WO2007102463A1

WO2007102463A1 - Refrigeration device

Info

Publication number: WO2007102463A1
Application number: PCT/JP2007/054186
Authority: WO
Inventors: Masahiro Yamada; Takahiro Yamaguchi
Original assignee: Daikin Industries, Ltd.
Priority date: 2006-03-06
Filing date: 2007-03-05
Publication date: 2007-09-13
Also published as: KR100960196B1; JP4715561B2; AU2007223486A1; AU2007223486B2; KR20080087902A; CN101384862A; JP2007240026A; EP1992887A4; EP1992887A1; CN101384862B; US20100229582A1

Abstract

A refrigeration device (20) has an intermediate-pressure heat exchanger (40) and a gas-liquid separator (51). In cooling operation, that portion of refrigerant which is condensed in an outdoor heat exchanger (36) flows into injection piping (43). The pressure of the refrigerant flowed into the injection piping (43) is reduced to an intermediate pressure when the refrigerant passes an injection expansion valve (44), and then the refrigerant is supplied to an intermediate pressure port (32) of a compressor (31) after evaporating at the intermediate- pressure heat exchanger (40). In heating operation, the pressure of the refrigerant condensed at an indoor heat exchanger (71) is reduced to an intermediate pressure when the refrigerant passes an indoor expansion valve (72), and then the refrigerant flows into the gas-liquid separator (51). The intermediate-pressure gas refrigerant in the gas-liquid separator (51) is supplied to the intermediate pressure port (32) of the compressor (31).

Description

Specification

Refrigeration equipment

Technical field

[0001] The present invention relates to a refrigeration apparatus that performs gas injection by supplying an intermediate-pressure gas refrigerant to a compressor. Background art

Conventionally, a refrigeration apparatus that performs so-called gas injection (that is, an operation of supplying an intermediate-pressure gas refrigerant to a compressor) is known for the purpose of reducing the input to the compressor. For example, FIG. 1 of Patent Document 1 discloses a refrigeration apparatus that performs a single-stage compression refrigeration cycle and that supplies an intermediate-pressure gas refrigerant to a compression chamber in the middle of compression in a compressor. Further, FIG. 13 of Patent Document 1 discloses a refrigeration apparatus that performs a two-stage compression refrigeration cycle, and supplies an intermediate-pressure gas refrigerant between a low-stage compressor and a high-stage compressor! Speak.

[0003] In order to perform gas injection, an intermediate-pressure gas refrigerant must be generated.

Therefore, for example, in the refrigeration apparatus described in FIG. 1 of Patent Document 1, a gas-liquid separator that separates the intermediate pressure refrigerant into a liquid refrigerant and a gas refrigerant is provided in the refrigerant circuit, and an intermediate is provided from the gas-liquid separator to the compressor. Pressure gas refrigerant is supplied. Further, in the refrigeration apparatus described in FIG. 9 of Patent Document 1, the intermediate-pressure refrigerant is vaporized by exchanging heat with the high-pressure liquid refrigerant in the intermediate-pressure heat exchanger, and is transferred from the intermediate-pressure heat exchanger to the compressor. Supply intermediate pressure gas refrigerant! Patent Document 1: JP 2001-033117 A

Disclosure of the invention

Problems to be solved by the invention

[0004] By the way, in the refrigeration apparatus, components such as a compressor and a heat exchanger provided in the refrigerant circuit may be arranged at positions separated from each other, or may be arranged at different heights. is there. For example, an air conditioner, which is a type of refrigeration system, is often configured by connecting an outdoor unit and an indoor unit through a communication pipe. And when installing an air conditioner in a building, etc., the length of the connecting pipe may reach nearly 100m, or there may be a height difference of about 20-30m between the outdoor unit and the indoor unit. . [0005] As described above, the installation state of the refrigeration apparatus varies depending on the application. The above-described refrigeration apparatus that performs gas injection may not be able to operate smoothly depending on the installation conditions. Hereinafter, this problem will be described.

[0006] As described above, in a refrigeration apparatus that performs gas injection, an intermediate-pressure gas refrigerant may be supplied from a gas-liquid separator to a compressor. Since the liquid refrigerant and the gas refrigerant coexist in the gas-liquid separator, the liquid refrigerant to which the gas-liquid separator force is also sent is saturated. When this type of refrigeration system cools the object, the saturated liquid refrigerant that has flowed out of the gas-liquid separator is sent to the heat exchanger on the use side. However, if the use side heat exchange ^^ is far away from the gas-liquid separator, or if the use-side heat exchanger is installed at a higher position than the gas-liquid separator, the use-side heat exchange ^ While flowing through the pipe toward ^, the refrigerant pressure may drop and some of the refrigerant may evaporate. For this reason, the amount of liquid refrigerant flowing into the use-side heat exchanger decreases, and the cooling capacity obtained by the use-side heat exchanger may decrease.

[0007] Further, in a refrigeration apparatus that performs gas injection, there is a case in which the intermediate pressure refrigerant is heat-exchanged with the high-pressure liquid refrigerant in the intermediate pressure heat exchanger, and the intermediate pressure refrigerant evaporated in the intermediate pressure heat exchanger is supplied to the compressor. is there. When this type of refrigeration apparatus performs an operation of heating an object, a part of the refrigerant condensed in the use side heat exchanger is reduced to an intermediate pressure and introduced into the intermediate pressure heat exchanger. However, if the intermediate pressure heat exchange ^^ is far away from the user side heat exchange ^^ force, or if the intermediate pressure heat exchange ^^ is installed higher than the user side heat exchange ^^, As the refrigerant flows through the pipe toward the intermediate pressure heat exchanger, the refrigerant pressure may drop, and some of the refrigerant may evaporate, causing the refrigerant temperature to drop. For this reason, the temperature difference between the high-pressure refrigerant and the intermediate-pressure refrigerant that exchange heat with each other by the intermediate-pressure heat exchange becomes small, and the intermediate-pressure heat exchanger may not be able to reliably gasify the intermediate-pressure refrigerant.

[0008] The present invention has been made in view of the strong points, and is to enable a smooth operation in a refrigeration apparatus that performs so-called gas injection regardless of the installation state or operation state.

Means for solving the problem

[0009] The first invention includes a compressor (31, 34), a heat source side heat exchanger (36), and a use side heat exchanger (71). The refrigeration cycle is connected and the heat source side heat exchange (36) becomes a condenser and the use side heat exchanger (71) becomes an evaporator, and the use side heat exchanger (71 ) Is a refrigeration apparatus including a refrigerant circuit (20) that can be switched between a heating operation in which the heat source side heat exchanger (36) is an evaporator. The refrigerant circuit (20) includes an instruction passage (43) for supplying intermediate pressure refrigerant obtained by decompressing a part of the high-pressure liquid refrigerant to the compressor (31, 34), and the indication passage (43 ) And an intermediate pressure heat exchanger (40) for evaporating the intermediate pressure refrigerant flowing toward the compressor (31,34) by heat exchange with the high pressure liquid refrigerant and evaporating, and an intermediate pressure obtained by decompressing the high pressure liquid refrigerant. A gas-liquid separator (51) for separating the refrigerant into a liquid refrigerant and a gas refrigerant, and the intermediate-pressure gas refrigerant flowing through the injection passage (43) during the cooling operation is in the heating operation. The flow path of the refrigerant can be changed so that the intermediate-pressure gas refrigerant flowing out of the gas-liquid separator (51) is supplied to the compressor (31, 34), respectively.

[0010] In the first invention, the supply source of the intermediate pressure coolant to the compressor (31, 34) is changed between the cooling operation and the heating operation. During the cooling operation, the intermediate pressure refrigerant evaporated in the intermediate pressure heat exchanger (40) is supplied to the compressor (31, 34). At that time, in the intermediate pressure heat exchanger (40), the high-pressure liquid refrigerant is cooled by heat exchange with the intermediate-pressure refrigerant, so that the degree of supercooling of the high-pressure liquid refrigerant increases. For this reason, even if the pressure of the high-pressure refrigerant drops to some extent from the intermediate pressure heat exchange (40) to the use-side heat exchange (71), the high-pressure refrigerant supplied to the use-side heat exchange (71) is in the liquid state. The amount of high-pressure refrigerant that is kept at the temperature or supplied to the use-side heat exchanger (71) is reduced in the middle. On the other hand, during the heating operation, the intermediate pressure refrigerant is introduced into the gas-liquid separator (51), and the gas refrigerant in the gas-liquid separator (51) is supplied to the compressor (31, 34). For this reason, even if a part of the refrigerant evaporates due to a decrease in the refrigerant pressure from the use side heat exchanger (71) to the gas-liquid separator (51), the gas-liquid separator (51) Since the gas refrigerant and the liquid refrigerant are separated, the intermediate-pressure gas refrigerant is reliably supplied to the compressor (31, 34).

[0011] In a second aspect based on the first aspect, the refrigerant circuit (20) is a heat source side circuit provided with the compressor (31, 34) and the heat source side heat exchanger (36). (30) and the use side circuit (70) provided with the use side heat exchanger (71) are connected by connecting pipes (21, 22), and the injection passage (43), Intermediate pressure heat exchanger (40) and above A gas-liquid separator (51) is provided in the heat source side circuit (30).

[0012] In the second invention, the refrigerant circuit (20) includes the heat source side circuit (30), the use side circuit (70), and the connection pipes (21, 22). During the cooling operation, the high-pressure liquid refrigerant cooled when passing through the intermediate pressure heat exchanger (40) flows into the use side heat exchanger (71) through the connecting pipe (21). For this reason, even if the connecting pipe (21, 22) is long or the user circuit (70) is installed at a higher position than the heat source circuit (30), the user heat exchanger (71) The high-pressure refrigerant supplied to is kept in a liquid state, or the amount of high-pressure refrigerant supplied to the use-side heat exchanger (71) is reduced in the middle. On the other hand, during the heating operation, the refrigerant condensed in the use side heat exchange (71) flows into the gas-liquid separator (51) through the communication pipe (21), and the gas refrigerant in the gas-liquid separator (51) Is supplied to the compressor (31, 34). Therefore, even if the connecting pipe (21, 22) is long or the heat source side circuit (30) is installed at a higher position than the user side circuit (70), the compressor (31, 34) ) Is reliably supplied to the gas refrigerant.

[0013] In a third aspect based on the first aspect, the gas-liquid separator (51) is the refrigerant circuit.

(20) of the container shape disposed at a position downstream of the heat source side heat exchanger (36) during the cooling operation and downstream of the use side heat exchanger (71) during the caloric heat operation. On the other hand, the intermediate pressure heat exchanger (40) is constituted by a member (65), and the intermediate pressure refrigerant accommodated in the container-like member (65) and flows through the injection passage (43) is supplied to the container-like member. The heat exchange member (66) is configured to exchange heat with the liquid refrigerant in (65).

In the third invention, the gas-liquid separator (51) is constituted by the container-like member (65), and the intermediate pressure heat exchanger (40) is constituted by the heat exchange member (66). In the cooling operation, the refrigerant (high-pressure liquid refrigerant) condensed in the heat source side heat exchanger (36) flows into the container-like member (65). A part of the high-pressure liquid refrigerant flows into the injection passage (43), is reduced to an intermediate pressure, and flows into the heat exchange member. The intermediate-pressure refrigerant flowing into the heat exchange member evaporates by exchanging heat with the high-pressure liquid refrigerant in the container-like member (65), and then supplied to the compressor (31, 34). The high-pressure liquid refrigerant in the container-like member (65) cooled by heat exchange with the intermediate-pressure refrigerant is sent to the container-like member (65) toward the use side heat exchanger (71). On the other hand, in the heating operation, the refrigerant condensed in the use side heat exchanger (71) is reduced to an intermediate pressure in the container-like member (65). It flows in after it is. In the container-like member (65), the flowing intermediate pressure refrigerant is separated into a liquid refrigerant and a gas refrigerant. From the heat source side heat exchanger (36), the liquid refrigerant is sent out toward the heat source side heat exchanger (36), and is supplied to the compressors (31, 34) through the gas refrigerant injection passage (43).

[0015] In a fourth aspect based on the first aspect, the refrigerant circuit (20) has a high-pressure liquid refrigerant at a position downstream of the intermediate pressure heat exchanger (40) during the cooling operation. A supercooling heat exchange (60) force S is provided to cool the high-pressure liquid refrigerant by exchanging heat with a low-pressure refrigerant obtained by reducing a part of the pressure to a low pressure.

[0016] In the fourth invention, the supercooling heat exchanger (60) is provided in the refrigerant circuit (20). During the cooling operation, the supercooling heat exchanger (60) exchanges heat with the low-pressure refrigerant obtained by decompressing a part of the high-pressure liquid refrigerant that has passed through the intermediate-pressure heat exchanger (40). Cooled by. That is, in the supercooling heat exchanger (60), the degree of supercooling of the high-pressure liquid refrigerant is increased. The high-pressure liquid refrigerant cooled by the subcooling heat exchanger (60) is sent to the use side heat exchanger (71).

[0017] In a fifth aspect based on the first aspect, the refrigerant circuit (20) performs a single-stage compression refrigeration cycle, while the compressor (31) transfers intermediate pressure to a compression chamber in the middle of compression. The gas refrigerant is configured to flow in.

[0018] In the fifth invention, the intermediate-pressure gas refrigerant is introduced into the compression chamber in the middle of compression in the compressor (31). The compressor (31) is a evaporator of the use side heat exchanger (71) and the heat source side heat exchanger (36)! 40) or the intermediate pressure refrigerant supplied from the gas-liquid separator (51) is sucked and compressed.

[0019] In a sixth aspect of the present invention based on the first aspect, the refrigerant circuit (20) includes a low-stage compressor (33) and a high-stage compressor (34) connected in series. While the stage compression refrigeration cycle is performed, the refrigerant circuit (20) is configured to supply an intermediate pressure gas refrigerant to the suction side of the high stage compressor (34).

[0020] In the sixth invention, the intermediate-pressure gas refrigerant is introduced to the suction side of the high-stage compressor (34). The high-stage compressor (34) includes the refrigerant compressed by the low-stage compressor (33) and the gas sent from the intermediate pressure heat exchanger (40) and gas-liquid separator (51). Inhale refrigerant.

The invention's effect In the present invention, during the cooling operation, the intermediate pressure refrigerant evaporated by the intermediate pressure heat exchanger (40) is supplied to the compressor (31, 34) and cooled by the intermediate pressure heat exchanger (40). The high-pressure liquid refrigerant is sent to the use side heat exchanger (71). For this reason, the use side heat exchanger (71) is located far away from the intermediate pressure heat exchanger (40) !, or the use side heat exchanger (71) is from the intermediate pressure heat exchanger (40). Even in an installation situation where the pressure of the high-pressure refrigerant is reduced from the intermediate pressure heat exchange (40) to the use side heat exchanger (71), The high-pressure refrigerant supplied to the user-side heat exchanger (71) can be kept in a liquid state, or the amount of high-pressure refrigerant supplied to the user-side heat exchanger (71) can be reduced in the middle. . As a result, the amount of liquid refrigerant supplied to the use side heat exchanger (71) during the cooling operation can be ensured, and the cooling capacity of the use side heat exchange (71) can be fully exhibited.

[0022] Further, in the present invention, during the heating operation, the gas-liquid separator (51) force is also supplying the intermediate-pressure gas refrigerant to the compressor (31, 34). For this reason, the gas-liquid separator (51) is located far away from the user-side heat exchanger (71), or the gas-liquid separator (51) is higher than the user-side heat exchanger (71)! Even in an installation situation where the refrigerant pressure drops considerably from the use side heat exchanger (71) to the gas-liquid separator (51), the intermediate-pressure gas refrigerant is pressurized. It can be reliably supplied to the compressor (31, 34). As a result, it is possible to avoid a situation in which the intermediate-pressure liquid refrigerant flows into the compressor (31, 34) and causes damage to the compressor (31, 34).

[0023] Thus, according to the present invention, the refrigeration apparatus (10) can be used during both the cooling operation and the heating operation regardless of the state in which the refrigeration apparatus (10) is installed. Smooth operation is possible.

In the second invention, the refrigerant circuit (20) is constituted by the heat source side circuit (30), the use side circuit (70), and the communication pipes (21, 22). In this case, the heat source side circuit (30) provided with the intermediate pressure heat exchange (40) and the gas-liquid separator (51), and the use side circuit (70) provided with the use side heat exchange (71). ) Are often placed at distant locations, or they are installed at different heights. Therefore, in the refrigeration apparatus (10) including the refrigerant circuit (20) configured as in the present invention, as described above, the intermediate pressure refrigerant for the compressor (31, 34) is being cooled and heated. Changing the supplier may ease restrictions on the installation status of the refrigeration system (10). it can.

[0025] In the third invention, the heat exchange member (66) constituting the intermediate pressure heat exchanger (40) is accommodated inside the container-like member (65) constituting the gas-liquid separator (51). ing. In other words, if the container-like member (65) containing the heat exchange member (66) is connected to the refrigerant circuit (20), both the gas-liquid separator (51) and the intermediate pressure heat exchanger (40) It is installed in the refrigerant circuit (20). Therefore, according to the present invention, the configuration of the refrigerant circuit (20) can be simplified as compared with the case where the gas-liquid separator (51) and the intermediate pressure heat exchanger (40) are individually formed.

[0026] In the fourth aspect, the supercooling heat exchanger (60) is provided in the refrigerant circuit (20), and the degree of supercooling of the high-pressure liquid refrigerant sent to the use side heat exchanger (71) during the cooling operation is determined. Increase it! For this reason, even if the installation condition is such that the pressure force S of the high-pressure refrigerant decreases from the intermediate pressure heat exchanger (40) to the user-side heat exchanger (71), the user-side heat exchanger (71) The supplied high-pressure refrigerant can be more reliably maintained in a liquid state, or the amount of the high-pressure refrigerant supplied to the use side heat exchanger (71) can be further reduced.

Brief Description of Drawings

FIG. 1 is a piping system diagram showing a configuration of a refrigerant circuit of an air conditioner in Embodiment 1, wherein (A) shows a state during cooling operation, and (B) shows a state during heating operation. Showing

FIG. 2 is a piping system diagram showing a configuration of a refrigerant circuit of an air conditioner in Embodiment 2, in which (A) shows a state during cooling operation, and (B) shows a state during heating operation. RU

FIG. 3 is a distribution system diagram showing a configuration of a refrigerant circuit of an air conditioner in a first modification of the other embodiment, where (A) shows a state during cooling operation, and (B) shows heating. The state during operation is shown.

FIG. 4 is a piping system diagram showing a configuration of a refrigerant circuit of an air conditioner in a second modification of the other embodiment, where (A) shows a state during cooling operation, and (B) shows heating. The state during operation is shown.

Explanation of symbols

[0028] 20 Refrigerant circuit

21 Liquid side connection piping

22 Gas side communication piping 30 Outdoor circuit (heat source side circuit)

31 Compressor

33 Low stage compressor

34 High stage compressor

36 Outdoor heat exchanger (heat source side heat exchanger)

40 Intermediate pressure heat exchange

43 Injection piping (injection passage)

51 Gas-liquid separator

65 Container

66 Heat exchange components

70 Indoor circuit (use side circuit)

71 Indoor heat exchange (user side heat exchange)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Embodiment 1 of the Invention]

Embodiment 1 of the present invention will be described. The present embodiment is an air conditioner (10) configured by a refrigeration apparatus according to the present invention.

As shown in FIG. 1, the air conditioner (10) of the present embodiment includes one outdoor unit (11) and two indoor units (12). The number of indoor units (12) is merely an example. The outdoor unit (11) accommodates an outdoor circuit (30) that is a heat source side circuit (30). Each indoor unit (12) accommodates an indoor circuit (70) which is a use side circuit.

[0032] In the air conditioner (10), the refrigerant circuit (20) is formed by connecting the outdoor circuit (30) and the indoor circuit (70) by the liquid side connecting pipe (21) and the gas side connecting pipe (22). Te! In this refrigerant circuit (20), two indoor circuits (70) are connected in parallel to one outdoor circuit (30).

[0033] Each indoor circuit (70) is provided with one indoor heat exchanger (71) as a use side heat exchanger and one indoor expansion valve (72). Indoor heat exchange (71) is air heat exchange that exchanges heat between indoor air and refrigerant. In each indoor circuit (70), indoor heat exchange (71) and indoor expansion The tension valves (72) are connected in series with each other. In each indoor circuit (70), the liquid side communication pipe (21) is connected to the end on the indoor expansion valve (72) side, and the gas side communication pipe (22) is connected to the end on the indoor heat exchanger (71) side. Is connected!

[0034] The outdoor circuit (30) includes a compressor (31), a four-way switching valve (35), an outdoor heat exchanger (36) as a heat source side heat exchanger, an outdoor expansion valve (37), An accumulator (38) is provided. The outdoor heat exchanger (36) includes an intermediate pressure heat exchanger (40), a gas-liquid separator (51), a bypass pipe (50), an injection pipe (43), and an intermediate pressure gas. Piping (52) is provided.

[0035] The compressor (31) is a positive displacement compressor (31) and is configured to compress the refrigerant sucked into the compression chamber. The compressor (31) is provided with an intermediate pressure port (32) for introducing an intermediate pressure refrigerant into the compression chamber in the middle of compression. The compressor (31) has its discharge side connected to the first port of the four-way switching valve (35) and its suction side connected to the second port of the four-way switching valve (35) via the accumulator (38). ing. In the present embodiment, only one compressor (31) is provided in the outdoor circuit (30), but a plurality of compressors may be provided in parallel.

[0036] The outdoor heat exchanger (36) is an air heat exchanger for exchanging heat between outdoor air and the refrigerant. The intermediate pressure heat exchanger (40) is a heat exchanger that exchanges heat between refrigerants such as a double-pipe heat exchanger and a plate heat exchanger. In this intermediate pressure heat exchange (40), a first channel (41) and a second channel (42) are formed. The outdoor heat exchanger (36) has one end connected to the third port of the four-way switching valve (35) and the other end connected to the first flow path of the intermediate pressure heat exchanger (40) via the outdoor expansion valve (37). (41) is connected to one end of each. The other end of the first flow path (41) of the intermediate pressure heat exchanger (40) is connected to the liquid side communication pipe (21) via the first check valve (45). The first check valve (45) is arranged so as to allow only the flow of the refrigerant directed to the intermediate pressure heat exchange (40) force liquid side communication pipe (21).

[0037] The injection pipe (43) forms an injection passage. The injection pipe (43) has its start end connected between the intermediate pressure heat exchanger (40) and the first check valve (45), and its end connected to the intermediate pressure port (32) of the compressor (31). Has been. The second flow path (42) of the intermediate pressure heat exchanger (40) is disposed in the middle of the instruction pipe (43). Inji In the case pipe (43), an injection expansion valve (44) is provided between the starting end of the case pipe (43) and the second flow path (42) of the intermediate pressure heat exchange (40).

[0038] The gas-liquid separator (51) is a sealed container formed in a vertically long cylindrical shape. The gas-liquid separator (51) has a lower end arranged in the middle of the bypass pipe (50). The no-pass pipe (50) has a leading end between the first check valve (45) and the liquid side connecting pipe (21) and a terminal end connected to the first flow path (41) of the intermediate pressure heat exchanger (40). Each is connected between the outdoor expansion valves (37). In the bypass pipe (50), a second check valve (55) is provided between the terminal end of the bypass pipe (50) and the gas-liquid separator (51). The second check valve (55) is arranged so as to allow only the flow of the refrigerant in the direction in which the gas-liquid separator (51) force also flows out.

[0039] One end of an intermediate pressure gas pipe (52) is connected to the top of the gas-liquid separator (51). The other end of the intermediate pressure gas pipe (52) is connected between the second flow path (42) of the intermediate pressure heat exchange (40) in the injection pipe (43) and the compressor (31). A solenoid valve (53) is provided in the middle of the intermediate pressure gas pipe (52).

[0040] As described above, the four-way selector valve (35) has a first port on the discharge side of the compressor (31), a second port on the accumulator (38), and a third port on the outdoor heat. Each is connected to the reversal (36). The fourth port of the four-way selector valve (35) is connected to the gas side communication pipe (22). This four-way switching valve (35) has a first state (the state shown in FIG. 1 (A)) in which the first port and the third port communicate with each other, and the second port and the fourth port communicate with each other. Switch to the 2nd state (state shown in Fig. 1 (B)) where the 1 port communicates with the 4th port and the 2nd port communicates with the 3rd port.

[0041] Driving operation

The air conditioner (10) can be switched between cooling operation and heating operation!

[0042] <Cooling operation>

The operation during cooling operation will be described with reference to FIG. 1 (A). In the refrigerant circuit (20) during the cooling operation, the refrigerant circulates so that the outdoor heat exchanger (36) serves as a condenser and the indoor heat exchanger (71) serves as an evaporator. That is, the cooling operation is performed in the refrigerant circuit (20).

[0043] Specifically, during the cooling operation, the four-way selector valve (35) is set to the first state. In addition, the outdoor expansion valve (37) is set to the fully open state, and the injection expansion valve (44) and the indoor expansion valve ( The opening degree of 72) is adjusted as appropriate, and the solenoid valve (53) is closed.

[0044] The high-pressure gas refrigerant discharged from the compressor (31) releases heat to the outdoor air and condenses in the outdoor heat exchanger (36). The high-pressure liquid refrigerant from the outdoor heat exchanger (36) dissipates heat to the refrigerant in the second flow path (42) while passing through the first flow path (41) of the intermediate pressure heat exchanger (40). . The high-pressure liquid refrigerant that also flowed out of the first flow path (41) of the intermediate pressure heat exchanger (40) flows into the partial force S-injection pipe (43), and the rest passes through the liquid side connecting pipe (21). Distributed to each indoor circuit (70).

[0045] In each indoor circuit (70), the high-pressure liquid refrigerant that has flowed in is reduced in pressure when passing through the indoor expansion valve (72), and is then evaporated by absorbing the indoor aerodynamic force in the indoor heat exchanger (71). The refrigerant evaporated in the indoor heat exchanger (71) returns to the outdoor circuit (30) through the gas side connecting pipe (22), and is sucked into the compressor (31) through the accumulator (38). .

On the other hand, the high-pressure liquid refrigerant that has flowed into the injection pipe (43) is reduced to an intermediate pressure when passing through the injection expansion valve (44) to become a gas-liquid two-phase intermediate pressure refrigerant. This intermediate pressure refrigerant absorbs heat from the refrigerant in the first flow path (41) and evaporates while flowing through the second flow path (42) of the intermediate pressure heat exchanger (40). The intermediate pressure gas refrigerant exiting from the second flow path (42) of the intermediate pressure heat exchanger (40) is sent to the intermediate pressure port (32) of the compressor (31).

[0047] The compressor (31) sucks the low-pressure refrigerant into the compression chamber through the accumulator (38) and compresses it. In addition, the intermediate pressure gas refrigerant flowing from the intermediate pressure port (32) is introduced into the compression chamber in the middle of compression. The compressor (31) compresses the refrigerant in the compression chamber to a high pressure and discharges it.

[0048] Thus, during the cooling operation, the high-pressure liquid refrigerant that has been cooled when passing through the intermediate pressure heat exchanger (40) and has a high degree of supercooling passes through the liquid side communication pipe (21) to the room. Sent to circuit (70). For this reason, the length of the liquid side connecting pipe (21) is more than a certain length, or the indoor circuit (70) is placed at a position that is a little higher than the outdoor circuit (30). If the liquid refrigerant sent from (30) to the liquid side connection pipe (21) is saturated, even if a part of the high-pressure liquid refrigerant evaporates before reaching the indoor circuit (70), The high-pressure refrigerant flowing into the inner circuit (70) is maintained in the liquid single phase state. Even if a part of the high-pressure liquid refrigerant evaporates before reaching the indoor circuit (70), the liquid refrigerant sent from the outdoor circuit (30) to the liquid side connection pipe (21) is more saturated. Evaporating high pressure liquid The amount of refrigerant decreases.

[0049] <Heating operation>

The operation during heating operation will be described with reference to FIG. 1 (B). In the refrigerant circuit (20) during the heating operation, the refrigerant circulates so that the indoor heat exchanger (71) serves as a condenser and the outdoor heat exchanger (36) serves as an evaporator. That is, a heating operation is performed in the refrigerant circuit (20).

[0050] Specifically, during the heating operation, the four-way selector valve (35) is set to the second state. In addition, the opening degree of the outdoor expansion valve (37) and the indoor expansion valve (72) is adjusted as appropriate, the indication expansion valve (44) is set to the fully closed state, and the electromagnetic valve (53) is opened. .

[0051] Compressor (31) Force The discharged high-pressure gas refrigerant is distributed to each indoor circuit (70) through the gas side connecting pipe (22). In the indoor heat exchanger (71) of each indoor circuit (70), the high-pressure gas refrigerant dissipates heat to the indoor air and condenses. In each indoor circuit (70), the refrigerant flowing out of the indoor heat exchanger (71) is reduced in pressure when passing through the indoor expansion valve (72) to become a gas-liquid two-phase intermediate pressure refrigerant. The intermediate pressure refrigerant flowing out of each indoor circuit (70) returns to the outdoor circuit (30) through the liquid side connecting pipe (21) and flows into the gas-liquid separator (51) through the bypass pipe (50). The

[0052] Among the intermediate pressure refrigerant that has flowed into the gas-liquid separator (51), the liquid refrigerant is collected in the lower part of the gas-liquid separator (51), and the gas refrigerant is accumulated in the upper part of the gas-liquid separator (51). The intermediate-pressure liquid refrigerant in the gas-liquid separator (51) flows again through the bypass pipe (50) and is reduced in pressure when passing through the outdoor expansion valve (37) before being introduced into the outdoor heat exchanger (36). The In the outdoor heat exchanger (36), the refrigerant absorbs outdoor air force and evaporates. The refrigerant evaporated in the outdoor heat exchange (36) is sucked into the compressor (31) through the accumulator (38). On the other hand, the intermediate-pressure gas refrigerant in the gas-liquid separator (51) is introduced into the intermediate-pressure port (32) of the compressor (31) through the intermediate-pressure gas pipe (52) and the instruction pipe (43) in this order. The

[0053] The compressor (31) sucks and compresses the low-pressure refrigerant into the compression chamber through the accumulator (38). In addition, the intermediate pressure gas refrigerant flowing from the intermediate pressure port (32) is introduced into the compression chamber in the middle of compression. The compressor (31) compresses the refrigerant in the compression chamber to a high pressure and discharges it.

[0054] Thus, during the heating operation, the liquid side communication pipe (21) is returned to the outdoor circuit (30). The refrigerant is introduced into the gas-liquid separator (51) and separated into liquid refrigerant and gas refrigerant, and only the gas refrigerant in the gas-liquid separator (51) is supplied to the intermediate pressure port (32) of the compressor (31). is doing. That is, even when the refrigerant flowing into the outdoor circuit (30) is in a gas-liquid two-phase state, only the gas refrigerant is reliably supplied to the intermediate pressure port (32) of the compressor (31). For this reason, the liquid side communication pipe (21) is longer than the length, or the outdoor circuit (30) is higher than the indoor circuit (70) to some extent! Even if a part of the refrigerant evaporates before reaching the circuit (70), the refrigerant flowing into the intermediate pressure port (32) of the compressor (31) is kept in a gas single-phase state. .

[0055] Effect of Embodiment 1

During the cooling operation of the air conditioner (10), the intermediate pressure refrigerant evaporated by the intermediate pressure heat exchanger (40) is supplied to the intermediate pressure port (32) of the compressor (31) for intermediate pressure heat exchange. The high-pressure liquid refrigerant cooled by the vessel (40) is supplied to the indoor circuit (70). For this reason, the liquid side connecting pipe (21) connecting the outdoor circuit (30) and the indoor circuit (70) is extremely long, or the indoor circuit (70) is arranged at a position higher than the outdoor circuit (30). Thus, the high-pressure refrigerant supplied to the indoor circuit (70) can be kept in a liquid state even in an installation situation in which the refrigerant pressure drops significantly while flowing through the liquid side connecting pipe (21). Alternatively, the amount of high-pressure refrigerant supplied to the indoor circuit (70) that evaporates in the middle can be reduced. As a result, the amount of liquid refrigerant supplied to the indoor circuit (70) during the cooling operation can be secured, and the cooling capacity of the indoor unit (12) can be fully exhibited.

[0056] Here, when a plurality of indoor circuits (70) are connected in parallel to each other as in the air conditioner (10), in order to appropriately adjust the cooling capacity of each indoor unit (12), The refrigerant distribution ratio to the indoor circuit (70) is adjusted by individually controlling the opening of the indoor expansion valve (72) of each indoor circuit (70). However, if the refrigerant passing through the indoor expansion valve (72) enters a gas-liquid two-phase state, the flow characteristics of the indoor expansion valve (72) become unstable, and the distribution ratio of the refrigerant to each indoor circuit (70) becomes appropriate. May be out of control. In contrast, in the air conditioner (10) of the present embodiment, the refrigerant flowing into the indoor circuit (70) during the cooling operation can be easily held in a liquid state. Therefore, according to the present embodiment, in the air conditioner (10) including the plurality of indoor units (12), the cooling capacity of each indoor unit (12) can be accurately controlled. [0057] During the heating operation of the air conditioner (10), the refrigerant returned from the indoor circuit (70) to the outdoor circuit (30) is separated into liquid refrigerant and gas refrigerant by the gas-liquid separator (51). However, only the intermediate-pressure gas refrigerant is supplied from the gas-liquid separator (51) to the compressor (31). For this reason, the liquid side connecting pipe (21) connecting the outdoor circuit (30) and the indoor circuit (70) is extremely long, or the outdoor circuit (30) is positioned higher than the indoor circuit (70). Therefore, even in an installation situation where the pressure of the refrigerant greatly decreases while flowing through the liquid side connecting pipe (21), the gas refrigerant is connected to the intermediate pressure port (32) of the compressor (31). Can only be reliably supplied. As a result, if the intermediate-pressure liquid refrigerant flows into the compressor (31) and causes the compressor (31) to be damaged!

[0058] Thus, according to this embodiment, the air conditioner (10) can be installed in both the cooling operation and the heating operation regardless of the state of installation! The air conditioner (10) can be operated smoothly.

[Embodiment 2 of the Invention]

Embodiment 2 of the present invention will be described. In this embodiment, a supercooling heat exchanger (60) and a supercooling pipe (63) are added to the air conditioner (10) of the first embodiment. Here, regarding the air conditioner (10) of the present embodiment, differences from the first embodiment will be described.

[0060] As shown in FIG. 2, the supercooling heat exchange (60) is provided in the outdoor circuit (30). The subcooling heat exchanger (60) is a heat exchange that exchanges heat between refrigerants such as a double-pipe heat exchanger and a plate heat exchanger. In this supercooling heat exchanger (60), a first channel (61) and a second channel (62) are formed. The first flow path (61) of the supercooling heat exchanger (60) is provided between the intermediate pressure heat exchanger (40) and the first check valve (45) in the outdoor circuit (30).

[0061] The supercooling pipe (63) has a start end between the supercooling heat exchanger (60) and the first check valve (45), and a terminal end of the accumulator (38) and the four-way switching valve (35). Each connected in between. The second flow path (62) of the supercooling heat exchanger (60) is disposed in the middle of the supercooling pipe (63). In the supercooling pipe (63), a supercooling expansion valve (64) is provided between its starting end and the second flow path (62) of the supercooling heat exchanger (60).

[0062] Driving operation

As shown in FIG. 2 (A), in the refrigerant circuit (20) during the cooling operation, the case of the first embodiment and In general, the refrigerant circulates in the same manner. Specifically, the high-pressure liquid refrigerant that has flowed out of the intermediate-pressure heat exchanger (40) flows into the liquid-side connecting pipe (21) after passing through the supercooling heat exchanger (60), and part of the high-pressure liquid refrigerant. Only the point that the refrigerant flows into the supercooling pipe (63) is different from the refrigerant circulation path in the first embodiment.

[0063] In the cooling operation of the air conditioner (10) of the present embodiment, the opening degree of the supercooling expansion valve (64) is appropriately adjusted. The high-pressure liquid refrigerant flowing out from the first flow path (41) of the intermediate pressure heat exchanger (40) passes through the first flow path (61) of the subcooling heat exchanger (60) while passing through the second flow path. Dissipates heat to refrigerant (62). The first flow path (61) force of the supercooling heat exchange (60) part of the high-pressure liquid refrigerant that has flowed out flows into the supercooling pipe (63) and the rest passes through the liquid side connecting pipe (21). Distributed to each indoor circuit (70). That is, the indoor circuit (70) is supplied with the high-pressure liquid refrigerant cooled by both the intermediate pressure heat exchange (40) and the supercooling heat exchange (60).

[0064] On the other hand, the high-pressure liquid refrigerant that has flowed into the supercooling pipe (63) is reduced to a low pressure when passing through the supercooling expansion valve (64) to become a low-pressure refrigerant in a gas-liquid two-phase state. This low-pressure refrigerant absorbs heat from the refrigerant in the first channel (61) and evaporates while flowing through the second channel (62) of the supercooling heat exchanger (60). The low-pressure gas refrigerant generated in the second flow path (62) of the supercooling heat exchanger (60) returned from the indoor circuit (70) to the outdoor circuit (30) through the gas side connection pipe (22). It is sucked into the compressor (31) together with the low-pressure refrigerant.

[0065] <Heating operation>

As shown in FIG. 2 (B), in the refrigerant circuit (20) during the heating operation, the refrigerant circulates in exactly the same manner as in the first embodiment. Specifically, during the heating operation, the supercooling expansion valve (64) is fully closed. The intermediate pressure refrigerant flowing from the liquid side connection pipe (21) into the outdoor circuit (30) flows into the gas-liquid separator (51) through the bypass pipe (50) and is separated into the liquid refrigerant and the gas refrigerant. It is.

[0066] Effect of Embodiment 2

In the present embodiment, the supercooling heat exchanger (60) is provided in the outdoor circuit (30) to increase the degree of superheat of the high-pressure liquid refrigerant sent to the indoor circuit (70) during the cooling operation. For this reason, even in an installation situation in which the pressure of the high-pressure refrigerant decreases from the outdoor circuit (30) to the indoor circuit (70), the high-pressure refrigerant supplied to the indoor circuit (70) is more reliably liquefied. In keeping the condition Or the amount of high-pressure refrigerant supplied to the indoor circuit (70) that evaporates in the middle can be further reduced.

[0067] << Other Embodiments >>

According to the above embodiment, the following configuration may be adopted.

[0068] First modification

In each of the above embodiments, the gas-liquid separator (51) and the intermediate pressure heat exchanger (40) may be integrated. Here, what applied this modification to the air conditioner (10) of the said Embodiment 2 is demonstrated, referring FIG.

[0069] The gas-liquid separator (51) of the present modification is configured by a container-like member (65) formed in a slightly vertically long cylindrical shape. The bottom of the container-like member (65) constituting the gas-liquid separator (51) is connected to a portion of the outdoor circuit (30) between the outdoor expansion valve (37) and the supercooling heat exchanger (60). ing. In the outdoor circuit (30) of this modification, the bypass pipe (50), the first check valve (45), and the second check valve (55) may be omitted.

[0070] Inside the container-like member (65), a heat exchange member (66) in which a heat transfer tube is formed in a coil spring shape is provided. The heat exchange member (66) is disposed at the bottom of the container-like member (65) so as to be immersed in the liquid refrigerant accumulated in the container-like member (65). The heat exchange member (66) is disposed on the downstream side of the injection expansion valve (44) in the injection pipe (43). In this modification, this heat exchange member (66) constitutes an intermediate pressure heat exchanger (40).

[0071] The operation during the cooling operation will be described. During the cooling operation, as in the case of the second embodiment, the opening degrees of the index expansion valve (44) and the supercooling expansion valve (64) are appropriately adjusted, and the electromagnetic valve (53) is closed.

[0072] During the cooling operation, the refrigerant condensed in the outdoor heat exchanger (36) passes through the fully-expanded outdoor expansion valve (37) and flows into the container-like member (65). The high-pressure liquid refrigerant in the container-like member (65) radiates heat to the intermediate-pressure refrigerant flowing in the heat exchange member (66). That is, in the container-like member (65), the high-pressure liquid refrigerant is cooled by heat exchange with the intermediate-pressure refrigerant in the heat exchange member (66), and the degree of supercooling of the high-pressure liquid refrigerant increases. The high-pressure liquid refrigerant cooled in the container-like member (65) flows into the partial force injection pipe (43), and the rest is subcooled heat exchanger (60). It is further cooled while passing through the first flow path (61).

[0073] The high-pressure liquid refrigerant cooled by the supercooling heat exchanger (60) is supplied to the indoor circuit (70) through the liquid-side connecting pipe (21). On the other hand, the high-pressure liquid refrigerant that has flowed into the injection pipe (43) is reduced to an intermediate pressure when passing through the injection expansion valve (44), and is sent to the heat exchange member (66) as an intermediate-pressure refrigerant. It is done. The intermediate pressure refrigerant flowing into the heat exchange member (66) absorbs the high-pressure liquid refrigerant in the container-like member (65) and evaporates, and then is supplied to the intermediate pressure port (32) of the compressor (31). Is done.

[0074] The operation during the heating operation will be described. During the heating operation, as in the case of the second embodiment, the injection expansion valve (44) and the supercooling expansion valve (64) are fully closed and the electromagnetic valve (53) is opened.

[0075] During the heating operation, the refrigerant condensed in the indoor heat exchanger (71) is reduced to an intermediate pressure when passing through the indoor expansion valve (72), and is then passed through the liquid side communication pipe (21). It passes through the first flow path (61) of the cooling heat exchanger (60) in order and flows into the container-like member (65). In the container-like member (65), the gas-liquid two-phase intermediate pressure refrigerant is separated into liquid refrigerant and gas refrigerant. The intermediate-pressure gas refrigerant accumulated in the upper part of the container-like member (65) is supplied to the intermediate-pressure port (32) of the compressor (31) through the instruction pipe (43). The intermediate-pressure liquid refrigerant accumulated in the lower part of the container-like member (65) is reduced to a low pressure when passing through the outdoor expansion valve (37) and then introduced into the outdoor heat exchanger (36).

[0076] As described above, in this variation, the heat exchange member (66) constituting the intermediate pressure heat exchanger (40) is replaced by the container-like member (65) constituting the gas-liquid separator (51). Housed inside. In other words, if the container-like member (65) that houses the heat exchange member (66) is connected to the outdoor circuit (30), both the gas-liquid separator (51) and the intermediate pressure heat exchanger (40) are connected outdoors. It is installed in the circuit (30). Therefore, according to this modification, the configuration of the outdoor circuit (30) can be simplified as compared with the case where the gas-liquid separator (51) and the intermediate pressure heat exchanger (40) are individually formed. .

[0077] Second modification

In each of the above embodiments, the low-stage compressor (33) and the high-stage compressor (34) are installed in the outdoor circuit (30), and the refrigerant circuit (20) performs the two-stage compression refrigeration cycle. Also good. Here, FIG. 4 is referred to for the case where the present modification is applied to the air conditioner (10) of the second embodiment. I will explain.

[0078] In the outdoor circuit (30) of this modification, the low-stage compressor (33) and the high-stage compressor (34) are connected in series. Specifically, the suction side of the low-stage compressor (33) is connected to the second port of the four-way switching valve (35) via the accumulator (38). The discharge side of the low stage compressor (33) is connected to the suction side of the high stage compressor (34). The discharge side of the high stage compressor (34) is connected to the first port of the four-way selector valve (35). In this modification, the end of the injection pipe (43) is connected to a pipe connecting the discharge side of the low stage compressor (33) and the suction side of the high stage compressor (34). The intermediate-pressure gas refrigerant flowing through the injection pipe (43) is drawn into the high-stage compressor (34) together with the intermediate-pressure refrigerant discharged from the low-stage compressor (33).

Note that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

Industrial applicability

[0080] As described above, the present invention is useful for a refrigeration apparatus that performs gas injection by supplying an intermediate-pressure gas refrigerant to a compressor.

Claims

The scope of the claims

[1] The compressor (31, 34), the heat source side heat exchange (36) and the use side heat exchange (71) are connected to perform a refrigeration cycle, and the heat source side heat exchange (36) is connected to the condenser. The cooling operation in which the use side heat exchanger (71) becomes an evaporator, and the use side heat exchanger (71) becomes a condenser, and the heat source side heat exchanger (36) becomes an evaporator. A refrigeration apparatus comprising a refrigerant circuit (20) capable of switching between heating operations,

The refrigerant circuit (20)

An injection passage (43) for supplying intermediate pressure refrigerant obtained by decompressing a part of the high-pressure liquid refrigerant to the compressor (31, 34), and the injection passage (43) serve as the compressor (31, 34). An intermediate pressure heat exchanger (40) that evaporates the intermediate pressure refrigerant flowing toward the high pressure liquid refrigerant by heat exchange with the high pressure liquid refrigerant, and separates the intermediate pressure refrigerant obtained by depressurizing the high pressure liquid refrigerant into liquid refrigerant and gas refrigerant Gas-liquid separator (51)

During the cooling operation, the intermediate-pressure gas refrigerant flowing through the injection passage (43). During the heating operation, the gas-liquid separator (51) force is discharged. Refrigerant distribution path can be changed to be supplied to (31,34)

A refrigeration apparatus characterized by that.

[2] In claim 1,

The refrigerant circuit (20) includes a heat source side circuit (30) provided with the compressor (31, 34) and the heat source side heat exchanger (36) and a use side provided with the use side heat exchanger (71). Side circuit (70) and connecting pipe (21, 22)

The injection passage (43), the intermediate pressure heat exchanger (40), and the gas-liquid separator (51) are provided in the heat source side circuit (30).

A refrigeration apparatus characterized by that.

[3] In claim 1,

The gas-liquid separator (51) is located downstream of the heat source side heat exchanger (36) during the cooling operation in the refrigerant circuit (20), and the use side heat exchanger (71) during the heating operation. While being constituted by a container-like member (65) arranged at a position downstream of The intermediate pressure heat exchanger (40) is accommodated in the container-like member (65) and the intermediate-pressure refrigerant flowing through the index passage (43) is converted into the liquid refrigerant in the container-like member (65). Consists of heat exchange member (66) for heat exchange

A refrigeration apparatus characterized by that.

[4] In claim 1,

In the refrigerant circuit (20), at a position downstream of the intermediate pressure heat exchanger (40) during the cooling operation, there is a low-pressure refrigerant obtained by reducing a part of the high-pressure liquid refrigerant to a low pressure. A refrigeration apparatus comprising a supercooling heat exchanger (60) for cooling the high-pressure liquid refrigerant by heat exchange.

[5] In claim 1,

In the refrigerant circuit (20), a single-stage compression refrigeration cycle is performed,

The compressor (31) is configured such that intermediate-pressure gas refrigerant flows into the compression chamber in the middle of compression.

A refrigeration apparatus characterized by that.

[6] In claim 1,

In the refrigerant circuit (20), a low-stage compressor (33) and a high-stage compressor (34) are connected in series to perform a two-stage compression refrigeration cycle.

The refrigerant circuit (20) is configured to supply intermediate-pressure gas refrigerant to the suction side of the high-stage compressor (34).

A refrigeration apparatus characterized by that.