EP4679006A1

EP4679006A1 - Heat source equipment and refrigeration cycle device

Info

Publication number: EP4679006A1
Application number: EP23927324.6A
Authority: EP
Inventors: Takashi TAMBA; Yasuhiko Oka; Yuki EDA
Original assignee: Daikin Europe NV; Daikin Industries Ltd
Current assignee: Daikin Europe NV; Daikin Industries Ltd
Priority date: 2023-03-10
Filing date: 2023-03-10
Publication date: 2026-01-14
Also published as: WO2024189700A1

Abstract

A heat source unit (2) includes a refrigerant circuit (20), a refrigerant container (44), a connecting portion (43), a connection pipe (42), and a casing (41). The refrigerant circuit (20) includes a compressor (21) and a heat exchanger (23). The refrigerant container (44) is connected to the refrigerant circuit (20). The refrigerant container (44) is filled with a flammable refrigerant. The connecting portion (43) is connected to the refrigerant container (44). The connection pipe (42) connects the connecting portion (43) to the refrigerant circuit (20). The casing (41) accommodates the compressor (21), the first heat exchanger (23), the refrigerant container (44), the connecting portion (43), and the connection pipe (42). The refrigerant container (44) is supported by a bottom plate (413) of the casing (41).

Description

TECHNICAL FIELD

The present disclosure relates to a heat source unit and a refrigeration cycle apparatus.

BACKGROUND ART

Patent Literature 1 ( JP 2000-28237 A ) discloses a refrigeration cycle apparatus in which a flammable refrigerant gas is charged into a refrigeration cycle from a suction-side pipe of a compressor by using a cassette-type special pressure container filled with a required amount of the refrigerant gas.

SUMMARY OF THE INVENTION

However, Patent Literature 1 described above does not disclose how the special pressure container for filling and recovering a refrigerant is installed.

A heat source unit of a first aspect includes a refrigerant circuit, a refrigerant container, a connecting portion, a connection pipe, and a casing. The refrigerant circuit includes a compressor and a heat exchanger. The refrigerant container is connected to the refrigerant circuit. The refrigerant container is filled with a flammable refrigerant. The connecting portion is connected to the refrigerant container. The connection pipe connects the connecting portion and the refrigerant circuit. The casing accommodates the compressor, the heat exchanger, the refrigerant container, the connecting portion, and the connection pipe. The refrigerant container is supported by a bottom plate of the casing.
In the heat source unit according to the first aspect, the refrigerant container filled with the flammable refrigerant is fixed to the bottom plate of the casing. Therefore, since the refrigerant container can be stably disposed, safety can be improved.
A heat source unit of a second aspect is the heat source unit according to the first aspect, in which the connecting portion is provided below the refrigerant container.
In the heat source unit according to the second aspect, the connecting portion, which is provided below the refrigerant container, is fixed to the bottom plate of the casing in a manner that the flammable refrigerant flows from below the refrigerant container. Therefore, the exhaust performance of refrigerating machine oil contained in the refrigerant can be improved.
A heat source unit according to a third aspect is the heat source unit according to the second aspect, and further includes a protective member. The protective member is disposed below the refrigerant container. The protective member protects the connecting portion.
In the heat source unit according to the third aspect, the protective member can further suppress damage to the connecting portion.
A heat source unit according to a fourth aspect is the heat source unit according to the third aspect, in which the connecting portion includes a connecting valve that opens and closes the connection pipe. The protective member protects the connecting valve. The protective member has an opening.
In the heat source unit according to the fourth aspect, the protective member can protect the connecting valve that opens and closes the connection pipe connected to the refrigerant circuit, and thus can further improve safety. Since work can be performed from the opening of the protective member, workability can be improved.
A heat source unit according to a fifth aspect is the heat source unit according to the fourth aspect, in which the opening is provided on a maintenance side.
In the heat source unit according to the fifth aspect, since the opening of the protective member is provided on the maintenance side, maintenance of the connecting portion can be performed easily.
A heat source unit according to a sixth aspect is the heat source unit according to any one of the third to fifth aspects, and further includes a base. The base is disposed on a bottom plate of the casing. The base is in contact with the protective member.
As in the heat source unit according to the sixth aspect, the refrigerant container may be fixed to the bottom plate of the casing via the base and the protective member.
The heat source unit according to a seventh aspect is a heat source unit according to the sixth aspect, in which the base is fixed to the protective member.
In the heat source unit according to the seventh aspect, since the base and the protective member disposed on the bottom plate of the casing are fixed, the protective member can protect the connecting portion more appropriately.
A heat source unit according to an eighth aspect is the heat source unit according to the sixth or seventh aspect, in which the base includes an elastic member. The elastic member is in contact with the bottom plate.
In the heat source unit according to the eighth aspect, even if the refrigerant container falls, the elastic member can suppress damage to the refrigerant container.
A heat source unit according to a ninth aspect is the heat source unit according to any one of the first to eighth aspects, in which the connection pipe includes a capillary.
In the heat source unit according to the ninth aspect, the capillary can reduce a load applied to the connecting portion.
A heat source unit of a tenth aspect is the heat source unit of any one of the first to ninth aspects, and further includes a cushioning material. The cushioning material is attached to the refrigerant container.
In the heat source unit according to the tenth aspect, the cushioning material can protect the refrigerant container when an impact such as a fall is applied.
A heat source unit according to an eleventh aspect is the heat source unit according to any one of the first to tenth aspects, in which the connection pipe is connected to a low-pressure side of the refrigerant circuit.
As in the heat source unit according to the eleventh aspect, the refrigerant container may be connected to the low-pressure side of the refrigerant circuit via the connection pipe and the connecting portion.
A refrigeration cycle apparatus according to a twelfth aspect includes a heat source unit and a utilization unit. The heat source unit is the heat source unit according to any one of the first to eleventh aspects. The utilization unit is connected to the heat source unit.
The refrigeration cycle apparatus according to the twelfth aspect can fill the refrigerant circuit with a flammable refrigerant from the refrigerant container that is stably disposed, and thus can improve safety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram of a refrigeration cycle apparatus including a heat source unit according to an embodiment of the present disclosure.
FIG. 2 is a schematic sectional view of the heat source unit.
FIG. 3 is a perspective view near a refrigerant container in the heat source unit.
FIG. 4 is a diagram in which a protective member and a cushioning material are omitted in FIG. 3.
FIG. 5 is a schematic diagram near the refrigerant container in the heat source unit.

DESCRIPTION OF EMBODIMENTS

(1) Refrigeration cycle apparatus

As shown in FIG. 1, a refrigeration cycle apparatus 1 according to one embodiment of the present disclosure includes a heat source unit 2 and a utilization unit 3. The heat source unit 2 and the utilization unit 3 are connected to each other.
The heat source unit 2 includes a refrigerant circuit 20 in which a flammable refrigerant circulates. The utilization unit 3 includes a water circuit 30 in which water circulates. The refrigeration cycle apparatus 1 causes the refrigerant circuit 20 to perform a vapor compression refrigeration cycle to heat or cool the water circulating in the water circuit 30, and performs a heating operation and a cooling operation of a target space by using this water.

(2) Heat source unit

In the following description, expressions indicating directions such as "upper", "lower", "front", "rear", "left", and "right" are used as appropriate, and these directions represent respective directions when the heat source unit 2 is installed outdoors and used in a normal state. In the present embodiment, an up-down direction is a vertical direction.
The heat source unit 2 is disposed in a space different from the target space to be heated or cooled. Here, the heat source unit 2 is installed outdoors (on a rooftop of a building, near an outer wall surface of a building, or the like).
The heat source unit 2 includes the refrigerant circuit 20, a fan 23a, a refrigerant container 44, a connecting portion 43, a connection pipe 42, a control unit 4, and a casing 41 shown in FIG. 2. Note that the heat source unit 2 shown in FIG. 1 further includes a part of the water circuit 30.

(2-1) Refrigerant circuit

The refrigerant circuit 20 is a circuit in which a refrigerant circulates during normal operations such as the heating operation and the cooling operation. In the refrigerant circuit 20, a flammable refrigerant (hereinafter referred to as "refrigerant") is sealed during normal operations. The flammable refrigerant is a refrigerant that has flammability. The flammable refrigerant is a refrigerant such as, for example, a hydrocarbon-based refrigerant, R1234yf, R1234ze, and R32. Here, the flammable refrigerant is a refrigerant classified as highly flammable (A3) under ISO817, and is R290 (propane) in the present embodiment. The refrigerant includes refrigerating machine oil. The refrigerating machine oil is, for example, polyalkylene glycol (PAG) or the like.
The refrigerant circuit 20 includes a compressor 21, a four-way switching valve 22, a first heat exchanger 23, a decompression valve 24, a second heat exchanger 25, a liquid gas heat exchanger 26, an accumulator 27, a gas injection valve 28, and an economizer heat exchanger 29.

(2-1-1) Compressor

The compressor 21 is a device to compress the refrigerant. The compressor 21 includes a suction port 21a, an injection port 21b, and a discharge port 21c. The refrigerant flows into the compressor 21 through the suction port 21a, is compressed to a high temperature and high pressure, and flows out of the discharge port 21c. The refrigerant can flow into the compressor 21 through the injection port 21b which is in the middle of a compression process.

(2-1-2) Four-way switching valve

The four-way switching valve 22 switches the refrigerant flow such that during the cooling operation, the second heat exchanger 25 functions as an evaporator, and the first heat exchanger 23 functions as a radiator. During the heating operation, the four-way switching valve 22 causes the second heat exchanger 25 to function as a radiator, and causes the first heat exchanger 23 to function as an evaporator.
Specifically, during the cooling operation, the four-way switching valve 22 connects the discharge port 21c of the compressor 21 to the first heat exchanger 23, and connects the suction port 21a of the compressor 21 to the second heat exchanger 25. During the heating operation, the four-way switching valve 22 connects the discharge port 21c of the compressor 21 to the second heat exchanger 25, and connects the suction port 21a of the compressor 21 to the first heat exchanger 23.

(2-1-3) First heat exchanger

The first heat exchanger 23 is an air heat exchanger. The first heat exchanger 23 exchanges heat between the refrigerant flowing inside and outside air (outdoor air) sent from the fan 23a. As the first heat exchanger 23, a heat exchanger suitable for the application, such as a cross-fin heat exchanger or a microchannel heat exchanger, is adopted.

(2-1-4) Decompression valve

The decompression valve 24 is an electric expansion valve. The liquid refrigerant flowing through the decompression valve 24 expands into a gas-liquid two-phase state to lower the pressure and temperature of the refrigerant. The decompression valve 24 controls a flow rate of the refrigerant passing through the decompression valve by adjusting a valve opening degree.

(2-1-5) Second heat exchanger

The second heat exchanger 25 is a water heat exchanger. In the present embodiment, the second heat exchanger 25 exchanges heat between the refrigerant flowing through the refrigerant circuit 20 and the water flowing through the water circuit 30. As the second heat exchanger 25, a heat exchanger suitable for the application, such as a plate heat exchanger, is adopted.

(2-1-6) Liquid gas heat exchanger

During the heating operation, the liquid gas heat exchanger 26 exchanges heat between the high-pressure refrigerant that is output from the refrigerant outlet of the second heat exchanger 25 and the low-pressure refrigerant flowing from the refrigerant outlet of the first heat exchanger 23 toward the suction port of the compressor 21.

(2-1-7) Accumulator

The accumulator 27 is connected between the four-way switching valve 22 and the suction port 21a of the compressor 21. The accumulator 27 collects the liquid refrigerant that has not been gasified in the evaporator, and prevents the liquid refrigerant from flowing into the suction port 21a of the compressor 21.

(2-1-8) Gas injection valve

The gas injection valve 28 is, for example, an on-off valve such as a solenoid valve, or a flow rate control valve such as an electric expansion valve. In the present aspect, the gas injection valve 28 is an electric expansion valve.

(2-1-9) Economizer heat exchanger

The economizer heat exchanger 29 is configured to exchange heat between the high-temperature liquid refrigerant flowing out of the second heat exchanger 25 and the refrigerant in a gas-liquid two-phase state flowing out of the gas injection valve 28 during the heating operation. As a result, during the heating operation, the liquid refrigerant from the second heat exchanger 25 is subcooled.
An electromagnetic valve 32 is connected between a refrigerant flow path 31 that connects the second heat exchanger 25 to the decompression valve 24, and the economizer heat exchanger 29. The electromagnetic valve 32 is closed during the cooling operation, and the refrigerant does not flow toward the economizer heat exchanger 29 and the liquid gas heat exchanger 26.

(2-2) Fan

The fan 23a causes outside air to flow to the first heat exchanger 23. The fan 23a is driven by a fan motor.

(2-3) Casing

The casing 41 shown in FIG. 2 accommodates the refrigerant circuit 20, the fan 23a, the refrigerant container 44, the connecting portion 43, and the connection pipe 42.
The casing 41 has a substantially rectangular parallelepiped shape. Specifically, the casing 41 includes a front panel 411, a top panel 412, a bottom plate 413, and side plates 414.
The front panel 411 is a plate-shaped member constituting a front surface of the casing 41. A blow-out port is formed on the front panel 411. The blow-out port is an opening for blowing out the outside air that has been taken in from the outside into the casing 41 to the outside of the casing 41.
The top panel 412 is a plate-shaped member constituting an upper surface of the casing 41. The bottom plate 413 is a plate-shaped member constituting a lower surface of the casing 41. The top panel 412 and the bottom plate 413 face each other.
The side plates 414 are plate-shaped members constituting side surfaces of the casing 41. The side plates include a left-side panel and a right-side panel. Lower portions of the side plates 414 are fixed to the bottom plate 413.
The casing 41 further includes a partition plate 415. The partition plate 415 is a plate-shaped member extending in the up-down direction. A lower portion of the partition plate 415 is fixed to the bottom plate 413 of the casing 41.
The partition plate 415 partitions the casing 41 into a first chamber S1 and a second chamber S2. The first chamber S1 is a blowing chamber, and the second chamber S2 is a machine chamber. Each of the first chamber S1 and the second chamber S2 is a space partitioned by the front panel 411, the top panel 412, the bottom plate 413, the side plates 414, and the partition plate 415 of the casing 41.

(2-4) Connection pipe

As shown in FIG. 1, the connection pipe 42 is connected to the refrigerant circuit 20. The connection pipe 42 is, for example, brazed to a pipe of the refrigerant circuit 20. In the present embodiment, the connection pipe 42 is connected to a low-pressure side of the refrigerant circuit 20. The low-pressure side refers to a side of the heat source unit 2 where the pressure of the refrigerant circulating in the refrigerant circuit 20 is relatively low. In FIG. 1, the connection pipe 42 is connected between the accumulator 27 and the liquid gas heat exchanger 26 in the refrigerant circuit 20. Since the connection pipe 42 is in communication with the refrigerant pipe constituting the refrigerant circuit 20, the refrigerant including the refrigerating machine oil circulating in the refrigerant circuit 20 may flow into the connection pipe 42.
The connection pipe 42 is a metallic pipe. As shown in FIGS. 3 and 4, the connection pipe 42 includes a capillary 421, a first connection pipe 422, and a second connection pipe 423. The capillary 421, the first connection pipe 422, and the second connection pipe 423 communicate with each other. The outer diameters of the first connection pipe 422 and the second connection pipe 423 are larger than the outer diameter of the capillary 421. Here, the first connection pipe 422 is connected to the refrigerant circuit 20. The second connection pipe 423 is connected to the connecting portion 43. The capillary 421 connects the first connection pipe 422 and the second connection pipe 423.

(2-5) Connecting portion

As shown in FIGS. 1, 4, and 5, the connecting portion 43 is connected to the refrigerant container 44. In the present embodiment, the connecting portion 43 connects the connection pipe 42 and the refrigerant container 44. Here, the connecting portion 43 communicates with the connection pipe 42 and the refrigerant container 44.
As shown in FIGS. 3 to 5, the connecting portion 43 includes a connecting valve 431 and a connecting pipe 432. The connecting valve 431 is a shut-off valve that opens and closes the connection pipe 42. When opened, the connecting valve 431 is communicated with the refrigerant circuit 20 via the connection pipe 42, and when closed, the connecting valve 431 is shut off from the refrigerant circuit 20. The second connection pipe 423 and the connecting pipe 432 are connected to the connecting valve 431. The connecting pipe 432 is connected to the refrigerant container 44. The connecting pipe 432 has an inner diameter approximately equal to the inner diameters of the first connection pipe 422 and the second connection pipe 423.

(2-6) Refrigerant container

The refrigerant container 44 is filled with a flammable refrigerant. In other words, the refrigerant container 44 is configured to be filled with a flammable refrigerant. The refrigerant container 44 is a container that supplies a flammable refrigerant to the refrigerant circuit 20. Thus, the flammable refrigerant filled in the refrigerant container 44 is supplied to the refrigerant circuit 20. Therefore, after the flammable refrigerant in the refrigerant container 44 is supplied to the refrigerant circuit 20, there is no flammable refrigerant filled inside the refrigerant container 44. In other words, the heat source unit 2 has a case where the refrigerant container 44 is filled with a flammable refrigerant and a case where the refrigerant container 44 is not filled with a flammable refrigerant.
As shown in FIGS. 2 and 5, the refrigerant container 44 is supported by the bottom plate 413 of the casing 41. In other words, the refrigerant container 44 is disposed such that a load is applied to the bottom plate 413. In the present embodiment, the refrigerant container 44 is fixed to the bottom plate 413 of the casing 41 via a protective member 46 and a base 47.
As shown in FIG. 1, the refrigerant container 44 is connected to the refrigerant circuit 20. In the present embodiment, the refrigerant container 44 is connected to the refrigerant circuit 20 via the connecting portion 43 and the connection pipe 42. Here, the refrigerant container 44 is connected to the connecting portion 43.
As shown in FIGS. 4 and 5, the connecting portion 43 is provided below the refrigerant container 44. In other words, a refrigerant exhaust portion of the refrigerant container 44 is located in a lower part of the refrigerant container 44. Further in other words, the refrigerant container 44 is disposed upside down (with the up-down direction reversed). Therefore, when the refrigerant filled in the refrigerant container 44 is supplied to the refrigerant circuit 20, the refrigerant filled inside flows from below the refrigerant container 44 to the refrigerant circuit 20.
The refrigerant container 44 is comprised of metal. The refrigerant container 44 has a substantially cylindrical shape. Specifically, as shown in FIG. 4, the refrigerant container 44 includes a cylindrical part 441, an upper part 442, and a lower part 443. The cylindrical part 441 extends in the up-down direction. The outer diameter of the upper part 442 is smaller than the outer diameter of the cylindrical part 441. The upper part 442 is connected to an upper end of the cylindrical part 441. The upper part 442 includes a lid located at the upper end. The outer diameter of the lower part 443 is smaller than the outer diameter of the cylindrical part 441. The lower part 443 is connected to a lower end of the cylindrical part 441.

(2-7) Cushioning material

As shown in FIGS. 3 to 5, a cushioning material 45 is attached to the refrigerant container 44. In FIGS. 3 and 4, the cushioning material 45 includes a first cushioning material 451 that covers the cylindrical part 441, and a second cushioning material 452 that covers the upper part 442. The first cushioning material 451 is formed by a sheet-like or cylindrical member wound around the cylindrical part 441. The sheet-like member may be either a single sheet or multiple sheets. The cushioning material 45 is comprised of, for example, an elastic material such as rubber.

(2-8) Protective member

As shown in FIGS. 2, 3, and 5, the protective member 46 is disposed below the refrigerant container 44. The protective member 46 is fixed to the refrigerant container 44. Here, the protective member 46 is integrated with the refrigerant container 44. In more detail, the protective member 46 is integrated with the refrigerant container 44 by welding, and is not detachable from the refrigerant container 44.
As shown in FIGS. 3 and 5, the protective member 46 protects the connecting portion 43. The protective member 46 protects at least the connecting valve 431. Here, the protective member 46 protects the connecting portion 43 from the connecting valve 431 to the refrigerant container 44.
In FIG. 3, the protective member 46 covers the connecting portion 43 while being spaced apart from the connecting portion 43. Specifically, the protective member 46 is cylindrical. The protective member 46 may surround an entire periphery of the connecting portion 43, but has an opening 461 here. The opening 461 is provided on a maintenance side. The maintenance side is, for example, the front panel 411 side, the side plate 414 side, or the like. In FIGS. 3 and 5, the opening 461 is located on the front panel 411 side. As shown in FIG. 3, the second connection pipe 423 connected to the connecting valve 431 passes through the opening 461.
The protective member 46 is comprised of, for example, metal. The protective member 46 preferably has a thickness between 2 mm and 10 mm inclusive, more preferably between 3 mm and 6 mm inclusive.

(2-9) Base

As shown in FIGS. 2 to 5, the base 47 is provided below the refrigerant container 44 and the protective member 46. The base 47 is in contact with the protective member 46. Here, the base 47 is fixed to the protective member 46. In FIG. 3, the base 47 is fixed to the protective member 46 with a bolt B.
The base 47 is disposed on the bottom plate 413 of the casing 41. Here, the base 47 is fixed to the bottom plate 413.
The base 47 includes an elastic member 471, a support base 472, and a coupling member 473. The elastic member 471 is in contact with the bottom plate 413. The elastic member 471 is comprised of, for example, rubber. The coupling member 473 is disposed on the elastic member 471. The coupling member 473 couples the elastic member 471 and the support base 472. The support base 472 is disposed on the coupling member 473. The support base 472 is fixed to the protective member 46. The support base 472 and the coupling member 473 is comprised of, for example, metal.

(2-10) Control unit

The control unit 4 shown in FIG. 1 controls components of the heat source unit 2. The control unit 4 is configured by communicatively connecting components such as the compressor 21, the four-way switching valve 22, the decompression valve 24, the gas injection valve 28, and the electromagnetic valve 32.
The control unit 4 is embodied by a computer. The control unit 4 includes a control calculator and a storage. A processor such as a CPU or a GPU can be used for the control calculator. The control calculator reads a program stored in the storage and performs predetermined image processing and calculation processing in accordance with the program. Furthermore, the control calculator can write a calculation result to the storage and read information stored in the storage in accordance with the program.

(3) Utilization unit

The utilization unit 3 is installed inside a building. The heat source unit 2 and the utilization unit 3 are thermally connected to each other via the second heat exchanger 25. Here, the water circuit 30 of the utilization unit 3 is connected to a water flow path flowing inside the second heat exchanger 25.

(4) Behavior

Description is made to behavior of the refrigeration cycle apparatus 1 with reference to FIG. 1. The refrigeration cycle apparatus 1 can perform the cooling operation to cool indoor air and the heating operation to heat indoor air for air conditioning of an indoor space. The control unit 4 controls behavior of the refrigeration cycle apparatus 1 during the heating operation and the cooling operation.
Note that dashed arrows in FIG. 1 indicate the flow of the refrigerant in the refrigerant circuit 20 during the heating operation, while solid arrows indicate the flow of the refrigerant in the refrigerant circuit 20 during the cooling operation.

(4-1) Heating operation

During the heating operation, the four-way switching valve 22 switches the flow path as shown by the dashed lines in FIG. 1, and the control unit 4 circulates the refrigerant in the order of the compressor 21, the second heat exchanger 25, the decompression valve 24, and the first heat exchanger 23.
The refrigerant compressed to high temperature and high pressure by the compressor 21 becomes a high-temperature gas refrigerant, flows out of the discharge port 21c, and flows into the second heat exchanger 25. In the second heat exchanger 25, the high-temperature gas refrigerant heats the water in the water circuit 30, and the refrigerant is liquefied. The water that has exchanged heat with the refrigerant circulates through the water circuit 30 to heat the air in the target space.
The control unit 4 monitors the temperature of the refrigerant coming out of the discharge port 21c of the compressor 21 via a temperature sensor 50. When the temperature exceeds a predetermined value, the control unit 4 opens the gas injection valve 28.
The liquid refrigerant that has flowed out of the second heat exchanger 25 flows toward the economizer heat exchanger 29 and flows into a first flow path 29a of the economizer heat exchanger 29. The refrigerant that has flowed into the first flow path 29a partially branches off to a second flow path 29b flowing toward the gas injection valve 28, while the remainder branches off to a liquid refrigerant flow path 26b of the liquid gas heat exchanger 26. The refrigerant that has flowed into the second flow path 29b passes through the gas injection valve 28, is brought into a low-temperature gas-liquid two-phase state, and then flows into the economizer heat exchanger 29.
In the economizer heat exchanger 29, the refrigerant in the gas-liquid two-phase state from the gas injection valve 28 exchanges heat with the high-temperature liquid refrigerant flowing through the first flow path 29a. As a result, the refrigerant in the gas-liquid two-phase state is heated to become a nearly saturated gas refrigerant, while the liquid refrigerant flowing through the first flow path 29a is subcooled.
The gas refrigerant that has flowed out of the economizer heat exchanger 29 flows into the injection port 21b of the compressor 21. The injection port 21b of the compressor 21 is located in the middle of a compression stage of the compressor 21. Therefore, the gas refrigerant flowing in through the injection port 21b will enter where the refrigerant from the suction port 21a has already been partially compressed.
The refrigerant flowing through the liquid refrigerant flow path 26b of the liquid gas heat exchanger 26 flows toward the decompression valve 24. The refrigerant that has flowed into the decompression valve 24 expands in the decompression valve 24 and is brought into a low-temperature gas-liquid two-phase state. The refrigerant flows into the first heat exchanger 23 and evaporates in the first heat exchanger 23.
The refrigerant that has flowed out of the first heat exchanger 23 flows through the gas refrigerant flow path 26a of the liquid gas heat exchanger 26 and flows toward the accumulator 27. The refrigerant that has flowed into the accumulator 27 has an excess liquid component collected in the accumulator 27.
In the liquid gas heat exchanger 26, heat is exchanged between the liquid refrigerant heading for the decompression valve 24 and the gas refrigerant that has flowed out of the first heat exchanger 23, and thus, the refrigerant flowing toward the decompression valve 24 is subcooled.
The gas refrigerant that has flowed out of the accumulator 27 returns to the suction port 21a of the compressor 21. Thereafter, the gas refrigerant is compressed to high temperature and high pressure by the compressor 21.

(4-2) Cooling operation

During the cooling operation, the four-way switching valve 22 switches the flow path as shown by the solid lines in FIG. 1, and the control unit 4 circulates the refrigerant in the order of the compressor 21, the first heat exchanger 23, the decompression valve 24, and the second heat exchanger 25.
The refrigerant compressed to high temperature and high pressure by the compressor 21 becomes a high-temperature gas refrigerant, flows out of the discharge port 21c, and flows into the first heat exchanger 23. In the first heat exchanger 23, the high-temperature gas refrigerant exchanges heat with outside air, and the refrigerant is liquefied.
The liquid refrigerant that has flowed out of the first heat exchanger 23 expands at the decompression valve 24 to be brought into a low-temperature gas-liquid two-phase state. The refrigerant flows into the second heat exchanger 25 via the refrigerant flow path 31. Since the electromagnetic valve 32 is closed during the cooling operation, the refrigerant flowing through the refrigerant flow path 31 does not flow into the economizer heat exchanger 29.
The refrigerant that has flowed into the second heat exchanger 25 exchanges heat with the water flowing through the water circuit 30 in the second heat exchanger 25, evaporates, and cools the water. The water that has exchanged heat with the refrigerant circulates through the water circuit 30 to cool the air in the target space.
The gas refrigerant that has flowed out of the second heat exchanger 25 flows toward the accumulator 27 via the gas refrigerant flow path 26a of the liquid gas heat exchanger 26. The refrigerant that has flowed into the accumulator 27 has an excess liquid component collected in the accumulator 27.
The gas refrigerant that has flowed out of the accumulator 27 returns to the suction port 21a of the compressor 21. Thereafter, the gas refrigerant is compressed to high temperature and high pressure by the compressor 21.

(5) Refrigerant filling method

A method for sealing a flammable refrigerant into the refrigerant circuit 20 of the heat source unit 2 will be described with reference to FIGS. 1 to 5.
First, the heat source unit 2 that includes the refrigerant circuit 20, the connection pipe 42 connected to the refrigerant circuit 20, the connecting portion 43 connected to the connection pipe 42, the refrigerant container 44 connected to the connecting portion 43, the cushioning material 45 attached to the refrigerant container 44, the protective member 46 that protects the connecting portion 43, and the base 47 that is fixed to the protective member 46 is prepared. A small amount of flammable refrigerant is sealed in the refrigerant circuit 20. The refrigerant container 44 is filled with a flammable refrigerant. Such a heat source unit 2 is transported to an installation location (site).
At the site, the heat source unit 2 is installed. Then, by opening the connecting valve 431, the refrigerant filled in the refrigerant container 44 is allowed to flow into the refrigerant circuit 20 through the connecting portion 43 and the connection pipe 42. This allows the flammable refrigerant filled in the refrigerant container 44 to be supplied to the refrigerant circuit 20. In this way, in the present embodiment, the flammable refrigerant is sealed in the refrigerant circuit 20 during the installation of the heat source unit 2.

(6) Characteristics

(6-1)
The heat source unit 2 according to the present embodiment includes the refrigerant circuit 20, the refrigerant container 44, the connecting portion 43, the connection pipe 42, and the casing 41. The refrigerant circuit 20 includes the compressor 21 and the first heat exchanger 23. The refrigerant container 44 is connected to the refrigerant circuit 20. The refrigerant container 44 is filled with a flammable refrigerant. The connecting portion 43 is connected to the refrigerant container 44. The connection pipe 42 connects the connecting portion 43 and the refrigerant circuit 20. The casing 41 accommodates the compressor 21, the first heat exchanger 23, the refrigerant container 44, the connecting portion 43, and the connection pipe 42. The refrigerant container 44 is supported by the bottom plate 413 of the casing 41.
In the heat source unit 2 according to the present embodiment, the refrigerant container 44 filled with the flammable refrigerant is fixed to the bottom plate 413 of the casing 41. Therefore, the refrigerant container 44 can be more stably disposed than in a case where the refrigerant container is fixed to a support in a cantilever manner. Therefore, even when the refrigerant container 44 is filled with the flammable refrigerant, safety can be improved.
(6-2)
In the heat source unit 2 according to the present embodiment, the connecting portion 43 is preferably provided below the refrigerant container 44.
Here, the connecting portion 43, which is provided below the refrigerant container 44, is fixed to the bottom plate 413 of the casing 41 in a manner that the flammable refrigerant flows from below the refrigerant container 44 to the refrigerant circuit 20. Therefore, after the refrigerant is supplied from the refrigerant container 44 to the refrigerant circuit 20, during normal operations such as the cooling operation and the heating operation, even if the refrigerating machine oil flows into the refrigerant container 44, the refrigerating machine oil can be easily exhausted because the refrigerant container 44 is disposed upside down. Therefore, the exhaust performance of the refrigerating machine oil contained in the refrigerant can be improved.
Since the refrigerant container 44 is disposed upside down, the length of the connection pipe 42 can be shortened.
(6-3)
The heat source unit 2 according to the present embodiment preferably further includes the protective member 46. The protective member 46 is disposed below the refrigerant container 44. The protective member 46 protects the connecting portion 43.
Here, the protective member 46 protects the connecting portion 43 that is connected to the refrigerant container 44 filled with a flammable refrigerant. This makes it possible to suppress damage to the connecting portion 43, for example, during the installation of the heat source unit 2.
(6-4)
In the heat source unit 2 according to the present embodiment, the connecting portion 43 preferably includes the connecting valve 431 that opens and closes the connection pipe 42. The protective member 46 protects the connecting valve 431. The protective member 46 has the opening 461.
Here, the protective member 46 can protect the connecting valve 431 that opens and closes the connection pipe 42 connected to the refrigerant circuit 20, and thus can further improve safety. Since work can be performed from the opening 461 of the protective member 46, workability can be improved.
(6-5)
In the heat source unit 2 according to the present embodiment, the opening 461 is preferably provided on the maintenance side.
Here, since the opening 461 of the protective member 46 is provided on the maintenance side, when a worker removes a plate on the maintenance side in the casing 41 (for example, the front panel 411), maintenance of the connecting portion 43, such as the connecting valve 431, can be easily performed from the opening 461.
(6-6)
The heat source unit 2 according to the present embodiment preferably further includes the base 47. The base 47 is disposed on the bottom plate 413 of the casing 41. The base 47 is in contact with the protective member 46.
In this way, the refrigerant container 44 may be fixed to the bottom plate 413 of the casing 41 via the base 47 and the protective member 46.
(6-7)
In the heat source unit 2 according to the present embodiment, the base 47 is preferably fixed to the protective member 46.
Here, since the base 47 disposed on the bottom plate 413 of the casing 41 and the protective member 46 are fixed to each other, the protective member 46 can protect the connecting portion 43 more appropriately.
(6-8)
In the heat source unit 2 according to the present embodiment, the base 47 preferably includes the elastic member 471. The elastic member 471 is in contact with the bottom plate 413.
Here, even if the refrigerant container 44 falls, the elastic member 471 mitigates the impact caused by the fall, and can suppress damage to the refrigerant container 44.
(6-9)
In the heat source unit 2 according to the present embodiment, the connection pipe 42 preferably includes the capillary 421.
Here, even if a load is applied to the connection pipe 42 from the refrigerant circuit 20, the capillary 421 serves the role of an elastic member, and can reduce the load applied to the connecting portion 43 (particularly, the connecting valve 431).
(6-10)
The heat source unit 2 according to the present embodiment preferably further includes the cushioning material 45. The cushioning material 45 is attached to the refrigerant container 44.
Here, even if an impact such as a fall is applied to the refrigerant container 44, the cushioning material 45 mitigates the impact and can protect the refrigerant container 44.
(6-11)
In the heat source unit 2 according to the present embodiment, the connection pipe 42 is preferably connected to the low-pressure side of the refrigerant circuit 20.
In this way, the refrigerant container 44 may be connected to the low-pressure side of the refrigerant circuit 20 via the connection pipe 42 and the connecting portion 43.
(6-12)
The refrigeration cycle apparatus 1 according to the present embodiment includes the heat source unit 2 and the utilization unit 3. The heat source unit 2 is any of the above-mentioned heat source units 2. The utilization unit 3 is connected to the heat source unit 2.
The refrigeration cycle apparatus 1 according to the present embodiment can fill the refrigerant circuit 20 with a flammable refrigerant from the refrigerant container 44 that is stably disposed, and can improve safety.

(7) Modifications

(7-1) Modification 1

In the above embodiment, in the second heat exchanger 25, the refrigerant flowing through the refrigerant circuit 20 exchanges heat with the water flowing through the water circuit 30, but the present disclosure is not limited to this example. In this modification, the refrigerant flowing through the refrigerant circuit 20 may exchange heat with the air in the target space. In this case, the water circuit 30 is omitted, and the second heat exchanger 25 is disposed in the target space.

(7-2) Modification 2

In the above embodiment, the casing 41 accommodates the entire refrigerant circuit 20, but the present disclosure is not limited to this example. In this modification, the casing 41 accommodates a part of the refrigerant circuit 20.
While the embodiment of the present disclosure has been described above, it will be understood that various changes in forms and details can be made without departing from the gist and scope of the present disclosure recited in the claims.

REFERENCE SIGNS LIST

1: Refrigeration cycle apparatus
2: Heat source unit
3: Utilization unit
20: Refrigerant circuit
21: Compressor
23: First heat exchanger (heat exchanger)
41: Casing
413: Bottom plate
42: Connection pipe
43: Connecting portion
431: Connecting valve
44: Refrigerant container
45: Cushioning material
46: Protective member
461: Opening
47: Base
471: Elastic member

CITATION LIST

PATENT LITERATURE

Patent Literature 1: JP 2000-28237 A

Claims

A heat source unit (2) comprising:
a refrigerant circuit (20) including a compressor (21) and a heat exchanger (23);

a refrigerant container (44) that is connected to the refrigerant circuit and is filled with a flammable refrigerant;

a connecting portion (43) connected to the refrigerant container;

a connection pipe (42) that connects the connecting portion and the refrigerant circuit; and

a casing (41) that accommodates the compressor, the heat exchanger, the refrigerant container, the connecting portion, and the connection pipe, wherein

the refrigerant container is supported by a bottom plate (413) of the casing.
The heat source unit according to claim 1, wherein
the connecting portion is provided below the refrigerant container.
The heat source unit according to claim 2, further comprising
a protective member (46) that is disposed below the refrigerant container and protects the connecting portion.
The heat source unit according to claim 3, wherein
the connecting portion includes a connecting valve (431) that opens and closes the connection pipe,

the protective member protects the connecting valve, and

the protective member has an opening (461).
The heat source unit according to claim 4, wherein
the opening is provided on a maintenance side.
The heat source unit according to any one of claims 3 to 5, further comprising
a base (47) disposed on a bottom plate of the casing, wherein

the base is in contact with the protective member.
The heat source unit according to claim 6, wherein
the base is fixed to the protective member.
The heat source unit according to claim 6 or 7, wherein
the base includes an elastic member (471) that is in contact with the bottom plate.
The heat source unit according to any one of claims 1 to 8, wherein
the connection pipe includes a capillary (421).
The heat source unit according to any one of claims 1 to 9, further comprising a cushioning material (45) attached to the refrigerant container.
The heat source unit according to any one of claims 1 to 10, wherein
the connection pipe is connected to a low-pressure side of the refrigerant circuit.
A refrigeration cycle apparatus (1) comprising:
the heat source unit according to any one of claims 1 to 11; and

a utilization unit (3) connected to the heat source unit.