Indoor unit for heat pump device

Abstract

Provided is an indoor unit for a heat pump device capable of suppressing an outflow of refrigerant leaked from a U-shaped part of a heat transfer pipe of a heat exchanger to an indoor space, and detecting a refrigerant leakage occurring in any location of the heat exchanger. To this end, the indoor unit is provided with: a first partition member partitioning the space inside a housing into a first space in which a straight part of the heat transfer pipe of the heat exchanger is disposed, and a second space in which a first U-shaped part of the heat transfer pipe of the heat exchanger is disposed, the first partition member having a first through hole formed therein for communicating the first space with the second space; a second partition member partitioning the space inside the housing into the first space and a third space in which a second U-shaped part of the heat transfer pipe of the heat exchanger is disposed, the second partition member having a second through hole formed therein for communicating the first space with the third space; a first refrigerant sensor disposed in the second space; and a second refrigerant sensor disposed in the third space. One end side of a drain pan penetrates inside the first through hole, and the other end side thereof penetrates inside the second through hole. The drain pan is disposed extending across the first space, the second space, and the third space.

Description

Indoor unit of heat pump device

[0001] The present disclosure relates to an indoor unit of a heat pump device.

[0002] In the indoor unit of an air conditioner, the indoor air intake is located at a position lower than the height of the drain pan, a partition plate is provided to separate the space below the height of the drain pan within the housing, a piping connection part connected to the refrigerant piping of the outdoor unit is located on one side of the separated space, and a heat exchanger and fan are located on the other side of the separated space, and at least one communication passage is formed in the partition plate to connect these two spaces together (see, for example, Patent Document 1).

[0003] International Publication No. 2016 / 151642

[0004] However, in an indoor unit such as that disclosed in Patent Document 1, if refrigerant leaks from the heat exchanger, there is a risk that the leaked refrigerant will flow out into the indoor space from an opening in the housing, such as an intake port.

[0005] The present disclosure has been made to solve these problems, and its purpose is to provide an indoor unit of a heat pump system that can simultaneously prevent refrigerant leaking from the U-shaped portion of the heat transfer tube of the heat exchanger from leaking into the indoor space and detect refrigerant leakage occurring at any point in the heat exchanger.

[0006] The indoor unit of a heat pump apparatus according to the present disclosure includes a heat exchanger having heat transfer tubes through which a refrigerant flows, a drain pan arranged below the heat exchanger, a refrigerant sensor that detects the refrigerant, and a housing that houses the heat exchanger, the drain pan, and the refrigerant sensor therein, wherein the heat transfer tubes have a plurality of straight portions, a first U-shaped portion that connects one end sides of the straight portions to each other, and a second U-shaped portion that connects the other end sides of the straight portions to each other, and partitions a space within the housing into a first space in which the straight portions are arranged and a second space in which the first U-shaped portions are arranged, and and a second partition member that divides the space within the housing into the first space and a third space in which the second U-shaped portion is disposed and that has a second through hole that communicates the first space with the third space, wherein the refrigerant sensors include a first refrigerant sensor disposed in the second space and a second refrigerant sensor disposed in the third space, and the drain pan is disposed across the first space, second space, and third space, with one end passing through the first through hole and the other end passing through the second through hole.

[0007] The indoor unit of the heat pump device according to the present disclosure has the advantage of being able to suppress the outflow of refrigerant leaking from the U-shaped portion of the heat transfer tube of the heat exchanger into the indoor space, and being able to detect refrigerant leakage occurring at any point in the heat exchanger.

[0008] Fig. 1 is a diagram showing an outline of the configuration of a refrigerant circuit provided in an air conditioner which is a heat pump device according to embodiment 1. Fig. 2 is a diagram showing a schematic configuration of an indoor unit of the air conditioner according to embodiment 1. Fig. 3 is a side cross-sectional view of the indoor unit according to embodiment 1. Fig. 4 is a block diagram showing the configuration of a control system of the heat pump device according to embodiment 1. Fig. 5 is a diagram explaining the configuration of a panel of the indoor unit according to embodiment 1. Fig. 6 is a diagram showing an example of the configuration for realizing the functions of a control device of the heat pump device according to embodiment 1.

[0009] An embodiment of an indoor unit of a heat pump apparatus according to the present disclosure will be described with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant explanations will be appropriately simplified or omitted. For convenience, the following description may express the positional relationship of each structure based on the illustrated state. Note that the present disclosure is not limited to the following embodiments, and any combination of the embodiments, any modification of any component of each embodiment, or any omission of any component of each embodiment are possible within the scope of the present disclosure.

[0010] Embodiment 1. A first embodiment of the present disclosure will be described with reference to Figures 1 to 6. Figure 1 is a diagram showing the schematic configuration of a refrigerant circuit provided in an air conditioner, which is a heat pump device. Figure 2 is a diagram showing a schematic configuration of an indoor unit of the air conditioner. Figure 3 is a side cross-sectional view of the indoor unit. Figure 4 is a block diagram showing the configuration of a control system for the heat pump device. Figure 5 is a diagram explaining the configuration of a panel of the indoor unit. Figure 6 is a diagram showing an example of a configuration that realizes the functions of a control device for the heat pump device.

[0011] The indoor unit of the heat pump device according to the present disclosure can be applied to, for example, air conditioners including room air conditioners and commercial packaged air conditioners, etc. As an example of the indoor unit of the heat pump device according to the present disclosure, the configuration of an air conditioner is shown in FIG.

[0012] As shown in Figure 1, the air conditioner, which is the indoor unit of the heat pump device according to this embodiment, comprises an indoor unit 1 and an outdoor unit 2. The indoor unit 1 is installed inside a room to be air-conditioned, i.e., inside the room. The outdoor unit 2 is installed outside the room, i.e., outdoors. The indoor unit 1 comprises an indoor heat exchanger 300 and an indoor fan 5. The outdoor unit 2 comprises an outdoor heat exchanger 4, an outdoor fan 6, a compressor 7, an expansion valve 8, and a four-way valve 9.

[0013] The indoor unit 1 and the outdoor unit 2 are connected by a refrigerant pipe 3. The refrigerant pipe 3 is provided in a circulating manner between the indoor heat exchanger 300 of the indoor unit 1 and the outdoor heat exchanger 4 of the outdoor unit 2. A refrigerant is sealed in the refrigerant pipe 3. From the perspective of protecting the global environment, it is desirable to use a refrigerant with a low global warming potential (GWP) as the refrigerant sealed in the refrigerant pipe 3. This refrigerant has a larger average molecular weight than air (it has a higher density than air), and has the property of sinking downward in the direction of gravity (vertical direction) in the air.

[0014] Specific examples of such refrigerants that can be used include (mixed) refrigerants made of one or more refrigerants selected from tetrafluoropropene (CFCF=CH:HFO-1234yf), difluoromethane (CHF:R32), propane (R290), propylene (R1270), ethane (R170), butane (R600), isobutane (R600a), and 1.3.3.3-tetrafluoro-1-propene (CF-CH=CHF:HFO-1234ze). Specific examples of refrigerant mixtures include R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, R459A, R474A, R479A, etc. These refrigerants include those that are flammable (slightly flammable or highly flammable).

[0015] The refrigerant pipe 3 connects the indoor heat exchanger 300, the four-way valve 9, the compressor 7, the outdoor heat exchanger 4, and the expansion valve 8 in a ring shape, thereby forming a refrigerant circuit in which the refrigerant circulates between the indoor heat exchanger 300 and the outdoor heat exchanger 4.

[0016] The compressor 7 is a device that compresses the supplied refrigerant to increase the pressure and temperature of the refrigerant. The compressor 7 may be, for example, a rotary compressor or a scroll compressor.

[0017] The expansion valve 8 expands the refrigerant that has flowed in, thereby reducing the pressure of the refrigerant. That is, the expansion valve 8 is a pressure reducing device that reduces the pressure of the refrigerant. In the configuration example described here, the expansion valve 8 is a linear electric expansion valve (LEV). Therefore, by closing the expansion valve 8, the flow of the refrigerant can be prevented.

[0018] The outdoor heat exchanger 4 exchanges heat between the refrigerant that has flowed into the outdoor heat exchanger 4 and the air. The outdoor fan 6 generates an airflow in an air passage in the outdoor unit housing, which will be described later, and blows the outside air so that it passes around the outdoor heat exchanger 4. In the outdoor heat exchanger 4, the refrigerant that has flowed in evaporates or condenses, and heat is exchanged between the refrigerant and the outdoor air sent by the outdoor fan 6, thereby cooling or heating the air.

[0019] The indoor heat exchanger 300 exchanges heat between the refrigerant that has flowed into the indoor heat exchanger 300 and the air surrounding the indoor heat exchanger 300. The indoor fan 5 blows indoor air so that it passes around the indoor heat exchanger 300, and sends the air that has been heated or cooled by the heat exchange between the refrigerant and the air in the indoor heat exchanger 300 back into the room.

[0020] The refrigerant circuit configured in this manner functions as a heat pump that transfers heat between the indoor unit 1 and the outdoor unit 2 by exchanging heat between the refrigerant and air in the indoor heat exchanger 300 and the outdoor heat exchanger 4. In this case, by switching the four-way valve 9, the direction of circulation of the refrigerant in the refrigerant circuit can be reversed, allowing the air conditioner to switch between cooling operation and heating operation.

[0021] The outdoor unit 2 includes an outdoor unit housing (not shown). The outdoor unit housing houses a compressor 7, an outdoor heat exchanger 4, an outdoor fan 6, an expansion valve 8, and part of the refrigerant piping 3. The outdoor unit housing has an intake port and an outlet port that communicate between the inside and outside of the outdoor unit housing. An air path is formed inside the outdoor unit housing, leading from the intake port, through the outdoor heat exchanger 4 and the outdoor fan 6, to the outlet port. This air path is for discharging air taken in from outside the outdoor unit housing to the outside of the outdoor unit housing after heat exchange in the outdoor heat exchanger 4.

[0022] As shown in FIGS. 2 and 3 , the indoor unit 1 includes a housing 200. The housing 200 is installed indoors. An indoor heat exchanger 300 and an indoor fan 5 are housed inside the housing 200. An air inlet 201 and an air outlet 202 are formed in the housing 200. The air inlet 201 and the air outlet 202 are openings that connect the inside and outside of the housing 200. An air passage is formed inside the housing 200, leading from the air inlet 201 to the air outlet 202. A portion of the indoor heat exchanger 300 and the indoor fan 5 are disposed in the air passage of the housing 200. The air passage of the housing 200 is for passing air through the indoor heat exchanger 300. The air that has passed through the indoor heat exchanger 300 is blown into the room from the air outlet 202 of the housing 200. As described above, the refrigerant piping 3 is connected to the indoor heat exchanger 300. Therefore, a portion of the refrigerant piping 3 is housed inside the housing 200.

[0023] The indoor heat exchanger 300 includes heat transfer tubes and fins. The heat transfer tubes are connected to the refrigerant pipes 3 at pipe connections 30, for example, by welding. A refrigerant flows through the refrigerant pipes 3 inside the heat transfer tubes. That is, a refrigerant flows inside the indoor heat exchanger 300. The heat transfer tubes are folded back on both sides of the indoor heat exchanger 300. The heat transfer tubes include straight portions 310 and U-shaped portions. A plurality of straight portions 310 are provided. Each straight portion 310 has a linear shape. The plurality of straight portions 310 are arranged parallel to each other and aligned vertically. Each straight portion 310 is arranged so that its longitudinal direction is horizontal.

[0024] The indoor heat exchanger 300 has a plurality of fins. Each fin is a flat metal plate. The fins are arranged parallel to one another at intervals. Each fin is arranged with its longitudinal direction vertical. The straight portion 310 of the heat transfer tube is provided to pass through the fins.

[0025] The U-shaped portions correspond to the portions of the heat transfer tubes that are folded back on both sides of the indoor heat exchanger 300 described above. The U-shaped portions are bent in a U shape. The U-shaped portions connect the ends of adjacent straight portions 310. A U-shaped portion is provided on each end of the straight portion 310. That is, the heat transfer tube has a first U-shaped portion 321 and a second U-shaped portion 322 as U-shaped portions. The first U-shaped portion 321 connects the straight portions 310 to each other at one end in the longitudinal direction of the straight portions 310. The second U-shaped portion 322 connects the straight portions 310 to each other at the other end in the longitudinal direction of the straight portions 310.

[0026] The connection portion between one of the first U-shaped portion 321 and the second U-shaped portion 322 and the straight portion 310 is joined by brazing, for example. The other of the first U-shaped portion 321 and the second U-shaped portion 322 is formed as a contiguous portion with two adjacent straight portions 310, for example, by bending a single pipe into a U shape. Note that both the first U-shaped portion 321 and the second U-shaped portion 322 may be joined to the straight portion 310 by brazing.

[0027] As shown in Figures 2 and 3, a drain pan 10 is provided inside the housing 200 of the indoor unit 1. The drain pan 10 is for receiving condensation water generated in the indoor heat exchanger 300. The drain pan 10 is disposed below the indoor heat exchanger 300 inside the housing 200. The drain pan 10 is inclined, for example, so that it becomes lower from one side to the other. A drain pipe (not shown) is connected to the lowest point of the inclined drain pan 10. Drain water that falls from the indoor heat exchanger 300 into the drain pan 10 is collected at the lowest point of the drain pan 10 and is discharged from the drain pipe to the outside of the housing 200 of the indoor unit 1.

[0028] As shown in FIG. 2 , the indoor unit of the heat pump apparatus according to this embodiment further includes a refrigerant sensor 20. The refrigerant sensor 20 detects the refrigerant inside the housing 200. The refrigerant sensor 20 is installed inside the housing 200. The refrigerant sensor 20 can detect at least the same type of refrigerant as that sealed in the refrigerant pipe 3. In other words, the refrigerant sensor 20 can detect the refrigerant flowing through the heat transfer tube of the indoor heat exchanger 300. The refrigerant sensor 20 can be a catalytic combustion type, semiconductor type, heat conduction type, low-potential electrolysis type, or infrared type sensor, for example. The refrigerant sensor 20 converts the refrigerant concentration around the sensor into an electrical signal and outputs the signal.

[0029] An oxygen sensor can also be used as the refrigerant sensor 20. When an oxygen sensor is used, the oxygen concentration is calculated based on the sensor output, and the decrease in oxygen concentration is assumed to be due to the inflow gas, and the concentration of the inflow gas can be calculated back to indirectly detect the concentration of the inflow gas. Oxygen sensors that can be used include, for example, galvanic cell, polaro, and zirconia types.

[0030] The indoor unit of the heat pump device is equipped with a control device 100. The control device 100 is housed inside the housing 200 of the indoor unit 1, for example, as shown in FIG. 2. The control device 100 controls the operation of the indoor unit 1. The control device 100 may control the operation of not only the indoor unit 1 but also the entire indoor unit of the heat pump device. The configuration of the control system of the indoor unit of the heat pump device according to this embodiment is shown in FIG. 4. As shown in the figure, the control device 100 is equipped with a leak detection unit 111, a memory unit 112, a notification unit 113, and a control unit 114.

[0031] Leak detection unit 111 detects the occurrence of a refrigerant leak inside housing 200 based on the detection result of refrigerant sensor 20. As described above, refrigerant sensor 20 can detect refrigerant directly or indirectly. Refrigerant sensor 20 then outputs a detection signal corresponding to the detected refrigerant concentration.

[0032] The detection signal output from refrigerant sensor 20 is input to leak detection unit 111. Leak detection unit 111 determines whether the refrigerant concentration indicated by the detection signal from refrigerant sensor 20 is equal to or greater than a refrigerant leak determination reference value. The refrigerant leak determination reference value is a preset value. The preset refrigerant leak determination reference value is stored in memory unit 112. Leak detection unit 111 makes a determination by comparing the refrigerant leak determination reference value acquired from memory unit 112 with the refrigerant concentration indicated by the detection signal from refrigerant sensor 20.

[0033] If the refrigerant concentration indicated by the detection signal from refrigerant sensor 20 is equal to or greater than the refrigerant leakage judgment reference value, leak detection unit 111 outputs a refrigerant leakage detection signal to control unit 114. The refrigerant leakage detection signal is a signal indicating that a refrigerant leakage has been detected inside housing 200. If the indoor unit of the heat pump device is equipped with refrigerant sensor 20, leak detection unit 111 detects a refrigerant leakage inside housing 200 in this manner.

[0034] The control unit 114 controls the overall operation of the indoor unit of the heat pump device by controlling the actuators provided in the indoor unit of the heat pump device. The control targets of the control unit 114 include the compressor 7, the outdoor fan 6, the expansion valve 8, the four-way valve 9, the outdoor fan 6, and the indoor fan 5.

[0035] When a refrigerant leakage detection signal is input from the leakage detection unit 111, the control unit 114 operates the indoor fan 5 if it is stopped. That is, the indoor fan 5 starts blowing air when the refrigerant sensor 20 detects a refrigerant leak. In this way, flammable leaked refrigerant that has accumulated on the indoor floor is dispersed by the airflow from the air outlet 202, and it is possible to prevent the formation of an area in the room where the concentration of leaked refrigerant exceeds the lower flammable limit concentration.

[0036] Furthermore, when a refrigerant leakage detection signal is input from the leakage detection unit 111, the control unit 114 may stop the compressor 7 if the compressor 7 is operating. In this way, it is possible to reduce the amount of refrigerant leakage thereafter. When a refrigerant leakage detection signal is input from the leakage detection unit 111 and the compressor 7 is stopped, the control unit 114 may also close the expansion valve (LEV) 8. In this way, it is possible to further reduce the amount of refrigerant leakage thereafter.

[0037] When a refrigerant leak detection signal is output from the leak detection unit 111, the notification unit 113 notifies a user or worker, etc., of the detection and urges them to carry out repairs, etc. The indoor unit of the heat pump device is equipped with a speaker for providing an audible notification or an LED for providing an optical notification that a refrigerant leak has been detected inside the housing 200. The speaker, LED, etc. are provided, for example, on the housing of the indoor unit 1 or on a remote control for the indoor unit of the heat pump device. When a refrigerant leak detection signal is output from the leak detection unit 111, the notification unit 113 uses the speaker, LED, etc. to notify that a refrigerant leak has been detected.

[0038] The internal space of the housing 200 of the indoor unit 1 according to this embodiment is divided into multiple spaces by partition members. More specifically, the housing 200 of the indoor unit 1 includes a first partition member 410 and a second partition member 420. The first partition member 410 divides the space within the housing 200 into a first space 211 and a second space 212. The straight portion 310 of the indoor heat exchanger 300 is disposed within the first space 211. The first U-shaped portion 321 of the indoor heat exchanger 300 is disposed within the second space 212. That is, the first partition member 410 is disposed at a position that separates the straight portion 310 and the first U-shaped portion 321 of the indoor heat exchanger 300. More specifically, if the straight portion 310 and the first U-shaped portion 321 are brazed to each other, the brazed portion is disposed within the second space 212. The second partition member 420 divides the space within the housing 200 into a first space 211 and a third space 213. The second U-shaped portion 322 of the indoor heat exchanger 300 is disposed within the third space 213. That is, the second partition member 420 is disposed at a position that separates the straight portion 310 of the indoor heat exchanger 300 from the second U-shaped portion 322. More specifically, when the straight portion 310 and the second U-shaped portion 322 are brazed together, the brazed portion is disposed within the third space 213. In this way, the interior of the housing 200 is divided into the first space 211, the second space 212, and the third space 213.

[0039] The aforementioned air passage that runs from the air inlet 201 to the air outlet 202 is formed in the first space 211. Therefore, the indoor fan 5 that is placed in the air passage is also placed in the first space 211. Furthermore, the aforementioned piping connection unit 30 is placed inside the second space 212 or the third space 213. In the configuration example described here, the refrigerant piping 3 is connected to the first U-shaped portion 321 side of the indoor heat exchanger 300. Therefore, the piping connection unit 30 is placed in the second space 212, which is the same as the first U-shaped portion 321.

[0040] The control device 100 is disposed inside the first space 211, the second space 212, or the third space 213. As described above, there is an air passage in the first space 211, and therefore, in order to minimize obstruction of the airflow in the air passage, it is desirable to dispose the control device 100 inside either the second space 212 or the third space 213. In the illustrated example, the control device 100 is disposed in the second space 212.

[0041] A first through hole 411 is formed in the first partition member 410. The first space 211 and the second space 212 communicate with each other via this first through hole 411. The first partition member 410 blocks air from flowing between the first space 211 and the second space 212 at locations other than the first through hole 411. The second partition member 420 also has a second through hole 421. The first space 211 and the third space 213 communicate with each other via this second through hole 421. The second partition member 420 blocks air from flowing between the first space 211 and the third space 213 at locations other than the second through hole 421.

[0042] In the indoor unit 1 according to this embodiment, one left or right end of the drain pan 10 passes through the first through-hole 411 of the first partition member 410 and protrudes into the second space 212. The other left or right end of the drain pan 10 passes through the second through-hole 421 of the second partition member 420 and protrudes into the third space 213. In this way, the drain pan 10 is disposed across the first space 211, the second space 212, and the third space 213, with one end passing through the first through-hole 411 and the other end passing through the second through-hole 421.

[0043] The indoor unit 1 according to this embodiment includes a first refrigerant sensor 21 and a second refrigerant sensor 22 as refrigerant sensors 20. The first refrigerant sensor 21 is disposed in the second space 212. The first refrigerant sensor 21 is preferably disposed below the first through-hole 411 of the first partition member 410. That is, the first refrigerant sensor 21 is preferably disposed below the portion of the drain pan 10 that passes through the first through-hole 411 and protrudes into the second space 212. The second refrigerant sensor 22 is disposed in the third space 213. The second refrigerant sensor 22 is preferably disposed below the second through-hole 421 of the second partition member 420. That is, the second refrigerant sensor 22 is preferably disposed below the portion of the drain pan 10 that passes through the second through-hole 421 and protrudes into the third space 213.

[0044] In the indoor unit 1 of the heat pump apparatus configured as described above, if refrigerant leaks from the first U-shaped portion 321 of the indoor heat exchanger 300 or from the brazed portion between the first U-shaped portion 321 and the straight portion 310, the leaked refrigerant flows downward within the second space 212. The refrigerant that has flowed downward within the second space 212 is detected by the first refrigerant sensor 21. At this time, the first partition member 410 prevents the leaked refrigerant from entering the first space 211 from the second space 212.

[0045] Furthermore, if refrigerant leaks from the second U-shaped portion 322 of the indoor heat exchanger 300 or from the brazed portion between the second U-shaped portion 322 and the straight portion 310, the leaking refrigerant flows downward within the third space 213. The refrigerant that flows downward within the third space 213 is detected by the second refrigerant sensor 22. At this time, the second partition member 420 prevents the leaking refrigerant from entering the first space 211 from the third space 213.

[0046] If refrigerant leaks from the straight portion 310 of the indoor heat exchanger 300, the leaked refrigerant descends within the first space 211. The refrigerant descending within the first space 211 is received by the drain pan 10 below the indoor heat exchanger 300 and flows over the drain pan 10. Because the drain pan 10 is inclined and refrigerant is heavier than air, the refrigerant generally flows downward along the inclination of the drain pan 10. However, depending on the force of the refrigerant leakage, the refrigerant may flow back up the inclination of the drain pan 10. As described above, one end of the drain pan 10 penetrates the first through-hole 411 and the other end penetrates the second through-hole 421. Therefore, the refrigerant above the drain pan 10 flows into the second space 212 through the first through-hole 411 or into the third space 213 through the second through-hole 421. The refrigerant that flows into second space 212 from first through-hole 411 flows downward within second space 212 and is detected by first refrigerant sensor 21. In addition, the refrigerant that flows into third space 213 from second through-hole 421 flows downward within third space 213 and is detected by second refrigerant sensor 22.

[0047] As described above, with the indoor unit 1 of the heat pump apparatus according to this embodiment, even if a refrigerant leak occurs in any of the heat transfer tubes (first U-shaped portion 321, second U-shaped portion 322, straight portion 310) of the indoor heat exchanger 300, the leaked refrigerant is guided to refrigerant sensor 20, i.e., at least one of the first refrigerant sensor 21 and the second refrigerant sensor 22, and the leaked refrigerant can be detected by refrigerant sensor 20. In this case, the leak detection unit 111 detects the occurrence of a refrigerant leak inside the housing 200 when at least one of the refrigerant concentration indicated by the detection signal from the first refrigerant sensor 21 and the refrigerant concentration indicated by the detection signal from the first refrigerant sensor 22 is equal to or greater than the refrigerant leak determination reference value.

[0048] Furthermore, even if refrigerant leaks from the first U-shaped portion 321, the second U-shaped portion 322, or the brazed portion of the heat transfer tube, which are particularly susceptible to refrigerant leakage, the leaked refrigerant can be prevented from flowing into the first space 211 where the air passage is located, and the refrigerant can be prevented from flowing into the indoor space from one or both of the inlet 201 and the outlet 202 of the housing 200. That is, while preventing refrigerant leaking into the indoor space, particularly from the U-shaped portion of the heat transfer tube of the indoor heat exchanger 300, the refrigerant sensor 20 can detect the leaked refrigerant even if a refrigerant leak occurs in any of the heat transfer tubes of the indoor heat exchanger 300. Furthermore, the first partition member 410 and the second partition member 420 can reduce the impact of airflow in the air passage within the housing 200 on the second space 212 and the third space 213. Therefore, refrigerant leaking from the first U-shaped portion 321, the second U-shaped portion 322, or the brazed portion of the heat transfer tube can reach the first refrigerant sensor 21 or the second refrigerant sensor 22 without being affected by the air flow in the air duct, making it possible to quickly detect the refrigerant leak.

[0049] In the indoor unit 1 of the heat pump apparatus according to this embodiment, the leakage detection unit 111 may stop detecting the occurrence of refrigerant leakage within the housing 200 based on the detection results of the refrigerant sensor 20 when the airflow rate of the indoor fan 5 is equal to or greater than a predetermined reference airflow rate. The reference airflow rate may be set, for example, to an airflow rate that is sufficient to diffuse refrigerant that has flowed into the room. Whether the airflow rate of the indoor fan 5 is equal to or greater than the reference airflow rate may be determined based on the rotation speed of the indoor fan 5, or may be determined by installing an airflow sensor in the air path within the housing 200.

[0050] If the airflow rate of the indoor fan 5 is equal to or greater than the reference airflow rate, even if refrigerant leaks, the airflow from the indoor fan 5 can diffuse the leaked refrigerant. Furthermore, if the airflow from the indoor fan 5 is present in the air path within the housing 200, the airflow in the air path will prevent the leaked refrigerant from traveling along the drain pan 10 to the first refrigerant sensor 21 in the second space 212 or the second refrigerant sensor 22 in the third space 213. Therefore, as described above, one approach is that the leak detection unit 111 may stop detecting the occurrence of a refrigerant leak within the housing 200 based on the detection result of the refrigerant sensor 20 when the airflow rate of the indoor fan 5 is equal to or greater than the reference airflow rate.

[0051] Alternatively, because airflow in the air duct makes it difficult for leaked refrigerant to reach the refrigerant sensor 20 via the drain pan 10 while the indoor fan 5 is operating, the refrigerant leakage judgment reference value may be set lower than when the indoor fan 5 is stopped. In this case, when the indoor fan 5 is stopped, the leak detection unit 111 detects the occurrence of a refrigerant leak in the housing 200 if the refrigerant concentration indicated by the detection signal from the refrigerant sensor 20 is equal to or greater than a predetermined first refrigerant leakage judgment reference value. When the indoor fan 5 is operating, the leak detection unit 111 detects the occurrence of a refrigerant leak in the housing 200 if the refrigerant concentration indicated by the detection signal from the refrigerant sensor 20 is equal to or greater than a predetermined second refrigerant leakage judgment reference value. Here, the second refrigerant leakage judgment reference value is less than the first refrigerant leakage judgment reference value. This is particularly effective when the indoor fan 5 is operating and the airflow rate of the indoor fan 5 is less than the aforementioned reference airflow rate. Therefore, when the indoor fan 5 is operating and the airflow rate of the indoor fan 5 is less than the aforementioned reference airflow rate, the leak detection unit 111 may be configured to detect the occurrence of a refrigerant leak within the housing 200 if the refrigerant concentration indicated by the detection signal from the refrigerant sensor 20 is equal to or greater than the aforementioned second refrigerant leak determination reference value. In this way, even when the indoor fan 5 is operating at an airflow rate that is not sufficient to sufficiently diffuse the leaked refrigerant, a refrigerant leak within the housing 200 can be quickly detected from the detection result of the refrigerant sensor 20.

[0052] The indoor unit 1 of the heat pump apparatus according to this embodiment may further include a closing means for closing one of the inlet 201 and the outlet 202, which is located relatively lower (hereinafter also referred to as the "lower opening"), when the indoor fan 5 is stopped. The closing means may be, for example, a shutter that opens and closes the lower opening. Furthermore, if the lower opening is the outlet 202 and an air deflector is provided, the lower opening may be closed by the air deflector. By providing such a closing means, if refrigerant leaks from the indoor heat exchanger 300, the piping connection unit 30, or the like when the indoor fan 5 is stopped, it is possible to prevent the refrigerant from leaking into the indoor space through the opening in the housing 200.

[0053] In the indoor unit 1 of the heat pump apparatus according to this embodiment, the leak detection unit 111 may use both the detection results of the first refrigerant sensor 21 and the detection results of the second refrigerant sensor 22 to detect the occurrence of a refrigerant leak inside the housing 200. For example, the leak detection unit 111 may detect the occurrence of a refrigerant leak inside the housing 200 when both the refrigerant concentration indicated by the detection signal from the first refrigerant sensor 21 and the refrigerant concentration indicated by the detection signal from the second refrigerant sensor 22 are equal to or greater than the above-mentioned refrigerant leak determination reference value.

[0054] The leak detection unit 111 may detect the occurrence of a refrigerant leak inside the housing 200 not only when both refrigerant concentrations indicated by the detection signals from these sensors simultaneously exceed the refrigerant leak judgment reference value, but also when one of the refrigerant concentrations indicated by the detection signals from these sensors exceeds the refrigerant leak judgment reference value within a predetermined period of time after the other refrigerant concentration exceeds the refrigerant leak judgment reference value. In this case, the refrigerant leak judgment reference value may be the same or different for the two refrigerant sensors 20. For example, the refrigerant leak judgment reference value of the refrigerant sensor 20 detected later may be lower than the refrigerant leak judgment reference value of the refrigerant sensor 20 detected earlier. That is, leak detection unit 111 may detect the occurrence of a refrigerant leak inside housing 200 when one of the refrigerant concentration indicated by the detection signal from first refrigerant sensor 21 and the refrigerant concentration indicated by the detection signal from first refrigerant sensor 21 becomes equal to or greater than a predetermined third refrigerant leak judgment reference value, and then, before a predetermined fixed time has elapsed, the other of the refrigerant concentration indicated by the detection signal from first refrigerant sensor 21 and the refrigerant concentration indicated by the detection signal from first refrigerant sensor 21 becomes equal to or greater than a predetermined fourth refrigerant leak judgment reference value. Here, the fourth refrigerant leak judgment reference value is less than the third refrigerant leak judgment reference value.

[0055] In the indoor unit 1 of the heat pump apparatus according to this embodiment, the housing 200 may include a panel 220, as shown in FIG. 5 . The panel 220 is detachably attached to, for example, one surface of the housing 200, the front surface in this example. By removing the panel 220, the front surface of the housing 200 is opened, allowing maintenance personnel to access the interior of the housing 200. In the example described here, the panel 220 is divided into three panels: a first panel 221, a second panel 222, and a third panel 223. The dividing line between the first panel 221 and the second panel 222 faces the first partition member 410 when the panel 220 is attached to the housing 200. The dividing line between the first panel 221 and the third panel 223 faces the second partition member 420 when the panel 220 is attached to the housing 200. That is, the first panel 221 corresponds to the first space 211, the second panel 222 corresponds to the second space 212, and the third panel 223 corresponds to the third space 213. In the illustrated example, the air inlet 201 and the air outlet 202 are formed in the first panel 221.

[0056] The first panel 221, the second panel 222, and the third panel 223 are each individually detachable from the housing 200. That is, by removing the first panel 221, the first space 211 of the housing 200 can be opened. Furthermore, by removing the second panel 222, the second space 212 of the housing 200 can be opened. And by removing the third panel 223, the third space 213 of the housing 200 can be opened. In this way, the first space 211, the second space 212, and the third space 213 of the housing 200 can be opened individually, and only the areas that need to be opened for maintenance or the like can be opened, while unnecessary areas can be kept closed. For example, when cleaning the fins and straight portions 310 of the indoor heat exchanger 300, by removing only the first panel 221, the fins and straight portions 310 of the indoor heat exchanger 300 can be cleaned without exposing the first refrigerant sensor 21 in the second space 212 and the second refrigerant sensor 22 in the third space 213. This prevents erroneous detection by the refrigerant sensor 20 due to cleaning spray gas.

[0057] Note that the panel 220 does not need to be divided into three parts, but may be divided into at least two parts. That is, the first panel 221 and the second panel 222 may be integral, and only the third panel 223 may be separated from the other parts of the panel 220. Alternatively, the first panel 221 and the third panel 223 may be integral, and only the second panel 222 may be separated from the other parts of the panel 220. In this manner, the panel 220 detachably provided on one side of the housing 200 is divided into two or more parts, and by removing a divided part of the panel 220, i.e., the second panel 222 or the third panel 223, from the housing 200, only one of the second space 212 or the third space 213 can be opened. Alternatively, by removing a divided part of the panel 220 from the housing 200, the first space 211 can be opened while one of the second space 212 or the third space 213 remains closed. Therefore, only the necessary portions can be opened without removing the entire panel 220, improving convenience for maintenance, etc. Furthermore, since portions not required for maintenance, etc. can be kept closed, it is possible to prevent the intrusion of foreign matter, etc.

[0058] FIG. 6 is a diagram showing an example of a configuration for realizing the functions of the control device 100 in this embodiment. The functions of the control device 100 are realized, for example, by a processing circuit. The processing circuit may include a processor 101 and a memory 102. The processing circuit may also be dedicated hardware 103. A part of the processing circuit may be formed as dedicated hardware 103, and the processing circuit may further include a processor 101 and a memory 102. In the example shown in the figure, a part of the processing circuit is formed as dedicated hardware 103. Furthermore, in the example shown in the figure, the processing circuit further includes a processor 101 and a memory 102.

[0059] The processing circuitry, part of which is at least one dedicated hardware 103, may be, for example, a single circuit, a multiple circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. If the processing circuitry comprises at least one processor 101 and at least one memory 102, the functionality of the control device 100 may be realized by software, firmware, or a combination of software and firmware.

[0060] The software and firmware are written as programs and stored in memory 102. The processor 101 realizes the functions of each unit by reading and executing the programs stored in memory 102. The processor 101 is also called a CPU (Central Processing Unit), central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. The memory 102 may be, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM, or a magnetic disk, flexible disk, optical disk, compact disk, minidisk, DVD, etc.

[0061] In this way, the processing circuit of the control device 100 can realize each function of the control device 100 by hardware, software, firmware, or a combination of these. When the processing circuit of the control device 100 includes at least the processor 101 and the memory 102, the processor 101 executes a program stored in the memory 102 in the control device 100, and the hardware and software of the control device 100 work together to realize the functions of each part of the control device 100. Note that the indoor unit of the heat pump device is not limited to a configuration in which its operation is controlled by a single control device 100. The indoor unit of the heat pump device may also be controlled by multiple devices working together.

[0062] The present disclosure can be used in an indoor unit of a heat pump device that includes a housing that houses a heat exchanger having heat transfer tubes through which a refrigerant flows.

[0063] REFERENCE SIGNS LIST 1 indoor unit 2 outdoor unit 3 refrigerant piping 4 outdoor heat exchanger 5 indoor fan 6 outdoor fan 7 compressor 8 expansion valve 9 four-way valve 10 drain pan 20 refrigerant sensor 21 first refrigerant sensor 22 second refrigerant sensor 30 piping connection section 100 control device 101 processor 102 memory 103 dedicated hardware 111 leak detection section 112 storage section 113 notification section 114 control section 200 housing 201 suction port 202 outlet 211 first space 212 second space 213 third space 220 panel 221 first panel 222 second panel 223 third panel 300 indoor heat exchanger 310 straight section 321 first U-shaped section 322 second U-shaped section 410 First partition member 411 First through-hole 420 Second partition member 421 Second through-hole

Claims

1. A device comprising: a heat exchanger having heat transfer tubes through which a refrigerant flows; a drain pan arranged below the heat exchanger; a refrigerant sensor that detects the refrigerant; and a housing that houses the heat exchanger, the drain pan, and the refrigerant sensor, wherein the heat transfer tubes have a plurality of straight portions, a first U-shaped portion connecting one end of the straight portions to each other, and a second U-shaped portion connecting the other end of the straight portions to each other, and further comprising: a first partition member that divides the space within the housing into a first space in which the straight portions are arranged and a second space in which the first U-shaped portions are arranged, and has a first through hole formed therein that connects the first space with the second space, and a second partition member that divides the space within the housing into the first space and a third space in which the second U-shaped portions are arranged, and has a second through hole formed therein that connects the first space with the third space, and the refrigerant sensor is an indoor unit of a heat pump device including a first refrigerant sensor arranged in the second space and a second refrigerant sensor arranged in the third space, wherein the drain pan has one end passing through the first through-hole and the other end passing through the second through-hole and is arranged across the first space, the second space, and the third space.

2. An indoor unit of a heat pump device as described in claim 1, wherein the housing has an air inlet and an air outlet, and an air path is formed inside the housing that runs from the air inlet to the air outlet, the air path being formed within the first space, and the indoor unit further comprises a fan that generates an airflow within the air path.

3. An indoor unit of a heat pump device as described in claim 2, further comprising a leakage detection unit that detects the occurrence of a leakage of the refrigerant within the housing based on the detection result of the refrigerant sensor, wherein the leakage detection unit stops detecting the occurrence of a leakage of the refrigerant within the housing based on the detection result of the refrigerant sensor when the air volume of the fan is equal to or greater than a predetermined reference air volume.

4. An indoor unit of a heat pump device as described in claim 2 or claim 3, further comprising a blocking means for blocking one of the intake port and the exhaust port, which is located relatively lower, when the fan is stopped.

5. An indoor unit of a heat pump device as described in claim 1 or claim 2, further comprising a leakage detection unit that detects the occurrence of a leakage of the refrigerant within the housing based on the detection results of the refrigerant sensor, wherein the leakage detection unit detects the occurrence of a leakage of the refrigerant within the housing based on both the detection results of the first refrigerant sensor and the detection results of the second refrigerant sensor.

6. An indoor unit of a heat pump device described in any one of claims 1 to 5, wherein the first refrigerant sensor is arranged below the first through hole in the second space, and the second refrigerant sensor is arranged below the second through hole in the third space.

7. An indoor unit of a heat pump device as described in any one of claims 1 to 6, wherein the housing comprises a panel provided on one side of the housing, the panel being divided into two or more parts, and by removing the divided part of the panel from the housing, it is possible to open only one of the second space or the third space.

8. An indoor unit of a heat pump device as described in any one of claims 1 to 6, wherein the housing comprises a panel provided on one side of the housing, the panel being divided into two or more parts, and by removing the divided parts of the panel from the housing, the first space can be opened while keeping either the second space or the third space closed.

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