Control device for outdoor unit, outdoor unit, heat pump device, and control method for outdoor unit

Abstract

Provided are a control device for an outdoor unit and a control method for the outdoor unit that make it possible to reliably reduce the risk of fire caused by leakage of a refrigerant into the outdoor unit. A control device (50) for an outdoor unit comprises: a control unit (51) that controls rotation of a fan (61) provided to an outdoor unit; and a storage unit (52) that stores information related to detection of leakage of refrigerant from a refrigerant detection sensor that detects leakage of refrigerant into the outdoor unit. The control unit (51) starts the rotation of the fan (61) when the storage unit (52) is storing information related to the detection of leakage of refrigerant from the refrigerant detection sensor when the power of the outdoor unit is turned on.

Description

Outdoor unit control device, outdoor unit, heat pump device, and outdoor unit control method

[0001] The present disclosure relates to an outdoor unit control device, an outdoor unit, a heat pump device, and an outdoor unit control method.

[0002] There has been reported a technique of providing a refrigerant detection sensor for detecting a leaked refrigerant and operating a blower fan at a first rotational speed when the refrigerant detection sensor detects a gas concentration equal to or higher than a predetermined level (Patent Document 1). Further, Patent Document 2 reports a technique of operating a stirring fan provided outside the housing of a repeater at the start of operation.

[0003] Japanese Patent No. 7484082, Japanese Patent No. 7243132

[0004] However, in the technique of Patent Document 1, since the fan is not rotated until the leakage of the refrigerant is detected, there is a problem that the ignition concentration is maintained during that time. In particular, since the refrigerant detection sensor does not operate while the power supply of the outdoor unit is OFF, the fan cannot be operated until detection after the power supply is turned ON. Further, when an abnormality display appears due to refrigerant detection, the user may turn off the power without fully understanding the content of the abnormality display and restart it, and in such a case, the risk further expands.

[0005] Also, when using a natural refrigerant, it takes time to initialize the refrigerant detection sensor for identification with other natural refrigerants. Therefore, it may take time until refrigerant detection (for example, 80 seconds). Further, in order to remove false detection of the refrigerant detection sensor, there is a problem that it takes time to judge leakage after continuous detection (for example, 20 seconds).

[0006] Further, Patent Document 2 is a technique of rotating a stirring fan provided outside the housing of a repeater, and is not a technique focusing on the fan of an outdoor unit.

[0007] As described above, there has been a demand for a technique of reducing the risk of ignition due to leakage of refrigerant in an outdoor unit.

[0008] This disclosure is made in view of these circumstances and aims to provide an outdoor unit control device, an outdoor unit, a heat pump device, and an outdoor unit control method that can reliably reduce the risk of ignition due to refrigerant leakage into the outdoor unit.

[0009] To solve the above problems, the outdoor unit control device of the present disclosure comprises a control unit that controls the rotation of a fan provided on the outdoor unit, and a storage unit that stores information on the detection of refrigerant leakage from a refrigerant detection sensor that detects refrigerant leakage into the outdoor unit, wherein the control unit starts the rotation of the fan when the power of the outdoor unit is turned ON and the storage unit has stored information on the detection of refrigerant leakage from the refrigerant detection sensor.

[0010] Furthermore, the method for controlling an outdoor unit according to this disclosure is a method for controlling an outdoor unit comprising a fan and a refrigerant detection sensor for detecting refrigerant leakage into the unit, comprising a control step for controlling the rotation of the fan and a storage step for storing information that the refrigerant leakage detected from the refrigerant detection sensor has been detected, wherein in the control step, when the power of the outdoor unit is turned ON, if the storage step has stored information that the refrigerant leakage detected from the refrigerant detection sensor has been detected, the rotation of the fan is started.

[0011] With the outdoor unit control device described in this disclosure, refrigerant leakage can be detected before the outdoor unit's power is turned off, and if there is a risk of ignition due to refrigerant leakage, the fan can be quickly started to rotate. This reliably reduces the risk of ignition due to refrigerant leakage inside the outdoor unit.

[0012] This is a perspective view showing an outdoor unit according to the first embodiment of this disclosure. This is a vertical cross-sectional view of the outdoor unit in Figure 1. This is a diagram showing the configuration of the control system by the control device of the outdoor unit according to the first embodiment of this disclosure. This is a schematic diagram of the refrigeration cycle of a heat pump device. This is a flowchart showing the control method by the control device of the outdoor unit according to the first embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 1 of the first embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 2 of the first embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 3 of the first embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 4 of the first embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to the second embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 1 of the second embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 2 of the second embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 3 of the second embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to modification 4 of the second embodiment of this disclosure. This is a flowchart showing the control method by the control device of the outdoor unit according to the third embodiment of this disclosure. This flowchart shows a control method by an outdoor unit control device according to Modification 1 of the third embodiment of this disclosure. This flowchart shows a control method by an outdoor unit control device according to Modification 2 of the third embodiment of this disclosure. This flowchart shows a control method by an outdoor unit control device according to Modification 3 of the third embodiment of this disclosure. This flowchart shows a control method by an outdoor unit control device according to Modification 4 of the third embodiment of this disclosure.

[0013] An embodiment of the control device for an outdoor unit, an outdoor unit, a heat pump system, and a control method for an outdoor unit according to this disclosure will be described below with reference to the drawings.

[0014] [First Embodiment] A first embodiment of the present disclosure will be described below with reference to the drawings. Figure 1 shows an outdoor unit 1 used in a heat pump system. The outdoor unit 1 in Figure 1 is shown with the panel of the machine room 7 removed.

[0015] The outdoor unit 1 is connected to the indoor unit (heat utilization unit) via a water circuit using water piping (heat transfer piping) not shown. Water circulates between the outdoor unit 1 and the indoor unit through the water piping. As a result, the heat or cold generated by the outdoor unit 1 is sent to the indoor unit via the water piping, providing heat or cold to the room.

[0016] As shown in Figure 1, the outdoor unit 1 has a roughly rectangular prism-shaped housing 3. The bottom of the housing 3 is a sheet metal base 4. The base 4 has base legs 4a provided on each side along the longitudinal direction, and a roughly flat plate portion 4b provided between the upper ends of the base legs 4a on both sides. The flat plate portion 4b extends roughly horizontally, and various devices are installed on top of it. The flat plate portion 4b has irregularities formed by press working.

[0017] As shown in Figure 1, the housing 3 contains a fan room 5 and a machine room 7 located above the base 4, separated to the left and right by a partition wall 9.

[0018] The fan chamber 5 is located on the left side in Figure 1. Inside the fan chamber 5 are an outdoor fan 61 (not shown in Figure 1) and an outdoor heat exchanger 30 (see Figure 2). The outdoor heat exchanger 30 is bent into an L-shape so as to form the side and back of the fan chamber 5. Outside air drawn in by the outdoor fan 61 exchanges heat with the refrigerant circulating in the outdoor heat exchanger 30. After exchanging heat with the refrigerant, the outside air is discharged to the outside through the fan opening 11.

[0019] The machine room 7 is located on the right side in Figure 1. The machine room 7 is provided with a plate-shaped sub-base 13 on top of the base 4 (specifically, the flat plate portion 4b). The sub-base 13 is rectangular in shape when viewed from above and is sized to cover almost the entire area below the machine room 7. However, a predetermined gap is formed around the four sides of the sub-base 13 between it and the side walls and partition walls 9 of the opposing housing 3.

[0020] As shown in Figure 2, multiple sub-base support members 15 equipped with vibration-damping rubber are provided between the base 4 and the sub-base 13. Each sub-base support member 15 supports the sub-base 13 relative to the base 4.

[0021] As shown in Figure 1, the machine room 7 is equipped with a compressor 17, a water heat exchanger 19, a gas separator 21, a control box 23, and the like, above the sub-base 13.

[0022] The compressor 17 is, for example, a rotary compressor, and compresses a flammable refrigerant such as R290. As shown in Figure 2, the lower part of the compressor 17 is provided with compressor legs 17a equipped with vibration-damping rubber. The compressor legs 17a are mounted on the sub-base 13. The compressor legs 17a equipped with vibration-damping rubber reduce the vibrations of the compressor 17 transmitted to the sub-base 13. The sub-base 13 does not have unnecessary through holes, except for holes for mounting equipment such as the sub-base support member 15 and the compressor legs 17a. Therefore, after the equipment is mounted, there are basically no through holes in the sub-base 13.

[0023] The refrigerant compressed by the compressor 17 is sent to the water heat exchanger 19 or the outdoor heat exchanger 30 via a four-way valve (not shown). The compressor 17, the four-way valve (not shown), the water heat exchanger 19, the outdoor heat exchanger 30, the expansion valve (not shown), and the refrigerant piping connecting them form a refrigerant circuit through which the refrigerant circulates.

[0024] The water heat exchanger 19 exchanges heat between the refrigerant and water (heat transfer medium). After the water has exchanged heat with the refrigerant, the gas (air, refrigerant, etc.) is separated by the gas separator 21, and then the water is guided to the indoor unit through the water supply pipe 25. After the water has exchanged heat with the indoor air in the indoor unit, it is returned to the water heat exchanger 19 through the water return pipe 26. In this way, the water circulates between the water heat exchanger 19 and the indoor unit via the water circuit.

[0025] The control box 23 has a sealed structure that houses electrical equipment such as capacitors and coils inside. Furthermore, the control box 23 is equipped with a terminal block that has electrical terminals (electrical equipment) that receive power from the outside. Thus, the control box 23 is considered a potential source of ignition in which electrical energy is present.

[0026] Figure 2 also shows the same compressor 17, water heat exchanger 19, and gas separator 21 as in Figure 1. An accumulator 28 is shown to the side of the compressor 17. An outdoor heat exchanger 30 is also shown on the right side of Figure 2. The outdoor heat exchanger 30 is installed in the fan room 5 (see Figure 1) as described above.

[0027] Although not shown in the diagram, the base 4 is provided with a drain hole in a position corresponding to the fan chamber 5. The drain hole is, for example, circular in shape, with a diameter of, for example, 20 mm. The drain hole is located on the lower surface, which is the lowest position on the flat plate portion 4b of the base 4. The lower surface extends continuously across the machine chamber 7. The lower surface is inclined so that the drain hole faces downwards. This allows condensed water to adhere to equipment such as the outdoor heat exchanger 30 inside the housing 3 and flow downwards, so that the drain water can be discharged to the outside through the drain hole via the lower surface.

[0028] As shown in Figure 2, the base 4 is provided with a refrigerant discharge hole 34 at a position corresponding to the machine room 7. Through the refrigerant discharge hole 34, the refrigerant released into the machine room 7 is discharged to the outside (atmosphere).

[0029] The refrigerant discharge hole 34 is, for example, circular in shape, with a diameter of 30 mm or more, preferably about 60 mm. In other words, the area of ​​the refrigerant discharge hole 34 is larger than the area of ​​the drain hole.

[0030] As shown in Figure 2, a resin mesh 40 is provided at the refrigerant discharge hole 34 to prevent small animals such as insects from entering the inside of the housing 3 from the outside.

[0031] A refrigerant detection sensor 42 is installed below the machine room 7. The refrigerant detection sensor 42 detects the refrigerant (refrigerant concentration) leaked into the machine room 7. The detection output of the refrigerant detection sensor 42 is transmitted to a control device 50 (not shown in Figure 2). The refrigerant detection sensor 42 is installed below the gas separator 21. Details of the control device 50 will be described later.

[0032] A water connection pipe 46 is connected to the side of the gas separator 21 to guide water from the water heat exchanger 19.

[0033] Figure 3 is a diagram showing the configuration of the control system by the control device for the outdoor unit according to this embodiment. As shown in Figure 3, the control device 50 comprises a control unit 51 and a storage unit 52.

[0034] The control device 50 is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example. The CPU reads this program into the RAM and performs information processing and calculations to realize the various functions. The program may be pre-installed on the ROM or other storage medium, provided in a state where it is stored on a computer-readable storage medium, or distributed via wired or wireless communication. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memory, etc.

[0035] The control unit 51 controls the rotation of the fan (outdoor fan) 61 provided on the outdoor unit 1 via the fan drive unit 62. The storage unit 52 stores information (refrigerant leak detection information) that has been detected from the refrigerant detection sensor 42.

[0036] When the power to the outdoor unit 1 is turned ON, if the storage unit 52 has stored refrigerant leak detection information from the refrigerant detection sensor 42, the control unit 51 controls the fan drive unit 62 to start the rotation of the fan 61. The storage unit 52 stores only refrigerant leak detection information (in particular, information indicating that refrigerant is leaking) that was input during the power-on cycle immediately prior to the current power-on cycle (the period from when the power is turned ON until when it is turned OFF). In other words, refrigerant leak detection information that was input during power-on cycles two or more prior to the current power-on cycle is not stored. It is also possible to change the rotation speed of the fan 61 according to the detected refrigerant concentration.

[0037] Figure 4 shows a schematic configuration of the refrigeration cycle of a heat pump system using the outdoor unit 1 with the above configuration. Note that the same components shown in Figures 1 and 2 are indicated by the same reference numerals.

[0038] The refrigerant circuit C, which constitutes the refrigeration cycle, includes a compressor 17, a water heat exchanger 19, expansion valves 45A and 45B, a receiver 80 located between the expansion valves 45A and 45B, and an outdoor heat exchanger 30. A check valve 18 is connected to a discharge pipe 47 connected to the discharge port of the compressor 17, and a four-way valve (switching valve) 49 is provided downstream of it. An accumulator 28 and an suction pressure sensor 29 are provided upstream of the suction port of the compressor 17. The output of the suction pressure sensor 29 is transmitted to the control unit. Excess refrigerant in the refrigerant circuit C is stored in the receiver 80.

[0039] A liquid refrigerant piping 71 between the expansion valve 45A and the water heat exchanger 19 has a liquid pipe temperature sensor 73 installed in close proximity to the water heat exchanger 19. The output of the liquid pipe temperature sensor 73 is transmitted to the control unit.

[0040] A water circuit W is connected to the water heat exchanger 19. The water circuit W includes an indoor unit (heat utilization unit) (not shown), a gas separator 21, a water pump (heat transfer medium pump) 75, a three-way valve 81, and a water tank 82. The gas separator 21, the three-way valve 81, and the water tank 82 are located on the water outlet side of the water heat exchanger 19, while the water pump 75 is located on the water inlet side of the water heat exchanger 19. A water inlet temperature sensor 77 is provided on the water inlet side of the water heat exchanger 19, and a water outlet temperature sensor 79 is provided on the water outlet side of the water heat exchanger 19. The output of each temperature sensor 77 is transmitted to the control unit. The three-way valve 81 selectively switches the flow path of water from the water heat exchanger 19 between a flow path to the indoor unit and a flow path to the water tank 82. Water is stored in the water tank 82. When a refrigerant leak is detected, the three-way valve 81 is switched to the water tank 82, so that the refrigerant mixed into the water circuit W flows only to the water tank 82. This reduces the risk of refrigerant reaching various indoor units. A heater may be installed at any point between the water heat exchanger 19 and the three-way valve 81 (especially where the pipes constituting the water circuit W are exposed to the outside).

[0041] The gas separator 21 has an ejection nozzle 21a that protrudes upward from the top of the gas separator 21 to eject the separated gas (such as refrigerant or air). The ejection nozzle 21a is equipped with a check valve, and when the separated gas exceeds a predetermined pressure, the check valve opens and the gas is ejected to the outside.

[0042] A water relief outlet 21b is provided on the side of the gas separator 21, which has a pressure relief valve that opens when the pressure of the incoming water exceeds a predetermined value. A water discharge pipe that leads water to the outside of the outdoor unit 1 is connected to the water relief outlet 21b, although it is not shown in the figure.

[0043] The heat pump device shown in Fig. 4 operates as follows. <Cooling mode> In the cooling mode, the four-way valve 49 is switched according to the command of the control unit and operates as shown by the solid-line arrow. The high-pressure refrigerant discharged from the compressor 17 passes through the four-way valve and is sent to the outdoor heat exchanger 30. In the outdoor heat exchanger 30, heat is released to the outside air and the refrigerant is condensed. The condensed and liquefied refrigerant is sent to the expansion valves 45A and 45B, and the refrigerant is decompressed to a predetermined pressure by the expansion valves 45A and 45B. The opening degrees of the expansion valves 45A and 45B are controlled by the control unit.

[0044] The refrigerant decompressed by the expansion valves 45A and 45B is sent to the water heat exchanger 19, absorbs heat from the water flowing through the water heat exchanger 19, and is evaporated. The refrigerant evaporated in the water heat exchanger 19 is guided to the suction side of the compressor 17 through the four-way valve 49 and the accumulator 28.

[0045] The cold water generated by being cooled by the latent heat of evaporation of the refrigerant in the water heat exchanger 19 flows to the gas separator 21 by the water pump 75. In the gas separator 21, gases such as the refrigerant and air contained in the cold water are separated, and the separated cold water is sent to the indoor unit. The cold water that has completed cooling in the indoor unit is returned to the water pump 75 and is again guided to the water heat exchanger 19.

[0046] <Heating mode> In the heating mode, the four-way valve 49 is switched according to the command of the control unit and operates as shown by the dashed-line arrow. The high-pressure refrigerant discharged from the compressor 17 passes through the four-way valve and is sent to the water heat exchanger 19. In the water heat exchanger 19, heat is released to the water led from the water circuit W, and the water is heated to become hot water.

[0047] The refrigerant condensed and liquefied in the water heat exchanger 19 is sent to the expansion valves 45A and 45B, and the refrigerant is decompressed to a predetermined pressure by the expansion valves 45A and 45B. The opening degrees of the expansion valves 45A and 45B are controlled by the control unit.

[0048] The refrigerant decompressed by the expansion valves 45A and 45B is sent to the outdoor heat exchanger 30, absorbs heat from the outside air, and evaporates. The refrigerant evaporated in the outdoor heat exchanger 30 is guided to the suction side of the compressor 17 through the four-way valve 49 and the accumulator 28.

[0049] The hot water generated in the water heat exchanger 19 by the latent heat of condensation of the refrigerant flows to the gas separator 21 via the water pump 75. In the gas separator 21, gases such as refrigerant and air contained in the hot water are separated, and the separated hot water is sent to the indoor unit. After heating in the indoor unit, the hot water is returned to the water pump 75 and guided back to the water heat exchanger 19.

[0050] Next, an example of a control method using the control device 50 described above will be explained with reference to Figure 5. Figure 5 is a flowchart showing the control method using the control device 50 of the outdoor unit in this embodiment.

[0051] In step S101, the refrigerant detection sensor 42 detects refrigerant leaking into the machine room 7 and detects refrigerant leakage into the outdoor unit 1. The information that the refrigerant detection sensor 42 has detected a refrigerant leak (refrigerant leak detection information) is output to the control device 50.

[0052] In step S102, the control device 50, having received refrigerant leak detection information from the refrigerant detection sensor 42, detects an abnormality and displays an abnormality indicator on a monitor or the like. Accordingly, the control unit 51 controls the fan 61 to start rotating via the fan drive unit 62. The control device 50 also writes (stores) the refrigerant leak detection information to the memory unit (CPU) 52 (storage step).

[0053] In step S103, the power (circuit breaker) to the outdoor unit 1 is turned OFF. One reason the power is turned OFF after step S102 is that when the user detects an error on the outdoor unit 1 due to refrigerant detection, they turn off the power without fully understanding the content of the error message. At this time, the refrigerant detection sensor 42 also stops.

[0054] In step S104, the power to the outdoor unit 1 is turned ON.

[0055] In step S105, the control device 50 checks whether or not there is refrigerant leak detection information in the storage unit 52. If there is no refrigerant leak detection information in the storage unit 52, the process proceeds to step S106 and the outdoor unit 1 is started as usual. On the other hand, if there is refrigerant leak detection information in the storage unit 52, the process proceeds to step S107 and the control unit 51 immediately starts the rotation of the fan 61 via the fan drive unit 62 (control process). An abnormality is also displayed on a monitor or the like.

[0056] In step S108, the refrigerant detection sensor 42 is activated. Since it takes time to activate the refrigerant detection sensor 42, in this embodiment, the fan 61 is started to rotate before the refrigerant detection sensor 42 is activated.

[0057] In step S109, the refrigerant detection sensor 42 detects a refrigerant leak into the outdoor unit 1, and the control device 50 determines whether or not there is a refrigerant leak. If it is determined in step S109 that there is a refrigerant leak, the process proceeds to step S110 and the fan 61 continues to rotate. After a predetermined time has elapsed since the determination of whether or not there is a refrigerant leak, the refrigerant detection sensor 42 and the control device 50 make the determination again. In this way, steps S109 to S110 are repeated until it is determined in step S109 that there is no refrigerant leak.

[0058] If it is determined in step S109 that there is no refrigerant leak, the process proceeds to step S111, where the control unit 51 stops the rotation of the fan 61. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started up as usual.

[0059] As described above, this embodiment provides the following effects. The control device 50 of the outdoor unit 1 in this embodiment includes a storage unit 52 that stores information about refrigerant leakage detected from a refrigerant detection sensor 42 that detects refrigerant leakage into the outdoor unit 1. Therefore, if the refrigerant detection sensor 42 detects refrigerant leakage, the storage unit 52 can store the information about the detected refrigerant leakage even if the power to the outdoor unit 1 is turned OFF. In addition, in the control device 50 of this embodiment, the control unit 51 starts the rotation of the fan 61 when the power to the outdoor unit 1 is turned ON and the storage unit 52 has stored information about refrigerant leakage detected from the refrigerant detection sensor 42. Therefore, if refrigerant leakage is detected before the power to the outdoor unit 1 is turned OFF and there is a risk of ignition due to refrigerant leakage, the rotation of the fan 61 can be started quickly. This reliably reduces the risk of ignition due to refrigerant leakage into the outdoor unit 1.

[0060] Furthermore, since the outdoor unit 1 of this embodiment is equipped with the control device 50 described above, the risk of ignition due to refrigerant leakage into the outdoor unit 1 can be reliably reduced.

[0061] Furthermore, since the heat pump system of this embodiment is equipped with the control device 50 described above, the risk of ignition due to refrigerant leakage into the outdoor unit 1 can be reliably reduced.

[0062] Furthermore, the control method for the outdoor unit 1 in this embodiment includes a storage step that stores information about refrigerant leakage detected by a refrigerant detection sensor 42, which detects refrigerant leakage into the outdoor unit 1. Therefore, if the refrigerant detection sensor 42 detects refrigerant leakage, the information about the detected refrigerant leakage can be stored in the storage step even if the power to the outdoor unit 1 is turned OFF. In addition, in the control method of this embodiment, if the information about refrigerant leakage detected by the refrigerant detection sensor 42 is stored in the storage step when the power to the outdoor unit 1 is turned ON, the fan 61 starts rotating. Therefore, if refrigerant leakage is detected before the power to the outdoor unit 1 is turned OFF and there is a risk of ignition due to refrigerant leakage, the fan 61 can be quickly started to rotate. This reliably reduces the risk of ignition due to refrigerant leakage into the outdoor unit 1.

[0063] [Modification 1] Next, Modification 1 of this embodiment will be described with reference to Figure 6. In this modification, instead of determining whether or not there is a refrigerant leak based on the detection result of the refrigerant detection sensor 42 in step S109, step S121 confirms whether a predetermined time has elapsed since the fan 61 started rotating, which is different from the first embodiment. Other points are the same as in the first embodiment, so the same reference numerals are used for similar steps and their detailed explanations are omitted.

[0064] After step S108, the process proceeds to step S121. In step S121, it is checked whether a predetermined time has elapsed since the fan 61 started rotating. The predetermined time is set to a time at which, even if the entire amount of refrigerant flowing through the refrigerant circuit C leaks slowly, it is considered that no area around the outdoor unit 1 will reach the ignition concentration. Slow leak refers to the lowest leakage rate at which, when refrigerant leaks, the local concentration of refrigerant mixed with the surrounding environment around the outdoor unit 1 can reach the ignition concentration. The predetermined time can be calculated based on the total amount of refrigerant and the minimum leakage rate mentioned above. If the predetermined time for ending refrigerant suction is determined based on the assumption that the refrigerant leaks at high speed, the fan 61 will stop rotating while the refrigerant leak is still continuing if the refrigerant leaks slowly. In this case, there is a risk that an area around the outdoor unit will reach a refrigerant concentration higher than the ignition concentration. On the other hand, by determining the predetermined time based on the assumption that the refrigerant leaks slowly, it is possible to reliably prevent the occurrence of an area around the outdoor unit 1 that reaches the ignition concentration not only when the refrigerant leaks at high speed but also when it leaks slowly.

[0065] If the predetermined time has not elapsed in step S121, the process proceeds to step S110, and the fan 61 continues to rotate until the predetermined time has elapsed.

[0066] If a predetermined time has elapsed in step S121, the process proceeds to step S111, and the control unit 51 stops the rotation of the fan 61. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leakage into the outdoor unit 1.

[0067] This modified version achieves the same effects as the first embodiment described above. In this modified version, the control unit 51 stops the rotation of the fan 61 after a predetermined time has elapsed since the fan 61 started rotating. By rotating the fan 61, even if refrigerant leakage occurs, the area around the outdoor unit 1 that reaches the ignition concentration can be reliably narrowed. Therefore, the installation restrictions around the outdoor unit 1 can be relaxed, which is advantageous in terms of installation restrictions. The predetermined time is set to a time when, even assuming that the entire amount of refrigerant flowing through the refrigerant circuit C is slowly leaking, an area that reaches the ignition concentration around the outdoor unit 1 is not expected to occur.

[0068] [Modification 2] Next, Modification 2 of this embodiment will be described with reference to Figure 7. This modification differs from Modification 1 of the first embodiment in that step S122 is performed instead of step S107, step S123 is performed instead of step S110, and step S124 is performed instead of step S111. Other points are the same as Modification 1 of the first embodiment, so the same reference numerals are used for the same steps and their detailed description is omitted.

[0069] After step S105, if there is refrigerant leak detection information in the storage unit 52, the system proceeds to step S122, and the control unit 51 immediately starts the rotation of the fan 61 via the fan drive unit 62. At this time, the control unit 51 performs control to prohibit the starting of the compressor 17. It also displays an error message on a monitor or the like.

[0070] Step S108 is the same as in the first embodiment, so its description is omitted. After step S108, the process proceeds to step S121. In step S121, it is checked whether a predetermined time has elapsed since the fan 61 started rotating. If the predetermined time has not elapsed in step S121, the process proceeds to step S123, and the fan 61 continues to rotate until the predetermined time has elapsed. The compressor 17 is also kept shut off.

[0071] If a predetermined time has elapsed in step S121, the process proceeds to step S124, where the control unit 51 stops the rotation of the fan 61. At this time, the prohibition on starting the compressor 17 is released. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any leakage of refrigerant into the outdoor unit 1.

[0072] This modified version provides the same effects as Modification 1 of the first embodiment described above. Furthermore, it prevents the compressor 17 from starting up while refrigerant is leaking inside the outdoor unit 1. This reliably reduces the risk of ignition caused by the starting of the compressor 17.

[0073] In this modified example, the compressor 17 was disabled in step S122. However, instead of disabling the compressor 17, another control mechanism may be used to reduce the risk of ignition. For example, the water pump 75 may be disabled. This prevents refrigerant from leaking into the room via water by keeping the water pump 75 in the OFF state, for example, if the water heat exchanger 19 is damaged and refrigerant is leaking. At this time, the remote control displays that the water pump 75 is OFF and the fan is operating. In other words, it notifies the user of the control status of the outdoor unit 1.

[0074] The control unit 51 can also control the flow direction of the three-way valve 81 in the water circuit W from the direction of the indoor unit to the direction of the water tank 82. This prevents leaked refrigerant from flowing into the indoor unit side via water.

[0075] A heater (not shown) may be provided between the water heat exchanger 19 and the three-way valve 81 in the water circuit W, and the control unit 51 may activate this heater. If refrigerant leaks from the refrigerant circuit C, the temperature of the refrigerant circuit C will drop, causing the water on the water circuit W side of the water heat exchanger 19 to freeze, which poses a risk of damage to the water heat exchanger 19. Therefore, by activating the heater when refrigerant leaks and raising the temperature of the water flowing through the water circuit W, freezing of the water in the water heat exchanger 19 can be prevented. Also, if the water heat exchanger 19 is damaged and refrigerant enters the water circuit W, due to the pressure difference between the refrigerant circuit C and the water circuit W, the entered refrigerant will drop to a low temperature, posing a risk of freezing of the water flowing through the water circuit W. Therefore, by activating the heater when refrigerant leaks and raising the temperature of the water flowing through the water circuit W, freezing of the water in the water circuit W can be prevented.

[0076] Furthermore, the control unit 51 may keep the expansion valves 45A and / or 45B fully closed while the fan 61 is operating. This suppresses the movement of refrigerant flowing through the refrigerant circuit C, thereby suppressing the flow of refrigerant to the leak point and preventing further refrigerant leakage. In the configuration shown in Figure 4, where a check valve 18 is provided on the discharge side of the compressor 17, the refrigerant circuit C is not pressurized. In this case, for example, if the leak point is on the outdoor heat exchanger 30 side of the compressor 17 and also on the outdoor heat exchanger 30 side of the expansion valve 45B, closing the expansion valves 45A and / or 45B can suppress refrigerant leakage from the water heat exchanger 19 side by the expansion valves 45A, 45B and the check valve 18. Also, if the leak point is not near the receiver 80, keeping both expansion valves 45A and 45B fully closed can protect the receiver 80, which can store a large amount of refrigerant, and prevent refrigerant leakage.

[0077] [Modification 3] Next, Modification 3 of this embodiment will be described with reference to Figure 8. This modification differs from Modification 2 of the first embodiment in that step S125 is performed instead of step S121. Other points are the same as in Modification 2 of the first embodiment, so the same reference numerals are used for the same steps and their detailed description is omitted.

[0078] After step S108, the process proceeds to step S125. In step S125, the ambient temperature of the outdoor unit 1 and the refrigerant pressure in the water heat exchanger 19 are checked. The refrigerant pressure in the water heat exchanger 19 can be derived, for example, from the pressure of the suction pressure sensor 29. There may also be a pressure sensor between the water heat exchanger 19 and the receiver 80. Based on the ambient temperature of the outdoor unit 1, the refrigerant pressure in the water heat exchanger 19 can be estimated. If the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 corresponds to the refrigerant pressure value estimated from the ambient temperature, it can be determined that there is no refrigerant leakage. On the other hand, if the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 does not correspond to the refrigerant pressure value estimated from the ambient temperature, and there is a discrepancy, it cannot be determined that there is no refrigerant leakage, or it can be determined that there is a refrigerant leak.

[0079] If it cannot be determined in step S125 that there is no refrigerant leak, or if it is determined that there is a refrigerant leak, the process proceeds to step S123, and the fan 61 continues to rotate until it can be determined in step S125 that there is no refrigerant leak. The compressor 17 is also kept shut off.

[0080] If it is determined in step S125 that there is no refrigerant leak, the process proceeds to step S124, and the control unit 51 stops the rotation of the fan 61. At this time, the prohibition on starting the compressor 17 is released. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leaks into the outdoor unit 1.

[0081] This modified version provides the same effects as Modification 2 of the first embodiment described above. Furthermore, the outside temperature of the outdoor unit 1 and the pressure of the suction pressure sensor 29 can be obtained immediately after the outdoor unit 1 is turned ON. Therefore, since these can be obtained earlier than the refrigerant concentration detected by the refrigerant detection sensor 42, the control unit 51 can determine whether or not there is a refrigerant leak before the refrigerant detection sensor 42 is activated.

[0082] [Modification 4] Next, Modification 4 of this embodiment will be described with reference to Figure 9. This modification differs from the first embodiment in that step S126 is performed after step S104 and before step S105. Other points are the same as in the first embodiment, so the same reference numerals are used for similar steps and their detailed descriptions are omitted.

[0083] After step S108, the process proceeds to step S126. In step S126, the ambient temperature of the outdoor unit 1 and the refrigerant pressure in the water heat exchanger 19 are checked. The refrigerant pressure in the water heat exchanger 19 can be derived, for example, from the pressure of the suction pressure sensor 29. Based on the ambient temperature of the outdoor unit 1, the refrigerant pressure in the water heat exchanger 19 can be estimated. If the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 corresponds to the refrigerant pressure value estimated from the ambient temperature, it can be determined that there is no refrigerant leak. On the other hand, if the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 does not correspond to the refrigerant pressure value estimated from the ambient temperature, and there is a discrepancy, it cannot be determined that there is no refrigerant leak, or it can be determined that there is a refrigerant leak.

[0084] If it is determined in step S126 that there is no refrigerant leak, proceed to step S106 and start the outdoor unit 1 as usual.

[0085] If it cannot be determined in step S126 that there is no refrigerant leak, or if it can be determined that there is a leak, the process proceeds to step S105, where the control device 50 checks the presence or absence of refrigerant leak detection information in the storage unit 52.

[0086] This modified version provides the same effects as the first embodiment described above. Furthermore, the outside temperature of the outdoor unit 1 and the pressure of the suction pressure sensor 29 can be obtained immediately after the outdoor unit 1 is turned ON. Therefore, since these can be obtained earlier than the refrigerant concentration detected by the refrigerant detection sensor 42, the control unit 51 can determine whether or not there is a refrigerant leak before the refrigerant detection sensor 42 is activated.

[0087] [Second Embodiment] Next, an example of a control method by the control device of the outdoor unit according to the second embodiment will be described with reference to Figure 10. Figure 10 is a flowchart showing the control method by the control device 50 of the outdoor unit according to this embodiment. In this embodiment, the storage unit 52 stores refrigerant leak detection information when the concentration of refrigerant leaked into the outdoor unit 1 is above a certain level (when the concentration of refrigerant detected by the refrigerant detection sensor 42 is above a predetermined value). The storage unit 52 also stores the time when the refrigerant leak detection information was stored. The control unit 51 is configured not to start the rotation of the fan 61 if a certain amount of time has elapsed since the above time when the power of the outdoor unit 1 is turned ON.

[0088] Step S201 is the same as step S101, so its explanation is omitted. In step S202, the control device 50, which has received refrigerant leak detection information from the refrigerant detection sensor 42, detects an abnormality and displays an abnormality indicator on a monitor or the like. Accordingly, the control unit 51 controls the fan 61 to start rotating via the fan drive unit 62.

[0089] In step S203, the control device 50 writes (stores) refrigerant leak detection information to the storage unit (CPU) 52 (storage step) if the concentration of refrigerant leaked into the outdoor unit 1 is above a certain level (the concentration of refrigerant detected by the refrigerant detection sensor 42 is above a predetermined value). At this time, the storage unit 52 also stores the time when the refrigerant leak detection information was stored.

[0090] Step S204 is the same as step S103, and step S205 is the same as step S104. Therefore, their explanations are omitted.

[0091] In step S206, the control device 50 checks whether there is any refrigerant leak detection information in the storage unit 52. If there is no refrigerant leak detection information in the storage unit 52, the process proceeds to step S207 and the outdoor unit 1 is started as usual.

[0092] On the other hand, if there is refrigerant leak detection information in the memory unit 52, the process proceeds to step S208, where it is checked whether a certain amount of time has elapsed since the time when the refrigerant leak detection information was stored in the memory unit 52 in step S203. The certain amount of time is set to the time at which it is determined that the refrigerant has already been agitated inside the outdoor unit 1. If the certain amount of time has elapsed, the process proceeds to step S207, where the outdoor unit 1 is started as usual. On the other hand, if the certain amount of time has not elapsed, the process proceeds to step S209, where the fan 61 is started to rotate via the fan drive unit 62 under the control of the control unit 51 (control process). An abnormality is also displayed on a monitor or the like.

[0093] In step S210, the refrigerant detection sensor 42 is activated. Since it takes time to activate the refrigerant detection sensor 42, in this embodiment, the fan 61 is started to rotate before the refrigerant detection sensor 42 is activated.

[0094] In step S211, the refrigerant detection sensor 42 detects a refrigerant leak into the outdoor unit 1, and the control device 50 determines whether or not there is a refrigerant leak. If it is determined in step S211 that there is a refrigerant leak, the process proceeds to step S212 and the fan 61 continues to rotate. After a predetermined time has elapsed since the determination of whether or not there is a refrigerant leak, the detection by the refrigerant detection sensor 42 and the determination by the control device 50 are performed again. In this way, steps S211 to S212 are repeated until it is determined in step S211 that there is no refrigerant leak.

[0095] If it is determined in step S211 that there is no refrigerant leak, the process proceeds to step S213, where the control unit 51 stops the rotation of the fan 61. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started up as usual.

[0096] As described above, this embodiment provides the following effects. In the control device 50 of the outdoor unit 1 of this embodiment, the storage unit 52 stores information that a refrigerant leak has been detected when the concentration of refrigerant leaked into the outdoor unit 1 is above a certain level. That is, if the concentration of refrigerant leaked into the outdoor unit 1 is below a certain level, the risk of ignition is small, so the storage unit 52 can be configured not to store information that a refrigerant leak has been detected. As a result, the fan 61 can be configured not to be turned when the risk of ignition is small, and the fan 61 can be turned at a more necessary time. Therefore, power consumption can be suppressed while more reliably reducing the risk of ignition due to refrigerant leakage.

[0097] Even if the memory unit 52 stores information that it has detected a refrigerant leak, if a certain amount of time has elapsed since the time the information about the refrigerant leak was stored when the power to the outdoor unit 1 is turned ON, the refrigerant may already be agitated inside the outdoor unit 1. In this case, since the risk of ignition is small, the control unit 51 can be configured not to start the rotation of the fan 61. In other words, in this case, the outdoor unit 1 is started as usual. Therefore, power consumption can be suppressed while more reliably reducing the risk of ignition due to refrigerant leakage.

[0098] [Modification 1] Next, Modification 1 of this embodiment will be described with reference to Figure 11. In this modification, instead of determining whether or not there is a refrigerant leak based on the detection result of the refrigerant detection sensor 42 in step S211, it is confirmed in step S221 whether a predetermined time has elapsed since the fan 61 started rotating, which is different from the second embodiment. Other points are the same as in the second embodiment, so the same reference numerals are used for the same steps and their detailed explanation is omitted.

[0099] After step S210, the process proceeds to step S221. In step S221, it is checked whether a predetermined time has elapsed since the fan 61 started rotating. The predetermined time is set to the time at which it is considered that no area will reach the ignition concentration around the outdoor unit 1, even if the entire amount of refrigerant flowing through the refrigerant circuit C leaks slowly. Slow leak refers to the lowest leakage rate at which the local concentration of refrigerant mixed with the surrounding environment around the outdoor unit 1 can reach the ignition concentration when refrigerant leaks. The predetermined time can be calculated based on the total amount of refrigerant and the minimum leakage rate mentioned above. If the predetermined time for ending refrigerant suction is determined assuming that the refrigerant leaks at high speed, the fan 61 will stop rotating while the refrigerant leak is still continuing if the refrigerant leaks slowly. In this case, there is a risk that an area will be created around the outdoor unit where the refrigerant concentration exceeds the ignition concentration. On the other hand, by determining the predetermined time assuming that the refrigerant leaks slowly, it is possible to reliably prevent the creation of an area that reaches the ignition concentration around the outdoor unit 1, not only in the case of high-speed leakage but also in the case of slow leakage.

[0100] If the predetermined time has not elapsed in step S221, the process proceeds to step S212, and the fan 61 continues to rotate until the predetermined time has elapsed.

[0101] If a predetermined time has elapsed in step S221, the process proceeds to step S213, where the control unit 51 stops the rotation of the fan 61. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leakage into the outdoor unit 1.

[0102] This modified version achieves the same effects as the second embodiment described above. In this modified version, the control unit 51 stops the rotation of the fan 61 after a predetermined time has elapsed since the fan 61 started rotating. By rotating the fan 61, even if refrigerant leakage occurs, the area around the outdoor unit 1 that reaches the ignition concentration can be reliably narrowed. Therefore, the installation restrictions around the outdoor unit 1 can be relaxed, which is advantageous in terms of installation restrictions. The predetermined time is set to a time when, even assuming that the entire amount of refrigerant flowing through the refrigerant circuit C is slowly leaking, an area that reaches the ignition concentration around the outdoor unit 1 is expected to disappear.

[0103] [Modification 2] Next, Modification 2 of this embodiment will be described with reference to Figure 12. This modification differs from Modification 1 of the second embodiment in that step S222 is performed instead of step S209, step S223 is performed instead of step S212, and step S224 is performed instead of step S213. Other points are the same as Modification 1 of the second embodiment, so the same reference numerals are used for the same steps and their detailed description is omitted.

[0104] If a certain amount of time has not elapsed in step S208, the process proceeds to step S222, where the control unit 51 immediately starts the rotation of the fan 61 via the fan drive unit 62. At this time, the control unit 51 performs a control to prevent the compressor 17 from starting. It also displays an error message on a monitor or the like.

[0105] Step S210 is the same as in the second embodiment, so its description is omitted. After step S210, the process proceeds to step S221. In step S221, it is checked whether a predetermined time has elapsed since the fan 61 started rotating. If the predetermined time has not elapsed in step S221, the process proceeds to step S223, and the fan 61 continues to rotate until the predetermined time has elapsed. The compressor 17 is also kept shut off.

[0106] If a predetermined time has elapsed in step S221, the process proceeds to step S224, where the control unit 51 stops the rotation of the fan 61. At this time, the prohibition on starting the compressor 17 is released. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leakage into the outdoor unit 1.

[0107] This modified version provides the same effects as Modification 1 of the second embodiment described above. Furthermore, it prevents the compressor 17 from starting up while refrigerant is leaking inside the outdoor unit 1. This reliably reduces the risk of ignition caused by the starting of the compressor 17.

[0108] In this modified example, the compressor 17 was disabled in step S222. However, instead of disabling the compressor 17, another control mechanism may be used to reduce the risk of ignition. For example, the water pump 75 may be disabled. This prevents refrigerant from leaking into the room via water by keeping the water pump 75 in the OFF state, for example, if the water heat exchanger 19 is damaged and refrigerant is leaking. At this time, the remote control displays that the water pump 75 is OFF and the fan is operating. In other words, it notifies the user of the control status of the outdoor unit 1.

[0109] The control unit 51 can also control the flow direction of the three-way valve 81 in the water circuit W from the direction of the indoor unit to the direction of the water tank 82. This prevents leaked refrigerant from flowing into the indoor unit side via water.

[0110] A heater (not shown) may be provided between the water heat exchanger 19 and the three-way valve 81 in the water circuit W, and the control unit 51 may activate this heater. If refrigerant leaks from the refrigerant circuit C, the temperature of the refrigerant circuit C will drop, causing the water on the water circuit W side of the water heat exchanger 19 to freeze, which poses a risk of damage to the water heat exchanger 19. Therefore, by activating the heater when refrigerant leaks and raising the temperature of the water flowing through the water circuit W, freezing of the water in the water heat exchanger 19 can be prevented. Also, if the water heat exchanger 19 is damaged and refrigerant enters the water circuit W, due to the pressure difference between the refrigerant circuit C and the water circuit W, the entered refrigerant will drop to a low temperature, posing a risk of freezing of the water flowing through the water circuit W. Therefore, by activating the heater when refrigerant leaks and raising the temperature of the water flowing through the water circuit W, freezing of the water in the water circuit W can be prevented.

[0111] Furthermore, the control unit 51 may keep the expansion valves 45A and / or 45B fully closed while the fan 61 is operating. This suppresses the movement of refrigerant flowing through the refrigerant circuit C, thereby suppressing the flow of refrigerant to the leak point and preventing further refrigerant leakage. In the configuration shown in Figure 4, where a check valve 18 is provided on the discharge side of the compressor 17, the refrigerant circuit C is not pressurized. In this case, for example, if the leak point is on the outdoor heat exchanger 30 side of the compressor 17 and also on the outdoor heat exchanger 30 side of the expansion valve 45B, closing the expansion valves 45A and / or 45B can suppress refrigerant leakage from the water heat exchanger 19 side by the expansion valves 45A, 45B and the check valve 18. Also, if the leak point is not near the receiver 80, keeping both expansion valves 45A and 45B fully closed can protect the receiver 80, which can store a large amount of refrigerant, and prevent refrigerant leakage.

[0112] [Modification 3] Next, Modification 3 of this embodiment will be described with reference to Figure 13. This modification differs from Modification 2 of the second embodiment in that step S225 is performed instead of step S221. Other points are the same as in Modification 2 of the second embodiment, so the same reference numerals are used for the same steps and their detailed description is omitted.

[0113] After step S210, the process proceeds to step S225. In step S225, the ambient temperature of the outdoor unit 1 and the refrigerant pressure in the water heat exchanger 19 are checked. The refrigerant pressure in the water heat exchanger 19 can be derived, for example, from the pressure of the suction pressure sensor 29. There may also be a pressure sensor between the water heat exchanger 19 and the receiver 80. Based on the ambient temperature of the outdoor unit 1, the refrigerant pressure in the water heat exchanger 19 can be estimated. If the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 corresponds to the refrigerant pressure value estimated from the ambient temperature, it can be determined that there is no refrigerant leakage. On the other hand, if the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 does not correspond to the refrigerant pressure value estimated from the ambient temperature, and there is a discrepancy, it cannot be determined that there is no refrigerant leakage, or it can be determined that there is a refrigerant leak.

[0114] If it cannot be determined in step S225 that there is no refrigerant leak, or if it is determined that there is a refrigerant leak, the process proceeds to step S223, and the fan 61 continues to rotate until it can be determined in step S225 that there is no refrigerant leak. The compressor 17 is also kept shut off.

[0115] If it is determined in step S225 that there is no refrigerant leak, the process proceeds to step S224, and the control unit 51 stops the rotation of the fan 61. At this time, the prohibition on starting the compressor 17 is released. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leaks into the outdoor unit 1.

[0116] This modified version provides the same effects as Modification 2 of the second embodiment described above. Furthermore, the outside temperature of the outdoor unit 1 and the pressure of the suction pressure sensor 29 can be obtained immediately after the outdoor unit 1 is turned ON. Therefore, since these can be obtained earlier than the refrigerant concentration detected by the refrigerant detection sensor 42, the control unit 51 can determine whether or not there is a refrigerant leak before the refrigerant detection sensor 42 is activated.

[0117] [Modification 4] Next, Modification 4 of this embodiment will be described with reference to Figure 14. This modification differs from the second embodiment in that step S226 is performed after step S205 and before step S206. Other points are the same as in the second embodiment, so the same reference numerals are used for similar steps and their detailed descriptions are omitted.

[0118] After step S205, the process proceeds to step S226. In step S226, the ambient temperature of the outdoor unit 1 and the refrigerant pressure in the water heat exchanger 19 are checked. The refrigerant pressure in the water heat exchanger 19 can be derived, for example, from the pressure of the suction pressure sensor 29. Based on the ambient temperature of the outdoor unit 1, the refrigerant pressure in the water heat exchanger 19 can be estimated. If the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 corresponds to the refrigerant pressure value estimated from the ambient temperature, it can be determined that there is no refrigerant leak. On the other hand, if the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 does not correspond to the refrigerant pressure value estimated from the ambient temperature, and there is a discrepancy, it cannot be determined that there is no refrigerant leak, or it can be determined that there is a refrigerant leak.

[0119] If it is determined in step S226 that there is no refrigerant leak, proceed to step S207 and start the outdoor unit 1 as usual.

[0120] If it cannot be determined in step S226 that there is no refrigerant leak, or if it can be determined that there is a leak, the process proceeds to step S206, where the control device 50 checks the presence or absence of refrigerant leak detection information in the storage unit 52.

[0121] This modified version provides the same effects as the second embodiment described above. Furthermore, the outside temperature of the outdoor unit 1 and the pressure of the suction pressure sensor 29 can be obtained immediately after the outdoor unit 1 is turned ON. Therefore, since these can be obtained earlier than the refrigerant concentration detected by the refrigerant detection sensor 42, the control unit 51 can determine whether or not there is a refrigerant leak before the refrigerant detection sensor 42 is activated.

[0122] [Third Embodiment] Next, an example of a control method by the control device of the outdoor unit according to the third embodiment will be described with reference to Figure 15. Figure 15 is a flowchart showing the control method by the control device 50 of the outdoor unit according to this embodiment. In this embodiment, the control unit 51 starts rotating the fan 61 when the power to the outdoor unit 1 is turned ON. That is, in this embodiment, the control unit 51 starts rotating the fan 61 immediately when the power to the outdoor unit 1 is turned ON, without relying on refrigerant leak detection information from the refrigerant detection sensor 42. Therefore, in this embodiment, the storage unit 52 in the first and second embodiments is not an essential component.

[0123] In step S301, the power to the outdoor unit 1 is turned ON. In step S302, the control unit 51 controls the fan 61 to start rotating via the fan drive unit 62 (control step). In other words, in this embodiment, the control unit 51 immediately starts the fan 61 to rotate without relying on refrigerant leak detection information from the refrigerant detection sensor 42.

[0124] In step S303, the refrigerant detection sensor 42 is activated. Since it takes time to activate the refrigerant detection sensor 42, in this embodiment, the fan 61 is started to rotate before the refrigerant detection sensor 42 is activated.

[0125] In step S304, the refrigerant detection sensor 42 detects a refrigerant leak into the outdoor unit 1, and the control device 50 determines whether or not there is a refrigerant leak. If a refrigerant leak is determined to be present in step S304, the process proceeds to step S305, and the fan 61 continues to rotate. Accordingly, the control device 50 displays an abnormality indicator on a monitor or the like. After a predetermined time has elapsed since the determination of whether or not there is a refrigerant leak, the detection by the refrigerant detection sensor 42 and the determination by the control device 50 are performed again. In this manner, steps S304 to S305 are repeated until it is determined that there is no refrigerant leak in step S304.

[0126] If it is determined in step S304 that there is no refrigerant leak, the process proceeds to step S306, where the control unit 51 stops the rotation of the fan 61. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual.

[0127] As described above, this embodiment provides the following effects. In the control device 50 of the outdoor unit 1 of this embodiment, the control unit 51 starts rotating the fan 61 when the power to the outdoor unit 1 is turned ON. In this way, the control device 50 of this embodiment rotates the fan regardless of whether or not there is a refrigerant leak into the outdoor unit 1, thus reliably reducing the risk of ignition due to a refrigerant leak into the outdoor unit 1.

[0128] Furthermore, in the control method for the outdoor unit 1 of this embodiment, the fan 61 starts rotating when the power to the outdoor unit 1 is turned ON during the control process. In this way, the control method of this embodiment rotates the fan regardless of whether or not there is a refrigerant leak into the outdoor unit 1, thus reliably reducing the risk of ignition due to a refrigerant leak into the outdoor unit 1.

[0129] [Modification 1] Next, Modification 1 of this embodiment will be described with reference to Figure 16. In this modification, instead of determining whether or not there is a refrigerant leak based on the detection result of the refrigerant detection sensor 42 in step S304, the presence or absence of a predetermined time has elapsed since the fan 61 started rotating is confirmed in step S321, which is different from the third embodiment. Other points are the same as in the third embodiment, so the same reference numerals are used for the same steps and their detailed explanation is omitted.

[0130] After step S303, the process proceeds to step S321. In step S321, it is checked whether a predetermined time has elapsed since the fan 61 started rotating. The predetermined time is set to a time at which, even if the entire amount of refrigerant flowing through the refrigerant circuit C leaks slowly, it is considered that no area around the outdoor unit 1 will reach the ignition concentration. Slow leak refers to the lowest leakage rate at which, when refrigerant leaks, the local concentration of refrigerant mixed with the surrounding environment around the outdoor unit 1 can reach the ignition concentration. The predetermined time can be calculated based on the total amount of refrigerant and the minimum leakage rate mentioned above. If the predetermined time for ending refrigerant suction is determined assuming that the refrigerant leaks at high speed, then if the refrigerant leaks slowly, the fan 61 will stop rotating while the refrigerant leak is still continuing. In this case, there is a risk that an area around the outdoor unit will reach a refrigerant concentration higher than the ignition concentration. On the other hand, by determining the predetermined time assuming that the refrigerant leaks slowly, it is possible to reliably prevent the occurrence of an area around the outdoor unit 1 that reaches the ignition concentration not only when the refrigerant leaks at high speed but also when it leaks slowly.

[0131] If the predetermined time has not elapsed in step S321, the process proceeds to step S305, and the fan 61 continues to rotate until the predetermined time has elapsed.

[0132] If a predetermined time has elapsed in step S321, the process proceeds to step S306, where the control unit 51 stops the rotation of the fan 61. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leakage into the outdoor unit 1.

[0133] This modified version achieves the same effects as the third embodiment described above. In this modified version, the control unit 51 stops the rotation of the fan 61 after a predetermined time has elapsed since the fan 61 started rotating. By rotating the fan 61, even if refrigerant leakage occurs, the area around the outdoor unit 1 that reaches the ignition concentration can be reliably narrowed. Therefore, the installation restrictions around the outdoor unit 1 can be relaxed, which is advantageous in terms of installation restrictions. The predetermined time is set to a time when, even assuming that the entire amount of refrigerant flowing through the refrigerant circuit C is slowly leaking, an area that reaches the ignition concentration around the outdoor unit 1 is no longer expected to occur.

[0134] [Modification 2] Next, Modification 2 of this embodiment will be described with reference to Figure 17. This modification differs from Modification 1 of the third embodiment in that step S322 is performed instead of step S302, step S323 is performed instead of step S305, and step S324 is performed instead of step S306. Other points are the same as in Modification 1 of the third embodiment, so the same reference numerals are used for the same steps and their detailed description is omitted.

[0135] After step S301, the system proceeds to step S322, where the control unit 51 immediately starts the rotation of the fan 61 via the fan drive unit 62. At this time, the control unit 51 performs a control to prevent the compressor 17 from starting. It also displays an error message on a monitor or the like.

[0136] Step S303 is the same as in the first embodiment, so its description is omitted. After step S303, the process proceeds to step S321. In step S321, it is checked whether a predetermined time has elapsed since the fan 61 started rotating. If the predetermined time has not elapsed in step S321, the process proceeds to step S323, and the fan 61 continues to rotate until the predetermined time has elapsed. The compressor 17 is also kept shut off.

[0137] If a predetermined time has elapsed in step S321, the process proceeds to step S324, where the control unit 51 stops the rotation of the fan 61. At this time, the prohibition on starting the compressor 17 is released. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any leakage of refrigerant into the outdoor unit 1.

[0138] This modified version provides the same effects as Modification 1 of the third embodiment described above. Furthermore, it prevents the compressor 17 from starting up while refrigerant is leaking inside the outdoor unit 1. This reliably reduces the risk of ignition caused by the starting of the compressor 17.

[0139] In this modified example, the compressor 17 was disabled in step S122. However, instead of disabling the compressor 17, another control mechanism may be used to reduce the risk of ignition. For example, the water pump 75 may be disabled. This prevents refrigerant from leaking into the room via water by keeping the water pump 75 in the OFF state, for example, if the water heat exchanger 19 is damaged and refrigerant is leaking. At this time, the remote control displays that the water pump 75 is OFF and the fan is operating. In other words, it notifies the user of the control status of the outdoor unit 1.

[0140] The control unit 51 can also control the flow direction of the three-way valve 81 in the water circuit W from the direction of the indoor unit to the direction of the water tank 82. This prevents leaked refrigerant from flowing into the indoor unit side via water.

[0141] A heater (not shown) may be provided between the water heat exchanger 19 and the three-way valve 81 in the water circuit W, and the control unit 51 may activate this heater. If refrigerant leaks from the refrigerant circuit C, the temperature of the refrigerant circuit C will drop, causing the water on the water circuit W side of the water heat exchanger 19 to freeze, which poses a risk of damage to the water heat exchanger 19. Therefore, by activating the heater when refrigerant leaks and raising the temperature of the water flowing through the water circuit W, freezing of the water in the water heat exchanger 19 can be prevented. Also, if the water heat exchanger 19 is damaged and refrigerant enters the water circuit W, due to the pressure difference between the refrigerant circuit C and the water circuit W, the entered refrigerant will drop to a low temperature, posing a risk of freezing of the water flowing through the water circuit W. Therefore, by activating the heater when refrigerant leaks and raising the temperature of the water flowing through the water circuit W, freezing of the water in the water circuit W can be prevented.

[0142] Furthermore, the control unit 51 may keep the expansion valves 45A and / or 45B fully closed while the fan 61 is operating. This suppresses the movement of refrigerant flowing through the refrigerant circuit C, thereby suppressing the flow of refrigerant to the leak point and preventing further refrigerant leakage. In the configuration shown in Figure 4, where a check valve 18 is provided on the discharge side of the compressor 17, the refrigerant circuit C is not pressurized. In this case, for example, if the leak point is on the outdoor heat exchanger 30 side of the compressor 17 and also on the outdoor heat exchanger 30 side of the expansion valve 45B, closing the expansion valves 45A and / or 45B can suppress refrigerant leakage from the water heat exchanger 19 side by the expansion valves 45A, 45B and the check valve 18. Also, if the leak point is not near the receiver 80, keeping both expansion valves 45A and 45B fully closed can protect the receiver 80, which can store a large amount of refrigerant, and prevent refrigerant leakage.

[0143] [Modification 3] Next, Modification 3 of this embodiment will be described with reference to Figure 18. This modification differs from Modification 2 of the third embodiment in that step S325 is performed instead of step S321. Other points are the same as in Modification 2 of the third embodiment, so the same reference numerals are used for the same steps and their detailed description is omitted.

[0144] After step S303, the process proceeds to step S325. In step S325, the ambient temperature of the outdoor unit 1 and the refrigerant pressure in the water heat exchanger 19 are checked. The refrigerant pressure in the water heat exchanger 19 can be derived, for example, from the pressure of the suction pressure sensor 29. There may also be a pressure sensor between the water heat exchanger 19 and the receiver 80. Based on the ambient temperature of the outdoor unit 1, the refrigerant pressure in the water heat exchanger 19 can be estimated. If the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 corresponds to the refrigerant pressure value estimated from the ambient temperature, it can be determined that there is no refrigerant leak. On the other hand, if the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 does not correspond to the refrigerant pressure value estimated from the ambient temperature, and there is a discrepancy, it cannot be determined that there is no refrigerant leak, or it can be determined that there is a refrigerant leak.

[0145] If it cannot be determined in step S325 that there is no refrigerant leak, or if it is determined that there is a refrigerant leak, the process proceeds to step S323, and the fan 61 continues to rotate until it can be determined in step S325 that there is no refrigerant leak. The compressor 17 is also kept shut off.

[0146] If it is determined in step S325 that there is no refrigerant leak, the process proceeds to step S324, where the control unit 51 stops the rotation of the fan 61. At this time, the prohibition on starting the compressor 17 is released. The control device 50 also turns off any abnormality indicators displayed on the monitor, etc. After that, the outdoor unit 1 is started as usual. After the outdoor unit 1 is started, the refrigerant detection sensor 42 appropriately detects any refrigerant leaks into the outdoor unit 1.

[0147] This modified version provides the same effects as Modification 2 of the third embodiment described above. Furthermore, the outside temperature of the outdoor unit 1 and the pressure of the suction pressure sensor 29 can be obtained immediately after the outdoor unit 1 is turned ON. Therefore, since these can be obtained earlier than the refrigerant concentration detected by the refrigerant detection sensor 42, the control unit 51 can determine whether or not there is a refrigerant leak before the refrigerant detection sensor 42 is activated.

[0148] [Modification 4] Next, Modification 4 of this embodiment will be described with reference to Figure 19. This modification differs from the third embodiment in that step S326 is performed after step S301 and before step S302. Other points are the same as in the third embodiment, so the same reference numerals are used for similar steps and their detailed descriptions are omitted.

[0149] After step S301, the process proceeds to step S326. In step S326, the ambient temperature of the outdoor unit 1 and the refrigerant pressure in the water heat exchanger 19 are checked. The refrigerant pressure in the water heat exchanger 19 can be derived, for example, from the pressure of the suction pressure sensor 29. Based on the ambient temperature of the outdoor unit 1, the refrigerant pressure in the water heat exchanger 19 can be estimated. If the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 corresponds to the refrigerant pressure value estimated from the ambient temperature, it can be determined that there is no refrigerant leak. On the other hand, if the refrigerant pressure value derived from the pressure of the suction pressure sensor 29 does not correspond to the refrigerant pressure value estimated from the ambient temperature, and there is a discrepancy, it cannot be determined that there is no refrigerant leak, or it can be determined that there is a refrigerant leak.

[0150] If it is determined in step S326 that there is no refrigerant leak, proceed to step S327 and start the outdoor unit 1 as usual.

[0151] If it cannot be determined in step S326 that there is no refrigerant leak, or if it is determined that there is a leak, the process proceeds to step S302, where the control unit 51 controls the fan 61 to start rotating via the fan drive unit 62.

[0152] This modified version provides the same effects as the third embodiment described above. Furthermore, the outside temperature of the outdoor unit 1 and the pressure of the suction pressure sensor 29 can be obtained immediately after the outdoor unit 1 is turned ON. Therefore, since these can be obtained earlier than the refrigerant concentration detected by the refrigerant detection sensor 42, the control unit 51 can determine whether or not there is a refrigerant leak before the refrigerant detection sensor 42 is activated.

[0153] <Note> The control device for the outdoor unit described in the embodiments described above can be understood, for example, as follows. The control device for the outdoor unit (50) according to the first aspect of this disclosure comprises a control unit (51) that controls the rotation of a fan (61) provided on the outdoor unit (1), and a storage unit (52) that stores information that a refrigerant leak has been detected from a refrigerant detection sensor (42) that detects the leakage of refrigerant into the outdoor unit, wherein the control unit starts the rotation of the fan when the power to the outdoor unit is turned ON and the storage unit has stored information that a refrigerant leak has been detected from the refrigerant detection sensor.

[0154] The outdoor unit control device of this disclosure includes a storage unit that stores information about refrigerant leakage detected by a refrigerant detection sensor that detects refrigerant leakage into the outdoor unit. Therefore, if the refrigerant detection sensor detects refrigerant leakage, the storage unit can store the information about the detected refrigerant leakage even if the outdoor unit's power is turned OFF. Furthermore, in the outdoor unit control device of this disclosure, the control unit starts the fan rotation when the outdoor unit's power is turned ON and the storage unit has stored information about refrigerant leakage detected by the refrigerant detection sensor. Therefore, if refrigerant leakage is detected before the outdoor unit's power is turned OFF and there is a risk of ignition due to the refrigerant leakage, the fan rotation can be started quickly. This reliably reduces the risk of ignition due to refrigerant leakage into the outdoor unit.

[0155] In the first embodiment, the control device for an outdoor unit according to a second aspect of the present disclosure stores information that a refrigerant leak has been detected when the concentration of the refrigerant leaked into the outdoor unit is above a certain level.

[0156] In the outdoor unit control device of this disclosure, the memory unit stores information detecting a refrigerant leak when the concentration of refrigerant leaked into the outdoor unit is above a certain level. That is, if the concentration of refrigerant leaked into the outdoor unit is below a certain level, the risk of ignition is small, so the memory unit can be configured not to store information detecting a refrigerant leak. This allows the fan to not be turned on when the risk of ignition is small, and the fan to be turned on at a more necessary time. Therefore, power consumption can be suppressed while more reliably reducing the risk of ignition due to refrigerant leaks.

[0157] In the third aspect of the present disclosure, the control device for an outdoor unit, in the first or second aspect, stores the time when it stores information that it has detected a refrigerant leak, and the control unit does not start rotating the fan if a certain amount of time has elapsed from the time when the power of the outdoor unit is turned ON.

[0158] Even if the memory unit stores information that a refrigerant leak has been detected, if a certain amount of time has passed since the time the refrigerant leak was detected and stored when the outdoor unit's power is turned on, the refrigerant may already be agitated inside the outdoor unit. In this case, since the risk of ignition is small, the control unit can be configured not to start rotating the fan as described above. In other words, in this case, the outdoor unit starts up as usual. Therefore, power consumption can be suppressed while more reliably reducing the risk of ignition due to refrigerant leakage.

[0159] A control device for an outdoor unit according to a fourth aspect of this disclosure includes a control unit that controls the rotation of a fan provided on the outdoor unit, and the control unit starts the rotation of the fan when the power to the outdoor unit is turned ON.

[0160] In the outdoor unit control device of this disclosure, the control unit starts the fan rotating when the power to the outdoor unit is turned ON. In this way, the control device of this disclosure rotates the fan regardless of whether or not there is a refrigerant leak into the outdoor unit, thereby reliably reducing the risk of ignition due to a refrigerant leak into the outdoor unit.

[0161] In the control device for an outdoor unit according to the fifth aspect of this disclosure, in any of the first to fourth aspects, the control unit stops the rotation of the fan after a predetermined time has elapsed since the fan started rotating.

[0162] In the outdoor unit control device of this disclosure, the control unit stops the fan rotation after a predetermined time has elapsed since the fan started rotating. By rotating the fan, even if refrigerant leakage occurs, the area around the outdoor unit that can reach the ignition concentration can be reliably narrowed. Therefore, the installation restrictions around the outdoor unit can be relaxed, which is advantageous in terms of installation restrictions.

[0163] In the control device for an outdoor unit according to the sixth aspect of the present disclosure, in any of the first to fourth aspects, the control unit controls an outdoor unit comprising: a compressor for compressing the refrigerant; a refrigerant circuit through which the refrigerant discharged from the compressor circulates; an outdoor heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and outside air; a heat transfer medium heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and a liquid heat transfer medium; and a heat transfer medium circuit for sending the heat transfer medium, which has been heat-exchanged in the heat transfer medium heat exchanger, to a heat utilization destination. The control unit prohibits the starting of the compressor when the fan starts rotating after the power to the outdoor unit is turned ON.

[0164] The outdoor unit control device described in this disclosure prevents the compressor from starting up while refrigerant is leaking inside the outdoor unit. This significantly reduces the risk of ignition caused by the compressor starting up.

[0165] In the control device for an outdoor unit according to the seventh aspect of this disclosure, in the sixth aspect, the control unit stops the rotation of the fan after it has started rotating the fan, if it can determine that there is no leakage of refrigerant into the outdoor unit based on the outside temperature of the outdoor unit and the refrigerant pressure of the heat transfer medium heat exchanger.

[0166] In the outdoor unit control device of this disclosure, the outdoor temperature and the pressure from the suction pressure sensor of the outdoor unit can be acquired immediately after the outdoor unit is turned ON. Therefore, since these can be acquired earlier than the refrigerant concentration detected by the refrigerant detection sensor, the control unit can determine whether or not there is a refrigerant leak before the refrigerant detection sensor is activated.

[0167] In the control device for an outdoor unit according to the eighth aspect of the present disclosure, in any of the first to fourth aspects, the control unit controls an outdoor unit comprising: a compressor for compressing the refrigerant; a refrigerant circuit through which the refrigerant discharged from the compressor circulates; an outdoor heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and outside air; a heat transfer medium heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and a liquid heat transfer medium; and a heat transfer medium circuit for sending the heat transfer medium, which has been heat-exchanged in the heat transfer medium heat exchanger, to a heat utilization destination. The control unit determines whether or not there is a leak of refrigerant into the outdoor unit based on the outside temperature of the outdoor unit and the refrigerant pressure of the heat transfer medium heat exchanger, after the power to the outdoor unit is turned ON and before the fan starts rotating.

[0168] In the outdoor unit control device of this disclosure, the outdoor temperature and the pressure from the suction pressure sensor of the outdoor unit can be acquired immediately after the outdoor unit is turned ON. Therefore, since these can be acquired earlier than the refrigerant concentration detected by the refrigerant detection sensor, the control unit can determine whether or not there is a refrigerant leak before the refrigerant detection sensor is activated.

[0169] The outdoor unit according to the ninth aspect of this disclosure comprises a fan, a refrigerant detection sensor for detecting refrigerant leakage into the interior, and a control device for the outdoor unit according to any of the first to eighth aspects.

[0170] Since the outdoor unit of this disclosure is equipped with the control device described above, the risk of ignition due to refrigerant leakage into the outdoor unit can be reliably reduced.

[0171] A heat pump system according to the tenth aspect of this disclosure comprises an outdoor unit, a fan provided on the outdoor unit, a refrigerant detection sensor provided on the outdoor unit for detecting refrigerant leakage into the outdoor unit, a control device for the outdoor unit provided on the outdoor unit according to any of the first to eighth aspects, and a heat utilization unit connected to the outdoor unit.

[0172] The heat pump system of this disclosure is equipped with the control device described above, and therefore the risk of ignition due to refrigerant leakage into the outdoor unit can be reliably reduced.

[0173] A control method for an outdoor unit according to an eleventh aspect of the present disclosure is a control method for an outdoor unit comprising a fan and a refrigerant detection sensor for detecting refrigerant leakage into the unit, comprising a control step for controlling the rotation of the fan and a storage step for storing information that the refrigerant leakage from the refrigerant detection sensor has been detected, wherein in the control step, when the power of the outdoor unit is turned ON, the storage step has stored information that the refrigerant leakage from the refrigerant detection sensor has been detected, the rotation of the fan is started.

[0174] The outdoor unit control method of this disclosure includes a storage step that stores information about refrigerant leakage detected by a refrigerant detection sensor that detects refrigerant leakage into the outdoor unit. Therefore, if the refrigerant detection sensor detects refrigerant leakage, the information about the detected refrigerant leakage can be stored in the storage step even if the power to the outdoor unit is turned OFF. Furthermore, in the control method of this disclosure, if the information about refrigerant leakage detected by the refrigerant detection sensor is stored in the storage step when the power to the outdoor unit is turned ON, the fan starts rotating. Therefore, if refrigerant leakage is detected before the power to the outdoor unit is turned OFF and there is a risk of ignition due to refrigerant leakage, the fan can be started rotating quickly. This reliably reduces the risk of ignition due to refrigerant leakage into the outdoor unit.

[0175] A control method for an outdoor unit according to a twelfth aspect of the present disclosure is a control method for an outdoor unit comprising a fan and a refrigerant detection sensor for detecting refrigerant leakage into the unit, the method comprising a control step for controlling the rotation of the fan, wherein in the control step, the rotation of the fan is started when the power to the outdoor unit is turned ON.

[0176] In the outdoor unit control method of this disclosure, the fan starts rotating when the power to the outdoor unit is turned ON during the control process. In this way, the control method of this disclosure rotates the fan regardless of whether or not there is a refrigerant leak into the outdoor unit, thus reliably reducing the risk of ignition due to a refrigerant leak into the outdoor unit.

[0177] 1 Outdoor unit 3 Housing 4 Base 4a Base legs 4b Flat plate section 5 Fan room 7 Machine room 9 Partition wall 11 Fan opening 13 Sub-base 15 Sub-base support member 17 Compressor 17a Compressor legs 18 Check valve 19 Water heat exchanger 21 Gas separator 21a Discharge section 21b Water relief outlet 23 Control box 25 Water supply piping 26 Water return piping 28 Accumulator 29 Suction pressure sensor 30 Outdoor heat exchanger 34 Refrigerant discharge hole 40 Mesh 42 Refrigerant detection sensor 45A, 45B Expansion valve 46 Water connection pipe 47 Discharge pipe 49 Four-way valve (switching valve) 50 Control device 51 Control unit 52 Memory unit 61 Fan (outdoor fan) 62 Fan drive unit 71 Liquid refrigerant piping 73 Liquid pipe temperature sensor 75 Water pump (heat transfer pump) 77 Water inlet temperature sensor 79 Water outlet temperature sensor 80 Receiver 81 Three-way valve 82 Water tank C Refrigerant circuit W Water circuit (heat transfer circuit)

Claims

1. A control device for an outdoor unit comprising: a control unit that controls the rotation of a fan provided on the outdoor unit; and a storage unit that stores information about the detection of refrigerant leakage from a refrigerant detection sensor that detects refrigerant leakage into the outdoor unit, wherein the control unit starts the rotation of the fan when the power to the outdoor unit is turned ON and the storage unit has stored information about the detection of refrigerant leakage from the refrigerant detection sensor.

2. The control device for an outdoor unit according to claim 1, wherein the storage unit stores information indicating that a leak of the refrigerant has been detected when the concentration of the refrigerant leaked into the outdoor unit is above a certain level.

3. The control device for an outdoor unit according to claim 1, wherein the storage unit stores the time when it stores information that it has detected a refrigerant leak, and the control unit does not start the rotation of the fan if a certain amount of time has elapsed from the time when the power of the outdoor unit is turned ON.

4. A control unit for an outdoor unit, comprising a control unit for controlling the rotation of a fan installed on the outdoor unit, wherein the control unit starts the rotation of the fan when the power to the outdoor unit is turned ON.

5. The control device for an outdoor unit according to claim 4, wherein the control unit stops the rotation of the fan after a predetermined time has elapsed since the fan started rotating.

6. The control unit controls an outdoor unit comprising: a compressor for compressing a refrigerant; a refrigerant circuit through which the refrigerant discharged from the compressor circulates; an outdoor heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and outside air; a heat transfer medium heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and a liquid heat transfer medium; and a heat transfer medium circuit for sending the heat transfer medium, which has been heat-exchanged in the heat transfer medium heat exchanger, to a heat utilization destination; and the control unit prohibits starting the compressor when the fan starts rotating after the power to the outdoor unit is turned ON, as described in claim 4.

7. The control unit, after starting the rotation of the fan, stops the rotation of the fan if it can determine, based on the outside temperature of the outdoor unit and the refrigerant pressure of the heat transfer medium heat exchanger, that there is no leakage of refrigerant into the outdoor unit.

8. The control unit controls an outdoor unit comprising: a compressor for compressing a refrigerant; a refrigerant circuit through which the refrigerant discharged from the compressor circulates; an outdoor heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and outside air; a heat transfer medium heat exchanger provided in the refrigerant circuit for exchanging heat between the refrigerant and a liquid heat transfer medium; and a heat transfer medium circuit for sending the heat transfer medium, which has been heat-exchanged in the heat transfer medium heat exchanger, to a heat utilization destination; and the control unit determines whether or not there is a leak of refrigerant into the outdoor unit based on the outside temperature of the outdoor unit and the refrigerant pressure of the heat transfer medium heat exchanger, after the power to the outdoor unit is turned ON and before the fan starts rotating, according to claim 4.

9. An outdoor unit comprising a fan, a refrigerant detection sensor for detecting refrigerant leakage into the interior, and an outdoor unit control device according to any one of claims 1 to 8.

10. A heat pump system comprising: an outdoor unit; a fan provided on the outdoor unit; a refrigerant detection sensor provided on the outdoor unit for detecting refrigerant leakage into the outdoor unit; a control device for the outdoor unit provided on the outdoor unit as described in any one of claims 1 to 8; and a heat utilization unit connected to the outdoor unit.

11. A control method for an outdoor unit comprising a fan and a refrigerant detection sensor for detecting refrigerant leakage into the unit, comprising: a control step for controlling the rotation of the fan and a storage step for storing information that the refrigerant leakage from the refrigerant detection sensor has been detected, wherein in the control step, when the power of the outdoor unit is turned ON, if the storage step has stored information that the refrigerant leakage from the refrigerant detection sensor has been detected, the control method for an outdoor unit starts the rotation of the fan.

12. A control method for an outdoor unit comprising a fan and a refrigerant detection sensor for detecting refrigerant leakage into the unit, the method comprising a control step for controlling the rotation of the fan, wherein in the control step, the method starts the rotation of the fan when the power to the outdoor unit is turned ON.

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