JP6111663B2 - Air conditioner - Google Patents

Description

    The present invention relates to an air conditioner having a plurality of indoor heat exchangers, and more particularly to an air conditioner configured to perform an operation in which cooling and heating are mixed.

    2. Description of the Related Art Conventionally, an air conditioner that performs a refrigeration cycle in a refrigerant circuit and air-conditions a room is known. As this type of air conditioner, a so-called cooling / heating-free type air conditioner having a plurality of indoor heat exchangers that simultaneously performs cooling and heating is known.

    Patent Document 1 discloses this type of air conditioner. In this air conditioner, an outdoor unit having an outdoor heat exchanger, a switching unit (relay unit) having a gas-liquid separator and a switching circuit, and a plurality of indoor units are connected by pipes to form a refrigerant circuit. Yes. In the air conditioner, by switching the flow path of the switching unit, the cooling only operation, the cooling main operation, the heating only operation, and the heating main operation are performed.

    The cooling main operation is performed under the condition that the entire cooling load is larger than the heating load. In this operation, the high-pressure gas refrigerant compressed by the compressor radiates heat (condenses) by the outdoor heat exchanger and then flows into the gas-liquid separator. In the gas-liquid separator, the gas-liquid two-phase refrigerant is separated into a gas refrigerant and a liquid refrigerant. The gas refrigerant is sent to the indoor heat exchanger on the heating side and radiates heat to the indoor air. As a result, the room is heated. On the other hand, the liquid refrigerant is depressurized by the expansion valve and then sent to the indoor heat exchanger on the cooling side. As a result, the room is cooled. Thus, in the cooling main operation, cooling and heating are performed simultaneously by sending the gas refrigerant and the liquid refrigerant separated by the gas-liquid separator to each indoor heat exchanger.

JP 2010-261713 A

    In the cooling-main operation described above, the optimum total flow rate of the gas refrigerant to be sent to the heating-side indoor heat exchanger and the optimum liquid refrigerant to be sent to the cooling-side indoor heat exchanger according to the ratio of the cooling load to the heating load. The total flow rate will change. Therefore, the flow rate of the gas refrigerant sent to each indoor heat exchanger and the flow rate of the liquid refrigerant are adjusted by adjusting the dryness of the gas-liquid two-phase refrigerant supplied to the gas-liquid separator according to the ratio between the cooling load and the heating load. It is conceivable to optimally control. Specifically, for example, the outdoor heat exchanger is divided into a large number of paths, and the refrigerant flow through each path is switched in multiple stages with an on-off valve or the like to adjust the heat release amount of the refrigerant, and the gas-liquid separator The dryness of the refrigerant to be supplied to can be adjusted in multiple stages. However, in this configuration, the more finely controlled the dryness of the gas-liquid two-phase refrigerant, the more complicated the structure of the outdoor heat exchanger, leading to an increase in cost.

    The present invention has been made in view of the above points, and an object thereof is air conditioning in which the dryness of the refrigerant supplied to the gas-liquid separator can be adjusted with a simple configuration in an operation in which cooling and heating are performed simultaneously. Is to provide a device.

The first invention is a refrigerant circuit (20) in which a compressor (21), an outdoor heat exchanger (22), a gas-liquid separator (41), and a plurality of indoor heat exchangers (71) are connected. In the refrigerant circuit (20), the gas refrigerant separated by the gas-liquid separator (41) is radiated by some indoor heat exchangers (71) and simultaneously separated by the gas-liquid separator (41). The above-mentioned compression is applied to an air conditioner equipped with a refrigerant circuit (20) configured to evaporate the liquefied liquid refrigerant in some indoor heat exchangers (71) and enable a refrigeration cycle to perform heating and cooling simultaneously. A bypass circuit (18 for bypassing a part of the high-pressure gas refrigerant discharged from the machine (21) between the liquid side end of the outdoor heat exchanger (22) and the inflow end of the gas-liquid separator (41) , 31) and adjustment to adjust the ratio of the flow rate of refrigerant flowing out of the bypass circuit (18, 31) to the flow rate of refrigerant flowing out of the outdoor heat exchanger (22) A mechanism ( 35 ) and an opening / closing mechanism (35) for opening and closing the refrigerant flow path, communicating the discharge side of the compressor (21) with the first connecting pipe (11), and the compressor (21 ) And the second communication pipe (12), the discharge side of the compressor (21) and the second communication pipe (12) are communicated, and the compressor A switching circuit (25) for switching between the suction side of (21) and the first communication pipe (11), and the adjustment mechanism (35) includes the switching circuit (25). The opening / closing mechanism is also used .

    In the first invention, the refrigerant compressed by the compressor (21) radiates heat in the outdoor heat exchanger (22) and then flows into the gas-liquid separator (41). In the gas-liquid separator (41), the refrigerant is separated into a gas refrigerant and a liquid refrigerant. The gas refrigerant is supplied to some of the plurality of indoor heat exchangers (71) and radiates heat to the room air. As a result, the room is heated. The liquid refrigerant is supplied to a part of the plurality of indoor heat exchangers (71) and absorbs heat from the indoor air to evaporate. As a result, the room is cooled.

In such operation, the dryness of the refrigerant supplied to the gas-liquid separator (41) is adjusted by the adjusting mechanism ( 35 ). That is, the refrigerant circuit (20) is provided with a bypass circuit (18, 31) in which a part of the high-pressure gas refrigerant discharged from the compressor (21) bypasses the outdoor heat exchanger (22). For this reason, in the refrigerant circuit (20), the refrigerant radiated by the outdoor heat exchanger (22) and the gas refrigerant passed through the bypass circuit (18, 31) are mixed on the inflow side of the gas-liquid separator (41). To do. The adjusting mechanism ( 35 ) adjusts the ratio of the flow rate of the refrigerant flowing out of the bypass circuit (18, 31) to the flow rate of the refrigerant flowing out of the outdoor heat exchanger (22). As a result, the dryness of the refrigerant supplied to the gas-liquid separator (41) can be adjusted.

In a second aspect based on the first aspect, the adjusting mechanism ( 35 ) increases the ratio as the ratio of the overall heating load to the overall cooling load of the plurality of indoor heat exchangers (71) increases. It is comprised so that it may do.

    In the second invention, as the ratio of the heating load to the entire air conditioning load of the air conditioner increases, the flow rate of the refrigerant in the bypass circuit (18, 31) with respect to the flow rate of the refrigerant radiated by the outdoor heat exchanger (22) is reduced. The ratio increases. As a result, the dryness of the refrigerant after mixing on the inflow side of the gas-liquid separator (41) increases. Therefore, in the gas-liquid separator (41), the ratio of the gas refrigerant to the liquid refrigerant is increased, and the gas refrigerant commensurate with the heating load can be supplied to the indoor heat exchanger (71).

    According to a third invention, in the first or second invention, the refrigerant circuit (20) is configured such that the refrigerant after radiating heat to the outdoor air by the outdoor heat exchanger (22) becomes a liquid refrigerant. It is characterized by that.

    In 3rd invention, a refrigerating cycle is performed so that the refrigerant | coolant after thermally radiating with an outdoor heat exchanger (22) turns into a liquid refrigerant. That is, on the inflow side of the gas-liquid separator (41), the gas refrigerant flowing out of the bypass circuit (18, 31) and the liquid refrigerant flowing out of the outdoor heat exchanger (22) are mixed. In this way, compared with the case where the refrigerant flowing out of the outdoor heat exchanger (22) is in a gas-liquid two-phase state, it is possible to easily estimate the dryness of the refrigerant after mixing. Therefore, the dryness of the refrigerant supplied to the gas-liquid separator (41) can be accurately adjusted.

According to a fourth invention, in any one of the first to third inventions, an outdoor unit (2) having an outdoor circuit (20a) to which the compressor (21) and the outdoor heat exchanger (22) are connected; The gas-liquid separation unit (4, 6) having the relay circuit (20c, 20e) to which the gas-liquid separator (41) is connected is connected to the outdoor circuit (20a) and the relay circuit (20c, 20e). And two connecting pipes (11, 12).

    In the fourth invention, the outdoor unit (2) and the gas-liquid separation unit (4, 6) are connected by the two connecting pipes (11, 12).

    According to a fifth invention, in the fourth invention, the relay circuit (20c, 20e) is provided with a switching mechanism (63, 64, 20e) for switching the flow of liquid refrigerant and gas refrigerant in the indoor heat exchanger (71). 83, 84, 85) are connected.

    In the fifth invention, the switching mechanism (63, 64, 83, 84, 85) and the gas-liquid separator (41) are connected to the relay circuit (20c, 20e) of the gas-liquid separation unit (4, 6).

    A sixth invention is characterized in that, in any one of the first to fifth inventions, the refrigerant in the refrigerant circuit (20) is difluoromethane.

    In the sixth invention, a refrigeration cycle using difluoromethane is performed in the refrigerant circuit (20).

According to the present invention, the ratio of the flow rate of the refrigerant radiated by the outdoor heat exchanger (22) and the flow rate of the refrigerant that has flowed out of the bypass circuit (18, 31) is adjusted by the adjustment mechanism ( 35 ). The dryness of the refrigerant supplied to the separator (41) can be adjusted. As a result, the ratio of the gas refrigerant to the liquid refrigerant separated by the gas-liquid separator (41) can be easily changed, and the heating-side indoor heat exchanger (71) and the cooling-side indoor heat exchanger (71) can be changed. An optimal flow rate of refrigerant can be supplied. In the present invention, only the bypass circuit (18, 31) and the adjusting mechanism ( 35 ) are provided, and the structure of the outdoor heat exchanger (22) is not complicated. For this reason, simplification of an air conditioning apparatus and reduction of cost can be aimed at. Furthermore, in the present invention, the degree of dryness of the refrigerant supplied to the gas-liquid separator (41) can be finely adjusted by controlling the flow rate of the refrigerant in the bypass circuit (18, 31).

    In the second aspect of the invention, it is possible to supply gas refrigerant and liquid refrigerant having optimum flow rates in accordance with the ratio between the cooling load and the heating load. In the third invention, the dryness of the refrigerant supplied to the gas-liquid separator (41) can be accurately adjusted.

    In the fourth aspect of the invention, the outdoor unit (2) and the gas-liquid separation unit (4, 6) are connected by two connecting pipes (11, 12). Can be simplified and construction is also easy. In addition, by attaching the gas-liquid separation unit according to the present invention to an existing building multi-type air conditioner having two connecting pipes, it is possible to impart a cooling / heating-free function to the air conditioner. it can. In the sixth aspect of the invention, in the air conditioner using difluoromethane, it is possible to supply an optimal flow rate of refrigerant to the heating-side indoor heat exchanger (71) and the cooling-side indoor heat exchanger (71).

FIG. 1 is a piping diagram of an air conditioner according to the first embodiment. FIG. 2 is a piping system diagram of the air-conditioning apparatus according to Embodiment 1, and shows the refrigerant flow in the first heating main operation (all heating operation). FIG. 3 is a piping system diagram of the air-conditioning apparatus according to Embodiment 1, and shows the refrigerant flow in the first heating main operation (with cooling load). FIG. 4 is a piping system diagram of the air-conditioning apparatus according to Embodiment 1, and shows the refrigerant flow in the second heating main operation. FIG. 5 is a piping system diagram of the air-conditioning apparatus according to Embodiment 1, and represents the flow of the refrigerant in the first cooling main operation. FIG. 6 is a piping system diagram of the air-conditioning apparatus according to Embodiment 1, and shows the refrigerant flow in the second cooling main operation (all cooling operation). FIG. 7 is a piping diagram of an air conditioner according to a modification of the first embodiment. FIG. 8 is a piping diagram of an air conditioner according to Reference Example 1 . FIG. 9 is a piping system diagram of the air-conditioning apparatus according to Reference Example 1 , and shows the refrigerant flow in the first heating main operation (all heating operation). FIG. 10 is a piping system diagram of the air-conditioning apparatus according to Reference Example 1 , and shows the flow of refrigerant in the second heating main operation. FIG. 11 is a piping system diagram of the air-conditioning apparatus according to Reference Example 1 , and shows the flow of the refrigerant in the first cooling main operation. FIG. 12 is a piping system diagram of the air-conditioning apparatus according to Reference Example 1 , and shows the refrigerant flow in the second cooling main operation (all cooling operation). FIG. 13 is a piping diagram of an air conditioner according to Reference Example 2 . FIG. 14 is a piping system diagram of the air-conditioning apparatus according to Reference Example 2 , and shows the refrigerant flow in the first heating main operation (all heating operation). FIG. 15 is a piping system diagram of the air-conditioning apparatus according to Reference Example 2 , and shows the flow of refrigerant in the second heating main operation. FIG. 16 is a piping system diagram of the air-conditioning apparatus according to Reference Example 2 , and shows the flow of the refrigerant in the first cooling main operation. FIG. 17 is a piping system diagram of the air-conditioning apparatus according to Reference Example 2 , and shows the refrigerant flow in the second cooling main operation (all cooling operation).

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

Embodiment 1 of the Invention
Embodiment 1 relates to a so-called cooling / heating-free type air conditioner that includes a plurality of indoor units connected in parallel to an outdoor unit and is configured to be capable of operation in which cooling and heating are mixed. This air conditioner has a configuration suitable for renewing an existing indoor multi-type air conditioner that is switched without mixing cooling and heating to a cooling / heating free type air conditioner. In the following description, it is assumed that the refrigerant circuit of the apparatus before the update is filled with R410A or R22 as the old refrigerant, and the refrigerant circuit of the apparatus after the update is filled with R32 (difluoromethane) as the new refrigerant.

    As shown in FIG. 1, this air conditioner (1) includes an outdoor unit (2), a plurality (three in the figure) indoor units (3), and a gas-liquid separation unit (4 ) And the same number of operation switching units (5) as the indoor units (3). The outdoor unit (2) has an outdoor circuit (20a), each indoor unit (3) has an indoor circuit (20b), and the gas-liquid separation unit (4) has a first relay circuit (20c). A second relay circuit (20d) is connected to each unit (5). The outdoor circuit (20a) and the first relay circuit (20c) are connected to each other via two outdoor connection pipes (11, 12). Each second relay circuit (20d) is connected in parallel to the first relay circuit (20c) via three intermediate connection pipes (15, 16, 17). Each indoor circuit (20b) is connected to each second relay circuit (20d) via two indoor communication pipes (13, 14). A refrigerant circuit (20) capable of a cooling / heating free type refrigeration cycle is configured by connecting the outdoor path (20a, the first relay circuit (20c), the second relay circuit (20d), and the indoor circuit (20b). Has been.

    The outdoor communication pipe (11, 12) is composed of an outdoor first communication pipe (11) and an outdoor second communication pipe (12). The indoor communication pipe (13, 14) is composed of an indoor first communication pipe (13) and an indoor second communication pipe (14). The intermediate part connecting pipe (15, 16, 17) is composed of an intermediate part first connecting pipe (15), an intermediate part second connecting pipe (16), and an intermediate part third connecting pipe (17). The outside connection pipes (11, 12), the indoor connection pipes (13, 14), and the intermediate connection pipes (15, 16, 17) have the same inner diameter as the first connection pipes (11, 13, 15). Each of the second connecting pipes (12, 14, 16) has the same inner diameter and is larger than the inner diameter of each of the first connecting pipes (11, 13, 15). The inner diameter of the intermediate third communication pipe (17) is the same as that of the intermediate second communication pipe (16).

    The outdoor unit (2) includes a compressor (21) that compresses refrigerant, an outdoor heat exchanger (heat source side heat exchanger) (22) that exchanges heat between the refrigerant and outdoor air, and an outdoor first communication pipe (11) and an outdoor switching mechanism (23) for switching the flow direction of the refrigerant in the outdoor second communication pipe (12). The outdoor unit (2) includes a first outdoor communication pipe port (2a) to which the outdoor first communication pipe (11) is connected and a second outdoor communication pipe to which the outdoor second communication pipe (12) is connected. Has a port (2b). The outdoor switching mechanism (23) includes a three-way valve (24) and a switching circuit (piping switching unit) (25) configured by combining four motor operated valves (35, 36, 37, 38).

    The discharge pipe (26) of the compressor (21) is connected to the first port (24a) of the three-way valve (24), and the second port (24b) of the three-way valve (24) is connected to the outdoor heat exchanger (22). Connected to the gas side end, the third port (24c) of the three-way valve (24) is connected to the suction side pipe (27) of the compressor (21). The liquid side end of the outdoor heat exchanger (22) is connected to the switching circuit (25). The three-way valve (24) is connected to the discharge side pipe (26) so that one of the discharge side pipe (26) and the suction side pipe (27) of the compressor (21) communicates with the gas side end of the outdoor heat exchanger (22). 26) A switching valve that switches the communication state between the suction side pipe (27). That is, the three-way valve (24) includes a first state (state indicated by a solid line in FIG. 1) in which the second port (24b) and the third port (24c) communicate with each other, a second port (24b), and the first port. (24a) is configured to be switchable to a second state (a state indicated by a broken line in FIG. 1) in communication.

    The switching circuit (25) has four passages (31, 32, 33, 34) and four connection points (seconds) connecting the four passages (31, 32, 33, 34) to each other at their respective ends. 1 connection point (P11), 2nd connection point (P12), 3rd connection point (P13) and 4th connection point (P14)), and each of the passages (31, 32, 33, 34) provided above It has four motorized valves (open / close mechanisms) (35, 36, 37, 38). As the four motor-operated valves, the outdoor first motor-operated valve (35) is provided in the first passage (31), the outdoor second motor-operated valve (36) is provided in the second passage (32), and the third passage (33) is provided. An outdoor third electric valve (37) is provided, and an outdoor fourth electric valve (38) is provided in the fourth passage (34). Specifically, the switching circuit (25) has the first connection point (P11) and the second connection point (P12) connected by the first passage (31), and the second connection point (P12) and the third connection. The point (P13) is connected by the second passage (32), the third connection point (P13) and the fourth connection point (P14) are connected by the third passage (33), and the fourth connection point (P14). And the first connection point (P11) are connected by the fourth passage (34).

    The first connection point (P11) of the switching circuit (25) is connected to the discharge side pipe (26) of the compressor (21) via the bypass pipe (18), and the second connection point (P12) is connected to the outdoor side. It is connected to one connection pipe (11). The third connection point (P13) is connected to the liquid side end of the outdoor heat exchanger (22), and the fourth connection point (P14) is the intake of the outdoor second communication pipe (12) and the compressor (21). It is connected to the side pipe (27) via each branch pipe (28a, 28b). The branch pipe (28b) between the fourth connection point (P14) and the suction side pipe (27) of the compressor (21) is provided with a solenoid valve (open / close valve) (29). The first passage (31) and the bypass pipe (28) constitute a bypass circuit in which a part of the high-pressure gas refrigerant bypasses the outdoor heat exchanger (22) in the first cooling main operation described in detail later.

    The gas-liquid separation unit (4) includes a gas-liquid separator (41), liquid refrigerant (or two-phase refrigerant) and gas in the intermediate connecting pipe (15, 16, 17) and outdoor connecting pipe (11, 12). A refrigerant flow switching circuit (42) for switching the flow of the refrigerant. The gas-liquid separation unit (4) includes a first outdoor communication pipe port (4a) to which the outdoor first communication pipe (11) is connected and a second outdoor communication pipe (12) to which the second outdoor communication pipe (12) is connected. It has an outdoor communication piping port (4b). The gas-liquid separation unit (4) includes a first intermediate connection pipe port (4c) to which the intermediate first communication pipe (15) is connected, and a second intermediate connection pipe to which the intermediate second communication pipe (16) is connected. It has a port (4d) and a third intermediate communication pipe port (4e) to which the intermediate third communication pipe (17) is connected.

    The refrigerant flow switching circuit (42) has four passages (43a, 43b, 43c, 43d) and four connections in which the four passages (43a, 43b, 43c, 43d) are connected to each other at their respective ends. Point (first connection point (P21), second connection point (P22), third connection point (P23) and fourth connection point (P24)) and each passage (43a, 43b, 43c, 43d) This is a circuit having four check valves (CV1, CV2, CV3, CV4).

    The first connection point (P21) of the refrigerant flow switching circuit (42) is connected to the second intermediate connection pipe port (4d) via the first connection pipe (51). The second connection point (P22) of the refrigerant flow switching circuit (42) is connected to the first outdoor communication pipe port (4a) via the second connection pipe (52). The third connection point (P23) of the refrigerant flow switching circuit (42) is connected to the refrigerant inlet (41a) of the gas-liquid separator (41) via the third connection pipe (53). The fourth connection point (P24) of the refrigerant flow switching circuit (42) is connected to the second outdoor communication pipe port (4b) via the fourth connection pipe (54).

    The gas refrigerant outlet (41b) of the gas-liquid separator (41) is connected to the third intermediate connection pipe port (4e) via the fifth connection pipe (55). The liquid refrigerant outlet (41c) of the gas-liquid separator (41) is connected to the first intermediate connection pipe port (4c) via the sixth connection pipe (56) having the intermediate first motor-operated valve (58). Yes. A seventh connection pipe (57) is connected to the sixth connection pipe (56) between the intermediate first motor-operated valve (58) and the first intermediate connection pipe port (4c). The seventh connection pipe (57) is a branch pipe having a first branch pipe (57a) and a second branch pipe (57b), and the first branch pipe (57a) is connected to the first connection pipe (51). The branch pipe (57b) is connected to the second connection pipe (52). The first branch pipe (57a) and the second branch pipe (57b) are provided with an intermediate second electric valve (59a) and an intermediate third electric valve (59b), respectively.

    In the refrigerant flow switching circuit (42), as the above four check valves, the refrigerant flow from the first connection point (P21) to the second connection point (P22) is allowed and the refrigerant flow in the reverse direction is allowed. The first check valve (CV1) to be prohibited and the second check valve that allows the refrigerant flow from the second connection point (P22) to the third connection point (P23) and prohibits the refrigerant flow in the reverse direction ( CV2), a third check valve (CV3) that permits refrigerant flow from the first connection point (P21) to the fourth connection point (P24) and prohibits refrigerant flow in the reverse direction, and a fourth connection point A fourth check valve (CV4) is provided that allows the refrigerant flow from (P24) to the third connection point (P23) and prohibits the refrigerant flow in the reverse direction.

    An intermediate fourth motor-operated valve (59c) is provided between the second connection point (P22) and the second check valve (CV2) in the passage (43b) of the refrigerant flow switching circuit (42). . The intermediate fourth motor-operated valve (59c) is a valve that is closed during a second cooling main operation (all cooling operation) to be described later to prevent the refrigerant from flowing into the gas-liquid separator (41).

    The operation switching unit (5) is connected to each indoor unit (3) by two indoor communication pipes (13, 14). Each operation switching unit (5) has a liquid refrigerant between the intermediate connecting pipe (15, 16, 17) and the indoor connecting pipe (13, 14) corresponding to the cooling / heating switching of each indoor unit (3). A flow path switching circuit (65) for switching the flow path of the gas refrigerant is provided. Each operation switching unit (5) has a first indoor communication pipe port (5a) to which the indoor first communication pipe (13) is connected and a second indoor communication pipe (14) to which the second indoor communication pipe (14) is connected. The indoor communication piping port (5b), the first intermediate communication piping port (5c) to which the intermediate first communication piping (15) is connected, and the second intermediate communication to which the intermediate second communication piping (16) is connected The piping port (5d) has a third intermediate connecting piping port (5e) to which the intermediate third connecting piping (17) is connected.

    The operation switching unit (5) is connected to the first communication pipe (61) connecting the first indoor communication pipe port (5a) and the first intermediate communication pipe port (5c) and the second indoor communication pipe port (5b). The second intermediate connecting pipe port (5d) and the third intermediate connecting pipe port (5e) are connected in parallel to each other. The second communication pipe (62) includes a first branch pipe (62a) connected to the second intermediate connection pipe port (5d) and a second branch pipe (62b) connected to the second intermediate connection pipe port (5d). ). The first branch pipe (62a) and the second branch pipe (62b) are provided with a first switching valve (63) and a second switching valve (64), respectively. The first switching valve (63) and the second switching valve (64) constitute the flow path switching circuit (65).

    The indoor unit (3) has an indoor heat exchanger (71) and an indoor expansion valve (72). The indoor unit (3) has a first indoor communication piping port (3a) and a second indoor communication piping port (3b), and the first indoor communication piping port (3a) and the second indoor communication piping port (3b). Between them, the indoor expansion valve (72) and the indoor heat exchanger (71) are connected in order.

    The first intermediate connection pipe port (5c) of the operation switching unit (5) and the first intermediate connection pipe port (4c) of the gas-liquid separation unit (4) are connected by the intermediate first communication pipe (15), and the operation is switched. The second intermediate connection piping port (5d) of the unit (5) and the second intermediate connection piping port (4d) of the gas-liquid separation unit (4) are connected by the intermediate second connection piping (16). The third intermediate connecting piping port (5e) of 5) and the third intermediate connecting piping port (4e) of the gas-liquid separation unit (4) are connected by the intermediate third connecting piping (17). The middle first connecting pipe (15) forms part of the liquid side connecting pipe, and the middle second connecting pipe (16) and the middle third connecting pipe (17) are part of the gas side connecting pipe. Is configured.

    In addition, the first indoor communication piping port (5a) of the operation switching unit (5) and the first indoor communication piping port (3a) of the indoor unit (3) are connected by the indoor first communication piping (13) to switch the operation. The second indoor communication piping port (5b) of the unit (5) and the second indoor communication piping port (3b) of the indoor unit (3) are connected by the indoor second communication piping (14). The indoor first communication pipe (13) constitutes a part of the liquid side communication pipe, and the indoor second communication pipe (14) constitutes a part of the gas side communication pipe.

    The air conditioner (1) is provided with a controller (100). A controller (100) controls each component apparatus of a refrigerant circuit (20) with the switching of each operation | movement mentioned later for details. The controller (100) is provided with a bypass valve control unit (101). In the first cooling main operation, the bypass valve control unit (101) is configured to control the outdoor first in accordance with the ratio of the overall heating load to the overall cooling load of the air conditioner (1) (hereinafter also referred to as the heating ratio). Adjust the opening of the motorized valve (bypass valve) (35). Specifically, the bypass valve control unit (101) is configured to increase the opening degree of the outdoor first electric valve (35) as the heating ratio increases. The outdoor first electric valve (35) and the bypass valve control unit (101) flow out of the bypass circuit (bypass pipe (18) and first passage (31)) for the flow rate of the refrigerant flowing out of the outdoor heat exchanger (22). An adjustment mechanism for adjusting the ratio of the flow rate of the refrigerant is configured.

-Driving action-
Next, the operation of the air conditioner (1) of this embodiment will be described. In the air conditioner (1), the first heating main operation, the second heating main operation, the first cooling main operation, and the second cooling main operation are performed by switching. In the following description, in order from the top to the bottom of FIGS. 1 to 6, the indoor unit (3) is replaced with a first indoor unit (3A), a second indoor unit (3B), and a third indoor unit as necessary. The operation switching unit (5) is referred to as a first operation switching unit (5A), a second operation switching unit (5B), and a third operation switching unit (5C) as necessary.

<First heating main operation>
The first heating main operation is an operation performed in a first load region where the cooling load is as small as about 20% from zero among all the air conditioning loads. As an example of the first heating main operation, the all heating operation will be described with reference to FIG.

    In the all-heating operation, heating is performed in all indoor units (3A, 3B, 3C). In the all-heating outdoor unit (2), the three-way valve (24) is set to the first state, the outdoor second motor-operated valve (36) and the outdoor fourth motor-operated valve (38) are opened, and the outdoor first motor-operated valve (35), the outdoor third electric valve (37), the intermediate fourth electric valve (59c), and the electromagnetic valve (29) are closed. In the gas-liquid separation unit (4), the intermediate third electric valve (59b) is opened, and the intermediate first electric valve (58) and the intermediate second electric valve (59a) are closed. In the operation switching unit (5), the second switching valve (64) is opened and the first switching valve (63) is closed in all the operation switching units (5A, 5B, 5C). In the indoor unit (3), the indoor expansion valve (72) is opened in all the indoor units (3A, 3B, 3C).

    When the compressor (21) is started, the discharged high-pressure gas refrigerant flows into the gas-liquid separation unit (4) from the outdoor second communication pipe (12) through the switching circuit (25). The high-pressure gas refrigerant flows into the operation switching unit (5) from the intermediate third communication pipe (17) through the gas-liquid separator (41), and further passes through the second indoor communication pipe (14). It flows into the indoor unit (3). The refrigerant condenses in the indoor heat exchanger (71) and heats indoor air, and then flows out from each indoor unit (3). The indoor first communication pipe (13), each operation switching unit (5), and the intermediate part It flows into the gas-liquid separation unit (4) through the first connection pipe (15). The liquid refrigerant passes through the intermediate third motor-operated valve (59b), the refrigerant flow path switching circuit (42), and the outdoor first communication pipe (11) and returns to the outdoor unit (2). The liquid refrigerant flowing into the outdoor unit (2) expands in the outdoor second motor-operated valve (36) of the switching circuit (25), evaporates in the outdoor heat exchanger (22), and is sucked into the compressor (21). .

    As the refrigerant circulates in the refrigerant circuit (20) as described above, heating is performed in all the indoor units (3).

    In the above example, the intermediate third motor-operated valve (59b) is opened and the refrigerant is expanded by the outdoor second motor-operated valve (36) of the switching circuit (25). The configuration may be such that the refrigerant is expanded in 59b) and the outdoor second motor-operated valve (36) is opened, or both motor-operated valves (59b, 36) may be used to expand the refrigerant.

    In FIG. 2, the heating only operation has been described as the first heating main operation. However, the first heating main operation includes an operation in which cooling is performed by a part of the plurality of indoor units (3) as shown in FIG. 3. It is.

    At this time, in the outdoor unit (2), the three-way valve (24) is set to the first position, the switching circuit (25) is set to the first position, and the electromagnetic valve (29) is closed. The outdoor second motor operated valve (36) is opened. In the gas-liquid separation unit (4), the intermediate third motor-operated valve (59b) is adjusted to a predetermined opening, and the intermediate first motor-operated valve (58), the intermediate second motor-operated valve (59a), and the intermediate fourth motor-operated valve (59c) ) Will be closed. In the first operation switching unit (5A) and the second operation switching unit (5B) that perform heating, the second switching valve (64) is opened, the first switching valve (63) is closed, and the third operation that performs cooling is performed. In the switching unit (5C), the first switching valve (63) is opened and the second switching valve (64) is closed.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant flows into the gas-liquid separation unit (4) from the outdoor second connection pipe (12) through the switching circuit (25). The high-pressure gas refrigerant flows into the first and second operation switching units (5A, 5B) from the intermediate third communication pipe (17) through the gas-liquid separator (41), and further to the indoor second communication pipe ( 14) flows into the first and second indoor units (3A, 3B). The refrigerant condenses in the indoor heat exchanger (71) and heats the indoor air, and then flows out of the first and second indoor units (3A, 3B), and the indoor first communication pipe (13), first, first The refrigerant passes through the 2 operation switching unit (5A, 5B) and is divided into the refrigerant flowing into the gas-liquid separation unit (4) and the refrigerant flowing into the third operation switching unit (5C) through the intermediate first connection pipe (15). .

  From the third operation switching unit (5C), the refrigerant flows into the third indoor unit (3C) through the indoor first communication pipe (13) and evaporates in the indoor heat exchanger (71). Return from the connection pipe (14) to the gas-liquid separation unit (4) through the intermediate second connection pipe (16).

    The liquid refrigerant flowing into the gas-liquid separation unit (4) from the intermediate first communication pipe (15) is depressurized by the intermediate third motor operated valve (59b) and becomes a low-pressure two-phase refrigerant in the second connection pipe (52). Flow into. The gas refrigerant that has flowed into the gas-liquid separation unit (4) from the intermediate second connection pipe (16) includes the first connection pipe (51), the first connection point (P21), the passage (43a), and the second connection point. It passes through (P22) and merges with the low-pressure two-phase refrigerant of the second connection pipe (52). The merged refrigerant is low-pressure two-phase.

    This low-pressure two-phase refrigerant returns to the outdoor unit (2) through the outdoor first communication pipe (11), passes through the outdoor second motor-operated valve (36) of the switching circuit (25), and then enters the outdoor heat exchanger ( It evaporates in 22) and is sucked into the compressor (21).

    As the refrigerant circulates in the refrigerant circuit (20) as described above, heating is performed in most of the indoor units (3), and cooling is performed in part.

<Second heating main operation>
The second heating main operation is an operation performed in the second load region where the cooling load is about 20% to 50% of the total air conditioning load. Here, as shown in FIG. 4, an example will be described in which heating is performed by the first and second indoor units (3A, 3B) and cooling is performed by the third indoor unit (3C).

    The second heating main operation shown in FIG. 4 is an operation performed when the heating load is larger than the cooling load among the entire air conditioning load of the air conditioner (1). Here, an example will be described in which heating is performed by the first and second indoor units (3A, 3B) and cooling is performed by the third indoor unit (3C). In the outdoor unit (2), the three-way valve (24) is set to the first state, and the outdoor first motor-operated valve (35), the outdoor third motor-operated valve (37), and the intermediate fourth motor-operated valve (59c) are opened. The outdoor second motor-operated valve (36), the outdoor fourth motor-operated valve (38), and the electromagnetic valve (29) are closed. In the gas-liquid separation unit (4), the intermediate second electric valve (59a) is opened, and the intermediate first electric valve (58) and the intermediate third electric valve (59b) are closed. In the first and second operation switching units (5A, 5B), the second switching valve (64) is opened and the first switching valve (63) is closed. In the third operation switching unit (5C), the first switching valve (63) is opened and the second switching valve (64) is closed. In the first and second indoor units (3A, 3B), the indoor expansion valve (72) is opened. In the third indoor unit (3C), the opening degree of the indoor expansion valve (72) is adjusted.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant flows into the gas-liquid separation unit (4) from the outdoor first communication pipe (11) through the switching circuit (25). The high-pressure gas refrigerant flows into the gas-liquid separator (41) through the refrigerant flow switching circuit (42). The high-pressure gas refrigerant flows out from the gas refrigerant outlet (41b) of the gas-liquid separator (41), passes through the intermediate third communication pipe (17), and flows into each operation switching unit (5).

    As described above, in the first and second operation switching units (5A, 5B), the second switching valve (64) is opened and the first switching valve (63) is closed. In the third operation switching unit (5C), the first switching valve (63) is opened and the second switching valve (64) is closed. Accordingly, the refrigerant flows from the first and second operation switching units (5A, 5B) through the indoor second communication pipe (14) to the first and second indoor units (3A, 3B). In the first and second indoor units (3A, 3B), the refrigerant condenses and dissipates heat, and the indoor air is heated. The condensed liquid refrigerant returns to the first and second operation switching units (5A, 5B), a part thereof goes to the third operation switching unit (5C), and the other part goes to the gas-liquid separation unit (4).

    The liquid refrigerant that has flowed into the third operation switching unit (5C) further flows into the third indoor unit (3C) through the indoor first communication pipe (13), and is reduced in pressure by the indoor expansion valve (72). It becomes a two-phase refrigerant. This low-pressure two-phase refrigerant evaporates into a gas refrigerant in the indoor heat exchanger (71), and passes from the third indoor unit (3C) through the indoor first communication pipe (13) to the third operation switching unit (5C). Flow into. The gas refrigerant that has flowed into the third operation switching unit (5C) flows from the first branch pipe (62a) into the gas-liquid separation unit (4) through the intermediate second communication pipe (16).

    In the gas-liquid separation unit (4), the liquid refrigerant flowing in from the first and second operation switching units (5A, 5B) is depressurized by the intermediate second electric valve (59a) to become a low-pressure two-phase refrigerant, and the third operation switching. Combines with the low-pressure gas refrigerant flowing in from the unit (5C). The refrigerant in which the low-pressure two-phase refrigerant and the low-pressure gas refrigerant are mixed is a low-pressure two-phase refrigerant, and this low-pressure two-phase refrigerant passes through the second outdoor connection pipe (12) from the refrigerant flow switching circuit (42) to the outdoor unit. Return to (2). The low-pressure two-phase refrigerant that has returned to the outdoor unit (2) flows into the outdoor heat exchanger (22) through the switching circuit (25), evaporates by exchanging heat with the outdoor air. The low-pressure gas refrigerant evaporated in the outdoor heat exchanger (22) is sucked into the compressor (21) through the three-way valve (24).

    As the refrigerant circulates in the refrigerant circuit (20) as described above, a refrigeration cycle is performed in which the first and second indoor units (3A, 3B) heat and the third indoor unit (3C) cools. Is called.

<First cooling operation>
Next, as the first cooling main operation, a state in which heating is performed by the first indoor unit (3A) and cooling is performed by the second and third indoor units (3B, 3C) will be described with reference to FIG. In the outdoor unit (2), the three-way valve (24) is set to the second state, the outdoor first electric valve (35), the outdoor second electric valve (36), and the electromagnetic valve (29) are opened, The three motor-operated valves (37) and the outdoor fourth motor-operated valve (38) are closed. In the gas-liquid separation unit (4), the intermediate first electric valve (58) is opened, and the intermediate second electric valve (59a) and the intermediate third electric valve (59b) are closed. In the first operation switching unit (5A), the second switching valve (64) is opened and the first switching valve (63) is closed. In the second and third operation switching units (5), the first switching valve (63) is opened and the second switching valve (64) is closed. In the first indoor unit (3A), the indoor expansion valve (72) is opened. In the second and third indoor units (3B, 3C), the opening degree of the indoor expansion valve (72) is adjusted.

    When the compressor (21) is started, a part of the discharged high-pressure gas refrigerant flows into the outdoor heat exchanger (22) through the three-way valve (24) and is condensed in the outdoor heat exchanger (22). It becomes liquid refrigerant and flows into the switching circuit (25). The other part of the high-pressure gas refrigerant discharged from the compressor (21) flows into the switching circuit (25) as the gas refrigerant. Then, the liquid refrigerant and the gas refrigerant are mixed in the switching circuit (25) to become a high-pressure two-phase refrigerant, and flow into the gas-liquid separation unit (4) through the outdoor first communication pipe (11).

    The high-pressure two-phase refrigerant that has flowed into the gas-liquid separation unit (4) flows into the gas-liquid separator (41) through the refrigerant flow switching circuit (42), and is separated into liquid refrigerant and gas refrigerant. The gas refrigerant flows from the intermediate third communication pipe (17) into the first operation switching unit (5A), and further flows through the indoor second communication pipe (14) into the first indoor unit (3A). In the first indoor unit (3A), the refrigerant is condensed and dissipated in the indoor heat exchanger (71), and the indoor air is heated. The liquid refrigerant condensed in the indoor heat exchanger (71) of the first indoor unit (3A) merges with the liquid refrigerant flowing out of the gas-liquid separator (41), and the second and third operation switching units (5B, 5C). Head to).

    The liquid refrigerant that has flowed into the second and third operation switching units (5B, 5C) flows into the second and third indoor units (3B, 3C) through the indoor first communication pipe (13) and is expanded indoors. After being depressurized by the valve (72), it is evaporated by the indoor heat exchanger (71). At this time, the room air is cooled. The gas refrigerant that has passed through the indoor heat exchanger (71) passes through the indoor second communication pipe (14), the second and third operation switching units (5B, 5C), and the intermediate second communication pipe (16). It flows into the gas-liquid separation unit (4). This refrigerant returns to the outdoor unit (2) through the refrigerant flow switching circuit (42) of the gas-liquid separation unit (4) and the outdoor second connection pipe (12), and is compressed through the solenoid valve (29). Inhaled into the machine (21).

    As the refrigerant circulates in the refrigerant circuit (20) as described above, a refrigeration cycle is performed in which the first indoor unit (3A) heats and the second and third indoor units (3B, 3C) cool. Is called.

<Second cooling-dominated operation>
Next, the second cooling main operation that is a cooling only operation will be described with reference to FIG. In the outdoor unit (2) for the cooling only operation, the three-way valve (24) is set to the second state, the outdoor second electric valve (36) and the electromagnetic valve (29) are opened, and the outdoor first electric valve (35) The outdoor third electric valve (37) and the outdoor fourth electric valve (38) are closed. In the gas-liquid separation unit (4), the intermediate third motor-operated valve (59b) is opened, and the intermediate first motor-operated valve (58), the intermediate second motor-operated valve (59a), and the intermediate fourth motor-operated valve (59c) are closed. Is done. In the operation switching unit (5), the first switching valve (63) is opened and the second switching valve (64) is closed in all the operation switching units (5). In the indoor unit (3), the opening degree of the indoor expansion valve (72) is adjusted in all the indoor units (3A, 3B, 3C).

    When the compressor (21) is started, the discharged high-pressure gas refrigerant flows into the outdoor heat exchanger (22) through the three-way valve (24) and is condensed by the outdoor heat exchanger (22). It becomes. The high-pressure liquid refrigerant passes through the switching circuit (25), and further flows into the gas-liquid separation unit (4) through the outdoor first communication pipe (11).

    The high-pressure liquid refrigerant flowing into the gas-liquid separation unit (4) does not pass through the refrigerant flow switching circuit (42) and the gas-liquid separator (41), passes through the intermediate third motor-operated valve (59b), It flows out from one connection pipe (15) and flows into each operation switching unit (5).

    The high-pressure liquid refrigerant passes through each operation switching unit (5) and flows into each indoor unit (3) from the indoor first communication pipe (13). The high-pressure liquid refrigerant is depressurized by the indoor expansion valve (72) of each indoor unit (3) and is evaporated by the indoor heat exchanger (71). The gas refrigerant evaporated in the indoor heat exchanger (71) passes through the indoor second communication pipe (14), the first branch pipe (62a) of the operation switching unit (5), and the intermediate second communication pipe (16). Flow into the gas-liquid separation unit (4). This low-pressure gas refrigerant returns to the outdoor unit (2) through the refrigerant flow switching circuit (42) of the gas-liquid separation unit (4) and the outdoor second communication pipe (12). The low-pressure gas refrigerant that has returned to the outdoor unit (2) passes through the solenoid valve (29) and is sucked into the compressor (21).

    As the refrigerant circulates through the refrigerant circuit (20) as described above, a refrigeration cycle for cooling the entire indoor unit (3) is performed.

<Bypass operation>
In the first cooling main operation described above, a bypass operation is performed to adjust the dryness of the gas-liquid two-phase refrigerant supplied to the gas-liquid separator (41). Specifically, in the first cooling main operation, the ratio of the entire heating load to the entire cooling load (heating ratio) is obtained. The heating ratio is calculated by the controller (100) based on the number of indoor units (3) in which cooling operation or heating operation is performed, the cooling load or heating load of each indoor unit (3A, 3B, 3C), and the like. In the first cooling main operation, the bypass valve control unit (101) appropriately adjusts the opening degree of the outdoor first electric valve (35) in accordance with the heating ratio thus obtained.

    More specifically, in the first cooling main operation, a part of the high-pressure gas refrigerant compressed by the compressor (21) is condensed by the outdoor heat exchanger (22). In the refrigerant circuit (20), the air volume of the fan and the flow rate of the refrigerant are adjusted so that the refrigerant flowing out of the outdoor heat exchanger (22) becomes a liquid refrigerant. That is, the refrigerant circuit (20) is configured such that the refrigerant flowing out of the outdoor heat exchanger (22) is in a liquid state in the first cooling main operation.

    On the other hand, the remainder of the high-pressure gas refrigerant compressed by the compressor (21) flows out of the bypass pipe (18) and the first passage (31) and is mixed with the liquid refrigerant condensed in the outdoor heat exchanger (22). Thereby, this refrigerant | coolant will be in the high-pressure gas-liquid two-phase state which has desired dryness. The mixed refrigerant flows through the outdoor first communication pipe (11) and the refrigerant flow switching circuit (42) in order, and then flows into the gas-liquid separator (41). The refrigerant supplied to the gas-liquid separator (41) is in a gas-liquid two-phase state with a desired dryness. For this reason, in the gas-liquid separator (41), the ratio between the gas cold zone after separation and the liquid refrigerant can be optimally adjusted. As a result, an optimal flow rate of gas refrigerant can be supplied to the indoor unit (3A) on the heating side, and at the same time, liquid refrigerant with an optimal flow rate can be supplied to the indoor units (3B, 3C) on the cooling side.

-Effect of Embodiment 1-
According to the first embodiment, in the first cooling main operation described above, the ratio between the flow rate of the refrigerant radiated by the outdoor heat exchanger (22) and the flow rate of the refrigerant flowing out of the bypass pipe (18) is adjusted. The dryness of the refrigerant supplied to the gas-liquid separator (41) can be adjusted. As a result, the ratio of the gas refrigerant to the liquid refrigerant separated by the gas-liquid separator (41) can be easily changed, and the heating-side indoor heat exchanger (71) and the cooling-side indoor heat exchanger (71) can be changed. An optimal flow rate of refrigerant can be supplied. Here, in the said Embodiment 1, it is not the structure which divides | segments an outdoor heat exchanger into a some path | pass, and the structure of an outdoor heat exchanger (22) does not become complicated. As a result, simplification and cost reduction of the air conditioner (1) can be achieved. Only the bypass circuit (18, 31) and the adjustment mechanism (35, 81, 101) are provided, and the structure of the outdoor heat exchanger (22) is not complicated. Moreover, in Embodiment 1, the dryness of the refrigerant | coolant supplied to a gas-liquid separator (41) can be finely adjusted by controlling the flow volume of the refrigerant | coolant of a bypass pipe (18).

    Moreover, in the said Embodiment 1, the opening degree of an outdoor 1st motor operated valve (35) is adjusted according to the heating ratio at the time of the 1st cooling main operation. Therefore, in the first cooling main operation, the gas refrigerant having the optimum flow rate according to the heating ratio can be supplied to the indoor unit (3A) on the heating side, and the liquid refrigerant having the optimum flow rate is supplied to the indoor unit (3B. 3C).

<Modification of Embodiment 1>
In the modification of the first embodiment shown in FIG. 7, the gas-liquid separation unit (4) and the operation switching unit (5) in the first embodiment are integrated into one cooling / heating switching unit (6) (integrated gas-liquid separation). It is an example comprised as a unit. The configuration of the refrigerant circuit (20) is the same as that of the first embodiment.

    In this modification, the cooling / heating switching unit (6) includes a first outdoor communication piping port (6a), a second outdoor communication piping port (6b), a first indoor communication piping port (6c), and a second indoor communication piping port ( 6d). Moreover, in the modification, the intermediate part first connection pipe (15), the intermediate part second connection pipe (16), and the intermediate part third connection pipe (17) are replaced with pipes in the unit.

    Specifically, in this cooling / heating switching unit (6), the portion of the pipe corresponding to the intermediate first connecting pipe (15) of Embodiment 1 on the refrigerant circuit (20) is connected to the sixth connecting pipe (56). It is comprised by the piping extended and connected to the 1st communicating pipe (61). Further, the pipe corresponding to the intermediate part second connection pipe (16) of the first embodiment on the refrigerant circuit (20) extends the first connection pipe (51), and the second communication pipe (62) has the second connection pipe (62). It is comprised by the piping connected to the 1 branch pipe (62a). On the refrigerant circuit (20), the pipe corresponding to the intermediate third communication pipe (17) of the first embodiment extends the fifth connection pipe (55) and the second branch of the second communication pipe (62). It is comprised by the piping connected to the pipe | tube (62b).

    Since the other configuration of this modification is the same as that of the first embodiment, a detailed description thereof will be omitted. The driving operation is also the same as that of the first embodiment.

<< Reference Example 1 >>
Reference example 1 shown in FIG. 8 is a cooling / heating free type air conditioner (1) having a configuration different from that of the first embodiment. The air conditioner (1) includes an outdoor unit (2) having an outdoor circuit (20a), a cooling / heating switching unit (6) (gas-liquid separation unit) having a relay circuit (20e), and an indoor circuit (20b). And a plurality (three in FIG. 8) of indoor units (3).

    A compressor (21), an outdoor heat exchanger (22), and a four-way selector valve (80) are connected to the outdoor circuit (20a). The four-way selector valve (80) has first to fourth ports (80a, 80b, 80c, 80d). In the four-way selector valve (80), the first port (80a) is connected to the discharge side piping (26) of the compressor (21), and the second port (80b) is connected to the suction side piping (27) of the compressor (21). The third port (80c) is connected to the outdoor second connection pipe (12), and the fourth port (80d) is connected to the gas side end of the outdoor heat exchanger (22). The four-way switching valve (80) is in a first state (FIG. 8) in which the first port (80a) and the third port (80c) communicate with each other, and the second port (80b) and the fourth port (80d) communicate with each other. The state shown by the solid line), the first port (80a) and the fourth port (80d) communicate with each other, and the second port (80b) and the third port (80c) communicate with each other (dashed line in FIG. 8). The state can be switched to the state shown in FIG.

    The relay circuit (20e) includes a gas-liquid separator (41), an intermediate first electric valve (58), an intermediate third electric valve (59b), an intermediate fourth electric valve (59c), and a three-way switching valve (83) ( Switching mechanism). The refrigerant inlet (41a) of the gas-liquid separator (41) is connected to the outdoor first communication pipe (11) via the third connection pipe (53). The gas refrigerant outlet (41b) of the gas-liquid separator (41) is connected to the fifth connecting pipe (55). The liquid refrigerant outlet (41c) of the gas-liquid separator (41) is connected to each indoor first communication pipe (13) via a sixth connection pipe (56).

    The intermediate first motor operated valve (58) is connected to the sixth connecting pipe (56). The intermediate third electric valve (59b) is connected to the branch pipe (57c). The branch pipe (57c) has an inflow end connected to the third connection pipe (53) and an outflow end connected to the downstream side of the intermediate first electric valve (58) in the sixth connection pipe (56). The intermediate fourth electric valve (59c) is connected to the third connection pipe (53).

    The three-way switching valve (83) has first to third ports (83a, 83b, 83c). The first port (83a) of the three-way switching valve (83) is connected to the outdoor second communication pipe (12) via the first branch pipe (62a) and the first connection pipe (51). The second port (83b) of the three-way switching valve (83) is connected to the fifth connection pipe (55) via the second branch pipe (62b). The third port (83c) of the three-way switching valve (83) is connected to the indoor circuit (20b) via the indoor second communication pipe (14). The three-way switching valve (83) has a first state (state indicated by a solid line in FIG. 8) in which the second port (83b) and the third port (83c) communicate with each other and the first port (83a) is closed, The first port (83a) and the third port (83c) communicate with each other and can be switched to a second state (state indicated by a broken line in FIG. 8) in which the second port (83b) is closed.

Further, a bypass pipe (18) and a bypass valve (81) are connected to the outdoor circuit (20a) of Reference Example 1 . The inflow end of the bypass pipe (18) is connected to the discharge side pipe (26) of the compressor (21), and the outflow end of the bypass pipe (18) is connected to the liquid side end of the outdoor heat exchanger (22) and the chamber. It is connected between the external first connection pipe (11). The bypass valve (81) is connected to the bypass pipe (18). The bypass valve (81) is an electric valve whose opening degree is adjustable.

Since the other configuration of the reference example 1 is the same as that of the first embodiment, a specific description is omitted.

-Driving action-
The operation of the air conditioner (1) of Reference Example 1 will be described. In the air conditioner (1), the first heating main operation, the second heating main operation, the first cooling main operation, and the second cooling main operation are performed by switching.

<First heating main operation>
In the outdoor unit (2) of the first heating main operation (here, the full heating operation) shown in FIG. 9, the four-way switching valve (80) is set to the first state, and the bypass valve (81) is fully closed. . In the cooling / heating switching unit (6), the intermediate first motor-operated valve (58) and the intermediate fourth motor-operated valve (59c) are closed, the opening degree of the intermediate third motor-operated valve (59b) is adjusted, and all three-way switching is performed. The valve (83) is set to the second state. In each indoor unit (3A, 3B, 3C), the indoor expansion valve (72) is opened.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant flows into each indoor unit (3) through the outdoor second communication pipe (12). The refrigerant condenses in the indoor heat exchanger (71) and heats indoor air, then flows out from each indoor unit (3), and the indoor first communication pipe (13), sixth connection pipe (56), branch pipe (57c) flows in order, and after the pressure is reduced by the intermediate third motor operated valve (59b), the flow returns to the outdoor unit (2). The liquid refrigerant flowing into the outdoor unit (2) evaporates in the outdoor heat exchanger (22) and is sucked into the compressor (21).

<Second heating main operation>
As shown in FIG. 10, here, the second heating main operation in which heating is performed by the first and second indoor units (3A, 3B) and cooling is performed by the third indoor unit (3C) will be described. In the outdoor unit (2), the four-way switching valve (80) is set to the first state, and the bypass valve (81) is fully closed. In the cooling / heating switching unit (6), the intermediate first electric valve (58) is closed, the opening degree of the intermediate third electric valve (59b) is adjusted, and the intermediate fourth electric valve (59c) is opened. Further, the three-way switching valve (83) corresponding to the first and second indoor units (3A, 3B) is set to the second state, and the three-way switching valve (83) corresponding to the third indoor unit (3C) is set to the first state. Set to state. The indoor expansion valve (72) of the first and second indoor units (3A, 3B) is opened, and the opening degree of the indoor expansion valve (72) of the third indoor unit (3C) is adjusted.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant flows into the first and second indoor units (3A, 3B) through the outdoor second communication pipe (12), and the indoor heat exchanger ( 71) condenses and heats indoor air. The refrigerant condensed in the first and second indoor units (3A, 3B) flows into the sixth connecting pipe (56) and partly flows through the branch pipe (57c), while the rest flows through the third indoor unit (3C). Sent to.

    The refrigerant flowing through the branch pipe (57c) is depressurized by the intermediate third electric valve (59b) and then flows out to the third connection pipe (53). The refrigerant sent to the third indoor unit (3C) is depressurized by the indoor expansion valve (72), and then absorbs heat from the indoor air by the indoor heat exchanger (71) and evaporates. The gas refrigerant evaporated in the third indoor unit (3C) sequentially passes through the fifth connecting pipe (55) and the gas-liquid separator (41) and is sent to the third connecting pipe (53). In the third connection pipe (53), the gas refrigerant and the liquid refrigerant are mixed to be in a gas-liquid two-phase state. This refrigerant is sent to the outdoor unit (2), is evaporated in the outdoor heat exchanger (22), and is sucked into the compressor (21).

<First cooling operation>
As shown in FIG. 11, here, the first cooling main operation in which heating is performed by the first indoor unit (3A) and cooling is performed by the second and third indoor units (3B, 3C) will be described. In the outdoor unit (2), the four-way switching valve (80) is set to the second state, and the opening degree of the bypass valve (81) is adjusted. In the cooling / heating switching unit (6), the opening degree of the intermediate first electric valve (58) is adjusted, the intermediate fourth electric valve (59c) is opened, and the intermediate third electric valve (59b) is closed. Further, the three-way switching valve (83) corresponding to the first indoor unit (3A) is set to the first state, and the three-way switching valve (83) corresponding to the second and third indoor units (3B, 3C) is set to the second state. Set to state. In each indoor unit (3A, 3B, 3C), the indoor expansion valve (72) of the first indoor unit (3A) is opened, and the opening degree of the second and third indoor units (3B, 3C) is adjusted.

    When the compressor (21) is started, a part of the discharged high-pressure gas is condensed in the outdoor heat exchanger (22) to become a liquid refrigerant, and the rest flows through the bypass pipe (18). On the outflow side of the outdoor heat exchanger (22), the high-pressure liquid refrigerant and the gas refrigerant are mixed to form a gas-liquid two-phase state with a predetermined dryness. At this time, the opening degree of the bypass valve (81) is appropriately adjusted according to the heating ratio of the air conditioner (1) as in the first embodiment. The refrigerant whose dryness is adjusted flows into the gas-liquid separator (41) through the outdoor first communication pipe (11).

    In the gas-liquid separator (41), the gas-liquid two-phase refrigerant is separated into a gas refrigerant and a liquid refrigerant. The gas refrigerant is sent to the first indoor unit (3A) via the fifth connection pipe (55). In the first indoor unit (3A), the refrigerant heats the indoor air to condense. The refrigerant decompressed by the indoor expansion valve (72) of the first indoor unit (3A) is sent to the sixth connecting pipe (56). The liquid refrigerant separated by the gas-liquid separator (41) is sent to the second indoor unit (3B) and the third indoor unit (3C) via the sixth connection pipe (56). In the second and third indoor units (3B, 3C), after the refrigerant is depressurized by the indoor expansion valve (72), the refrigerant absorbs heat from the indoor air in the indoor heat exchanger (71) and evaporates. The evaporated refrigerant flows out to the sixth connecting pipe (56) and is mixed with the liquid refrigerant flowing out from the first indoor unit (3A), then sent to the outdoor unit (2) and sucked into the compressor (21). Is done.

<Second cooling-dominated operation>
In the outdoor unit (2) in the second cooling main operation (here, full cooling operation) shown in FIG. 12, the four-way switching valve (80) is set to the second state, and the bypass valve (81) is fully closed. . In the cooling / heating switching unit (6), the intermediate first motor-operated valve (58) and the intermediate fourth motor-operated valve (59c) are closed, the intermediate third motor-operated valve (59b) is opened, and all three-way selector valves (83 ) Is set to the second state. In each indoor unit (3A, 3B, 3C), the opening degree of the indoor expansion valve (72) is adjusted.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant is condensed in the outdoor heat exchanger (22), and then the first outdoor connection pipe (11), branch pipe (57c), sixth connection pipe ( 56) in order and flow into each indoor unit (3A, 3B, 3C). In each indoor unit (3A, 3B, 3C), the refrigerant is depressurized by the indoor expansion valve (72) and then evaporated by the indoor heat exchanger (71). The refrigerant evaporated in the indoor units (3A, 3B, 3C) is sent to the outdoor unit (2) and sucked into the compressor (21).

Also in the 1st cooling main operation of the reference example 1 , the dryness of the refrigerant | coolant supplied to a gas-liquid separator (41) can be adjusted by adjusting the opening degree of a bypass valve (81). As a result, it is possible to supply a gas refrigerant having an optimal flow rate to the indoor unit (3A) on the heating side, and to supply a liquid refrigerant having an optimal flow rate to the indoor units (3B, 3C) on the cooling side. The other effects of the reference example 1 are the same as those of the first embodiment.

<< Reference Example 2 of the Invention >>
In Reference Example 2 shown in FIG. 13, in the outdoor circuit (20a) of Reference Example 1 , the first to fourth pipes (91, 92, 93, 94) are connected in a bridge shape. Check valves (CV-5 to CV-8) are connected to the first to fourth pipes (91, 92, 93, 94), respectively. In each check valve (CV-5 to CV-8), the flow in the direction shown by the arrow in FIG. 13 is allowed, and the flow in the reverse direction is prohibited. The first pipe (91) is connected between the outdoor second communication pipe (12) and the liquid side end of the outdoor heat exchanger (22). The second pipe (92) is connected between the outdoor first communication pipe (11) and the third port (80c) of the four-way switching valve (80). The third pipe (93) is connected between the outflow end of the first pipe (91) and the outflow end of the second pipe (92). The fourth pipe (94) is connected between the inflow end of the second pipe (92) and the inflow end of the first pipe (91).

Further, in the relay circuit (20e) of Reference Example 2 , a pair of on-off valves (84, 85) (switching mechanism) is provided in place of the three-way switching valve (83) of Reference Example 1 . Specifically, in the relay circuit (20e), a first on-off valve (84) is connected to each first branch pipe (62a), and a second on-off valve (85) is connected to each second branch pipe (62b). It is connected. In the relay circuit (20e) of Reference Example 2, an eighth connection pipe (95) is connected between the first connection pipe (51) and the sixth connection pipe (56). An intermediate fifth electric valve (96) is connected to the eighth connection pipe (95).

-Driving action-
The operation of the air conditioner (1) of Reference Example 2 will be described. In the air conditioner (1), the first heating main operation, the second heating main operation, the first cooling main operation, and the second cooling main operation are performed by switching.

<First heating main operation>
In the outdoor unit (2) of the first heating main operation shown in FIG. 14, the four-way switching valve (80) is set to the first state, and the bypass valve (81) is fully closed. In the cooling / heating switching unit (6), the intermediate first electric valve (58) and the intermediate third electric valve (59b) are closed, the intermediate fourth electric valve (59c) is opened, and the intermediate fifth electric valve (96) The opening is adjusted. In the cooling / heating switching unit (6), the first on-off valves (84) corresponding to all the indoor units (3A, 3B, 3C) are closed, and the first open / close valves (84) corresponding to all the indoor units (3A, 3B, 3C) are closed. The two on-off valve (85) is opened. In each indoor unit (3), the indoor expansion valves (72) of all the indoor units (3A, 3B, 3C) are opened.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant is sent to the cooling / heating switching unit (6) through the second pipe (92) and the outdoor first communication pipe (11). This refrigerant passes through the gas-liquid separator (41) and the fifth connecting pipe (55) in this order, and flows into each indoor unit (3). The refrigerant condenses in the indoor heat exchanger (71) and heats indoor air, then flows out from each indoor unit (3), and flows through the eighth connecting pipe (95). In the eighth connection pipe (95), the refrigerant is decompressed by the intermediate fifth electric valve (96). The decompressed low-pressure liquid refrigerant returns to the outdoor unit (2), passes through the first connecting pipe (51), the outdoor second connecting pipe (12), and the first pipe (91) in this order, and then performs outdoor heat exchange. Evaporates in the vessel (22) and is sucked into the compressor (21).

<Second heating main operation>
As shown in FIG. 15, here, the second heating main operation in which heating is performed by the first and second indoor units (3A, 3B) and cooling is performed by the third indoor unit (3C) will be described. In the outdoor unit (2), the four-way switching valve (80) is set to the first state, and the bypass valve (81) is fully closed. In the cooling / heating switching unit (6), the intermediate first electric valve (58) and the intermediate third electric valve (59b) are closed, the intermediate fourth electric valve (59c) is opened, and the intermediate fifth electric valve (96). Is adjusted. In the cooling / heating switching unit (6), the first on-off valve (84) corresponding to the first and second indoor units (3A, 3B) is closed, and the second on-off valve (85) is opened. In the cooling / heating switching unit (6), the first on-off valve (84) corresponding to the third indoor unit (3C) is opened, and the second on-off valve (85) is closed. In each indoor unit (3), the indoor expansion valve (72) corresponding to the first and second indoor units (3A, 3B) is opened, and the indoor expansion valve (72) corresponding to the third indoor unit (3C) is opened. The opening is adjusted.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant is sent to the cooling / heating switching unit (6) through the second pipe (92) and the outdoor first communication pipe (11). This refrigerant passes through the gas-liquid separator (41) and the fifth connecting pipe (55) in this order, and flows into the first and second indoor units (3A, 3B). The refrigerant condenses in the indoor heat exchanger (71) and heats indoor air, and then flows out of the first and second indoor units (3A, 3B). A part of the refrigerant condensed in the first and second indoor units (3A, 3B) flows through the eighth connecting pipe (95), while the rest is sent to the third indoor unit (3C).

    The refrigerant flowing through the eighth connection pipe (95) is depressurized by the intermediate fifth electric valve (96) and then flows out to the first connection pipe (51). The refrigerant sent to the third indoor unit (3C) is depressurized by the indoor expansion valve (72), and then absorbs heat from the indoor air by the indoor heat exchanger (71) and evaporates. The gas refrigerant evaporated in the third indoor unit (3C) flows out to the first connection pipe (51) and is mixed with the liquid refrigerant flowing out of the eighth connection pipe (95) to be in a gas-liquid two-phase state. This refrigerant is sent to the outdoor unit (2) and passes through the first connecting pipe (51), the outdoor second connecting pipe (12), and the first pipe (91) in this order, and then the outdoor heat exchanger (22). Evaporates and is sucked into the compressor (21).

<First cooling operation>
As shown in FIG. 16, here, the first cooling main operation in which heating is performed by the first indoor unit (3A) and cooling is performed by the second and third indoor units (3B, 3C) will be described. In the outdoor unit (2), the four-way switching valve (80) is set to the second state, and the opening degree of the bypass valve (81) is adjusted. In the cooling / heating switching unit (6), the intermediate first electric valve (58) and the intermediate fourth electric valve (59c) are opened, and the intermediate third electric valve (59b) and the intermediate fifth electric valve (96) are closed. . In the cooling / heating switching unit (6), the first on-off valve (84) corresponding to the first indoor unit (3A, 3B) is closed, and the second on-off valve (85) is opened. In the cooling / heating switching unit (6), the first on-off valve (84) corresponding to the second and third indoor units (3B, 3C) is opened, and the second on-off valve (85) is closed. In each indoor unit (3), the indoor expansion valve (72) corresponding to the first indoor unit (3A) is opened, and the indoor expansion valve (72) corresponding to the second and third indoor units (3B, 3C) is opened. The opening is adjusted.

    When the compressor (21) is started, a part of the discharged high-pressure gas is condensed in the outdoor heat exchanger (22) to become a liquid refrigerant, and the rest flows through the bypass pipe (18). On the outflow side of the outdoor heat exchanger (22), the high-pressure liquid refrigerant and the gas refrigerant are mixed to form a gas-liquid two-phase state with a predetermined dryness. At this time, the opening degree of the bypass valve (81) is appropriately adjusted according to the heating ratio of the air conditioner (1) as in the first embodiment. The refrigerant whose dryness is adjusted flows into the gas-liquid separator (41) through the third pipe (93) and the outdoor first communication pipe (11).

    In the gas-liquid separator (41), the gas-liquid two-phase refrigerant is separated into a gas refrigerant and a liquid refrigerant. The gas refrigerant is sent to the first indoor unit (3A) via the fifth connection pipe (55). In the first indoor unit (3A), the refrigerant heats the indoor air to condense. The refrigerant decompressed by the indoor expansion valve (72) of the first indoor unit (3A) is sent to the sixth connecting pipe (56). The liquid refrigerant separated by the gas-liquid separator (41) is sent to the sixth connection pipe (56) and mixed with the liquid refrigerant condensed in the first indoor unit (3A). This refrigerant is sent to the second indoor unit (3B) and the third indoor unit (3C). In the second and third indoor units (3B, 3C), after the refrigerant is depressurized by the indoor expansion valve (72), the refrigerant absorbs heat from the indoor air in the indoor heat exchanger (71) and evaporates. The evaporated refrigerant flows through the first connecting pipe (51) and the outdoor second connecting pipe (12) and is sent to the outdoor unit (2). In the outdoor unit (2), the refrigerant flows through the fourth pipe (94) and then is sucked into the compressor (21).

<Second cooling-dominated operation>
In the outdoor unit (2) in the second cooling main operation (here, full cooling operation) shown in FIG. 17, the four-way switching valve (80) is set to the second state, and the bypass valve (81) is fully closed. . In the cooling / heating switching unit (6), the intermediate first electric valve (58), the intermediate fourth electric valve (59c), and the intermediate fifth electric valve (96) are closed, and the intermediate third electric valve (59b) is opened. The In the cooling / heating switching unit (6), the first on-off valves (84) corresponding to all the indoor units (3A, 3B, 3C) are opened, and the first open / close valves (84) corresponding to all the indoor units (3A, 3B, 3C) are opened. 2 The on-off valve (85) is closed. In each indoor unit (3), the opening degree of the indoor expansion valve (72) of all the indoor units (3A, 3B, 3C) is adjusted.

    When the compressor (21) is started, the discharged high-pressure gas refrigerant is condensed in the outdoor heat exchanger (22), and then the third pipe (93), the outdoor first connection pipe (11), the branch pipe (57c ) In order, and flows into each indoor unit (3A, 3B, 3C). In each indoor unit (3A, 3B, 3C), the refrigerant is depressurized by the indoor expansion valve (72) and then evaporated by the indoor heat exchanger (71). The refrigerant evaporated in the indoor units (3A, 3B, 3C) is sent to the outdoor unit (2). In the outdoor unit (2), the refrigerant flows through the fourth pipe (94) and then is sucked into the compressor (21).

Also in the first cooling main operation of Reference Example 2 , the dryness of the refrigerant supplied to the gas-liquid separator (41) can be adjusted by adjusting the opening degree of the bypass valve (81). As a result, it is possible to supply a gas refrigerant having an optimal flow rate to the indoor unit (3A) on the heating side and to supply liquid refrigerant having an optimal flow rate to the indoor units (3B, 3C) on the cooling side. The other effects of the reference example 2 are the same as those of the first embodiment and the reference example 1 .

    As described above, the present invention is useful for an air conditioner configured to perform an operation in which cooling and heating are mixed in an air conditioner having a plurality of indoor heat exchangers.

2 Outdoor unit
4 Gas-liquid separation unit
6 Cooling / heating switching unit (gas-liquid separation unit)
10 Air conditioner
11 1st connecting pipe outside the room (1st connecting pipe)
12 Second communication pipe outside the room (second communication pipe)
18 Bypass pipe (bypass circuit)
20 Refrigerant circuit
20a Outdoor circuit
20c First relay circuit (relay circuit)
20e relay circuit
21 Compressor
22 Outdoor heat exchanger
31 1st passage (bypass circuit)
35 Outdoor first motorized valve (bypass valve, adjusting mechanism)
41 Gas-liquid separator
63 1st switching valve (switching mechanism)
64 2nd switching valve (switching mechanism)
71 Indoor heat exchanger
81 Bypass valve (adjustment mechanism)
83 Three-way switching valve (switching mechanism)
84 First on-off valve (switching mechanism)
85 Second on-off valve (switching mechanism)
101 Bypass control valve (adjustment mechanism)

Claims (6)

A refrigerant circuit (20) to which a compressor (21), an outdoor heat exchanger (22), a gas-liquid separator (41), and a plurality of indoor heat exchangers (71) are connected; In (20), the gas refrigerant separated by the gas-liquid separator (41) is radiated by some indoor heat exchangers (71), and at the same time, the liquid refrigerant separated by the gas-liquid separator (41) is partially An air conditioner equipped with a refrigerant circuit (20) configured to allow a refrigeration cycle to evaporate in the indoor heat exchanger (71) and perform heating and cooling simultaneously,
A bypass circuit for bypassing a part of the high-pressure gas refrigerant discharged from the compressor (21) between the liquid side end of the outdoor heat exchanger (22) and the inflow end of the gas-liquid separator (41) (18,31) and
An adjustment mechanism ( 35 ) for adjusting the ratio of the flow rate of the refrigerant flowing out of the bypass circuit (18, 31) to the flow rate of the refrigerant flowing out of the outdoor heat exchanger (22);
An open / close mechanism (35) for opening and closing the flow path of the refrigerant, communicating the discharge side of the compressor (21) with the first connecting pipe (11), and connecting the suction side of the compressor (21) A first state in which the two communication pipes (12) are communicated, a discharge side of the compressor (21) and the second communication pipe (12), and a suction side of the compressor (21). And a switching circuit (25) for switching to a second state in which the first communication pipe (11) is communicated with,
The air conditioning apparatus, wherein the adjustment mechanism (35) also serves as an opening / closing mechanism for the switching circuit (25) . In claim 1,
The adjustment mechanism ( 35 ) is configured to increase the ratio as the ratio of the overall heating load to the overall cooling load of the plurality of indoor heat exchangers (71) increases. Air conditioner. In claim 1 or 2,
The air conditioner characterized in that the refrigerant circuit (20) is configured such that the refrigerant after radiating heat to the outdoor air by the outdoor heat exchanger (22) becomes a liquid refrigerant. In any one of Claims 1 thru | or 3,
An outdoor unit (2) having an outdoor circuit (20a) to which the compressor (21) and the outdoor heat exchanger (22) are connected;
A gas-liquid separation unit (4, 6) having a relay circuit (20c, 20e) to which the gas-liquid separator (41) is connected;
An air conditioner comprising: two connecting pipes (11, 12) for connecting the outdoor circuit (20a) and the relay circuit (20c, 20e). In claim 4,
A switching mechanism (63, 64, 83, 84, 85) for switching the flow of liquid refrigerant and gas refrigerant in the indoor heat exchanger (71) is connected to the relay circuit (20c, 20e). An air conditioner characterized by. In any one of Claims 1 thru | or 5,
The air conditioner characterized in that the refrigerant of the refrigerant circuit (20) is difluoromethane.

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