Refrigeration cycle device

Abstract

To provide a refrigeration cycle device enabling suppression of discomfort of a user caused by fluid sound of a refrigerant in an indoor unit during operation stop in pressure equalization control.SOLUTION: A refrigeration cycle device includes a primary refrigerant circuit in which a primary refrigerant is circulated, and a control device. The primary refrigerant circuit includes: an outdoor unit having a compressor and an outdoor heat exchanger; at least one first indoor unit having a refrigerant heat exchanger and a first expansion valve; and at least one relay unit having a water refrigerant heat exchanger performing heat exchange between the refrigerant and water, and a second expansion valve, and connected to the outdoor unit in parallel to the first indoor unit. The control device controls the compressor, the first expansion valve and the second expansion valve. The control device performs control in such a way that the opening of the second expansion valve becomes equal to or more than a preset first predetermined opening when the compressor is stopped.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a refrigeration cycle apparatus including a relay unit that connects a refrigerant circuit and a water circuit. [Background technology]

[0002] There is known an air conditioner that includes a refrigerant circuit having a compressor and an outdoor heat exchanger that circulates a refrigerant, a water circuit having a water-refrigerant heat exchanger and a pump that circulates water that exchanges heat with the refrigerant, and a plurality of indoor units connected to the water circuit or the water circuit and the refrigerant circuit. This type of air conditioner includes a plurality of indoor expansion valves provided corresponding to the plurality of indoor units, and the opening degree of each indoor expansion valve is controlled according to the required capacity of the indoor unit, and the indoor expansion valve corresponding to the indoor unit that has the thermostat turned off is controlled to be fully closed or slightly open (for example, see Patent Document 1).

[0003] Furthermore, in this type of air conditioner, the compressor cannot start if the pressure difference between high and low pressures is large. Specifically, the compressor has a lower limit for the suction side pressure and an upper limit for the discharge side pressure according to the rotation speed as a specification, and operating the compressor under conditions outside this range can deteriorate reliability. For this reason, when the compressor stops, pressure equalization control is performed to increase the opening of the expansion valve to eliminate the pressure difference between the indoor unit and the outdoor unit (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-132357 [Patent Document 2] JP 2006-46692 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the opening degree of the expansion valve is increased to perform pressure equalization control, a large flow rate of refrigerant will flow into the indoor unit that has been stopped due to thermo-off or the like, and the noise of this refrigerant flowing may cause discomfort to users in the room where the indoor unit is installed.

[0006] In view of the above circumstances, an object of the present invention is to provide a refrigeration cycle device that can suppress the discomfort felt by a user caused by the flow noise of a refrigerant in an indoor unit when operation is stopped during pressure equalization control. [Means for solving the problem]

[0007] A refrigeration cycle device according to one embodiment of the present invention comprises: a primary refrigerant circuit including an outdoor unit having a compressor and an outdoor heat exchanger, at least one first indoor unit having a refrigerant heat exchanger and a first expansion valve, and at least one relay unit having a water-refrigerant heat exchanger for exchanging heat between a refrigerant and water and a second expansion valve, the relay unit being connected to the outdoor unit in parallel with the first indoor unit, and in which a primary refrigerant circulates; a control device that controls the compressor, the first expansion valve, and the second expansion valve, When the compressor is stopped, the control device controls the opening degree of the second expansion valve to an opening degree equal to or greater than a first predetermined opening degree that is set in advance.

[0008] The control device may control the opening degree of the second expansion valve to the first predetermined opening degree when the opening degree of the second expansion valve when the compressor is stopped is less than the first predetermined opening degree.

[0009] The control device may maintain the opening degree of the second expansion valve at an opening degree equal to or greater than the first predetermined opening degree when the compressor is stopped.

[0010] The water-refrigerant heat exchanger is connected to a secondary refrigerant circuit including a second indoor unit having a water heat exchanger and a circulation pump, through which a secondary refrigerant circulates; The relay unit includes: a primary refrigerant temperature detection unit that detects a temperature of the primary refrigerant flowing into the water-refrigerant heat exchanger; a secondary refrigerant temperature detection unit that detects the temperature of the secondary refrigerant flowing into the water-refrigerant heat exchanger, The control device may operate the circulating pump when the compressor is stopped in an operating state in which the relay unit functions as a condenser and the detection value of the primary refrigerant temperature detection unit is higher than the detection value of the secondary refrigerant temperature detection unit.

[0011] Alternatively, the water-refrigerant heat exchanger is connected to a secondary refrigerant circuit including a second indoor unit having a water heat exchanger and a circulation pump, through which a secondary refrigerant circulates, The relay unit includes: a primary refrigerant temperature detection unit that detects a temperature of the primary refrigerant flowing into the water-refrigerant heat exchanger; a secondary refrigerant temperature detection unit that detects the temperature of the secondary refrigerant flowing into the water-refrigerant heat exchanger, The control device may operate the circulating pump when the compressor is stopped in an operating state in which the relay unit functions as an evaporator and the detection value of the primary refrigerant temperature detection unit is lower than the detection value of the secondary refrigerant temperature detection unit.

[0012] The first predetermined opening degree may be set according to a proportion of an internal volume of the primary refrigerant in the water-refrigerant heat exchanger to a total internal volume of the primary refrigerant circuit, and may be set to a smaller opening degree as the proportion increases.

[0013] The control device may also control the opening degree of the first expansion valve to a second predetermined opening degree, which is an opening degree corresponding to a flow rate smaller than the flow rate of the primary refrigerant corresponding to the first predetermined opening degree, when the compressor stops with the second expansion valve fully closed. Effect of the Invention

[0014] According to the present invention, it is possible to suppress discomfort felt by a user due to the flow noise of the refrigerant in an indoor unit that is not operating during pressure equalization control. [Brief description of the drawings]

[0015] [Figure 1] 1 is a refrigerant-water circuit diagram of a refrigeration cycle device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a configuration of a control device in the refrigeration cycle device. [Diagram 3] 5 is a flowchart showing an example of a processing procedure executed in the control device. [Figure 4] 5 is a flowchart showing a processing procedure of pressure equalization control according to a first control example. [Diagram 5] 10 is a flowchart showing a procedure for pressure equalization control according to a second control example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] [Refrigeration cycle equipment configuration] 1 is a refrigerant-water circuit diagram of a refrigeration cycle apparatus 100 according to one embodiment of the present invention. The refrigeration cycle apparatus 100 of this embodiment is an air conditioner, and includes an outdoor unit 2, a plurality (two in this embodiment) of first indoor units 3a, 3b (hereinafter also referred to as the first indoor units 3 unless otherwise described), a plurality (two in this embodiment) of relay units 50a, 50b (hereinafter referred to as the relay units 50 unless otherwise described), and a control device 90.

[0018] (Outdoor unit) The outdoor unit 2 has a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor expansion valve 24, and an accumulator 25. By connecting each of these devices to the first indoor unit 3 and the relay unit 50 in parallel with piping, a primary refrigerant circuit 20 is formed in which a refrigerant (primary refrigerant) circulates in the refrigerant-water circuit of the refrigeration cycle apparatus 100.

[0019] The compressor 21 is a variable displacement compressor whose operating capacity can be changed by controlling the rotation speed by an inverter (not shown). The refrigerant discharge side of the compressor 21 is connected to the port a of the four-way valve 22 by a discharge pipe 61. The refrigerant suction side of the compressor 21 is connected to the refrigerant outflow side of the accumulator 25 by a suction pipe 65.

[0020] The four-way valve 22 is a valve for switching the flow direction of the refrigerant, and has four ports a, b, c, and d. As described above, the port a is connected to the refrigerant discharge side of the compressor 21 by the discharge pipe 61. The port b is connected to one of the refrigerant inlets and outlets of the outdoor heat exchanger 23 by the refrigerant piping 62. The port c is connected to the refrigerant inlet side of the accumulator 25 by the refrigerant piping 66. The port d is connected to the gas refrigerant inlet and outlet 51b of the water-refrigerant heat exchanger 51 in the relay unit 50 and one of the refrigerant inlets and outlets of the indoor heat exchanger 31 in the indoor unit 3 by the outdoor unit gas pipe 64, the gas branch pipe 17, and the gas pipe 37.

[0021] The outdoor heat exchanger 23 exchanges heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29. One refrigerant inlet / outlet of the outdoor heat exchanger 23 is connected to the port b of the four-way valve 22 by the refrigerant piping 62 as described above, and the other refrigerant inlet / outlet is connected to the liquid refrigerant inlet / outlet 51a of the water-refrigerant heat exchanger 51 in the relay unit 50, and to the first expansion valve 33 in the first indoor unit 3, the outdoor unit liquid pipe 63, and the liquid branch pipe 16.

[0022] The outdoor expansion valve 24 is, for example, an electronic expansion valve. The outdoor expansion valve 24 is disposed in the outdoor unit liquid pipe 63, and its opening degree can be adjusted to reduce the pressure of the refrigerant passing therethrough.

[0023] The outdoor fan 29 is made of resin, and is disposed near the outdoor heat exchanger 23. The outdoor fan 29 is rotated by a fan motor (not shown) to take in outside air from an intake port (not shown) of the outdoor unit 2 into the interior of the outdoor unit 2, and discharges the outside air that has exchanged heat with the refrigerant in the outdoor heat exchanger 23 to the outside of the outdoor unit 2 from an outlet port (not shown) of the outdoor unit 2.

[0024] (1st indoor unit) The first indoor unit 3 has an indoor heat exchanger 31, an indoor fan 32, and a first expansion valve (indoor expansion valve) 33. In Fig. 1, the first indoor unit 3 has two first indoor units 3a, 3b connected in parallel. Each of the first indoor units 3a, 3b has the same configuration, and is connected to the outdoor unit 2 to form a refrigerant circuit 20 in the refrigerant-water circuit of the refrigeration cycle apparatus 100. The number of first indoor units 3 is not limited to two, and may be at least one.

[0025] The indoor heat exchanger 31 is a refrigerant heat exchanger in which heat is exchanged between the refrigerant and the outside air taken into the first indoor unit 3 by the rotation of the indoor fan 32. The outdoor unit liquid pipe 63 and the first indoor unit 3 are connected by a liquid pipe 36, and the liquid pipe 36 and one of the refrigerant inlet and outlets of the indoor heat exchanger 31 are connected by an indoor unit liquid pipe 38. The outdoor unit gas pipe 64 and the first indoor unit 3 are connected by a gas pipe 37, and the gas pipe 37 and the other refrigerant inlet and outlet of the indoor heat exchanger 31 are connected by an indoor unit gas pipe 39.

[0026] The first expansion valve 33 is, for example, an electronic expansion valve. The first expansion valve 43 is disposed in the indoor unit liquid pipe 38, and its opening degree can be adjusted to reduce the pressure of the refrigerant passing therethrough.

[0027] The indoor fan 32 is made of resin and is disposed near the indoor heat exchanger 31. The indoor fan 32 is driven by a fan motor (not shown), takes in indoor air from an intake port (not shown) of the first indoor unit 3, and releases the air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 from an outlet port (not shown) of the first indoor unit 3 into the room.

[0028] (Relay unit) The relay unit 50 has a water-refrigerant heat exchanger 51 and a second expansion valve 52. In Fig. 1, the relay unit 50 has two relay units 50a, 50b connected in parallel. The relay units 50a, 50b are connected to the outdoor unit 2 in parallel with the first indoor unit 3. The relay unit 50 is installed outdoors as a separate unit from the outdoor unit 2, but may be installed inside the outdoor unit 2. The number of relay units 50 is not limited to a plurality, and it is sufficient that there is at least one.

[0029] The water-refrigerant heat exchanger 51 is, for example, a double-pipe heat exchanger and has a refrigerant side flow path 511, a water side flow path 512, a liquid refrigerant inlet / outlet 51a connected to the liquid pipe 36, a gas refrigerant inlet / outlet 51b connected to the gas pipe 37, a water inlet 51c, and a water outlet 51d.

[0030] The refrigerant-side flow path 511 has one end connected to the liquid refrigerant inlet / outlet 51a and the other end connected to the gas refrigerant inlet / outlet 51b. The water-side flow path 512 has one end connected to the water inlet 51c and the other end connected to the water outlet 51d. In the water-refrigerant heat exchanger 51, the refrigerant flowing through the refrigerant-side flow path 511 exchanges heat with the water flowing through the water-side flow path 512.

[0031] The liquid refrigerant inlet / outlet 51a is connected to the other refrigerant inlet / outlet of the outdoor heat exchanger 23 by the liquid branch pipe 16 and the outdoor unit liquid pipe 63. The liquid branch pipe 16 is a refrigerant piping branching off from the liquid pipe 36. The gas refrigerant inlet / outlet 51b is connected to the port d of the four-way valve 22 by the gas branch pipe 17 and the outdoor unit gas pipe 64. The gas branch pipe 17 is a refrigerant piping branching off from the gas pipe 37. The water inlet 51c is connected to the indoor heat exchanger 41 of the second indoor unit 4 by the second water pipe 12. The water outlet 51d is connected to the indoor heat exchanger 41 of the second indoor unit 4 by the first water pipe 11.

[0032] The second expansion valve 52 is, for example, an electronic expansion valve. The second expansion valve 43 is disposed between the outdoor expansion valve 24 and the liquid refrigerant inlet / outlet 51a, and its opening degree can be adjusted to reduce the pressure of the refrigerant passing through it.

[0033] (Secondary refrigerant circuit) The water-refrigerant heat exchanger 51 is connected to secondary refrigerant circuits 40a, 40b in which water, which is a secondary refrigerant, circulates. The secondary refrigerant circuit 40a has a second indoor unit 4a connected to the water-refrigerant heat exchanger 51 of the relay unit 50a, and the secondary refrigerant circuit 40b has a second indoor unit 4b connected to the water-refrigerant heat exchanger 51 of the relay unit 50b.

[0034] In addition, since the secondary refrigerant circuits 40a, 40b have the same configuration, except when they are individually described below, the secondary refrigerant circuits 40a, 40b are collectively referred to as the secondary refrigerant circuit 40. Similarly, since the second indoor units 4a, 4b have the same configuration, except when they are individually described below, the second indoor units 4a, 4b are collectively referred to as the second indoor unit 4.

[0035] The secondary refrigerant circuit 40 includes a second indoor unit 4 and a circulation pump 44. The second indoor unit 4 has an indoor heat exchanger 41, an indoor fan 42, and an on-off valve 43.

[0036] The indoor heat exchanger 41 is a water-air heat exchanger that exchanges heat between water and the outside air taken into the second indoor unit 4 by the rotation of the indoor fan 42. The inlet side of the indoor heat exchanger 41 is connected to the water outlet 51d of the water-refrigerant heat exchanger 51 by the first water piping 11 and the first water piping 11. The outlet side of the indoor heat exchanger 41 is connected to the water inlet 51c of the water-refrigerant heat exchanger 51 by the second water piping 12.

[0037] The indoor fan 42 is made of resin, and is disposed near the indoor heat exchanger 41. The indoor fan 42 is rotated by a fan motor (not shown) to take in indoor air from an inlet (not shown) of the second indoor unit 4 into the second indoor unit 4, and blows the air that has exchanged heat with water in the indoor heat exchanger 41 out into the room from an outlet (not shown) of the second indoor unit 4. The indoor fan 42 and the indoor heat exchanger 41 constitute a fan coil unit (FCU).

[0038] The on-off valve 43 is disposed in the first water piping 11, and is a shutoff valve capable of shutting off the flow of water from the water outlet 51d of the water-refrigerant heat exchanger 51 toward the indoor heat exchanger 41. The opening and closing of the on-off valve 43 is controlled individually for each of the second indoor units 4a, 4b, and the on-off valve 43 of the second indoor unit 4 that is not operating (or is to be stopped) is switched to a closed state.

[0039] Note that a flow control valve whose opening degree can be adjusted arbitrarily may be used instead of the on-off valve 43. In this case, the flow rate of water flowing through the indoor heat exchanger 41 can be controlled according to the opening degree of the flow control valve. This makes it possible to adjust the flow rate of water flowing into the indoor heat exchanger 41 in cases where, for example, the capacity required by the second indoor unit 4 is exceeded even when the circulation pump 44 is driven at the minimum rotation speed, improving the ability to follow the required capacity and increasing comfort.

[0040] The circulation pump 44 is a variable capacity pump driven by a motor (not shown). When the circulation pump 44 is driven, water flows out from the water outlet 51d of the water-refrigerant heat exchanger 51 to the first water pipe 11, and circulates so that water flows into the water inlet 51c of the water-refrigerant heat exchanger 51 via the indoor heat exchanger 41 and the second water pipe 12.

[0041] The flow rate of water circulated by driving the circulation pump 44 is controlled by the rotation speed of the motor. This allows water to be supplied at the same flow rate to each second indoor unit 4. In the example shown in Fig. 1, the circulation pump 44 is disposed in the second water piping 12, but instead, it may be disposed in the first water piping 11, or may be disposed inside the relay unit 50.

[0042] (Sensors) Various sensors are provided in the refrigeration cycle apparatus 100. In the outdoor unit 2, the discharge pipe 61 is provided with a high-pressure sensor 71 that detects the pressure of the refrigerant discharged from the compressor 21, and a discharge temperature sensor 72 that detects the temperature of the refrigerant discharged from the compressor 21. The suction pipe 65 is provided with a low-pressure sensor 73 that detects the pressure of the refrigerant sucked into the compressor 21, and a suction temperature sensor 74 that detects the temperature of the refrigerant sucked into the compressor 21.

[0043] The outdoor heat exchanger 23 is provided with a heat exchanger temperature sensor 75 for detecting the temperature of the refrigerant flowing through the outdoor heat exchanger 23. An outdoor air temperature sensor 76 for detecting the temperature of the outdoor air flowing into the outdoor unit 2, i.e., the outdoor air temperature, is provided near an air inlet (not shown) of the outdoor unit 2. The first indoor unit 3 and the second indoor unit 4 are provided with a room temperature sensor 77 for detecting the temperature of the air flowing into the first indoor unit 3 and the second indoor unit 4 (room temperature).

[0044] A first refrigerant temperature sensor 78 is provided between the second expansion valve 55 and the liquid refrigerant inlet / outlet 51a in the liquid branch pipe 16 of the relay unit 50 to detect the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 during cooling operation, and a second refrigerant temperature sensor 79 is provided in the gas branch pipe 17 to detect the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 during heating operation. A water temperature sensor 80 is provided in the second water pipe 12 connected to the water inlet 51c of the water-refrigerant heat exchanger 51 to detect the temperature of the water flowing into the water-refrigerant heat exchanger 51. The first refrigerant temperature sensor 78 and the second refrigerant temperature sensor 79 correspond to a primary refrigerant temperature detection unit that detects the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51. The water temperature sensor 80 corresponds to a secondary refrigerant temperature detection unit that detects the temperature of the water flowing into the water-refrigerant heat exchanger 51.

[0045] (Control device) The control device 90 is, for example, an outdoor unit control device provided in the outdoor unit 2, and is mounted on a control board housed in an electrical component box (not shown) of the outdoor unit 2.

[0046] 2 is a block diagram showing the configuration of the control device 90. As shown in the figure, the control device 90 has a CPU 91, a storage unit 92, a communication unit 93, a sensor input unit 94, and a rotation speed detection unit 95.

[0047] The memory unit 92 is a non-volatile memory such as a flash memory, and stores the control program and control parameters of the outdoor unit 2, detection values ​​corresponding to detection signals from various sensors, the control states of the compressor 21 and the outdoor fan 29 etc., the rotation speed of the indoor fan 77 acquired via the communication unit 93, the control states of the first indoor unit 3 and the second indoor unit 4 including the operation mode set and input by the user, etc.

[0048] The communication unit 93 is an interface that communicates with the first indoor unit 3, the second indoor unit 4, and the relay unit 50. The sensor input unit 94 takes in detection results from various sensors in the outdoor unit 2 and outputs them to the CPU 91. The rotation speed detection unit 95 detects the rotation speed of the motor of the compressor 21 and outputs it to the CPU 91. The rotation speed detection unit 95 may be configured to directly detect the rotation speed of the motor using an encoder or the like attached to the drive shaft of the motor, or may be configured to detect the rotation speed of the motor from the drive current supplied to the motor. In the following description, the rotation speed of the compressor 21 refers to the rotation speed of the motor.

[0049] The CPU 91 is a control unit that controls the operation of each part of the outdoor unit 2, including the compressor 21, by executing a program stored in the storage unit 92. The program is installed in the control device 90 via, for example, various storage media. Alternatively, the program may be installed via the Internet or the like.

[0050] The CPU 91 takes in the detection results of each sensor of the outdoor unit 2 described above via the sensor input unit 94. Furthermore, the CPU 91 takes in the control signals transmitted from the first indoor unit 3 and the second indoor unit 4 via the communication unit 93. The control signals transmitted from the first indoor unit 3 and the second indoor unit 4 include the necessary operating capacity required by the first indoor unit 3 and the second indoor unit 4 (the total of the heat loads of the first indoor units 3a, 3b and the second indoor units 4a, 4b). Based on the taken-in detection results and control signals, the CPU 91 controls the drive of the compressor 21, the outdoor fan 29, the indoor fans 32, 42, and the circulation pump 44, for example, setting the indicated rotation speed which is the rotation speed at which these are driven. Furthermore, the CPU 91 controls the switching of the four-way valve 22 based on the taken-in detection results and control signals. Furthermore, the CPU 91 controls the opening degrees of the outdoor expansion valve 24, the first expansion valve 33, and the second expansion valve 52, and controls the opening and closing of the on-off valve 43, based on the captured detection results and control signals.

[0051] [Basic operation of refrigeration cycle equipment] Next, a description will be given of a basic operation of the refrigeration cycle apparatus 100. The operation of the refrigeration cycle apparatus 100 during cooling operation and heating operation will be described below.

[0052] (Cooling operation) When the refrigeration cycle apparatus 100 performs cooling operation (cooling operation mode), the four-way valve 22 is switched to the state shown by solid lines in Fig. 1, i.e., the state where port a and port b are communicated and port c and port d are communicated, and drives the compressor 21 and the circulation pump 44. Driving the compressor 21 causes the refrigerant to circulate through the refrigerant circuit 20, and driving the circulation pump 44 causes the water to circulate through the water circuit 40. As a result, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchanger 31 and the water-refrigerant heat exchanger 51 function as evaporators.

[0053] The rotation speed of the compressor 21 and the flow rate of the circulation pump 44 are determined according to the required operating capacity required by the second indoor unit 4. Here, an example will be described in which all indoor units (the first indoor unit 3, the second indoor unit 4) perform indoor cooling.

[0054] The refrigerant compressed by the compressor 21 to a high temperature and high pressure is discharged from the compressor 21, flows through the discharge pipe 61, and flows into the four-way valve 22, and then flows from the four-way valve 22 into the refrigerant piping 62 and into the outdoor heat exchanger 23. The refrigerant that has flowed into the outdoor heat exchanger 23 exchanges heat with outside air that has been drawn into the outdoor unit 2 by the rotation of the outdoor fan 29, and is condensed.

[0055] The refrigerant flowing out from the outdoor heat exchanger 23 flows through the outdoor unit liquid pipe 63 and passes through the outdoor expansion valve 24. A part of the refrigerant that has passed through the outdoor expansion valve 24 is decompressed when it flows through the liquid pipe 36 and passes through the first expansion valve 33, and the other part of the refrigerant that has passed through the outdoor expansion valve 24 is decompressed when it flows through the liquid branch pipe 16 and passes through the second expansion valve 52.

[0056] Here, the opening degree of the outdoor expansion valve 24 is, for example, fully open. The opening degree of the first expansion valve 33 is set to an evaporation pressure corresponding to the evaporation temperature in the first indoor heat exchanger 31, more specifically, lower than the minimum value (for example, 18°C) of the air conditioning temperature (set temperature) set in the first indoor unit 3. The opening degree of the second expansion valve 52 is set to an evaporation pressure corresponding to the evaporation temperature in the water-refrigerant heat exchanger 51 to realize the set temperature during cooling operation in the room where the second indoor unit 4 is installed, more specifically, the opening degree is set to an evaporation temperature in the water-refrigerant heat exchanger 51 and the temperature of the water flowing out from the water-refrigerant heat exchanger 51 are lower than the minimum value (for example, 18°C) of the air conditioning temperature (set temperature) set in the second indoor unit 4.

[0057] The refrigerant that has passed through the first expansion valve 33 flows into the indoor heat exchanger 31 via the indoor unit liquid pipe 38. The refrigerant that has flowed into the indoor heat exchanger 31 exchanges heat with indoor air that has been drawn into the inside of the first indoor unit 3 by the rotation of the indoor fan 32 and evaporates, thereby cooling the room in which the first indoor unit 3 is installed. The refrigerant that has flowed out of the indoor heat exchanger 31 flows into the outdoor unit gas pipe 64 via the indoor unit gas pipe 39 and the gas pipe 37, and returns to the compressor 21.

[0058] The refrigerant that has passed through the second expansion valve 52 flows into the liquid refrigerant inlet / outlet 51a of the water-refrigerant heat exchanger 51 via the liquid branch pipe 16. The refrigerant that has flowed into the liquid refrigerant inlet / outlet 51a passes through the refrigerant side flow path 511, exchanges heat with water flowing through the water side flow path 512, and evaporates, and flows from the gas refrigerant inlet / outlet 51b of the water-refrigerant heat exchanger 51 through the gas branch pipe 17 into the outdoor unit gas pipe 64. The refrigerant that has flowed into the outdoor unit gas pipe 64 flows through the four-way valve 22, refrigerant piping 66, accumulator 25, and suction pipe 65, and is sucked into the compressor 21 and compressed again.

[0059] On the other hand, the water cooled while flowing through the water-side flow path 512 flows into the first water piping 11 from the water outlet 51d of the water-refrigerant heat exchanger 51. The water that flows into the first water piping 11 flows into the indoor heat exchanger 41 of the second indoor unit 4 via the open on-off valve 43, and cools the indoor air passing through the indoor heat exchanger 41 by the rotation of the indoor fan 42. This cools the room in which the second indoor unit 4 is installed.

[0060] The water flowing out from the indoor heat exchanger 41 of each second indoor unit 4 is sucked into the circulation pump 44 via the second water piping 12. The water sucked into the circulation pump 44 is sent to the water inlet 51c of the water-refrigerant heat exchanger 51, passes through the water-side flow path 512, and is cooled again by the refrigerant flowing in the refrigerant-side flow path 511, and then flows out from the water outlet 51d toward the second indoor unit 4.

[0061] (Heating operation) When the refrigeration cycle apparatus 100 performs heating operation (heating operation mode), the four-way valve 22 is switched to the state shown by the dashed lines in Fig. 1, i.e., the state where port a communicates with port d and port b communicates with port c, and drives the compressor 21 and the circulation pump 44. Driving the compressor 21 causes the refrigerant to circulate through the refrigerant circuit 20, and driving the circulation pump 44 causes the water to circulate through the water circuit 40. As a result, the outdoor heat exchanger 23 functions as an evaporator, and the water-refrigerant heat exchanger 51 functions as a condenser.

[0062] The rotation speed of the compressor 21 and the flow rate of the circulation pump 44 are determined according to the required operating capacity required by the second indoor unit 4. Here, an example will be described in which all the indoor units (the first indoor unit 3, the second indoor unit 4) perform indoor heating.

[0063] The refrigerant compressed by the compressor 21 to become high temperature and high pressure is discharged from the compressor 21, flows through the discharge pipe 61 and flows into the four-way valve 22, and flows from the four-way valve 22 through the outdoor unit gas pipe 64 into the gas pipe 37 and the gas branch pipe 17.

[0064] The refrigerant that has flowed into the gas pipe 37 flows into the indoor heat exchanger 31 via the indoor unit gas pipe 39. The refrigerant that has flowed into the indoor heat exchanger 31 exchanges heat with indoor air that has been drawn into the inside of the first indoor unit 3 by the rotation of the indoor fan 32 and condenses, thereby heating the room in which the first indoor unit 3 is installed. The refrigerant that has flowed out of the indoor heat exchanger 31 is decompressed by the first expansion valve 33, and flows into the outdoor unit liquid pipe 63 via the indoor unit liquid pipe 38 and liquid pipe 36.

[0065] At this time, the opening degree of the first expansion valve 33 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out of the indoor heat exchanger 31 becomes the target subcooling, and more specifically, the opening degree is set so that the refrigerant flowing into the first expansion valve 33 becomes a single-phase liquid refrigerant that has been completely condensed in the indoor heat exchanger 31.

[0066] On the other hand, the refrigerant that has flowed into the gas refrigerant inlet / outlet 51b of the water-refrigerant heat exchanger 51. The refrigerant that has flowed into the gas refrigerant inlet / outlet 51b passes through the refrigerant-side flow path 511 and heats the water flowing through the water-side flow path 512. The refrigerant condensed by heat exchange with the water flowing through the water-side flow path 512 flows out from the liquid-side inlet / outlet 51a of the water-refrigerant heat exchanger 51 to the liquid branch pipe 16, is depressurized by the second expansion valve 52, and flows into the outdoor unit liquid pipe 63.

[0067] At this time, the opening degree of the second expansion valve 52 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out of the water-refrigerant heat exchanger 51 becomes a target subcooling in order to achieve the set temperature during heating operation in the room where the second indoor unit 4 is installed, and more specifically, the opening degree is set so that the refrigerant flowing into the second expansion valve 52 becomes a single-phase liquid refrigerant that has been completely condensed in the water-refrigerant heat exchanger 51.

[0068] The water heated while flowing through the water-side flow path 512 flows into the first water piping 11 from the water outlet 51d of the water-refrigerant heat exchanger 51. The water that has flowed into the first water piping 11 flows into the indoor heat exchanger 41 via the open on-off valve 43, and heats the indoor air passing through the indoor heat exchanger 41 by the rotation of the indoor fan 42. This heats the room in which the second indoor unit 4 is installed.

[0069] The water flowing out of the indoor heat exchanger 41 flows into the second water piping 12 and is sucked into the circulation pump 44. The water sucked into the circulation pump 44 is sent to the water inlet 51c of the water-refrigerant heat exchanger 51, passes through the water-side flow path 512, is heated again by the refrigerant flowing in the refrigerant-side flow path 511, and then flows out from the water outlet 51d toward the second indoor unit 4.

[0070] Meanwhile, the refrigerant that has flowed into the outdoor unit liquid pipe 63 passes through the outdoor expansion valve 24 and flows into the outdoor heat exchanger 23. The refrigerant that has flowed into the outdoor heat exchanger 23 evaporates by exchanging heat with outside air that has been taken into the outdoor unit 2 by the rotation of the outdoor fan 29. The refrigerant that has flowed out from the outdoor heat exchanger 23 flows through the refrigerant piping 62, and is sucked into the compressor 21 via the four-way valve 22, refrigerant piping 66, accumulator 25, and suction pipe 65, where it is compressed again. The opening of the outdoor expansion valve 24 is controlled to be fully open, or to an opening at which the temperature of the refrigerant discharged from the compressor 21 becomes a target discharge temperature.

[0071] [Control device details] The control device 90 controls the rotation speed of the compressor 21, the flow rate of the circulation pump 44, and the opening degree of the first expansion valve 33 and the second expansion valve 52, respectively, according to the capacity required by the first indoor unit 3 and the second indoor unit 4. For example, during cooling or heating operation, the control device 90 determines whether the indoor temperature has reached a set temperature, and stops the operation of the indoor unit installed in the room where the set temperature has been reached (hereinafter also referred to as thermo-off). At this time, the control device 90 fully closes or slightly opens the expansion valve corresponding to the indoor unit whose operation is to be stopped, thereby stopping the flow of refrigerant through the indoor heat exchanger of that indoor unit.

[0072] For example, when stopping the first indoor unit 3a, the control device 90 fully closes or slightly opens (hereinafter also referred to as slightly open) the first expansion valve 33 corresponding to the first indoor unit 3a. When stopping the second indoor unit 4a, the control device 90 fully closes or slightly opens the second expansion valve 52 of the relay unit 50a to which the second indoor unit 4a is connected, and further fully closes the on-off valve 43 corresponding to the second indoor unit 4a and stops the circulation pump 43 of the relay unit 50a. Similarly, when stopping the first indoor unit 3b, the control device 90 fully closes or slightly opens the first expansion valve 33 corresponding to the first indoor unit 3b. Furthermore, when stopping the second indoor unit 4b, the control device 90 fully closes or slightly opens the second expansion valve 52 of the relay unit 50b to which the second indoor unit 4b is connected, and further fully closes the on-off valve 43 corresponding to the second indoor unit 4b and stops the circulation pump 43 of the relay unit 50b. On the other hand, when all the indoor units (the first indoor unit 3, the second indoor unit 4) are stopped by turning off the thermostat or the like, the control device 90 stops the operation of the compressor 21 and the circulation pump 44. At this time, the opening degree of the expansion valve (particularly the second expansion valve 55) corresponding to the indoor unit that was last stopped may be fully closed, or may be maintained at the same opening degree.

[0073] Here, a compressor usually has a lower limit of the suction side pressure and an upper limit of the discharge side pressure according to the rotation speed as a specification, so reliability may decrease if the compressor is operated under conditions outside this range. Therefore, when the compressor stops operating due to the stop of operation of all indoor units, it is possible to stably restart the compressor by performing pressure equalization control, which is a control that reduces the pressure difference between high pressure and low pressure in the refrigerant circuit. As an example of pressure equalization control, a method is known in which the opening degree of the expansion valve of an indoor unit that has stopped operating due to thermo-off or the like is increased.

[0074] However, if the opening degree of the expansion valve is increased to perform pressure equalization control, refrigerant will flow into the indoor unit that has been stopped due to the thermostat being turned off, for example, and the noise of this refrigerant flowing may cause discomfort to users in the room where the indoor unit is installed.

[0075] In order to solve such problems, the control device 90 executes pressure equalization control in the following procedure, with the aim of suppressing discomfort to the user caused by refrigerant flow noise in the indoor unit when operation is stopped during pressure equalization control. Fig. 3 is a flowchart showing an example of the processing procedure executed by the control device 90.

[0076] (Overall control) During execution of the cooling operation mode or the heating operation mode, the control device 90 controls the rotation speed of the compressor 21 in accordance with the air conditioning loads of the first indoor unit 3 and the second indoor unit 4 (ST101). By controlling the rotation speed of the compressor 21 in this manner in accordance with the air conditioning loads of the first indoor unit 3 and the second indoor unit 4, indoor comfort can be maintained.

[0077] The air conditioning load of the first indoor unit 3 and the second indoor unit 4 is calculated, for example, based on the temperature (room temperature) of the room in which the first indoor unit 3 and the second indoor unit 4 are installed and the air conditioning temperature (set temperature) set in the indoor units. When multiple indoor units are in operation, the air conditioning load is the total value of the air conditioning load of each indoor unit.

[0078] The control device 90 monitors whether or not an instruction to change (increase or decrease) the number of operating indoor units (first indoor unit 3 and second indoor unit 4) has been received at a predetermined cycle (ST102). For example, when a user stops an indoor unit that is in operation, or when the indoor unit is temporarily stopped because the indoor temperature has reached a set temperature, the control device 90 determines that an instruction to decrease the number of operating indoor units has been received. When an instruction to decrease the number of operating indoor units is received, the control device 90 controls the expansion valves (first expansion valve 33, second expansion valve 52) corresponding to the indoor units that have been instructed to stop to be fully closed or slightly open.

[0079] At this time, the control device 90 judges whether or not the operation of all the indoor units (the first indoor unit 3 and the second indoor unit 4) has stopped (ST103). When the control device 90 judges that the operation of all the indoor units has not stopped (No in ST103), it controls the rotation speed of the compressor 21 in accordance with the air conditioning load of the indoor units in operation (ST101), and controls the opening degree of the expansion valve (the first expansion valve 33, the second expansion valve 52) corresponding to the changed indoor unit. On the other hand, when the control device 90 judges that the operation of all the indoor units has stopped (Yes in ST103), it stops the compressor 21 (ST104).

[0080] After stopping the compressor 21, the control device 90 executes the pressure equalization control shown in Fig. 4 (ST105). The pressure equalization control will be described in detail later.

[0081] Next, the control device 90 determines whether or not an operation start command has been received from the indoor units 3, 4 (ST106), and when an operation start command has been received, restarts the compressor 21 (ST107). The rotation speed of the compressor 21 is controlled according to the air conditioning load (the number of operating units) of the indoor units 3, 4, etc. (ST101). After that, the above-mentioned processing is repeatedly executed.

[0082] [Pressure equalization control] Next, the pressure equalization control (ST105) will be described in detail with reference to FIG. 4 and FIG.

[0083] (First control example) FIG. 4 is a flowchart showing a procedure of the pressure equalization control according to the first control example.

[0084] After stopping the compressor 21, the control device 90 determines whether or not the opening degree of the second expansion valve 52 provided in the relay unit 50 is equal to or greater than a first predetermined opening degree that is set in advance (ST201).

[0085] Here, the opening degree of the second expansion valve 52 refers to the opening degree of the second expansion valve 52 immediately before the compressor 21 is stopped. Therefore, the opening degree of the second expansion valve 52 when the second indoor unit 4 is not operating immediately before the compressor 21 is stopped is fully closed or slightly open, and the opening degree of the second expansion valve 52 when the second indoor unit 4 is operating immediately before the compressor 21 is stopped is the opening degree when the second indoor unit 4 is operating.

[0086] When multiple relay units 50 are connected as in this embodiment, it is determined whether the opening degree of the second expansion valve 52 in each relay unit 50a, 50b is equal to or greater than a first predetermined opening degree. For example, when the second indoor unit 4a is in operation and the second indoor unit 4b is not in operation, the opening degree of the second expansion valve 52 of the relay unit 50a connected to the second indoor unit 4a is the opening degree when the second indoor unit 4a is in operation, and the opening degree of the second expansion valve 52 of the relay unit 50b connected to the second indoor unit 4b is fully closed or slightly open.

[0087] On the other hand, the first predetermined opening degree is an opening degree required to equalize the pressure between the high pressure side and the low pressure side in the primary refrigerant circuit 20 within a predetermined time, and is determined in advance by experiments or the like according to the pipe length and pipe diameter of the refrigerant piping that forms the primary refrigerant circuit 20. Pressure equalization does not necessarily require the high pressure side and the low pressure side to be at the same pressure, but only requires that the differential pressure between the high pressure side and the low pressure side be equal to or less than a predetermined value. The predetermined time is an allowable value for the time required for pressure equalization, and is, for example, 180 seconds.

[0088] The first predetermined opening degree may be a larger opening degree than the opening degree of the first expansion valve 33 during operation of the first indoor unit 3. As a result, even if the indoor unit that was operating immediately before the compressor 21 was stopped was the first indoor unit 3 and the compressor 21 was stopped while maintaining the opening degree of the first expansion valve 33 when the first indoor unit 3 was stopped due to thermo-off or the like, the refrigerant tends to flow from the high pressure side to the low pressure side through the second expansion valve 52 controlled to an opening degree equal to or larger than the first predetermined opening degree. As a result, the inflow of the refrigerant into the indoor heat exchanger 31 of the first indoor unit 3 can be suppressed.

[0089] In this embodiment, the first predetermined opening degree is set according to the ratio of the in-pipe volume of the primary refrigerant of the water-refrigerant heat exchanger 51 to the total in-pipe volume of the primary refrigerant circuit 20. The total in-pipe volume refers to a volume (pipe length x pipe diameter) including the refrigerant piping connecting the discharge port and the suction port of the compressor 21, the outdoor heat exchanger 23, and the internal flow path of the water-refrigerant heat exchanger 51. The larger the ratio of the in-pipe volume of the primary refrigerant of the water-refrigerant heat exchanger 51 to the total in-pipe volume, the smaller the opening degree is set as the first predetermined opening degree. This makes it possible to relatively quickly equalize the pressure of the primary refrigerant circuit 20 while suppressing accumulation of refrigerant on the high-pressure side during pressure equalization control. In addition, since the first predetermined opening degree is set as described above, when the above ratios are different for the water-refrigerant heat exchangers 51 of the relay units 50a and 50b, the first predetermined opening degree may be set to a different opening degree for each of the second expansion valves 52 of the relay units 50a and 50b.

[0090] Next, when the control device 90 determines that the opening degree of the second expansion valve 52 is less than the first predetermined opening degree (No in ST201), it controls the opening degree of the second expansion valve 52 to the first predetermined opening degree (ST202). As a result, after the compressor 21 is stopped, the refrigerant on the high-pressure side in the primary refrigerant circuit 20 is more likely to flow out to the low-pressure side through the second expansion valve 52 and the water-refrigerant heat exchanger 51, so that the pressure in the primary refrigerant circuit 20 can be quickly equalized.

[0091] Also, because the refrigerant flows out from the high pressure side to the low pressure side via the water-refrigerant heat exchanger 51, the inflow of refrigerant into the indoor heat exchanger 31 of the first indoor unit 3 while operation is stopped is suppressed. This suppresses the generation of refrigerant flow noise in the first indoor unit 3, and also suppresses discomfort to a user in the room in which the first indoor unit is installed. Furthermore, because the relay unit 50 is installed outdoors, the flow noise of the refrigerant in the water-refrigerant heat exchanger 51 will not cause discomfort to a user in the room in which the second indoor unit 4 is installed.

[0092] On the other hand, when the control device 90 determines that the opening degree of the second expansion valve 52 is equal to or greater than the first predetermined opening degree (Yes in ST201), the control device 90 maintains the opening degree of the second expansion valve 52 at that opening degree (equal to or greater than the first predetermined opening degree) (ST203). This enables pressure equalization of the primary refrigerant circuit 20 to be performed in a shorter time.

[0093] (Second control example) 5 is a flowchart showing the procedure of pressure equalization control according to the second control example. This control example differs from the first control example in that the following processes (S301-304) are executed before executing pressure equalization control (ST201-203) for controlling the opening degree of the second expansion valve 52 to the first predetermined opening degree or more.

[0094] After stopping the compressor 21, the control device 90 determines whether the relationship between the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 and the temperature of the water flowing into the water-refrigerant heat exchanger 51 satisfies a predetermined relationship (ST301).

[0095] Here, the specified relationship means that in cooling operation, i.e., in an operating state in which the water-refrigerant heat exchanger 51 of the relay unit 50 functions as an evaporator, the refrigerant temperature detected by the first refrigerant temperature sensor 78 when the compressor 21 is stopped is lower than the water temperature detected by the water temperature sensor 80, and that in heating operation, i.e., in an operating state in which the water-refrigerant heat exchanger 51 of the relay unit 50 functions as a condenser, the refrigerant temperature detected by the second refrigerant temperature sensor 79 when the compressor 21 is stopped is higher than the water temperature detected by the water temperature sensor 80.

[0096] When the control device 90 determines that the refrigerant temperature and the water temperature satisfy the above-mentioned predetermined relationship (Yes in ST301), it starts the circulation pump 44 of the secondary refrigerant circuit 40 (ST302). This increases the heat exchange amount in the water-refrigerant heat exchanger 51, increasing the evaporation pressure of the refrigerant in the relay unit 50 during cooling operation and decreasing the condensation pressure of the refrigerant in the relay unit 50 during heating operation, thereby reducing the pressure difference between high and low pressures in the primary refrigerant circuit 20. This can promote pressure equalization in the primary refrigerant circuit 20.

[0097] The processes in ST301 and ST302 may be performed after the pressure equalization control (ST201 to ST203). In this case as well, the pressure equalization of the primary refrigerant circuit 20 can be promoted.

[0098] Next, the control device 90 determines whether the second expansion valve 52 is fully closed (ST303). When a plurality of relay units 50 are connected as in this embodiment, it determines whether the second expansion valves 52 of all relay units 50 are fully closed. When the second expansion valve 52 is fully closed (Yes in ST303), the control device 90 controls the opening of the first expansion valve 33 corresponding to the first indoor unit 3 to a second predetermined opening that is set in advance (ST304).

[0099] The second predetermined opening is set to an opening corresponding to a flow rate smaller than the flow rate of the primary refrigerant corresponding to the first predetermined opening. By determining the second predetermined opening based on the refrigerant flow rate in this manner, the second predetermined opening can be appropriately set even when an expansion valve having a valve diameter different from that of the second expansion valve 52 is used as the first expansion valve 33.

[0100] In this manner, by controlling the opening degree of the first expansion valve 33 to the second predetermined opening degree before executing the pressure equalization control (ST201-203), the refrigerant in the primary refrigerant circuit 20 can be caused to flow from the high pressure side to the low pressure side via the first expansion valve 33 during the pressure equalization control, thereby suppressing accumulation of refrigerant on the high pressure side.

[0101] On the other hand, when it is determined in ST303 that the opening degree of the second expansion valve 52 is not fully closed (No in ST303), the control device 90 executes the pressure equalization control (ST201 to 203) without controlling the opening degree of the first expansion valve 33 to the second predetermined opening degree.

[0102] As described above, by executing ST301-304 before executing the pressure equalization control (ST201-203), it is possible to execute the pressure equalization control in a shorter time, thereby shortening the time from stopping compressor 21 to restarting it.

[0103] The processes in ST303 and ST304 may be performed before the processes in ST301 and ST302. In this case as well, pressure equalization in the primary refrigerant circuit 20 can be promoted.

[0104] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made thereto.

[0105] For example, in the above embodiment, an example has been described in which one second indoor unit 4 is connected to each relay unit 50, but the present invention is not limited to this and can also be applied to a refrigeration cycle apparatus in which a plurality of second indoor units 4 are connected in parallel to one relay unit 50. In this case, when the operation of each second indoor unit 4 is stopped by turning off the thermostat or the like, the on-off valves connected corresponding to each second indoor unit 4 are closed, and when the operation of all the second indoor units 4 has stopped, the second expansion valve of the relay unit is fully closed. [Explanation of symbols]

[0106] 2…Outdoor unit 3(3a,3b)…1st indoor unit 4(4a,4b)…Second indoor unit 20...Refrigerant circuit 21...Compressor 22...Four-way valve 23…Outdoor heat exchanger 40…Water circuit 31…Indoor heat exchanger (refrigerant heat exchanger) 32,42…Indoor fan 33…First expansion valve 41…Indoor heat exchanger (water heat exchanger) 43…Indoor expansion valve 44…Circulation pump 50 (50a, 50b) ... Relay unit 51…Water refrigerant heat exchanger 52…Second expansion valve 78, 79...Refrigerant temperature sensor (primary refrigerant temperature detection section) 80...Water temperature sensor (secondary refrigerant temperature detection section) 90...Control device 100…Air conditioner

Claims

1. a primary refrigerant circuit including an outdoor unit having a compressor and an outdoor heat exchanger, at least one first indoor unit having a refrigerant heat exchanger and a first expansion valve, and at least one relay unit having a water-refrigerant heat exchanger for exchanging heat between a refrigerant and water and a second expansion valve, the relay unit being connected to the outdoor unit in parallel with the first indoor unit, and in which a primary refrigerant circulates; a control device that controls the compressor, the first expansion valve, and the second expansion valve, The control device controls the opening degree of the second expansion valve to a first predetermined opening degree or more when the compressor is stopped. Refrigeration cycle equipment.

2. The refrigeration cycle apparatus according to claim 1, When the opening degree of the second expansion valve when the compressor is stopped is less than the first predetermined opening degree, the control device controls the opening degree of the second expansion valve to the first predetermined opening degree. Refrigeration cycle equipment.

3. The refrigeration cycle apparatus according to claim 1, When the opening degree of the second expansion valve when the compressor is stopped is equal to or greater than the first predetermined opening degree, the control device maintains the opening degree of the second expansion valve at equal to or greater than the first predetermined opening degree. Refrigeration cycle equipment.

4. The refrigeration cycle apparatus according to claim 1, The water-refrigerant heat exchanger is connected to a secondary refrigerant circuit including a second indoor unit having a water heat exchanger and a circulation pump, through which a secondary refrigerant circulates; The relay unit includes: a primary refrigerant temperature detection unit that detects a temperature of the primary refrigerant flowing into the water-refrigerant heat exchanger; a secondary refrigerant temperature detection unit that detects the temperature of the secondary refrigerant flowing into the water-refrigerant heat exchanger, The control device operates the circulating pump when the compressor is stopped in an operating state in which the relay unit functions as a condenser and a detection value of the primary refrigerant temperature detection unit is higher than a detection value of the secondary refrigerant temperature detection unit. Refrigeration cycle equipment.

5. The refrigeration cycle apparatus according to claim 1, The water-refrigerant heat exchanger is connected to a secondary refrigerant circuit including a second indoor unit having a water heat exchanger and a circulation pump, through which a secondary refrigerant circulates; The relay unit includes: a primary refrigerant temperature detection unit that detects a temperature of the primary refrigerant flowing into the water-refrigerant heat exchanger; a secondary refrigerant temperature detection unit that detects the temperature of the secondary refrigerant flowing into the water-refrigerant heat exchanger, The control device operates the circulating pump when the compressor is stopped in an operating state in which the relay unit functions as an evaporator and a detection value of the primary refrigerant temperature detection unit is lower than a detection value of the secondary refrigerant temperature detection unit. Refrigeration cycle equipment.

6. The refrigeration cycle apparatus according to claim 1, The first predetermined opening degree is set according to a ratio of an internal volume of the primary refrigerant in the water-refrigerant heat exchanger to a total internal volume of the primary refrigerant circuit, and is set to a smaller opening degree as the ratio increases. Refrigeration cycle equipment.

7. The refrigeration cycle apparatus according to any one of claims 1 to 6, When the compressor is stopped with the second expansion valve fully closed, the control device controls the opening degree of the first expansion valve to a second predetermined opening degree, which is an opening degree corresponding to a flow rate of the primary refrigerant smaller than a flow rate of the primary refrigerant corresponding to the first predetermined opening degree. Refrigeration cycle equipment.

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