JPH0293263A - Air conditioning device - Google Patents

Abstract

PURPOSE:To prevent the generation of refrigerant noise due to a difference in a refrigerant pressure by a method wherein, during simultaneous cooling heating operation, a second on-off valve is closed and a third on-off valve is opened, and during switching from heating to cooling operation, a high pressure refrigerant in an indoor heat exchanger flows through a bypass pipe to a liquid pipe, and after a refrigerant pressure is reduced, the second on-off valve is opened. CONSTITUTION:When two rooms are cooled and one room is heated, the one switching valve 9a of an outdoor heat exchanger 3 is opened and simultaneously the other switching valve 9b is closed. Further, first on-off valves 16a and 16c of indoor units 5a and 5c where cooling is effected are closed and simultaneously second on-off valves 17a and 17c and third on-off valves 23a and 23c are opened, and a first on-off valve 16b of an indoor unit 5b where heating is effected is opened and simultaneously a second on-off valve 17b and a third on-off valve 23b are closed. When, during heating operation of all rooms, for example, only the indoor unit 5b is switched to cooling operation, a high pressure refrigerant flows to a liquid pipe 13 through a bypass pipe 21b by means of which the first on-off valve 16b and a refrigerant pressure reducer 18b are closed, and after a refrigerant pressure in an indoor heat exchanger 6b is reduced, the second on-off valve 17b is closed.

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 can simultaneously cool or heat all of the plurality of rooms and cool any room at the same time. This invention relates to a multi-room air conditioner that heats other rooms.

(B) Prior art A multi-room air conditioner that can cool or heat all of multiple rooms at the same time, and that can simultaneously cool one room and heat the other rooms, is disclosed in Japanese Patent Publication No. 52-24710 and Japanese Patent Publication No. 52-24710. 52-2
It has been fully presented in Publication No. 4711 and Publication No. 3020 of 1983.

(c) Problem to be solved by the invention The above-mentioned Japanese Patent Publication No. 52-24710 and Japanese Patent Publication No. 52-
The device presented in Publication No. 24711 requires as many four-way switching valves and outdoor heat exchangers as there are indoor units, which complicates the piping circuit configuration, increases manufacturing costs, and requires two valves for each indoor unit. Since the inter-unit piping must be drawn out from the outdoor unit, the number of inter-unit piping increases, making the piping work cumbersome.Moreover, during air-conditioning operation that cools one room and heats another room at the same time. However, the outdoor heat exchanger that corresponds to each indoor unit functions as a condenser and an evaporator, respectively, and discards heat outdoors, which has the disadvantage that heat cannot be recovered.

Furthermore, in the device disclosed in the above-mentioned Japanese Utility Model Publication No. 54-3020, during air-conditioning operation in which multiple rooms are cooled and other rooms are heated at the same time, the combination of rooms that can be cooled and rooms that can be heated is determined. It is not possible to freely select and perform operations in each room, which has the disadvantage of being inconvenient to use.

The present invention solves the above-mentioned problems and provides a multi-room air conditioner that prevents the generation of refrigerant noise and the freezing of an indoor heat exchanger.

(d) Means for Solving the Problems The present invention connects one end of an outdoor heat exchanger to a refrigerant discharge pipe and a refrigerant suction pipe of a compressor via a switching valve, while connecting an outdoor unit and a plurality of indoor units. and the high pressure gas pipe connected to the refrigerant discharge pipe of the compressor, and
It consists of a low pressure gas pipe connected to the refrigerant suction pipe of the compressor, and a liquid pipe connected to the other end of the outdoor heat exchanger, and one end of each indoor heat exchanger is connected to the high pressure gas pipe. The on-off valve is branch-connected to the low-pressure gas pipe through a second on-off valve, and connected to the liquid pipe via a refrigerant pressure reducer, and has a refrigerant throttling resistor in parallel with the second on-off valve. A bypass pipe and/or a third on-off valve are connected thereto.

(*) Effect When cooling all rooms at the same time, set the switching valve of the outdoor heat exchanger to the cooling state and set the switching valve of the outdoor heat exchanger to the cooling state. By closing the third on-off valve and opening the second on-off valve, the refrigerant discharged from the compressor flows from the discharge pipe to the outdoor heat exchanger where it is condensed and liquefied, and then passes through the liquid pipe to the refrigerant of each indoor unit. It is distributed to a pressure reducer, and then evaporated in each indoor heat exchanger, and then suctioned into a compressor through a low-pressure gas pipe and a refrigerant suction pipe. In this way, all rooms are cooled by each indoor heat exchanger acting as an evaporator.

When heating all rooms at the same time, set the switching valve of the outdoor heat exchanger to the heating state, open the first on-off valve, and open the second on-off valve. By closing the third on-off valve, the refrigerant discharged from the compressor passes through the discharge pipe and the high-pressure gas pipe in order and is distributed to each indoor heat exchanger, where it is condensed and liquefied. The refrigerant is combined in a pipe, then evaporated in an outdoor heat exchanger, and then sucked into a compressor through a refrigerant suction pipe. In this way, all rooms are heated by each indoor heat exchanger acting as a condenser.

In addition, when simultaneously cooling two units and heating one room, the switching valve of the outdoor heat exchanger is set to the heating state, and the first and third on-off valves of the indoor unit to be cooled are closed.
When the second on-off valve is opened, the first on-off valve of the heating indoor unit is opened, and the second and third on-off valves are closed, part of the refrigerant discharged from the compressor flows to the outdoor heat exchanger and the rest The refrigerant flows through the high-pressure gas pipe to the indoor heat exchanger of the heating indoor unit, and is condensed and liquefied in the indoor heat exchanger and outdoor heat exchanger. The refrigerant condensed and liquefied in these heat exchangers is distributed to the refrigerant pressure reducers of each indoor unit via liquid pipes, then evaporated in each indoor heat exchanger, and then transferred to the low-pressure gas pipe and refrigerant suction pipe. and is then sucked into the compressor.

In this way, one room is heated by the indoor heat exchanger acting as a condenser, and two rooms are cooled by the other indoor heat exchanger acting as an evaporator. During such simultaneous heating and cooling operation, the indoor heat exchanger of the indoor unit being cooled is prevented from freezing by closing the second on-off valve and opening the third on-off valve, and any indoor unit is switched from heating to cooling operation. When switching, the high-pressure refrigerant in the indoor heat exchanger flows through the bypass pipe to the liquid pipe, and after the refrigerant pressure decreases, the second on-off valve is opened to prevent refrigerant noise from occurring due to the refrigerant pressure difference.

(f) Example To explain the example of the present invention based on the drawings, (1) is a compressor (2), an outdoor heat exchanger (3), and a gas-liquid separator (4).
and (5a), (5b, and 5c) are indoor units that have indoor heat exchangers (6a), (6b, and 6c), and one end of the outdoor heat exchanger (3) is connected to the compressor (2). A switching valve (9a) is installed between the refrigerant discharge pipe (7) and the refrigerant suction pipe (8).
) (9b), while the outdoor unit (
1) and the indoor units (5a), (5b, and 5c), the high-pressure gas pipe (11) is branch-connected to the refrigerant discharge pipe (7), and the refrigerant suction pipe (8). A low pressure gas pipe (12) branch-connected to the outdoor heat exchanger (
3) with a liquid pipe (13) connected to the other end, and one end of each indoor heat exchanger (6a) (6b) (6c) is connected to a high pressure gas pipe (11) and a low pressure gas pipe (12). Gas branch pipes (14a) (15a), (14b) (15
b) , (14c) (15c), the first on-off valve (16a bar 16b) (16c) and the second on-off valve (17a) (17b) (17c) provided in this branch pipe, and each indoor heat exchanger ( The other end of 6a) (6b bar 6c) is connected to a liquid pipe (
13) Liquid limb tube (19a bar 19b bar 19c) connected to
are provided in the branching units (20a), (20b), and (20c).

(21a) (21b>(21c) is a capillary (22a) (
22b) (22c) are the bypass pipes with throttling resistance, (23a) (23b) (23c) are the second on-off valve (1
7a) With a third on-off valve having a smaller diameter than (17b) (17c), these bypass pipes and the third on-off valve are connected in parallel with the second on-off valves (17a), (17b), and (17c), respectively, and these are also branched. Built into the units (20a) (20b) (20c).

(28) is an auxiliary refrigerant pressure reducer such as an electric expansion valve interposed in the liquid pipe (13).

Next, the driving operation will be explained. When cooling all rooms at the same time, one switching valve (9a) of the outdoor heat exchanger (3) is opened, the other switching valve (9b) is closed, and the branch unit (
20a) (20b) (20c) first on-off valve (16a)
(16b) and (16c) and close the second on-off valve (17
a) By opening (17b) (17C), the compressor (
The refrigerant discharged from the discharge pipe (7) and the switching valve (9a
), the outdoor heat exchanger (3), where it condenses and liquefies, and then flows through the liquid pipe (13) and liquid branch pipes (19a) (19b) (
19c) to each indoor unit (5a) (5b) (5c)
), the refrigerant is distributed to the refrigerant pressure reducers (18a), (18b), and (18c), where the pressure is reduced. After that, each indoor heat exchanger (6
a) After evaporation in (6b) and (6c), the second on-off valves (17a) (17b) (17c), the third on-off valves (23a) (23b) (23c), and the low pressure gas pipe (12), respectively.
The compressor (
2) is inhaled. In this way, all rooms can be cooled simultaneously by each indoor heat exchanger (6a) (6b) (6c) acting as an evaporator.

Conversely, if you want to heat all rooms at the same time, use an outdoor heat exchanger (3)
Close one switching valve (9a) and close the other switching valve (9a).
9b) and branching units (20a) (20b)
(20c) first on-off valves (16a) (16b) (16c
) and open the second on-off valves (17a) (17b) (17
c) and the third on-off valve (23a), the refrigerant discharged from the compressor (2) passes through the discharge pipe (7) and the high-pressure gas pipe (11) in sequence, and then passes through the gas branch pipes (14a) and (14b). )
(14c), the first on-off valve (16a) (1
6b) (16c), indoor heat exchanger (6a) (6b) (
After being condensed and liquefied here, the pressure is reduced by each refrigerant pressure reducer (18a) (18b) (18c), and the liquid pipe (13
), and then evaporated and vaporized in the outdoor heat exchanger (3), followed by the switching valve (9b), suction pipe (8), and gas-liquid separator (
4) is sequentially repeated and sucked into the compressor (2). Each indoor heat exchanger (6a) (6b) acts as a condenser in this way
(6c) All rooms are heated at the same time.

In addition, when simultaneously cooling two units and heating one room, open one switching valve (9a) of the outdoor heat exchanger (3) and close the other switching valve (9b), and branch unit (20) of the indoor unit (5a) (5c)
a) First on-off valve (16a) (16c) in (20c)
) and opens the second on-off valves (17a) (17c) and the third on-off valves (23a) (23c), and the first on-off valve (16b) in the branch unit (20b) of the indoor unit (5b) for heating. At the same time as opening the second on-off valve (17b
) and the third on-off valve (23b), a group of refrigerant discharged from the compressor (2) flows through the discharge pipe (7) and the switching valve (9a).
) in the branch unit (20b) of the indoor unit (5b) that sequentially flows to the outdoor heat exchanger (3) and the remaining refrigerant passes through the high-pressure gas pipe (11) for heating. It flows to the heat exchanger (6b) and is condensed and liquefied in the indoor heat exchanger (6b) and the outdoor heat exchanger (3). The refrigerant that has been condensed and liquefied in these heat exchangers (6b) and (3) passes through the liquid pipe (13) to the indoor unit (5a).
) (5c), the refrigerant is depressurized by the refrigerant pressure reducers (18a) (18c), and then evaporated by the respective indoor heat exchangers (6a) (6c), after which the second on-off valves (17a) (17c) ), the gases are combined in a low-pressure gas pipe (12), passed through a suction pipe (8) and a gas-liquid separator (4>) in sequence, and are sucked into the compressor W! (2).

Indoor heat exchanger (6b) that acts as a condenser in this way
The room is heated, and the room is cooled by the other indoor heat exchangers (6a) (6c), which act as evaporators.

When such simultaneous heating and cooling operation is performed in winter, the indoor heat exchangers (6a) (6c) of the indoor units (5a) (5c) that are cooling the air conditioner are affected because the low pressure refrigerant pressure is affected by the outside temperature.
), the refrigerant pressure in the second on-off valve (17a) (17c) tends to drop below 4kg/can.
and closes the third opening/closing valve (23a) (23a) with a small diameter.
3C) and increases the pressure on the refrigerant outlet side of the indoor heat exchangers (6a) and (6c).
a) (6c) never freezes.

Next, cooling one room and heating one room can be done by operating the auxiliary refrigerant pressure reducer (23).

For example, if the indoor unit (5b) cools the air conditioner and the indoor unit (5b)
5a) (5c), close one switching valve (9a) of the outdoor heat exchanger (3) and close the other switching valve (9a).
b), and closes the first on-off valve (16b) in the branch unit (20b) of the indoor unit (5b) for cooling, and also opens the second on-off valve (17b) and the third on-off valve (23a).
) and indoor units (5a) (5c) that open and heat the room.
The first on-off valves (16a) (16c> in the branch units (20a) and (20c) are opened, and the second on-off valve (17
a) When (17c) and the third on-off valve (23a) (23c) are closed, the refrigerant completely discharged from the compressor (2) is discharged into the discharge pipe (7).
, the first on-off valve (16a) through the high-pressure gas pipe (11)
(16c) and each indoor heat exchanger (6a) (
It is condensed and liquefied in step 6c). The liquefied refrigerant then flows into the liquid pipe (13) through the fully opened refrigerant pressure reducers (18g) (18C), and a part of the liquid refrigerant in this liquid pipe is depressurized by the refrigerant pressure reducer (18b). After that, install the indoor heat exchanger (6b
), and after the remaining liquid refrigerant is depressurized in the auxiliary refrigerant pressure reducer (28), it is evaporated and vaporized in the outdoor heat exchanger (3), respectively.
The compressor (2) passes through the suction pipe (8) and the gas-liquid separator (4) in sequence.
) is inhaled. In this way, one room is heated by the indoor heat exchangers (6a) and (6c) which act as condensers, and the other room is cooled by the other indoor heat exchanger (6b) which acts as an evaporator.

As mentioned above, when the number of rooms to be cooled (cooling capacity) is greater than the number of rooms to be heated (heating capacity), the outdoor heat exchanger (3) is used as a condenser, and conversely, the number of rooms to be heated (heating capacity) is When t) is smaller than the number of rooms to be cooled (cooling capacity), the outdoor heat exchanger (3) can be used as an evaporator to freely cool or heat any room. Heat recovery is performed in each indoor heat exchanger acting as an evaporator and a condenser, which can improve operational efficiency.

Also, during the above-mentioned all-room heating operation, for example, if the indoor unit (5b
) to cooling operation, the first on-off valve (16b
) and the refrigerant pressure reducer (18b) are closed, the bypass pipe (2
1b>, the high-pressure refrigerant flows into the liquid pipe (13) and the refrigerant pressure in the indoor heat exchanger (6b) decreases, after which the second on-off valve (1
By opening 7b), generation of refrigerant noise due to refrigerant pressure difference is prevented.

In addition, these bypass pipes (21a), (21b, and 21c) are used to prevent refrigerant from accumulating in the indoor units when the indoor units (5a, 5b, and 5c) stop cooling or heating operation. It also acts as a refrigerant recovery device.

In the above embodiment, there are three indoor units) - (5a) (5
b) (5c) was used, but even in the case of four or more indoor units with different capacities, simply connect the inter-unit piping (10).
All you have to do is make a branch connection using the two-branch unit, making piping connection work easy.

In addition, in the above embodiment, two-way valves were used as the switching valves (9a) and (9b), but instead of these two-way valves, the switching valves (9a) and (9b)
may be used as one three-way valve.

(G) Effects of the Invention In the present invention, the inter-unit piping that connects the outdoor unit and a plurality of indoor units is composed of three refrigerant pipes: a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe. It is possible to combine any number of units by simply branching and reading them into the inter-unit piping, and the switching valve and the first. By operating the second on-off valve, you can freely select simultaneous cooling and heating operations for multiple indoor units as well as simultaneous cooling and heating operations for any indoor unit. Since the indoor heat exchanger that acts as an evaporator and the indoor heat exchanger that acts as an evaporator are connected in series, efficient operation can be achieved through heat recovery.

Moreover, during such simultaneous heating and cooling operation, the indoor heat exchanger of the indoor unit being cooled is prevented from freezing by closing the second on-off valve and opening the third on-off valve, and any indoor unit is disconnected from heating. When switching to cooling or air-conditioning operation, the high-pressure refrigerant in the indoor heat exchanger flows through the bypass pipe to the liquid pipe, and after the refrigerant pressure drops, the second on-off valve is opened to prevent refrigerant noise caused by the difference in refrigerant pressure. It can be prevented.

[Brief explanation of the drawing]

The drawing is a refrigerant circuit diagram of an air conditioner showing an embodiment of the present invention. (1>...outdoor unit, (2)...compressor,
(3)...Outdoor heat exchanger, (sa>(5b)(5c
)... Indoor unit, (6a) (6b) (6c)...
・Indoor heat exchanger, (7)... Refrigerant discharge pipe, (8)
...Refrigerant suction pipe, (9a) (9b)...Switching valve,
(10)... Inter-unit piping, (11)... High pressure gas pipe, (12)... Low pressure gas pipe, (13)...
- Liquid pipe, (16a) (16b) (16c) = 1st on-off valve, (17a) (17b) (17c)'' - Ice 2 on-off valve, (21g>(21b) (21c)... bypass pipe, (23b) (23c) --- Third on-off valve. (23g)

Claims (1)

[Claims] (1) In an air conditioner in which an outdoor unit having a compressor and an outdoor heat exchanger and multiple indoor units having indoor heat exchangers are connected by inter-unit piping, one end of the outdoor heat exchanger is connected to the compressor. The refrigerant discharge pipe and the refrigerant suction pipe are branched and connected via switching valves, while the inter-unit piping is connected to the high pressure gas pipe connected to the discharge pipe, the low pressure gas pipe connected to the suction pipe, and the outdoor heat pipe. a liquid pipe connected to the other end of the exchanger, one end of each indoor heat exchanger is connected to the high pressure gas pipe with a first on-off valve, and the low-pressure gas pipe with a second on-off valve, respectively. The liquid pipe is connected via a refrigerant pressure reducer, and a bypass pipe and/or a third on-off valve having a refrigerant throttling resistance is connected in parallel with the second on-off valve. Air conditioner.