JP2983782B2 - 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 in which a plurality of outdoor units are connected in parallel to piping between units extending from an indoor unit.

[0002]

2. Description of the Related Art In general, a plurality of indoor units are arranged in parallel, and a plurality of outdoor units including a compressor, an outdoor heat exchanger, etc. are connected in parallel to piping between units connected to each indoor unit. A connected multi-type air conditioner is known (for example, see Japanese Patent Laid-Open No. 2-85656).
Reference).

[0003] This type of multi-type air conditioner includes a plurality of outdoor units.
There is an advantage that a large-capacity system of the device can be realized according to the air-conditioning load.

[0004]

However, when a plurality of outdoor units are combined, the capacity of the apparatus becomes large, so that it is conceivable that the amount of refrigerant used increases. When the usage amount of the refrigerant increases in this way, for example, when the air conditioning load is small, the refrigerant becomes excessive. When a receiver for storing excess refrigerant is provided in consideration of this,
If the liquid refrigerant accumulates in the receiver when the air conditioning load is large, it is conceivable that the air conditioner (system) will be short of the refrigerant.

An object of the present invention is to reduce the amount of refrigerant as an air conditioner (system) and reduce the cost of the device.

[0006]

In order to achieve this object, the present invention relates to a method of connecting a plurality of outdoor units in parallel to an inter-unit pipe extending from an indoor unit, and connecting these outdoor units to one of the outdoor units. When, according to the decrease of the air-conditioning load is constituted by the other of the outdoor unit operated before is stopped than the outdoor unit of the one, receiver capacity of hand of which is housed in the outdoor unit of the other side Kushida smaller than the capacity of the receiver housed in the outdoor unit, or is obtained so as to place the receiver on only one outdoor unit.

A variable capacity compressor capable of variably controlling the capacity in accordance with the air conditioning load is housed in one outdoor unit, and a fixed capacity compressor is housed in the other outdoor unit. Things.

[0008]

When the air-conditioning load is reduced, the other outdoor unit having a small capacity of the receiver or having no receiver is stopped first, so that it is difficult for the refrigerant to accumulate in the other outdoor unit, and the predetermined amount of refrigerant is reduced. Is introduced into one outdoor unit.

[0009]

FIG. 1 shows an outdoor unit 1 and 2 and an indoor unit 3 and 4, respectively. Reference numeral 5 denotes a unit-to-unit pipe extending from these indoor units, which comprises a gas pipe 6 and a liquid pipe 7.
Are connected in parallel to the interunit piping 5. A balance tube 8 connects the outdoor units 1 and 2 to each other.

The indoor units 3 and 4 include an indoor heat exchanger 9.
And an indoor electric expansion valve (indoor mechanical valve) 10. The opening degree of the indoor mechanical valve 10 is adjusted during both the cooling operation and the heating operation. Here, one outdoor unit 1 houses a variable capacity compressor (described later) that can variably control the capacity according to the air conditioning load.

The other outdoor unit 2 houses a compressor of a fixed capacity (to be described later). When the air-conditioning load (the sum of the air-conditioning loads in the room where all the indoor units 3 and 4 are operated and / or the indoor units 3 and 4 are arranged) is the maximum, the operating capacity of the compressor of one of the outdoor units 1 Is operated while the other outdoor unit 2 is operated. Next, when the air-conditioning load is reduced, the operating capacity of the compressor of one of the outdoor units 1 is reduced in accordance with the reduction. When the air conditioning load becomes equal to or less than a predetermined value (air conditioning capacity of the other outdoor unit 2), the operation of the other outdoor unit 2 is stopped before the operation of the one outdoor unit 1. Here, the operation of the compressor of one of the outdoor units 1 is adjusted according to the air conditioning load.
In this way, by combining the capacity control of the compressor of one outdoor unit 1 and the operation control (ON-OFF) of the other outdoor unit 2, linear capacity control according to the air conditioning load is performed.

FIG. 2 is a refrigerant circuit diagram of one of the outdoor units 1, wherein reference numeral 20 denotes a rotary compressor whose capacity can be variably controlled according to the indoor air-conditioning load, and reference numeral 21 denotes a discharge pipe 22 of the compressor 20. Oil separator 23, this oil separator 21
An oil return pipe for returning oil in the compressor to the compressor. An outlet pipe 24 is connected to a suction pipe 25 of the compressor 20, and an inlet side is branched and connected to a side of the oil separator 21. It is divided into an oil return pipe 26 and a second oil return pipe 27 connected to the bottom of the oil separator 21. The second oil return pipe 27 is provided with a balance valve 28, and is connected to the balance pipe 8. Reference numeral 29 denotes a four-way valve, which is set to a solid line state during the cooling operation and set to a broken line state during the heating and defrosting operation. 3
Numeral 0 denotes a defrosting pipe, which sends the high-temperature refrigerant from the oil separator 21 to the outdoor heat exchanger 32 by opening the control valve 31 during the defrosting operation. An outdoor electric expansion valve (outdoor mechanical valve) 33 is set to a fully open state during a cooling operation, and its opening is adjusted during a heating operation. Reference numeral 34 denotes a liquid-side pipe connected to the liquid pipe 7 of the inter-unit pipe 5. The liquid-side pipe 34 is provided with a liquid injection pipe 35 connected to the suction pipe 25 and a liquid receiver 36. 37 is a discharge pipe, one end of which is above the liquid receiver 36 and the other end of which is the oil separator 21.
And a four-way valve 29 connected to a high-pressure pipe 38. 3
Reference numeral 9 denotes a bypass (power save) pipe for returning a part of the refrigerant discharged from the oil separator 21 to the gas-liquid separator 40.

Reference numeral 41 denotes an auxiliary pipe. The high pressure refrigerant from the oil separator 21 is introduced into the auxiliary pipe 41 by opening the control valve 42, and the oil in the balance pipe 8 and the second oil return pipe 27 is removed from the compressor 20. It is sent to. FIG. 3 is a refrigerant circuit diagram of the other outdoor unit 2, and the same components as those shown in FIG. 2 are denoted by the same reference numerals and description thereof is omitted. Reference numeral 50 denotes a scroll compressor of a fixed capacity type, which is generally called an "internal low pressure type".
Outlet pipe 24 is directly connected to the scroll compressor 50. Here, the difference from the outdoor unit 1 shown in FIG. 2 is that the other outdoor unit 2 is not provided with a liquid receiver. Of course, since this liquid receiver is not provided, no discharge pipe is provided.

When the outdoor units 1 and 2 having such a configuration are connected as shown in FIG. 1 to perform a cooling operation, for example, the four-way valve 29 is set to a solid line state with reference to FIGS. . By operating both compressors 1 and 2, the cold soot flows as indicated by the solid arrow. The oil separated by the oil separator is usually returned to the respective compressors 20 and 50 via the first oil return pipe 26 and the outlet pipe 24 as shown by the dashed arrows. In addition, for example, the compressor 2 of the one outdoor unit 1
When the oil amount of “0” becomes equal to or less than the predetermined amount, the oil in the oil separator 21 of the other outdoor unit 2 is guided to the compressor 20 as shown by the dashed line arrow.

Here, when the cooling load is the maximum, the compressor 20 of one of the outdoor units 1 is operated at the maximum capacity, and the operation of the other outdoor unit 2 is also continued. As the cooling load decreases, the capacity of the compressor 20 of the one outdoor unit 1 also decreases. When the cooling load becomes equal to or less than a predetermined value (the capacity of the compressor 50 of the other outdoor unit 2), the operation of the other outdoor unit 2 is stopped, and the operation is switched to the operation of only the one outdoor unit 1. At the same time, the operation of the compressor 20 is adjusted according to the cooling load.

At this time, regarding the refrigerant in the other outdoor unit 2 which is stopped, the gas refrigerant in the gas-liquid separator 40 is drawn into the gas pipe 6 via the four-way valve 29 and the outdoor mechanical valve 33. By the closing, the refrigerant in the liquid side pipe 34 is drawn into the liquid pipe 7 (see the dashed line arrow in FIG. 3).
Here, the other outdoor unit (the outdoor unit whose operation is stopped first) 2 does not have a liquid receiver in the liquid side pipe 34 unlike the one outdoor unit 1 (a feature of the present invention). Therefore, the amount of the refrigerant of the other outdoor unit 2 that is stopped flowing into the one outdoor unit 1 or the like is minimized. This prevents the amount of refrigerant from becoming excessive when one of the outdoor units 1 is operated alone, and adjusts the amount of refrigerant circulated in the receiver 36.

When the amount of refrigerant accumulated in the liquid receiver 36 of one of the outdoor units 1 exceeds a predetermined amount, the valve 50 is opened. By this operation, the high-pressure refrigerant discharged from the compressor 21 flows into the receiver 36, and the excess refrigerant is discharged. In this embodiment, the case where the liquid receiver is not provided in the other outdoor unit 2 has been described. However, in the case where the liquid receiver is provided in the other outdoor unit 2, the liquid receiver 6 is not provided.
0 (see the dashed line in FIG. 3) is made smaller than the capacity of the liquid receiver 36 (see FIG. 2) of the one outdoor unit 1.
Thus, the increase in the amount of refrigerant flowing from the other outdoor unit 2 at the time of stoppage to the one outdoor unit 1 during operation can be suppressed to a small value.

Next, during the heating operation, the four-way valve 29 is set to the broken line state, and the compressors 20 and 50 are operated. Thereby, the refrigerant flows in the direction opposite to the solid line arrow (during the cooling operation).
When the operation of only the other outdoor unit 2 is stopped during the heating operation, the four-way valve 29 in the other outdoor unit 2 enters the cooling operation (solid arrow) state, and the inflow of the refrigerant into the other outdoor unit 2 is minimized. In addition to being suppressed, only the refrigerant in the liquid side pipe 34 is guided to the liquid pipe 7 as in the cooling operation described above.

Further, in these embodiments, the type (rotary or scroll) of the compressor and the variable or constant capacity of the compressor can be changed as required.

[0020]

As described above, according to the present invention, no liquid receiver is provided or the capacity of the liquid receiver is reduced in the outdoor unit whose operation is stopped first in accordance with the decrease in the air conditioning load. It is possible to reduce a possibility that the refrigerant may accumulate in the outdoor unit in which only one outdoor unit is stopped during operation. As a result, the amount of refrigerant as an air conditioner (system) can be reduced. Further, the cost of the air conditioner can be reduced by downsizing or eliminating the liquid receiver.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an air conditioner of the present invention.

FIG. 2 is a refrigerant circuit diagram of one outdoor unit shown in FIG.

FIG. 3 is a refrigerant circuit diagram of the other outdoor unit shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 One outdoor unit 2 The other outdoor unit 3, 4 Indoor unit 5 Unit piping 20 Variable capacity compressor 50 Constant capacity compressor 36, 60 Receiver

Claims (2)

(57) [Claims] A plurality of outdoor units are connected in parallel to an inter-unit pipe extending from an indoor unit, and these outdoor units are connected to one of the outdoor units in accordance with a reduction in air conditioning load. in the air conditioning apparatus prior to the operation was composed of the other of the outdoor unit is stopped, the receiver of which is housed the capacity of the receiver housed in the outdoor unit of the other side to the outdoor unit of the one-way an air conditioning apparatus characterized by being arranged only receiver to small Kushida, or the one outdoor unit than capacity. 2. The air conditioner according to claim 1, wherein the one outdoor unit is adapted to an air conditioning load.
Equipped with a variable capacity compressor that can variably control the capacity
And the other outdoor unit is a fixed capacity compressor.
The air conditioner according to claim 1, further comprising: