Heat pump device

Abstract

Provided is a heat pump device that provides a heat exchanger that exchanges heat between a refrigerant and water inside a building, the heat pump device being capable of discharging refrigerant that has leaked from refrigerant piping to the outside and of suppressing the flow of refrigerant into an indoor space. A heat pump device according to the present invention comprises a first heat exchanger that exchanges heat between a refrigerant and air, a second heat exchanger that exchanges heat between the refrigerant and water, refrigerant piping that connects the first heat exchanger and the second heat exchanger and contains the refrigerant, and a container that contains the second heat exchanger. The second heat exchanger is provided inside a building. The container has a duct that allows the inside of the container to communicate with the outside of the building. The container hermetically isolates the space inside the container from an indoor space. The refrigerant piping passes through the duct.

Description

heat pump equipment

[0001] The present disclosure relates to a heat pump device.

[0002] A known heat pump device includes a refrigerant circuit that circulates a refrigerant, a heat medium circuit that circulates a heat medium, a heat exchanger that exchanges heat between the refrigerant and the heat medium, and an indoor unit that houses at least the heat exchanger, where the heat exchanger has a double-wall structure and the indoor unit has a container that houses the heat exchanger, and the container has a first opening that communicates with the outdoors without going through the indoor space (see, for example, Patent Document 1).

[0003] International Publication No. 2018 / 167861

[0004] However, in the heat pump apparatus disclosed in Patent Document 1, the heat exchanger that exchanges heat between the refrigerant and the heat medium is located indoors, and at least a portion of the refrigerant piping connected to the heat exchanger is also located indoors. In the heat pump apparatus disclosed in Patent Document 1, if the refrigerant leaks from such a refrigerant piping located indoors, the refrigerant cannot be discharged outdoors and may flow into the indoor space.

[0005] The present disclosure has been made to solve these problems, and its purpose is to provide a heat pump device that includes a refrigerant circuit through which a refrigerant circulates and a heat medium circuit through which a heat medium circulates, and that has a heat exchanger that exchanges heat between the refrigerant and the heat medium and is located indoors of a building, and that can discharge refrigerant that leaks from refrigerant piping outdoors and prevent the refrigerant from flowing into indoor spaces.

[0006] The heat pump device according to the present disclosure comprises a first heat exchanger that exchanges heat between a refrigerant and air, a second heat exchanger that exchanges heat between the refrigerant and water, a refrigerant pipe that connects the first heat exchanger and the second heat exchanger and has the refrigerant placed therein, and a container that houses the second heat exchanger, wherein the second heat exchanger is disposed indoors of a building, the container is provided with a duct that connects the interior of the container to the outside of the building, the internal space of the container is airtightly isolated from the indoor space by the container, and the refrigerant pipe is passed through the duct.

[0007] According to the heat pump device of the present disclosure, in a heat pump device that includes a refrigerant circuit through which a refrigerant circulates and a heat medium circuit through which a heat medium circulates, and in which a heat exchanger that exchanges heat between the refrigerant and the heat medium is located indoors of a building, it is possible to discharge refrigerant that leaks from the refrigerant piping outdoors, thereby preventing the refrigerant from flowing into indoor spaces.

[0008] 1 is a diagram schematically showing the overall configuration of a heat pump device according to embodiment 1. FIG. 2 is a block diagram showing the configuration of a control system of the heat pump device according to embodiment 1. FIG. 3 is a diagram schematically showing the overall configuration of a first modified example of the heat pump device according to embodiment 1. FIG. 4 is a diagram schematically showing the overall configuration of a second modified example of the heat pump device according to embodiment 1. FIG. 5 is a block diagram showing the configuration of a control system of the third modified example of the heat pump device according to embodiment 1. FIG. 6 is a perspective view of a duct of a fourth modified example of the heat pump device according to embodiment 1. FIG. 7 is a cross-sectional view of a duct of the fourth modified example of the heat pump device according to embodiment 1. FIG. 8 is an enlarged view of a main part of the fourth modified example of the heat pump device according to embodiment 1. FIG. 9 is a perspective view showing the sealed container side of the duct in the fourth modified example of the heat pump device according to embodiment 1. FIG. 10 is a perspective view showing the sealed container side of the duct in the fourth modified example of the heat pump device according to embodiment 1.

[0009] Embodiments of a heat pump device 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 descriptions 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 their modifications, and any combination of the embodiments and their modifications, any modification of any component of the embodiments and their modifications, or any omission of any component of the embodiments and their modifications may be possible within the scope of the present disclosure.

[0010] Embodiment 1. A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 12. FIG. 1 is a diagram schematically illustrating the overall configuration of a heat pump device. FIG. 2 is a block diagram illustrating the configuration of a control system for the heat pump device. FIG. 3 is a diagram schematically illustrating the overall configuration of a first modified example of a heat pump device. FIG. 4 is a diagram schematically illustrating the overall configuration of a second modified example of a heat pump device. FIG. 5 is a diagram schematically illustrating the overall configuration of a third modified example of a heat pump device. FIG. 6 is a block diagram illustrating the configuration of a control system for the third modified example of a heat pump device. FIG. 7 is a perspective view of a duct in a fourth modified example of a heat pump device. FIG. 8 is a cross-sectional view of a duct in the fourth modified example of a heat pump device. FIG. 9 is an enlarged view of a main portion of the fourth modified example of a heat pump device. FIGS. 10 and 11 are perspective views showing the sealed container side of a duct in the fourth modified example of a heat pump device. FIG. 12 is a diagram illustrating an example of a configuration for implementing the functions of a control device for a heat pump device.

[0011] The heat pump device according to this disclosure can be applied to, for example, air conditioners including room air conditioners and commercial packaged air conditioners, water heaters, showcases, refrigerators, chiller systems, etc., and can be used in heat pump devices that have a primary circuit (refrigerant circuit) through which a refrigerant circulates and a secondary circuit (heat medium circuit) through which a liquid heat medium (for example, water) circulates.

[0012] As shown in Fig. 1, the heat pump apparatus according to this embodiment includes an outdoor unit 10 and an indoor unit 20. The outdoor unit 10 is installed outdoors 2 of a building 1. The indoor unit 20 is installed indoors 3 of the building 1. The indoor unit 20 is installed in an indoor space such as a kitchen, bathroom, storage space (such as a storeroom), or laundry room within the indoors 3. The indoor unit 20 is used to exchange heat between a refrigerant and a heat medium such as water. The water heated or cooled by heat exchange with the refrigerant is distributed from the indoor unit 20 to a load at the destination.

[0013] The outdoor unit 10 includes a compressor 12, an outdoor heat exchanger 14, an outdoor fan 15, and an expansion valve 16. The indoor unit 20 includes a water heat exchanger 21, water piping 23, an air vent valve 24, a pump 25, a heater 26, and an expansion tank 27. The outdoor unit 10 and the indoor unit 20 are connected by refrigerant piping 11.

[0014] The refrigerant piping 11 is provided in a circulating manner between the outdoor heat exchanger 14 of the outdoor unit 10 and the water heat exchanger 21 of the indoor unit 20. A refrigerant is sealed in the refrigerant piping 11. From the viewpoint 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 piping 11. 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.

[0015] 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).

[0016] The refrigerant pipe 11 connects the compressor 12, the outdoor heat exchanger 14, the expansion valve 16, and the water heat exchanger 21 in a ring shape, thereby forming a refrigerant circuit in which the refrigerant circulates between the outdoor heat exchanger 14 and the water heat exchanger 21.

[0017] The compressor 12 is a device that compresses the supplied refrigerant to increase the pressure and temperature of the refrigerant. The compressor 12 may be, for example, a rotary compressor or a scroll compressor.

[0018] The expansion valve 16 expands the refrigerant that has flowed in, thereby reducing the pressure of the refrigerant. In other words, the expansion valve 16 is a pressure reducing device that reduces the pressure of the refrigerant. In the configuration example described here, the expansion valve 16 is a linear electric expansion valve (LEV). Therefore, by closing the expansion valve 16, the flow of the refrigerant can be prevented.

[0019] The outdoor heat exchanger 14 is a heat source-side air heat exchanger that exchanges heat between the air and the refrigerant that has flowed into the outdoor heat exchanger 14. The outdoor fan 15 generates an airflow in an air path in the outdoor unit housing, which will be described later, and blows the outside air so that it passes around the outdoor heat exchanger 14. The outdoor heat exchanger 14 evaporates or condenses the refrigerant that has flowed into it, thereby exchanging heat with the outdoor air 2 sent from the outdoor fan 15 and cooling or heating the air.

[0020] A water pipe 23 is connected to the indoor unit 20. The water pipe 23 is provided in a circulating manner between the water heat exchanger 21 of the indoor unit 20 and the load heat exchanger 30 on the user side. Water, which is a liquid heat medium, is sealed inside the water pipe 23. In other words, the water pipe 23 is a heat medium pipe that contains water, which is a liquid heat medium. Water is one example of a liquid heat medium. Other liquid heat mediums that can be used include brine.

[0021] The water heat exchanger 21 is a liquid heat exchanger that exchanges heat between the refrigerant that has flowed into the water heat exchanger 21 and water (liquid heat medium). The water heat exchanger 21 may be, for example, a plate heat exchanger or a double-pipe heat exchanger, which have high heat exchange efficiency.

[0022] The load heat exchanger 30 is a user-side heat exchanger that exchanges heat between water (liquid heat medium) that flows into the load heat exchanger 30 and an object to be heated or cooled using the heat. The object to be heated or cooled using the heat varies depending on whether the heat pump device is applied to an air conditioner, water heater, showcase, refrigerator, etc. For example, if the heat pump device is applied to an air conditioner, showcase, or refrigerator, the object to be heated or cooled using the heat is air. Also, if the heat pump device is applied to a water heater, the object to be heated, etc. using the heat is water. The load heat exchanger 30 heats or cools the target air, water, etc. by exchanging heat between the high-temperature or low-temperature water that flows into the load heat exchanger 30 and the target air, water, etc.

[0023] The outdoor heat exchanger 14 in this embodiment is an example of a first heat exchanger that exchanges heat between a refrigerant and air. The water heat exchanger 21 in this embodiment is an example of a second heat exchanger that exchanges heat between a refrigerant and water. The load heat exchanger 30 in this embodiment is an example of a third heat exchanger that exchanges heat between water and air. The outdoor heat exchanger 14, which is the first heat exchanger, is located outdoors 2 of the building 1. The water heat exchanger 21, which is the second heat exchanger, and the load heat exchanger 30, which is the third heat exchanger, are located indoors 3 of the building 1. The refrigerant piping 11 connects the outdoor heat exchanger 14, which is the first heat exchanger, and the water heat exchanger 21, which is the second heat exchanger, in a circular configuration.

[0024] The water piping 23 connects the water heat exchanger 21, which is the second heat exchanger, and the load heat exchanger 30, which is the third heat exchanger, in a ring shape. That is, the water piping 23 has an outflow water piping and a return water piping. The outflow water piping is a piping through which water flows from the water heat exchanger 21 to the load heat exchanger 30. The return water piping is a piping through which water flows from the load heat exchanger 30 to the water heat exchanger 21.

[0025] The pump 25 is used to cause water, which is a liquid heat medium, to flow through the water heat exchanger 21 and the load heat exchanger 30. The pump 25 is provided on the return water pipe of the water pipe 23. The water pipe 23 connects the water heat exchanger 21, the load heat exchanger 30, and the pump 25 in a circular configuration. Therefore, a water circuit is formed in which water is circulated between the water heat exchanger 21 and the load heat exchanger 30 by the pump 25.

[0026] The pump 25 causes water (liquid heat medium) to flow in a predetermined circulation direction through the annular water pipe 23 (heat medium pipe) formed in this manner. This circulation direction is the direction in which water, which is the liquid heat medium, passes through the pump 25, the water heat exchanger 21, which is a liquid heat exchanger, and the load heat exchanger 30 in this order.

[0027] A heater 26 and an expansion tank 27 are provided in the outbound water pipe of the water pipe 23. The heater 26 heats the water flowing in the outbound water pipe from the water heat exchanger 21 toward the load heat exchanger 30. For example, if the load heat exchanger 30 is not sufficiently heating the water, the heater 26 can further heat the water flowing in the outbound water pipe. The expansion tank 27 is a device for controlling pressure changes in the water circuit (water pipe 23) that occur due to temperature changes in the water pipe 23 within a certain range. The expansion tank 27 expands and contracts in response to increases and decreases in water pressure in the water pipe 23, thereby keeping the water pressure in the water pipe 23 within a certain range.

[0028] An air vent valve 24 is further provided on the outward water pipe of the water pipe 23. The air vent valve 24 is a valve that can discharge gases such as air inside the water pipe 23 to the outside. For example, a float-type automatic air vent valve is used as the air vent valve 24. A float-type automatic air vent valve has a sealing function that prevents backflow of air using a float, and can discharge only gases in the water. More specifically, under normal circumstances, the inside of the air vent valve 24 is filled with water, and the opening and the float are tightly sealed. When air accumulates inside the air vent valve 24, the float floats on the water and descends to the water surface, creating a gap between the opening and the float, allowing only the air to be discharged to the outside.

[0029] Air present in the water piping 23 of the water circuit, etc., impedes the smooth flow of water. Furthermore, if air enters the pump 25, it may run idle (so-called "air entrapment"), preventing water circulation. For example, gases such as air may enter the water circuit during installation of the heat pump device. Furthermore, gases such as air may separate from the water in the water circuit during test operation of the heat pump device. When gas enters the water circuit in this way, the gas circulates within the water circuit along with the water, which serves as the heat medium. The gas circulating within the water circuit is discharged from the air vent valve 24 to the outside of the water circuit as it passes through the air vent valve 24 installed in the outward water piping. This prevents air from entering the pump 25 and prevents the pump 25 from running idle.

[0030] The outdoor unit 10 includes an outdoor unit housing. The outdoor unit housing houses a compressor 12, an outdoor heat exchanger 14, an outdoor fan 15, an expansion valve 16, and part of the refrigerant piping 11. The indoor unit 20 includes an indoor unit housing. The indoor unit housing houses a water heat exchanger 21, an air vent valve 24, a pump 25, a heater 26, an expansion tank 27, part of the refrigerant piping 11, and part of the water piping 23.

[0031] The outdoor unit housing has an air inlet and an air outlet that connect the inside and outside of the outdoor unit housing. Inside the outdoor unit housing, an air path is formed that runs from the air inlet through the outdoor heat exchanger 14 and the outdoor fan 15 to the air outlet. This air path is for air taken in from outside the outdoor unit housing to be heat exchanged in the outdoor heat exchanger 14 and then released to the outside of the outdoor unit housing.

[0032] The refrigerant circuit and water circuit configured in this manner exchange heat between the refrigerant and air in the outdoor heat exchanger 14, between the refrigerant and water in the water heat exchanger 21, and between the water and air in the load heat exchanger 30, thereby functioning as a heat pump that transfers heat between the outdoor unit 10 on the heat source side and the load heat exchanger 30 on the user side. In other words, this is an indirect type heat pump device that uses a primary circuit (refrigerant circuit) in which a flammable refrigerant circulates and a secondary circuit in which a non-flammable heat medium (water in this case) circulates.

[0033] The outdoor unit 10 may further include a four-way valve (not shown) that switches the circulation direction of the refrigerant in the refrigerant circuit. The four-way valve switches whether the discharge side of the compressor 12 is connected to the outdoor heat exchanger 14 or the water heat exchanger 21. The four-way valve switches whether the discharge side of the compressor 12 is connected to the outdoor heat exchanger 14 or the water heat exchanger 21. By switching the four-way valve, the circulation direction of the refrigerant in the refrigerant circuit can be reversed.

[0034] By switching the four-way valve, the direction of refrigerant circulation in the refrigerant circuit can be reversed to switch between cooling operation and heating operation. In cooling operation, the four-way valve connects the discharge side of the compressor 12 to the outdoor heat exchanger 14. In the present disclosure, connecting the discharge side of the compressor 12 to the outdoor heat exchanger 14 using the four-way valve is also referred to as "setting the four-way valve for cooling." On the other hand, in heating operation, the four-way valve connects the discharge side of the compressor 12 to the water heat exchanger 21 using the four-way valve. In the present disclosure, connecting the discharge side of the compressor 12 to the water heat exchanger 21 using the four-way valve is also referred to as "setting the four-way valve for heating."

[0035] During cooling operation, the refrigerant in the primary refrigerant circuit is heated to a high temperature and high pressure by the compressor 12, passes through the four-way valve, and flows into the outdoor heat exchanger 14. At this time, the outdoor heat exchanger 14 functions as a condenser and condenses the refrigerant that has flowed in. That is, the high-temperature refrigerant that has flowed into the outdoor heat exchanger 14 exchanges heat with the low-temperature outside air, condenses, and becomes liquid refrigerant.

[0036] The liquid refrigerant expands through the expansion valve 16, becoming a two-phase refrigerant with a mixture of gas and liquid phases at low temperature and low pressure. This low-temperature two-phase refrigerant flows into the water heat exchanger 21, where it exchanges heat with the water circulating through the water circuit and evaporates to become gas refrigerant. This heat exchange cools the water in the water circuit. That is, the water heat exchanger 21 acts as a heat absorber that absorbs heat from the water in the water circuit, cooling the water. The gas refrigerant passes through the four-way valve and flows back into the compressor 12, becoming a high-temperature, high-pressure refrigerant.

[0037] In the water circuit, water is circulated by pressure generated by the pump. The water cooled in the water heat exchanger 21 and cooled to a low temperature flows through the water pipe 23 while remaining at a low temperature, and flows into the load heat exchanger 30. The water that flows into the load heat exchanger 30 is heated through heat exchange with an object (air, water, etc.) depending on the destination of use. At this time, the target air or water, etc. is cooled. The heated water proceeds to the water pipe 23, passes through the pump 25, and flows into the water heat exchanger 21 again, where it is cooled and becomes low-temperature water.

[0038] During heating operation, the refrigerant in the primary refrigerant circuit is heated to a high temperature and pressure by the compressor 12, and flows through the four-way valve into the water heat exchanger 21. The refrigerant that flows into the water heat exchanger 21 exchanges heat with water circulating in the water circuit, condensing it and turning it into liquid refrigerant. At this time, the water circulating in the water circuit is heated. That is, the water heat exchanger 21 functions as a radiator and heats the water flowing in the water circuit.

[0039] The liquid refrigerant passes through the expansion valve 16 and expands to become a low-temperature, low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the outdoor heat exchanger 14. At this time, the outdoor heat exchanger 14 functions as an evaporator and evaporates the refrigerant that has flowed in. That is, the two-phase gas-liquid refrigerant that has flowed into the outdoor heat exchanger 14 exchanges heat with outside air and evaporates to become a gas refrigerant. The gas refrigerant flows back into the compressor 12 through the four-way valve and becomes a high-temperature, high-pressure refrigerant.

[0040] In the water circuit, water is circulated by pressure generated by the pump 25. First, high-temperature water heated in the water heat exchanger 21 flows through the water piping 23 while still at a high temperature, and flows into the load heat exchanger 30. The water that flows into the load heat exchanger 30 is cooled by heat exchange with an object (air, water, etc.) depending on its destination of use. At this time, the object, such as air or water, is heated. The cooled water proceeds to the water piping 23, passes through the pump 25, and flows into the water heat exchanger 21 again, where it is heated and becomes high-temperature water.

[0041] The heat pump device according to this embodiment further includes a sealed container 40. A water heat exchanger 21, which is a second heat exchanger, is housed inside the sealed container 40. In the illustrated example, the sealed container 40 is housed inside the housing of the indoor unit 20. However, the sealed container 40 may be provided outside the housing of the indoor unit 20.

[0042] A duct 50 is provided in the sealed container 40. The duct 50 may be made of metal, for example, using a general steel plate, or may be made of resin piping such as polyvinyl chloride, a flexible pipe, or the like. One end of the duct 50 is connected to the sealed container 40 and communicates with the interior space of the sealed container 40. The other end of the duct 50 penetrates, for example, the exterior wall of the building 1 and communicates with the outdoors 2. An exhaust port is formed at the other end of the duct 50, i.e., the end of the duct 50 facing the outdoors 2. In this way, the duct 50 connects the interior of the sealed container 40 to the outdoors 2 of the building 1.

[0043] The internal space of the sealed container 40 is airtightly isolated from the space inside the room 3 by the sealed container 40. In the illustrated example, a water pipe 23 passes through the sealed container 40. The portion where the water pipe 23 passes through the sealed container 40 is airtightly sealed with a sealant such as silicone resin, a caulking material, or the like. Therefore, the inside of the sealed container 40 is in communication with the outdoor space 2 via the duct 50, but is not in communication with the indoor space 3. In this way, the water heat exchanger 21 is sealed within the sealed container 40; that is, it is not in communication with the indoor space 3, and is disposed in a space that is in communication with the outdoor space 2.

[0044] As described above, the refrigerant pipe 11 is connected to the water heat exchanger 21. The refrigerant pipe 11 passes through the inside of the duct 50. Therefore, the refrigerant pipe 11 does not communicate with the indoor space 3, and is disposed in a space communicating with the outdoor space 2, or in the outdoor space 2.

[0045] In the heat pump device configured as described above, during cooling operation, low-temperature refrigerant flows into the water heat exchanger 21. At this time, refrigerant below 0°C (the freezing point of water) may flow into the water heat exchanger 21, causing the water circulating in the water circuit to freeze, and the volume of the water to expand due to freezing may damage the water heat exchanger 21. In addition, the water heat exchanger 21 may also be damaged due to, for example, aging, external stress, etc.

[0046] As described above, the water heat exchanger 21 is disposed in a space that is airtightly isolated from the space inside the room 3. If the water heat exchanger 21 is damaged and refrigerant leaks from the water heat exchanger 21, the leaked refrigerant flows into the sealed container 40, i.e., into the space that is airtightly isolated from the space inside the room 3. Then, the leaked refrigerant in the sealed container 40 is discharged to the outside 2 through the duct 50.

[0047] As described above, the refrigerant piping 11 is also arranged in a space that is airtightly isolated from the space inside the room 3. Therefore, even if refrigerant leaks from the connection between the water heat exchanger 21 and the refrigerant piping 11 or from the refrigerant piping 11, the leaking refrigerant flows into the sealed container 40, i.e., into a space that is airtightly isolated from the space inside the room 3. The leaking refrigerant in the sealed container 40 is then discharged to the outdoor space 2 through the duct 50. In this way, in the heat pump device according to this embodiment, even if refrigerant leakage occurs in either the water heat exchanger 21 or the refrigerant piping 11 provided in the indoor unit 20 inside the room 3, the leaking refrigerant can be prevented from flowing into the space inside the room 3.

[0048] As shown in FIG. 1 , the air vent valve 24 may be further housed within the sealed container 40. In this configuration, the air vent valve 24 is disposed in a space that does not communicate with the indoor space 3 but communicates with the outdoor space 2. If the water heat exchanger 21 is damaged, the refrigerant flow path and the water flow path within the water heat exchanger 21 may become connected. In this case, if the internal pressure of the refrigerant pipe 11 is higher than the internal pressure of the water pipe 23, the refrigerant in the refrigerant pipe 11 of the refrigerant circuit may infiltrate the water pipe 23 of the water circuit. The refrigerant flowing into the water heat exchanger 21 is a high-pressure refrigerant compressed by the compressor 12. Therefore, if the water heat exchanger 21 is damaged and the refrigerant flow path and the water flow path within the water heat exchanger 21 become connected, the refrigerant will infiltrate the water pipe 23 of the water circuit, and the infiltrated refrigerant will become gas and flow through the water circuit. The gaseous refrigerant that has infiltrated into the water pipe 23 is then discharged from the water pipe 23 through the air vent valve 24.

[0049] By accommodating the air vent valve 24 inside the sealed container 40, the refrigerant discharged from the air vent valve 24 in such a case can be kept inside the sealed container 40, i.e., in a space that is airtightly isolated from the space inside the room 3. The refrigerant inside the sealed container 40 can then be discharged to the outside 2 through the duct 50. Therefore, in this case as well, the refrigerant can be prevented from leaking into the space inside the room 3.

[0050] As shown in Fig. 1 , the heat pump apparatus according to this embodiment may further include a blower fan 60. The blower fan 60 generates an airflow inside the duct 50 that flows toward the outdoors 2. The blower fan 60 is provided inside the sealed container 40, inside the duct 50, or at the end of the duct 50 on the outdoors 2 side. By providing such a blower fan 60, it is possible to promote the discharge of refrigerant that has leaked into the sealed container 40 through the duct 50 to the outdoors 2, and to quickly discharge refrigerant that has leaked into the sealed container 40 to the outdoors 2.

[0051] The blower fan 60 may blow air continuously. "Continuously" here means that the blower fan 60 always operates as long as power for operation is supplied to the blower fan 60. In other words, if the heat pump apparatus is connected to, for example, a commercial power source, the blower fan 60 operates regardless of the operating state of the heat pump apparatus itself. The blower fan 60 may also be provided with an emergency battery, an uninterruptible power supply, or the like for operating the blower fan 60. This allows the refrigerant leaking inside the sealed container 40 to be quickly discharged to the outdoor area 2 even if a refrigerant leak occurs when the heat pump apparatus is not operating. In particular, when the heat pump apparatus is applied to an air conditioner, the heat pump apparatus may not be operated for a relatively long period of time, such as in spring or autumn. By keeping the blower fan 60 constantly operating, the refrigerant can be quickly discharged to the outdoor area 2 in the event of a refrigerant leak, even when the heat pump apparatus is not operated for a long period of time.

[0052] As shown in FIG. 1 , the heat pump apparatus according to this embodiment may further include a refrigerant sensor 41. The refrigerant sensor 41 is a sensor that detects the refrigerant inside the sealed container 40. The refrigerant sensor 41 is installed inside the sealed container 40. The refrigerant sensor 41 is capable of detecting at least the same type of refrigerant as that sealed in the refrigerant pipe 11. The refrigerant sensor 41 may be a catalytic combustion type, semiconductor type, heat conduction type, low potential electrolysis type, or infrared type sensor, for example. The refrigerant sensor 41 converts the refrigerant concentration inside the sealed container 40 into an electrical signal and outputs the signal.

[0053] An oxygen sensor can also be used as the refrigerant sensor 41. 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. Examples of oxygen sensors that can be used include galvanic cell, polaro, and zirconia types.

[0054] The configuration of the control system of the heat pump apparatus according to this embodiment is shown in Fig. 2. As shown in the figure, the heat pump apparatus according to this embodiment includes a control device 100. The control device 100 includes a leak detection unit 111, a memory unit 112, a notification unit 113, and a control unit 114.

[0055] The leak detection unit 111 detects the occurrence of a refrigerant leak inside the sealed container 40 based on the detection result of the refrigerant sensor 41. As described above, the refrigerant sensor 41 can detect the refrigerant directly or indirectly. The refrigerant sensor 41 then outputs a detection signal corresponding to the concentration of the detected refrigerant.

[0056] The detection signal output from the refrigerant sensor 41 is input to the leak detection unit 111. The leak detection unit 111 determines whether the refrigerant concentration indicated by the detection signal from the refrigerant sensor 41 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 the memory unit 112. The leak detection unit 111 makes a determination by comparing the refrigerant leak determination reference value acquired from the memory unit 112 with the refrigerant concentration indicated by the detection signal from the refrigerant sensor 41.

[0057] When the refrigerant concentration indicated by the detection signal from the refrigerant sensor 41 is equal to or greater than the refrigerant leak judgment reference value, the leak detection unit 111 outputs a refrigerant leak detection signal to the control unit 114. The refrigerant leak detection signal is a signal indicating that a refrigerant leak has been detected in the sealed container 40. When the heat pump device is equipped with the refrigerant sensor 41, the leak detection unit 111 detects a refrigerant leak inside the sealed container 40 in this manner. By providing the refrigerant sensor 41 for detecting a refrigerant leak inside the sealed container 40 that houses the water heat exchanger 21, when a refrigerant leak occurs from the water heat exchanger 21 and the refrigerant pipe 11, the leaked refrigerant can be contained within the sealed container 40, preventing the leaked refrigerant from spreading, and quickly detecting the occurrence of a refrigerant leak.

[0058] The control unit 114 controls the overall operation of the heat pump device by controlling the actuators provided in the heat pump device. The control targets of the control unit 114 include the compressor 12, the outdoor fan 15, the expansion valve 16, the pump 25, and the blower fan 60. Furthermore, as described above, if the outdoor unit 10 is provided with a four-way valve, the control unit 114 controls the four-way valve.

[0059] If the heat pump device is equipped with a refrigerant sensor 41, the blower fan 60 may be operated only when a refrigerant leak is detected, rather than being operated all the time. In this case, the control unit 114 operates the blower fan 60 when a refrigerant leak detection signal is input from the leak detection unit 111. That is, the blower fan 60 blows air when the refrigerant sensor 41 detects a refrigerant leak.

[0060] When the refrigerant leakage detection signal is input from the leak detection unit 111, the control unit 114 may stop the compressor 12 if the compressor 12 is operating. In this way, the amount of refrigerant leakage thereafter can be reduced. When the refrigerant leakage detection signal is input from the leak detection unit 111 and the compressor 12 is stopped, the control unit 114 may also close the LEV 17. In this way, the amount of refrigerant leakage thereafter can be further reduced.

[0061] 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 perform repairs, etc. 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 sealed container 40. The speaker, LED, etc. are provided, for example, on the housing of the indoor unit 20, a remote control for the heat pump device, etc. 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.

[0062] As described above, the refrigerant used is heavier than air. Therefore, it is preferable to position the refrigerant sensor 41 vertically below the water heat exchanger 21 inside the sealed container 40. In this case, the refrigerant sensor 41 may or may not be directly below the water heat exchanger 21. It is even more preferable to position the refrigerant sensor 41 close to the bottom of the sealed container 40. Furthermore, it is more preferable to position the refrigerant sensor 41 vertically below not only the water heat exchanger 21, but also the refrigerant pipe 11 and the air vent valve 24.

[0063] In the heat pump device according to this embodiment, the number of ducts 50 connected to the sealed container 40 is not limited to one and may be two or more. In the configuration example shown in Fig. 1, two ducts 50, a first duct 51 and a second duct 52, are provided. That is, the duct 50 includes the first duct 51 and the second duct 52.

[0064] In this case, the refrigerant pipe 11 may be passed through either the first duct 51 or the second duct 52. Alternatively, one of the two refrigerant pipes 11 may be passed through the first duct 51 and one through the second duct 52. However, typically, the two refrigerant pipes 11 are often combined into one and covered together. In this case, the refrigerant pipes 11 are passed through either the first duct 51 or the second duct 52 together.

[0065] Furthermore, when the blower fan 60 is provided as in the configuration example of FIG. 1 , the duct 50 through which the blower fan 60 blows air may be different from the duct 50 through which the refrigerant piping 11 passes. That is, the blower fan 60 generates an airflow toward the outdoor 2 inside one of the first duct 51 and the second duct 52. The refrigerant piping 11 passes inside the other of the first duct 51 and the second duct 52. In the illustrated example, the refrigerant piping 11 passes through the first duct 51, and the blower fan 60 blows air into the second duct 52, but these may be reversed. In this way, the cross-sectional area of ​​the air passage through which the airflow generated by the blower fan 60 passes is not reduced by the refrigerant piping 11. Therefore, the blower fan 60 can quickly discharge the refrigerant in the sealed container 40 to the outdoor 2.

[0066] Furthermore, by providing two or more ducts 50, the refrigerant in the sealed container 40 can be discharged to the outdoors 2 through one duct 50 by an air flow generated by the blower fan 60, and at the same time, air from the outdoors 2 can be taken into the sealed container 40 through another duct 50. Therefore, air can be simultaneously supplied to the sealed container 40 and exhausted from the sealed container 40, causing the air from the outdoors 2 to pass through the sealed container 40, and allowing the refrigerant in the sealed container 40 to be discharged to the outdoors 2 more smoothly.

[0067] Next, several modifications of the heat pump apparatus according to this embodiment will be described. In describing these modifications, overlapping descriptions of similar features to those described above will be omitted, and differences, modifications, and variations will be mainly described. First, a first modification of the heat pump apparatus will be described with reference to FIG. 3 . In this first modification, the opening formed at the end of the duct 50 facing the outdoor area 2 is positioned vertically above the second heat exchanger. In the illustrated example, the sealed container 40 is positioned at the top of the housing of the indoor unit 20. The first duct 51 and the second duct 52 of the duct 50 each penetrate the top surface of the housing of the indoor unit 20 and are connected to the top surface of the sealed container 40. The refrigerant piping 11 passes through the duct 50 and is introduced into the housing of the indoor unit 20 from the top surface of the housing of the indoor unit 20.

[0068] According to the first modified example, refrigerant leaking from the water heat exchanger 21 or the like can be discharged to the outdoors 2 from an opening that is higher than the water heat exchanger 21. The refrigerant discharged to the outdoors 2 diffuses as it settles. Therefore, by discharging the refrigerant from a position higher than the water heat exchanger 21, it is possible to promote the diffusion of the refrigerant compared to when the refrigerant is discharged directly from the water heat exchanger 21 to the outdoors 2.

[0069] In the illustrated example, the refrigerant pipe 11 passes through the first duct 51, and the blower fan 60 blows air into the second duct 52. The opening of the second duct 52 facing the outdoor 2 is positioned vertically higher than the opening of the first duct 51 facing the outdoor 2. When the blower fan 60 is operating, an airflow from the outdoor 2 toward the inside of the sealed container 40 is generated in the first duct 51. In this situation, if refrigerant leaks from a location in the first duct 51 of the refrigerant pipe 11, the leaked refrigerant passes through the first duct 51, the sealed container 40, and the second duct 52 before being discharged to the outdoor 2. Therefore, the leaked refrigerant can be discharged to the outdoor 2 from an opening higher than the refrigerant pipe 11. This facilitates diffusion of the refrigerant compared to when the refrigerant is discharged directly from the refrigerant pipe 11 to the outdoor 2.

[0070] Next, a second modified example of the heat pump apparatus will be described with reference to FIG. 4 . In this second modified example, as shown in the figure, the sealed container 40 is disposed outside the housing of the indoor unit 20. This allows the sealed container 40 and the housing of the indoor unit 20 to be installed in different locations, thereby increasing the degree of freedom in their placement. In particular, the illustrated example is similar to the configuration of the first modified example, in that the sealed container 40 and the housing of the indoor unit 20 are separated. This allows the sealed container 40 to be positioned vertically higher than the housing of the indoor unit 20. Therefore, the position of the opening of the duct 50 on the outdoor 2 side can be easily raised, and the required length of the duct 50 can be shortened, making it easy to install the duct 50.

[0071] Next, a third modified example of the heat pump apparatus will be described with reference to FIGS. 5 and 6 . In this third modified example, the heat pump apparatus further includes a second fan 62 in addition to the first fan 61, which is the blower fan 60 described above. The second fan 62 is a fan that generates an airflow in the duct 50 from the outdoors 2 toward the inside of the sealed container 40. The first fan 61 generates an airflow from the inside of the sealed container 40 toward the outdoors 2 inside one of the first duct 51 and the second duct 52. The second fan 62 generates an airflow from the outdoors 2 toward the inside of the sealed container 40 inside the other of the first duct 51 and the second duct 52. In the illustrated example, the first fan 61 generates an airflow from the inside of the sealed container 40 toward the outdoors 2 inside the second duct 52. The second fan 62 generates an airflow from the outside 2 toward the inside of the sealed container 40 inside the first duct 51. The refrigerant piping 11 also passes through the inside of the first duct 51. In this way, by providing the first fan 61 and the second fan 62, it is possible to further promote the discharge of the refrigerant that has leaked into the sealed container 40 to the outdoors 2.

[0072] In this third modified example, the heat pump device further includes a first air flow sensor 42 and a second air flow sensor 43. The first air flow sensor 42 is a sensor that detects a first air flow, which is the air flow rate passing through the first duct 51. The second air flow sensor 43 is a sensor that detects a second air flow, which is the air flow rate passing through the second duct 52.

[0073] 6 , the detection results of the first air volume sensor 42 and the second air volume sensor 43 are input to the control device 100. The notification unit 113 calculates the difference between the first air volume detected by the first air volume sensor 42 and the second air volume detected by the second air volume sensor 43. Next, the notification unit 113 compares the difference between the first air volume and the second air volume with a preset reference value. This reference value is stored in, for example, the memory unit 112. Then, if the difference between the first air volume and the second air volume is equal to or greater than the reference value, the notification unit 113 uses one or both of the speaker and the LED described above to notify that an abnormality has occurred in the sealed container 40.

[0074] When the difference between the first air volume and the second air volume is equal to or greater than a certain value, there is a possibility that air is flowing into the sealed container 40 from a location other than the duct 50, or that air is flowing out of the sealed container 40, or both. Therefore, by providing a notification means that issues a notification when the difference between the air volume passing through the first duct 51 and the air volume passing through the second duct 52 is equal to or greater than a preset reference value, it is possible to notify the user that there is an abnormality in that the airtightness of the sealed container 40 is impaired, and to urge the user to inspect the sealed container 40, etc. Note that the first air volume sensor 42, the second air volume sensor 43, and the notification means are also applicable to a configuration in which the second fan 62 is not provided and only the first fan 61 is provided as the blower fan 60, as well as a configuration in which neither the first fan 61 nor the second fan 62 is provided, i.e., a configuration in which the blower fan 60 is provided.

[0075] Next, a fourth modified example of the heat pump apparatus will be described with reference to FIGS. 7 to 11 . In this fourth modified example, the duct 50 has a two-layer structure. That is, as shown in FIGS. 7 to 9 , the duct 50 has a first duct 51 and a second duct 52 that are coaxial with each other. The first duct 51 is disposed inside the second duct 52. In other words, the second duct 52 is disposed so as to cover the outside of the first duct 51. In this way, the duct 50 has a structure in which the first duct 51 and the second duct 52 are disposed coaxially in a two-layer cylindrical shape, and the first duct 51 and the second duct 52 are integrated into a single duct 50 on the outside. Therefore, by laying a single duct 50, both the first duct 51 and the second duct 52 can be laid, thereby improving work efficiency during laying. Furthermore, when laying the cables, both the first duct 51 and the second duct 52 can be installed by simply forming one through-hole in the exterior wall of the building 1, and there is no need to form separate holes for the first duct 51 and the second duct 52 in the exterior wall of the building 1.

[0076] In the configuration example described here, the inner first duct 51 has a larger air passage cross-sectional area than the outer second duct 51. Therefore, the refrigerant piping 11 is passed through the first duct 51. In the configuration example shown in FIGS. 7 and 8 , ribs 53 are provided in the duct 50. The ribs 53 are provided in the second duct 52. The ribs 53 are arranged across the inner and outer circumferential walls of the second duct 52. In the illustrated example, four ribs 53 are provided. Each of these ribs 53 protrudes inward from the outer circumferential wall of the second duct 52. The tip of each rib 53 contacts the inner circumferential wall of the second duct 52. By providing such ribs 53, deformation of the second duct 52 can be suppressed and a certain or greater air passage cross-sectional area can be ensured for the second duct 52.

[0077] In the configuration example shown in FIG. 9 , a blower fan 60 is provided. The blower fan 60 is a fan that generates an airflow inside the second duct 52 toward the outdoors 2. In the illustrated example, the blower fan 60 is provided inside the sealed container 40. An example of a configuration related to the blower fan 60 is shown in FIGS. 10 and 11 . In the examples shown in these figures, the blower fan 60 is housed in a fan casing 63. The blower fan 60 is, for example, a sirocco fan. A connecting member 54 is provided at the end of the second duct 52 on the sealed container 40 side. The connecting member 54 is connected to the fan casing 63. The air inlet of the fan casing 63 opens into the sealed container 40. The air outlet of the fan casing 63 is connected to the connecting member 54. In this way, the air outlet of the fan casing 63 communicates with the second duct 52 via the connecting member 54.

[0078] When the blower fan 60 operates, air and the like inside the sealed container 40 is sent into the second duct 52 via the fan casing 63 and the connecting member 54, and is then exhausted from the second duct 52 to the outdoors 2. Meanwhile, the operation of the blower fan 60 lowers the pressure inside the sealed container 40, and air from the outdoors 2 is supplied into the sealed container 40 through the first duct 51.

[0079] FIG. 12 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 by, for example, 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.

[0080] 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.

[0081] 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.

[0082] 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 heat pump device is not limited to a configuration in which its operation is controlled by a single control device 100. The operation of the heat pump device may be controlled by cooperation between multiple devices.

[0083] The present disclosure can be applied to, for example, air conditioners including room air conditioners and commercial packaged air conditioners, water heaters, showcases, refrigerators, chiller systems, etc., and can be used in heat pump devices that are equipped with a primary circuit (refrigerant circuit) through which a refrigerant circulates and a secondary circuit (heat medium circuit) through which a heat medium circulates, and in which a heat exchanger that exchanges heat between the refrigerant and the heat medium is located indoors in a building.

[0084] REFERENCE SIGNS LIST 1 Building 2 Outdoor 3 Indoor 10 Outdoor unit 11 Refrigerant piping 12 Compressor 14 Outdoor heat exchanger 15 Outdoor fan 16 Expansion valve 20 Indoor unit 21 Water heat exchanger 23 Water piping 24 Air vent valve 25 Pump 26 Heater 27 Expansion tank 30 Load heat exchanger 40 Sealed container 41 Refrigerant sensor 42 First air flow sensor 43 Second air flow sensor 50 Duct 51 First duct 52 Second duct 53 Rib 54 Connecting member 60 Blower fan 61 First fan 62 Second fan 63 Fan casing 100 Control device 101 Processor 102 Memory 103 Dedicated hardware 111 Leak detection unit 112 Storage unit 113 Notification unit 114 Control unit

Claims

1. A heat pump apparatus comprising: a first heat exchanger that exchanges heat between a refrigerant and air; a second heat exchanger that exchanges heat between the refrigerant and water; a refrigerant pipe that connects the first heat exchanger and the second heat exchanger and contains the refrigerant therein; and a container that houses the second heat exchanger therein, wherein the second heat exchanger is disposed indoors of a building, the container is provided with a duct that communicates the interior of the container with the outdoors of the building, the internal space of the container is hermetically isolated from the indoor space by the container, and the refrigerant pipe is passed through the duct.

2. The heat pump apparatus according to claim 1, wherein the container houses therein an air vent valve that is connected to the second heat exchanger and can discharge gas in a water pipe that contains the water therein to the outside.

3. The heat pump apparatus according to claim 1 or claim 2, further comprising a blower fan that generates an air flow toward the outdoors in the duct.

4. The heat pump apparatus according to claim 3, wherein the blower fan blows air constantly.

5. The heat pump apparatus according to claim 3, further comprising a refrigerant sensor that detects the refrigerant inside the container, and wherein the blower fan blows air when the refrigerant sensor detects the refrigerant.

6. The heat pump apparatus according to claim 5, wherein the refrigerant sensor is disposed vertically below the second heat exchanger inside the container.

7. The heat pump apparatus according to any one of claims 3 to 6, wherein the duct has a first duct and a second duct, the refrigerant pipe is passed through one of the first duct and the second duct, and the blower fan generates an air flow toward the outdoors in the other of the two ducts.

8. The heat pump apparatus according to any one of claims 3 to 6, further comprising a first fan as the blower fan and a second fan, wherein the duct has a first duct and a second duct, the first fan generates an air flow toward the outdoors in one of the first duct and the second duct, and the second fan generates an air flow toward the inside of the container in the other of the two ducts.

9. A first air volume sensor for detecting the air volume passing through the first duct, a second air volume sensor for detecting the air volume passing through the second duct, and notification means for notifying when the difference between the air volume passing through the first duct and the air volume passing through the second duct is equal to or greater than a preset reference value. The heat pump device according to claim 7 or claim 8, further comprising the above.

10. The duct has a first duct and a second duct, a first air volume sensor for detecting the air volume passing through the first duct, a second air volume sensor for detecting the air volume passing through the second duct, and the difference between the air volume passing through the first duct and the air volume passing through the second duct. The heat pump device according to claim 1 or claim 2, further comprising notification means for notifying when the value is equal to or greater than a preset reference value.

11. The heat pump device according to any one of claims 7 to 10, wherein the second duct is arranged to cover the outside of the first duct.

12. The heat pump device according to claim 11, wherein the refrigerant pipe is passed through the first duct.

13. The heat pump device according to claim 11 or claim 12, wherein ribs are provided in the second duct across the inner peripheral wall and the outer peripheral wall of the second duct.

14. The heat pump device according to any one of claims 1 to 13, wherein the opening formed at the outdoor end of the duct is arranged vertically above the second heat exchanger.

Images