JP3249246B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a plurality of outdoor units, wherein the number of operating these outdoor units is controlled according to the air conditioning load.

[0002]

2. Description of the Related Art In general, there is known an air conditioner in which a plurality of outdoor units are connected in parallel to a pipe between units extending from an indoor unit, and the number of these outdoor units to be operated is controlled in accordance with the air conditioning load in the room. JP-A-1-247
967).

[0003]

The outline of this type of air conditioner is shown in FIG. 5, and it has been found that there are the following problems particularly during the heating operation. That is, for example, the outdoor unit 91
Is stopped, all the refrigerant discharged from the outdoor unit 92 during operation flows toward the indoor unit 90 as shown by the solid line arrow.

[0004] Therefore, the refrigerant accumulates (falls down) in a part 93 (gas pipe) of the unit-to-unit pipe connecting the stopped outdoor unit 91 and the operating outdoor unit 92, and
It became a state of lack of refrigerant (gas shortage), and the desired heating capacity could not be maintained. In particular, when the length L of the gas pipe 93 is long and / or the outside air temperature is low, the amount of refrigerant accumulated in the gas pipe 93 increases, and the occurrence of the above problem becomes extremely large.

As an example, for example, an outdoor unit 91,
When the total horsepower of 92 and 93 is 10 hp, the gas pipe 93 is generally called "inch 1 minute", and the liquid refrigerant is laid down per unit length at this time. The quantity is: [(25.4 mm × 9 / 8-2 mm) ÷ 2] ² × π ×
1.2 × 10 ⁶ kg / mm ³ = 0.67 kg / m where 25.4 mm = 1 inch 9/8 = 1 + (1/8) = “1 inch + ／ inch”
= Inch 1 minute 2 mm = wall thickness of refrigerant pipe × 2 1.2 × 10 ⁶ kg / mm ³ = density of liquid refrigerant at 20 ° C outside temperature 0.66 kg / m of liquid refrigerant is laid down When the gas pipe 93 is 10 m long, it is undeniable that a large amount of the liquid refrigerant of 6.7 kg stagnates and the above-described state of the refrigerant shortage (gas shortage) occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the accumulation of refrigerant in inter-unit piping connecting a plurality of outdoor units, and to reduce the possibility of shortage of refrigerant during low-capacity operation.

[0007]

In order to achieve this object, the present invention relates to a method for reducing the load of air conditioning in a room, for example, when the operation of one outdoor unit is stopped, in the gas pipe of the stopped outdoor unit and the stop. A bypass pipe is provided for guiding the refrigerant in the unit-to-unit pipe connected to the outdoor unit to the outdoor unit in operation via the liquid pipe of the outdoor unit.

The bypass pipe is provided with a valve which is opened when the operation is stopped.

[0009]

In the outdoor unit whose operation has been stopped because the air conditioning load in the room has been reduced, the refrigerant in the gas pipe of the outdoor unit and in the piping between the units is led to the liquid pipe of the outdoor unit via the bypass pipe. Then, the refrigerant guided to the liquid pipe is sucked into the outdoor unit during operation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the air conditioner according to the present invention will be described below.
Will be described with reference to the drawings. Figure 1 shows a so-called multi-type
3 shows an air conditioner and three outdoor units 1 ₁,
1_Two, 1_ThreeAnd a plurality of indoor units 3₁, 3_Two, ... 3
_nAnd an inter-unit pipe 5 connecting these.

[0011] The outdoor unit 1 ₁ illustrating its configuration as an example, the outdoor unit 1 _1, the accumulator 1
0, the compressor 11, the oil separator 12, the check valve 49,
It has a four-way valve 13, an outdoor heat exchanger 14, and an outdoor electric expansion valve 15, which are connected by a refrigerant pipe. The oil separator 12 separates oil in the refrigerant discharged from the compressor 11, and the separated oil is returned to the compressor 11 through the return pipe 21. The return pipe 21 is provided with a valve 23 for adjusting the amount of oil. Check valve 4 above
9 at the time of operation stop of the outdoor unit 1 _1, the refrigerant is four-way valve 1
3 prevents the oil from flowing back to the oil separator 12.

Reference numeral 24 denotes a bypass pipe which is a feature of the present invention.
Gas pipe 25 extending from four-way valve 13 and outdoor electric expansion valve 1
5 and a liquid pipe 26 extending from the liquid pipe 5. The bypass pipe 24 is provided with a check valve 27 and a capillary tube 28 (for example, 0.8 mm × 1000 mm) as shown in FIG. The check valve 27 is made of an open state only when it stops the outdoor unit 1 ₁ The check valve 27 is provided. The configuration of the remaining two of the outdoor unit 1 _2, 1 ₃ are the configuration substantially the same as the outdoor unit 1 _1, description is omitted.

The above-mentioned interunit piping 5 is a gas side piping 5
a and a liquid side pipe 5b. Then, the gas-side pipe 5a the gas pipe 25 of the outdoor unit 1 _1, the liquid side pipe 5b are respectively connected to the liquid pipe 26 of the outdoor unit 1 _1. Incidentally, the outdoor units ₁ 1, 1 _2, 1 ₃ of the return pipe 21 is connected by a balance pipe 29. And
These three outdoor unit 1 _1, 1 _2, 1 ₃ and a plurality of indoor units 3 _1, 3 ₂ are connected by inter-unit pipe 5 in parallel with ... 3 _n. As described later, the outdoor unit 1 ₁ is a variable capacity units, the outdoor unit 1 _2, 1 ₃ is the ability constant unit.

[0014] Next, when the indoor unit 3 ₁ illustrating its configuration as an example, the indoor unit 3 ₁ is provided with the indoor heat exchanger 34, an indoor electric expansion valve 35, which are connected by the refrigerant pipe. Furthermore, the indoor unit 3 _1,
A sensor 37 capable of detecting the indoor air-conditioning load is provided, and the value detected by the sensor 37 is controlled by the controller 51, respectively.
Is input to Here, the controller 51 in the outdoor unit 1 ₁ in accordance with the total value seeking sum of these input values, 1 _2, 1 ₃ throat compressor A, B, C, determines whether to operate the D , And sends the signal to these compressors.

Here, the air conditioning capacity of the air conditioner is 2
When the power is set to 0 hp, referring to FIG.
The _1, 0-6 horsepower compressor 11 capacity compressor A and ability to be changed is composed of a compressor and B constant type 4 horsepower provided, the outdoor unit 1 _2, capacity 5 hp An outdoor unit 1 is provided with a compressor comprising a fixed type compressor C.
₃ is provided with a compressor composed of a compressor D having a fixed capacity of 5 horsepower.

[0016] The controller 51 performs the total load of the air conditioner compressor A, as shown in FIG. 2, B, C, the operation control of the D (outdoor unit ₁ 1, 1 _2, 1 _3). That is, when the air conditioning load is 17 horsepower from 20 hp, all of the outdoor units 1 _1, 1 _2, 1 ₃ is operated. Here, the compressor A of the outdoor unit 1 ₁ is its ability is operated to adjust from 3 hp to 6 hp.

[0017] Similarly all of the outdoor unit when the 10 horsepower air-conditioning load is from 16 horsepower 1 _1, 1 _2, 1 ₃ but is operated, operation of the compressor B of the outdoor unit 1 ₁ is a compressor A stop The driver adjusts his ability from 0 hp to 6 hp to drive. As described above, when all the outdoor units are operating (heating), the refrigerant flows as indicated by solid arrows in FIG. Therefore, the refrigerant always flows in the inter-unit pipe 5, and the refrigerant lays down (accumulates) in the inter-unit pipe 5.
Never.

Meanwhile, when the air conditioning load is 7 horsepower from 9 horsepower, stops the operation only the outdoor unit 1 _2, also stops the operation of the compressor B of the outdoor unit 1 _1, the compressor A is its ability 2 Drive up to 4 horsepower. Furthermore,
When the air conditioning load is between 6 hp and 0 hp, the outdoor unit 1
Only the compressor A in ₁ is operated by adjusting to 0 to 6 hp.

[0019] In this manner the air-conditioning load is lowered, although the outdoor unit 1 ₁ continues the operation, the outdoor unit 1 _2, 1 ₃ operation is stopped. In this case, indicates the flow of the refrigerant of the inter-unit pipe 60 of the continuously operated is the outdoor unit 1 ₁ (1 ₃₎ with respect to counter the indoor unit side (i.e. operation will lead to the outdoor unit 1 ₂ is stopped) FIG. 4 shows the result.

[0020] In FIG 4, the gas-side pipe 61 connected to the outdoor unit 1 ₂ in the shutdown is connected to the gas side pipe 5a extending from the outdoor unit 1 _3, 1 ₁ in operation, yet during this outage Outdoor unit gas pipe 6
1 is connected to the outdoor unit 1 ₃ of the liquid pipe 5b during operation via the bypass pipe 24 and the outdoor unit 1 in _two liquid pipes 62 in the shutdown.

[0021] Therefore, the gas refrigerant discharged from the outdoor unit 1 ₃ in operation although flows to the indoor unit 3 ₁ side, part of the refrigerant in the outdoor unit 1 ₂ is stopped as indicated by broken line arrows in FIG. 4 flow, a check valve 27 (which is opened by the pressure of the refrigerant), the capillary tube 28 via the bypass pipe 24 provided back to the outdoor unit 1 ₃ in operation. Thus the part of the refrigerant discharged from the outdoor unit 1 ₃ in operation pouring into the outdoor unit 1 ₂ is stopped, it is so arranged back again to the outdoor unit 1 ₃ in operation via the bypass pipe 24, there is no possibility that the refrigerant be laid up for a long time in the inter-unit pipe 60 connected to the outdoor unit 1 ₂ is stopped.

Each of the above-described flows of the refrigerant has been described for heating. During the cooling operation, any of the outdoor unit 1 _1, 1 _2, 1 ₃ of the four-way valve 13 is also the refrigerant flow by a broken line state in the direction opposite to the solid arrow in FIG. 1 and FIG. The cooling in operation, the check valve 27 of the bypass pipe 24 of the outdoor unit during shutdown by the high-pressure refrigerant discharged from the outdoor unit 1 ₃ of the liquid pipe 26 during operation (e.g., the outdoor unit 1 ₂₎ is closed and refrigerant gas side pipe 61 from the outdoor unit 1 ₂ in the stop is sucked to the outdoor unit 1 ₃ in operation. For this reason, the refrigerant is less likely to stagnate in the inter-unit piping 60 during the cooling operation.

[0023] In FIG. 3, 70, 71, 72 is a valve provided in the outdoor unit 1 _1. The bypass pipe 24 described above may be provided so as to connect the gas-side pipe 5a and the liquid-side pipe 5b as shown by the one-dot chain line 80 in FIG.

[0024]

As described above, according to the present invention, the bypass pipe for guiding the refrigerant in the gas pipe of the stopped outdoor unit to the operating outdoor unit via the liquid pipe of the outdoor unit is provided. No refrigerant pool is generated in the unit-to-unit piping near the closed outdoor unit.

Further, since the bypass pipe is provided with a valve which is opened (returned) only when the refrigerant is stopped, the refrigerant surely flows in the bypass pipe only when it is stopped. For these reasons, normal operation can be maintained without running out of gas when the air conditioning load decreases.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing an operation state of a compressor in the air-conditioning apparatus shown in FIG.

FIG. 3 is an explanatory view showing a bypass pipe of the outdoor unit shown in FIG.

FIG. 4 is an explanatory diagram of piping between units of the air-conditioning apparatus shown in FIG. 1;

FIG. 5 is an explanatory diagram of a conventional air conditioner.

[Explanation of symbols]

1 _1, 1 _2, 1 ₃ outdoor unit 3 _1, 3 ₂ (3 _n) indoor units 5 unit pipes 24 bypass pipe 25 a gas pipe 26 liquid pipe 27 valve

Claims (2)

(57) [Claims] An indoor unit and a plurality of outdoor units are provided, and a gas pipe and a liquid pipe of each outdoor unit are connected in parallel to an inter-unit pipe extending from the indoor unit, and these are connected in accordance with the air conditioning load in the room. In an air conditioner in which the number of operating outdoor units is controlled, the gas pipes and liquid pipes of these outdoor units transfer refrigerant in the gas pipes and pipes between the units to the liquid pipes when the operation of the outdoor units is stopped. An air conditioner characterized by being connected by a bypass pipe for flowing. 2. An indoor unit and a plurality of outdoor units, wherein a gas pipe and a liquid pipe of each indoor unit are connected in parallel to a unit-to-unit pipe extending from the indoor unit, and these are connected in accordance with the indoor air conditioning load. In an air conditioner in which the number of operating outdoor units is controlled, a gas pipe and a liquid pipe of these outdoor units are connected by a bypass pipe, and a valve that is opened when the operation of the outdoor unit is stopped is provided in the bypass pipe. An air conditioner, characterized in that: