Heat pump device

Abstract

This heat pump apparatus comprises multiple load devices, a heat source device, a relay device, and a control device. The multiple load devices adjust temperatures to be adjusted in multiple subject spaces by using a refrigerant. The heat source device adjusts the temperature of the refrigerant. The relay device is connected to the heat source device and the multiple load devices by refrigerant pipes through which the refrigerant is distributed and switches flow paths for the refrigerant on the basis of operating states of the multiple load devices. The control device controls the heat source device, the multiple load devices, and the relay device. The relay device comprises multiple three-way linear expansion valves. The three-way linear expansion valves are respectively disposed in the refrigerant pipes connected to the load devices and switch the flow paths for the refrigerant flowing through the load devices. In addition, flow rates of the refrigerant flowing through the load devices are adjusted by adjusting opening degrees of the three-way linear expansion valves in steps from a closed state to a fully opened state.

Description

Technical Field

[0001] The present disclosure relates to a heat pump device that adjusts the temperature of an object using a refrigerant.

Background Art

[0002] Conventionally, a flammable refrigerant such as R32 or R290 may be used in a heat pump device. Along with this, a function for preventing the leakage of the refrigerant into the air has been required for the heat pump device. For example, in Patent Document 1, when the control device determines that the refrigerant is leaking based on the detection results by the refrigerant pressure detection device and the refrigerant leakage detection device, the shut-off valve provided in the load device such as the indoor unit is closed to suppress the leakage of the refrigerant. A heat pump device is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in a heat pump device in which a plurality of load devices are connected to a heat source device such as an outdoor unit, a shut-off valve and a refrigerant pressure detection device may be installed in each load device during installation. In this case, due to poor installation of the shut-off valve, there is a risk of refrigerant leakage that is difficult to detect during installation, such as slow leakage.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a heat pump device that suppresses refrigerant leakage.

Means for Solving the Problems

[0006] The heat pump system according to this disclosure comprises: a plurality of load devices that adjust the temperature of temperature-controlled objects in a plurality of target spaces using a refrigerant; a heat source device that adjusts the temperature of the refrigerant; a relay device connected to the heat source device and the plurality of load devices by refrigerant piping through which the refrigerant flows, and which switches the flow path of the refrigerant based on the operating status of each of the plurality of load devices; and a control device that controls the heat source device, the plurality of load devices, and the relay device, wherein the relay device comprises a plurality of three-way linear expansion valves, each of the plurality of three-way linear expansion valves provided in the refrigerant piping connected to each of the plurality of load devices, which switches the flow path of the refrigerant flowing through each of the plurality of load devices, and adjusts the flow rate of the refrigerant flowing through each of the plurality of load devices by adjusting the degree of opening in stages from a closed state to a fully open state. [Effects of the Invention]

[0007] According to the heat pump system described herein, the relay unit is equipped with multiple three-way linear expansion valves. Each three-way linear expansion valve is installed in the refrigerant piping connected to each load device, and the flow rate of the refrigerant circulating through each load device is adjusted by adjusting the degree of opening. Therefore, there is no need to install shut-off valves between each load device and the relay unit. This helps to suppress refrigerant leakage, such as slow leaks due to faulty installation of shut-off valves. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic circuit diagram illustrating the configuration of a heat pump device according to Embodiment 1. [Figure 2] This is a block diagram illustrating the hardware configuration of the control device in Embodiment 1. [Figure 3] This flowchart illustrates the refrigerant leakage suppression process using a heat pump device according to Embodiment 1. [Figure 4] This is a schematic circuit diagram illustrating the configuration of a heat pump device according to Embodiment 2. [Figure 5]This flowchart illustrates the refrigerant leakage suppression process using a heat pump device according to Embodiment 2. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the drawings. This disclosure is not limited to the embodiments described below, and can be modified in various ways without departing from the spirit of this disclosure. Furthermore, this disclosure includes all possible combinations of the configurations shown in each of the embodiments described below.

[0010] Embodiment 1. Figure 1 is a schematic circuit diagram illustrating the configuration of the heat pump device 100 according to Embodiment 1. Embodiment 1 is explained using the example where the heat pump device 100 is an air conditioner that provides air conditioning for multiple target spaces TA. However, the heat pump device 100 may also be a water heater or the like that adjusts the temperature of water.

[0011] The heat pump system 100 has multiple indoor units 1 installed in multiple target spaces TA. In Figure 1, each target space TA is schematically represented by a dashed rectangle containing each indoor unit 1. The heat pump system 100 further includes an outdoor unit 2, a relay device 4, and a control device 6. The indoor units 1 are examples of load devices, and the outdoor unit 2 is an example of a heat source device. The outdoor unit 2 and the relay device 4 are connected by refrigerant piping 7, and the relay device 4 and the multiple indoor units 1 are connected by refrigerant piping 7, thereby forming a refrigerant circuit. The refrigerant flows through the refrigerant circuit, and the air in each target space TA is cooled or heated by the refrigerant flowing into each indoor unit 1. The air in each target space TA is an example of the air to be temperature controlled.

[0012] The heat pump device 100 according to Embodiment 1 performs full cooling operation, full heating operation, or cooling and heating operation. Full cooling operation refers to operation in which all of the multiple indoor units 1 perform cooling operation. Full heating operation refers to operation in which all of the multiple indoor units 1 perform heating operation. Cooling and heating operation refers to operation in which some of the multiple indoor units 1 perform cooling operation while the remaining multiple indoor units 1 perform heating operation. In the following, cooling and heating operation when the cooling load is greater than the heating load may be referred to as cooling-dominant operation. Also, cooling and heating operation when the heating load is greater than the cooling load may be referred to as heating-dominant operation. Furthermore, in the following, full cooling operation and cooling-dominant operation may each be referred to as first operation. And full heating operation and heating-dominant operation may each be referred to as second operation.

[0013] Furthermore, if the heat pump device 100 is a water heater or the like, which adjusts the temperature of water, then cooling operation refers to operation in which the load device cools the water by exchanging heat between the refrigerant and the water, and heating operation refers to operation in which the load device heats the water by exchanging heat between the refrigerant and the water.

[0014] The outdoor unit 2 comprises a compressor 20, a flow path switching device 21, a heat source heat exchanger 22, a heat source expansion valve 23, and an accumulator 24 inside the casing that constitutes the outer enclosure. Furthermore, the outdoor unit 2 comprises a first heat source check valve 27A, a second heat source check valve 27B, a third heat source check valve 27C, and a fourth heat source check valve 27D inside the casing. Hereafter, the casing that constitutes the outer enclosure of the outdoor unit 2 may be referred to as the heat source casing. In Figure 1, the heat source casing is schematically shown by a solid rectangle that contains the components of the outdoor unit 2, such as the compressor 20 and the flow path switching device 21. The accumulator 24, compressor 20, flow path switching device 21, heat source heat exchanger 22, and heat source expansion valve 23 are sequentially connected by refrigerant piping 7. The heat source expansion valve 23 is connected to the relay device 4 by refrigerant piping 7, and the flow path switching device 21 is connected to the relay device 4 by refrigerant piping 7. In the following, the refrigerant piping 7 connecting the heat source expansion valve 23 and the relay device 4 may be referred to as high-pressure piping 7A. Also, in the following, the refrigerant piping 7 connecting the flow path switching device 21 and the relay device 4 may be referred to as low-pressure piping 7B. Thus, the heat pump device 100 has a so-called two-pipe configuration in which the relay device 4 and the outdoor unit 2 are connected by two refrigerant pipes 7, namely high-pressure piping 7A and low-pressure piping 7B.

[0015] The compressor 20 draws in a low-temperature, low-pressure refrigerant, compresses the drawn-in refrigerant to a high-temperature, high-pressure state, and discharges it. The compressor 20 is an inverter compressor, such as a scroll type, rotary type, reciprocating type, or screw type, whose capacity can be controlled by an inverter. The drive frequency of the compressor 20 is controlled by the control device 6, which will be described later.

[0016] The flow path switching device 21 is, for example, a four-way valve, and switches the flow path direction, which is the direction in which the refrigerant flows. The heat pump device 100 switches between first operation and second operation by the switching process performed by the flow path switching device 21. The flow path switching device 21 switches the flow path direction under the control of the control device 6. In Figure 1, the solid line portion of the flow path switching device 21 indicates the refrigerant flow path during first operation, and the dashed line portion indicates the refrigerant flow path during second operation. In Figure 1, the flow path direction of the refrigerant in the outdoor unit 2 during first operation is indicated by a solid line arrow inside the rectangle representing the heat source housing, and the flow path direction of the refrigerant in the outdoor unit 2 during second operation is indicated by a dashed line arrow inside the same rectangle. Also in Figure 1, the flow path direction of the refrigerant between the outdoor unit 2 and the relay device 4 during first operation is indicated by a solid line arrow between the outdoor unit 2 and the relay device 4, and the flow path direction of the refrigerant between the outdoor unit 2 and the relay device 4 during second operation is indicated by a dashed line arrow between the outdoor unit 2 and the relay device 4. The flow path switching device 21 is not limited to the example described above, but may also be configured by combining it with other valves, such as a two-way valve or a three-way valve.

[0017] The heat source heat exchanger 22 performs heat exchange between the heat exchange target, supplied by a fan or pump (not shown), and the refrigerant. Here, the heat exchange target refers to air or water, etc., used to regulate the temperature of the refrigerant through heat exchange with it. Examples of heat exchange targets include outdoor air or water. During cooling operation, the heat source heat exchanger 22 functions as a condenser that cools and condenses the refrigerant, and during heating operation, it functions as an evaporator that heats and evaporates the refrigerant.

[0018] The heat source expansion valve 23 adjusts the flow rate of the refrigerant by adjusting its opening degree, thereby reducing the pressure of the refrigerant and causing it to expand. The heat source expansion valve 23 is a valve whose opening degree can be controlled by the control device 6, such as an electronic expansion valve. The heat source expansion valve 23 is not limited to the example described above, and may include other throttling devices such as a capillary.

[0019] The accumulator 24 is provided on the low-pressure side which is the suction side of the compressor 20. The accumulator 24 stores surplus refrigerant generated by the difference in operating states between the first operation and the second operation, and surplus refrigerant etc. for transient changes in operation. Note that the heat pump device 100 may not include the accumulator 24.

[0020] The first heat source check valve 27A is provided in the high-pressure pipe 7A. The first heat source check valve 27A allows refrigerant to flow from the outdoor unit 2 to the relay device 4 during the first operation. Also, the first heat source check valve 27A blocks the flow of refrigerant from the relay device 4 to the outdoor unit 2. The second heat source check valve 27B is provided in the low-pressure pipe 7B. The second heat source check valve 27B allows refrigerant to flow from the relay device 4 to the outdoor unit 2 during the first operation. The second heat source check valve 27B blocks the flow of refrigerant from the outdoor unit 2 to the relay device 4.

[0021] The third heat source check valve 27C is provided in the first heat source connection pipe 7C that connects the downstream side of the first heat source check valve 27A in the high-pressure pipe 7A and the downstream side of the second heat source check valve 27B in the low-pressure pipe 7B. Note that the first heat source connection pipe 7C is a part of the refrigerant pipe 7. The third heat source check valve 27C allows refrigerant to flow from the compressor 20 to the relay device 4 via the flow path switching device 21 during the second operation. The third heat source check valve 27C blocks the flow of refrigerant in the direction opposite to the flow path direction of refrigerant from the compressor 20 to the relay device 4 via the flow path switching device 21 during the second operation.

[0022] The fourth heat source check valve 27D is provided in the second heat source connection pipe 7D that connects the upstream side of the first heat source check valve 27A in the high-pressure pipe 7A and the upstream side of the second heat source check valve 27B in the low-pressure pipe 7B. Note that the second heat source connection pipe 7D is a part of the refrigerant pipe 7. The fourth heat source check valve 27D allows refrigerant from the relay device 4 to flow to the heat source expansion valve 23 during the second operation. The fourth heat source check valve 27D blocks the flow of refrigerant in the direction opposite to the flow path direction of refrigerant from the relay device 4 to the heat source expansion valve 23 during the second operation.

[0023] The indoor unit 1 includes a load expansion valve 10 and a load heat exchanger 11 inside the enclosure that constitutes the outer casing. Hereafter, the enclosure that constitutes the outer casing of the indoor unit 1 may also be referred to as the load enclosure. In Figure 1, the load enclosure is schematically shown by a solid rectangle that contains the load expansion valve 10 and the load heat exchanger 11 inside.

[0024] The load expansion valve 10 adjusts the flow rate of the refrigerant by adjusting its opening degree, thereby reducing the pressure of the refrigerant and causing it to expand. The load expansion valve 10 is a valve whose opening degree can be controlled by the control device 6, such as an electronic expansion valve. The load expansion valve 10 is not limited to the example described above, and may include other throttling devices such as a capillary.

[0025] The load heat exchanger 11 performs heat exchange between the temperature-controlled object, supplied by a fan or pump (not shown), and the refrigerant. As a result, the air in the target space TA is cooled or heated. During cooling operation, the load heat exchanger 11 functions as an evaporator, heating and evaporating the refrigerant, and during primary heating operation, it functions as a condenser, cooling and condensing the refrigerant.

[0026] In Figure 1, the direction of the refrigerant flow within the indoor unit 1 during cooling operation is indicated by a solid line arrow inside the rectangle representing the load enclosure. On the other hand, the direction of the refrigerant flow within the indoor unit 1 during heating operation is indicated by a dashed-dotted arrow inside the rectangle representing the load enclosure.

[0027] The relay unit 4 switches the flow of refrigerant according to the operating status of the indoor unit 1, distributing low-temperature refrigerant to the indoor unit 1 performing cooling operation and high-temperature refrigerant to the indoor unit 1 performing heating operation. The relay unit 4 includes a gas-liquid separator 40, a first relay heat exchanger 41, a first relay expansion valve 42, a second relay heat exchanger 43, and a second relay expansion valve 44 inside the relay housing. The relay housing refers to the housing that constitutes the outer casing of the relay unit 4. In Figure 1, the relay housing is schematically shown by a dotted rectangle that includes the components of the relay unit 4, such as the gas-liquid separator 40 and the first relay heat exchanger 41. The relay unit 4 further includes a plurality of first relay check valves 45A, a plurality of second relay check valves 45B, and a plurality of three-way linear expansion valves 46 inside the relay housing. Each first relay check valve 45A, each second relay check valve 45B, and each three-way linear expansion valve 46 are provided in correspondence with each indoor unit 1.

[0028] The relay device 4 includes a relay gas pipe 7E through which gaseous refrigerant flows and a relay liquid pipe 7F through which liquid refrigerant flows, both located within the relay enclosure. Furthermore, the relay device 4 includes a relay diversion pipe 7G and a relay merging pipe 7H located within the relay enclosure. Note that each of the relay gas pipe 7E, relay liquid pipe 7F, relay diversion pipe 7G, and relay merging pipe 7H is part of the refrigerant pipe 7.

[0029] The intermediate liquid piping 7F is connected to the gas-liquid separator 40 and, via each of the multiple first distribution pipes 7I, to each of the multiple indoor units 1. In other words, the intermediate liquid piping 7F connects the gas-liquid separator 40 to the multiple first distribution pipes 7I. Each first distribution pipe 7I is part of the refrigerant piping 7. The intermediate liquid piping 7F sequentially connects the refrigerant flow path on the primary side of the first intermediate heat exchanger 41 (described later), the first intermediate expansion valve 42, and the refrigerant flow path on the primary side of the second intermediate heat exchanger 43 (described later).

[0030] The intermediate diversion pipe 7G is connected to the intermediate liquid pipe 7F downstream of the primary refrigerant flow path of the second intermediate heat exchanger 43 (described later), and is also connected to the low-pressure pipe 7B. The intermediate diversion pipe 7G sequentially connects the second intermediate expansion valve 44, the secondary refrigerant flow path of the second intermediate heat exchanger 43 (described later), and the first intermediate heat exchanger 41.

[0031] The relay junction pipe 7H is connected to the relay liquid pipe 7F between the first relay expansion valve 42 and the second relay heat exchanger 43, and is also connected to each of the multiple indoor units 1 via each of the multiple first recovery pipes 7J. In other words, the relay junction pipe 7H connects the relay liquid pipe 7F between the first relay expansion valve 42 and the second relay heat exchanger 43, and the multiple first recovery pipes 7J. Note that the first recovery pipes 7J are part of the refrigerant pipe 7.

[0032] The intermediate gas piping 7E is connected to the gas-liquid separator 40 and, via each of the multiple second distribution pipes 7K, to each of the multiple three-way linear expansion valves 46. In other words, the intermediate gas piping 7E connects the gas-liquid separator 40 to the multiple second distribution pipes 7K. Each second distribution pipe 7K is part of the refrigerant piping 7.

[0033] In Figure 1, the flow direction of the refrigerant supplied by the relay device 4 to the indoor unit 1 performing cooling operation, and the flow direction of the refrigerant obtained from the indoor unit 1 performing cooling operation are indicated by solid arrows. In addition, the flow direction of the refrigerant supplied by the relay device 4 to the indoor unit 1 performing heating operation, and the flow direction of the refrigerant obtained from the indoor unit 1 performing heating operation are indicated by dashed arrows.

[0034] The gas-liquid separator 40 is connected to the high-pressure piping 7A, the intermediate gas piping 7E, and the intermediate liquid piping 7F, and separates the gas-liquid two-phase refrigerant flowing in from the high-pressure piping 7A into gaseous refrigerant and liquid refrigerant. The gaseous refrigerant separated in the gas-liquid separator 40 flows into the three-way linear expansion valve 46 via the intermediate gas piping 7E. On the other hand, the liquid refrigerant separated in the gas-liquid separator 40 flows into the first intermediate heat exchanger 41 via the intermediate liquid piping 7F.

[0035] The first intermediate heat exchanger 41 has a primary refrigerant flow path and a secondary refrigerant flow path. Liquid refrigerant that has flowed out from the gas-liquid separator 40 flows through the primary refrigerant flow path of the first intermediate heat exchanger 41. Refrigerant that has flowed out from the secondary refrigerant flow path of the second intermediate heat exchanger 43 flows through the secondary refrigerant flow path of the first intermediate heat exchanger 41. The refrigerant flowing through the primary refrigerant flow path is supercooled by heat exchange with the refrigerant flowing through the secondary refrigerant flow path. The secondary refrigerant flow path of the first intermediate heat exchanger 41 is connected to the low-pressure pipe 7B via the intermediate diversion pipe 7G. The refrigerant that has flowed out of the secondary refrigerant flow path of the first intermediate heat exchanger 41 flows into the low-pressure pipe 7B via the intermediate diversion pipe 7G.

[0036] The first intermediate expansion valve 42 adjusts the flow rate of the refrigerant by adjusting its opening degree, thereby reducing the pressure of the refrigerant and causing it to expand. The first intermediate expansion valve 42 is a valve whose opening degree can be controlled by the control device 6, such as an electronic expansion valve. The first intermediate expansion valve 42 reduces the pressure of the refrigerant flowing in from the first intermediate heat exchanger 41 and causes it to expand. The first intermediate expansion valve 42 is not limited to the example described above, and may include other throttling devices such as a capillary.

[0037] The second intermediate heat exchanger 43 has a primary refrigerant flow path and a secondary refrigerant flow path. The refrigerant that has flowed out from the first intermediate expansion valve 42 flows through the primary refrigerant flow path of the second intermediate heat exchanger 43. The refrigerant that has flowed out from the second intermediate expansion valve 44 flows through the secondary refrigerant flow path of the second intermediate heat exchanger 43. The refrigerant flowing through the primary refrigerant flow path of the second intermediate heat exchanger 43 is supercooled by heat exchange with the refrigerant flowing through the secondary flow path of the second intermediate heat exchanger 43.

[0038] The second relay expansion valve 44 adjusts the flow rate of the refrigerant by adjusting its opening degree, thereby depressurizing and expanding the refrigerant. The second relay expansion valve 44 is a valve whose opening degree can be controlled by the control device 6, such as an electronic expansion valve. The second relay expansion valve 44 depressurizes and expands the refrigerant flowing in from the second relay heat exchanger 43. The refrigerant after depressurization in the second relay expansion valve 44 flows into the refrigerant flow path on the secondary side of the second relay heat exchanger 43 via the relay distribution pipe 7G. Note that the second relay expansion valve 44 is not limited to the example described above, and may include other throttling devices such as a capillary tube.

[0039] Each first relay check valve 45A is provided in each first distribution pipe 7I. Each first relay check valve 45A allows refrigerant from the second relay heat exchanger 43 to flow to each indoor unit 1 via the relay liquid pipe 7F. On the other hand, each first relay check valve 45A blocks the flow of refrigerant from each indoor unit 1 to the relay liquid pipe 7F.

[0040] Each second relay check valve 45B is installed in each first recovery pipe 7J. Each second relay check valve 45B allows refrigerant to flow from each indoor unit 1 to the relay liquid pipe 7F between the first relay expansion valve 42 and the second relay heat exchanger 43. In other words, refrigerant flows from each indoor unit 1 to the relay liquid pipe 7F between the first relay expansion valve 42 and the second relay heat exchanger 43 in each first recovery pipe 7J. Each second relay check valve 45B blocks the flow of refrigerant from the relay liquid pipe 7F between the first relay expansion valve 42 and the second relay heat exchanger 43 to each indoor unit 1.

[0041] Each three-way linear expansion valve 46 is connected to the intermediate gas piping 7E via each second distribution piping 7K, and is also connected to each indoor unit 1 via the first aggregation piping 7L, which is part of the refrigerant piping 7. Furthermore, each three-way linear expansion valve 46 is connected to the low-pressure piping 7B via the second recovery piping 7M, which is part of the refrigerant piping 7. Each three-way linear expansion valve 46 switches the flow direction of the refrigerant according to the operating status of each indoor unit 1. Specifically, when the indoor unit 1 is performing cooling operation, the three-way linear expansion valve 46 switches the connection so that the indoor unit 1 and the second recovery piping 7M are in communication. Also, when the indoor unit 1 is performing heating operation, the three-way linear expansion valve 46 switches the connection so that the second distribution piping 7K and the indoor unit 1 are in communication.

[0042] The three-way linear expansion valve 46 adjusts the flow rate of the refrigerant by adjusting its opening degree, thereby reducing the pressure of the refrigerant and causing it to expand. The three-way linear expansion valve 46 is a valve whose opening degree can be controlled by a control device 6, such as an electronic expansion valve.

[0043] The following describes in detail the first and second operations of the heat pump device 100 according to Embodiment 1. First, the first operation will be described. In the first operation, the flow path switching device 21 switches the refrigerant flow path so that the discharge side of the compressor 20 is connected to the heat source heat exchanger 22, and the suction side of the compressor 20 is connected to the low-pressure piping 7B, as shown by the solid line portion of the flow path switching device 21 in Figure 1.

[0044] The three-way linear expansion valve 46, which is associated with the indoor unit 1 performing cooling operation, switches the refrigerant flow path so that the first aggregation pipe 7L and the second recovery pipe 7M are connected. If the first operation is primarily cooling operation, the three-way linear expansion valve 46, which is associated with the indoor unit 1 performing heating operation, switches the refrigerant flow path so that the first aggregation pipe 7L and the second distribution pipe 7K are connected.

[0045] Low-temperature, low-pressure refrigerant is compressed by the compressor 20 and discharged as high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 20 flows into the heat source heat exchanger 22 via the flow path switching device 21. The high-temperature, high-pressure gaseous refrigerant that flows into the heat source heat exchanger 22 condenses while exchanging heat with the heat exchange target and releasing heat, and flows out of the heat source heat exchanger 22 as high-pressure gas-liquid two-phase refrigerant or liquid refrigerant. In the first operation, during full cooling operation, the high-temperature, high-pressure gaseous refrigerant in the heat source heat exchanger 22 becomes high-pressure liquid refrigerant, and in the first operation, during cooling-focused operation, the high-temperature, high-pressure gaseous refrigerant in the heat source heat exchanger 22 becomes high-pressure gas-liquid two-phase refrigerant. The high-pressure gas-liquid two-phase refrigerant or liquid refrigerant that flows out of the heat source heat exchanger 22 flows out of the outdoor unit 2 via the first heat source check valve 27A and flows into the relay device 4.

[0046] The high-pressure gas-liquid two-phase refrigerant or liquid refrigerant that flows into the relay device 4 flows into the gas-liquid separator 40. During heating and cooling operation, the gas-liquid two-phase refrigerant is separated into high-pressure gaseous refrigerant and high-pressure liquid refrigerant in the gas-liquid separator 40. The high-pressure liquid refrigerant in the gas-liquid separator 40 flows into the refrigerant flow path on the primary side of the first relay heat exchanger 41.

[0047] The liquid refrigerant flowing into the primary side refrigerant flow path of the first intermediate heat exchanger 41 is supercooled by the refrigerant flowing in the secondary side refrigerant flow path of the first intermediate heat exchanger 41 and flows out from the primary side refrigerant flow path of the first intermediate heat exchanger 41. The liquid refrigerant that has flowed out from the primary side refrigerant flow path of the first intermediate heat exchanger 41 passes through the first intermediate expansion valve 42 and flows into the primary side refrigerant flow path of the second intermediate heat exchanger 43. The intermediate-pressure liquid refrigerant that has flowed into the primary side refrigerant flow path of the second intermediate heat exchanger 43 is further supercooled by the refrigerant flowing in the secondary side refrigerant flow path of the second intermediate heat exchanger 43 and flows out from the primary side refrigerant flow path of the second intermediate heat exchanger 43.

[0048] The liquid refrigerant flowing out of the primary side refrigerant flow path of the second intermediate heat exchanger 43 is divided, and a portion of the liquid refrigerant flows into the indoor unit 1 performing cooling operation via the first intermediate check valve 45A, which is associated with the indoor unit 1 performing cooling operation. The remaining liquid refrigerant flowing out of the primary side refrigerant flow path of the second intermediate heat exchanger 43 is depressurized and expanded by the second intermediate expansion valve 44 to become low-pressure gaseous refrigerant, which flows through the intermediate diversion piping 7G. As a result, the low-pressure gaseous refrigerant contributes to the subcooling of the refrigerant flowing in the primary side refrigerant flow paths of the first intermediate heat exchanger 41 and the second intermediate heat exchanger 43, respectively.

[0049] Liquid refrigerant flowing into the indoor unit 1 during cooling operation is depressurized and expanded by the load expansion valve 10 to become a low-temperature, low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, which then flows into the load heat exchanger 11. The low-temperature, low-pressure gas-liquid two-phase refrigerant or liquid refrigerant flowing into the load heat exchanger 11 cools the temperature-controlled object by exchanging heat with it, absorbing heat and evaporating, and then flows out of the load heat exchanger 11 as a low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant that has flowed out of the load heat exchanger 11 then flows out of the indoor unit 1 and into the relay device 4. The refrigerant that has flowed into the relay device 4 flows into the low-pressure pipe 7B via the three-way linear expansion valve 46 and the second recovery pipe 7M.

[0050] When cooling operation is performed, the high-pressure gaseous refrigerant separated in the gas-liquid separator 40 flows out of the relay device 4 via the second distribution pipe 7K and the three-way linear expansion valve 46, and flows into the indoor unit 1 performing heating operation. The high-temperature, high-pressure gaseous refrigerant that flows into the indoor unit 1 performing heating operation flows into the load heat exchanger 11, where it exchanges heat with the temperature-controlled object, dissipating heat while condensing and heating the temperature-controlled object, becoming a high-pressure liquid refrigerant that flows out of the load heat exchanger 11. The high-pressure liquid refrigerant that flows out of the load heat exchanger 11 is depressurized and expanded by the load expansion valve 10 to become a low-pressure liquid refrigerant, which flows from the indoor unit 1 to the relay device 4.

[0051] The refrigerant flowing from the indoor unit 1 performing heating operation into the relay unit 4 passes through the second relay check valve 45B, flows through the relay merging pipe 7H, and flows into the relay liquid pipe 7F between the first relay expansion valve 42 and the second relay heat exchanger 43, where it merges with the liquid refrigerant from the first relay expansion valve 42. The merged refrigerant then flows through the primary side refrigerant flow path of the second relay heat exchanger 43. A portion of the refrigerant flowing out of the second relay heat exchanger 43 passes through the first relay check valve 45A, which is associated with the indoor unit 1 performing cooling operation, and flows into the indoor unit 1 performing cooling operation, contributing to the cooling operation. Meanwhile, the remaining refrigerant flowing out of the second relay heat exchanger 43 flows into the relay branch pipe 7G, flows sequentially through the second relay expansion valve 44, the second relay heat exchanger 43, and the first relay heat exchanger 41, and flows into the low-pressure pipe 7B.

[0052] In the first operation, the refrigerant flowing through the low-pressure piping 7B flows from the relay device 4 to the outdoor unit 2, passes through the second heat source check valve 27B, the flow path switching device 21, and the accumulator 24, and is drawn into the compressor 20. Thereafter, the above-described circulation of the refrigerant is repeated.

[0053] Next, the second operation will be described. In the second operation, the control device 6 switches the refrigerant flow path of the flow path switching device 21 so that the discharge side of the compressor 20 is connected to the gas-liquid separator 40, and the suction side of the compressor 20 is connected to the heat source heat exchanger 22, as shown by the dashed line portion of the flow path switching device 21 in Figure 1.

[0054] The three-way linear expansion valve 46, which is associated with the indoor unit 1 performing heating operation, switches the refrigerant flow path so that the first aggregation pipe 7L and the second distribution pipe 7K are connected. If the second operation is primarily heating operation, the three-way linear expansion valve 46, which is associated with the indoor unit 1 performing cooling operation, switches the refrigerant flow path so that the first aggregation pipe 7L and the second recovery pipe 7M are connected.

[0055] The low-temperature, low-pressure refrigerant is compressed by the compressor 20 and discharged as a high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 20 flows out of the outdoor unit 2 via the flow path switching device 21 and the fourth heat source check valve 27D and flows into the relay device 4. The high-temperature, high-pressure gaseous refrigerant that flows into the relay device 4 flows into the relay gas piping 7E via the gas-liquid separator 40. The refrigerant flowing through the relay gas piping 7E flows into the indoor unit 1 performing heating operation via the three-way linear expansion valve 46 which is associated with the indoor unit 1 performing heating operation.

[0056] The high-temperature, high-pressure gaseous refrigerant that flows into the indoor unit 1 performing heating operation flows into the load heat exchanger 11, where it exchanges heat with the temperature-controlled object, releasing heat while condensing and heating the object. It then flows out of the load heat exchanger 11 as high-pressure liquid refrigerant. The high-pressure liquid refrigerant that flows out of the load heat exchanger 11 is depressurized and expanded by the load expansion valve 10 to become an intermediate-pressure liquid refrigerant, which flows out of the indoor unit 1 performing heating operation and then flows into the relay device 4.

[0057] The intermediate-pressure liquid refrigerant flowing from the indoor unit 1, which is performing heating operation, into the relay unit 4 passes through the second relay check valve 45B and flows through the relay junction pipe 7H. The liquid refrigerant flowing through the relay junction pipe 7H flows into the primary side refrigerant flow path of the second relay heat exchanger 43. The liquid refrigerant that has flowed into the primary side refrigerant flow path of the second relay heat exchanger 43 is supercooled by the refrigerant flowing through the secondary side refrigerant flow path of the second relay heat exchanger 43 and flows out from the primary side refrigerant flow path of the second relay heat exchanger 43.

[0058] When heating-focused operation is performed, the liquid refrigerant flowing out of the primary side refrigerant flow path of the second intermediate heat exchanger 43 is divided, and a portion of the liquid refrigerant passes through the first intermediate check valve 45A, which is associated with the indoor unit 1 performing cooling operation, and flows into the indoor unit 1 performing cooling operation. On the other hand, the remaining liquid refrigerant flowing out of the primary side refrigerant flow path of the second intermediate heat exchanger 43 flows through the intermediate diversion pipe 7G, is depressurized by the second intermediate expansion valve 44, and then flows into the secondary side refrigerant flow path of the second intermediate heat exchanger 43. The refrigerant flowing through the secondary side refrigerant flow path of the second intermediate heat exchanger 43 exchanges heat with the refrigerant flowing through the primary side refrigerant flow path of the second intermediate heat exchanger 43, and then flows out of the second intermediate heat exchanger 43 and into the secondary side refrigerant flow path of the first intermediate heat exchanger 41. The refrigerant flowing through the secondary refrigerant path of the first intermediate heat exchanger 41 exchanges heat with the refrigerant flowing through the primary refrigerant path of the first intermediate heat exchanger 41, and then flows out of the first intermediate heat exchanger 41 and into the low-pressure piping 7B.

[0059] Liquid refrigerant flowing into indoor unit 1 performing cooling operation is depressurized and expanded by load expansion valve 10 to become low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, which then flows into load heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant flowing into load heat exchanger 11 cools the temperature-controlled object by exchanging heat with it, absorbing heat and evaporating, and then flows out of load heat exchanger 11 as low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant that has flowed out of load heat exchanger 11 then flows from indoor unit 1 to relay device 4. The gaseous refrigerant that has flowed into relay device 4 passes through three-way linear expansion valve 46, which is associated with indoor unit 1 performing cooling operation, and flows into low-pressure piping 7B.

[0060] When full heating operation is performed, the refrigerant flowing out from the primary side refrigerant flow path of the second intermediate heat exchanger 43 flows through the intermediate diversion pipe 7G, is depressurized by the second intermediate expansion valve 44, and then flows into the secondary side refrigerant flow path of the second intermediate heat exchanger 43. The refrigerant flowing through the secondary side refrigerant flow path of the second intermediate heat exchanger 43 exchanges heat with the refrigerant flowing through the primary side refrigerant flow path of the second intermediate heat exchanger 43, then flows out of the second intermediate heat exchanger 43 and into the secondary side refrigerant flow path of the first intermediate heat exchanger 41. The refrigerant flowing through the secondary side refrigerant flow path of the first intermediate heat exchanger 41 exchanges heat with the refrigerant flowing through the primary side refrigerant flow path of the first intermediate heat exchanger 41, then flows out of the first intermediate heat exchanger 41 and into the low-pressure pipe 7B.

[0061] In the second operation, the refrigerant flowing through the low-pressure piping 7B flows out from the relay device 4 and into the outdoor unit 2. The refrigerant that flows into the outdoor unit 2 flows into the heat source heat exchanger 22 via the third heat source check valve 27C and the heat source expansion valve 23. The low-pressure gaseous refrigerant that flows into the heat source heat exchanger 22 exchanges heat with the heat exchange target, absorbs heat and evaporates, is further gasified, and flows out from the heat source heat exchanger 22. The low-temperature, low-pressure gaseous refrigerant that flows out from the heat source heat exchanger 22 passes through the flow path switching device 21 and the accumulator 24 and is drawn into the compressor 20. Thereafter, the above circulation is repeated.

[0062] The heat pump device 100 according to Embodiment 1 has the following configuration and functions in order to suppress further refrigerant leakage in the event of refrigerant leakage from the refrigerant circuit. The heat pump device 100 has a plurality of refrigerant leak detection sensors 9. The control device 6 communicates with each of the plurality of refrigerant leak detection sensors 9 via wired communication. In Figure 1, the control device 6 and each refrigerant leak detection sensor 9 are schematically connected by dashed lines indicating signal lines, and wired communication between the control device 6 and each refrigerant leak detection sensor 9 is illustrated as an example. However, the control device 6 may communicate wirelessly with all or some of the plurality of refrigerant leak detection sensors 9.

[0063] Each refrigerant leak detection sensor 9 is installed in each target space TA and detects refrigerant leakage in each target space TA. Each refrigerant leak detection sensor 9 detects refrigerant leakage, for example, by measuring the concentration of refrigerant in each target space TA. The refrigerant leakage detection process includes a process in which the control device 6 determines whether refrigerant leakage has occurred based on the refrigerant concentration obtained by each refrigerant leak detection sensor 9.

[0064] As described above, the control device 6 controls the compressor 20, the flow path switching device 21, the heat source expansion valve 23, the load expansion valve 10, the first relay expansion valve 42, the second relay expansion valve 44, and the three-way linear expansion valve 46. In Figure 1, the control device 6 is schematically shown to be connected to the outdoor unit 2 and the relay device 4 by dashed lines that schematically represent signal lines, etc., and the control device 6 is schematically shown to communicate with each component of the outdoor unit 2 and the relay device 4 via wired communication. However, the control device 6 may also communicate wirelessly with all or some of the components of the outdoor unit 2 and the relay device 4. Also, in Figure 1, the control device 6 is schematically shown to be connected to each indoor unit 1 by dashed lines that schematically represent signal lines, etc., and the control device 6 is schematically shown to communicate with the components of each indoor unit 1 via wired communication. However, the control device 6 may also communicate wirelessly with the components of the indoor unit 1.

[0065] The control device 6 periodically acquires detection results from each refrigerant leak detection sensor 9. The control device 6 may also acquire detection results from each refrigerant leak detection sensor 9 when each refrigerant leak detection sensor detects a refrigerant leak. When a refrigerant leak is detected by each refrigerant leak detection sensor 9, the control device 6 closes the first relay expansion valve 42, the second relay expansion valve 44, and the multiple three-way linear expansion valves 46. This suppresses the inflow of refrigerant into the multiple indoor units 1, thereby further suppressing refrigerant leakage in the multiple target spaces TA.

[0066] The control device 6 stops the operation of the compressor 20 after closing the first relay expansion valve 42, the second relay expansion valve 44, and the multiple three-way linear expansion valves 46, or in parallel with closing the first relay expansion valve 42, the second relay expansion valve 44, and the multiple three-way linear expansion valves 46.

[0067] The heat pump device 100 according to Embodiment 1 may have one or more notification devices. These one or more notification devices notify about refrigerant leakage based on instructions from the control device 6. The heat pump device 100 may have at least one notification device in each of the multiple target spaces TA. When a refrigerant leak detection sensor 9 installed in each target space TA detects a refrigerant leak, the notification device provided in each target space TA may notify about the refrigerant leak. Alternatively, the heat pump device 100 may have one notification device. When a refrigerant leak detection sensor 9 in each target space TA detects a refrigerant leak, the one or more notification devices may notify about the refrigerant leak in each target space TA.

[0068] The hardware configuration of the control device 6 in Embodiment 1 will now be described with reference to Figure 2. Figure 2 is a block diagram illustrating the hardware configuration of the control device 6 in Embodiment 1. The control device 6 can be configured with a processor 60, a memory 61, and an input / output interface circuit 62. The processor 60, the memory 61, and the input / output interface circuit 62 are connected to each other by a bus 63. The processor 60 can be, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The memory 61 can be, for example, a ROM (Read Only Memory) or a RAM (Random Access Memory). The function of the control device 6 to acquire detection results from each refrigerant leak detection sensor 9 can be realized by the input / output interface circuit 62. The function of the control device 6 to control each component of the heat pump device 100, such as the compressor 20 or a plurality of three-way linear expansion valves 46, can be realized by outputting control signals for controlling each component, obtained by the processor 60 reading and executing various programs stored in the memory 61, to each component via the input / output interface circuit 62.

[0069] The functions of the control device 6 may be obtained not only through the cooperation of software and hardware as described above, but also through dedicated hardware. For example, all or part of the control device 6 may be composed of hardware such as a CPLD (Complex Programmable Logic Device) or an FPGA (Field Programmable Gate Array).

[0070] The refrigerant leakage suppression process by the heat pump device 100 according to Embodiment 1 will be described below with reference to Figure 3. Figure 3 is a flowchart illustrating the refrigerant leakage suppression process by the heat pump device 100 according to Embodiment 1. If at least one of the multiple refrigerant leakage detection sensors 9 detects a refrigerant leak in step S1 (step S1: YES), the heat pump device 100 moves the process to step S2. If none of the multiple refrigerant leakage detection sensors 9 detect a refrigerant leak in step S1 (step S1: NO), the heat pump device 100 returns the process to step S1.

[0071] In step S2, the control device 6 closes the first relay expansion valve 42, the second relay expansion valve 44, and the multiple three-way linear expansion valves 46. In step S3, the control device 6 stops the operation of the compressor 20 and notifies one or more notification devices of the refrigerant leak. The heat pump device 100 may perform the processes of step S2 and step S3 in reverse order, or in parallel.

[0072] The following describes the effects of the heat pump device 100 according to Embodiment 1. The heat pump device 100 comprises a plurality of load devices, a heat source device, a relay device 4, and a control device 6. The plurality of load devices adjust the temperature of temperature-controlled objects in a plurality of target spaces TA using a refrigerant. The heat source device adjusts the temperature of the refrigerant. The relay device 4 is connected to the heat source device and the plurality of load devices by refrigerant piping 7 through which the refrigerant flows, and switches the flow path of the refrigerant based on the operating status of each of the plurality of load devices. The control device 6 controls the heat source device, the plurality of load devices, and the relay device 4. The relay device 4 is equipped with a plurality of three-way linear expansion valves 46. Each three-way linear expansion valve 46 is provided in the refrigerant piping 7 connected to each load device, and switches the flow path of the refrigerant flowing through each load device, and adjusts the flow rate of the refrigerant flowing through each load device by adjusting the opening degree in stages from a closed state to a fully open state.

[0073] According to the above configuration, the relay device 4 is equipped with multiple three-way linear expansion valves 46, and each three-way linear expansion valve 46 is associated with each load device. Since each three-way linear expansion valve 46 adjusts the flow rate of refrigerant circulating through each load device, there is no need to install shut-off valves between each load device and the relay device 4. Shut-off valves are often installed during the construction of the heat pump system 100, but refrigerant leakage may occur due to faulty installation. However, refrigerant leakage due to faulty shut-off valve installation, such as slow leaks, is often difficult to detect during installation. In Embodiment 1, since three-way linear expansion valves 46 are installed in place of shut-off valves in the refrigerant piping 7 built into the relay housing of the relay device 4, there is no need to install the three-way linear expansion valves 46 at the installation site when installing the relay device 4. This avoids refrigerant leakage due to faulty shut-off valve installation at the installation site.

[0074] The heat pump device 100 according to Embodiment 1 has a plurality of refrigerant leak detection sensors 9 that detect refrigerant leakage in a plurality of target spaces TA. When at least one of the plurality of refrigerant leak detection sensors 9 detects refrigerant leakage, the control device 6 closes all of the plurality of three-way linear expansion valves 46. As a result, refrigerant does not flow from the heat source device to the plurality of load devices via the relay device 4, so refrigerant leakage is suppressed and the increase in refrigerant concentration in the target space TA can be suppressed.

[0075] The relay device 4 according to Embodiment 1 comprises a relay liquid pipe 7F, a relay diversion pipe 7G, a first relay expansion valve 42, and a second relay expansion valve 44. The relay liquid pipe 7F is part of the refrigerant pipe 7 and is used to circulate liquid refrigerant from the heat source device to all or part of the multiple load devices. The relay diversion pipe 7G is part of the refrigerant pipe 7 and is used to circulate refrigerant to the heat source device. The relay diversion pipe 7G is connected to the relay liquid pipe 7F. The first relay expansion valve 42 is provided in the relay liquid pipe 7F and depressurizes and expands the liquid refrigerant from the heat source device. The second relay expansion valve 44 is provided in the relay diversion pipe 7G and depressurizes and expands the refrigerant that has flowed in from the relay liquid pipe 7F. The control device 6 closes the first relay expansion valve 42 and the second relay expansion valve 44 when at least one of the multiple refrigerant leak detection sensors 9 detects a refrigerant leak. This shuts off the flow of refrigerant to multiple load devices, thereby suppressing refrigerant leakage in the target space TA.

[0076] Embodiment 2. The heat pump device 100 according to Embodiment 2 will be described below. In Embodiment 2, the same reference numerals will be used for components that are the same as those in Embodiment 1. In Embodiment 2, the same configuration as in Embodiment 1, and the same functions as in Embodiment 1 will not be described unless there are special circumstances.

[0077] Figure 4 is a schematic circuit diagram illustrating the configuration of the heat pump device 100 according to Embodiment 2. As shown in Figure 4, the relay device 4 in Embodiment 2 is equipped with relay on-off valves 47 instead of the first relay check valves 45A in Embodiment 1. Each relay on-off valve 47 is opened when the corresponding indoor unit 1 is performing cooling operation, based on control by the control device 6. On the other hand, each relay on-off valve 47 is closed when the corresponding indoor unit 1 is performing heating operation, based on control by the control device 6.

[0078] In Embodiment 2, when a refrigerant leak detection sensor 9 in each target space TA detects a refrigerant leak, the control device 6 closes the three-way linear expansion valves 46 and relay on-off valves 47 associated with each indoor unit 1 that air-conditions each target space TA. In other words, when a refrigerant leak detection sensor 9 in any of the target spaces TA detects a refrigerant leak, the control device 6 closes the three-way linear expansion valves 46 and relay on-off valves 47 associated with the indoor unit 1 that air-conditions that target space TA. Furthermore, in Embodiment 2, when an indoor unit 1 in a target space TA where no refrigerant leak has been detected by the refrigerant leak detection sensor 9 is operating, the control device 6 sets the open / closed state of the three-way linear expansion valves 46 and relay on-off valves 47 associated with the operating indoor unit 1 to a state corresponding to that operation. This ensures that user comfort is maintained in target spaces TA where no refrigerant leak has occurred.

[0079] The control device 6 may close all three-way linear expansion valves 46 and all intermediate on-off valves 47 when any of the refrigerant leak detection sensors 9 detect a refrigerant leak. The control device 6 may close all three-way linear expansion valves 46 and all intermediate on-off valves 47 if it cannot determine which of the multiple refrigerant leak detection sensors 9 detected the refrigerant. Furthermore, the control device 6 may close all three-way linear expansion valves 46 and all intermediate on-off valves 47 if a refrigerant leak is detected by another sensor, but it cannot determine which target space TA is leaking the refrigerant. The other sensors include both or one of the suction pressure sensor 25 and the suction temperature sensor 26 provided in the refrigerant piping 7 on the suction side of the compressor 20. The suction pressure sensor 25 is a sensor that detects the pressure of the refrigerant drawn into the compressor 20, and the suction temperature sensor 26 is a sensor that detects the temperature of the refrigerant drawn into the compressor 20. The control device 6 stops the operation of the compressor 20 when it closes all three-way linear expansion valves 46 and all intermediate on-off valves 47. In this case, the control device 6 may also close the first intermediate expansion valve 42 and the second intermediate expansion valve 44.

[0080] The refrigerant leakage suppression process by the heat pump device 100 according to Embodiment 2 will now be described with reference to Figure 5. Figure 5 is a flowchart illustrating the refrigerant leakage suppression process by the heat pump device 100 according to Embodiment 2. If any of the multiple refrigerant leakage detection sensors 9 detect a refrigerant leak in step S11 (step S11: YES), the heat pump device 100 moves the process to step S12. If none of the multiple refrigerant leakage detection sensors 9 detect a refrigerant leak in step S11 (step S11: NO), the heat pump device 100 returns the process to step S11.

[0081] In step S12, the control device 6 closes the three-way linear expansion valve 46 and the relay on / off valve 47 associated with the indoor unit 1 that air-conditions the target space TA where a refrigerant leak has been detected by the refrigerant leak detection sensor 9. In step S13, the control device 6 notifies one or more notification devices of the refrigerant leak. The heat pump device 100 may perform the processes in step S12 and step S13 in reverse order, or in parallel.

[0082] The following describes the effects of the heat pump device 100 according to Embodiment 2. The relay liquid piping 7F according to Embodiment 2 is connected to a plurality of load devices via a plurality of first distribution pipes 7I. The relay device 4 is equipped with relay on-off valves 47 provided in each of the plurality of first distribution pipes 7I. When at least one of the plurality of refrigerant leak detection sensors 9 detects a refrigerant leak, the control device 6 closes all of the plurality of relay on-off valves 47. As a result, the flow of refrigerant to the plurality of load devices is cut off, and refrigerant leakage in the target space TA is suppressed.

[0083] The heat pump device 100 according to Embodiment 2 has a plurality of refrigerant leak detection sensors 9 that detect refrigerant leakage in a plurality of target spaces TA. When some of the refrigerant leak detection sensors 9 detect refrigerant leakage, the control device 6 closes some of the plurality of three-way linear expansion valves 46. The control device 6 also controls the remaining three-way linear expansion valves 46 based on the operating status of the corresponding load devices among the plurality of load devices. These plurality of three-way linear expansion valves 46 are associated with some of the load devices among the plurality of load devices that adjust the temperature of the target space TA where refrigerant leakage has been detected. As a result, the heat pump device 100 can operate in target spaces TA where there is no refrigerant leakage, and can further suppress refrigerant leakage in target spaces TA where refrigerant leakage has occurred.

[0084] The relay device 4 according to Embodiment 1 includes a relay liquid piping 7F. The relay liquid piping 7F is part of the refrigerant piping 7 and is used to distribute liquid refrigerant from the heat source device to all or part of the multiple load devices. The relay liquid piping 7F is connected to the multiple load devices via multiple first distribution pipes 7I. Each of the multiple first distribution pipes 7I is provided with a relay on-off valve 47 that corresponds to each of the multiple load devices. When some of the multiple refrigerant leak detection sensors 9 detect a refrigerant leak in a portion of the multiple target spaces TA, the control device 6 closes some of the multiple relay on-off valves 47 that correspond to load devices that adjust the temperature of the temperature-controlled targets in some of the multiple load devices, and controls the remaining relay on-off valves 47 according to the operating status of the remaining load devices that correspond to the remaining relay on-off valves 47. As a result, the heat pump device 100 can operate in the target space TA where there is no refrigerant leakage, and in the target space TA where refrigerant leakage is occurring, further refrigerant leakage can be suppressed. [Explanation of symbols]

[0085] 1 Indoor unit, 2 Outdoor unit, 4 Relay device, 6 Control device, 7 Refrigerant piping, 7A High-pressure piping, 7B Low-pressure piping, 7C First heat source connection piping, 7D Second heat source connection piping, 7E Relay gas piping, 7F Relay liquid piping, 7G Relay diversion piping, 7H Relay merging piping, 7I First distribution piping, 7J First recovery piping, 7K Second distribution piping, 7L First aggregation piping, 7M Second recovery piping, 9 Refrigerant leak detection sensor, 10 Load expansion valve, 11 Load heat exchanger, 20 Compressor, 21 Flow path switching device, 22 Heat source heat exchanger, 23 Heat source expansion valve, 24 Accumulator, 25 Intake pressure sensor, 26 Intake temperature sensor, 27A First heat source check valve, 27B Second heat source check valve, 27C Third heat source check valve, 27D Fourth heat source check valve, 40 41 Gas-liquid separator, 42 First intermediate heat exchanger, 43 First intermediate expansion valve, 44 Second intermediate expansion valve, 45A First intermediate check valve, 45B Second intermediate check valve, 46 Three-way linear expansion valve, 47 Intermediate on / off valve, 60 Processor, 61 Memory, 62 Input / output interface circuit, 63 Bus, 100 Heat pump device, TA Each target space.

Claims

1. Multiple load devices that adjust the temperature of temperature-controlled objects in multiple target spaces using a refrigerant, A heat source device for adjusting the temperature of the refrigerant, A relay device is connected to the heat source device and the plurality of load devices by refrigerant piping through which the refrigerant flows, and switches the flow path of the refrigerant based on the operating status of each of the plurality of load devices. A control device that controls the heat source device, the plurality of load devices, and the relay device, A heat pump device having, The relay device is equipped with a plurality of three-way linear expansion valves, Each of the aforementioned three-way linear expansion valves is A heat pump device provided in the refrigerant piping connected to each of the plurality of load devices, which switches the flow path of the refrigerant circulating through each of the plurality of load devices and adjusts the flow rate of the refrigerant circulating through each of the plurality of load devices by adjusting the opening degree in stages from a closed state to a fully open state.

2. The heat pump device is The system includes a plurality of refrigerant leak detection sensors that detect the leakage of the refrigerant in the plurality of target spaces, The control device is The heat pump device according to claim 1, wherein if at least one of the plurality of refrigerant leak detection sensors detects a leak of the refrigerant, all of the plurality of three-way linear expansion valves are closed.

3. The relay device is, A part of the refrigerant piping, comprising a relay liquid piping for circulating the liquid refrigerant, which has flowed in from the heat source device, to all or part of the plurality of load devices, A part of the refrigerant piping, which is connected to the intermediate liquid piping and is an intermediate diversion pipe for circulating the refrigerant to the heat source device, A first relay expansion valve is provided in the relay liquid piping and depressurizes and expands the liquid refrigerant that has flowed in from the heat source device, A second relay expansion valve is provided in the relay distribution piping and reduces the pressure of the refrigerant flowing in from the relay liquid piping to expand it, Equipped with, The control device is The heat pump device according to claim 2, wherein if at least one of the plurality of refrigerant leak detection sensors detects a leak of the refrigerant, the first relay expansion valve and the second relay expansion valve are closed.

4. The relay device is, A part of the refrigerant piping includes a relay liquid pipe for circulating the liquid refrigerant, which has flowed in from the heat source device, to all or part of the plurality of load devices. The aforementioned relay liquid piping is The plurality of load devices are connected via a plurality of first distribution pipes, Multiple relay valves are provided in the aforementioned multiple first distribution pipes. The control device is The heat pump device according to claim 2, wherein if at least one of the plurality of refrigerant leak detection sensors detects a refrigerant leak, all of the plurality of relay on / off valves are closed.

5. The heat pump device is The system includes a plurality of refrigerant leak detection sensors that detect the leakage of the refrigerant in the plurality of target spaces, The control device is If some of the multiple refrigerant leak detection sensors detect a refrigerant leak, some of the multiple three-way linear expansion valves are closed, and the remaining three-way linear expansion valves are controlled based on the operating status of the corresponding load device among the multiple load devices. Some of the aforementioned three-way linear expansion valves are The heat pump device according to claim 1, which is associated with some of the load devices among the plurality of target spaces that adjust the temperature of the temperature control target in the target space where a leak of the refrigerant has been detected.

6. The relay device is, A part of the refrigerant piping includes a relay liquid pipe for circulating the liquid refrigerant, which has flowed in from the heat source device, to all or part of the plurality of load devices. The aforementioned relay liquid piping is The plurality of load devices are connected via a plurality of first distribution pipes, Each of the plurality of first distribution pipes is provided with a relay on / off valve associated with each of the plurality of load devices. The control device is If some of the multiple refrigerant leak detection sensors detect a refrigerant leak in a portion of the multiple target spaces, some of the multiple relay valves, which are associated with load devices that adjust the temperature of the temperature-controlled target in the portion of the target spaces, will be closed. Furthermore, the heat pump apparatus according to claim 5, wherein the remaining relay on-off valves among the plurality of relay on-off valves are controlled according to the operating status of the remaining load devices among the plurality of load devices associated with the remaining relay on-off valves.

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