JP2698175B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial application field The present invention is composed of an outdoor unit and a plurality of indoor units, and simultaneously cools or heats all of the plurality of rooms and simultaneously cools a certain room. The present invention relates to a multi-room air conditioner that heats another room.

(B) Conventional technology A multi-room air conditioner capable of simultaneously cooling or heating all of a plurality of rooms and simultaneously cooling a certain one of the plurality of rooms to heat a plurality of rooms is disclosed in Japanese Patent Publication No. 5224710/1972. No. 52-24711, Japanese Patent Publication No. 52-27459, and Japanese Utility Model Publication No. 54-3020.

(C) Problems to be Solved by the Invention The devices presented in the above-mentioned JP-B-52-24710 and JP-B-52-24711 require four-way switching valves and outdoor heat exchangers by the number of indoor units. The piping circuit configuration becomes complicated and the manufacturing cost is high. Further, since two unit pipes have to be drawn out of the outdoor unit for each indoor unit, the number of unit-unit pipes is increased and piping work is troublesome. Had disadvantages. Moreover, at the same time, during the cooling / heating operation for cooling one room and heating the other room, the outdoor heat exchangers corresponding to the respective indoor units act as condensers and evaporators, respectively, and dissipate heat to the outside. there were.

In addition, the above-mentioned JP-B-52-27459 and JP-B-54-302.
In the device presented in Japanese Patent Publication No. 0, at the time of the cooling / heating operation for cooling a certain room of a plurality of rooms and heating the other room at the same time, a combination of a room capable of cooling and a room capable of heating is determined, and the cooling / heating operation is freely performed in each room. There was a drawback that it could not be selected and performed, and the usability was poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-room air conditioner that solves the above-mentioned problems and provides stable cooling and heating capacity.

(D) Means for Solving the Problems According to the present invention, one end of each of a plurality of outdoor heat exchangers is branched and connected to a refrigerant discharge pipe and a refrigerant suction pipe of a compressor via an outdoor switching valve, and this suction is performed. The branch pipe is provided with a check valve for preventing the refrigerant from flowing into the outdoor heat exchanger, and the inter-unit piping provided between the outdoor unit and the plurality of indoor units is connected to the high pressure branch pipe connected to the discharge pipe. Gas pipes,
A low-pressure gas pipe branched and connected to the suction pipe, and a liquid pipe connected to the other ends of the plurality of outdoor heat exchangers. One end of each indoor heat exchanger is connected to the high-pressure gas pipe and the low-pressure gas pipe. A branch connection is made to the pipe via an indoor switching valve, and the other end of each indoor heat exchanger is connected to the liquid pipe via a refrigerant pressure reducer.

In addition, the present invention branches and connects one end of each of the plurality of outdoor heat exchangers to a refrigerant discharge pipe and a refrigerant suction pipe of a compressor via an outdoor switching valve, and includes an outdoor unit and a plurality of indoor units. A high-pressure gas pipe branched and connected to the discharge pipe, a low-pressure gas pipe branched and connected to the suction pipe, and a liquid connected to the other ends of the plurality of outdoor heat exchangers. And one end of each indoor heat exchanger is branched and connected to the high-pressure gas pipe and the low-pressure gas pipe via an indoor switching valve, and the other end of each indoor heat exchanger is connected to the liquid pipe by a refrigerant. A controller is connected via a decompressor to open the outdoor switching valve in order to intermittently guide the refrigerant discharged from the compressor to the suspended outdoor heat exchanger.

(E) Operation When cooling all the rooms at the same time, the compressor is discharged by setting the outdoor switching valve of each outdoor heat exchanger and the indoor switching valve of each indoor heat exchanger to the cooling state. The refrigerant flowed from the discharge pipe to the outdoor heat exchangers in parallel and condensed and liquefied here, and then distributed to the refrigerant decompressors of each indoor unit via the liquid pipes, and then evaporated and vaporized in each outdoor heat exchanger. Thereafter, the refrigerant is sucked into the compressor through the low-pressure gas pipe and the refrigerant suction pipe sequentially. Thus, all the rooms are cooled by each indoor heat exchanger acting as an evaporator.

When heating all the rooms at the same time, the refrigerant discharged from the compressor is set by setting the outdoor switching valve of each outdoor heat exchanger and the indoor switching valve of each indoor heat exchanger to the heating state. After being sequentially distributed to each indoor heat exchanger through a discharge pipe and a high-pressure gas pipe, and condensed and liquefied here, they are merged in a liquid pipe through each refrigerant decompressor, and then flow into each outdoor heat exchanger in parallel. After being evaporated and vaporized respectively, they are sucked into the compressor via the refrigerant suction pipe. In this way, all the rooms are heated by each indoor heat exchanger acting as a condenser.

In addition, when simultaneously cooling any two rooms and heating one room, for example, set the outdoor switching valve of one outdoor heat exchanger to the cooling state and close the outdoor switching valve of the other outdoor heat exchanger. When the indoor switching valve of the indoor heat exchanger of the indoor unit to be cooled is set to the cooling state and the indoor switching valve of the indoor heat exchanger of the indoor unit to be heated is set to the heating state, the refrigerant is discharged from the compressor. A part of the refrigerant flows only to one of the outdoor heat exchangers, and the remaining refrigerant flows to the indoor heat exchanger of the indoor unit for heating through the high-pressure gas pipe, and is condensed and liquefied by the indoor heat exchanger and the outdoor heat exchanger. You. The refrigerant condensed and liquefied by these heat exchangers is distributed to the refrigerant decompressor of each indoor unit via a liquid pipe, and then evaporated and vaporized by each indoor heat exchanger. Thereafter, the low-pressure gas pipe and the refrigerant suction pipe are formed. Are sequentially sucked into the compressor. Thus, one room is heated by the indoor heat exchanger acting as a condenser, and two rooms are cooled by another indoor heat exchanger acting as an evaporator.

During the simultaneous cooling and heating operation, when the outside air temperature is 0 ° C. or lower, the refrigerant evaporation pressure of the indoor heat exchanger that is performing the cooling operation becomes higher than the refrigerant pressure in the outdoor heat exchanger that is being stopped. An attempt is made to flow into the suspended outdoor heat exchanger through the one-way outdoor switching valve of the suction branch pipe, but the refrigerant flows into the outdoor heat exchanger because the suction branch pipe is provided with a reverse valve. Therefore, the amount of the circulated refrigerant does not decrease due to the accumulation of the refrigerant, and the cooling / heating capacity does not decrease.

In addition, when the check valve is not completely closed due to the small refrigerant pressure difference and the refrigerant gradually flows into the outdoor heat exchanger, the outdoor switching valve in the discharge branch pipe of the outdoor heat exchanger is intermittently operated. Since the refrigerant accumulated in the outdoor heat exchanger is expelled by the pressure of the high-pressure discharge gas refrigerant, the refrigerant circulation amount is reduced and the cooling / heating capacity is reliably prevented from being reduced.

(F) Embodiment An embodiment of the present invention will be described with reference to the drawings.
The outdoor heat exchanger (3) has a different heat exchange capacity from the compressor (2).
a) an outdoor unit having (3b) and (3c) and a gas-liquid separator (4); (5a), (5b) and (5c) having the same heat exchanger capacity;
Alternatively, an indoor unit having different indoor heat exchangers (6a) (6b) (6c), and one end of each of the outdoor heat exchangers (3a) (3b) (3c) is connected to the refrigerant discharge pipe (7) of the compressor (2). ) And the refrigerant suction pipe (8) are connected to the outdoor switching valves (9a) (10a), (9b) (10
b), (9c) and (10c) are branched and connected, and the inter-unit piping (11) connecting the outdoor unit (1) and the indoor units (5a) (5b) (5c) is connected to the refrigerant discharge pipe (7). ), A low pressure gas pipe (13) branched and connected to the refrigerant suction pipe (8), and an outdoor heat exchanger (3a).
(3b) (3c) and the connected liquid pipe (14), each indoor heat exchanger (6a) (6b) (6c) high pressure gas pipe (12) and low pressure gas pipe (13) Have switching valves (15a) and (16a),
(15b) (16b), (15c) and (16c) are branched and connected, and the liquid pipe (14) is connected to a refrigerant pressure reducer (17
a) Connected via (17b) and (17c).

(18a) (18b) (18c) are auxiliary refrigerant decompressors such as electric expansion valves provided in the liquid pipe (14), and (19a) (19b) (19c) are suction branch pipes (8a) (8b) (8c ), A check valve that prevents refrigerant from flowing into the suspended outdoor heat exchanger (3a) or (3b) or (3c), and (20) compresses the unused outdoor heat exchanger. Discharge refrigerant from the machine (2) to the discharge branch pipe (7
a) or (7b) or (7c) to open and close the outdoor switching valve (9a) or (9b) or (9c) for intermittent guidance, while other outdoor switching valves (10a) (10b) This is a controller that adjusts the opening and closing of (10c) and the valve opening of the auxiliary refrigerant decompressors (18a) (18b) (18c).

Next, the driving operation will be described. When cooling all the rooms at the same time, one outdoor switching valve (9a) (9b) (9c) of each of the outdoor heat exchangers (3a) (3b) (3c) is opened and the other outdoor switching valve ( 10a) (10b) (10c) is closed and one indoor side switching valve (15a) of the indoor heat exchangers (6a) (6b) (6c)
(15b) (15c) is closed and the other indoor switching valve (16
a) By opening (16b) and (16c), the refrigerant discharged from the compressor (2) is discharged from the discharge pipe (7) to the switching valve (9a).
(9b), (9c), co-current with the outdoor heat exchangers (3a), (3b), (3c) and condensed and liquefied here, then through the liquid pipe (14), each indoor unit (5a) (5b) (5c) Refrigerant decompressor (17a) (17b)
(17c), where the pressure is reduced. Then, after evaporating and evaporating in each indoor heat exchanger (6a) (6b) (6c), the indoor side switching valves (16a) (16b) (16c) and low-pressure gas pipe (1
3), sucked into the compressor (2) through the suction port (8) and the gas-liquid separator (4) sequentially. Thus, all the rooms are simultaneously cooled by the indoor heat exchangers (6a) (6b) (6c) acting as evaporators.

At the time of such cooling operation, for example, when the indoor unit (5b) is turned off and the cooling operation is stopped to reduce the cooling load,
Outdoor switching valve (9b) for one of the outdoor heat exchangers (3b)
(10b) and the auxiliary refrigerant decompressor (18b) are closed, the outdoor heat exchanger (3b) stops operating as a condenser, and is operated with a condenser capacity corresponding to the cooling load. Also, when this operation is performed in summer when the outside air temperature is high, the pressure in the unused outdoor heat exchanger (3b) is higher than the refrigerant evaporation pressure of the indoor heat exchangers (6a) (6c). The low-pressure refrigerant does not flow into the branch pipe (8b), but the equipment such as a computer generates heat even in winter when the outside air temperature is lower than 0 ° C, so the indoor units (5a) and (5c) are cooled. In this case, the refrigerant evaporation pressure of the indoor heat exchangers (6a) and (6c) of both indoor units becomes higher than the refrigerant pressure in the inactive outdoor heat exchanger (3b). Let's flow into the heat exchanger (3b) through the outdoor switching valve (10b) which is unidirectional (closes completely in the direction of the arrow shown in the figure, but opens in the opposite direction due to the refrigerant pressure difference). However, since the suction branch pipe (8b) is provided with a check valve (19b), this outdoor heat exchange Vessel (3b) to never refrigerant accumulate therein from flowing, never cooling and heating ability is reduced decreases the amount of circulating refrigerant by narrowing reservoir of the refrigerant.

Also, since the refrigerant pressure difference described above is small, the check valve (19
If the refrigerant does not close completely and the refrigerant gradually flows into the outdoor heat exchanger (3b), the outdoor switching valve (9b) in the discharge branch pipe (7b) of the outdoor heat exchanger (3b) and the auxiliary refrigerant Pressure reducer (18
b) is intermittently opened every few hours by a signal from the controller (20), and the pressure of the high-pressure discharge gas refrigerant expels the refrigerant accumulated in the outdoor heat exchanger (3b). It is surely prevented that the amount of refrigerant circulating is reduced and the cooling / heating capacity is reduced.

Conversely, when heating all rooms at the same time, use an outdoor heat exchanger (3
a) One of the outdoor switching valves (9a) (9b) (9
Close c) and the other outdoor switching valve (10a) (10b)
Open (10c) and indoor heat exchangers (6a) (6b) (6c)
By opening one indoor switching valve (15a) (15b) (15c) and closing the other indoor switching valve (16a) (16b) (16c), the refrigerant discharged from the compressor (2) Switching valve (15a) through discharge pipe (7) and high-pressure gas pipe (12) sequentially
(15b) (15c), distributed to indoor heat exchangers (6a) (6b) (6c), where they are condensed and liquefied respectively, and then decompressed by each refrigerant decompressor (17a) (17b) (17c) The liquid pipes (14) are merged, and after that, after being evaporated and vaporized in the outdoor heat exchangers (3a) (3b) (3c), the switching valves (10a) (10b) (10c), the suction pipe (8), It is sucked into the compressor (2) through the gas-liquid separator (4) sequentially. Thus, all the rooms are simultaneously heated by the indoor heat exchangers (6a) (6b) (6c) acting as condensers.

At the time of such a heating operation, for example, when the indoor unit (5b) is turned off and the heating operation is stopped to reduce the heating load,
For example, the switching valves (9b) and (10b) of the outdoor heat exchanger (3b) are closed, the outdoor heat exchanger (3b) stops operating as an evaporator, and is operated with an evaporator capacity suitable for the heating load.

In addition, in the case of cooling two rooms simultaneously and heating one room at the same time, for example, one outdoor switching valve (9) of the outdoor heat exchanger (3b) is used.
b) is opened, and both the switching valves (9a) (10a), (9) of the other outdoor heat switching valve (10b) and the outdoor heat exchangers (3a) (3c) are opened.
c) Indoor unit (5a) that closes (10c) and cools
(5c) one indoor side switching valve (15a) (15c) is closed and the other indoor side switching valve (16a) (16c) is opened and one indoor side switching valve (5b) of the indoor unit (5b) is heated. Fifteen
When b) is opened and the other indoor switching valve (16b) is closed, a part of the refrigerant discharged from the compressor (2) passes through the discharge pipe (7) and the switching valve (9b) in that order, and one of the outdoor heat is switched. The refrigerant flows only to the exchanger (3b) and the adjacent refrigerant flows into the high-pressure gas pipe (1
2) The switching valve (15) of the indoor unit (5b) that heats through
b), flows to the indoor heat exchanger (6b), and is condensed by the indoor heat exchanger (6b) and the outdoor heat exchanger (3b). The refrigerant condensed and liquefied in the heat exchangers (6b) and (3b) is decompressed by the refrigerant decompressors (17a) and (17c) in the indoor units (5a) and (5c) via the liquid pipe (14). Each of the indoor heat exchangers (6a) and (6c) evaporates and evaporates, and then merges with the low-pressure gas pipe (13) through each indoor side switching valve (16a) (16c).
It is sucked into the compressor (2) through the suction pipe (8) and the gas-liquid separator (4) in order. In this way, one room is heated by the indoor heat exchanger (6b) acting as a condenser, and two rooms are cooled by the other indoor heat exchangers (6a) (6c) acting as an evaporator.

During the simultaneous cooling and heating operation, in winter, when the outside air temperature is lower than 0 ° C., the refrigerant evaporation pressure of the indoor heat exchangers (6a) and (6c) is lower than the refrigerant pressure in the suspended outdoor heat exchangers (3a) and (3c). And the refrigerant pressure difference causes the inflowing outdoor heat exchangers (3a) (3c) and the suction branch pipes (8a) (8c) to flow through the one-way outdoor switching valves (10a) (10c). However, check valves (19a) (19) are connected to the suction branch pipes (8a) (8c).
Since c) is provided, the refrigerant does not flow into and accumulate in the indoor heat exchangers (3a) and (3c), and the amount of refrigerant circulated by the accumulation of refrigerant does not decrease, and the cooling / heating capacity does not decrease.

Also, since the refrigerant pressure difference described above is small, the check valve (19
a) (19c) is not completely closed and the outdoor heat exchanger (3a) (3c)
If the refrigerant gradually flows into the outdoor heat exchanger (3a)
The outdoor switching valves (9a) (9c) and the auxiliary refrigerant pressure reducers (18a) (18c) in the discharge branch pipes (7a) (7c) of (3c) are output every several hours by a signal from the controller (20). The outdoor heat exchanger (3a) (3
Since the refrigerant accumulated in c) is expelled, the amount of circulating refrigerant is reduced and the cooling / heating capacity is reliably prevented from lowering.

Further, if such simultaneous cooling and heating operation is performed in summer when the outside air temperature is high, the outdoor heat exchanger (3b) alone cannot sufficiently draw a heat source from outside air, and the cooling capacity is reduced. In such an operation state, the switching valve (9a) is opened, and a part of the refrigerant discharged from the discharge pipe (7) is discharged to the other outdoor heat exchanger (3).
After flowing to a) and condensed and liquefied, it passes through the auxiliary refrigerant decompressor (18a) and joins to the liquid pipe (14). The outdoor heat exchanger (3a) acting as a condenser further heats from outside air to a heat source. To prevent a decrease in cooling capacity. During this summer operation, for example, the indoor unit (5c) is thermo-off and the cooling operation is stopped, and when the cooling load is reduced, the amount of heat source pumped from the outside air may be small. For example, one of the switching valves (9a) ( 10a) is closed and only the other outdoor heat exchanger (3b) acts as a condenser.

Next, when cooling one room and heating two rooms, it is possible to operate the auxiliary refrigerant decompressors (18a), (18b), and (18c) appropriately.

For example, when cooling with the indoor unit (5b) and heating with the indoor units (5a) (5c), one outdoor switching valve (10c) of the outdoor heat exchanger (3c) is opened and the other outdoor switching valve ( 9a) (9b) (9c) (10a) (10b) is closed and one indoor side switching valve (15
b) is closed and the other indoor switching valve (16b) is opened,
In addition, when one indoor switching valve (15a) (15c) of the indoor unit (5a) (5c) to be heated is opened and the other indoor switching valve (16a) (16c) is closed, the compressor (2) discharges. The discharged refrigerant is sequentially distributed to the indoor side switching valves (15a) (15c) through the discharge pipe (7) and the high pressure gas pipe (12), and is condensed and liquefied in the respective indoor heat exchangers (6a) (6c). . The liquefied refrigerant flows into the liquid pipe (14) via the refrigerant decompressors (17a) (17c) which are fully opened, respectively, and a part of the liquid refrigerant in the liquid pipe is decompressed by the refrigerant decompression section (17b). After the indoor heat exchanger (6b)
After the remaining liquid refrigerant is decompressed by the auxiliary refrigerant decompressor (18c), it is evaporated and vaporized by the outdoor heat exchanger (3c), and sequentially passes through the suction pipe (8) and the gas-liquid separator (4). It is sucked into the compressor (2). In this way, two rooms are heated by the indoor heat exchangers (6a) and (6c) acting as condensers, and one room is cooled by another indoor heat exchanger (6b) acting as an evaporator.

During the simultaneous cooling and heating operation, in winter, when the outside air temperature is lower than 0 ° C., the refrigerant evaporation pressure of the indoor heat exchanger (6c) becomes higher than the refrigerant pressure in the paused outdoor heat exchangers (3a) and (3b). Due to the refrigerant pressure difference, this paused outdoor heat exchanger (3
a) Attempt to flow to (3b) through the unidirectional outdoor switching valves (10a) (10b) of the suction branch pipes (8a) (8b). Since the stop valves (19a) and (19b) are provided, the refrigerant does not flow into and accumulate in the outdoor heat exchangers (3a) and (3b). It does not decline.

Also, since the refrigerant pressure difference described above is small, the check valve (19
a) (19b) is not completely closed and the outdoor heat exchanger (3a) (3b)
If the refrigerant gradually flows into the outdoor heat exchanger (3a)
The outdoor switching valves (9a) (9b) and the auxiliary refrigerant pressure reducers (18a) (18b) in the discharge branch pipes (7a) (7b) of (3b) are output every several hours by a signal from the controller (20). The outdoor heat exchanger (3a) is opened intermittently by the pressure of the high-pressure discharge gas refrigerant.
(3b) Because the refrigerant that has accumulated inside is expelled,
It is surely prevented that the amount of refrigerant circulating is reduced and the cooling / heating capacity is reduced.

If such simultaneous cooling and heating operation is performed in winter when the outside air temperature is low, the outdoor heat exchanger (3c) alone cannot sufficiently draw a heat source from outside air, and the heating capacity is reduced. In such an operating state, the switching valve (10b) is opened, and the auxiliary refrigerant decompressor (18b) is operated to activate the other outdoor heat exchanger (3b).
Also acts as an evaporator, so that a decrease in the heating capacity is prevented. During this winter operation, for example, when the indoor unit (5c) is turned off and the heating operation is stopped, and the heating load is reduced, the amount of heat source pumped from the outside air may be small. For example, one switching valve (9a) (9b) (9c) (10
a) (10c) is closed and only the other outdoor heat exchanger (3b) acts as an evaporator.

Thus, each indoor unit (5a) (5b) (5c) has its own indoor switching valve (15a) (16a), (15b) (16b),
(15c) (16c) and each outdoor switching valve (9a) (10a), (9b) (10b), (9c) of the outdoor heat exchanger (3a) (3b) (3c)
By opening and closing (10c), the cooling and heating operation can be performed arbitrarily, and the indoor units (5a) (5b) (5c)
By using the outdoor heat exchangers (3a), (3b), and (3c) with different heat exchange capacities according to the number of operating units and the cooling and heating load, efficient cooling and heating can be performed, and as an evaporator and condenser during simultaneous cooling and heating operation Heat recovery is performed in each of the working indoor heat exchangers (6a), (6b), and (6c), and operation efficiency can be improved.

When the outdoor heat exchangers (3a), (3b), and (3c) acting as evaporators are frosted during the heating operation of all the rooms, one of the switching valves (9c) is opened and the other switching valve (10c) is opened. The defrosting of the outdoor heat exchanger (3c) is performed by closing and guiding a part of the high-temperature discharge refrigerant from the discharge pipe (7) to the one outdoor heat exchanger (3c). While closing the valve (9c) and opening the other switching valves (10a) (10b), one outdoor heat exchanger (3c) again acts as an evaporator,
Open the switching valves (9a) and (9b) and close the switching valves (10a) and (10b), and connect the discharge pipe (7) to the other outdoor heat exchangers (3a) and (3b).
The outdoor heat exchangers (3a) (3b) (3c) are alternately defrosted, such as by defrosting the outdoor heat exchangers (3a) (3b) by guiding a part of the high-temperature discharged refrigerant from the All rooms heating operation is performed continuously.

In addition, one of the outdoor heat exchangers (3a), (3b), and (3c) functions as an evaporator and the other functions as an evaporator in the simultaneous cooling and heating operation in which the other is stopped. If the switch (3c) is frosted, one of the switching valves (9c) (10
c) is switched to defrost the outdoor heat exchanger (3c), and at the same time, the other switching valves (10a) and (10b) are opened to allow the stopped outdoor heat exchangers (3a) and (3b) to function as evaporators. As a result, the simultaneous cooling and heating operation is continuously performed.

In the above embodiment, three indoor units (5a) (5b)
(5c) was used, but even in the case of four or more indoor units having different capacities, it is only necessary to branch and connect to the unit-to-unit piping (11), and the outdoor heat exchanger is installed in accordance with the number of indoor units. By branch connection, the number of outdoor heat exchangers can be easily increased.

In the above embodiment, the switching valves (9a) (10a), (9b)
(10b), (9c) (10c), (15a) (16a), (15b) (1
6b), (15c) and (16c) each use a two-way valve. Instead of this, the switching valves (9a) and (10a) are replaced with three-way valves, and the switching valve (9b)
A total of six three-way valves may be used, such as three-way valves in (10b).

In the above embodiment, the plurality of outdoor heat exchangers (3a) (3
b) (3c) was formed separately, but these outdoor heat exchangers (3c)
a) (3b) may be formed integrally.

(G) Effects of the Invention The present invention provides a high-pressure gas pipe and a low-pressure gas pipe for connecting an outdoor unit incorporating a plurality of outdoor heat exchangers and a plurality of indoor units incorporating an indoor heat exchanger. Since it is composed of three refrigerant pipes, a pipe and a liquid pipe, any number of indoor units can be combined simply by branch connection to the pipes between the units, and simultaneous cooling operation and simultaneous heating of a plurality of indoor units can be performed. In addition to the operation, the simultaneous cooling and heating operation can be freely selected and performed by any indoor unit, and at the same time of the simultaneous cooling operation and simultaneous heating operation and the simultaneous cooling and heating operation, a plurality of outdoor heat exchangers according to the cooling and heating load. , It is possible to perform an efficient cooling and heating operation under an optimum refrigerant pressure.

In addition, a check valve is provided on the suction branch pipe of the outdoor heat exchanger to prevent the low-pressure gas refrigerant from accumulating in the inactive outdoor heat exchanger. If it cannot be prevented, the outdoor switching valve in the discharge branch pipe is opened intermittently to expel the refrigerant accumulated in the outdoor heat exchanger, so that the amount of circulating refrigerant is reduced and the cooling / heating capacity is prevented from being reduced. be able to.

In addition, at the time of simultaneous cooling and heating operation, the indoor heat exchanger acting as a condenser and the indoor heat exchanger acting as an evaporator are connected in series, so that efficient operation by heat recovery can be performed.

[Brief description of the drawings]

The drawing is a refrigerant circuit diagram of an air conditioner showing an embodiment of the present invention. (1) Outdoor unit (2) Compressor (3a)
(3b) (3c) ... outdoor heat exchanger, (5a) (5b) (5c) ...
... indoor unit, (6a) (6b) (6c) ... indoor heat exchanger, (7) ... refrigerant discharge pipe, (8) ... refrigerant suction pipe,
(8a) (8b) (8c) ... Suction branch pipe, (9a) (10a),
(9b) (10b), (9c) (10c)… indoor switching valve, (1
1) Piping between units, (12) High-pressure gas pipe, (1
3) Low-pressure gas pipe, (14) Liquid pipe, (15a) (16
a), (15b) (16b), (15c) (16c) ... indoor switching valve, (17a) (17b) (17c) ... refrigerant decompressor, (19a)
(19b) (19c) ... check valve, (20) ... controller.

Continuing on the front page (72) Keizo Nakamoto, Inventor 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Kazushige Omi 2-18-3 Keihanhondori, Moriguchi-shi, Osaka Yo Electric Co., Ltd.

Claims (2)

(57) [Claims] An air conditioner in which an outdoor unit containing a compressor and a plurality of outdoor heat exchangers and a plurality of indoor units containing an indoor heat exchanger are connected by unit piping. One end of each of the outdoor heat exchangers is branched and connected to the refrigerant discharge pipe and the refrigerant suction pipe of the compressor via an outdoor switching valve, and the refrigerant is prevented from flowing into the outdoor heat exchanger through the suction branch pipe. A high-pressure gas pipe branch-connected to the discharge pipe, a low-pressure gas pipe branch-connected to the suction pipe, and the other ends of the plurality of outdoor heat exchangers. One end of each indoor heat exchanger is branched and connected to the high-pressure gas pipe and the low-pressure gas pipe via an indoor switching valve, and the other end of each indoor heat exchanger is connected to the liquid pipe. Air conditioning characterized by being connected to a pipe via a refrigerant pressure reducer Location. 2. An air conditioner in which an outdoor unit containing a compressor and a plurality of outdoor heat exchangers and a plurality of indoor units containing an indoor heat exchanger are connected by unit piping. While one end of each of the outdoor heat exchangers is branched and connected to a refrigerant discharge pipe and a refrigerant suction pipe of a compressor via an outdoor switching valve, a unit-to-unit pipe is connected to the discharge pipe and a high-pressure gas pipe branched and connected. A low-pressure gas pipe branched and connected to the suction pipe, and a liquid pipe connected to the other ends of the plurality of outdoor heat exchangers. One end of each indoor heat exchanger is connected to the high-pressure gas pipe and the low-pressure gas pipe. A branch connection to the gas pipe is made via an indoor switching valve, and the other end of each indoor heat exchanger is connected to the liquid pipe via a refrigerant decompressor, and the discharge from the compressor to the suspended outdoor heat exchanger. A controller for opening and closing the outdoor switching valve for intermittently guiding the refrigerant is provided. An air conditioning apparatus, characterized in that the.