Outside air treatment device and outside air treatment method

Abstract

To provide an outside air treatment device and an outside air treatment method that can lower a blowout temperature of conditioned air to be introduced to an indoor space while securing operational reliability.SOLUTION: An outside air treatment device includes: an evaporator provided in an air conditioning main flow passage and cooling first outside air by heat exchange between the first outside air and a refrigerant; and a reheating unit for performing heat exchange between the first outside air that has passed through the evaporator and second outside air of the outside air that has not passed through the evaporator. A clearance between neighboring first fins in the evaporator is wider than a clearance between neighboring second fins in the reheating unit.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an outside air treatment device and an outside air treatment method. [Background technology]

[0002] For example, outdoor air treatment devices may be used as air conditioners installed in various facilities such as factories and laboratories. Outdoor air treatment devices are installed in the outdoor spaces of various facilities, and supply outdoor air to indoor spaces after dehumidifying and cooling it (see, for example, Patent Document 1 below). Outdoor air treatment devices can maintain the inside of a facility at a desired temperature and humidity while maintaining the inside of the facility in a positive pressure state, and therefore there is an increasing need for such devices in terms of hygiene management based on HACCP (Hazard Analysis and Critical Control Point, a hygiene management method that aims to ensure the safety of food, etc.) and infectious disease countermeasures. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-080886 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional outdoor air treatment devices, there is room for improvement in terms of lowering the blowing temperature of the conditioned air introduced into the indoor space while ensuring operational reliability. Specifically, if the evaporation temperature of the refrigerant in the evaporator is lowered so as to lower the blowing temperature, frost is likely to occur due to moisture condensed on the surface of the evaporator. As a result, the flow of the conditioned air may be obstructed between the fins that constitute the evaporator. In addition, if the flow of the conditioned air is obstructed due to frost on the evaporator, the heat exchange efficiency between the evaporator and the conditioned air decreases. As a result, there is a possibility that the refrigerant will return to the compressor without being vaporized (so-called liquid back).

[0005] The present invention provides an outdoor air treatment device and an outdoor air treatment method that can lower the blowing temperature of conditioned air introduced into an indoor space while ensuring operational reliability. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention employs the following aspects. An outdoor air treatment device according to one embodiment of the present invention comprises an air conditioning flow path through which first outdoor air flows, which is outdoor air taken in from outdoors; a first heat exchanger provided in the air conditioning flow path and configured to cool the first outdoor air by exchanging heat between the first outdoor air and a heat medium; and a second heat exchanger provided in the air conditioning flow path downstream of the first heat exchanger and configured to exchange heat between the first outdoor air that has passed through the first heat exchanger and a second outdoor air that is part of the outdoor air and has not passed through the first heat exchanger, wherein the first heat exchanger comprises a plurality of first fins spaced apart from each other in a first direction intersecting a flow direction of the first outdoor air in the air conditioning flow path, and a first pipe penetrating the plurality of first fins and through which a heat medium flows, and the second heat exchanger comprises a plurality of second fins spaced apart from each other in a second direction intersecting the flow direction, and a second pipe penetrating the plurality of second fins and through which the second outdoor air flows, and the distance between adjacent first fins is wider than the distance between adjacent second fins.

[0007] According to this aspect, in the second heat exchanger, heat exchange is performed between the first outside air that has passed through the first heat exchanger (between the adjacent first fins) and the second outside air that has not passed through the first heat exchanger, thereby increasing the temperature of the first outside air and decreasing the relative humidity of the first outside air. As a result, condensation around the air outlet for the first outside air can be suppressed. Here, in this embodiment, by making the interval between adjacent first fins wider than the interval between adjacent second fins, even if condensation occurs on the surface of the first heat exchanger (first fin or first pipe) when the first outside air passes between adjacent first fins, the water is likely to fall between adjacent first fins. Therefore, it is possible to prevent water from accumulating between adjacent first fins. In addition, even if frost forms on the first fins, it is possible to prevent the water between adjacent first fins from impeding the flow of the first outside air between adjacent first fins. In this case, the flow speed of the first outside air passing between adjacent first fins can be reduced, so that the desired temperature can be achieved even if the approach temperature (the difference between the evaporation temperature and the temperature of the first outside air after heat exchange) is small. As a result, frost formation on the surfaces of the first fins can be more reliably suppressed. In addition, the approach temperature can be reduced, improving the cycle efficiency of the refrigerator. This makes it easier to cool the first outside air to the desired temperature while ensuring operational reliability.

[0008] In the outside air treatment device according to the above aspect, the distance between adjacent first fins is preferably set to be equal to or greater than 4 mm and equal to or less than 7 mm. According to the present aspect, by setting the distance between adjacent first fins to 4 mm or more, even if frost forms on the first fins, it is possible to prevent the flow of first outside air between adjacent first fins from being obstructed. On the other hand, by setting the distance between adjacent first fins to 7 mm or less, it is possible to prevent the first heat exchanger from becoming large.

[0009] In the outside air treatment device according to the above aspect, it is preferable that an outer shape of the first heat exchanger seen from the flow direction is larger than an outer shape of the second heat exchanger seen from the flow direction. According to this aspect, even if the distance between adjacent first fins is increased, it is easy to ensure the number of first fins and the heat exchange efficiency in the first heat exchanger.

[0010] In the outside air treatment device according to the above aspect, the heat medium is preferably an HFO refrigerant. According to this embodiment, it is possible to reduce the global warming potential (GWP) and suppress global warming.

[0011] In the above aspect, it is preferable that an evaporation temperature of the HFO refrigerant in the first heat exchanger is set to be equal to or higher than -1°C and equal to or lower than 9°C. According to this aspect, by setting the evaporation temperature of the HFO refrigerant to -1°C or higher, it is possible to suppress frost formation on the surfaces of the first fins. On the other hand, by setting the evaporation temperature of the HFO refrigerant to 9°C or lower, the blowing temperature of the first outside air can be lowered.

[0012] In the outdoor air treatment device according to the above aspect, it is preferable that the device comprises an air conditioning unit having an air conditioning case in which the air conditioning flow path is formed and the first heat exchanger and the second heat exchanger housed in the air conditioning case, a refrigeration unit having a compressor that compresses a heat medium and a condenser that dissipates heat from the heat medium compressed by the compressor and arranged away from the air conditioning unit, and an expansion device arranged between the air conditioning unit and the refrigeration unit and connecting the condenser and the first heat exchanger. According to this aspect, by making the air conditioning unit and the refrigeration unit into separate cases, each unit can be preassembled in the factory. Therefore, at the site, each unit is installed and then the installation of the outside air treatment device is completed by assembling the piping and the like. This makes it possible to improve the ease of transportation and reduce the labor required for installation work. Furthermore, by making the air conditioning unit and the refrigeration unit into separate cases, it is possible to improve maintainability.

[0013] In the outside air treatment device according to the above aspect, it is preferable that a sensor for detecting leakage of the heat medium is provided in a portion of the air conditioning flow path that is located downstream of the second heat exchanger. According to this aspect, even when a slightly flammable heat medium such as an HFO refrigerant is used, leakage of the heat medium can be detected and appropriate measures such as stopping or treating the heat medium can be taken, thereby suppressing leakage of the heat medium and ensuring safety.

[0014] An outside air processing method according to one embodiment of the present invention is an outside air processing method using an outside air processing device that includes an air conditioning flow path through which first outside air flows, the first outside air being taken in from outdoors, a first heat exchanger that is provided in the air conditioning flow path and cools the first outside air by performing heat exchange between the first outside air and a refrigerant, and a heat exchanger that is provided in the air conditioning flow path downstream of the first heat exchanger and performs heat exchange between the first outside air that has passed through the first heat exchanger and a second outside air that is part of the outside air and has not passed through the first heat exchanger, wherein the evaporation temperature of the refrigerant in the first heat exchanger is set to a value between -1°C and 9°C, and the flow velocity of the first outside air when passing through the first heat exchanger is set to a value between 0.5 m / s and 2.5 m / s. According to this aspect, by setting the flow velocity of the first outdoor air when passing through the first heat exchanger to 0.5 m / s or more and 2.5 m / s or less, even if the evaporation temperature of the refrigerant in the first heat exchanger is set to -1°C or more and 9°C or less, the first outdoor air can be easily cooled to a desired temperature. In addition, by performing heat exchange in the second heat exchanger between the first outdoor air that has passed through the first heat exchanger and the second outdoor air that has not passed through the first heat exchanger, the temperature of the first outdoor air can be increased and the relative humidity of the first outdoor air can be reduced. Therefore, condensation around the outlet of the first outdoor air can be suppressed. Effect of the Invention

[0015] According to each of the above aspects, it is possible to lower the blowing temperature of the conditioned air introduced into the indoor space while ensuring operational reliability. [Brief description of the drawings]

[0016] [Figure 1] 1 is a perspective view of an outside air treatment device according to an embodiment; [Diagram 2] FIG. 2 is a view taken along the arrow II in FIG. [Diagram 3]1 is a schematic configuration diagram of an outside air treatment device according to an embodiment. [Figure 4] FIG. 2 is a side view of the air conditioning unit according to the embodiment. [Diagram 5] FIG. 2 is a front view of the evaporator according to the embodiment. [Figure 6] FIG. 2 is a front view of the reheater according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Next, an embodiment of the present invention will be described with reference to the drawings. In the embodiments and modifications described below, the same reference numerals may be used to designate corresponding configurations, and the description may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly indicate such arrangements, but also indicate a state in which the two surfaces are relatively displaced with an angle or distance to the extent that the same function is obtained. In this embodiment, "facing" does not only mean a case in which the orthogonal directions (normal directions) of the two surfaces are aligned with each other, but also includes a case in which the orthogonal directions intersect with each other.

[0018] [Outside air treatment device 1] Fig. 1 is a perspective view of the outside air treatment device 1. Fig. 2 is a view taken along the line II in Fig. 1. 1 and 2 is installed in an outdoor space of a factory, facility, etc. The outdoor air processing device 1 cools and dehumidifies the outdoor air taken in from outdoors, and supplies it to an indoor space of the facility.

[0019] FIG. 3 is a schematic diagram of the outside air treatment device 1. As shown in FIG. As shown in FIG. 3, the outdoor air processing device 1 includes a refrigeration cycle circuit 10 and an air conditioning circuit 11.

[0020] <Refrigeration cycle circuit 10> The refrigeration cycle circuit 10 circulates a refrigerant (heat medium) as a working fluid while changing its phase between a gaseous refrigerant and a liquid refrigerant by exchanging heat with the outside air. In the refrigeration cycle circuit 10 of this embodiment, an HFO refrigerant is preferably used as the refrigerant. However, an HFC refrigerant or a natural refrigerant may also be used as the refrigerant.

[0021] The refrigeration cycle circuit 10 includes a compressor 21, an oil separator 22, a condenser 23, a receiver 24, an expansion valve 25, and an evaporator (first heat exchanger) 26. The compressor 21, the oil separator 22, the condenser 23, the receiver 24, the expansion valve 25, and the evaporator 26 are provided in order on a refrigerant main flow path 27 in the flow direction of the refrigerant.

[0022] The compressor 21 compresses the low-pressure gas refrigerant introduced into the compressor 21 to produce a high-temperature and high-pressure gas refrigerant. In this embodiment, for example, a reciprocating compressor is used as the compressor 21. However, the compressor 21 is not limited to the reciprocating type, and a scroll type, rotary type, screw type, or the like may also be used. The oil separator 22 is provided downstream of the compressor 21 in the refrigerant main flow path 27. The oil separator 22 separates the lubricating oil of the compressor 21 that is discharged from the compressor 21 together with the gaseous refrigerant, from the gaseous refrigerant that has passed through the compressor 21. Note that the installation of the oil separator 22 is not an essential component depending on the performance and characteristics of the compressor 21.

[0023] The condenser 23 is provided on the refrigerant main flow path 27, downstream of the oil separator 22. The condenser 23 performs heat exchange between the refrigerant and outside air, thereby dissipating heat from the high-temperature, high-pressure gas refrigerant fed from the compressor 21, and converting the high-temperature, high-pressure gas refrigerant into a high-pressure liquid refrigerant. In this embodiment, the condenser 23 is, for example, a microchannel heat exchanger.

[0024] The receiver 24 is provided on the refrigerant main flow path 27 downstream of the condenser 23. The receiver 24 stores the refrigerant condensed in the condenser 23 (high-pressure liquid refrigerant). The expansion valve 25 is provided on the refrigerant main flow path 27 downstream of the receiver 24. The expansion valve 25 reduces the pressure of the high-pressure liquid refrigerant sent from the receiver 24, and converts the high-pressure liquid refrigerant into a low-temperature and low-pressure gas-liquid mixed refrigerant. The expansion valve 25 is preferably an electronic expansion valve capable of adjusting the flow rate according to the cooling load.

[0025] The evaporator 26 is provided between the expansion valve 25 and the compressor 21 on the refrigerant main flow path 27. The evaporator 26 vaporizes the low-temperature, low-pressure gas-liquid mixed refrigerant fed from the expansion valve 25, and converts the low-temperature, low-pressure gas-liquid mixed refrigerant into low-pressure gas refrigerant. When the low-pressure gas-liquid mixed refrigerant vaporizes, the evaporator 26 removes heat of vaporization from the surroundings. This cools the outside air around the evaporator 26. The low-pressure gas refrigerant that has passed through the evaporator 26 is taken back into the compressor 21. Details of the evaporator 26 will be described later.

[0026] The refrigeration cycle circuit 10 of this embodiment is provided with a refrigerant bypass flow path 28. The refrigerant bypass flow path 28 connects a portion of the refrigerant main flow path 27 located between the compressor 21 and the evaporator 26 and a portion located between the oil separator 22 and the condenser 23. That is, the refrigerant bypass flow path 28 is a flow path for diverting high-temperature and high-pressure gas refrigerant (hot gas) discharged from the compressor 21 to the downstream side of the evaporator 26 without condensing it in the condenser 23, in a situation where the cooling load is small, such as in winter. This ensures the amount of refrigerant circulating in the compressor 21, allowing operation to continue regardless of fluctuations in the cooling load.

[0027] <Air conditioning circuit 11> The air conditioning circuit 11 is a circuit for adjusting the temperature and humidity of the outside air to be supplied to an indoor space. The air conditioning circuit 11 includes an air conditioning main flow path 31 and an air conditioning bypass flow path 32. An eliminator 33, a filter 34, and a fan 35 are provided on the air conditioning main flow path 31.

[0028] The eliminator 33 is a so-called gas-liquid separator. The eliminator 33 is provided at the upstream end of the air conditioning main flow path 31. The eliminator 33 captures moisture such as rainwater from the outside air introduced into the air conditioning main flow path 31 during the process of the outside air passing through. The filter 34 is provided on the air conditioning main flow path 31, downstream of the eliminator 33. The filter 34 captures dust and the like from the outside air that has passed through the eliminator 33 during the process of the outside air passing through.

[0029] The fan 35 is provided on the air conditioning main flow path 31, downstream of the filter 34. The fan 35 sends outside air toward the downstream side of the air conditioning main flow path 31. In this embodiment, the fan 35 is, for example, a centrifugal fan.

[0030] In the air conditioning main flow path 31, an evaporator 26 is disposed downstream of the fan 35. When the outside air flowing through the air conditioning main flow path 31 passes through the evaporator 26, heat is exchanged between the outside air flowing through the evaporator 26 and the low-temperature, low-pressure gas-liquid mixed refrigerant flowing inside the evaporator 26. In the air conditioning main flow path 31, a reheater (second heat exchanger) 37 is disposed downstream of the evaporator 26. The reheater 37 exchanges heat between the outside air that has passed through the evaporator 26 (first outside air) and the outside air that has not passed through the evaporator 26 (second outside air).

[0031] The air conditioning bypass flow path 32 is a flow path for causing a portion of the outside air flowing through the air conditioning main flow path 31 to bypass the evaporator 26. Specifically, the air conditioning bypass flow path 32 includes an inlet flow path 32a and an outlet flow path 32b. The inlet flow passage 32 a connects a portion of the air conditioning main flow passage 31 that is located between the fan 35 and the evaporator 26 and an inlet portion of the reheater 37 . The outlet flow path 32b connects an outlet portion of the reheater 37 and a portion of the air conditioning main flow path 31 that is located between the filter 34 and the fan 35. That is, the reheater 37 reheats the outside air cooled by the evaporator 26 by circulating the outside air that bypasses the evaporator 26 and flows on the air conditioning bypass flow path 32. The details of the reheater 37 will be described later.

[0032] In the outdoor air treatment device 1 of this embodiment, the refrigeration cycle circuit 10 and the air conditioning circuit 11 are accommodated in a refrigeration case 50 and an air conditioning case 51, thereby forming a refrigeration unit 100 and an air conditioning unit 101.

[0033] <Refrigeration unit 100> 1 and 2, the freezer case 50 constituting the exterior of the freezer unit 100 is installed on the installation surface F of the outside air processing device 1 via a stand 53. In the following description, the direction perpendicular to the installation surface F is defined as the up-down direction (arrow UP indicates the upward direction), and two directions perpendicular to each other as viewed from the up-down direction are defined as the front-rear direction (arrow FR indicates the forward direction) and the left-right direction (arrow LH indicates the left direction). In the front-rear direction, the direction approaching an inlet 70 and an outlet 71 of the air conditioning case 51, which will be described later, is defined as the forward direction, and the direction away from the inlet 70 and the outlet 71 is defined as the rearward direction.

[0034] The freezer case 50 is formed in a rectangular parallelepiped shape with the longitudinal direction being the front-rear direction. The inside of the freezer case 50 is divided into an upper space 56 and a lower space 57 by a partition wall 55. The lower space 57 houses the compressor 21, the oil separator 22, and the receiver 24 (see FIG. 3) of the refrigeration cycle circuit 10.

[0035] The condenser 23 is housed in the upper space 56. Specifically, an opening 58a is formed in a side wall portion 58 facing the left-right direction at the top of the freezer case 50. The upper space 56 communicates with the outside of the freezer unit 100 through the opening 58a. A fan 60 is provided in a top wall portion 59 of the freezer case 50. That is, outside air taken in through the opening 58a by the operation of the fan 60 passes through the condenser 23, and then is discharged to the outside of the freezer unit 100 from the upper space 56. The freezer case 50 is appropriately provided with an opening / closing door for maintenance of the devices housed in the freezer case 50.

[0036] <Air Conditioning Unit 101> The air conditioning unit 101 is disposed on one side (the right side) in the left-right direction with a gap therebetween with respect to the refrigeration unit 100. An expansion valve 25 is provided in a portion of the refrigerant main flow path 27 that is located between the air conditioning unit 101 and the refrigeration unit 100 (see FIG. 2).

[0037] FIG. 4 is a side view of the air conditioning unit 101. As shown in FIG. 4, the air conditioning case 51 constituting the exterior of the air conditioning unit 101 is installed on an installation surface F via a stand 53. The air conditioning case 51, like the freezer case 50, is formed in a rectangular parallelepiped shape with the longitudinal direction being the front-rear direction. An inlet 70 and an outlet 71 are formed in the front wall 51a of the air conditioning case 51. The inlet 70 opens in the front-rear direction at the bottom of the front wall 51a. Meanwhile, the outlet 71 opens in the front-rear direction at the top of the front wall 51a. The air conditioning case 51 is appropriately provided with an opening and closing door for maintenance of the devices stored in the air conditioning case 51.

[0038] A partition wall 73 is provided inside the air conditioning case 51 to separate the inlet 70 and the outlet 71. The partition wall 73 extends rearward from the front wall 51a while being supported by both left and right side walls 51b, 51c (see FIG. 2) of the air conditioning case 51. The rear end of the partition wall 73 is spaced apart from the rear wall 51d of the air conditioning case 51. Therefore, inside the air conditioning case 51, a U-shaped air conditioning main flow path 31 is formed in a side view. Specifically, the air conditioning main flow path 31 includes an outgoing path 31a extending rearward from the inlet 70, a return path 31b extending upward from the downstream end of the outgoing path 31a, and a return path 31c extending rearward from the downstream end of the return path 31b toward the outlet 71. However, the shape of the air conditioning main flow path 31 can be changed as appropriate according to the layout of the inlet 70 and the outlet 71.

[0039] In the outward path 31a, the above-mentioned eliminator 33 and filter 34 are arranged in this order. A fan 35 is disposed at the boundary between the outgoing path 31a and the return path 31b. The return line 31c is provided with the evaporator 26 and the reheater 37 in that order. A refrigerant leakage sensor 75 is provided in a portion of the return line 31c between the reheater 37 and the air outlet 71. The refrigerant leakage sensor 75 detects leakage of refrigerant into the main refrigerant flow path 27.

[0040] <Evaporator 26> FIG. 5 is a front view of the evaporator 26. 5 is provided so as to block the return path 31c (see FIG. 2). The evaporator 26 includes a plurality of evaporator fins (first fins) 80 and an evaporator pipe (first pipe) 81. Each evaporator fin 80 is formed in a thin plate shape from a material with excellent thermal conductivity, such as aluminum. Each evaporator fin 80 is arranged at intervals in the left-right direction (first direction), for example. That is, the evaporator fins 80 are lined up in a direction perpendicular to the flow direction of the outside air in the return path 31c. In the return path 31c, the outside air passes through the gaps between adjacent evaporator fins 80.

[0041] A plurality of through holes 80a are formed in each evaporator fin 80, penetrating the evaporator fin 80 in the thickness direction (left-right direction). The through holes 80a are arranged, for example, in a staggered pattern.

[0042] The evaporator pipe 81 constitutes a part of the refrigerant main flow path 27. That is, the refrigerant that has passed through the expansion valve 25 flows through the evaporator pipe 81. The evaporator pipe 81 penetrates through the through holes 80a that face each other in the left-right direction in the adjacent evaporator fins 80, and is attached to each evaporator fin 80 by being folded back on the outside of the stacked evaporator fins 80.

[0043] <Reheater 37> FIG. 6 is a front view of the reheater 37. 6 is provided in the return path 31c at a portion located downstream of the evaporator 26 so as to block the return path 31c. The reheater 37 includes a plurality of reheater fins 90 and a reheater pipe 91. The reheater fins 90 are arranged at intervals in the left-right direction (second direction) similarly to the evaporator fins 80. That is, in the return path 31c, the outside air passes through the gaps between the adjacent reheater fins 90.

[0044] A plurality of through holes 90a are formed in each reheater fin 90, penetrating the reheater fin 90 in the thickness direction (left-right direction). The through holes 90a are arranged, for example, in a staggered pattern.

[0045] The reheater pipe 91 constitutes a part of the air conditioning bypass flow path 32. That is, the reheater pipe 91 connects between the inlet flow path 32a and the outlet flow path 32b, and outside air that has bypassed the evaporator 26 flows through the reheater pipe 91. As shown in FIG. 2 and FIG. 4, the upstream end of the inlet flow path 32a is provided in a portion of the return path 31c that is located laterally with respect to the evaporator 26. The downstream end of the inlet flow path 32a is connected to the upstream end of the reheater pipe 91. On the other hand, the upstream end of the outlet flow path 32b is connected to the downstream end of the reheater pipe 91. As shown in FIG. 4, the downstream end of the outlet flow path 32b opens to a portion of the outward path 31a that is located between the eliminator 33 and the filter 34. That is, in this embodiment, at least a part of the outside air that has passed through the reheater pipe 91 is configured to circulate inside the air conditioning case 51.

[0046] The reheater pipe 91 passes through the through holes 90a facing each other in the left-right direction in adjacent reheater fins 90, and is attached to each reheater fin 90 by being folded back on the outside of the stacked reheater fins 90.

[0047] 5 and 6, the distance (fin pitch D1) between adjacent evaporator fins 80 is wider than the distance (fin pitch D2) between adjacent reheater fins 90. In this embodiment, the fin pitch D1 is preferably set to 4 mm or more and 7 mm or less. On the other hand, the fin pitch D2 is preferably set to 2.5 mm or more and less than 4 mm.

[0048] 2, when viewed from the flow direction (front-rear direction) of the outside air in the return path 31c, the outer shape of the evaporator 26 in a front view is larger than the outer shape of the reheater 37 in a front view. However, the outer shapes of the evaporator 26 and the reheater 37 in a front view can be changed as appropriate. In addition, the dimensions of the evaporator 26 and the reheater 37 in the flow direction of the outside air in the return path 31c may be different from each other.

[0049] [Outside air processing method] Next, a description will be given of an outdoor air processing method using the above-mentioned outdoor air processing device 1. The following mainly describes the operation of the air conditioning unit 101 in a state where the refrigeration cycle circuit 10 is operating normally. In the air conditioning unit 101, the fan 35 is operated to introduce outside air into the air conditioning case 51 through the inlet 70. The outside air introduced into the air conditioning case 51 has moisture, dust, and the like captured as it passes through the eliminator 33 and the filter 34 in the outward path 31a, and then flows into the return path 31c via the return path 31b (see arrow F1).

[0050] The outside air flowing through the return path 31c branches upstream of the evaporator 26 into conditioned air (first outside air: see arrow F2) that passes through the evaporator 26 and bypass air (second outside air: see arrow F3) that bypasses the evaporator 26. When the conditioned air passes between adjacent evaporator fins 80, heat is exchanged between the conditioned air and the low-temperature, low-pressure refrigerant in a gas-liquid mixture state that flows through the evaporator pipe 81. This cools the conditioned air. In addition, as the conditioned air is cooled, the absolute humidity of the conditioned air decreases, and the conditioned air is dehumidified.

[0051] Here, the flow velocity of the conditioned air passing through the evaporator 26 is preferably set to 0.5 m / s or more and 2.5 m / s or less. This makes it easy to cool the conditioned air to a desired temperature even when the evaporation temperature of the refrigerant in the evaporator 26 is set to -1° C. or more and 9° C. or less. The flow velocity of the conditioned air can be set, for example, by adjusting the volume of the return path 31b according to the rated torque of the fan 35.

[0052] The conditioned air that has passed through the evaporator 26 exchanges heat with the bypass air as it passes through the adjacent reheater fins 90. This heats the conditioned air. As the conditioned air is heated, the relative humidity of the conditioned air decreases. The bypass air that has passed through the reheater pipe 91 of the reheater 37 is returned to the outward path 31a via the outlet flow path 32b, and then sent again to the return path 31c by the fan 35.

[0053] The conditioned air that has passed through the reheater 37 is blown out from the air conditioning unit 101 through the air outlet 71. The conditioned air blown out from the air conditioning unit 101 is supplied to an indoor space through an appropriate duct or the like.

[0054] As described above, the outdoor air treatment device 1 of this embodiment is configured to include an evaporator (first heat exchanger) 26 that is provided in the main air conditioning flow path 31 and cools the air-conditioned air by exchanging heat between the air-conditioned air and the refrigerant, and a reheater (second heat exchanger) 37 that exchanges heat between the air-conditioned air that has passed through the evaporator 26 and bypass air that is part of the outdoor air and has not passed through the evaporator 26. According to this configuration, in the reheater 37, heat exchange is performed between the conditioned air (first outside air) that has passed through the evaporator 26 and the bypass air (second outside air) that has not passed through the evaporator 26, thereby making it possible to increase the temperature of the conditioned air and decrease the relative humidity of the conditioned air. Therefore, condensation around the air outlet 71 of the conditioned air can be suppressed.

[0055] Here, in the outside air treatment device 1 of this embodiment, the fin pitch D1 of the evaporator fins 80 is wider than the fin pitch D2 of the reheater fins 90. According to this configuration, by making the fin pitch D1 wider than the fin pitch D2, even if condensation occurs on the surface of the evaporator 26 (the evaporator fins 80, the evaporator pipe 81, etc.) when the conditioned air passes through the evaporator 26, the water is likely to drop between adjacent evaporator fins 80. Therefore, it is possible to prevent water from staying between adjacent evaporator fins 80. In addition, even if frost forms on the evaporator fins 80, the water staying between adjacent evaporator fins 80 can prevent the flow of conditioned air from being obstructed between the adjacent evaporator fins 80. In this case, the flow velocity of the conditioned air passing through the evaporator 26 can be reduced, so that the desired temperature can be achieved even if the approach temperature is low. As a result, frost formation on the surfaces of the evaporator fins 80 can be more reliably suppressed. In addition, the approach temperature can be reduced, so the cycle efficiency of the refrigerator is improved. This makes it easier to cool the conditioned air to the desired temperature while ensuring operational reliability.

[0056] In the outside air treatment device 1 of this embodiment, the fin pitch D1 is set to 4 mm or more and 7 mm or less. According to this configuration, by setting the fin pitch D1 to 4 mm or more, even if frost forms on the evaporator fins 80, it is possible to prevent the flow of conditioned air between adjacent evaporator fins 80 from being obstructed. On the other hand, by setting the fin pitch D1 to 7 mm or less, the evaporator 26 can be prevented from becoming large.

[0057] In the outside air treatment device 1 of this embodiment, the outer shape of the evaporator 26 in a front view is larger than the outer shape of the reheater 37 in a front view. According to this configuration, even if the fin pitch D1 is widened, it is easy to ensure the number of evaporator fins 80, and the heat exchange efficiency in the evaporator 26 is easy to ensure.

[0058] The outside air treatment device 1 of this embodiment is configured to use an HFO refrigerant as the refrigerant. According to this configuration, the global warming potential (GWP) can be reduced, making it possible to suppress global warming.

[0059] In the outside air treatment device 1 of this embodiment, the evaporation temperature of the refrigerant in the evaporator 26 is set to be in the range of -1°C to 9°C. According to this configuration, by setting the evaporation temperature of the refrigerant to −1° C. or higher, frost formation on the surfaces of the evaporator fins 80 can be suppressed. On the other hand, by setting the evaporation temperature of the refrigerant to 9°C or lower, the blowing temperature of the conditioned air can be lowered. In this case, by setting the flow velocity of the conditioned air when passing through the evaporator 26 to 0.5 m / s or more and 2.5 m / s or less, the conditioned air can be easily cooled to a desired temperature (for example, 0°C to 15°C) even when the evaporation temperature of the refrigerant in the evaporator 26 is set to -1°C or more and 9°C or less. Furthermore, by performing heat exchange in the reheater 37 between the conditioned air that has passed through the evaporator 26 and the bypass air that bypasses the evaporator 26, the temperature of the conditioned air can be increased and the relative humidity of the conditioned air can be reduced. Therefore, condensation around the outlet of the conditioned air can be suppressed.

[0060] The outdoor air treatment device 1 of this embodiment is configured to include an air conditioning unit 101 having an air conditioning case 51 in which a main air conditioning flow path 31 is formed, and an evaporator 26 and a reheater 37 housed in the air conditioning case 51, a refrigeration unit 100 having a freezer case 50 in which a compressor 21 and a condenser 23 are housed and arranged away from the air conditioning unit 101, and an expansion valve (expansion device) 25 arranged between the air conditioning unit 101 and the refrigeration unit 100. According to this configuration, by making the air conditioning unit 101 and the refrigeration unit 100 into separate cases, it is possible to pre-assemble each unit in a factory. Therefore, at the site, each unit is installed and then the installation of the outside air processing device 1 is completed by assembling the piping and the like. This makes it possible to improve the ease of transportation and reduce the labor required for installation work. Furthermore, by making the air conditioning unit 101 and the refrigeration unit 100 into separate cases, it is also possible to improve maintainability.

[0061] The outside air treatment device 1 of this embodiment is configured such that a refrigerant leakage sensor (sensor) 75 for detecting refrigerant leakage is provided in a portion located downstream of the reheater 37 in the main air conditioning flow path 31. According to this configuration, even when a slightly flammable refrigerant such as an HFO refrigerant is used, any refrigerant leakage can be detected and appropriate measures such as shutting down or treating the system can be taken, thereby preventing refrigerant leakage and ensuring safety.

[0062] (Other variations) Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the attached claims. In the above embodiment, the freezing case 50 and the air conditioning case 51 are arranged apart from each other, but the present invention is not limited to this configuration. The refrigeration cycle circuit 10 and the air conditioning circuit 11 may be housed together in a single casing. In the above embodiment, the configuration in which the evaporation temperature of the refrigerant in the evaporator 26 is set to be equal to or higher than -1°C and equal to or lower than 9°C has been described, but the configuration is not limited to this. The evaporation temperature of the refrigerant in the evaporator 26 can be changed as appropriate. In the above embodiment, the refrigeration cycle circuit 10 is of a direct expansion type (a type in which the evaporator 26 is in direct contact with the outside air), but the present invention is not limited to this type. The refrigeration cycle circuit 10 may be of an indirect expansion type (a type in which a heat medium is interposed between the evaporator 26 and the outside air), for example.

[0063] In the above embodiment, a configuration has been described in which part of the outside air flowing through the air conditioning main flow path 31 is supplied to the reheater 37 by bypassing the evaporator 26, but the present invention is not limited to this configuration. The outside air supplied to the reheater 37 may be a separate circuit from the air conditioning main flow path 31. In other words, any configuration may be used as long as the outside air supplied to the reheater 37 does not pass through the evaporator 26. In the above embodiment, the arrangement direction (first direction) of the evaporator fins 80 and the arrangement direction (second direction) of the reheater fins 90 are the same direction, but the present invention is not limited to this configuration. The arrangement direction of the evaporator fins 80 and the arrangement direction of the reheater fins 90 may intersect with the flow direction of outside air passing through them.

[0064] In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0065] 1: Outdoor air treatment device 3: Condenser 21: Compressor 23: Condenser 26: Evaporator (first heat exchanger) 31: Main air conditioning channel (air conditioning channel) 37: Reheater (second heat exchanger, heat exchanger) 50: Freezer case 51: Air conditioning case 75: Refrigerant leak sensor (sensor) 80: Evaporator fin (first fin) 81: Evaporator pipe (first pipe) 90: Reheater fin (second fin) 91: Reheater pipe (second pipe) 100: Refrigeration unit 101: Air conditioning unit

Claims

1. an air conditioning flow path through which first outside air flows among outside air taken in from outdoors; a first heat exchanger provided in the air conditioning flow path and configured to cool the first outside air by exchanging heat between the first outside air and a heat medium; a second heat exchanger that is provided downstream of the first heat exchanger in the air conditioning flow path and performs heat exchange between the first outside air that has passed through the first evaporator and a second outside air that has not passed through the first heat exchanger, The first heat exchanger is a plurality of first fins provided at intervals from one another in a first direction intersecting a flow direction of the first outside air in the air conditioning flow path; a first pipe passing through the first fins and through which a heat medium flows; The second heat exchanger is A plurality of second fins are provided at intervals in a second direction intersecting the flow direction; a second pipe penetrating the second fins and through which the second outside air flows, The outside air treatment device, wherein the distance between adjacent first fins is wider than the distance between adjacent second fins.

2. The outside air treatment device according to claim 1 , wherein the distance between adjacent first fins is set to be equal to or greater than 4 mm and equal to or less than 7 mm.

3. The outside air treatment device according to claim 1 or 2, wherein an outer shape of the first heat exchanger as viewed from the flow direction is larger than an outer shape of the second heat exchanger as viewed from the flow direction.

4. The outside air treatment device according to claim 1 or 2, wherein the heat medium is an HFO refrigerant.

5. The outside air treatment device according to claim 4, wherein the evaporation temperature of the HFO refrigerant in the first heat exchanger is set to be in the range of -1°C to 9°C.

6. an air conditioning unit having an air conditioning case in which the air conditioning flow path is formed, and the first heat exchanger and the second heat exchanger housed in the air conditioning case; a refrigeration unit having a refrigeration case in which a compressor that compresses a heat medium and a condenser that dissipates heat from the heat medium compressed by the compressor are housed, the refrigeration unit being disposed apart from the air conditioning unit; 3. The outside air treatment device according to claim 1, further comprising: an expansion device disposed between the air conditioning unit and the refrigeration unit, the expansion device connecting the condenser and the first heat exchanger.

7. 3. The outside air treatment device according to claim 1, wherein a sensor for detecting leakage of the heat medium is provided in a portion of the air conditioning flow path that is located downstream of the second heat exchanger.

8. an air conditioning flow path through which first outside air flows among outside air taken in from outdoors; an evaporator provided in the air conditioning flow path and configured to cool the first outside air by performing heat exchange between the first outside air and a refrigerant; a heat exchanger that is provided downstream of the evaporator in the air conditioning flow path and performs heat exchange between the first outside air that has passed through the evaporator and a second outside air that has not passed through the evaporator, The outside air processing method includes setting the evaporation temperature of the refrigerant in the evaporator to -1°C or higher and 9°C or lower, and setting the flow velocity of the first outside air passing through the evaporator to 0.5 m / s or higher and 2.5 m / s or lower.

Images