JPH07218034A - Air-conditioning device - Google Patents

Abstract

PURPOSE:To divide the pressure of a high pressure refrigerant of a freezing cycle into a plurality of stages as a work to interconnect a plurality of outdoor units in parallel is simplified. CONSTITUTION:A valve 14b to prevent inflow of a high pressure gas refrigerant, delivered from a compressor 8a of an outdoor unit 3a, having low freezing capacity, of a plurality of indoor units 3a and 3b having different freezing capacity, to the delivery pipe of a compressor 8b of the indoor unit 3b having high freezing capacity through a high pressure gas pipe 5 is arranged at the outdoor unit 3b having high freezing capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner for simultaneously cooling or heating all of a plurality of rooms and simultaneously cooling an arbitrary room and heating another room.

[0002]

2. Description of the Related Art At the same time, there is JP-A-5-1862 as an air conditioner capable of cooling an arbitrary one of a plurality of rooms and heating another room (simultaneous cooling and heating operation).
According to this proposal, a plurality of indoor units and a plurality of outdoor units having a built-in compressor are connected by a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe, and an opening / closing valve is provided in this high-pressure gas pipe. It is a thing.

By closing the on-off valve, the high-pressure gas refrigerant discharged from the respective outdoor units is prevented from being mixed with each other, and the pressure state of the high-pressure refrigerant in the refrigeration cycle is set to two stages. That is, the pressure of the high-pressure gas refrigerant is maintained at an appropriate value for each indoor unit, and the operating efficiency is improved.

[0004]

In the air conditioner having such a structure, the opening / closing valve is provided in the high pressure gas pipe, that is, outside the outdoor unit. Therefore, this on-off valve must be installed on the high-pressure gas pipe when connecting the pipes of the air conditioner, which complicates the connecting work.
Further, a control signal (electrical signal) for opening / closing the opening / closing valve is required, and wiring work for sending the electrical signal at the time of the above-mentioned connection is also required.

Therefore, an object of the present invention is to make it possible to easily make the high-pressure refrigerant in the refrigeration cycle in two stages without the need to install an on-off valve during the above-mentioned connection work.

[0006]

In order to achieve this object, a first aspect of the present invention is directed to a high pressure gas refrigerant discharged from a compressor of an outdoor unit having a small refrigerating capacity among a plurality of outdoor units having different refrigerating capacity. A valve for preventing the inflow of the compressor of the outdoor unit having a large refrigerating capacity from the gas pipe is provided in the outdoor unit having a large refrigerating capacity. A second aspect of the present invention includes a plurality of outdoor units, one outdoor unit and the other outdoor unit whose operation is stopped and started preferentially over the operation of the one outdoor unit according to the increase or decrease of the air conditioning load. A valve for preventing the high-pressure gas refrigerant discharged from the compressor of the one outdoor unit from flowing into the discharge pipe of the compressor of the other outdoor unit is provided in the other outdoor unit. Is.

[0007]

According to the first aspect of the invention, the high-pressure refrigerant discharged from the compressor of the outdoor unit having a small refrigerating capacity is acted by the valve built in the outdoor unit having a large refrigerating capacity, so that the outdoor unit having a large refrigerating capacity is obtained. It does not mix with the high-pressure refrigerant discharged from the compressor.

According to the second aspect of the present invention, in the outdoor unit in which the operation is preferentially started / stopped among the plurality of outdoor units according to the increase / decrease of the air conditioning load, the other outdoor unit in operation when the outdoor unit is stopped. The refrigerant discharged from the unit is not introduced into the outdoor unit that is stopped.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is an air conditioner, which comprises a plurality of indoor units 2a, 2b, 2c, a plurality of outdoor units 3a, 3b, and both indoor and outdoor units 2a, 2b, 2
It is composed of an inter-unit pipe 4 connecting c, 3a and 3b. The inter-unit pipe 4 is composed of a high pressure gas pipe 5, a low pressure gas pipe 6, and a liquid pipe 7.

The first outdoor unit 3a includes a three horsepower inverter rotary compressor 8a and an outdoor heat exchanger 12a.
And are built in. And the suction pipe 9a of the compressor 8a
Is connected to the low-pressure gas pipe 6, and the discharge pipe 10a of the compressor 8a is connected to one end of the outdoor heat exchanger 12a via the first opening / closing valve 11a. Further, one end of the outdoor heat exchanger 12a is connected to the low pressure gas pipe 6 via the second opening / closing valve 13a. Further, the other end of the outdoor heat exchanger 12a is connected to the liquid pipe 7 via the outdoor electric valve 13a. Reference numeral 14a denotes a valve (hereinafter referred to as "check valve") which is a feature of the present invention, and is a pipe 15 that connects the discharge pipe 10a of the compressor 8a and the high pressure gas pipe 5 to each other.
It is provided in a. In this embodiment, the check valve 14 is provided in each of the two outdoor units 3a and 3b.
Although a and 14b are provided, they may be provided only in the second outdoor unit 3b. The reason will be described later. On the other hand, in the second outdoor unit 3b, substantially the same devices as the first outdoor unit 3a are housed, and the respective devices are connected by similar valves. However, the compressor 8b is a 6 horsepower rated rotary type, and accordingly, the outdoor heat exchanger 12b
Is also set to be larger than the outdoor heat exchanger 12b of the first outdoor unit 3a. That is, the first outdoor unit 3a
The outdoor heat exchanger 12a has a power of about 3 horsepower, and the outdoor heat exchanger 12b of the second outdoor unit 3b has a power of about 6 horsepower.

On the other hand, each indoor unit 2a, 2b, 2c contains an indoor heat exchanger 16a, 16b, 16c, and one end side cooling pipe 17a, 17 of this indoor heat exchanger.
b and 17c are connected to the low pressure gas pipe 6 via the third on-off valves 18a, 18b and 18c, and the heating pipes 19a, 19b and 19c are connected to the high pressure gas pipe 5 via the fourth on-off valves 20a, 20b and 20c.
Connected to each. In addition, this indoor heat exchanger 16a, 1
The other end side of 6b, 16c has indoor electric valves 21a, 21b, 2
It is connected to the liquid pipe 7 via 1c.

The air conditioner 1 has the following four operating states. When the indoor units 2a, 2b, 2c are all in the cooling operation, and when the indoor units 2a, 2b, 2c are all in the heating operation. One indoor unit 2a, 2b
Is the cooling operation, the other indoor unit 2c is the heating operation, and the heating load is larger than the cooling load. One indoor unit 2a, 2b is in the cooling operation, the other indoor unit 2c is in the heating operation, and the cooling load is larger than the heating load.

The present invention is particularly effective in the above case.
First, when all the indoor units are in the cooling operation, the compressors 8a and 8b are operated and the open / close states of various on-off valves are set to the states shown in FIG. During this operation, the valve opening degrees of the outdoor electric valves 30a, 30b are set to a substantially fully opened state, and the indoor electric valves 21a,
The valve opening degrees of 21b and 21c are the same as the indoor electric valves 21a and 2c.
Indoor units 2a, 2b, 2 accommodating 1b, 21c
It is controlled according to the cooling load of c. As a result, the outdoor heat exchangers 12a and 12b act as condensers, and the indoor heat exchangers 16a, 16b and 16c act as evaporators, and each room is cooled. During this cooling only operation, when the cooling load is large (9 horsepower), both outdoor units 3a and 3b are operated. Then, the operating capacity of the first outdoor unit 3a is sequentially reduced from 3 horsepower in accordance with the decrease in the cooling load. When the cooling load decreases to 6 horsepower, the operation of the first outdoor unit (variable capacity unit) 3a is stopped with priority over the operation of the second outdoor unit (constant capacity unit) 3b. After that, when the cooling capacity becomes 3 horsepower or less, the first outdoor unit 3a is operated and the second outdoor unit 3b is stopped.

On the other hand, when all the indoor units are in the heating operation, the compressors 8a and 8b are operated, and the open / close states of various on-off valves are set to the states shown in FIG. 2 so that the refrigerant flows as indicated by solid arrows. During this operation, the indoor electric valve 21
The valve openings of a, 21b and 21c are set to a substantially fully opened state, and the valve openings of the outdoor electric valves 30a and 30b are controlled according to the heating load of the indoor unit. As a result, the indoor heat exchangers 16a, 16b, 16c act as condensers, and the outdoor heat exchangers 12a, 12b act as evaporators, thereby heating each room. During this heating only operation, when the heating load is large (9 horsepower), both outdoor units 3a and 3b are operated. Then, the operating capacity of the first outdoor unit 3a is sequentially reduced from 3 horsepower in accordance with the decrease in the heating load. When the heating load decreases to 6 horsepower, the operation of the first outdoor unit (variable capacity unit) 3a is stopped with priority over the operation of the second outdoor unit (constant capacity unit) 3b. After that, when the heating capacity becomes 3 horsepower or less, the first outdoor unit 3a is operated and the second outdoor unit 3b is stopped. The operation control of the outdoor unit according to the variation of the heating load is the same as that of the variation of the cooling load.

Next, when the heating load is larger than the cooling load and the outdoor heat exchangers 12a and 12b act as evaporators (mainly for heating), various on-off valves are set in the state shown in FIG. Shed like. In this case, the refrigerant discharged from each of the compressors 8a and 8b merges in the high-pressure gas pipe 5, and the indoor units 2a and 2b that perform the heating operation.
To the indoor heat exchangers 16a and 16b. afterwards,
The refrigerant flows into the liquid pipe 7 through the indoor electric valves 21a and 21b which are almost fully opened, and the outdoor heat exchange of the outdoor unit 3b is performed via the outdoor electric valve 13b and the indoor electric valve 21c whose opening degrees are respectively controlled. It flows into the unit 12b and the indoor heat exchanger 16c of the indoor unit 2c. And low pressure gas pipe 6
And is returned to the respective compressors 8a and 8b via. During such operation, the refrigerant does not flow into the outdoor heat exchanger 12a of the outdoor unit 3a by closing the outdoor electric valve 30a. From a different perspective on this phenomenon, in the outdoor unit 3b,
Heating load of indoor units 2a and 2b and indoor unit 2c
That is, it suffices to flow only the difference of the cooling load of the above to the outdoor unit 3b. Specifically, since the heating load is 9 hp and the cooling load is 3 hp, 6 (9-3) hp of refrigerant is used. It is poured into the outdoor heat exchanger 12b to perform the evaporation action.

Next, when the cooling load is larger than the heating load and the outdoor heat exchanger 12b acts as a condenser (mainly for cooling), the various open / close valves are set to the state shown in FIG. To shed. In this case, the refrigerant discharged from the first outdoor unit 3a causes the indoor heat exchanger 16 of the indoor unit 2c to perform the heating operation via the high pressure gas pipe 5.
The refrigerant discharged from the second outdoor unit 3b while flowing into the second outdoor unit 3b does not flow into the high pressure gas pipe 5 by the action of the check valve 14b, and the outdoor heat exchanger 12 of the second outdoor unit 3b
flow into b. After that, the refrigerant from the outdoor unit 3b and the indoor unit 2c in the heating operation merges in the liquid pipe 7, and then flows into the two indoor units 2a and 2b in the cooling operation in parallel, and then the low pressure gas pipe. Two compressors 8 through 6
a, 8b.

Here, as described above, the refrigerant discharged from the first outdoor unit 3a, that is, the outdoor unit 3a having a small refrigerating capacity, and the refrigerant discharged from the second outdoor unit 3b, that is, the unit having a large refrigerating capacity 3b. Since the check valve 14b prevents mixing, the pressure of the high pressure refrigerant at the point A and the pressure of the high pressure refrigerant at the point B in FIG. 4 can be changed. Therefore, for example, when the heating load of the indoor unit 2c during the heating operation increases, the capacity of the compressor 8a is increased. Along with this, the pressure of the high-pressure refrigerant discharged from the compressor 8a increases, but the increased refrigerant does not flow into the outdoor heat exchanger 12b by the action of the check valve 14b, and all the indoor units under heating operation. It flows into the indoor heat exchanger 16c of 2c. Therefore, the refrigerant pressure is increased only in the high pressure gas pipe 5 connected to the indoor unit 2c during the heating operation, and it is not necessary to increase the refrigerant pressure in the high pressure side pipe connected to the outdoor heat exchanger 12b. (Compressor) The overall coefficient of performance can be improved. Moreover, the lower the outside air temperature, the lower the refrigerant pressure at point B of the outdoor unit 3b, which is causing the refrigerant to flow to the outdoor heat exchanger 12b, becomes lower than the refrigerant pressure at point A of the high-pressure gas pipe 5. Therefore, the lower the outside air temperature, the more the above-mentioned coefficient of performance can be improved.

The check valve 14b also functions to prevent reverse rotation of the compressor 8b. That is, it is also a check valve 14b for preventing the refrigerant from the high-pressure gas pipe 5 from flowing back to the compressor 8b when the operation of the compressor 8b is stopped. Further, when the air conditioning load is reduced and the operation of the first outdoor unit 3b is stopped and the operation of the second outdoor unit 3b is continued, the check valve 14a acts on the first outdoor unit 3a. It is possible to prevent the high-pressure refrigerant from flowing in and prevent the occurrence of gas shortage.

Since such check valves 14a and 14b are housed in the respective outdoor units 3a and 3b, it is not necessary to specially attach such valves when connecting the units by piping. In the above embodiment, the first outdoor unit 3a has the variable capacity compressor 8a built therein, while the second outdoor unit 3b has the constant capacity compressor 8b.
And the refrigerating capacity of the second outdoor unit 3b is set to be larger than that of the first outdoor unit 3a. However, which of the outdoor units 3a, 3b
Also, a variable capacity compressor may be incorporated. Further, since the check valve 14a built in the first outdoor unit is for preventing the reverse rotation of the variable capacity compressor 8a, in the case of a compressor (reciprocating type) which does not reverse when the operation is stopped, This check valve 14a is not necessary.

[0020]

As described above, according to the first aspect of the present invention, the high pressure gas refrigerant discharged from the compressor of the outdoor unit having a small refrigerating capacity is supplied to the compressor of the outdoor unit having a large refrigerating capacity through the high pressure gas pipe. Since the valve for preventing the gas from flowing into the discharge pipe is provided in the outdoor unit having a large refrigerating capacity, it is possible to save the trouble of providing such a valve when connecting the outdoor units to each other. This can facilitate simplification of the piping connection work between the outdoor units.

According to a second aspect of the present invention, the plurality of outdoor units are connected to one outdoor unit and the other outdoor unit whose operation is started and stopped preferentially over the operation of the one outdoor unit in accordance with increase or decrease of the air conditioning load. And a valve for preventing high-pressure gas refrigerant discharged from the compressor of the one outdoor unit from flowing into the discharge pipe of the compressor of the other outdoor unit. Therefore, the refrigerant from the operating outdoor unit can be prevented from flowing into the stopped outdoor unit. As a result, it is possible to reduce the risk that the refrigerant will flow into the outdoor unit that is stopped to cause a shortage of the refrigerant.

Moreover, by incorporating such a valve in the outdoor unit, it is possible to prevent reverse rotation when the compressor of the outdoor unit is stopped.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner of the present invention.

FIG. 2 is a refrigerant circuit diagram showing a refrigerant flow during full heating.

FIG. 3 is a refrigerant circuit diagram showing a refrigerant flow when heating is mainly performed.

FIG. 4 is a refrigerant circuit diagram showing a refrigerant flow when cooling is mainly performed.

[Explanation of symbols]

 1 Air conditioner 2a, 2b, 2c Indoor unit 3a, 3b Outdoor unit 5 High pressure gas pipe 6 Low pressure gas pipe 7 Liquid pipe 14a, 14b (check) valve

Claims (2)

[Claims] 1. An air conditioner in which a plurality of outdoor units each having a built-in compressor and different refrigerating capacity and a plurality of indoor units are connected by a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe, A valve that prevents the high-pressure gas refrigerant discharged from the compressor of the outdoor unit having a small refrigerating capacity from flowing into the discharge pipe of the compressor of the outdoor unit having a large refrigerating capacity through the high-pressure gas pipe is An air conditioner provided in a large outdoor unit. 2. An air conditioner in which a plurality of outdoor units each having a built-in compressor and a plurality of indoor units are connected by a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe, wherein the outdoor unit is one of High pressure discharged from the compressor of the outdoor unit and the other outdoor unit whose operation is started and stopped with priority over the operation of the one outdoor unit according to the increase or decrease of the air conditioning load. An air conditioner characterized in that a valve for preventing gas refrigerant from flowing into a discharge pipe of a compressor of the other outdoor unit is provided in the other outdoor unit.