting the defrost target pipe among the plurality of heat transfer tubes,
    Equipped with
    The plurality of heat transfer tubes are arranged such that a plurality of heat transfer tube rows formed by the plurality of heat transfer tubes arranged along a second direction orthogonal to the flow direction and the first direction are arranged in the flow direction. Was
    The gas flow path includes a plurality of flow path regions arranged in the second direction,
    The plurality of heat transfer tubes respectively correspond to the plurality of flow path areas and belong to two or more heat transfer tube rows adjacent to each other in the same flow path area in the flow direction. Including a plurality of heat transfer tube groups formed by
    The heat exchanger, wherein the defrost unit is configured to selectively defrost the heat transfer tubes of one or more heat transfer tube groups of the plurality of heat transfer tube groups as the defrosting target tubes.
  2. 　前記デフロストユニットは、複数の前記伝熱管列のうち前記流れ方向最上流側の前記伝熱管列のみを前記デフロスト対象管として選択的にデフロストするように構成されることを特徴とする請求項１に記載の熱交換器。 The defrost unit is configured to selectively defrost only the heat transfer tube row on the most upstream side in the flow direction of the plurality of heat transfer tube rows as the defrosting target tube. The heat exchanger described.
  3. 　前記複数の伝熱管が貫通又は接触するように前記気体流路内にて前記流れ方向に沿って設けられる板状放熱部材を備えることを特徴とする請求項１又は２に記載の熱交換器。 The heat exchanger according to claim 1 or 2, further comprising a plate-shaped heat dissipation member provided along the flow direction in the gas flow path so that the plurality of heat transfer tubes penetrate or contact each other.
  4. 　前記板状放熱部材は、前記流れ方向に沿って前記伝熱管グループ毎に互いに温度境界層を乱さない間隔を置いて複数並列に配置されたことを特徴とする請求項３に記載の熱交換器。 The heat exchanger according to claim 3, wherein a plurality of the plate-shaped heat radiating members are arranged in parallel along the flow direction at intervals that do not disturb a temperature boundary layer for each of the heat transfer tube groups. ..
  5. 　前記板状放熱部材は、前記流れ方向最上流側に設けられた前記伝熱管から前記流れ方向で前記伝熱管に隣接する１個以上の前記伝熱管まで延在することを特徴とする請求項３又は４に記載の熱交換器。 The plate-shaped heat dissipation member extends from the heat transfer tube provided on the most upstream side in the flow direction to one or more heat transfer tubes adjacent to the heat transfer tube in the flow direction. Or the heat exchanger according to 4.
  6. 　前記板状放熱部材は、前記流れ方向で２個以上の前記伝熱管グループに跨るように配置されると共に、前記伝熱管グループ間の領域に前記伝熱管グループ間の伝熱を抑制する断熱域を有することを特徴とする請求項３乃至５の何れか一項に記載の熱交換器。 The plate-shaped heat dissipating member is disposed so as to straddle two or more heat transfer tube groups in the flow direction, and has a heat insulating region in a region between the heat transfer tube groups that suppresses heat transfer between the heat transfer tube groups. It has, The heat exchanger as described in any one of Claim 3 thru | or 5 characterized by the above-mentioned.
  7. 　前記デフロストユニットは、前記伝熱管グループ毎に前記伝熱管に霜の付着面温度を０℃未満でかつ前記被冷却気体の温度より高い温度に維持可能なデフロスト流体を供給可能な一つ又は複数のデフロスト流体供給部を含むことを特徴とする請求項１乃至６の何れか一項に記載の熱交換器。 The defrost unit may supply, for each heat transfer tube group, one or more defrost fluids capable of maintaining the frost adhesion surface temperature of the heat transfer tubes below 0 ° C. and higher than the temperature of the gas to be cooled. The heat exchanger according to claim 1, further comprising a defrost fluid supply unit.
  8. 　被冷却気体が流れる気体流路と、前記気体流路内において、前記気体流路における前記被冷却気体の流れ方向と直交する第１方向に沿って延在する複数の伝熱管と、前記複数の伝熱管のうちデフロスト対象管をデフロストするためのデフロストユニットと、を備え、前記複数の伝熱管は、前記流れ方向および前記第１方向に直交する第２方向に沿って配列された複数の前記伝熱管により形成される伝熱管列が、前記被冷却気体の前記流れ方向に複数並ぶように配列され、前記気体流路は、前記第２方向に並ぶ複数の流路領域を含み、前記複数の伝熱管は、前記複数の流路領域に夫々対応し、かつ、同一の前記流路領域内において前記流れ方向にて互いに隣接する２以上の前記伝熱管列に属する複数の前記伝熱管により形成される複数の伝熱管グループを含む熱交換器のデフロスト方法であって、
    　前記複数の伝熱管グループのうち１以上の前記伝熱管グループをデフロスト対象管として選択し、該１以上の伝熱管グループ毎に順々に繰り返しデフロストするデフロストステップを備えることを特徴とする熱交換器のデフロスト方法。     A gas flow path through which the gas to be cooled flows, a plurality of heat transfer tubes extending in the gas flow path along a first direction orthogonal to the flow direction of the gas to be cooled in the gas flow path, and the plurality of heat transfer tubes A defrost unit for defrosting a defrost target tube among the heat transfer tubes, wherein the plurality of heat transfer tubes are arranged along a second direction orthogonal to the flow direction and the first direction. A row of heat transfer tubes formed by heat tubes is arranged so as to be lined up in the flow direction of the cooled gas, and the gas flow path includes a plurality of flow path areas lined up in the second direction. The heat pipes are formed by the plurality of heat transfer tubes that respectively correspond to the plurality of flow path regions and that belong to two or more heat transfer tube rows that are adjacent to each other in the flow direction in the same flow path region. A defrosting method for a heat exchanger including a plurality of heat transfer tube groups, comprising:
    A heat exchanger characterized by comprising a defrost step of selecting one or more of the heat transfer tube groups from among the plurality of heat transfer tube groups as a defrosting target tube and sequentially defrosting each of the one or more heat transfer tube groups in sequence. Defrost method.
  9. 　前記デフロストユニットは、複数の前記伝熱管列のうち前記流れ方向最上流側の前記伝熱管列のみを前記デフロスト対象管として選択的にデフロストするように構成され、
    　前記デフロストステップは、前記流れ方向最上流側の前記伝熱管列のみを前記デフロスト対象管として選択的にデフロストするステップを含むことを特徴とする請求項８に記載の熱交換器のデフロスト方法。     The defrost unit is configured to selectively defrost only the heat transfer tube row on the most upstream side in the flow direction among the plurality of heat transfer tube rows as the defrosting target tube,
    9. The defrosting method for a heat exchanger according to claim 8, wherein the defrosting step includes a step of selectively defrosting only the heat transfer tube row on the most upstream side in the flow direction as the defrosting target tube.
  10. 　前記デフロストステップにおいて、
    　前記伝熱管の少なくとも一部に付着する着霜量が許容値の上限に達する限界時間に合わせて、すべての前記伝熱管グループを１回デフロストするに要する１デフロスト時間を設定し、該１デフロスト時間から前記伝熱管グループの各々のデフロスト実施時間間隔を設定することを特徴とする請求項８又は９に記載の熱交換器のデフロスト方法。     In the defrosting step,
    The 1 defrost time required to defrost all the heat transfer tube groups once is set in accordance with the limit time when the amount of frost adhering to at least a part of the heat transfer tubes reaches the upper limit of the allowable value, and the 1 defrost time is set. The defrosting method of the heat exchanger according to claim 8 or 9, wherein the defrosting execution time interval of each of the heat transfer tube groups is set.
  11. 　前記複数の伝熱管グループの各々の前記デフロスト実施時間間隔は、前記流れ方向下流側に配置された前記伝熱管グループほど長く設定されることを特徴とする請求項１０に記載の熱交換器のデフロスト方法。 The defrosting time of the heat exchanger according to claim 10, wherein the defrosting execution time interval of each of the plurality of heat transfer tube groups is set longer as the heat transfer tube group arranged on the downstream side in the flow direction. Method.
  12. 　前記デフロストステップにおいて、
    　霜の付着面温度を０℃未満でかつ前記被冷却気体の温度より高い温度に維持可能なデフロスト流体を前記伝熱管に供給し、該デフロスト流体の保有熱によって前記伝熱管に付着した霜を昇華させることを特徴とする請求項８乃至１１の何れか一項に記載の熱交換器のデフロスト方法。     In the defrosting step,
    A defrost fluid capable of maintaining the surface temperature of the frost below 0 ° C. and higher than the temperature of the gas to be cooled is supplied to the heat transfer tube, and the frost attached to the heat transfer tube is sublimated by the heat of the defrost fluid. The defrosting method for a heat exchanger according to any one of claims 8 to 11, wherein the defrosting method is performed.
  13. 　前記デフロストステップにおいて、
    　前記複数の伝熱管グループの各々において、前記流れ方向下流側に配置された前記伝熱管グループほど前記被冷却気体と前記デフロスト流体との温度差は小さく設定されることを特徴とする請求項１２に記載の熱交換器のデフロスト方法。     In the defrosting step,
    In each of the plurality of heat transfer tube groups, a temperature difference between the cooled gas and the defrost fluid is set to be smaller as the heat transfer tube group is arranged on the downstream side in the flow direction. Method for defrosting a heat exchanger as described.
  14. 　前記デフロストステップにおいて、
    　前記流れ方向上流側に配置された前記伝熱管グループがデフロスト対象となったとき、前記流れ方向を逆向きにすることを特徴とする請求項８乃至１３の何れか一項に記載の熱交換器のデフロスト方法。     In the defrosting step,
    The heat exchanger according to any one of claims 8 to 13, wherein when the heat transfer tube group arranged on the upstream side in the flow direction is a target of defrosting, the flow direction is reversed. Defrost method.
PCT/JP2019/043982 2018-11-13 2019-11-08 Heat exchanger and heat exchanger defrosting method WO2020100766A1 (en)

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