JPH07305915A - Air conditioner - Google Patents

Abstract

PURPOSE:To effectually utilize an outdoor heat exchanger by providing means for operating a variable compressor included in one outdoor unit with upper limit horsepower lower than maximum horsepower and starting operation of a compressor included in time other outdoor unit when air conditioning load is increased. CONSTITUTION:Variable compressors, i.e., inverters A, B contained in each outdoor unit 11, 12, 13 have set upper and lower limit horsepowers. The upper limit horsepower is set to 80% of a maximum capability of the inverter compressor, i.e., to a lower value than a maximum operation horsepower. In contrast, the lower limit horsepower is set to 30%, i.e., to a higher value than a minimum operation horsepower. For example, when an air conditioning load is 0 to 5.4 horsepower, only the inverter compressor A is operated. When the air conditioning load exceeds 8 horsepower, the inverter compressors A and B are operated. When the air conditioning load exceeds 14.4 horsepower, the inverter compressors A, B, and C are operated.

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 inter-unit piping extending from an indoor unit.

[0002]

2. Description of the Related Art Generally, a plurality of indoor units are arranged in parallel, and a plurality of outdoor units containing a compressor, an outdoor heat exchanger, etc. are arranged in parallel with respect to inter-unit piping connected to each indoor unit. A multi-type air conditioner for connected buildings is known (for example, Japanese Patent Application Laid-Open No. HEI 2-
85656).

This type of multi-type air conditioner is provided with a plurality of outdoor units.
There is an advantage that a large capacity system of the device can be achieved.

[0004]

However, in the conventional multi-type air conditioner, when the air conditioning load is small,
Since the operation of the extra outdoor unit is stopped, there is a problem that the outdoor heat exchanger of the stopped outdoor unit cannot be effectively used.

In the above case, if the outdoor heat exchanger can be effectively used, the electric efficiency can be improved and energy saving can be achieved.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technique and to operate as many outdoor units as possible to effectively use the outdoor heat exchanger even when the air conditioning load is small. An object is to provide an air conditioner capable of achieving the above.

[0007]

In order to achieve the above object, a first aspect of the present invention is to connect a plurality of outdoor units in parallel to an inter-unit pipe extending from an indoor unit, and to connect the plurality of outdoor units according to the air conditioning load. In an air conditioner that controls the number of operating outdoor units, while operating the variable capacity compressor built in one outdoor unit with an upper limit horsepower lower than the maximum horsepower, when the air conditioning load further increases during that operation, The other outdoor unit is provided with an upper limit horsepower control means for starting the operation of the compressor.

A second aspect of the present invention is an air conditioner for controlling the operating number of these plural outdoor units in accordance with the air conditioning load, and in the variable capacity compressor incorporated in one of the outdoor units, the compressor is the compressor. The lower limit horsepower higher than the minimum operating horsepower of the compressor and the upper limit horsepower lower than the maximum operating horsepower of the compressor are provided to start the operation and when the air conditioning load changes more than a predetermined amount (the operation button of the indoor unit is turned on or off). The required indoor capacity (for example, when the indoor temperature is set to the indoor temperature and the indoor unit is thermo-OFF or vice versa) is the lower limit horsepower of the variable capacity compressor built in one outdoor unit. And the capacity of the compressor built in the other outdoor unit, the lower limit horsepower control means for starting the operation of both the outdoor units and the variable capacity type of the one outdoor unit. With operating the compressor at an upper limit horsepower, in which case, and a limit power control means for starting the operation of the compressor incorporated in the other of the outdoor unit to which the further air-conditioning load increases during operation.

[0009]

According to the present invention, in a so-called multi-type air conditioner, when the air conditioning load changes, the operation of the compressor is controlled according to the air conditioning load. In this case, first, if the lower limit horsepower is set, the lower limit horsepower of the compressor of the outdoor unit with the first air conditioning load and the second outdoor If the sum exceeds the lower limit horsepower of the compressor of the unit, the two outdoor units are operated, and if it is less than that, the first outdoor unit is operated. Further, when the air conditioning load increases and exceeds the lower limit horsepower of the compressors of the first, second and third outdoor units, the compressor of the third outdoor unit is operated. When controlled in this way, if a predetermined upper limit horsepower lower than the maximum horsepower is set, the compressors of other outdoor units will start operating when the air conditioning load reaches the upper limit horsepower. In the above example, the compressor of the third outdoor unit is operated earlier than in the case where the upper limit horsepower is not set. Therefore, the compressor of the outdoor unit does not continue to operate up to the maximum horsepower, and the compressors of the many outdoor units are operated almost evenly,
A large number of outdoor heat exchangers are effectively used.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numerals 1 ₁ , 1 ₂ and 1 ₃ denote outdoor units, and 3 ₁ and 3 ₂ denote indoor units. The outdoor units 1 ₁ and 1 ₂ are accumulators 10.
₁ and 10 ₂ , variable capacity compressors A and B capable of variably controlling the capacity according to the air conditioning load, and oil separators 12 ₁ and 12 _2.
, Four-way valves 13 ₁ and 13 ₂ and outdoor heat exchangers 14 ₁ and 1
4 ₂ and outdoor electric expansion valves 15 ₁ and 15 ₂ .

The outdoor unit 1 ₃ includes an accumulator 10 ₃ , a constant capacity compressor C, and an oil separator 12
₃ , a four-way valve 13 ₃ , an outdoor heat exchanger 14 _3, and an outdoor electric expansion valve 15 ₃ .

The indoor units 3 ₁ and 3 ₂ include an indoor heat exchanger 34 ₁ and 34 ₂ and an indoor electric expansion valve (indoor mechanical valve) 3
5 ₁ and 35 ₂ . This indoor unit 3 ₁ ,
An inter-unit pipe consisting of the gas pipe 5 and the liquid pipe 7 extends from 3 ₂ , and the outdoor units 1 ₁ , 1 ₂ , 1 ₃ are connected in parallel to the inter-unit pipe.

The oil separators 12 ₁ , 12 ₂ and 12 ₃ of the outdoor units 1 ₁ , 1 ₂ and 1 ₃ separate the lubricating oil in the refrigerant discharged from the compressors A, B and C, respectively. Yes, the lubricating oil separated here is the return pipes 21 ₁ , 21 ₂ , 21 _3.
Through the compressors A, B, and C, respectively. Further, the return pipes 21 ₁ , 21 ₂ , and 21 ₃ are provided with open / close valves 23 ₁ , 2 respectively.
3 ₂ and 23 ₃ are provided.

Return pipes 2 of the outdoor units 1 ₁ , 1 ₂ and 1 ₃
The balance pipes 51 connect 1 ₁ , 21 ₂ , and 21 ₃ .

The balance pipe 51 changes from a compressor with a large amount of lubricating oil to a compressor with a small amount of lubricating oil when an unbalance in the amount of lubricating oil occurs between the compressors of the outdoor units 1 ₁ , 1 ₂ , 1 _3. It is a conduit for guiding the.

Referring to FIG. 2, the compressor A is a variable capacity compressor of 10 horsepower whose capacity can be variably controlled according to the air conditioning load, and the compressor B is also a variable capacity compressor of 6 horsepower. , The compressor C is an eight horsepower constant capacity compressor.

By the way, in the multi-type air conditioner of such a combination, for example, when the air conditioning load decreases below the maximum output of the outdoor unit during operation, control is performed to stop the operation of some outdoor units.

In performing such control, the upper limit horsepower and the lower limit horsepower are set in the variable capacity compressors (hereinafter referred to as "inverter") compressors A and B housed in the outdoor units 1 ₁ , 1 ₂ and 1 ₃ , respectively. ing. Here, the upper limit horsepower is set to 80% of the maximum capacity of the inverter compressor, that is, a value lower than the maximum operating horsepower. On the other hand, the upper limit horsepower is set to 30% of the maximum capacity of the inverter compressor, that is, a value higher than the minimum operating horsepower.

In this apparatus, for example, when the air conditioning load at the start of operation is in the range of 0 to 5.4 horsepower, it corresponds to the α zone and only the inverter compressor A is operated. After the start of this operation, the air conditioning load corresponds to the β zone at some horsepower (5.4 horsepower to 8 horsepower) in the range of 0 to 8 horsepower, but only the inverter compressor A is kept operating. That is, even if the air conditioning load is in the range of 5.4 horsepower to 8 horsepower, since the operation before that is only the inverter compressor A, the operation is not changed to the two operation, and the operation is not changed. Continue operation of one unit to prevent frequent start and stop of the compressor. However, if the air-conditioning load exceeds 8 horsepower, the inverter compressors A and B will be operated because they correspond to the β zone. The two units are kept in operation until the air conditioning load reaches 14.4 horsepower. Here, although the air conditioning load corresponds to the γ zone (three-vehicle operating zone) in the range of 13.4 to 14.4 horsepower, the two-vehicle operation is continued for the reason described above. When the air conditioning load exceeds 14.4 horsepower, three units will operate.

On the other hand, the air conditioning load at the start of operation is 5.4 to
In the case of the range of 8 horsepower, although it corresponds to the α zone, the β zone with a large number of operating units is prioritized and the two inverter compressors A and B are operated. When the air conditioning load fluctuates in the range of 5.4 to 14.4 horsepower after the start of this operation, it corresponds to the γ zone at a part of the horsepower (13.4 to 14.4 horsepower). Keep two cars operating with B. This is similar to the above case when the air conditioning load is 13.
Even if it is in the range of 4 horsepower to 14.4 horsepower, since the operation before that was two inverter compressors A and B, it is not necessary to shift to the operation of three compressors.
Continue to operate the machine. However, the air conditioning load is 1
If 4.4 horsepower is exceeded, it corresponds to the γ zone, so that three inverter compressors A and B and a rated compressor C are operated.

FIG. 4 shows a summary of these matters. If the air conditioning load is in the range of 0 to 5.4 horsepower at the start of operation, only one inverter compressor A is operated, 5.4.
Operation of the compressor (unit) at the start of operation, such as two operation of the inverter compressors A and B in the range of horsepower to 13.5 horsepower, and three operation of 13.4 horsepower or more. The lower limit horsepower control means decides (5.4 horsepower and 13.4 horsepower) so that the number of vehicles is as large as possible.

On the other hand, once the operation is started, if there is a zone in which the number of operating compressors is large in addition to the zone in which the operation is started, the zone is moved to that zone, and as many zones as possible are moved. The compressor (unit) is operated, and this is the upper limit horsepower control means. By these control means, each unit (compressor or outdoor heat exchanger) is operated with a margin and electric efficiency is improved.

It goes without saying that these means are performed by a controller (not shown) connected to each unit.

Regarding the combination of compressors, the one shown in FIG. 2 is only an example, and it goes without saying that various combinations are possible.

FIG. 5 shows another embodiment.

Reference numerals 71 ₁ , 71 ₂ and 71 ₃ indicate outdoor units, and reference numerals 73 ₁ , 73 ₂ and 73 ₃ indicate indoor units. The outdoor units 71 ₁ and 71 ₂ include accumulators 91 ₁ and 91 ₂ and variable capacity compressors A and B, respectively.
If, the oil separator 92 _1, 92 _2, the outdoor heat exchanger 93 _1,
93 ₂ and outdoor electric expansion valves 94 ₁ and 94 ₂ . The outdoor unit 71 ₃ is constituted by a accumulator 91 _3, and ability constant compressor C, an oil separator 92 _3, an outdoor heat exchanger 93 _3, and the outdoor electric expansion valve 94 _3. The indoor units 73 ₁ and 73 ₂ include indoor heat exchangers 97 ₁ and 97 ₂ and an indoor electric expansion valve (indoor mechanical valve) 9
8 ₁ and 98 ₂ .

The indoor units 73 ₁ , 73 ₂ , 73 ₃ and
A high pressure gas pipe 81 is provided between the outdoor units 71 ₁ and 71 _2.
And the low-pressure gas pipe 83 and the liquid pipe 85 are connected by an inter-unit pipe 8. The heat exchangers 75 ₁ , 75 ₂ of the indoor units 73 ₁ , 73 ₂ , 73 ₃ are connected to the pipes 81, 83, 85, respectively. , 75 ₃ to act as a condenser or an evaporator, switching valves a, b, for switching the refrigerant flow paths
c, d, e, f, g, h, i, j are provided.

That is, according to this configuration, the switching valves a, b,
By appropriately switching among c, d, e, f, g, h, i, and j, the flow of the refrigerant changes, and for example, one indoor unit 73 ₁ , 73 ₂ is heated while operating the other indoor unit 73. ₃ can be cooled. Note that 101
Is a balance pipe that connects the return pipes 103 ₁ , 103 ₂ , and 103 ₃ .

Even in this type of multi-type air conditioner,
By providing the variable capacity compressors A and B with the lower limit horsepower and the upper limit horsepower during operation, it is possible to effectively use the outdoor heat exchangers.

[0031]

As is apparent from the above description, according to the present invention, in the multi-type air conditioner having a plurality of outdoor units, the lower limit horsepower and the upper limit horsepower are set, so that each outdoor unit is almost Because it is driven evenly,
The outdoor heat exchanger built in each outdoor unit can be effectively used.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing an example of an air conditioner according to the present invention.

FIG. 2 is a diagram showing an upper limit horsepower and a lower limit horsepower of each compressor.

FIG. 3 is a diagram showing an example of operation control when a lower limit horsepower and an upper limit horsepower are set.

FIG. 4 is an explanatory diagram summarizing FIGS. 2 and 3.

FIG. 5 is a refrigerant circuit diagram showing another embodiment.

[Explanation of symbols]

1 ₁ , 1 ₂ , 1 ₃ Outdoor unit 3 Indoor unit 5 Gas pipe 7 Liquid pipe 10 ₁ , 10 ₂ , 10 ₃ Accumulator 14 ₁ , 14 ₂ , 14 ₃ Outdoor heat exchanger A, B Variable capacity compressor C Capacity Constant compressor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F25B 13/00 U 104

Claims (2)

[Claims] 1. An air conditioner for connecting a plurality of outdoor units in parallel to an inter-unit pipe extending from an indoor unit and controlling the operating number of the plurality of outdoor units according to an air conditioning load, wherein one outdoor unit is provided. The upper limit horsepower control that operates the built-in variable capacity compressor with an upper limit horsepower lower than the maximum horsepower, and starts the operation of the compressor built in the other outdoor unit when the air conditioning load further increases during the operation. An air conditioner provided with means. 2. An air conditioner in which a plurality of outdoor units are connected in parallel to inter-unit piping extending from an indoor unit and the number of operating units of the plurality of outdoor units is controlled according to an air conditioning load, and one outdoor unit is provided. The built-in variable capacity compressor is provided with a lower limit horsepower higher than the minimum operating horsepower of the compressor and an upper limit horsepower lower than the maximum operating horsepower of the compressor, at the start of operation of this air conditioner and / Or the required operating capacity from the room during operation of this device is the sum of the lower limit horsepower of the variable capacity compressor built in one outdoor unit and the capacity of the compressor built in the other outdoor unit. If it is larger, the lower limit horsepower control means for starting the operation of both outdoor units and the variable capacity compressor of one of the outdoor units are operated at the upper limit horsepower, and further air conditioning is performed during the operation. An air conditioner comprising: an upper limit horsepower control means for starting the operation of a compressor incorporated in the other outdoor unit when the load increases.