JP3326296B2 - 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 a separation type air conditioner comprising an outdoor unit, an indoor unit, and a piping between the units connecting these units.

[0002]

2. Description of the Related Art In a conventional separation type air conditioner, an indoor unit is arranged inside a house and an outdoor unit is arranged outside, and these two units are connected by piping between the units.
Here, in a general household separation type air conditioner, since the length of the interunit piping is about several meters, the amount of refrigerant charged in the interunit piping is very small. Therefore, since the amount of the refrigerant that increases according to the length of the inter-unit pipe is small, the liquid refrigerant can be sufficiently stored in the accumulator, and the compressor is less likely to cause liquid compression when the compressor is started. However, in a separation type air conditioner for business use or for building air conditioning, the installation distance of both units is often longer than that for home use, and may reach 50 m to 100 m.

As an example, in an 8-horsepower separation type air conditioner, the amount of refrigerant in a unit is 6.3 Kg, and when the liquid pipe between units is 50 m or 100 m, the capacity of the pipe is 50 m or 100 m. Is about 5 liters and about 11 liters, and the amount of charged refrigerant is 5 kg and 11 kg, respectively. Further, in a 10-hp separated air conditioner, the refrigerant amount in the unit is 8.3 kg, while the liquid piping between the units is 10 m or 100 m, the capacity of the piping is about 8 kg.
Liter and 16 liters, and the refrigerant charge is 8K each
g, 16 kg. As described above, when the length of the inter-unit piping is increased, the amount of charged refrigerant gradually increases, and the amount of charged refrigerant may be larger than the amount of refrigerant in the unit.

In this type of conventional separation type air conditioner,
The operation of the plurality of indoor units is individually controlled according to the air conditioning load. Conventionally, during cooling operation, for example, 1
When the operation of one indoor unit is stopped, the valve opening of the pressure reducer built in the indoor unit is completely closed so that dew does not occur in the indoor heat exchanger of the stopped indoor unit,
Excess refrigerant that should flow to the indoor heat exchanger is stored in the accumulator. Further, during the heating operation, for example, when the operation of one indoor unit is stopped, the refrigerant does not stagnate in the indoor heat exchanger of the stopped indoor unit, that is, the refrigerant stagnates and the refrigerant circuit is in a gas-free state. In order to avoid this, the degree of opening and closing of the decompressor of the indoor unit is slightly opened, the expansion of the refrigerant is performed by the decompressor built in the outdoor unit, and the surplus refrigerant is stored in the accumulator.

[0005] In consideration of such a case, a large accumulator is built in the outdoor unit.
As shown in Japanese Patent No. 4266, an accumulator kit separate from the unit is arranged.

[0006]

However, if a large accumulator is built in the outdoor unit,
The size of the outdoor unit is inevitable. In addition, the manufacturer will prepare several types of outdoor units with different accumulator sizes according to the length of the piping between units, increasing the number of models, increasing the manufacturing costs of outdoor units and complicating model selection. May cause. on the other hand,
If an accumulator kit separate from the outdoor unit is arranged, a special space for this arrangement is required, and cost increases are inevitable.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional technology and to provide a large accumulator or the like even when one of a plurality of indoor units is stopped. It is another object of the present invention to provide an air conditioner in which refrigerant to be flown into a stopped indoor unit is temporarily stored in a refrigerant circuit, and the refrigerant circuit does not run out of gas.

[0008]

In order to achieve the above object, an invention according to claim 1 comprises an outdoor unit having an outdoor heat exchanger and a plurality of indoor units each having an indoor heat exchanger. In the air conditioner, the operation of each of the indoor units can be individually controlled according to the air conditioning load, the refrigerant discharged from the indoor heat exchanger of the indoor unit stopped during the cooling operation is connected to the outdoor unit. The pipe of the outdoor heat exchanger can be housed inside the heat exchanger, and the pipe of the outdoor heat exchanger is provided so that the refrigerant circuit does not run out of gas even if the refrigerant is accumulated inside the indoor heat exchanger of the indoor unit stopped during the heating operation. A diameter and a pipe diameter of the indoor heat exchanger are set, and the indoor unit is provided with a built-in pressure reducer whose valve opening is fully closed when the operation of the indoor unit is stopped. is there.

[0009]

[0010]

[0011]

According to the present invention , in an air conditioner in which an outdoor unit and a plurality of indoor units are connected by inter-unit piping, first, when any of the indoor units is stopped during the cooling operation, the stopped indoor unit is conventionally stopped. The unit is controlled so that the refrigerant does not flow. In this case, the refrigerant that should flow naturally to the stopped indoor unit becomes excess refrigerant.
According to the present invention, the surplus refrigerant accumulates in the outdoor heat exchanger of the outdoor unit. Since the pipe diameter of the outdoor heat exchanger of this outdoor unit is larger than the pipe diameter of the indoor heat exchanger of the indoor unit, the excess refrigerant can be sufficiently stored without using a large-sized accumulator as in the related art. be able to. During the heating operation, if any of the indoor units is stopped, control is performed to accumulate the refrigerant in the stopped indoor unit as in the related art. According to the present invention, since the pipe diameter of the indoor heat exchanger of the indoor unit is small, a large amount of refrigerant does not accumulate as in the related art, so that the refrigerant circuit does not run out of gas.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the air conditioner according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a separation type air conditioner, which includes an outdoor unit 2 and a plurality of indoor units 3a,
3b, 3c ... and unit-to-unit piping 4 connecting both units
It is composed of The outdoor unit 2 includes a compressor 5
, An oil separator 6, a four-way valve 7, an outdoor heat exchanger 8, a liquid receiver 9, and an accumulator 10. The indoor unit 3 includes indoor heat exchangers 13 a and 13.
b, 13c... and a pressure reducer (also referred to as an “indoor mechanical valve”)
14a, 14b, 14c,... The inter-unit piping 4 is composed of an inter-unit gas pipe 11 and an inter-unit liquid pipe 12.

According to this embodiment, the pipe diameter of the outdoor heat exchanger 8 is made larger than the pipe diameter of the indoor heat exchanger 13. If the pipe diameter of the indoor heat exchanger 13 is φ7 mm, the pipe diameter of the outdoor heat exchanger 8 is increased to about φ9.52 mm.

To describe the cooling operation, the four-way valve 7 is switched to the position indicated by the solid line, and the decompressors 14a, 14b, 1
4c are reduced in accordance with the air conditioning load. As a result, the refrigerant from the compressor 5 flows as shown by the solid arrow. Here, for example, assuming that the second and third indoor units 3b and 3c other than the first indoor unit 3a stop operating, in this embodiment, the opening degrees of the pressure reducers 14b and 14c are fully closed. You. Then, the refrigerant does not flow into the indoor heat exchangers 13b, 13c, and the refrigerant remaining inside the indoor heat exchangers 13b, 13c is sucked into the compressor 5 through the interunit gas pipe 11. The refrigerant sucked into the compressor 5 is discharged from the compressor 5, but the refrigerant that should originally flow into the indoor heat exchangers 13b and 13c becomes surplus refrigerant, and the surplus refrigerant accumulates in the liquid receiver 9, and still remains. The surplus refrigerant accumulates in the outdoor heat exchanger 8 and the inter-unit liquid pipe 12 connected to the stopped second and third indoor units 3b and 3c.

According to this embodiment, the pipe diameter of the outdoor heat exchanger 8 is made larger than the pipe diameter of the indoor heat exchanger 13, and the amount of refrigerant held in the indoor heat exchangers 13b and 13c is determined by the outdoor heat exchanger 13b. Since the amount of refrigerant in the heat exchanger 8 is smaller than that of the indoor heat exchanger 1,
Even if 3b and 13c are stopped, the surplus refrigerant is stored in the outdoor heat exchanger 8 having a large refrigerant holding amount.
Since it is also stored in the inter-unit liquid pipe 12 having a long length connected to the third indoor units 3b and 3c, it is not necessary to install a large accumulator or the like in order to store excess refrigerant as in the conventional case, and the outdoor unit is not required. 2 and cost reduction.

To explain the heating operation, the four-way valve 7 is switched to the position indicated by the dotted line, and the decompressors 14a, 14b, 1
4c are reduced in accordance with the air conditioning load. Thereby, the refrigerant from the compressor 5 flows as shown by the dotted arrow.
Here, for example, if the second and third indoor units 3b and 3c other than the first indoor unit 3a stop operating, in this embodiment, the opening degrees of the pressure reducers 14b and 14c are fully closed, Or it is opened slightly. Then, indoor heat exchanger 1
Refrigerant is stored inside 3b, 13c. Conventionally, when refrigerant is stored in the indoor heat exchangers 13b and 13c, there is a possibility that a gas-out state may occur in the circuit.

Thus, according to this embodiment, the pipe diameter of the indoor heat exchanger 13 is smaller than the pipe diameter of the outdoor heat exchanger 8, and the amount of refrigerant retained in the indoor heat exchanger 13 is: Since the number of the refrigerant circuits is smaller than that of the conventional one, the refrigerant circuit does not run out of gas. The pipe diameter of the conventional indoor heat exchanger 13 is φ
If the diameter is 8.52 mm, in this embodiment, since the diameter is 7 mm as described above, the holding amount of the refrigerant is reduced to about 54% as compared with the holding amount of the conventional indoor heat exchanger. During the heating operation, when an out-of-gas state occurs in the refrigerant circuit, the opening of the decompressors 14b and 14c may be increased from time to time by operating a gas-out sensor (not shown).

In short, according to this embodiment, during the cooling operation, the refrigerant to be flown to the stopped indoor units 3b and 3c is supplied to the outdoor heat exchanger 8 using a large-diameter pipe and the liquid pipe between the units. Since the refrigerant is stored in the storage unit 12, there is no need to use a large accumulator or the like to store the excess refrigerant as in the related art. During the heating operation, even if the refrigerant is stored in the stopped indoor units 3b and 3c, the indoor heat Since the exchangers 13b and 13c have small diameters, the amount of stored refrigerant is relatively small, and there is little possibility that the refrigerant circuit will run out of gas.

As described above, the present invention has been described based on one embodiment, but the present invention is not limited to this embodiment. For example, in the above embodiment, a decompressor (outdoor mechanical valve) is not provided inside the outdoor unit 2, but the outdoor mechanical valve may be provided between the outdoor heat exchanger 8 and the liquid receiver 9. It is clear.

[0021]

As is clear from the above description, according to the present invention , since the pipe diameter of the outdoor heat exchanger and the pipe diameter of the indoor heat exchanger are appropriately set, for example, cooling Refrigerant discharged from the indoor heat exchanger of the indoor unit stopped during operation is housed inside the outdoor heat exchanger, and the excess refrigerant can be sufficiently stored without using a large-sized accumulator as in the related art. However, even if the refrigerant accumulates inside the indoor heat exchanger of the indoor unit stopped during the heating operation, for example, the amount of the accumulated refrigerant is suppressed, so that the refrigerant circuit does not run out of gas.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Separation type air conditioner 2 Outdoor unit 3a, 3b, 3c Indoor unit 4 Unit piping 5 Compressor 6 Oil separator 7 Four-way valve 8 Outdoor heat exchanger 9 Liquid receiver 10 Accumulator 13a, 13b, 13c Indoor heat exchanger 14a , 14b, 14c Pressure reducer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 13/00 F25B 1/00 F25B 41/00

Claims (1)

(57) [Claims] An indoor unit having an outdoor heat exchanger and a plurality of indoor units each having an indoor heat exchanger are connected by unit piping, and each of the indoor units is individually operated according to an air conditioning load. In the air conditioner that can be controlled, the refrigerant discharged from the indoor heat exchanger of the indoor unit stopped during the cooling operation can be stored inside the outdoor heat exchanger, and the indoor heat of the indoor unit stopped during the heating operation. The pipe diameter of the outdoor heat exchanger and the pipe diameter of the indoor heat exchanger are set so that the refrigerant circuit does not run out of gas even if the refrigerant accumulates inside the exchanger. An air conditioner characterized by incorporating a pressure reducer whose valve opening is completely closed when the operation of the indoor unit is stopped.