Refrigeration cycle device

Abstract

Provided is a refrigeration cycle device capable of minimizing deterioration in the comfort of a space to be air-conditioned even when refrigerant leakage in a utilization unit is detected and the inflow of refrigerant into the utilization unit is blocked. A refrigeration cycle device (100) is provided with a first heat source unit (2), a plurality of utilization units (1), a flow path switching unit (3), and a control unit (8). The control unit (8) controls the first heat source unit (2), the utilization unit (1), and the flow path switching unit (3). In an air-conditioning operation, if a leakage of refrigerant is detected in any of the plurality of utilization units (1) and the total capacity of the utilization units (1) other than the utilization unit (1) for which the leakage of refrigerant is detected is equal to or greater than a predetermined ratio (R) of the capacity of the first heat source unit (2), the control unit (8) performs a first control in which the total capacity of the utilization units (1) is equal to or greater than a predetermined ratio (R) of the capacity of the first heat source unit (2). The flow path switching means (3) blocks the inflow of the refrigerant into the utilization unit (1) in which the leakage of the refrigerant has been detected, and continues the operation of the utilization units (1) other than the utilization unit (1) in which the leakage of the refrigerant has been detected.

Description

Technical Field

[0001] This disclosure relates to a refrigeration cycle apparatus. Background Technology

[0002] Patent document 1 (International Publication No. 2016 / 129027) discloses an air conditioning device comprising: multiple flow interruption devices disposed between multiple heat source units and indoor units to block the flow of refrigerant in refrigerant piping; multiple leakage detection units for detecting refrigerant leakage from each heat source unit; and a control device for controlling the operation of the multiple heat source units, indoor units, and flow interruption devices.

[0003] When the control unit of this air conditioning system detects a refrigerant leak in its leak detection section, it activates a disconnection device connected to the heat source unit where the refrigerant leak has occurred. If some disconnection devices are active and others are inactive, the control unit determines the limited heat exchange capacity of the indoor unit when operating the heat source unit connected to the inactive disconnection device, and controls the operation of the heat source unit or indoor unit up to this limited heat exchange capacity. Therefore, the air conditioning system of Patent Document 1 minimizes the deterioration of comfort in the air-conditioned space even when refrigerant leakage is blocked. Summary of the Invention

[0004] The technical problem that the invention aims to solve

[0005] When a refrigerant leak is detected in the operating unit (indoor unit), and the flow of refrigerant to the operating unit where the leak occurred is blocked, there is still room for research on how to determine whether to continue operating other operating units.

[0006] The purpose of this disclosure is to provide a refrigeration circulation device that can minimize the deterioration of comfort in the air-conditioned space even when a refrigerant leak is detected in the utilization unit and the flow of refrigerant to the utilization unit is blocked.

[0007] Technical solutions adopted to solve technical problems

[0008] The first-view refrigeration cycle unit operates the air conditioning system. The refrigeration cycle unit includes a first heat source unit, multiple utilization units, a flow path switching unit, and a control unit.

[0009] A flow path switching unit is located between the first heat source unit and the utilization unit to switch the flow of refrigerant between the two units. The control unit controls the first heat source unit, the utilization unit, and the flow path switching unit.

[0010] During air conditioner operation, if a refrigerant leak is detected in any of the multiple utilization units, and the total capacity of the utilization units other than the one where the refrigerant leak was detected is greater than or equal to a predetermined proportion of the capacity of the first heat source unit, the control unit performs a first control. In the first control, the flow path switching unit blocks the flow of refrigerant to the utilization unit where the refrigerant leak was detected, and allows the operation of the utilization units other than the one where the refrigerant leak was detected to continue.

[0011] According to this refrigeration cycle apparatus, even if the flow of refrigerant to the utilization unit where a refrigerant leak has occurred is blocked, the operation of the remaining utilization units can continue. Therefore, even if a refrigerant leak is detected in a utilization unit and the flow of refrigerant to the utilization unit is blocked, this refrigeration cycle apparatus can minimize the deterioration of the comfort of the air-conditioned space.

[0012] The second viewpoint of the refrigeration cycle device is based on the first viewpoint of the refrigeration cycle device. During air conditioning operation, when a refrigerant leak is detected in any of the multiple utilization units, and the total capacity of the utilization units other than the one where the refrigerant leak was detected is less than the aforementioned predetermined ratio of the capacity of the first heat source unit, the control unit performs a second control. In the second control, the flow path switching unit blocks the inflow of refrigerant to the utilization unit where the refrigerant leak was detected, and stops the operation of all utilization units, including the one where the refrigerant leak was detected.

[0013] Therefore, this refrigeration cycle device suppresses the decrease in comfort caused by the inability to maintain operation at the desired capacity.

[0014] The third viewpoint of the refrigeration cycle device is based on the first or second viewpoint of the refrigeration cycle device, and the air conditioning operation includes defrosting operation. The specified ratio is the ratio of the capacity of the utilization unit to the capacity of the first heat source unit, which enables the first heat source unit to ensure the heat required for the refrigeration cycle device to perform defrosting operation.

[0015] This refrigeration cycle unit can perform defrosting operation while suppressing the deterioration of comfort in the air-conditioned space when the flow of refrigerant to the utilization unit is blocked.

[0016] The fourth viewpoint of the refrigeration cycle device is based on the third viewpoint of the refrigeration cycle device. When the control unit determines that there is no plan to perform defrost operation, during air conditioning operation, even if a refrigerant leak is detected in any of the multiple utilization units, and the total capacity of the utilization units other than the utilization unit where the refrigerant leak was detected is less than the aforementioned specified ratio of the capacity of the first heat source unit, the control unit also performs first control.

[0017] This refrigeration cycle device allows the remaining utilization units to continue operating. Therefore, even if a refrigerant leak is detected in a utilization unit and the flow of refrigerant to that unit is blocked, this refrigeration cycle device can minimize the deterioration of comfort in the air-conditioned space.

[0018] The fifth viewpoint's refrigeration cycle device is based on any of the first to fourth viewpoints' refrigeration cycle devices, with the utilization unit having a utilization heat exchanger. In the first control, the control unit adjusts the target evaporation temperature Te or target condensation temperature Tc in the utilization heat exchanger of the continuing-operating utilization unit based on the capacity of the utilization unit where the refrigerant inflow is blocked.

[0019] In this refrigeration cycle unit, the continued operation of the utilization unit compensates for the reduced output of the utilization unit that has stopped operating due to the blockage of refrigerant inflow. Therefore, the deterioration of the comfort of the air-conditioned space can be minimized.

[0020] The refrigeration cycle device of the sixth viewpoint is based on the refrigeration cycle device of any of the first to fifth viewpoints. In the first control, the control unit performs protection control based on the capacity of the utilization unit whose refrigerant inflow is blocked.

[0021] This refrigeration cycle unit can suppress equipment damage caused by the execution of the first control.

[0022] The refrigeration cycle device of the seventh viewpoint is based on the refrigeration cycle device of any of the first to sixth viewpoints, and further includes a second heat source unit. A flow path switching unit is also provided between the second heat source unit and the multiple utilization units to switch the flow of refrigerant between the second heat source unit and the multiple utilization units.

[0023] When the control unit performs the first control, it causes the second heat source unit to compensate for the capacity of the utilization unit whose refrigerant inflow has been blocked.

[0024] In the refrigeration cycle unit, in the first control, the second heat source unit compensates for the reduced output of the utilization unit when the refrigerant inflow is blocked and the unit stops operating, thus minimizing the deterioration of the comfort of the air-conditioned space. Attached Figure Description

[0025] Figure 1 This is a schematic structural diagram of the refrigeration cycle device 100.

[0026] Figure 2 This is a block diagram of control unit 8.

[0027] Figure 3This is a flowchart illustrating the control process in case of refrigerant leakage.

[0028] Figure 4 This is a flowchart illustrating the control process for refrigerant leakage control in the refrigeration cycle device 100 of Modified Example A.

[0029] Figure 5 This is a schematic structural diagram of the refrigeration cycle device 100 of variant D. Detailed Implementation

[0030] <Implementation Method>

[0031] (1) Overall structure

[0032] The refrigeration cycle unit 100 operates the air conditioning system in the target space through a vapor compression refrigeration cycle (specifically, full cooling operation, full heating operation, defrosting operation, and simultaneous cooling and heating operation). The target space is, for example, the space within a building such as an office building, commercial facility, or residence. Furthermore, this refrigeration cycle unit is only one example of a refrigeration cycle unit; the heat exchanger disclosed herein can also be used in other refrigeration cycle units, such as refrigerators, freezers, water heaters, and underfloor heating systems.

[0033] like Figure 1 As shown, the refrigeration cycle device 100 mainly includes three utilization units 1, one heat source unit 2, three flow path switching units 3, one liquid refrigerant connecting pipe 5, one low-pressure gas refrigerant connecting pipe 6, one high-pressure gas refrigerant connecting pipe 7, and one control unit 8. Furthermore, the number of utilization units 1 and flow path switching units 3 is not limited to three; it can also be two or more.

[0034] The liquid refrigerant connecting pipe 5, the low-pressure gas refrigerant connecting pipe 6, and the high-pressure gas refrigerant connecting pipe 7 are refrigerant connecting pipes that connect the utilization unit 1 and the heat source unit 2. In the refrigeration cycle device 100, the utilization unit 1 and the heat source unit 2 are connected via the liquid refrigerant connecting pipe 5, the low-pressure gas refrigerant connecting pipe 6, and the high-pressure gas refrigerant connecting pipe 7, thereby forming the refrigerant circuit 9.

[0035] In addition to operating the air conditioner, the refrigeration cycle unit 100 also controls refrigerant leakage. The purpose of this refrigerant leakage control is to minimize the deterioration of the comfort of the air-conditioned space while suppressing further refrigerant leakage when a refrigerant leak is detected in any of the multiple utilization units 1.

[0036] (2) Detailed structure

[0037] (2-1) Using Unit 1

[0038] The utilization unit 1 mainly includes a heat exchanger 11, a fan 12, an expansion mechanism 13, a liquid refrigerant pipe 14, a gaseous refrigerant pipe 15, and a refrigerant sensor 16.

[0039] The following discussion addresses the need to differentiate between the three utilization units 1 and the devices possessed by each utilization unit 1, as follows: Figure 1 As shown, one of the suffixes a, b, or c is recorded at the end of the reference numerals of the utilizing unit 1 and the devices possessed by each utilizing unit 1.

[0040] (2-1-1) Using heat exchanger 11

[0041] Heat exchanger 11 is used to exchange heat between the refrigerant and the air transported by the airflow generated by fan 12. The liquid side of heat exchanger 11 is connected to liquid refrigerant connecting pipe 5 via liquid refrigerant pipe 14, and the gas side is connected to flow path switching unit 3 via gas refrigerant pipe 15.

[0042] (2-1-2) Using fan 12

[0043] Air is supplied to the heat exchanger 11 by the fan 12.

[0044] (2-1-3) Using expansion mechanism 13

[0045] The pressure and flow rate of the refrigerant flowing in the liquid refrigerant pipe 14 are regulated by the expansion mechanism 13. The expansion mechanism 13 is installed in the liquid refrigerant pipe 14.

[0046] (2-1-4) Refrigerant sensor 16

[0047] The refrigerant sensor 16 is installed at the location of the utilization unit 1 to detect refrigerant. In other words, the refrigerant sensor 16 detects refrigerant leaks in the air-conditioned space.

[0048] (2-2) Heat source unit 2

[0049] The heat source unit 2 mainly includes a compressor 21, a first three-way valve 22, a second three-way valve 23, a heat source heat exchanger 24, a heat source expansion mechanism 25, and a heat source fan 26.

[0050] (2-2-1) Compressor 21

[0051] The compressor 21 draws in low-pressure refrigerant from the refrigerant circuit 9 via the suction section 21a, compresses the refrigerant via a compression mechanism (not shown), and discharges it to the refrigerant circuit 9 via the discharge section 21b.

[0052] The suction section 21a of the compressor 21 is connected to the low-pressure gas refrigerant connecting pipe 6, and the discharge section 21b is connected to the first port 22a of the first three-way valve 22 and the first port 23a of the second three-way valve 23 (both described later).

[0053] (2-2-2) First three-way valve 22 and second three-way valve 23

[0054] The first three-way valve 22 has three ports: a first port 22a, a second port 22b, and a third port 22c. The first port 22a of the first three-way valve 22 is connected to the discharge section 21b of the compressor 21, the second port 22b is connected to the gas side of the heat exchanger 24, and the third port 22c is connected to the suction section 21a of the compressor 21.

[0055] The second three-way valve 23 has three ports: a first port 23a, a second port 23b, and a third port 23c. The first port 23a of the second three-way valve 23 is connected to the discharge section 21b of the compressor 21, the second port 23b is connected to the high-pressure gas refrigerant connecting pipe 7, and the third port 23c is connected to the low-pressure gas refrigerant connecting pipe 6 and the suction section 21a of the compressor 21.

[0056] The first three-way valve 22 and the second three-way valve 23 can change between a state in which the first port 22a, 23a is connected to the second port 22b, 23b while the third port 22c, 23c is closed, and a state in which the second port 22b, 23b is connected to the third port 22c, 23c while the first port 22a, 23a is closed.

[0057] (2-2-3) Heat source heat exchanger 24

[0058] The heat exchanger 24 allows the refrigerant flowing inside to exchange heat with a heat source (such as the air at the location of the heat source unit 2).

[0059] The gas side of the heat source heat exchanger 24 is connected to the second port 22b of the first three-way valve 22, and the liquid side is connected to the liquid refrigerant connecting pipe 5 via the heat source expansion mechanism 25.

[0060] (2-2-4) Heat source expansion mechanism 25

[0061] The heat source expansion mechanism 25 regulates the pressure or flow rate of the refrigerant flowing inside it. The heat source expansion mechanism 25 is installed on the piping of the liquid side of the heat source heat exchanger 24 and the piping 5 that is connected to the liquid refrigerant.

[0062] (2-2-5) Heat source fan 26

[0063] The heat source fan 26 supplies external air, which serves as a heat source, to the heat source heat exchanger 24.

[0064] (2-3) Flow path switching unit 3

[0065] The flow path switching unit 3 is disposed between the heat source unit 2 and each utilization unit 1 to switch the flow of refrigerant between the first heat source unit and the utilization unit 1. The flow path switching unit 3 has a first branch pipe 31, a second branch pipe 32, a first shut-off valve 33 and a second shut-off valve 34.

[0066] The following describes a scenario where it is necessary to differentiate between the three flow path switching units 3, such as... Figure 1 As shown, one of the suffixes a, b, and c that are marked in the corresponding utilization unit 1 will be recorded at the end of the flow path switching unit 3 and the device possessed by the flow path switching unit 3.

[0067] (2-3-1) First branch pipe 31 and second branch pipe 32

[0068] The first branch pipe 31 is a piping that connects the gaseous refrigerant pipe 15 of the utilization unit 1 to the low-pressure gaseous refrigerant connecting pipe 6. The second branch pipe 32 is a piping that connects the gaseous refrigerant pipe 15 of the utilization unit 1 to the high-pressure gaseous refrigerant connecting pipe 7.

[0069] (2-3-2) First shut-off valve 33 and second shut-off valve 34

[0070] The first shut-off valve 33 is a solenoid valve that can be freely opened and closed and is located on the first branch pipe 31. The second shut-off valve 34 is a solenoid valve that can be freely opened and closed and is located on the second branch pipe 32.

[0071] By closing the first shut-off valve 33, the flow of refrigerant via the first branch pipe 31 is blocked. Furthermore, by closing the second shut-off valve 34, the flow of refrigerant via the second branch pipe 32 is blocked.

[0072] (2-4) Control Unit 8

[0073] The controller 8 controls the operation of various devices that constitute the refrigeration cycle unit 100.

[0074] like Figure 2 As shown, the control unit 8 is electrically connected to the utilizing fan 12, the utilizing expansion mechanism 13, the refrigerant sensor 16, the compressor 21, the first three-way valve 22, the second three-way valve 23, the heat source expansion mechanism 25, the heat source fan 26, the first shut-off valve 33, and the second shut-off valve 34 in a manner capable of transmitting and receiving signals. The control unit 8 can also be electrically connected to various sensors (not shown) installed in the utilizing unit 1 and the heat source unit 2. The control unit 8 can also communicate with a remote control (not shown) operated by a user of the refrigeration cycle device 100.

[0075] The control unit 8 is implemented by a computer. The control unit 8 includes a control processing unit and a storage unit (both omitted from the diagram). The control processing unit is a processor such as a CPU or GPU. The control processing unit reads the program stored in the storage unit and performs prescribed image processing or computational processing according to the program. Furthermore, the control processing unit writes the computation results to the storage unit according to the program, or reads information stored in the storage unit according to the program.

[0076] The storage device stores the rated capacity of each utilization unit 1, the rated capacity of the first heat source unit 2, and a specified ratio R (described later).

[0077] (3) Operation of the refrigeration circulation device 100

[0078] (3-1) Air conditioner operation

[0079] During air conditioning operation, the control unit 8 of the refrigeration cycle unit 100 controls the various devices constituting the refrigeration cycle unit 100 in the manner described below. Although detailed descriptions are omitted, the control unit 8 appropriately controls the rotational speeds of the utilizing fan 12 and the heat source fan 26 during any operation.

[0080] (3-1-1) Full refrigeration operation

[0081] Full refrigeration operation is the operation in which all utilization units 1 perform refrigeration operation.

[0082] During full refrigeration operation, the first port 22a of the first three-way valve 22 is connected to the second port 22b. In addition, in each flow path switching unit 3, the first flow interruption valve 33 is turned on and the second flow interruption valve 34 is turned off.

[0083] Furthermore, with all the second shut-off valves 34 closed, the refrigerant hardly passes through the second three-way valve 23. Therefore, the state of the second three-way valve 23 is not limited.

[0084] When compressor 21 starts, the refrigerant discharged from compressor 21 flows through heat source heat exchanger 24 after passing through the first three-way valve 22. In heat source heat exchanger 24, the refrigerant dissipates heat to the outdoor air and condenses. The condensed refrigerant in heat source heat exchanger 24 passes through heat source expansion mechanism 25, which is set to be fully open, flows through liquid refrigerant connecting pipe 5, and is distributed to each utilization unit 1.

[0085] In all utilization units 1, the refrigerant is depressurized to a low pressure and flows through the utilization heat exchanger 11 as it passes through the utilization expansion mechanism 13. In the utilization heat exchanger 11, the refrigerant absorbs heat from the air in the air-conditioned space and evaporates. As a result, cooling is performed on the air-conditioned space corresponding to utilization unit 1. The opening degree of the utilization expansion mechanism 13 is adjusted according to the superheat of the refrigerant obtained by a temperature sensor (not shown) or the like.

[0086] The refrigerant flowing out from each utilization unit 1 flows through the first branch pipe 31 of each flow path switching unit 3 and converges in the low-pressure gas refrigerant connecting pipe 6. The refrigerant that has converged in the low-pressure gas refrigerant connecting pipe 6 is drawn into the compressor 21 and compressed again.

[0087] (3-1-2) Full heating operation

[0088] Full heating operation is the operation in which all utilization units 1 are in heating mode.

[0089] During full heating operation, the second port 22b of the first three-way valve 22 is connected to the third port 22c, and the first port 23a of the second three-way valve 23 is connected to the second port 23b. In addition, the first flow-stopping valve 33 of each flow path switching unit 3 is closed, and the second flow-stopping valve 34 is open.

[0090] When compressor 21 starts, the refrigerant discharged from compressor 21 flows through the high-pressure gas refrigerant connecting pipe 7 after passing through the second three-way valve 23, and is then distributed to the second branch pipe 32 of each flow path switching unit 3. After passing through each flow path switching unit 3, the refrigerant flows to the corresponding utilization unit 1.

[0091] In all utilization units 1, the refrigerant condenses by dissipating heat to the air in the air-conditioned space within the utilization heat exchanger 11. As a result, heating is performed on the air-conditioned space corresponding to utilization unit 1. The refrigerant condensed in the utilization heat exchanger 11 then passes through the utilization expansion mechanism 13. The utilization expansion mechanism 13 adjusts its opening degree based on the subcooling of the refrigerant determined by a temperature sensor (not shown) or similar means.

[0092] The refrigerant flowing out of each utilization unit 1 converges in the liquid refrigerant connecting pipe 5. After converging in the liquid refrigerant connecting pipe 5, the refrigerant is depressurized to a low pressure when passing through the heat source expansion mechanism 25 and flows through the heat source heat exchanger 24. In the heat source heat exchanger 24, the refrigerant absorbs heat from the outdoor air and evaporates. After evaporating in the heat source heat exchanger 24, the refrigerant is drawn into the compressor 21 and compressed again after passing through the first three-way valve 22.

[0093] (3-1-3) Defrosting Operation

[0094] The purpose of defrosting operation is to remove frost that forms on the outer surface of the heat source heat exchanger 24 when operating in full heating mode, especially in environments with low outside air temperatures, such as winter. During defrosting operation, the control unit 8 stops the heat source fan 26 while simultaneously performing the same refrigeration cycle as in full cooling operation. As a result, the frost formed on the outer surface of the heat source heat exchanger 24 is removed through heat dissipation from the refrigerant that has condensed in the heat source heat exchanger 24. The operation of the various devices constituting the refrigeration cycle device 100 during defrosting operation is the same as in full cooling operation, except for the operation of the heat source fan 26; therefore, detailed descriptions are omitted.

[0095] (3-2) Simultaneous operation of hot and cold water

[0096] Simultaneous heating and cooling operation refers to the operation in which one part of unit 1 is used for heating the air-conditioned space, while the remaining part of unit 1 is used for cooling the air-conditioned space. Simultaneous heating and cooling operation includes first simultaneous heating and cooling operation and second simultaneous heating and cooling operation.

[0097] (3-2-1) The first heating and cooling systems operate simultaneously.

[0098] The first simultaneous heating and cooling operation refers to a heating main unit operation in which the number of utilization units 1 performing heating operation is greater than the number of utilization units 1 performing cooling operation. The following explanation will use the case where utilization units 1a and 1b perform heating operation and utilization unit 1c performs cooling operation as an example.

[0099] During the first simultaneous hot and cold operation, the first port 22a of the first three-way valve 22 is connected to the second port 22b, and the first port 23a of the second three-way valve 23 is connected to the second port 23b. Furthermore, in the flow path switching units 3a and 3b corresponding to the utilization units 1a and 1b, the first flow interruption valve 33 is closed, and the second flow interruption valve 34 is open. Additionally, in the flow path switching unit 3c corresponding to the utilization unit 1c, the first flow interruption valve 33 is open, and the second flow interruption valve 34 is closed.

[0100] When compressor 21 starts, the refrigerant discharged from compressor 21 is diverted to the first three-way valve 22 and the second three-way valve 23. The refrigerant after passing through the first three-way valve 22 condenses in the heat source heat exchanger 24, then passes through the heat source expansion mechanism 25 adjusted to a predetermined opening and flows through the liquid refrigerant connecting pipe 5. On the other hand, the refrigerant after passing through the second three-way valve 23 flows through the high-pressure gas refrigerant connecting pipe 7 and flows to the second branch pipe 32 of the flow path switching units 3a and 3b corresponding to utilization units 1a and 1b. The refrigerant flowing out of the second branch pipe 32 flows to the corresponding utilization unit 1.

[0101] In utilization units 1a and 1b, the refrigerant condenses by dissipating heat to the air in the air-conditioned space within the heat exchanger 11. As a result, heating is performed on the air-conditioned space corresponding to utilization units 1a and 1b. The refrigerant, after condensation in the heat exchanger 11, passes through the expansion mechanism 13. Here, the expansion mechanism 13 adjusts its opening based on the subcooling of the refrigerant determined by a temperature sensor (not shown). The refrigerant flowing out of utilization units 1a and 1b converges in the liquid refrigerant connecting pipe 5.

[0102] The refrigerant, after converging in the liquid refrigerant connecting pipe 5, flows into the utilization unit 1c. The refrigerant flowing into the utilization unit 1c is depressurized to a low pressure upon passing through the utilization expansion mechanism 13, and then flows through the utilization heat exchanger 11. In the utilization heat exchanger 11, the refrigerant absorbs heat from the air in the air-conditioned space and evaporates. As a result, cooling is performed on the air-conditioned space corresponding to the utilization unit 1c. The refrigerant used for cooling the air-conditioned space in the utilization unit 1c passes through the first branch pipe 31 of the flow path switching unit 3c corresponding to the utilization unit 1c, then flows through the low-pressure gas refrigerant connecting pipe 6, is drawn into the compressor 21, and is compressed again.

[0103] (3-2-2) Second, simultaneous operation of hot and cold water

[0104] The second simultaneous heating and cooling operation refers to the operation of a refrigeration unit in which the number of utilization units 1 performing heating operation is less than the number of utilization units 1 performing cooling operation. The following explanation will use the case where utilization unit 1a performs heating operation and utilization units 1b and 1c perform cooling operation as an example.

[0105] In the second simultaneous heating and cooling operation, the first port 22a of the first three-way valve 22 is connected to the second port 22b, and the first port 23a of the second three-way valve 23 is connected to the second port 23b. Furthermore, in the flow path switching unit 3a corresponding to the utilization unit 1a operating in heating mode, the first shut-off valve 33 is closed, and the second shut-off valve 34 is open. Additionally, in the flow path switching units 3b and 3c corresponding to utilization units 1b and 1c, the first shut-off valve 33 is open, and the second shut-off valve 34 is closed.

[0106] When compressor 21 starts, the refrigerant discharged from compressor 21 is diverted to the first three-way valve 22 and the second three-way valve 23. The refrigerant after passing through the first three-way valve 22 condenses in the heat source heat exchanger 24, then passes through the heat source expansion mechanism 25 adjusted to a predetermined opening and flows through the liquid refrigerant connecting pipe 5. On the other hand, the refrigerant after passing through the second three-way valve 23 flows through the high-pressure gas refrigerant connecting pipe 7 and flows to the second branch pipe 32 of the flow path switching unit 3a corresponding to utilization unit 1a. The refrigerant flowing out of the second branch pipe 32 flows to the corresponding utilization unit 1.

[0107] In utilization unit 1a, the refrigerant condenses by dissipating heat to the air in the air-conditioned space within the utilization heat exchanger 11. As a result, heating is performed on the air-conditioned space corresponding to utilization unit 1a. The refrigerant condensed in the utilization heat exchanger 11 passes through the utilization expansion mechanism 13. Here, the opening of the utilization expansion mechanism 13 is adjusted based on the subcooling of the refrigerant obtained by a temperature sensor (not shown). The refrigerant flowing out of utilization unit 1a flows into the liquid refrigerant connecting pipe 5.

[0108] The refrigerant flowing to the liquid refrigerant connecting pipe 5 is diverted to utilization units 1b and 1c. This refrigerant is depressurized to a low pressure upon passing through the utilization expansion mechanism 13, and then flows through the utilization heat exchanger 11. In the utilization heat exchanger 11, the refrigerant absorbs heat from the air in the air-conditioned space and evaporates. As a result, cooling is performed on the air-conditioned space corresponding to utilization units 1b and 1c. The refrigerant used for cooling the air-conditioned space in utilization units 1b and 1c passes through the first branch pipe 31 of the flow path switching units 3b and 3c, then converges in the low-pressure gaseous refrigerant connecting pipe 6, is drawn into the compressor 21, and is compressed again.

[0109] (3-3) Control of refrigerant leakage

[0110] In the event of refrigerant leakage, the control unit 8 controls the various devices constituting the refrigeration cycle unit 100 in the manner described below.

[0111] If, during air conditioning operation, a refrigerant leak is detected in any of the multiple utilization units 1 (in other words, the refrigerant sensor 16 detects refrigerant), and the total capacity (rated capacity) of the utilization units 1 other than the utilization unit 1 where the refrigerant leak was detected is more than a predetermined ratio R of the capacity (rated capacity) of the first heat source unit 2, the control unit 8 performs first control.

[0112] In the first control, the control unit 8 blocks the flow of refrigerant to the utilization unit 1 that has detected a refrigerant leak by means of the flow path switching unit 3, and allows the operation of the utilization units 1 other than the utilization unit 1 that has detected a refrigerant leak to continue.

[0113] Furthermore, during air conditioning operation, if a refrigerant leak is detected in any of the multiple utilization units 1 (in other words, the refrigerant sensor 16 detects refrigerant), and the total capacity of the utilization units 1 other than the utilization unit 1 where the refrigerant leak was detected is less than a predetermined ratio R of the capacity (rated capacity) of the first heat source unit 2, the control unit 8 performs a second control.

[0114] In the second control, the control unit 8 blocks the flow of refrigerant to the utilization unit 1 that has detected a refrigerant leak through the flow path switching unit 3, and stops the operation of all utilization units 1, including the utilization unit 1 that has detected a refrigerant leak.

[0115] The specified ratio R is the ratio of the capacity of the utilization unit 1 (or the sum of the capacities of multiple utilization units 1 if there are multiple utilization units 1) to the capacity of the first heat source unit 2, which enables the first heat source unit 2 to ensure the refrigeration cycle device 100 can perform defrosting operation. The heat required for the refrigeration cycle device 100 to perform defrosting operation refers to the heat required by the heat source heat exchanger 24 to remove frost generated on the outer surface. In this embodiment, the specified ratio R is 50%.

[0116] Reference Figure 3 The flowchart below provides a detailed explanation of the refrigerant leak control measures. The refrigerant leak control begins simultaneously with the startup of the refrigeration cycle unit 100.

[0117] In step S10, the control unit 8 determines whether a refrigerant leak is detected in any of the multiple utilization units 1; specifically, it determines whether refrigerant is detected by the refrigerant sensor 16. If the control unit 8 determines that refrigerant has been detected (Yes), the process proceeds to step S11. If the control unit 8 does not determine that refrigerant has been detected (No), the process proceeds to step S10.

[0118] In step S11, the control unit 8 calculates the total capacity Pa of the utilization units 1 other than the utilization unit 1 that detected the refrigerant, and proceeds the process to step S12. Here, the total value Pa is a value calculated by summing the rated capacity (in horsepower, etc.) of the utilization units 1 other than the utilization unit 1 that detected the refrigerant.

[0119] The control unit 8 calculates the total value Pa by summing the rated capacities of the utilization units 1 other than the utilization unit 1 where refrigerant is detected.

[0120] In step S12, the control unit 8 determines whether the total value Pa is greater than or equal to a predetermined percentage R (50%) of the rated capacity Ps (in horsepower, etc.) of the first heat source unit 2. If the total value Pa is greater than or equal to the predetermined percentage R of the rated capacity Ps of the first heat source unit 2 (yes), the control unit 8 proceeds the process to step S13. If the total value Pa is not greater than or equal to the predetermined percentage R (50%) of the rated capacity Ps of the first heat source unit 2 (no), the control unit 8 proceeds the process to step S14.

[0121] In step S13, the control unit 8 performs a first control and a refrigerant leak control. In the first control, the control unit 8 blocks the flow of refrigerant to the utilization unit 1 where a refrigerant leak has been detected via the flow path switching unit 3. Specifically, the control unit 8 closes the first shut-off valve 33 and the second shut-off valve 34 of the flow path switching unit 3 corresponding to the utilization unit 1 where a refrigerant leak has been detected. Simultaneously, the control unit 8 allows the operation of the utilization units 1 other than the one where a refrigerant leak has been detected to continue.

[0122] For example, when the first control is initiated based on the refrigerant detection by the refrigerant sensor 16 of the utilization unit 1a, the control unit 8 closes the first shut-off valve 33a and the second shut-off valve 34a of the flow path switching unit 3a. At this time, the control unit 8 stops the operation of the utilization unit 1a. At the same time, the control unit 8 resumes the operation of the utilization units 1b and 1c.

[0123] In step S14, the control unit 8 performs a second control and terminates the refrigerant leak control. In the second control, the control unit 8 blocks the flow of refrigerant to the utilization unit 1 that detected the refrigerant leak via the flow path switching unit 3. Simultaneously, the control unit 8 stops the operation of all utilization units 1, including the utilization unit 1 that detected the refrigerant leak.

[0124] For example, when performing the second control based on the refrigerant detection by the refrigerant sensor 16 of the utilization unit 1a, the control unit 8 closes the first shut-off valve 33a and the second shut-off valve 34a of the flow path switching unit 3a. At the same time, the control unit 8 stops the operation of the utilization units 1a to 1c.

[0125] (4) Characteristics

[0126] (4-1)

[0127] The refrigeration cycle device 100 includes a first heat source unit 2, multiple utilization units 1, a flow path switching unit 3, and a control unit 8.

[0128] The flow path switching unit 3 is disposed between the first heat source unit 2 and the utilization unit 1, and switches the flow of refrigerant flowing between the first heat source unit 2 and the utilization unit 1. The control unit 8 controls the first heat source unit 2, the utilization unit 1 and the flow path switching unit 3.

[0129] During air conditioner operation, if a refrigerant leak is detected in any of the multiple utilization units 1, and the total capacity of the utilization units 1 other than the one where the refrigerant leak was detected is more than a predetermined proportion R of the capacity of the first heat source unit 2, the control unit 8 performs a first control. In the first control, the flow path switching unit 3 blocks the flow of refrigerant to the utilization unit 1 where the refrigerant leak was detected, and the operation of the utilization units 1 other than the one where the refrigerant leak was detected continues.

[0130] According to the refrigeration cycle device 100, even if the flow of refrigerant to the utilization unit 1 where a refrigerant leak has occurred is blocked, the operation of the remaining utilization unit 1 can continue. Therefore, even if a refrigerant leak is detected in the utilization unit 1 and the flow of refrigerant to the utilization unit is blocked, the refrigeration cycle device 100 can minimize the deterioration of the comfort of the air-conditioned space.

[0131] (4-2)

[0132] During air conditioner operation, if a refrigerant leak is detected in any of the multiple utilization units 1, and the total capacity of the utilization units 1 other than the one where the refrigerant leak was detected is less than a predetermined ratio R, the control unit 8 performs a second control. In the second control, the flow path switching unit 3 blocks the flow of refrigerant into the utilization unit 1 where the refrigerant leak was detected, and stops the operation of the utilization units other than the one where the refrigerant leak was detected.

[0133] The refrigeration circulation device 100 suppresses the decrease in comfort caused by the inability to maintain operation at the desired capacity.

[0134] (4-3)

[0135] Air conditioning operation includes defrosting operation. The specified ratio R is the ratio of the capacity of the first heat source unit 1 to the capacity of the first heat source unit 2, which enables the first heat source unit 2 to ensure the heat required for the refrigeration cycle unit 100 to perform defrosting operation.

[0136] By blocking the flow of refrigerant to the utilization unit 1 where a refrigerant leak has been detected, the total amount of heat absorbed in the utilization unit 1 (specifically, the utilization heat exchanger 11) is reduced compared to the case where refrigerant flows into all utilization units 1. As a result, during defrosting operation, defrosting may not be adequately performed due to insufficient heat dissipation in the heat source heat exchanger 24 (in other words, the refrigeration cycle unit 100 cannot perform defrosting operation).

[0137] In this embodiment, when the flow of refrigerant to the utilization unit 1 where a refrigerant leak has been detected is blocked, the control unit 8 determines, based on a predetermined ratio R, whether to continue operating the utilization units 1 other than the one where a refrigerant leak has been detected. Therefore, in the refrigeration cycle apparatus 100, even when the flow of refrigerant to the utilization unit 1 is blocked, defrosting operation is performed as long as the heat required by the first heat source unit 2 can be ensured.

[0138] Therefore, the refrigeration circulation unit 100 can perform defrosting operation while suppressing the deterioration of the comfort of the air-conditioned space when the inflow of refrigerant to the utilization unit 1 is blocked.

[0139] (5) Variations

[0140] (5-1) Variation A

[0141] When the air conditioner is in operation, including defrosting operation, the control unit 8 can also control the various devices constituting the refrigeration cycle unit 100 in the event of a refrigeration leak, as described below.

[0142] When the control unit 8 determines that there is no plan to perform defrosting operation, even if the air conditioner is in operation, if a refrigerant leak is detected in any of the multiple utilization units 1, and the total capacity of the utilization units 1 other than the utilization unit 1 in which the refrigerant leak was detected is less than a predetermined ratio R of the capacity of the heat source unit 2, the control unit 8 shall also perform the first control.

[0143] Reference Figure 4 The flowchart, to be consistent with Figure 3 The flowchart shown focuses on the differences in refrigerant leakage control in the refrigeration cycle unit 100 of Modified Example A, and will be explained in detail below. The explanations of steps already described will be omitted hereafter.

[0144] Figure 3 The flowchart shown is Figure 4 The main difference in the flowcharts shown is that, Figure 4 The flowchart shown includes step S15.

[0145] In step S12, the control unit 8 determines whether the total value Pa is greater than or equal to a predetermined percentage R (50%) of the rated capacity Ps of the first heat source unit 2. If the total value Pa is greater than or equal to the predetermined percentage R of the rated capacity Ps of the first heat source unit 2 (yes), the control unit 8 proceeds the process to step S13. If the total value Pa is not greater than or equal to the predetermined percentage R (50%) of the rated capacity Ps of the first heat source unit 2 (no), the control unit 8 proceeds the process to step S15.

[0146] In step S15, the control unit 8 determines whether the refrigeration cycle unit 100 plans to perform defrosting operation. If the control unit 8 determines that the refrigeration cycle unit 100 plans to perform defrosting operation (Yes), the process proceeds to step S14. If the control unit 8 does not determine that the refrigeration cycle unit 100 plans to perform defrosting operation (No), the process proceeds to step S13.

[0147] The determination of whether the refrigeration circulation unit 100 is scheduled to perform defrost operation is based, for example, on a setting indicating whether defrost operation should be performed. This setting is, for example, set by the user. During periods of relatively high temperature, such as summer, frost is rarely produced; therefore, users sometimes set defrost operation to not be required. In such cases, the control unit 8 determines that there is no plan to perform defrost operation. The setting for whether to perform defrost operation can also be based on the detection results of a temperature sensor and / or humidity sensor (not shown).

[0148] Even if the flow of refrigerant to the utilization unit 1 where a refrigerant leak has occurred is blocked when defrosting operation is not planned, there is no need to consider ensuring the heat required to perform defrosting operation. Therefore, in the refrigeration cycle device 100 of Modification A, the operation of the remaining utilization unit 1 continues even when defrosting operation is not planned. Even if a refrigerant leak is detected in utilization unit 1 and the flow of refrigerant to the utilization unit is blocked, the refrigeration cycle device 100 of Modification A can minimize the deterioration of the comfort of the air-conditioned space.

[0149] (5-2) Variation B

[0150] The control unit 8 can also, in the first control, adjust the target evaporation temperature Te or the target condensation temperature Tc in the utilization heat exchanger 11 of the utilization unit 1 that continues to operate, based on the capacity of the utilization unit 1 where the inflow of refrigerant has been blocked.

[0151] For example, the control unit 8 can reduce the target evaporation temperature Te in the utilization heat exchanger 11 of the utilization unit 1 that continues to operate, based on the rated capacity of the utilization unit 1 that was stopped in the first control. Furthermore, the control unit 8 can increase the target condensation temperature Te in the utilization heat exchanger 11 of the utilization unit 1 that continues to operate, based on the rated capacity of the utilization unit 1 that was stopped in the first control.

[0152] In the refrigeration cycle device 100 of Modified Example B, the continued operation of the utilization unit 1 compensates for the reduced output of the utilization unit 1 that has stopped operating due to the blockage of refrigerant inflow. Therefore, the deterioration of the comfort of the air-conditioned space can be minimized.

[0153] (5-3) Variation C

[0154] The control unit 8 can also perform protective control based on the capacity of the utilization unit 1, where the refrigerant inflow is blocked, in the first control. Protective control refers to the control that protects the equipment constituting the refrigeration cycle device 100 from the effect of a temporary increase in refrigerant pressure in the refrigerant circuit 9 caused by the blockage of refrigerant inflow in a part of the utilization unit 1.

[0155] For example, the control unit 8 can reduce the maximum speed of the compressor 21 to below the normal value during the first control period as a protective control.

[0156] The refrigeration cycle device 100 of Modified Example C can suppress equipment damage caused by the execution of the first control.

[0157] (5-4) Variation D

[0158] The refrigeration cycle device 100 may also include a second heat source unit 2a, and during the first control, the second heat source unit 2a compensates for the operation of the capacity of the utilization unit 1 when a refrigerant leak is detected.

[0159] like Figure 5 As shown, the refrigeration cycle apparatus 100 of Modified Example D further includes a second heat source unit 2a. A flow path switching unit 3 is also provided between the second heat source unit 2a and the plurality of utilization units 1, switching the flow of refrigerant between the second heat source unit 2a and the plurality of utilization units 1. During the first control operation, the control unit 8 causes the second heat source unit 2a to compensate for the capacity of the utilization units 1 whose refrigerant inflow has been blocked.

[0160] Specifically, during the first control period, the control unit 8 refers to the rated capacity of each utilization unit 1 stored in the storage device and causes the second heat source unit 2a to operate at the rated capacity of the utilization unit 1 whose refrigerant inflow has been blocked.

[0161] In the refrigeration cycle device 100 of Modification D, in the first control, the second heat source unit 2a compensates for the reduced output of the utilization unit when the refrigerant inflow is blocked and the operation is stopped. Therefore, the deterioration of the comfort of the air-conditioned space can be minimized.

[0162] (5-5) Variation E

[0163] The form of the flow path switching unit 3 is not limited to a separate type in which each corresponding utilization unit 1 is set in a different position. The flow path switching unit 3 can also be a collection type in which the first branch pipe 31, the second branch pipe 32, the first flow interruption valve 33 and the second flow interruption valve 34 of multiple flow path switching units 3 are housed in a single housing.

[0164] (5-6) Variation F

[0165] The specified ratio R can also be a value other than 50%. In addition, the specified ratio R can also be calculated based on a value other than the ratio of the total capacity of the utilization units 1 required for the refrigeration cycle unit 100 to perform defrost operation to the capacity of the first heat source unit 2.

[0166] <Conclusion>

[0167] The embodiments of this disclosure have been described above. However, it should be understood that various changes in form and detail can be made without departing from the spirit and scope of this disclosure as set forth in the claims.

[0168] Symbol Explanation

[0169] 1, 1a, 1b, 1c utilize units; 2. First heat source unit; 2a Second heat source unit; 3, 3a, 3b, 3c Flow path switching units; 8. Control Department; 11, 11a, 11b, 11c utilize heat exchangers; 100 Refrigeration circulation unit; Tc is the target condensation temperature. Te is the target evaporation temperature; R specifies the ratio.

[0170] Existing technical documents

[0171] Patent documents

[0172] Patent document 1: International Publication No. 2016 / 129027.

Claims

1. A refrigeration circulation device (100), wherein the refrigeration circulation device performs air conditioning operation, characterized in that, include: First heat source unit (2); Multiple utilization units (1, 1a, 1b, 1c); A flow path switching unit (3) is disposed between the first heat source unit and the utilization unit to switch the flow of refrigerant flowing between the first heat source unit and the utilization unit; and Control unit (8) controls the first heat source unit, the utilization unit, and the flow path switching unit. During the operation of the air conditioner, if a refrigerant leak is detected in any of the plurality of utilization units, and the total capacity of the utilization units other than the one in which the refrigerant leak was detected is a predetermined proportion (R) or more of the capacity of the first heat source unit, The control unit performs a first control, in which the flow path switching unit blocks the flow of refrigerant into the utilization unit that has detected a refrigerant leak, and allows the operation of the utilization units other than the utilization unit that has detected a refrigerant leak to continue.

2. The refrigeration cycle apparatus according to claim 1, characterized in that, During the operation of the air conditioner, if a refrigerant leak is detected in any of the plurality of utilization units, and the total capacity of the utilization units other than the one in which the refrigerant leak was detected is less than the predetermined proportion of the capacity of the first heat source unit, The control unit performs a second control, in which the flow path switching unit blocks the flow of refrigerant into the utilization unit that has detected a refrigerant leak, and stops the operation of the utilization units other than the utilization unit that has detected a refrigerant leak.

3. The refrigeration cycle apparatus according to claim 1 or 2, characterized in that, The air conditioner operation includes defrosting operation. The specified ratio is the ratio of the capacity of the utilization unit to the capacity of the first heat source unit, which enables the first heat source unit to ensure the heat required to perform the defrosting operation.

4. The refrigeration cycle apparatus according to claim 3, characterized in that, When the control unit determines that there is no plan to perform the defrosting operation. During the operation of the air conditioner, even if a refrigerant leak is detected in any of the plurality of utilization units, and the total capacity of the utilization units other than the one where the refrigerant leak was detected is less than the predetermined proportion of the capacity of the first heat source unit, The control unit also performs the first control.

5. The refrigeration cycle apparatus according to any one of claims 1 to 4, characterized in that, The utilization unit includes a heat exchanger (11, 11a, 11b, 11c). In the first control, the control unit adjusts the target evaporation temperature (Te) or target condensation temperature (Tc) in the utilization heat exchanger of the utilization unit that continues to operate, based on the capacity of the utilization unit where the inflow of the refrigerant has been blocked.

6. The refrigeration cycle apparatus according to any one of claims 1 to 5, characterized in that, In the first control, the control unit performs protective control based on the capacity of the utilization unit where the inflow of the refrigerant has been blocked.

7. The refrigeration cycle apparatus according to any one of claims 1 to 6, characterized in that, The refrigeration cycle device also includes a second heat source unit (2a). The flow path switching unit is also disposed between the second heat source unit and the plurality of utilization units, and switches the flow of the refrigerant flowing between the second heat source unit and the plurality of utilization units. When the control unit performs the first control, it causes the second heat source unit to operate to compensate for the capacity of the utilization unit, which has had its refrigerant inflow blocked.

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