Refrigeration system

Abstract

To provide a refrigeration system capable of operating a refrigeration circuit for air-conditioning an object space and a humidity control unit for controlling humidity in the object space with high efficiency.SOLUTION: A refrigeration system 1 includes: a refrigeration circuit 2 having a compressor, a heat source side heat exchanger, a gas liquid separator 16, a plurality of utilization side heat exchangers and a refrigerant flow passage for connecting these devices; and a humidity control unit 3 that controls humidity in an object space air-conditioned by at least one of the utilization side heat exchangers. The humidity control unit 3 includes: an outside-air air course 152 in which air outside the object space flows; an inside-air air course 153 in which the air taken in from the object space flows toward the object space; and a desiccant rotor 160 disposed astride the outside-air air course 152 and the inside-air air course 153 and driven to rotate. The heat source side heat exchanger is disposed in the outside-air air course 152. In a dehumidification mode of dehumidifying the object space by using the humidity control unit 3, the heat source side heat exchanger is caused to function as a condenser.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to refrigeration systems. [Background technology]

[0002] Patent Document 1 discloses a ventilation system that dehumidifies indoor air using a dehumidifying agent and regenerates the dehumidifying agent by irradiating the dehumidifying agent with microwaves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-170786 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a refrigeration system capable of operating, with high efficiency, a refrigeration circuit that conditions the air in a target space and a humidity control unit that controls the humidity in the target space. [Means for solving the problem]

[0005] A refrigeration system according to the present disclosure includes a refrigeration circuit having a compressor, a heat source side heat exchanger, a gas-liquid separator, a plurality of use side heat exchangers, and a refrigerant flow path connecting these, and a humidity control unit that controls humidity in a target space that is air-conditioned by at least one of the use side heat exchangers, wherein the refrigeration circuit includes a first flow path connecting the heat source side heat exchanger and the gas-liquid separator and in which a first heat exchanger is provided, a second flow path connecting the heat source side heat exchanger and the gas-liquid separator and in which a second heat exchanger is provided, a first throttle unit that is provided upstream of the first heat exchanger in the first flow path and that adjusts the flow rate of the refrigerant flowing to the first heat exchanger, and a second throttle unit that is provided upstream of the second heat exchanger in the second flow path and that adjusts the flow rate of the refrigerant flowing to the second heat exchanger. and a second throttling section that adjusts the flow rate of the refrigerant that is introduced into the target space, and the humidity control unit comprises an outside air duct through which air outside the target space flows, an inside air duct through which air taken in from the target space flows toward the target space, and a desiccant rotor that is disposed across the outside air duct and the inside air duct and is driven to rotate, the first heat exchanger and the second heat exchanger are disposed in the inside air duct, and air that has undergone heat exchange by the heat source side heat exchanger is sent to the desiccant rotor through the outside air duct, and in a dehumidification mode in which the humidity control unit dehumidifies the target space, the heat source side heat exchanger functions as a condenser, and the first throttling section and the second throttling section are set to a state that is narrower than a fully open state. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to operate a refrigeration circuit that conditions the air in a target space and a humidity control unit that controls the humidity in the target space with high efficiency. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a refrigeration circuit of a refrigeration system according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing a refrigeration circuit of a refrigeration system according to a first embodiment. [Figure 3] 1 is a diagram showing a schematic configuration of a humidity control unit; [Figure 4] Psychrometric chart showing the state of air in the humidity control unit [Figure 5]FIG. 10 is a diagram showing another example of the configuration of a refrigeration circuit. [Figure 6] Refrigeration system block diagram [Figure 7] Flowchart showing an example of operation of a refrigeration system [Figure 8] Flowchart showing an example of operation of a refrigeration system [Figure 9] FIG. 10 is a diagram showing a refrigeration circuit of a refrigeration system according to a second embodiment. [Figure 10] FIG. 10 is a diagram showing a refrigeration circuit of a refrigeration system according to a second embodiment. [Figure 11] FIG. 10 is a diagram showing a refrigeration circuit of a refrigeration system according to a second embodiment. [Figure 12] Psychrometric chart showing the state of air in the humidity control unit DETAILED DESCRIPTION OF THE INVENTION

[0008] (Findings that formed the basis of this disclosure) At the time when the inventors arrived at the present disclosure, there was a technology that used a dehumidifying agent to control the humidity of a target space. The inventors discovered that when dehumidifying a target space using such a technology, energy was consumed by irradiating microwaves, etc. to regenerate the dehumidifying agent, resulting in poor energy efficiency. In order to solve this problem, the inventors came up with the subject matter of the present disclosure. Therefore, the present disclosure provides a refrigeration system capable of operating a refrigeration circuit that conditions the air in a target space and a humidity control unit that controls the humidity in the target space with high efficiency.Furthermore, the present disclosure provides a refrigeration system that reduces the air conditioning load in the target space by controlling the humidity in the target space using refrigerant in the refrigeration circuit, thereby reducing the overall power consumption of the air conditioning and refrigeration equipment and maintaining comfort in the target space.

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to the drawings. [1-1. Refrigeration system configuration] [1-1-1. Refrigeration circuit configuration] 1 and 2 are circuit diagrams showing a refrigeration system 1 in embodiment 1. In FIG. 1, FIG. 2, and each figure described later, for ease of explanation, an opening / closing device in an open state is shown in white, and an opening / closing device in a closed state and an expansion mechanism are shown in black. An opening / closing device is a device that can close a pipe through which a refrigerant flows in the refrigeration system 1, and specifically refers to a shutoff valve, a throttling mechanism, an expansion mechanism, etc. In FIG. 1, FIG. 2, and each figure described later, for ease of explanation, of the refrigerant pipes shown, pipes through which a refrigerant flows are shown in thick lines, and pipes through which a refrigerant does not flow are shown in thin lines.

[0011] As shown in Figures 1 and 2, the refrigeration system 1 comprises an outdoor unit 10, an indoor unit 20, and a cooling equipment 30, which are connected to each other by refrigerant piping to form a refrigeration circuit 2 that functions as a flow path through which the refrigerant flows. In this embodiment, the refrigerant used in the refrigeration circuit 2 is, for example, carbon dioxide refrigerant (R744), which is a natural refrigerant that is non-flammable and non-toxic.

[0012] The indoor unit 20 is equipped with an indoor heat exchanger 22, which is a user-side heat exchanger. The indoor unit 20 conditions the air inside a store, which is a space to be conditioned, based on a temperature setting set by a user in a store such as a convenience store or supermarket. The space to be conditioned corresponds to the "target space" in this disclosure. The indoor heat exchanger 22 corresponds to the "air conditioning heat exchanger" in this disclosure. The refrigeration equipment 30 includes a user-side heat exchanger, refrigeration heat exchanger 32. The refrigeration equipment 30 cools the interior of a refrigerated showcase or a freezer showcase, which is a cooling storage facility installed in a store, based on a temperature setting set by a user.

[0013] When these set temperatures are set, the evaporation temperature of the indoor heat exchanger 22 or the evaporation temperature of the cooling heat exchanger 32 is set. In the refrigeration system 1, the air that has exchanged heat with the indoor heat exchanger 22 or the cooling heat exchanger 32 at the evaporation temperature set in this way is sent to the space to be conditioned or the inside of the cooling equipment 30, so that the temperature of the space to be conditioned or the inside of the cooling equipment 30 becomes the set temperature.

[0014] The refrigeration system 1 includes a humidity control unit 3. The humidity control unit 3 is a device that controls the humidity of the air in a target space. Humidity control includes at least one of dehumidification and humidification. In this embodiment, the target space for which the humidity control unit 3 controls the humidity is the same space as the space to be conditioned by the indoor unit 20. The configuration of the humidity control unit 3 will be described later with reference to FIG. 3.

[0015] The refrigeration system 1 has a function of cooling the interior of a refrigerated showcase or a freezer showcase using a cooling equipment 30, a function of heating and cooling a target space using an indoor unit 20, and a function of controlling the humidity of the target space using a humidity control unit 3. The refrigeration system 1 of this embodiment can be switched between a plurality of operating modes, specifically a cooling mode, a cooling and dehumidification mode, a heating mode, a heating and dehumidification mode, and a space dehumidification mode. In the cooling mode, the refrigeration system 1 performs cooling using the indoor unit 20, and in the cooling and dehumidification mode, the refrigeration system 1 performs cooling using the indoor unit 20 and dehumidification using the humidity control unit 3. In the heating mode, the refrigeration system 1 performs heating using the indoor unit 20, and in the heating and dehumidification mode, the refrigeration system 1 performs heating using the indoor unit 20 and dehumidification using the humidity control unit 3. The cooling and dehumidification mode, the heating and dehumidification mode, and the space dehumidification mode correspond to the "dehumidification mode" of the present disclosure.

[0016] Figure 1 shows the state of each opening and closing device when the refrigeration system 1 operates in cooling and dehumidifying mode, and Figure 2 shows the state of each opening and closing device when the refrigeration system 1 operates in heating and dehumidifying mode, and the direction of refrigerant flow is indicated by arrows in these figures.

[0017] The outdoor unit 10 functions as a so-called heat source device. The outdoor unit 10 is formed by sequentially connecting multiple compressors, a first switching mechanism 50, an outdoor heat exchanger 15, a second switching mechanism 54, and a gas-liquid separator 16. The outdoor heat exchanger 15 corresponds to the "heat source-side heat exchanger" of the present disclosure.

[0018] The outdoor unit 10 is equipped with a two-stage compressor including a low-stage compressor 11 and two high-stage compressors 12, 12. This two-stage compressor is configured by connecting the low-stage compressor 11 and the high-stage compressors 12, 12 in series, and the two high-stage compressors 12, 12 are connected in parallel to the discharge side of the low-stage compressor 11. The low-stage compressor 11 and the high-stage compressor 12 are rotary compressors whose compression mechanisms are driven by, for example, a motor. The high-stage compressor 12 discharges refrigerant at a higher discharge pressure than the low-stage compressor 11.

[0019] An accumulator 13 is disposed between the discharge side of the low-stage compressor 11 and the high-stage compressor 12. The accumulator 13 functions as a flow divider that distributes the oil sent from the oil separator 14 to each of the high-stage compressors 12 approximately evenly.

[0020] An oil separator 14 is connected to the discharge side of the high-stage compressor 12. A first switching mechanism 50 is connected to the oil separator 14. That is, the first switching mechanism 50 is connected to the discharge pipe of the high-stage compressor 12 via the oil separator 14.

[0021] The oil separator 14 separates oil from the refrigerant discharged from the high-stage compressor 12 and stores the separated oil. The oil separator 14 is provided with an oil level sensor 83 that detects the amount of oil in the oil separator 14. The oil level sensor 83 detects, for example, when the height of the oil level in the oil separator 14 reaches a set height.

[0022] The oil separator 14 is connected to the low-stage compressor 11 and the accumulator 13 via an oil return pipe 46. The oil accumulated in the oil separator 14 is sent to the low-stage compressor 11 and the accumulator 13 via the oil return pipe 46. Flow control valves 47 and 48 are provided in the oil return pipe 46. The flow control valve 47 adjusts the amount of oil returned from the oil separator 14 to the high-stage compressor 12 by adjusting the flow rate of the oil-containing refrigerant sent from the oil return pipe 46 to the accumulator 13. The flow control valve 48 adjusts the amount of oil returned from the oil separator 14 to the low-stage compressor 11 by adjusting the flow rate of the oil-containing refrigerant sent from the oil return pipe 46 to the low-stage compressor 11. The flow control valves 47 and 48 are, for example, motor-operated valves.

[0023] A plurality of flow paths through which a refrigerant flows are connected to the first switching mechanism 50. The first switching mechanism 50 can switch, by an opening and closing device described below, between a state in which the refrigerant flows and a state in which the refrigerant is blocked for each of the flow paths connected to the first switching mechanism 50. For example, the first switching mechanism 50 switches the refrigerant sent from the high-stage compressor 12 in the refrigeration circuit 2 so that it flows through one of the plurality of flow paths.

[0024] The first switching mechanism 50 includes a pipe 40 that connects the oil separator 14 and the outdoor heat exchanger 15. A first cooling valve 51 is provided in the pipe 40. The first cooling valve 51 is located in the pipe 40 between the high-stage compressor 12 and the outdoor heat exchanger 15. The first cooling valve 51 is an opening / closing device that opens and closes the pipe 40. In the present embodiment, the first cooling valve 51 is an opening / closing device that can switch between an open state in which a refrigerant can flow through the pipe 40, and a closed state in which a refrigerant does not flow through the pipe 40.

[0025] In the piping 40, one end of a first heating piping 41 is connected between the oil separator 14 and the first cooling valve 51. A first heating valve 52 is provided on the first heating piping 41. The first heating valve 52 is an opening and closing device that opens and closes the first heating piping 41.

[0026] The other end of the first heating pipe 41 is connected to a pipe 71 that connects the indoor heat exchanger 22 of the indoor unit 20 and the suction side of the high-stage compressor 12. As a result, the discharge side of the high-stage compressor 12 is connected to the indoor heat exchanger 22 via the first heating pipe 41. An on-off valve 23 is provided in the pipe 71 between the point where the other end of the first heating pipe 41 is connected and the accumulator 13. The on-off valve 23 is an on-off device that opens and closes the pipe 71.

[0027] In the piping 40, one end of a first outdoor return piping 42 is connected between the first cooling valve 51 and the outdoor heat exchanger 15. An outdoor refrigerant return valve 53 is provided in the first outdoor return piping 42. The outdoor refrigerant return valve 53 is an opening and closing device that opens and closes the first outdoor return piping 42. The other end of the first outdoor return piping 42 is connected between the cooling-installation heat exchanger 32 of the refrigeration equipment 30 and the suction side of the low-stage compressor 11.

[0028] A cooling-use outlet-side pressure adjustment mechanism 33 is provided in the piping 72 between the point where the other end of the first outdoor return piping 42 is connected and the cooling-use heat exchanger 32. The cooling-use outlet-side pressure adjustment mechanism 33 is an opening / closing device that can change the opening degree from fully closed to fully open.

[0029] In this way, the first switching mechanism 50 is connected to the outdoor heat exchanger 15, the indoor heat exchanger 22, the refrigeration heat exchanger 32, and the low-stage compressor 11. The first switching mechanism 50 switches the refrigerant flow path in the refrigeration circuit 2 by opening and closing the first cooling valve 51, the first heating valve 52, and the outdoor refrigerant return valve 53. For example, the first switching mechanism 50 switches the flow path of the refrigerant discharged from the high-stage compressor 12 between a flow path that flows to the outdoor heat exchanger 15 and a flow path that flows to the indoor heat exchanger 22.

[0030] For example, when the refrigeration system 1 performs cooling operation, the refrigerant discharged from the high-stage compressor 12 flows to the outdoor heat exchanger 15. Also, when the refrigeration system 1 performs heating operation, the refrigerant discharged from the high-stage compressor 12 flows to the indoor heat exchanger 22. Also, when the refrigeration system 1 performs heating operation, the refrigerant discharged from the high-stage compressor 12 may flow to both the outdoor heat exchanger 15 and the indoor heat exchanger 22.

[0031] The first cooling valve 51, the first heating valve 52, and the outdoor refrigerant return valve 53 are electrically operated on-off valves that are opened and closed by an actuator or the like. Therefore, the first switching mechanism 50 can switch the refrigerant flow path in the refrigeration circuit 2 without stopping the low-stage compressor 11 and the high-stage compressor 12. That is, the refrigeration system 1 can switch between operations related to air conditioning and cooling the interior of the showcase without stopping the low-stage compressor 11 and the high-stage compressor 12. In the first switching mechanism 50, the first cooling valve 51, the first heating valve 52, and the outdoor refrigerant return valve 53 may be on-off devices whose opening degrees can be adjusted from fully closed to fully open. The first switching mechanism 50 corresponds to the "discharge refrigerant switching unit" of the present disclosure.

[0032] A second switching mechanism 54 is provided in the piping 40 on the opposite side of the first switching mechanism 50 with the outdoor heat exchanger 15 sandwiched therebetween. That is, the second switching mechanism 54 is connected to the outdoor heat exchanger 15 via the piping 40. The second switching mechanism 54 interconnects the outdoor heat exchanger 15, the indoor heat exchanger 22, the chilled heat exchanger 32, and the gas-liquid separator 16. The second switching mechanism 54 is a mechanism that switches the refrigerant flow to one of a plurality of flow paths that interconnect the outdoor heat exchanger 15, the indoor heat exchanger 22, the chilled heat exchanger 32, and the gas-liquid separator 16.

[0033] The second switching mechanism 54 is formed by annularly connecting the ends of the first to fourth pipes 73, 74, 75, and 76 at connection parts A, B, C, and D. A throttle mechanism 55 is disposed in the first pipe 73. A refrigerant return expansion mechanism 58 that controls the flow rate is disposed in the second pipe 74. A check valve 59 is disposed in the third pipe 75. A check valve 59 is disposed in the fourth pipe 76.

[0034] The throttling mechanism 55 and the refrigerant return expansion mechanism 58 are flow control valves whose opening can be changed from fully closed to fully open. The throttling mechanism 55 can change the pressure of the refrigerant flowing through the first pipe 73 by adjusting its opening. The refrigerant return expansion mechanism 58 can change the pressure of the refrigerant flowing through the second pipe 74 by adjusting its opening. In other words, the throttling mechanism 55 and the refrigerant return expansion mechanism 58 function as a so-called throttle valve. The throttling mechanism 55 corresponds to the "first throttling section" in this disclosure.

[0035] In the third pipe 75, the check valve 59 is arranged so that the refrigerant flows only from the connection part B to the connection part C. In the fourth pipe 76, the check valve 59 is arranged so that the refrigerant flows only from the connection part C to the connection part D.

[0036] A piping 40 in which the outdoor heat exchanger 15 is provided is connected to a connection portion A between the throttle mechanism 55 and the refrigerant return expansion mechanism 58. A connection part B between the refrigerant return expansion mechanism 58 and the check valve 59 provided on the third pipe 75 is connected to a midpoint of the pipe 77 connecting the gas-liquid separator 16 and the chilled heat exchanger 32. In the pipe 77, a chilled-use inlet-side expansion mechanism 31 is provided between the point where the connection part B is connected and the chilled heat exchanger 32.

[0037] A connection part C between the check valve 59 provided in the third pipe 75 and the check valve 59 provided in the fourth pipe 76 is connected to the indoor heat exchanger 22 via a pipe 78. An indoor expansion mechanism 21 of the indoor unit 20 is provided in the pipe 78 between one end connected to the connection part C and the indoor heat exchanger 22. The indoor expansion mechanism 21 is an opening / closing device whose opening degree can be changed from fully closed to fully open. A connection D between the check valve 59 provided in the fourth pipe 76 and the throttle mechanism 55 is connected to the gas-liquid separator 16 via a pipe 69 .

[0038] As described above, the gas-liquid separator 16 is connected to the outdoor heat exchanger 15, the indoor heat exchanger 22, and the cold-set heat exchanger 32 via the second switching mechanism 54. As a result, when the refrigeration system 1 is operating, the refrigerant flows into the gas-liquid separator 16 through the pipe 69 and flows out through the pipe 77. That is, the pipe 69 functions as the inlet-side pipe of the gas-liquid separator 16, and the pipe 77 functions as the outlet-side pipe of the gas-liquid separator 16. The second switching mechanism 54 corresponds to the "flow path switching unit" in this disclosure.

[0039] The pipe 77 allows the liquid refrigerant separated in the gas-liquid separator 16 to flow into the chilled-use heat exchanger 32 via the chilled-use inlet-side expansion mechanism 31. The chilled-use inlet-side expansion mechanism 31 adjusts the pressure of the refrigerant, causing the chilled-use heat exchanger 32 to function as an evaporator. Therefore, the chilled-use heat exchanger 32 can perform cooling regardless of whether the indoor unit 20 cools or heats the target space.

[0040] A first heat exchanger 91 is provided in the piping 69. The first heat exchanger 91 is a heat exchanger that constitutes the humidity control unit 3. The first heat exchanger 91 and the piping 69 in which the first heat exchanger 91 is arranged constitute a first flow path 90A.

[0041] A pipe 68 is provided between the second switching mechanism 54 and the gas-liquid separator 16. One end of the pipe 68 is connected to the connection part A, and the other end is joined with the pipe 69 and connected to the gas-liquid separator 16. A second heat exchanger 92 and a first throttling mechanism 93 are provided in the pipe 68. The pipe 68 is a flow path for flowing the refrigerant from the connection part A to the second heat exchanger 92, and the refrigerant that leaves the second heat exchanger 92 is sent to the gas-liquid separator 16. The first throttling mechanism 93 is located upstream of the second heat exchanger 92 in the pipe 68, and adjusts the pressure of the refrigerant flowing into the second heat exchanger 92. The second heat exchanger 92 is a heat exchanger that constitutes the humidity control unit 3. The second heat exchanger 92, the first throttling mechanism 93, and the pipe 68 constitute a second flow path 90B.

[0042] A second throttling mechanism 94 may be provided in the piping 68. The second throttling mechanism 94 is provided in the piping 68 downstream of the second heat exchanger 92, and adjusts the pressure of the refrigerant flowing from the second heat exchanger 92 to the gas-liquid separator 16. The second throttling mechanism 94 may form a second flow path 90B together with the second heat exchanger 92 and the first throttling mechanism 93. The first throttling mechanism 93 corresponds to the "second throttling section" in this disclosure, and the second throttling mechanism 94 corresponds to the "fourth throttling section" in this disclosure.

[0043] A third throttling mechanism 95 may be provided in the piping 69. The third throttling mechanism 95 is provided downstream of the first heat exchanger 91 in the piping 69, and adjusts the pressure of the refrigerant flowing from the first heat exchanger 91 to the gas-liquid separator 16. The third throttling mechanism 95 may form the first flow path 90A together with the first heat exchanger 91 and the throttling mechanism 55. The third throttling mechanism 95 corresponds to the "third throttling section" in this disclosure.

[0044] The second switching mechanism 54 allows the refrigerant that has left the heat exchanger that functions as a gas cooler, either the outdoor heat exchanger 15 or the indoor heat exchanger 22, to flow to one or more of the pipes 68 and 69. For example, when the indoor unit 20 is performing cooling operation, the refrigerant that has left the outdoor heat exchanger 15 can be made to flow from connection part A through the pipe 68 to the second heat exchanger 92, and can also be made to flow from connection part A through the throttling mechanism 55 and the pipe 69 to the first heat exchanger 91.

[0045] In this case, the first heat exchanger 91 and the second heat exchanger 92 function as evaporators. The throttling mechanism 55 adjusts the evaporation temperature of the first heat exchanger 91 and the flow rate of the refrigerant flowing through the first heat exchanger 91. The first throttling mechanism 93 adjusts the evaporation temperature of the second heat exchanger 92 and the flow rate of the refrigerant flowing through the second heat exchanger 92.

[0046] Although the second throttling mechanism 94 and the third throttling mechanism 95 can be omitted, providing them provides the following advantages. For example, when there is a large difference between the evaporation temperature of the first heat exchanger 91 and the temperature of the refrigerant flowing into the gas-liquid separator 16, it is preferable to provide the second throttling mechanism 94 downstream of the second heat exchanger 92 and the third throttling mechanism 95 downstream of the first heat exchanger 91. In this case, the pressure of the refrigerant evaporated in the first heat exchanger 91 is adjusted by the third throttling mechanism 95 before flowing into the gas-liquid separator 16. Therefore, when the evaporation temperature of the first heat exchanger 91 is higher than the temperature of the refrigerant flowing into the gas-liquid separator 16, the pressure of the refrigerant flowing from the first heat exchanger 91 into the gas-liquid separator 16 can be sufficiently reduced by the third throttling mechanism 95. Similarly, when the refrigeration circuit 2 includes the second throttling mechanism 94, the pressure of the refrigerant evaporated in the second heat exchanger 92 is adjusted by the second throttling mechanism 94 before flowing into the gas-liquid separator 16. Therefore, when the evaporation temperature of the second heat exchanger 92 is higher than the refrigerant temperature of the gas-liquid separator 16, the pressure of the refrigerant flowing from the second heat exchanger 92 into the gas-liquid separator 16 can be sufficiently reduced by the second throttling mechanism 94. This makes it possible to prevent or suppress a decrease in capacity due to high-temperature, high-pressure refrigerant flowing into the gas-liquid separator 16, and suppress operations such as increasing the rotation speeds of the low-stage compressor 11 and the high-stage compressor 12 to compensate for the decrease in capacity. This makes it possible to suppress an increase in the amount of power consumed by the refrigeration system 1.

[0047] Next, the utilization side heat exchanger provided in the refrigeration system 1 will be described. 1, when the indoor unit 20 performs cooling operation, the indoor heat exchanger 22 functions as an evaporator. The evaporation temperature of the indoor heat exchanger 22 during cooling operation is determined by the opening degree of the indoor expansion mechanism 21. In this embodiment, the evaporation temperature of the indoor heat exchanger 22 is determined according to the indoor temperature set in the indoor unit 20. The evaporation temperature range of the indoor heat exchanger 22 is, for example, 3°C to 6°C.

[0048] The chilled-use heat exchanger 32 functions as an evaporator regardless of the operating state of the indoor unit 20. The evaporation temperature of the chilled-use heat exchanger 32 is determined by the opening degree of the chilled-use inlet-side expansion mechanism 31. In this embodiment, the evaporation temperature of the chilled-use heat exchanger 32 is determined according to the internal temperature set in the chilled-use equipment 30.

[0049] The refrigeration equipment 30 of this embodiment can select and set the temperature zone inside the cabinet from among, for example, a refrigeration temperature zone (3°C to 6°C), a temperature zone slightly higher than the refrigeration temperature zone (3°C to 8°C), a partial temperature zone (-3°C to -1°C), and a freezing temperature zone (-20°C to -18°C). Therefore, the evaporation temperature zone of the refrigeration heat exchanger 32 is set lower than the temperature zone inside the cabinet.

[0050] When the refrigeration equipment 30 is set to the refrigeration temperature range, the evaporation temperature range of the refrigeration heat exchanger 32 is, for example, from -5°C to 0°C. When the cooling equipment 30 is set to the partial temperature zone, the evaporation temperature zone of the cooling heat exchanger 32 is, for example, from -12°C to -8°C. When the refrigeration equipment 30 is set to the freezing temperature range, the evaporation temperature range of the refrigeration heat exchanger 32 is, for example, from -40°C to 20°C.

[0051] In this way, two use-side heat exchangers with different evaporation temperature ranges are provided in the refrigeration system 1. Of these two use-side heat exchangers with different evaporation temperature ranges, the indoor heat exchanger 22 is connected to the inlet side of the high-stage compressor 12, and the cold-use heat exchanger 32, which has a lower evaporation temperature range than the indoor heat exchanger 22, is connected to the inlet side of the low-stage compressor 11.

[0052] Next, the gas-liquid separator 16 will be described. The gas-liquid separator 16 is a so-called flash tank that separates the gas-liquid two-phase refrigerant that flows in into the gas-liquid separator 16. When the outdoor heat exchanger 15 functions as a gas cooler, the refrigerant flows from the outdoor heat exchanger 15 into the gas-liquid separator 16 through the second switching mechanism 54. In this case, the refrigerant that flows from the second switching mechanism 54 into the gas-liquid separator 16 is decompressed by the throttling mechanism 55.

[0053] Furthermore, when the indoor heat exchanger 22 functions as a gas cooler, the refrigerant flows from the indoor heat exchanger 22 into the gas-liquid separator 16 via the second switching mechanism 54. In this case, the refrigerant flowing from the indoor heat exchanger 22 into the gas-liquid separator 16 is decompressed by the indoor expansion mechanism 21.

[0054] In this way, the refrigerant flows into the gas-liquid separator 16 after having its pressure adjusted by the throttling mechanism 55 or the indoor expansion mechanism 21 via the second switching mechanism 54. That is, by using the second switching mechanism 54, the refrigeration system 1 can adjust the pressure of the refrigerant flowing into the gas-liquid separator 16 with a simple circuit configuration.

[0055] A gas refrigerant return pipe 60 is connected to the gas-liquid separator 16. The gas refrigerant return pipe 60 is connected to the accumulator 13 via a pipe 71. A gas refrigerant flow rate control valve 61 is connected to the gas refrigerant return pipe 60. The gas refrigerant flow rate control valve 61 is an opening / closing device that can change its opening degree from fully closed to fully open. In the refrigeration system 1, the flow rate of gas refrigerant flowing through the gas refrigerant return pipe 60 is adjusted by the opening degree of the gas refrigerant flow rate control valve 61.

[0056] A portion of the gas refrigerant separated in the gas-liquid separator 16 has its flow rate adjusted by the gas refrigerant flow control valve 61 , is sent to the accumulator 13 , and is returned to the suction side of the high-stage compressor 12 . In this way, in the gas-liquid separator 16, a portion of the gas refrigerant separated in the gas-liquid separator 16 is separated from the liquid refrigerant and flows out of the gas-liquid separator 16, thereby cooling the liquid refrigerant to a saturation temperature corresponding to the pressure of the gas-liquid separator 16. That is, in the refrigeration system 1, the gas-liquid separator 16 functions as a heat exchanger that cools the liquid refrigerant, and it is possible to increase the refrigeration capacity of the refrigeration system 1.

[0057] Furthermore, in the refrigeration system 1, the amount of gas refrigerant returning is adjusted by controlling the aperture of the gas refrigerant flow control valve 61, so a pressure difference can be generated before and after the indoor expansion mechanism 21. That is, a pressure difference in the refrigerant can be generated between the inlet and outlet of the indoor unit 20. This prevents the refrigerant flow from stagnating in the refrigeration system 1, particularly when performing cooling operation. Furthermore, in the indoor heat exchanger 22, where the evaporation temperature of the refrigerant is high, it is possible to control the refrigerant flowing through the indoor heat exchanger 22 at a pressure value obtained by adding a specified pressure value to the pressure value at which the refrigerant evaporates.

[0058] The refrigeration system 1 includes an internal heat exchanger 64. The gas refrigerant return pipe 60 and a pipe 77 pass through the internal heat exchanger 64. In detail, the internal heat exchanger 64 is disposed in the pipe 77 between the gas-liquid separator 16 and connection part B, and is disposed in the gas refrigerant return pipe 60 between the gas refrigerant flow rate control valve 61 and the accumulator 13. The internal heat exchanger 64 is a so-called economizer heat exchanger, and exchanges heat between the liquid refrigerant flowing through the pipe 77 and the gas refrigerant flowing through the gas refrigerant return pipe 60.

[0059] In the internal heat exchanger 64, the liquid refrigerant is cooled by the gas refrigerant, so that the liquid refrigerant is more reliably brought into a supercooled state and the degree of supercooling increases. Therefore, even if the temperature of the liquid refrigerant in the gas-liquid separator 16 does not drop to the saturation temperature, the temperature of the liquid refrigerant discharged from the gas-liquid separator 16 can be lowered to below the saturation temperature. This ensures that the refrigeration system 1 maintains the degree of supercooling of the liquid refrigerant supplied to the evaporator, improving operating efficiency.

[0060] The refrigeration circuit 2 is provided with a connecting pipe 66. The connecting pipe 66 connects the pipe 77 between the internal heat exchanger 64 and connection part B, and the gas refrigerant return pipe 60 between the gas refrigerant flow rate control valve 61 and the internal heat exchanger 64. A portion of the liquid refrigerant that has exchanged heat with the gas refrigerant in the internal heat exchanger 64 flows through the connecting pipe 66. The liquid refrigerant flowing through the connecting pipe 66 is mixed with the gas refrigerant before it exchanges heat with the liquid refrigerant in the internal heat exchanger 64.

[0061] Therefore, in the internal heat exchanger 64, heat is exchanged between the liquid refrigerant and the mixed refrigerant of the liquid refrigerant and the gas refrigerant that has been cooled by heat exchange with the gas refrigerant in the internal heat exchanger 64. This makes it possible to increase the degree of subcooling of the liquid refrigerant in the internal heat exchanger 64, thereby enabling further improvement in operating efficiency.

[0062] A liquid refrigerant flow control valve 65 is provided in the connecting pipe 66. This liquid refrigerant flow control valve 65 is an opening / closing device that can change its opening degree from fully closed to fully open. In the refrigeration system 1, the flow rate of the liquid refrigerant flowing through the connecting pipe 66 is adjusted by the opening degree of the liquid refrigerant flow control valve 65.

[0063] [1-1-2. Humidity control unit configuration] FIG. 3 is a schematic diagram showing the configuration of the humidity control unit 3. As shown in FIG. The humidity control unit 3 has a hollow casing 150, and the internal space of the casing 150 is divided by a partition 151 into an outside air passage 152 and an inside air passage 153.

[0064] Outdoor heat exchanger 15 and blower 18 are arranged in outdoor air duct 152. Outdoor air duct 152 is an air flow path through which air from outside the target space flows. For example, outdoor air is taken in from the outdoors through intake port 154 by operation of blower 18, flows through outdoor air duct 152, and is exhausted to the outdoors through exhaust port 155.

[0065] First heat exchanger 91, second heat exchanger 92, and blower 164 are arranged in internal air duct 153. Internal air duct 153 is an air flow path through which air within the target space, i.e., internal air, flows. Air intake port 156 at one end of internal air duct 153 communicates with, for example, an air intake opening into the target space. By operation of blower 164, the internal air taken in from air intake port 156 flows through internal air duct 153 and is exhausted from exhaust port 157 to the target space.

[0066] 3 illustrates portions of the piping 40, the first flow path 90A, and the second flow path 90B, as well as the various components arranged in the casing 150. Arrows also indicate the flow of refrigerant through the piping 40, the first flow path 90A, and the second flow path 90B when the refrigeration system 1 operates in a cooling and dehumidifying mode. The first flow path 90A and the second flow path 90B constitute a "humidity-controlled refrigerant circuit" of the present disclosure.

[0067] A desiccant rotor 160 is disposed in the casing 150, straddling the outside air duct 152 and the inside air duct 153. The casing 150 is a cylindrical structure that is permeable to allow air to pass through in the axial direction, i.e., the thickness direction. A moisture absorbent such as silica gel or zeolite is held inside the desiccant rotor 160, and the moisture absorbent is in a state where it does not easily move inside the desiccant rotor 160.

[0068] The desiccant rotor 160 is installed so as to be rotatable around the center of the circle that is its cross section as a rotation axis. The desiccant rotor 160 rotates around the rotation axis by a power source (not shown) such as a motor. The rotation axis of the desiccant rotor 160 is located at a position overlapping with the partition 151 or in the vicinity of the partition 151. Therefore, as the desiccant rotor 160 rotates, the moisture absorbent carried by the desiccant rotor 160 moves between the outside air duct 152 and the inside air duct 153.

[0069] 3, arrows indicate the ventilation directions in the outdoor air duct 152 and the indoor air duct 153. The outdoor heat exchanger 15 and the blower 18 are located upstream of the desiccant rotor 160 in the ventilation direction of the outdoor air duct 152. Therefore, in the outdoor air duct 152, the outdoor air that has exchanged heat in the outdoor heat exchanger 15 passes through the desiccant rotor 160. The position of the blower 18 may be upstream or downstream of the outdoor heat exchanger 15, but it is preferable that the blower 18 be located close to the outdoor heat exchanger 15.

[0070] In the ventilation direction of the inside air duct 153, the second heat exchanger 92 is located upstream of the desiccant rotor 160, and the first heat exchanger 91 is located downstream of the desiccant rotor 160. Therefore, in the inside air duct 153, the inside air taken in through the air intake 156 exchanges heat in the second heat exchanger 92, then passes through the desiccant rotor 160, and further exchanges heat in the first heat exchanger 91 before being circulated back into the target space. The position of the blower 164 is not limited, but is preferably near either the first heat exchanger 91 or the second heat exchanger 92. Furthermore, multiple blowers 164 may be installed in the inside air duct 153, and each blower 164 is preferably located near the first heat exchanger 91 or the second heat exchanger 92.

[0071] One of the outside air duct 152 and the inside air duct 153 acts as a moisture absorbing section that causes the desiccant rotor 160 to absorb moisture, and the other functions as a regenerating section that causes the moisture absorbent of the desiccant rotor 160 to release moisture.

[0072] When dehumidifying a target space, the refrigeration system 1 causes the first heat exchanger 91 and the second heat exchanger 92 to function as evaporators, and causes the outdoor heat exchanger 15 to operate as a gas cooler. As a result, in the indoor air duct 153, the indoor air taken in from the air intake 156 is cooled by the second heat exchanger 92 and flows into the desiccant rotor 160. Passing through the second heat exchanger 92 increases the relative humidity of the indoor air, which has the advantage of enabling effective dehumidification.

[0073] In the cooling / dehumidification mode, when the indoor unit 20 cools the target space and the humidity control unit 3 dehumidifies, the temperature of the second heat exchanger 92 is set to a temperature higher than the dew point temperature of the indoor air flowing in through the air intake 156. This prevents drain water from being generated in the second heat exchanger 92. Lowering the temperature of the indoor air by the second heat exchanger 92 has the effect of increasing the relative humidity of the indoor air before it flows into the desiccant rotor 160, allowing the desiccant rotor 160 to efficiently absorb moisture. This allows the air in the target space to be dehumidified to a level where drain water is not generated in the indoor unit 20, and is expected to suppress the growth of microorganisms such as mold due to drain water. Furthermore, this allows the elimination and simplification of ancillary equipment used to drain water, such as piping and drain pans, and the configuration can be simplified, thereby simplifying the air conditioning equipment and reducing costs.

[0074] Meanwhile, in the outdoor air duct 152, the outdoor air taken in through the air intake 154 is heated by the outdoor heat exchanger 15, becomes low-humidity air, and flows into the desiccant rotor 160. The desiccant in the desiccant rotor 160 releases moisture when it comes into contact with the low-humidity outdoor air, and is regenerated.

[0075] Furthermore, in the inside air duct 153, the inside air that has passed through the desiccant rotor 160 is cooled by the first heat exchanger 91. The inside air that passes through the desiccant rotor 160 becomes hotter than before passing through the desiccant rotor 160 due to the fact that the regenerated desiccant rotor 160 is hotter than the second heat exchanger 92 and due to the influence of heat of adsorption generated by moisture absorption. By configuring the inside air to undergo heat exchange in the first heat exchanger 91 and then circulate back into the target space, the inside air that has passed through the desiccant rotor 160 and whose temperature has increased can be returned to the target space after its temperature has been adjusted.

[0076] A dew point temperature measuring device 171 and a dew point temperature measuring device 172 may be installed in the inside air duct 153. The dew point temperature measuring devices 171 and 172 are devices that measure the dew point temperature of the inside air, and are so-called dew point meters.

[0077] The dew-point temperature measuring device 171 is located upstream of the second heat exchanger 92 and the desiccant rotor 160, and measures the dew-point temperature of the inside air taken in through the air intake 156. The dew-point temperature measuring device 172 is located downstream of the desiccant rotor 160 and upstream of the first heat exchanger 91, and measures the dew-point temperature of the inside air that passes through the desiccant rotor 160 and flows into the dew-point temperature measuring device 171. The dew-point temperature measuring device 171 corresponds to the "second dew-point temperature measuring device" in this disclosure, and the dew-point temperature measuring device 172 corresponds to the "first dew-point temperature measuring device" in this disclosure.

[0078] The refrigeration system 1 uses the measurement results of the dew point temperature measuring device 171, for example, to measure the humidity in the target space and to control the second heat exchanger 92 to a temperature higher than the dew point temperature of the indoor air. The refrigeration system 1 uses the measurement results of the dew point temperature measuring device 172, for example, to measure the temperature and humidity of the indoor air humidified or dehumidified by the desiccant rotor 160.

[0079] There is no limitation on the distance between the outdoor heat exchanger 15 and the desiccant rotor 160. For example, the outdoor heat exchanger 15 may be disposed outside the casing 150. In this configuration, the outside air that has passed through the outdoor heat exchanger 15 is caused to flow into the outside air passage 152 through a duct and pass through the desiccant rotor 160.

[0080] Similarly, the first heat exchanger 91 and the second heat exchanger 92 may be disposed outside the casing 150. For example, a configuration may be adopted in which the internal air that has passed through the second heat exchanger 92 flows into the internal air passage 153 through a duct connected to the casing 150, passes through the desiccant rotor 160, and is sent to the first heat exchanger 91 through the duct.

[0081] [1-1-3. Humidity control unit function] Figure 4 is a psychrometric chart (hygrometer, hx chart) showing the state of the air in the humidity control unit. The vertical axis of Figure 4 represents absolute humidity, and the horizontal axis represents dry-bulb humidity. The dashed curve H in Figure 4 represents 100% relative humidity.

[0082] Plots D1, D2, D3, and D4 show the dry-bulb temperature and absolute humidity of the air flowing through the indoor air duct 153. Plot D1 shows the state of air taken in through the air intake 156 before passing through the second heat exchanger 92. This air is cooled by passing through the second heat exchanger 92 and reaches the state shown in plot D2. For example, air with a dry-bulb temperature of 27.0°C, a relative humidity of 70%, and an absolute humidity of 0.0157 kg / kg DA in plot D1 experiences a decrease in dry-bulb temperature as it passes through the second heat exchanger 92, resulting in plot D2 (dry-bulb temperature of 22.8°C, a relative humidity of 90%, and an absolute humidity of 0.0157 kg / kg DA). The change from plot D1 to plot D2 is primarily a change in temperature, so the absolute humidity remains almost unchanged. Furthermore, the relative humidity increases as the temperature decreases.

[0083] When the air that has passed through the second heat exchanger 92 passes through the desiccant rotor 160, moisture is adsorbed and the temperature rises, resulting in the state shown by plot D3 (for example, dry-bulb temperature 39.8°C, relative humidity 19.6%, absolute humidity 0.0089 kg / kg DA). When the air passes through the desiccant rotor 160, moisture is removed by the dehumidifying agent, the absolute humidity decreases, and the dry-bulb temperature rises due to the influence of the heat of adsorption and the temperature of the desiccant rotor 160.

[0084] The air that has passed through the desiccant rotor 160 is cooled by passing through the first heat exchanger 91, and reaches the state shown by plot D4 (for example, dry-bulb temperature 27.0°C, relative humidity 40%, absolute humidity 0.0089 kg / kg DA). While the temperature of the air decreases by passing through the first heat exchanger 91, the absolute humidity remains almost unchanged, and the relative humidity increases as the temperature decreases. The dry-bulb temperature of plot D4 is close to that of plot D1, and the absolute humidity is significantly reduced. In this way, the air from the target space that has flowed into the indoor air duct 153 does not change significantly in temperature and is circulated back into the target space in a dehumidified state.

[0085] Plots R11, R12, and R13 show the dry-bulb temperature and absolute humidity of air flowing through outdoor air duct 152. Plot R11 shows the state of air taken in through intake port 154 before passing through outdoor heat exchanger 15. This air is heated as it passes through outdoor heat exchanger 15, and reaches the state shown by plot R12. For example, air with a dry-bulb temperature of 30°C, a relative humidity of 80%, and an absolute humidity of 0.0216 kg / kg DA in plot R11 increases in dry-bulb temperature as it passes through outdoor heat exchanger 15, and reaches the state shown by plot R12 (dry-bulb temperature 80.0°C, relative humidity 7.1%, absolute humidity 0.0216 kg / kg DA). The change from plot R11 to plot R12 is a temperature change, so the absolute humidity remains almost unchanged, and the relative humidity decreases as the temperature increases.

[0086] When the air that has passed through the outdoor heat exchanger 15 passes through the desiccant rotor 160, it removes moisture from the desiccant in the desiccant rotor 160, resulting in the state shown by plot R13 (e.g., dry-bulb temperature 63.0°C, relative humidity 19.4%, absolute humidity 0.0284 kg / kg DA). As the moisture is removed from the desiccant, the absolute humidity increases, while the dry-bulb temperature decreases. In this way, the air from the target space that has flowed into the outdoor air duct 152 passes through the outdoor heat exchanger 15, resulting in a low relative humidity, which removes moisture from the desiccant rotor 160 and regenerates the desiccant.

[0087] [1-1-4. Another example of a refrigeration circuit configuration] FIG. 5 is a diagram showing a refrigeration circuit 2D as another example of the configuration of the refrigeration circuit 2. In FIG. The refrigeration circuit 2D includes an outdoor unit 10, an indoor unit 20, and a cooling equipment 30, and constitutes a refrigeration system 1D that performs air conditioning of a target space and cooling of the cooling equipment 30.

[0088] The refrigeration system 1D has the same configuration as the refrigeration system 1 except for the humidity control unit 3. Specifically, the first heat exchanger 91, the second heat exchanger 92, the first throttling mechanism 93, the second throttling mechanism 94, and the third throttling mechanism 95 are not arranged in the piping 68 and the piping 69 of the refrigeration circuit 2D.

[0089] When a humidity control unit 3 is added to the refrigeration system 1D, pipe connection ports 181, 182, and 183 may be provided in the refrigeration circuit 2D. The pipe connection ports 181 and 182 are configured to allow a new refrigerant pipe to be connected between the pipe connection ports 181 and 182, and to block the pipe 68 connecting the pipe connection ports 181 and 182 in the refrigeration circuit 2D. The pipe connection ports 181 and 182 are, for example, three-way valves. By connecting a new refrigerant pipe having a second heat exchanger 92, a first throttling mechanism 93, and a second throttling mechanism 94 between the pipe connection ports 181 and 182, a first flow path 90A can be added to the refrigeration circuit 2D.

[0090] The piping connection port 183 allows a new refrigerant piping to be connected between the connection portion A and the piping connection port 181 or the piping connection port 182. The piping connection port 183 is a valve, such as a three-way valve, that allows a new refrigerant piping to be connected to the connection portion A of the second switching mechanism 54. By connecting a new refrigerant piping having the first heat exchanger 91 and the third throttling mechanism 95 between the piping connection port 183 and the piping connection port 181 or the piping connection port 182, a second flow path 90B can be added to the refrigeration circuit 2D. The pipe connection ports 181, 182, and 183 correspond to the "connection parts" of the present disclosure.

[0091] In this way, the humidity control unit 3 can be installed as an add-on to the refrigeration circuit 2D that includes the outdoor unit 10, the indoor unit 20, and the cooling equipment 30, and humidity control can be performed in the target space.

[0092] [1-1-5. Configuration related to refrigeration system control] FIG. 6 is a block diagram of the refrigeration system 1. The block diagram in Fig. 6 shows the connection relationships in terms of control for the components that make up the refrigeration system 1, and illustrates at least a portion of the configuration of the refrigeration system 1. The refrigeration system 1 may include configurations that are not shown in Fig. 6. Furthermore, there is no intention to restrict the refrigeration system 1 from omitting some of the configurations shown in Fig. 6.

[0093] The refrigeration system 1 is provided with a plurality of refrigerant pressure sensors 80. The refrigerant pressure sensors 80 are provided at predetermined locations in the refrigeration circuit 2, which includes the outdoor unit 10, the indoor unit 20, and the cooling equipment 30. The refrigerant pressure sensors 80 detect the pressure of the refrigerant flowing through those locations.

[0094] 1 and 2, the refrigerant pressure sensor 80 may be provided in the pipe 77 between the gas-liquid separator 16 and the internal heat exchanger 64. Alternatively, the refrigerant pressure sensor 80 may be provided in the gas refrigerant return pipe 60 between the gas refrigerant flow control valve 61 and the accumulator 13. Alternatively, the refrigerant pressure sensor 80 may be provided in the pipe 71, between the indoor heat exchanger 22 and a connection point between the pipe 71 and the first heating pipe 41. Alternatively, the refrigerant pressure sensor 80 may be provided in the pipe 72, between the cooling outlet pressure adjustment mechanism 33 and the suction side of the low-stage compressor 11. Alternatively, the refrigerant pressure sensor 80 may be provided in a refrigerant pipe connecting the discharge side of the high-stage compressor 12 and the oil separator 14.

[0095] The refrigerant pressure sensor 80 may be provided in the first flow path 90A and the second flow path 90B. For example, as shown in FIGS. 1 and 2, the refrigerant pressure sensor 80 may be provided in the pipe 68 between the second heat exchanger 92 and the gas-liquid separator 16, or the refrigerant pressure sensor 80 may be provided in the pipe 69 between the first heat exchanger 91 and the gas-liquid separator 16. For example, as shown in FIGS. 1 and 2, the refrigerant pressure sensor 80 may be provided in the first flow path 90A downstream of the first heat exchanger 91 and between the first heat exchanger 91 and the third throttling mechanism 95. This refrigerant pressure sensor 80 corresponds to the "first pressure measuring device" in the present disclosure. Alternatively, for example, the refrigerant pressure sensor 80 may be provided in the second flow path 90B downstream of the second heat exchanger 92. This refrigerant pressure sensor 80 corresponds to the "second pressure measuring device" in the present disclosure.

[0096] The refrigeration system 1 may be provided with a refrigerant temperature sensor 82 that detects the temperature of the refrigerant. The refrigerant temperature sensor 82 is provided, for example, at a plurality of locations in the refrigeration circuit 2 including the outdoor unit 10, the indoor unit 20, and the cooling equipment 30. Also, for example, the refrigerant temperature sensor 82 is provided in a refrigerant pipe located on the suction side and a refrigerant pipe located on the discharge side of each of the high-stage compressors 12. Also, the refrigerant temperature sensor 82 is provided in a pipe 72 located on the suction side of the low-stage compressor 11, between the cooling-use outlet-side pressure adjustment mechanism 33 and the suction side of the low-stage compressor 11. Also, for example, the refrigerant temperature sensor 82 is provided in each of the refrigerant pipes connected to the inlet side and the outlet side of each of the indoor heat exchanger 22 and the cooling-use heat exchanger 32.

[0097] The refrigeration system 1 includes a space temperature sensor 27 and a space humidity sensor 29. The space temperature sensor 27 is placed in the space to be conditioned by the indoor unit 20, i.e., the target space, and detects the temperature of the target space. The space humidity sensor 29 detects the humidity in the target space. The space temperature sensor 27 and the space humidity sensor 29 are mounted, for example, on the indoor unit 20. The refrigeration system 1 includes an internal temperature sensor 37. The internal temperature sensor 37 is placed inside a refrigerated showcase or freezer showcase included in the refrigeration equipment 30 and detects the internal temperature.

[0098] The outdoor unit 10, the indoor unit 20, and the cooling equipment 30 are provided with fans 18, 28, and 38, respectively. The fans 18, 28, and 38 send air through the outdoor heat exchanger 15, the indoor heat exchanger 22, and the cooling heat exchanger 32, respectively, to promote heat exchange between the air and the refrigerant flowing through the outdoor heat exchanger 15, the indoor heat exchanger 22, and the cooling heat exchanger 32.

[0099] The outdoor unit 10 includes an outdoor unit communication unit 106 that communicates with the indoor unit 20 via control wiring (hereinafter referred to as control wiring). The outdoor unit communication unit 106 is configured with communication hardware such as connectors and communication circuits that comply with a predetermined communication standard.

[0100] The outdoor unit 10 is equipped with a control device 100. An outdoor unit I / F (interface) 105 is equipped with communication hardware such as connectors and communication circuits that comply with a predetermined communication standard. The outdoor unit I / F 105 is connected to each part of the outdoor unit 10 via control wiring. For example, the outdoor unit I / F 105 is connected to the low-stage compressor 11, the high-stage compressor 12, the blower 18, the on-off valve 23, the refrigerant pressure sensor 80, the refrigerant temperature sensor 82, the oil level sensor 83, and the outdoor unit communication unit 106, and communicates with each of these parts. In addition, the outdoor unit I / F 105 is connected to the first cooling valve 51, the first heating valve 52, the outdoor refrigerant return valve 53, the throttling mechanism 55, the refrigerant return expansion mechanism 58, the on-off valve 23, the gas refrigerant flow control valve 61, the liquid refrigerant flow control valve 65, the first throttling mechanism 93, the second throttling mechanism 94, and the third throttling mechanism 95, and communicates with each of these parts.

[0101] In addition, the outdoor unit I / F 105 is connected to the indoor unit I / F 115, the cooling equipment I / F 125, the dew point temperature measuring devices 171 and 172 of the humidity control unit 3, and the blower 164, and executes communication with each of these parts.

[0102] The control device 100 includes a control unit 101 and a storage unit 103. The control unit 101 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) that operates based on a program stored in advance in the storage unit 103. The control unit 101 may be configured with a single processor or multiple processors, and may use a control circuit such as a DSP (Digital Signal Processor), an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programming Gate Array). The control unit 101 receives various signals from each part of the refrigeration system 1 via an outdoor unit I / F 105 and outputs signals, etc. to each part of the refrigeration system 1 to control them.

[0103] The control unit 101 functions as an operation control unit 101a and a determination unit 101b by reading and executing a computer program stored in the memory unit 103. The operation control unit 101a controls the operation of the refrigeration system 1. For example, the operation control unit 101a transmits control signals instructing each unit connected to the outdoor unit I / F 105 to operate, and receives control signals indicating the operating state and measurement results. The determination unit 101b compares the measurement results and measurements of the space temperature sensor 27, the space humidity sensor 29, the refrigerant pressure sensor 80, the refrigerant temperature sensor 82, the dew point temperature measuring devices 171 and 172, etc. with reference temperatures and reference pressure values ​​included in the setting data 103a. The operation control unit 101a controls each unit of the refrigeration system 1 based on the determination of the determination unit 101b.

[0104] The storage unit 103 includes a storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), or a fixed disk device. The storage unit 103 stores computer programs, databases, tables, and the like used for various operations of the refrigeration system 1. The storage unit 103 includes a volatile storage area and may constitute a work area for the control unit 101. The storage unit 103 stores setting data 103a including various data used for operational control of the refrigeration system 1.

[0105] The outdoor unit I / F 105 includes communication hardware such as a communication interface circuit and a connector that allows the outdoor unit 10 to communicate with each device via a cable or the like in accordance with a predetermined communication protocol. The control device 100 includes an operation panel 132. The operation panel 132 includes controls such as buttons and switches, or a touch sensor that detects operations, and accepts operations by an operator. The control device 100 includes a display panel 134. The display panel 134 displays various information related to the operation of the refrigeration system 1 according to the control of the control unit 101.

[0106] The indoor unit 20 is equipped with an indoor unit control device 110 and an indoor unit I / F 115. The indoor unit control device 110 is equipped with an indoor unit control section 111 and an indoor unit memory section 113. The indoor unit control section 111 is equipped with a processor similar to that of the control section 101, and controls various devices such as the blower 28 mounted in the indoor unit 20. The indoor unit memory section 113, like the memory section 103, has storage devices such as RAM and ROM, and stores computer programs and the like used for various operations of the indoor unit 20. The indoor unit I / F 115 is equipped with communication hardware such as a communication interface circuit and connectors that enable the indoor unit 20 to communicate with each device, and sends data received from each device to the indoor unit control device 110, and also sends data received from the indoor unit control device 110 to each device.

[0107] The refrigeration equipment 30 includes a refrigeration equipment control device 120 and a refrigeration equipment I / F 125. The refrigeration equipment control device 120 includes a refrigeration equipment control unit 121 and a refrigeration equipment storage unit 123. The refrigeration equipment control unit 121 includes a processor similar to that of the control unit 101, and controls various devices such as the blower 38 installed in the refrigeration equipment 30. The refrigeration equipment storage unit 123, like the storage unit 103, includes storage devices such as RAM and ROM, and stores computer programs and the like used for various operations of the refrigeration equipment 30. The refrigeration equipment I / F 125 includes communication hardware such as a communication interface circuit and connectors that allow the refrigeration equipment 30 to communicate with each device, and sends data received from each device to the refrigeration equipment control device 120 and transmits data received from the refrigeration equipment control device 120 to each device.

[0108] The functions of the operation control unit 101a and the determination unit 101b may be configured to be executed by the indoor unit control unit 111 or the cooling equipment control unit 121, or may be configured to be executed by other devices.

[0109] [1-2. Refrigeration system operation] Next, the operation of this embodiment will be described.

[0110] [1-2-1. Cooling and dehumidification mode] The operation of the refrigeration system 1 in the cooling and dehumidifying mode will be described with reference to FIG. In the cooling and dehumidifying mode, the control device 100 controls the outdoor heat exchanger 15 to operate as a gas cooler or a radiator, and the indoor heat exchanger 22 and the cooling heat exchanger 32 to operate as evaporators.

[0111] The control device 100 opens the first cooling valve 51 and closes the first heating valve 52 and the outdoor refrigerant return valve 53 in the first switching mechanism 50. The control device 100 opens the throttling mechanism 55 and closes the refrigerant return expansion mechanism 58 in the second switching mechanism 54.

[0112] When each of the low-stage compressor 11 and the high-stage compressor 12 operates, the refrigerant compressed by the low-stage compressor 11 is sent to each of the high-stage compressors 12, where it is further compressed and discharged toward the oil separator 14.

[0113] The refrigerant that has flowed into the oil separator 14 is sent from the oil separator 14 through the first cooling valve 51 to the outdoor heat exchanger 15, where it exchanges heat with outside air.

[0114] The refrigerant that has undergone heat exchange in the outdoor heat exchanger 15 branches at a connection A of the second switching mechanism 54. That is, a portion of the refrigerant that has reached the connection A from the outdoor heat exchanger 15 flows from the connection A through the pipe 68 into the second flow path 90B. The refrigerant is decompressed by the first throttling mechanism 93 and flows into the second heat exchanger 92. Here, the second heat exchanger 92 operates as an evaporator, and exchanges heat between the refrigerant and the indoor air that has flowed in from the intake port 156 in the indoor air passage 153, thereby cooling the indoor air. That is, the second heat exchanger 92 cools the indoor air flowing from the target space toward the desiccant rotor 160 upstream of the desiccant rotor 160. The refrigerant that has undergone heat exchange in the second heat exchanger 92 has its pressure adjusted by the third throttling mechanism 95 and flows into the gas-liquid separator 16.

[0115] As described above, it is preferable that the control device 100 controls the opening degree of the first throttling mechanism 93 so that the evaporation temperature in the second heat exchanger 92 is higher than the dew-point temperature measured by the dew-point temperature measuring device 171. The control device 100 adjusts the opening degree of the first throttling mechanism 93 based on, for example, the measurement result of the dew-point temperature measuring device 171, the refrigerant temperature detected by the refrigerant temperature sensor 82, the refrigerant pressure detected by the refrigerant pressure sensor 80 downstream of the second heat exchanger 92, etc.

[0116] The remainder of the refrigerant that reaches connection portion A from outdoor heat exchanger 15 flows from connection portion A to pipe 69 via throttling mechanism 55. This refrigerant is depressurized by throttling mechanism 55, and first heat exchanger 91 functions as an evaporator. As a result, the inside air that has passed through desiccant rotor 160 in inside air duct 153 is cooled by first heat exchanger 91. The refrigerant that has exchanged heat in first heat exchanger 91 flows into gas-liquid separator 16 after its pressure has been adjusted by third throttling mechanism 95.

[0117] The refrigeration system 1 may be configured without the second throttling mechanism 94 and the refrigerant pressure sensor 80 between the second heat exchanger 92 and the second throttling mechanism 94. In this configuration with the refrigerant pressure sensor 80 and the second throttling mechanism 94, the pressure of the refrigerant that has exchanged heat in the second heat exchanger 92 is detected by the refrigerant pressure sensor 80, and the pressure of the refrigerant flowing into the gas-liquid separator 16 can be adjusted by the second throttling mechanism 94 based on the detected pressure. This expands the adjustment range of the throttling amount of the first throttling mechanism 93. Therefore, for example, as described above, it is possible to control the evaporation temperature of the second heat exchanger 92, allowing effective dehumidification by the desiccant rotor 160.

[0118] The refrigeration system 1 may be configured without the third throttling mechanism 95 and the refrigerant pressure sensor 80 between the first heat exchanger 91 and the third throttling mechanism 95. In this configuration with the refrigerant pressure sensor 80 and the third throttling mechanism 95, the pressure of the refrigerant that has exchanged heat in the first heat exchanger 91 is detected by the refrigerant pressure sensor 80, and the pressure of the refrigerant flowing into the gas-liquid separator 16 can be adjusted by the third throttling mechanism 95 based on the detected pressure. This expands the adjustment range of the throttling amount in the first throttling mechanism 93.

[0119] The liquid refrigerant separated in the gas-liquid separator 16 passes through piping 77, undergoes heat exchange with the gas refrigerant in the internal heat exchanger 64, and then reaches connection part B of the second switching mechanism 54. The refrigerant branches at connection part B. One of the refrigerants branched at connection part B passes through piping 78 and is sent to the indoor heat exchanger 22 via the check valve 59 provided in piping 75 and the indoor expansion mechanism 21 of the indoor unit 20. The indoor heat exchanger 22 functions as an evaporator, and the refrigerant exchanges heat with the indoor air in the indoor heat exchanger 22 to cool the indoor air. The refrigerant that has exchanged heat with the indoor air passes through the pipe 71 and the on-off valve 23, and is returned to the suction side of each of the high-stage compressors 12 via the on-off valve 23 and the accumulator 13.

[0120] The other refrigerant branched at connection point B is sent to refrigeration heat exchanger 32 via refrigeration inlet expansion mechanism 31 of refrigeration equipment 30, where it undergoes heat exchange and cools refrigeration equipment 30. The refrigerant that has undergone heat exchange in refrigeration heat exchanger 32 is returned to low-stage compressor 11 via refrigeration outlet pressure adjustment mechanism 33.

[0121] [1-2-2. Cooling mode] In the cooling mode, the refrigeration system 1 performs cooling of the target space by the indoor unit 20 and cooling by the cooling equipment 30, but does not perform humidity control by the humidity control unit 3.

[0122] The flow of refrigerant in the cooling mode is the same as in the cooling and dehumidifying mode, except for the first flow path 90A and the second flow path 90B. In the cooling mode, the control device 100 fully closes the first throttling mechanism 93 to stop the flow of refrigerant to the second heat exchanger 92. Here, in a configuration where the second throttling mechanism 94 is provided, the control device 100 fully opens the second throttling mechanism 94 to prevent liquid sealing.

[0123] By fully closing the first throttling mechanism 93, the refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows from the connection part A to the throttling mechanism 55. The control device 100 adjusts the opening degree of the throttling mechanism 55 so that the pressure of the refrigerant flowing into the gas-liquid separator 16 is within an appropriate range. Here, in a configuration where the third throttling mechanism 95 is provided, the control device 100 fully opens the third throttling mechanism 95. The control device 100 also stops the blower 164 so that the inside air is not ventilated in the inside air duct 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15, which operates as a gas cooler.

[0124] By the above control, in the cooling mode, the humidity control unit 3 is stopped, and the indoor unit 20 performs cooling and the cooling equipment 30 is cooled.

[0125] [1-2-3. Space dehumidification mode] The refrigeration system 1 can also execute a space dehumidification mode in which the indoor unit 20 does not perform air conditioning of the target space, but the cooling equipment 30 operates and the humidity adjustment unit 3 performs dehumidification. In the space dehumidification mode, the cooling heat exchanger 32 functions as an evaporator, and the outdoor heat exchanger 15 functions as a gas cooler. The states of the opening and closing devices in the space dehumidification mode are the same as those in the cooling and dehumidification mode, except that the indoor expansion mechanism 21 is fully closed.

[0126] In the space dehumidification mode, the indoor expansion mechanism 21 is fully closed, and therefore the refrigerant does not flow to the indoor heat exchanger 22. In addition, the blower 28 provided in association with the indoor heat exchanger 22 does not operate. In this case, the outdoor heat exchanger 15, the first heat exchanger 91, and the second heat exchanger 92 operate, and the humidity control unit 3 dehumidifies the target space, as in the cooling dehumidification mode.

[0127] [1-2-4. Heating and dehumidification mode] The operation of the refrigeration system 1 in the heating and dehumidifying mode will be described with reference to FIG. When the indoor unit 20 heats the target space, the indoor heat exchanger 22 operates as a gas cooler or a radiator. The cooling heat exchanger 32 operates as an evaporator regardless of whether the indoor unit 20 is cooling or heating. The outdoor heat exchanger 15 operates as either an evaporator or a gas cooler depending on the balance between the amount of heat required by the indoor unit 20 and the amount of heat obtained by the cooling heat exchanger 32 as an evaporator.

[0128] Specifically, when the amount of heat obtained by the chilled-use heat exchanger 32 is equal to or greater than the amount of heat required by the indoor unit 20 for heating, the outdoor heat exchanger 15 functions as a gas cooler. This state is called an excess heat state. In contrast, when the amount of heat obtained by the chilled-use heat exchanger 32 as an evaporator is less than the amount of heat required by the indoor unit 20 for heating, the outdoor heat exchanger 15 functions as an evaporator. This state is called a heat shortage state. In a heat shortage state, the amount of heat required by the indoor unit 20 is obtained from both the outdoor heat exchanger 15 and the chilled-use heat exchanger 32, making it possible to heat the target space.

[0129] When dehumidification is performed by the humidity control unit 3, the outdoor heat exchanger 15 is operated as a gas cooler to regenerate the desiccant in the desiccant rotor 160 in the outdoor air duct 152. Therefore, the refrigeration system 1 executes the heating and dehumidification mode when the amount of heat is excessive. Note that the refrigeration system 1 can execute the heating mode when the amount of heat is insufficient.

[0130] 2, in the heating / dehumidifying mode, the control device 100 opens the first cooling valve 51 and the first heating valve 52 in the first switching mechanism 50 and closes the outdoor refrigerant return valve 53. The control device 100 closes the refrigerant return expansion mechanism 58 in the second switching mechanism 54.

[0131] When each of the low-stage compressor 11 and the high-stage compressor 12 operates, the refrigerant compressed by the low-stage compressor 11 is sent to each of the high-stage compressors 12, where it is further compressed and discharged toward the oil separator 14. The refrigerant that flows into the oil separator 14 branches into a path that passes from the oil separator 14 through the first heating valve 52 to the indoor heat exchanger 22, and a path that passes from the oil separator 14 through the first cooling valve 51 to the outdoor heat exchanger 15.

[0132] The refrigerant sent to the indoor heat exchanger 22 exchanges heat with the indoor air in the indoor heat exchanger 22, heating the indoor air. The refrigerant that has exchanged heat in the indoor heat exchanger 22 passes through the indoor expansion mechanism 21, reaches connection C of the second switching mechanism 54, passes through a check valve 59 provided in the pipe 76, and flows from connection D to the pipe 69. The refrigerant is decompressed in the indoor expansion mechanism 21, and the first heat exchanger 91 functions as an evaporator. As a result, the indoor air that has passed through the desiccant rotor 160 in the indoor air duct 153 is cooled by the first heat exchanger 91. The refrigerant that has exchanged heat in the first heat exchanger 91 flows into the gas-liquid separator 16 after its pressure has been adjusted by the third throttling mechanism 95.

[0133] The refrigerant that flows through the first cooling valve 51 to the outdoor heat exchanger 15 undergoes heat exchange in the outdoor heat exchanger 15 and regenerates the desiccant in the desiccant rotor 160 in the outdoor air duct 152. After heat exchange in the outdoor heat exchanger 15, the refrigerant branches at a connection A of the second switching mechanism 54 in the same manner as in the cooling / dehumidifying mode. That is, a portion of the refrigerant that reaches the connection A from the outdoor heat exchanger 15 flows from the connection A through the piping 68 to the second flow path 90B. The pressure of this refrigerant is reduced by the first throttling mechanism 93 and flows into the second heat exchanger 92. Here, the second heat exchanger 92 operates as an evaporator, exchanging heat between the refrigerant and the indoor air that flows in from the intake port 156 in the indoor air duct 153, thereby cooling the indoor air. That is, the second heat exchanger 92 cools the inside air flowing from the target space toward the desiccant rotor 160 upstream of the desiccant rotor 160. The refrigerant that has exchanged heat in the second heat exchanger 92 has its pressure adjusted by the third throttling mechanism 95 and flows into the gas-liquid separator 16.

[0134] In the heating / dehumidifying mode, the effects achieved by providing the refrigerant pressure sensor 80 and the second throttling mechanism 94 in the first flow path 90A, and by providing the refrigerant pressure sensor 80 and the third throttling mechanism 95 in the second flow path 90B, are the same as those in the cooling / dehumidifying mode. In the heating and dehumidifying mode, the outdoor heat exchanger 15, the first heat exchanger 91, and the second heat exchanger 92 in the humidity control unit 3 operate in the same manner as in the cooling and dehumidifying mode.

[0135] In the gas-liquid separator 16, the refrigerant flowing into the gas-liquid separator 16 from the first heat exchanger 91 and the refrigerant flowing into the gas-liquid separator 16 from the second heat exchanger 92 are separated into liquid and gas. The separated refrigerant passes through the pipe 77 to reach the connection part B of the second switching mechanism 54, and is sent to the chilled-set heat exchanger 32 via the chilled-set inlet-side expansion mechanism 31. This refrigerant undergoes heat exchange in the chilled-set heat exchanger 32, and cools the chilled-set equipment 30.

[0136] The refrigerant that has exchanged heat in the chiller heat exchanger 32 passes through the pipe 72 and is returned to the suction side of the low-stage compressor 11 via the chiller outlet pressure adjustment mechanism 33 .

[0137] [1-2-5. Heating mode] In the heating mode, the refrigeration system 1 performs heating of the target space by the indoor unit 20 and cooling by the cooling equipment 30, but does not perform humidity control by the humidity control unit 3. When the heating mode is performed in a state where the amount of heat is excessive, the flow of the refrigerant is the same as in the heating and dehumidifying mode, except for the first flow path 90A and the second flow path 90B.

[0138] In the heating mode, the control device 100 fully closes the first throttling mechanism 93 to stop the flow of refrigerant to the second heat exchanger 92. Here, in a configuration where the second throttling mechanism 94 is provided, the control device 100 fully opens the second throttling mechanism 94 to prevent liquid sealing. By fully closing the first throttling mechanism 93, the refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows from the connection part A to the throttling mechanism 55. The control device 100 adjusts the opening degree of the throttling mechanism 55 so that the pressure of the refrigerant flowing into the gas-liquid separator 16 is within an appropriate range. Here, in a configuration where the third throttling mechanism 95 is provided, the control device 100 fully opens the third throttling mechanism 95.

[0139] Furthermore, the refrigerant that has exchanged heat in the indoor heat exchanger 22 flows from the connection part C through the check valve 59 to the pipe 69, as in the heating and dehumidifying mode. The control device 100 adjusts the aperture of the indoor expansion mechanism 21 so that the pressure of the refrigerant flowing into the gas-liquid separator 16 is within an appropriate range.

[0140] The control device 100 stops the blower 164 and does not allow the inside air to be ventilated into the inside air duct 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15 that operates as a gas cooler.

[0141] By the above control, when the heating mode is executed in a state where the amount of heat is excessive, the refrigeration system 1 can stop the humidity control unit 3 and perform heating by the indoor unit 20 and cooling by the cooling equipment 30.

[0142] When the heating mode is executed in a state where the amount of heat is insufficient, the outdoor heat exchanger 15 functions as an evaporator. The control device 100 closes the first cooling valve 51 in the first switching mechanism 50 and opens the first heating valve 52 and the outdoor refrigerant return valve 53. The control device 100 closes the throttling mechanism 55 in the second switching mechanism 54.

[0143] When each of the low-stage compressor 11 and the high-stage compressor 12 operates, the refrigerant compressed by the low-stage compressor 11 is sent to each of the high-stage compressors 12, where it is further compressed and discharged toward the oil separator 14. The refrigerant that has flowed into the oil separator 14 passes from the oil separator 14 through the first heating valve 52 and is sent to the indoor heat exchanger 22.

[0144] The refrigerant sent to the indoor heat exchanger 22 exchanges heat with the indoor air in the indoor heat exchanger 22, heating the indoor air. The refrigerant that has exchanged heat in the indoor heat exchanger 22 passes through the indoor expansion mechanism 21, reaches the connection part C of the second switching mechanism 54, passes through the check valve 59 provided in the pipe 76, and flows from the connection part D to the pipe 69.

[0145] The refrigerant that has flowed into the piping 69 passes through the first heat exchanger 91 and the third throttling mechanism 95 and flows into the gas-liquid separator 16. Here, if the third throttling mechanism 95 is provided in the piping 69, the control device 100 adjusts the pressure of the refrigerant flowing into the gas-liquid separator 16 by controlling the opening degree of the third throttling mechanism 95 based on the pressure of the refrigerant passing through the first heat exchanger 91 and the pressure in the gas-liquid separator 16.

[0146] In the gas-liquid separator 16, the refrigerant flowing into the gas-liquid separator 16 from the first heat exchanger 91 is separated into a liquid and a gas. The separated refrigerant passes through the pipe 77 to reach the connection part B of the second switching mechanism 54 and branches at the connection part B. That is, a part of the refrigerant that has reached the connection part B is sent from the connection part B via the chiller-use inlet-side expansion mechanism 31 to the chiller-use heat exchanger 32, where it undergoes heat exchange and cools the chiller-use equipment 30.

[0147] The remainder of the refrigerant that has reached connection part B passes from connection part B through refrigerant return expansion mechanism 58, is depressurized by refrigerant return expansion mechanism 58, and reaches connection part A. The control device 100 fully closes the first throttling mechanism 93. As a result, the refrigerant that has reached connection part A does not flow to the second heat exchanger 92, but flows to the outdoor heat exchanger 15. Since the refrigerant that has flowed to the outdoor heat exchanger 15 has been depressurized by the refrigerant return expansion mechanism 58, it evaporates in the outdoor heat exchanger 15 and exchanges heat with the outside air. In a configuration in which the second throttling mechanism 94 is provided in the piping 68, the control device 100 fully opens the second throttling mechanism 94 to prevent liquid sealing.

[0148] The refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows through the outdoor refrigerant return valve 53 of the first switching mechanism 50 to the first outdoor return piping 42, and is returned to the suction side of the low-stage compressor 11 through piping 72.

[0149] Furthermore, similar to the heating mode with excess heat, the control device 100 stops the blower 164 and does not ventilate the inside air into the inside air duct 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15 that operates as a gas cooler.

[0150] By the above control, even when there is a heat shortage, the refrigeration system 1 can execute the heating mode, stop the humidity control unit 3, and perform heating by the indoor unit 20 and cooling by the cooling equipment 30.

[0151] In the refrigeration system 1 of the present disclosure, during heating operation, the indoor heat exchanger 22 functions as a gas cooler or a radiator, and the outdoor heat exchanger 15 is not used. That is, the refrigeration system 1 can operate without using the outdoor heat exchanger 15 by performing heat exchange in the cooling heat exchanger 32 using the refrigerant whose heat is radiated in the indoor heat exchanger 22.

[0152] Furthermore, when the difference between the amount of heat obtained by the chilled-use heat exchanger 32 and the amount of heat required by the indoor unit 20 for heating is small, the refrigeration system 1 can perform heating without flowing refrigerant through the outdoor heat exchanger 15. In this case, the control device 100 fully opens the first cooling valve 51 and the outdoor refrigerant return valve 53 of the first switching mechanism 50, and the throttling mechanism 55 and the refrigerant return expansion mechanism 58 of the second switching mechanism 54. Furthermore, in a configuration including the second throttling mechanism 94 and the third throttling mechanism 95, these mechanisms are fully opened. This allows the indoor heat exchanger 22 to function as a gas cooler or radiator, and the chilled-use heat exchanger 32 to function as an evaporator, thereby heating the target space without using the outdoor heat exchanger 15. Because liquid refrigerant flows only to the chilled-use equipment 30, the opening degree of the gas refrigerant flow control valve 61 is smaller than in the cooling / dehumidifying mode, the cooling mode, and the heating mode in which the outdoor heat exchanger 15 is used.

[0153] [1-2-6. Example of control device operation] 7 and 8 are flowcharts showing an example of the operation of the refrigeration system 1. Fig. 7 shows an example of processing by the control device 100 to select an operation mode of the refrigeration system 1. Fig. 8 shows an example of processing by the control device 100 while the humidity control unit 3 is performing humidity control.

[0154] Steps S11 to S24 in Fig. 7 are executed by the control unit 101. The operation in Fig. 7 is a process for selecting an operation mode of the refrigeration system 1 during operation of the refrigeration system 1 and at the start of operation. The operation in Fig. 7 is executed, for example, at the start of operation of the refrigeration system 1, and is repeatedly executed at a preset cycle after operation of the refrigeration system 1 has started. The control device 100 starts the operation mode selected by the operation in Fig. 7, or switches the operation mode.

[0155] The control device 100 acquires a target temperature TS and a target humidity HS for air conditioning of the target space (step S11). The target temperature TS and the target humidity HS are set, for example, by operating the operation panel 132, and are stored in the storage unit 103 as part of the setting data 103a.

[0156] The control device 100 acquires the temperature T1 and humidity H1 of the target space (step S12). The temperature T1 is the temperature detected by the space temperature sensor 27, and the humidity H1 is the humidity detected by the space humidity sensor 29.

[0157] The control device 100 calculates the required humidity control amount (step S13). The required humidity control amount is found from the difference between the target humidity HS and the humidity H1. The required humidity control amount increases as the humidity H1 in the target space increases. The control device 100 determines whether the required humidity control amount is equal to or greater than a preset first threshold value (step S14).

[0158] If it is determined that the required humidity control amount is equal to or greater than the first threshold (step S14: YES), the control device 100 selects the space dehumidification mode as the operation mode of the refrigeration system 1 (step S15), and ends this process.

[0159] A large required humidity control amount indicates that the humidity H1 in the target space is high, and the target space is in a low comfort state. In particular, when the temperature T1 in the target space is higher than the target temperature TS and cooling is required, a high humidity H1 can be said to be a very low comfort state. In such a state, reducing the humidity H1 is effective in improving comfort. Therefore, by operating the refrigeration system 1 in space dehumidification mode, the comfort in the target space can be improved quickly and effectively.

[0160] In the space dehumidification mode, heat exchange by the indoor unit 20 is not performed, so the load on the refrigeration system 1 is small, and power consumption can be reduced compared to the cooling and dehumidification mode. This has the effect of improving comfort in the target space while reducing the load and power consumption on the refrigeration system 1. Furthermore, if the indoor unit 20 performs cooling operation when humidity H1 is high, it is expected that a large amount of drain water will be generated. If the temperature T1 is higher than the target temperature TS, executing the space dehumidification mode can be expected to have the effect of suppressing the subsequent generation of drain water in the indoor unit 20.

[0161] If the required humidity control amount is not equal to or greater than the first threshold (step S14: NO), the control device 100 calculates the required air conditioning amount (step S16). The required air conditioning amount is found from the difference between the target temperature TS and the temperature T1. For example, the required air conditioning amount is calculated separately for the case where the temperature T1 is lower than the target temperature TS and the case where the temperature T1 is higher than the target temperature TS.

[0162] The control device 100 determines whether the required air conditioning amount satisfies the conditions for cooling operation (step S17). If the required air conditioning amount satisfies the conditions for cooling operation (step S17: YES), the control device 100 determines whether the required humidity control amount is equal to or greater than a second threshold (step S18). The second threshold is a preset value similar to the first threshold, and is lower than the first threshold. If the required humidity control amount is equal to or greater than the second threshold (step S18: YES), the control device 100 selects the cooling and dehumidification mode as the operation mode (step S19) and ends this process.

[0163] If the required humidity control amount is not equal to or greater than the second threshold (step S18: NO), the control device 100 selects the cooling mode as the operation mode (step S20) and ends this process.

[0164] If the required air conditioning amount does not meet the conditions for cooling operation (step S17: NO), the control device 100 determines whether the required air conditioning amount meets the conditions for heating operation (step S21). If the required air conditioning amount meets the conditions for heating operation (step S21: YES), the control device 100 determines whether the required humidity control amount is equal to or greater than a second threshold (step S22). If the required humidity control amount is equal to or greater than the second threshold (step S22: YES), the control device 100 selects the heating / dehumidification mode as the operation mode (step S23) and ends this process. If the required humidity control amount is not equal to or greater than the second threshold (step S23: NO), the control device 100 selects the heating mode as the operation mode (step S24) and ends this process.

[0165] After steps S15, S19, S20, S23, and S24, if the refrigeration system 1 is in operation, the operation mode is switched. Furthermore, when the operation of the refrigeration system 1 starts, the refrigeration system 1 starts operation in the selected operation mode.

[0166] If the heating and dehumidifying mode is selected in step S23 and the refrigeration system 1 is in a state of insufficient heat, the control device 100 can perform two types of control. The first type of control is to operate the outdoor heat exchanger 15 as a gas cooler, as in the case of an excess of heat in the refrigeration system 1, and execute the heating and dehumidifying mode. The second type of control is to cancel the selection of the heating and dehumidifying mode and select the heating mode as the operating mode. When heating operation is performed, the room temperature in the target space rises, causing a decrease in relative humidity even if the humidity control unit 3 does not perform dehumidification. Therefore, switching from the heating and dehumidifying mode to the heating mode does not significantly reduce comfort in the target space.

[0167] The first threshold value, the second threshold value, the cooling operation condition, and the heating operation condition referred to in the operation of FIG.

[0168] Steps S31 to S38 in Fig. 8 are executed by the control unit 101. The operation in Fig. 8 is repeatedly executed at a preset cycle while the refrigeration system 1 is operating in any one of the space dehumidification mode, the cooling dehumidification mode, and the heating dehumidification mode 11.

[0169] The control device 100 acquires the target temperature TS and target humidity HS of the air conditioning of the target space (step S31), and acquires the temperature T1 and humidity H1 of the target space (step S32).

[0170] The control device 100 determines whether the humidity H1 satisfies the following formula (1) (step S33). HS+a In equation (1) and equations (2) and (3) described below, a is a preset constant. The value a referred to in equations (1), (2), and (3) may be different in each equation.​

[0171] If the humidity H1 satisfies the formula (1) (step S33: YES), the control device 100 increases the rotation speed of the fan 164 (step S34) and ends this process.

[0172] If the humidity H1 does not satisfy the formula (1) (step S33: NO), the control device 100 determines whether the humidity H1 satisfies the following formula (2) (step S35). HS-a≦H1≦HS+a (2)

[0173] If the humidity H1 satisfies the formula (2) (step S35: YES), the control device 100 maintains the rotation speed of the fan 164 (step S36) and ends this process.

[0174] If the humidity H1 does not satisfy the formula (2) (step S35: NO), the control device 100 determines that the humidity H1 satisfies the following formula (3) (step S37). In this case, the control device 100 reduces the rotation speed of the blower 164 (step S38) and ends this process. H1 <HS-a ···(3)

[0175] [1-3. Effects, etc.] As described above, in the first embodiment, the refrigeration system 1 includes a refrigeration circuit 2 and a humidity control unit 3. The refrigeration circuit 2 includes a low-stage compressor 11, a high-stage compressor 12, an outdoor heat exchanger 15, a gas-liquid separator 16, a plurality of use-side heat exchangers, namely an indoor heat exchanger 22 and a chilled heat exchanger 32, and a refrigerant flow path connecting these. The humidity control unit 3 controls the humidity of a target space to be air-conditioned by at least one use-side heat exchanger. The refrigeration circuit 2 includes a first flow path 90A that connects the outdoor heat exchanger 15 and the gas-liquid separator 16 and is provided with a first heat exchanger 91, and a second flow path 90B that connects the outdoor heat exchanger 15 and the gas-liquid separator 16 and is provided with a second heat exchanger 92. The refrigeration circuit 2 includes a throttling mechanism 55 provided upstream of the first heat exchanger 91 in the first flow path 90A and adjusting the flow rate of refrigerant flowing to the first heat exchanger 91, and a first throttling mechanism 93 provided upstream of the second heat exchanger 92 in the second flow path 90B and adjusting the flow rate of refrigerant flowing to the second heat exchanger 92. The humidity control unit 3 includes an outdoor air duct 152 through which air outside the target space flows, an indoor air duct 153 through which air taken in from the target space flows toward the target space, and a desiccant rotor 160 disposed across the outdoor air duct 152 and the indoor air duct 153 and driven to rotate. The first heat exchanger 91 and the second heat exchanger 92 are disposed in the indoor air duct 153, and air that has undergone heat exchange by the outdoor heat exchanger 15 is sent to the desiccant rotor 160 through the outdoor air duct 152. In a dehumidification mode in which the humidity control unit 3 dehumidifies the target space, the refrigeration system 1 causes the outdoor heat exchanger 15 to function as a gas cooler, and the throttling mechanism 55 and the first throttling mechanism 93 are set to a state that is more restricted than the fully open state.

[0176] This configuration enables the refrigeration system 1, which includes the indoor heat exchanger 22 and the chilled heat exchanger 32 as use-side heat exchangers, to dehumidify the target space, thereby enhancing the functionality of the refrigeration system 1. Specifically, the refrigerant used in the indoor heat exchanger 22 and the chilled heat exchanger 32 of the refrigeration system 1 can be used to dehumidify the target space. This reduces the air conditioning load, reducing the power consumption of the air conditioning and refrigeration equipment while maintaining comfort, thereby providing a refrigeration system 1 that utilizes comprehensive heat utilization. Furthermore, the desiccant rotor 160 is regenerated using the exhaust heat generated when the outdoor heat exchanger 15 operates as a gas cooler, thereby reducing the energy consumption required to dehumidify the target space by utilizing unused heat. Furthermore, the desiccant rotor 160 absorbs the exhaust heat from the outdoor heat exchanger 15, thereby improving the heat exchange efficiency of the outdoor heat exchanger 15. These effects are expected to improve the overall energy efficiency of the refrigeration system 1. Furthermore, efficient dehumidification can be performed by utilizing the first heat exchanger 91 and the second heat exchanger 92 arranged in the inside air duct 153. In the refrigeration circuit 2, the refrigerant that has flowed through the first heat exchanger 91 and the second heat exchanger 92 both flows into the gas-liquid separator 16, so that the complication of control of the refrigeration circuit 2 caused by providing the humidity control unit 3 in the refrigeration system 1 can be suppressed. Therefore, the refrigeration circuit 2 that conditions the air in the target space and the humidity control unit 3 that controls the humidity in the target space can be operated with high efficiency in the refrigeration system 1. Furthermore, in a store or the like where the outdoor unit 10 and indoor unit 20 are installed, the refrigeration system 1 can be realized at low cost, which can solve secondary problems such as condensation and mold that occurs as a result of condensation.

[0177] The refrigeration circuit 2 is provided with a third throttling mechanism 95 located downstream of the first heat exchanger 91 in the first flow path 90A, and which adjusts the pressure of the refrigerant flowing from the first heat exchanger 91 to the gas-liquid separator 16. The refrigeration circuit 2 is provided with a second throttling mechanism 94 located downstream of the second heat exchanger 92 in the second flow path 90B, and which adjusts the pressure of the refrigerant flowing from the second heat exchanger 92 to the gas-liquid separator 16. The refrigeration circuit 2 supplies the refrigerant from the gas-liquid separator 16 to the indoor heat exchanger 22 and the cold-set heat exchanger 32, which are use-side heat exchangers.

[0178] As a result, the pressure of the refrigerant flowing from the first heat exchanger 91 into the gas-liquid separator 16 can be adjusted by the third throttling mechanism 95, and the pressure of the refrigerant flowing from the second heat exchanger 92 into the gas-liquid separator 16 can be adjusted by the second throttling mechanism 944. As a result, refrigerant at an appropriate pressure can be supplied from the gas-liquid separator 16 to the user-side heat exchangers, and the refrigeration system can be operated with high efficiency.

[0179] In the refrigeration system 1, the humidity control unit 3 has a configuration in which the second heat exchanger 92 is arranged upstream of the desiccant rotor 160 in the inside air duct 153, and the first heat exchanger 91 is arranged downstream of the desiccant rotor 160.

[0180] This allows heat exchange to occur at positions upstream and downstream of the desiccant rotor 160 in the inside air duct 153, making it possible to efficiently dehumidify the target space and further suppress the effect on the room temperature of the target space.

[0181] Refrigeration system 1 includes a space temperature sensor 27 that measures the temperature of a target space, a space humidity sensor 29 that measures the humidity of the target space, and a control device 100 that acquires the measurement results of space temperature sensor 27 and space humidity sensor 29. Control device 100 calculates a required amount of cooling from the difference between the measurement result of space temperature sensor 27 and a target temperature, and a required amount of humidity control from the difference between the measurement result of space humidity sensor 29 and the target humidity. Based on the required amount of cooling and the required amount of humidity control, control device 100 executes control that prioritizes either humidity control of the target space or air conditioning of the target space.

[0182] As a result, either humidity control or air conditioning of the target space is given priority depending on the temperature and humidity of the target space, thereby improving the efficiency of operation of the refrigeration system 1 and maintaining comfort in the target space. For example, when humidity control of the target space is given priority, the load on the air conditioning caused by the humidity in the target space is reduced before air conditioning is performed, thereby stabilizing operation of the refrigeration system 1 and reducing power consumption.

[0183] The refrigeration system 1 includes a dew-point temperature measuring device 171 that measures the dew-point temperature of air flowing into the first heat exchanger 91, and a dew-point temperature measuring device 172 that measures the dew-point temperature of air flowing into the second heat exchanger 92. The refrigeration system 1 also includes a refrigerant pressure sensor 80 that measures the refrigerant pressure downstream of the first heat exchanger 91, and a refrigerant pressure sensor 80 that measures the refrigerant pressure downstream of the second heat exchanger 92. The control device 100 operates the throttling mechanism 55 to control the evaporation temperature of the first heat exchanger 91 to be equal to or higher than the dew-point temperature measured by the dew-point temperature measuring device 171, and operates the first throttling mechanism 93 to control the evaporation temperature of the second heat exchanger 92 to be equal to or higher than the dew-point temperature measured by the dew-point temperature measuring device 172.

[0184] This increases the relative humidity of the air that flows from the target space into the indoor air duct 153, thereby enabling effective dehumidification in the desiccant rotor 160 and preventing condensation in the first heat exchanger 91 and the second heat exchanger 92. Therefore, the air in the target space can be efficiently dehumidified while preventing condensation from occurring.

[0185] The refrigeration system 1 includes a second switching mechanism 54 that switches the flow path of the refrigerant that has left the outdoor heat exchanger 15 among a plurality of flow paths including a first flow path 90A and a second flow path 90B. The refrigeration system 1 may be configured such that the second switching mechanism 54 and the piping at the inlet of the gas-liquid separator 16 are provided with piping connection ports 181, 182, and 183 that can connect the first flow path 90A including the first heat exchanger 91 and the second flow path 90B including the second heat exchanger 92.

[0186] As a result, by configuring the first flow path 90A and the second flow path 90B to be connectable to the piping connection ports 181, 182, and 183, it is possible to retrofit the humidity control unit 3 to an existing refrigeration circuit and realize a configuration that allows humidity control in the target space.

[0187] In the refrigeration system 1, at least one of the use-side heat exchangers is an indoor heat exchanger 22 that conditions the air in the target space. The dehumidification mode includes a cooling / dehumidification mode in which the indoor heat exchanger 22 cools the target space and the humidity control unit 3 dehumidifies, and a heating / dehumidification mode in which the indoor heat exchanger 22 heats the target space and the humidity control unit 3 dehumidifies. In the cooling / dehumidification mode and the heating / dehumidification mode, the refrigeration system 1 causes the outdoor heat exchanger 15 to function as a gas cooler, and causes the cooling-type heat exchanger 32, which is a use-side heat exchanger different from the indoor heat exchanger 22, to function as an evaporator.

[0188] This allows the target space to be dehumidified by utilizing the exhaust heat generated by the outdoor heat exchanger 15 for cooling equipment such as refrigerated showcases and freezer showcases, and the exhaust heat generated during air-conditioning operation. Therefore, the highly energy-efficient refrigeration system 1 can dehumidify the target space, air-condition it, and cool the equipment.

[0189] (Embodiment 2) Next, a second embodiment will be described. [2-1. Refrigeration system configuration] 9, 10, and 11 are circuit diagrams showing a refrigeration system 1A in embodiment 2. In each of these figures, for ease of explanation, an opening and closing device in an open state is shown in white, an opening and closing device in a closed state and an expansion mechanism are shown in black, and among the refrigerant piping shown in the figures, piping through which the refrigerant flows is shown in thick lines, and piping through which the refrigerant does not flow is shown in thin lines.

[0190] The refrigeration system 1A has a refrigeration circuit 2A. The refrigeration circuit 2A is configured by adding a shutoff valve 44, a check valve 49, a pipe 56, and a shutoff valve 57 to the refrigeration circuit 2 of the refrigeration system 1 described in the first embodiment. These components are included in, for example, the outdoor unit 10A. The shutoff valve 44 and the shutoff valve 57 are connected to the control device 100 by control wiring (not shown). The shutoff valve 57 corresponds to the "first shutoff valve" in this disclosure, and the shutoff valve 44 corresponds to the "second shutoff valve" in this disclosure. The pipe 56 corresponds to the "third flow path" in this disclosure, and the check valve 49 corresponds to the "check valve" in this disclosure.

[0191] The shutoff valve 44 is a valve that can shut off the refrigerant flowing from the connection part A of the second switching mechanism 54 to the pipe 68, and is opened and closed under the control of the control device 100.

[0192] Pipe 56 is a pipe that connects the pipe extending from oil separator 14 to first heating pipe 41 to pipe 68. Pipe 56 is connected between first switching mechanism 50 and oil separator 14 and to a point in pipe 68 upstream of first throttling mechanism 93. Pipe 56 is provided with a shutoff valve 57. Shutoff valve 57 is a valve that can shut off the refrigerant flowing from oil separator 14 to first throttling mechanism 93, and is opened and closed under the control of control device 100.

[0193] Check valve 49 allows refrigerant flowing through pipe 68 from second switching mechanism 54 toward first throttling mechanism 93 to pass, and blocks refrigerant flowing in the opposite direction. For example, when shutoff valve 57 is open, check valve 49 prevents refrigerant flowing into pipe 68 from oil separator 14 from flowing into second switching mechanism 54.

[0194] The refrigeration system 1A includes the pipe 56, and by causing the refrigerant discharged from the oil separator 14 to flow through the second heat exchanger 92, the second heat exchanger 92 can be operated as a gas cooler. In this case, in the inside air duct 153, air flowing in from the air intake 156 exchanges heat with the second heat exchanger 92, becomes hot, and flows into the desiccant rotor 160. At this time, when the outdoor heat exchanger 15 is made to function as an evaporator, the outside air cooled by the outdoor heat exchanger 15 in the outdoor air passage 152 flows into the desiccant rotor 160.

[0195] That is, in the outdoor air duct 152, outdoor air with a high relative humidity passes through the desiccant rotor 160, causing the dehumidifying agent in the desiccant rotor 160 to absorb moisture. On the other hand, in the indoor air duct 153, indoor air with a low relative humidity passes through the desiccant rotor 160, causing the dehumidifying agent in the desiccant rotor 160 to be regenerated. As a result, in the refrigeration system 1A, the air in the target space is humidified by the humidity control unit 3.

[0196] In this way, the refrigeration system 1A is configured to allow the refrigerant discharged from the high-stage compressor 12 to flow into the second heat exchanger 92 and operate the second heat exchanger 92 as a gas cooler, thereby enabling humidification by the humidity control unit 3. Furthermore, the refrigeration system 1A can block the flow of refrigerant to the pipe 56 using the shutoff valve 57. Therefore, it is possible to switch between a state in which the humidity control unit 3 dehumidifies the target space, a state in which the target space is humidified, and a state in which the humidity control unit 3 does not control humidity.

[0197] [2-2. Refrigeration system operation] Fig. 9 shows the state of each switchgear when refrigeration system 1A operates in cooling and dehumidifying mode, Fig. 10 shows the state of each switchgear when refrigeration system 1A operates in heating and dehumidifying mode, and Fig. 11 shows the state of each switchgear when refrigeration system 1A operates in heating and humidifying mode. In each of these figures, the direction of refrigerant flow is indicated by an arrow.

[0198] [2-2-1. Cooling and dehumidification mode] 9, in the cooling and dehumidifying mode of the refrigeration system 1A, the shutoff valve 57 is closed and the shutoff valve 44 is opened. In this case, as in the cooling and dehumidifying mode of the refrigeration system 1 described in the first embodiment, the outdoor heat exchanger 15 operates as a gas cooler, and the indoor heat exchanger 22 and the cooling heat exchanger 32 operate as evaporators. In the humidity control unit 3, the outdoor air flowing through the outdoor air duct 152 is heated by the exhaust heat of the outdoor heat exchanger 15, thereby regenerating the desiccant rotor 160. In addition, the first heat exchanger 91 and the second heat exchanger 92 function as evaporators and cool the indoor air flowing through the indoor air duct 153.

[0199] [2-2-2. Cooling mode] The refrigeration system 1A performs cooling of a target space by the indoor unit 20 and cooling by the cooling equipment 30, while also being able to perform a cooling mode in which humidity control by the humidity control unit 3 is not performed.

[0200] The flow of refrigerant in the refrigeration system 1A in the cooling mode is the same as in the cooling and dehumidifying mode, except for the first flow path 90A and the second flow path 90B.

[0201] When the refrigeration system 1A is operated in cooling mode, the control device 100 closes the shutoff valve 44 to stop the flow of refrigerant to the second heat exchanger 92. Here, the control device 100 fully opens the first throttling mechanism 93 to prevent liquid sealing. In a configuration where the second throttling mechanism 94 is provided, the control device 100 fully opens the second throttling mechanism 94. The control device 100 also closes the shutoff valve 57.

[0202] In the cooling mode, the shutoff valve 44 and the refrigerant return expansion mechanism 58 are closed, and the refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows from the connection part A to the throttling mechanism 55. The control device 100 adjusts the opening degree of the throttling mechanism 55 so that the pressure of the refrigerant flowing into the gas-liquid separator 16 is within an appropriate range. Here, in a configuration where a third throttling mechanism 95 is provided, the control device 100 fully opens the third throttling mechanism 95. The control device 100 also stops the blower 164, and does not ventilate the inside air in the inside air passage 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15, which operates as a gas cooler.

[0203] [2-2-3. Space dehumidification mode] The refrigeration system 1A can also execute a space dehumidification mode in which the indoor unit 20 does not perform air conditioning of the target space, but instead operates the cooling equipment 30 and performs dehumidification using the humidity control unit 3. The operation of the refrigeration system 1A in the space dehumidification mode is the same as that of the refrigeration system 1. That is, in the space dehumidification mode, the cooling heat exchanger 32 functions as an evaporator, and the outdoor heat exchanger 15 functions as a gas cooler. Furthermore, because the indoor expansion mechanism 21 is fully closed, the indoor heat exchanger 22 does not function as either an evaporator or a gas cooler.

[0204] The states of the opening and closing devices in the space dehumidification mode are the same as those in the cooling dehumidification mode of the refrigeration system 1A, except that the indoor expansion mechanism 21 is fully closed. For example, in the space dehumidification mode of the refrigeration system 1A, the shutoff valve 44 is opened and the shutoff valve 57 is closed.

[0205] In the space dehumidification mode, the indoor expansion mechanism 21 is fully closed, and therefore the refrigerant does not flow to the indoor heat exchanger 22. In addition, the blower 28 provided in association with the indoor heat exchanger 22 does not operate. In this case, the outdoor heat exchanger 15, the first heat exchanger 91, and the second heat exchanger 92 operate, and the humidity control unit 3 dehumidifies the target space, as in the cooling dehumidification mode.

[0206] [2-2-4. Heating and dehumidification mode] The refrigeration system 1A performs heating and dehumidification mode when the indoor unit 20 performs heating and the amount of heat is excessive. 10, in the heating and dehumidifying mode, shutoff valve 57 is closed and shutoff valve 44 is open. The states of the other opening and closing devices are the same as in the heating and dehumidifying mode of refrigeration system 1 described in embodiment 1. In addition, with shutoff valve 44 open and shutoff valve 57 closed, the flow of refrigerant in the heating and dehumidifying mode of refrigeration system 1A is the same as in the heating and dehumidifying mode of refrigeration system 1 (FIG. 2).

[0207] In the heating / dehumidifying mode, the amount of heat is excessive, so the outdoor heat exchanger 15 operates as a gas cooler, and the indoor heat exchanger 22 and the cooling heat exchanger 32 operate as evaporators. In the humidity control unit 3, the desiccant rotor 160 is regenerated by the exhaust heat of the outdoor heat exchanger 15, and in the indoor air duct 153, the first heat exchanger 91 and the second heat exchanger 92 function as evaporators to cool the indoor air flowing through the indoor air duct 153.

[0208] [2-2-5. Heating mode] The refrigeration system 1A performs heating of a target space by the indoor unit 20 and cooling by the cooling equipment 30, while also being able to perform a heating mode in which humidity control is not performed by the humidity control unit 3. When the heating mode is performed in a state of excess heat, the flow of refrigerant is the same as in the heating and dehumidification mode, except for the first flow path 90A and the second flow path 90B.

[0209] The control device 100 closes the shutoff valve 44 to stop the flow of refrigerant to the second heat exchanger 92, and fully opens the first throttling mechanism 93 to prevent liquid seal. In a configuration where the second throttling mechanism 94 is provided, the control device 100 fully opens the second throttling mechanism 94 to prevent liquid seal. The control device 100 also closes the shutoff valve 57.

[0210] Because the shutoff valve 44 and the refrigerant return expansion mechanism 58 are closed, the refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows from the connection part A to the throttling mechanism 55. The control device 100 adjusts the opening degree of the throttling mechanism 55 so that the pressure of the refrigerant flowing into the gas-liquid separator 16 is within an appropriate range. Here, in a configuration where a third throttling mechanism 95 is provided, the control device 100 fully opens the third throttling mechanism 95. The control device 100 also stops the blower 164 so that the inside air is not ventilated in the inside air duct 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15, which operates as a gas cooler.

[0211] When the heating mode is executed in a state where the amount of heat is insufficient, the control device 100 closes the shutoff valve 44 and the shutoff valve 57. The control device 100 also fully opens the first throttling mechanism 93 and the second throttling mechanism 94. The control of other switching devices is the same as in the heating mode of the refrigeration system 1.

[0212] That is, the control device 100 fully closes the throttling mechanism 55 in the second switching mechanism 54 and adjusts the opening of the refrigerant return expansion mechanism 58 to control the evaporation temperature in the outdoor heat exchanger 15. As a result, liquid refrigerant flows from the gas-liquid separator 16 through the pipe 77 and the second pipe 74 into the outdoor heat exchanger 15. This refrigerant flows into the outdoor heat exchanger 15 with its pressure adjusted by the refrigerant return expansion mechanism 58, and the outdoor heat exchanger 15 functions as an evaporator.

[0213] The control device 100 closes the first cooling valve 51 in the first switching mechanism 50 and opens the first heating valve 52 and the outdoor refrigerant return valve 53. As a result, the refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows from the pipe 40 through the outdoor refrigerant return valve 53 to the suction side of the low-stage compressor 11.

[0214] The refrigerant flows into the indoor heat exchanger 22 from the oil separator 14 through the first heating pipe 41, and the indoor heat exchanger 22 operates as a gas cooler. The refrigerant leaving the indoor heat exchanger 22 passes through the fourth pipe 76 from the connection part C of the second switching mechanism 54, and further through the pipe 69 to flow into the gas-liquid separator 16.

[0215] The control device 100 adjusts the pressure of the refrigerant flowing into the gas-liquid separator 16 by controlling the opening degree of the third throttling mechanism 95 based on the pressure of the refrigerant passing through the first heat exchanger 91 and the pressure in the gas-liquid separator 16.

[0216] In the humidity control unit 3, the control device 100 stops the blower 164, as in the heating mode with excess heat, and does not ventilate the inside air into the inside air duct 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15 that operates as a gas cooler.

[0217] Through the above control, when there is a heat shortage, the refrigeration system 1A executes the heating mode, stops the humidity control unit 3, and allows the indoor unit 20 to perform heating and the cooling equipment 30 to perform cooling.

[0218] [2-3. Humidification using a humidity control unit] The refrigeration system 1A can humidify the air in the target space by the humidity control unit 3. In this case, the refrigeration system 1A operates the outdoor heat exchanger 15 as an evaporator and the second heat exchanger 92 as a gas cooler.

[0219] The outside air duct 152 acts as a moisture absorber, and the inside air duct 153 acts as a regenerator. In the outdoor air duct 152, the outdoor air taken in from the air intake 154 is cooled by heat exchange in the outdoor heat exchanger 15. This increases the relative humidity of the outdoor air, so that the desiccant in the desiccant rotor 160 absorbs moisture from the outdoor air.

[0220] In the inside air duct 153, the inside air taken in from the air intake 156 is heated by heat exchange in the second heat exchanger 92. As a result, the inside air, whose relative humidity has decreased, absorbs moisture from the moisture absorbent as it passes through the desiccant rotor 160, and is humidified.

[0221] When the humidity control unit 3 humidifies the target space, the refrigeration system 1A may cause the first heat exchanger 91 to function as an evaporator, or may not operate the first heat exchanger 91. The refrigeration system 1A may determine whether to operate the first heat exchanger 91 as a gas cooler based on the measurement result of the dew point temperature measuring device 172.

[0222] For example, if the dew point temperature of the inside air that has passed through the desiccant rotor 160 is equal to or higher than the room temperature of the target space, the air leaving the humidity control unit 3 may cause condensation in the target space. In this case, the refrigeration system 1A operates the first heat exchanger 91 as an evaporator, and circulates the inside air, whose temperature has been reduced to equal to or lower than the room temperature of the target space, into the target space. This prevents or suppresses condensation due to humidification in the target space. Also, for example, if the temperature of the inside air that has passed through the desiccant rotor 160 is significantly higher than the room temperature of the target space, the refrigeration system 1A may operate the first heat exchanger 91 as an evaporator to adjust the temperature of the inside air before circulating it into the target space.

[0223] When humidification is performed by the humidity control unit 3, the outdoor heat exchanger 15 and the cooling heat exchanger 32 operate as evaporators, and the indoor heat exchanger 22 operates as a gas cooler. Therefore, the refrigeration system 1A operates in a heating and humidification mode in which heating and humidification of the target space are performed together.

[0224] 11, in the heating and humidifying mode, the control device 100 closes the shutoff valve 44 and opens the shutoff valve 57. The control of the other opening and closing devices is the same as in the heating mode of the refrigeration system 1A in a state of heat shortage.

[0225] That is, the control device 100 fully closes the throttling mechanism 55 in the second switching mechanism 54 and adjusts the opening of the refrigerant return expansion mechanism 58 to control the evaporation temperature in the outdoor heat exchanger 15. As a result, liquid refrigerant flows from the gas-liquid separator 16 through the pipe 77 and the second pipe 74 into the outdoor heat exchanger 15. This refrigerant flows into the outdoor heat exchanger 15 with its pressure adjusted by the refrigerant return expansion mechanism 58, and the outdoor heat exchanger 15 functions as an evaporator.

[0226] The control device 100 closes the first cooling valve 51 in the first switching mechanism 50 and opens the first heating valve 52 and the outdoor refrigerant return valve 53. As a result, the refrigerant that has exchanged heat in the outdoor heat exchanger 15 flows from the pipe 40 through the outdoor refrigerant return valve 53 to the suction side of the low-stage compressor 11.

[0227] The refrigerant flows into the indoor heat exchanger 22 from the oil separator 14 through the first heating pipe 41, and the indoor heat exchanger 22 operates as a gas cooler. The refrigerant leaving the indoor heat exchanger 22 passes through the fourth pipe 76 from the connection part C of the second switching mechanism 54, and further through the pipe 69 to flow into the gas-liquid separator 16.

[0228] The control device 100 adjusts the pressure of the refrigerant flowing into the gas-liquid separator 16 by controlling the opening degree of the third throttling mechanism 95 based on the pressure of the refrigerant passing through the first heat exchanger 91 and the pressure in the gas-liquid separator 16.

[0229] Then, when the shutoff valve 57 is opened, the refrigerant compressed in the high-stage compressor 12 flows into the pipe 69 through the oil separator 14 and the pipe 56, and then flows into the second heat exchanger 92. On the other hand, because of the presence of the check valve 49, the refrigerant flowing from the pipe 56 into the pipe 68 does not flow to the second switching mechanism 54 side.

[0230] The control device 100 fully opens the first throttling mechanism 93. The second heat exchanger 92 operates as a gas cooler, and heats the inside air flowing toward the desiccant rotor 160 in the inside air duct 153 of the humidity control unit 3.

[0231] The refrigerant that has exchanged heat in the second heat exchanger 92 has its pressure adjusted by the second throttle mechanism 94 and flows into the gas-liquid separator 16.

[0232] In the humidity control unit 3, the control device 100 stops the blower 164, as in the heating mode with excess heat, and does not ventilate the inside air into the inside air duct 153. The control device 100 operates the blower 18 because the blower 18 is necessary for heat exchange in the outdoor heat exchanger 15 that operates as a gas cooler.

[0233] Through the above control, the refrigeration system 1A operates in the heating and humidifying mode when there is a heat shortage, and the indoor unit 20 performs heating, the cooling equipment 30 performs cooling, and the humidity control unit 3 humidifies the target space.

[0234] Fig. 12 is a psychrometric chart showing the state of air in the humidity control unit. The vertical axis of Fig. 12 represents absolute humidity, the horizontal axis represents dry-bulb humidity, and the dashed curve H in Fig. 12 represents a relative humidity of 100%.

[0235] Plots R21, R22, and R23 show the dry-bulb temperature and absolute humidity of air flowing through outdoor air duct 152. Plot R21 shows the state of air taken in through intake port 154 before passing through outdoor heat exchanger 15. This air is cooled by passing through outdoor heat exchanger 15 and reaches the state shown by plot R22. For example, air with a dry-bulb temperature of 15°C, a relative humidity of 60%, and an absolute humidity of 0.0063 kg / kg DA in plot R21 has its dry-bulb temperature reduced by passing through outdoor heat exchanger 15, resulting in plot R22 (dry-bulb temperature of 8.8°C, relative humidity of 90%, and absolute humidity of 0.0063 kg / kg DA). The change from plot R21 to plot R22 is a temperature change, so the absolute humidity remains almost unchanged, and the relative humidity increases as the temperature decreases.

[0236] When the air that has passed through the outdoor heat exchanger 15 passes through the desiccant rotor 160, moisture is removed by the desiccant in the desiccant rotor 160, resulting in the state shown by plot R23 (for example, dry-bulb temperature 16.05°C, relative humidity 13.0%, absolute humidity 0.0034 kg / kg DA). As the outdoor air passes through the desiccant rotor 160, moisture is removed by the desiccant, reducing the absolute humidity, and the dry-bulb temperature rises due to the effects of the heat of adsorption and the temperature of the desiccant rotor 160. As a result, moisture is given to the desiccant in the desiccant rotor 160 in the outdoor air duct 152.

[0237] Plots W1, W2, and W3 represent the dry-bulb temperature and absolute humidity of the air flowing through the indoor air duct 153. Plot W1 represents the state of air taken in through the air intake 156 before passing through the second heat exchanger 92. This air is heated as it passes through the second heat exchanger 92, resulting in the state shown by plot W2. For example, air with a dry-bulb temperature of 20.0°C, a relative humidity of 20%, and an absolute humidity of 0.0029 kg / kg DA in plot W1 increases in dry-bulb temperature as it passes through the second heat exchanger 92, resulting in plot W2 (dry-bulb temperature of 60.0°C, a relative humidity of 2.0%, and an absolute humidity of 0.0029 kg / kg DA). The change from plot W1 to plot W2 is primarily a temperature change, so the absolute humidity remains almost unchanged. Furthermore, the relative humidity decreases as the temperature increases.

[0238] When the air that has passed through the second heat exchanger 92 passes through the desiccant rotor 160, it removes moisture from the desiccant agent in the desiccant rotor 160, resulting in the state shown by plot W3 (for example, dry-bulb temperature 52.75°C, relative humidity 6.6%, absolute humidity 0.0058 kg / kg DA). In other words, the internal air removes moisture from the desiccant rotor 160, causing the absolute humidity to rise and the dry-bulb temperature to drop slightly.

[0239] The air that has passed through the desiccant rotor 160 is cooled by passing through the first heat exchanger 91, and reaches the state shown by plot W4 (for example, dry-bulb temperature 20.0°C, relative humidity 40%, absolute humidity 0.0058 kg / kg DA). While the temperature of the air decreases by passing through the first heat exchanger 91, the absolute humidity remains almost unchanged, and the relative humidity increases as the temperature decreases. The dry-bulb temperature of plot W4 is close to that of plot W1. In this way, the air from the target space that has flowed into the indoor air duct 153 does not change significantly in temperature and is circulated back into the target space in a humidified state.

[0240] [2-4. Effects, etc.] As described above, the refrigeration system 1A of the second embodiment has the same effects as the refrigeration system 1 of the first embodiment. Furthermore, in the second embodiment, the refrigeration system 1A includes a first switching mechanism 50, a pipe 56, a shutoff valve 57, a shutoff valve 44, and a check valve 49. The first switching mechanism 50 switches the flow path of the refrigerant discharged from the compressor among multiple flow paths including the user-side heat exchangers and the outdoor heat exchanger 15. The pipe 56 connects the first switching mechanism 50 to a portion of the second flow path 90B upstream of the first throttling mechanism 93. The shutoff valve 57 can shut off the refrigerant flowing through the pipe 56 to the first throttling mechanism 93, and the shutoff valve 44 can shut off the refrigerant flowing from the gas-liquid separator 16 to the first throttling mechanism 93. The check valve 49 allows the refrigerant to flow from the connection between the pipe 56 and the second flow path 90B to the first throttling mechanism 93 and shuts off the refrigerant flowing from the connection to the gas-liquid separator 16. When the refrigeration system 1A executes the cooling / dehumidification mode and the heating / dehumidification mode, it closes the shutoff valve 57 and opens the shutoff valve 44. When the refrigeration system 1A executes the heating / humidification mode in which the humidity control unit 3 humidifies the target space, it opens the shutoff valve 57 and closes the shutoff valve 44.

[0241] As a result, by controlling the opening and closing of the shutoff valve 44 and the shutoff valve 57, it is possible to supply refrigerant from the gas-liquid separator 16 to the second heat exchanger 92, and to supply refrigerant from the compressor to the second heat exchanger 92. In other words, it is possible to operate the second heat exchanger 92 as an evaporator, and to operate the second heat exchanger 92 as a gas cooler. Therefore, it is possible to use the humidity control unit 3 to switch between dehumidifying and humidifying the air in the target space.

[0242] The refrigeration system 1A includes a third throttling mechanism 95 located in the second flow path 90B downstream of the second heat exchanger 92. In the heating and humidifying mode, the refrigeration system 1A fully opens the first throttling mechanism 93 and reduces the pressure of the refrigerant by the second throttling mechanism 94.

[0243] As a result, by operating the second heat exchanger 92 as a gas cooler, it is possible to humidify the target space and adjust the pressure of the refrigerant flowing from the second heat exchanger 92 to the gas-liquid separator 16.

[0244] (Other embodiments) As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the first embodiment above to create new embodiments. Therefore, other embodiments will be exemplified below.

[0245] For example, the control device 100 may be a communication terminal such as a smartphone or tablet on which an app or program that transmits predetermined signals to the outdoor unit 10 and each part of the refrigeration system 1 is installed. In this case, the control device 100 may be capable of communicating with the outdoor unit 10 and each part of the refrigeration system 1 via a network consisting of a public line network, a dedicated line, other communication lines, and various communication facilities. The specific form of this network is not limited. The communication network may include at least either a wireless communication circuit or a wired communication circuit. Furthermore, the control device 100 may be a server device on which an app or program that transmits predetermined signals to the outdoor unit 10 and each part of the refrigeration system 1 is installed. The server device may be capable of communicating with the outdoor unit 10 and each part of the refrigeration system 1 via the above-mentioned network.

[0246] The units shown in Figure 6 are merely examples, and the specific implementation form is not particularly limited. In other words, it is not necessary to implement hardware corresponding to each unit individually, and it is of course possible to configure the units so that the functions are realized by a single processor executing a program. Furthermore, some of the functions realized by software in the above-described embodiments may be implemented by hardware, or some of the functions realized by hardware may be implemented by software.

[0247] The step units of the operation shown in Figures 7 and 8 are divided according to the main processing content to make it easier to understand the operation of each part of the refrigeration system 1, and the operation is not limited by the way the processing units are divided or the names of the processing units. The operation may be divided into more step units depending on the processing content. Furthermore, one step may be divided so that it includes more processing. Furthermore, the order of the steps may be changed as appropriate within the scope that does not interfere with the purpose of this disclosure.

[0248] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[0249] (Addendum) The above description of the embodiments discloses the following techniques.

[0250] (Technology 1) A refrigeration circuit having a compressor, a heat source side heat exchanger, a gas-liquid separator, a plurality of user side heat exchangers, and refrigerant flow paths connecting these, and a humidity control unit that controls humidity in a target space that is air-conditioned by at least one of the user side heat exchangers, wherein the refrigeration circuit has: a first flow path connecting the heat source side heat exchanger and the gas-liquid separator and in which a first heat exchanger is provided; a second flow path connecting the heat source side heat exchanger and the gas-liquid separator and in which a second heat exchanger is provided; a first throttle unit that is provided upstream of the first heat exchanger in the first flow path and that adjusts the flow rate of the refrigerant flowing to the first heat exchanger; and a second throttle unit that is provided upstream of the second heat exchanger in the second flow path and that adjusts the flow rate of the refrigerant flowing to the second heat exchanger. the humidity control unit comprises an outside air duct through which air outside the target space flows, an inside air duct through which air taken in from the target space flows toward the target space, and a desiccant rotor disposed across the outside air duct and the inside air duct and driven to rotate, the first heat exchanger and the second heat exchanger are disposed in the inside air duct, air that has undergone heat exchange by the heat source side heat exchanger is sent to the desiccant rotor through the outside air duct, and in a dehumidification mode in which the humidity control unit dehumidifies the target space, the heat source side heat exchanger is made to function as a condenser, and the first and second throttling sections are set to a state that is narrower than a fully open state. This allows a refrigeration system equipped with multiple use-side heat exchangers, including a use-side heat exchanger that conditions the target space, to dehumidify the target space. When dehumidifying the target space, this refrigeration system utilizes heat from the heat-source-side heat exchanger operating as a condenser to regenerate the desiccant rotor. This utilizes unused heat to reduce energy consumption related to dehumidification and increase the heat exchange efficiency of the heat-source-side heat exchanger. Therefore, in the refrigeration system, the refrigeration circuit that conditions the air in the target space and the humidity control unit that controls the humidity in the target space can be operated with high efficiency. Furthermore, by using the refrigerant in the refrigeration circuit to control the humidity in the target space, the air-conditioning load in the target space can be reduced, resulting in a refrigeration system that can reduce the overall power consumption of the air conditioning and refrigeration equipment and maintain comfort in the target space.

[0251] (Technology 2) The refrigeration system according to Technology 1, wherein the refrigeration circuit includes a third throttling unit located downstream of the first heat exchanger in the first flow path and configured to adjust the pressure of the refrigerant flowing from the first heat exchanger to the gas-liquid separator, and a fourth throttling unit located downstream of the second heat exchanger in the second flow path and configured to adjust the pressure of the refrigerant flowing from the second heat exchanger to the gas-liquid separator, and supplies the refrigerant from the gas-liquid separator to the use-side heat exchanger. As a result, the pressure of the refrigerant flowing from the first heat exchanger into the gas-liquid separator can be adjusted by the third throttle unit, and the pressure of the refrigerant flowing from the second heat exchanger into the gas-liquid separator can be adjusted by the fourth throttle unit.As a result, refrigerant at an appropriate pressure can be supplied from the gas-liquid separator to the user-side heat exchangers, allowing the refrigeration system to operate with high efficiency.

[0252] (Technology 3) The humidity control unit has a configuration in which the second heat exchanger is arranged upstream of the desiccant rotor in the inside air duct, and the first heat exchanger is arranged downstream of the desiccant rotor. The refrigeration system according to Technology 1 or Technology 2. This allows the air in the target space to exchange heat upstream and downstream of the desiccant rotor, thereby enabling efficient dehumidification and dehumidification without significantly affecting the temperature of the target space.

[0253] (Technology 4) A refrigeration system according to any one of Technology 1 to Technology 3, comprising: a space temperature sensor that measures the temperature of the target space; a space humidity sensor that measures the humidity of the target space; and a control device that acquires measurement results of the space temperature sensor and the space humidity sensor, wherein the control device calculates a required amount of cooling calculated from the difference between the measurement result of the space temperature sensor and a target temperature, and a required amount of humidity control calculated from the difference between the measurement result of the space humidity sensor and the target humidity, and performs control that prioritizes either humidity control of the target space or air conditioning of the target space based on the required amount of cooling and the required amount of humidity control. This allows either humidity control or air conditioning of the target space to be performed preferentially depending on the temperature and humidity of the target space, thereby improving the efficiency of operation of the refrigeration system and maintaining comfort in the target space.

[0254] (Technology 5) A refrigeration system according to Technology 4, comprising a first dew point temperature measuring device that measures the dew point temperature of the air flowing into the first heat exchanger, a second dew point temperature measuring device that measures the dew point temperature of the air flowing into the second heat exchanger, a first pressure measuring device that measures the refrigerant pressure downstream of the first heat exchanger, and a second pressure measuring device that measures the refrigerant pressure downstream of the second heat exchanger, wherein the control device operates the first throttling unit to control the evaporation temperature of the first heat exchanger to be equal to or higher than the dew point temperature measured by the first dew point temperature measuring device, and operates the second throttling unit to control the evaporation temperature of the second heat exchanger to be equal to or higher than the dew point temperature measured by the second dew point temperature measuring device. This increases the relative humidity of the air in the target space before it flows into the desiccant rotor, thereby enabling effective dehumidification in the desiccant rotor and preventing condensation in the first heat exchanger and the second heat exchanger.

[0255] (Technology 6) The refrigeration system according to any one of Technology 1 to Technology 5, further comprising a flow path switching unit that switches the flow path of the refrigerant that has left the heat source side heat exchanger among a plurality of flow paths including the first flow path and the second flow path, and a connection unit that can connect a humidity-controlled refrigerant circuit including the first heat exchanger and the second heat exchanger is disposed on the flow path switching unit and a piping at an inlet of the gas-liquid separator. This allows the humidity control unit to be retrofitted to an existing refrigeration circuit, adding humidity control functionality.

[0256] (Technology 7) A refrigeration system according to any one of Technologies 1 to 6, comprising: a discharge refrigerant switching unit that switches a flow path of the refrigerant discharged from the compressor among a plurality of flow paths including the user-side heat exchanger and the heat-source-side heat exchanger; a third flow path that connects the discharge refrigerant switching unit and an upstream portion of the second throttling unit in the second flow path; a first shutoff valve that can shut off refrigerant flowing through the third flow path to the second throttling unit; a second shutoff valve that can shut off refrigerant flowing from the gas-liquid separator to the second throttling unit; and a check valve that allows refrigerant to flow from a connection portion between the third flow path and the second flow path to the second throttling unit and shuts off refrigerant flowing from the connection portion to the gas-liquid separator, wherein when the dehumidification mode is performed, the first shutoff valve is closed and the second shutoff valve is opened, and when a humidification mode is performed in which the target space is humidified by the humidity control unit, the first shutoff valve is opened and the second shutoff valve is closed. This allows the second heat exchanger to operate as an evaporator or a condenser by opening and closing the shutoff valve, allowing the air in the target space to be dehumidified or humidified by switching between these functions.

[0257] (Technology 8) The refrigeration system according to Technology 7, further comprising a fourth throttling section located downstream of the second heat exchanger in the second flow path, wherein in the humidification mode, the second throttling section is fully opened and the pressure of the refrigerant is reduced by the fourth throttling section. This allows the second heat exchanger to operate as a condenser to humidify the target space.

[0258] (Technology 9) A refrigeration system according to any one of Technology 1 to Technology 8, wherein at least one of the use-side heat exchangers is an air-conditioning heat exchanger that conditions the target space, and the dehumidification mode includes a cooling / dehumidification mode in which the air-conditioning heat exchanger cools the target space and the humidity control unit dehumidifies, and a heating / dehumidification mode in which the air-conditioning heat exchanger heats the target space and the humidity control unit dehumidifies, and in the cooling / dehumidification mode and the heating / dehumidification mode, the heat source-side heat exchanger functions as a condenser, and the use-side heat exchanger different from the air-conditioning heat exchanger functions as an evaporator. This allows the exhaust heat generated in the heat source-side heat exchanger during cooling and heating to be used to dehumidify the target space, allowing the refrigeration system, which can perform air conditioning and humidity control in the target space, to operate with high efficiency. [Industrial Applicability]

[0259] The present disclosure can be suitably used as a refrigeration system that is capable of operating with high efficiency and that includes multiple user-side heat exchangers, including a heat exchanger that conditions the air in a target space, and a humidity control unit that controls the humidity in the target space. [Explanation of symbols]

[0260] 1, 1A, 1D Refrigeration System 2, 2A, 2D refrigeration circuit 3 Humidity control unit 10, 10A outdoor unit 11 Low-stage compressor (compressor) 12 High-stage compressor (compressor) 13 Accumulator 14 Oil separator 15 Outdoor heat exchanger (heat source side heat exchanger) 16 Gas-liquid separator 18, 28, 38 blowers 20 Indoor unit 21 Indoor expansion mechanism 22 Indoor heat exchanger (user side heat exchanger, air conditioning heat exchanger) 23 On-off valve 27 Space temperature sensor 29 Air humidity sensor 30 Refrigeration equipment 31 Inlet expansion mechanism for refrigeration 32 Refrigeration heat exchanger (user side heat exchanger) 33 Refrigeration outlet pressure adjustment mechanism 37 Internal temperature sensor 40, 46, 60, 68, 69, 71, 72, 77, 78 Piping 41 First heating pipe 42 First outdoor return pipe 44 Shut-off valve (second shut-off valve) 47 Flow control valve 48 Flow Control Valve 49 Check valve 50 First switching mechanism (discharge refrigerant switching unit) 51 First cooling valve 52 First heating valve 53 Outdoor refrigerant return valve 54 Second switching mechanism 55 Throttle mechanism (first throttle section) 56 Piping (third flow path) 57 Shut-off valve (first shut-off valve) 58 Refrigerant return expansion mechanism 59 Check valve 61 Gas refrigerant flow control valve 64 Internal heat exchanger 65 Liquid refrigerant flow control valve 66 Connecting piping 73 First Pipe 74 Second Pipe 75 Third Pipe 76 Fourth Pipe 80 Refrigerant pressure sensor (first pressure measuring device, second pressure measuring device) 82 Refrigerant temperature sensor 83 Oil level sensor 90A First flow path (humidity control refrigerant circuit) 90B Second flow path (humidity control refrigerant circuit) 91 1st heat exchanger 92 Second heat exchanger 93 First throttle mechanism (second throttle section) 94 Second aperture mechanism 95 Third aperture mechanism 100 control device 101 Control section 101a Operation control unit 101b Judgment section 103 Storage section 103a Setting data 150 casing 151 Divider 152 Outside air passage 153 Internal air channel 154, 156 Air intake 155, 157 exhaust port 160 Desiccant Rotor 164 Blower 171 Dew point temperature measuring device (second dew point temperature measuring device) 172 Dew point temperature measuring device (1st dew point temperature measuring device) 181, 182, 183 Piping connection port (connection part)

Claims

1. a refrigeration circuit having a compressor, a heat source side heat exchanger, a gas-liquid separator, a plurality of user side heat exchangers, and a refrigerant flow path connecting these; and a humidity control unit that controls the humidity of a target space that is air-conditioned by at least one of the user side heat exchangers, The refrigeration circuit includes: a first flow path connecting the heat source side heat exchanger and the gas-liquid separator and including a first heat exchanger; a second flow path connecting the heat source side heat exchanger and the gas-liquid separator and including a second heat exchanger; a first throttle portion provided in the first flow path upstream of the first heat exchanger and configured to adjust a flow rate of the refrigerant flowing into the first heat exchanger; a second throttle portion provided in the second flow path upstream of the second heat exchanger and configured to adjust a flow rate of the refrigerant flowing into the second heat exchanger, The humidity control unit is an outside air duct through which air outside the target space flows; an internal air duct through which air taken in from the target space flows toward the target space; a desiccant rotor disposed across the outside air duct and the inside air duct and driven to rotate; the first heat exchanger and the second heat exchanger are disposed in the inside air duct, and air that has undergone heat exchange by the heat source side heat exchanger is sent to the desiccant rotor through the outside air duct; In a dehumidification mode in which the humidity control unit dehumidifies the target space, the heat source side heat exchanger is caused to function as a condenser, and the first throttling portion and the second throttling portion are caused to be in a state narrower than a fully open state. Refrigeration system.

2. The refrigeration circuit includes: a third throttle portion located downstream of the first heat exchanger in the first flow path and configured to adjust a pressure of the refrigerant flowing from the first heat exchanger to the gas-liquid separator; a fourth throttle unit located downstream of the second heat exchanger in the second flow path and configured to adjust the pressure of the refrigerant flowing from the second heat exchanger to the gas-liquid separator, The refrigeration system according to claim 1 , wherein the refrigerant is supplied from the gas-liquid separator to the user-side heat exchanger.

3. 2. The refrigeration system according to claim 1, wherein the humidity control unit has a configuration in which the second heat exchanger is arranged upstream of the desiccant rotor in the inside air duct and the first heat exchanger is arranged downstream of the desiccant rotor.

4. a space temperature sensor that measures the temperature of the target space, a space humidity sensor that measures the humidity of the target space, and a control device that acquires the measurement results of the space temperature sensor and the space humidity sensor; 2. The refrigeration system according to claim 1, wherein the control device calculates a required cooling amount calculated from a difference between the measurement result of the space temperature sensor and a target temperature, and a required humidity control amount calculated from a difference between the measurement result of the space humidity sensor and a target humidity, and performs control to prioritize either humidity control of the target space or air conditioning of the target space based on the required cooling amount and the required humidity control amount.

5. a first dew-point temperature measuring device that measures the dew-point temperature of air flowing into the first heat exchanger, a second dew-point temperature measuring device that measures the dew-point temperature of air flowing into the second heat exchanger, a first pressure measuring device that measures the refrigerant pressure downstream of the first heat exchanger, and a second pressure measuring device that measures the refrigerant pressure downstream of the second heat exchanger, 5. The refrigeration system of claim 4, wherein the control device operates the first throttling unit to control the evaporation temperature of the first heat exchanger to be equal to or higher than the dew point temperature measured by the first dew point temperature measuring device, and operates the second throttling unit to control the evaporation temperature of the second heat exchanger to be equal to or higher than the dew point temperature measured by the second dew point temperature measuring device.

6. a flow path switching unit that switches a flow path of the refrigerant that has flowed out of the heat source side heat exchanger among a plurality of flow paths including the first flow path and the second flow path, The refrigeration system according to claim 1, wherein a connection portion capable of connecting a humidity-controlled refrigerant circuit including the first heat exchanger and the second heat exchanger is disposed in the flow path switching portion and inlet piping of the gas-liquid separator.

7. a discharge refrigerant switching unit that switches a flow path of the refrigerant discharged from the compressor among a plurality of flow paths including the user-side heat exchanger and the heat-source-side heat exchanger; a third flow path connecting the discharge refrigerant switching unit and a portion of the second flow path upstream of the second throttle unit; a first shutoff valve capable of shutting off the refrigerant flowing through the third flow path to the second throttle portion; a second shutoff valve capable of shutting off the refrigerant flowing from the gas-liquid separator to the second throttle portion; a check valve that allows the refrigerant to flow from a connection portion between the third flow path and the second flow path to the second throttle portion and blocks the refrigerant from the connection portion flowing toward the gas-liquid separator, When the dehumidification mode is executed, the first shutoff valve is closed and the second shutoff valve is opened; 7. The refrigeration system according to claim 1, wherein when a humidification mode in which the humidity control unit humidifies the target space is executed, the first shutoff valve is opened and the second shutoff valve is closed.

8. a fourth throttle portion located downstream of the second heat exchanger in the second flow path, The refrigeration system according to claim 7 , wherein in the humidification mode, the second throttle unit is fully opened and the pressure of the refrigerant is reduced by the fourth throttle unit.

9. At least one of the use-side heat exchangers is an air-conditioning heat exchanger that conditions the air in the target space, the dehumidification mode includes a cooling / dehumidification mode in which the air conditioning heat exchanger cools the target space and the humidity control unit dehumidifies the target space, and a heating / dehumidification mode in which the air conditioning heat exchanger heats the target space and the humidity control unit dehumidifies the target space, 2. The refrigeration system according to claim 1, wherein in the cooling / dehumidifying mode and the heating / dehumidifying mode, the heat source side heat exchanger functions as a condenser, and the utilization side heat exchanger different from the air conditioning heat exchanger functions as an evaporator.

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