JPH10281566A - Outdoor device of heat pump type air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a difference in oil volume returning to a plurality of compressors from being generated by a method wherein the other end of a hot gas bypassing circuit for controlling a volume having one end connected to a merging flow discharging pipe is connected to a common suction pipe before it is branched to branched suction pipes of a plurality of compressors. SOLUTION: As a bypassing valve 28 is opened, hot gases discharged out of the compressors 1 and 2 enter a merging discharging pipe 33 through discharging pipes 35, 36. After the gases are merged there, a part of the gases passes through a hot gas bypassing circuit 27, a bypassing valve 28 installed in the hot gas bypassing circuit and also through a fixed throat 29 and enters a common suction pipe 34. Then, the gases are merged with gaseous refrigerant returned from a four-way changing-over valve 3, the gas is branched through an accumulator 18 and a common suction pipe 34, and then the gas is sucked into the compressors 1 and 2 through the branched suction pipes 31, 32. Accordingly, even in the case that the bypassing valve 28 is opened, no difference is produced in suction pressures of the compressors 1 and 2, resulting in that amounts of oil returning to the compressors 1 and 2 may become equal to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outdoor unit of a heat pump type air conditioner having a plurality of fixed displacement compressors.

[0002]

2. Description of the Related Art One example of a conventional heat pump type air conditioner is shown in FIG. A plurality (two in the figure) of fixed-capacity type units each having a plurality of (two in the figure) outdoor units A and B connected in parallel to the refrigerant circuit are respectively provided for a plurality of (only two are shown in the figure) The compressors 1, 2, a four-way switching valve 3, an outdoor heat exchanger 4, an accumulator 18, and the like are mounted. An indoor heat exchanger 5 and the like are mounted on a plurality of indoor units P and Q (only two are shown in the figure).

The plurality of outdoor units A,
B and the plurality of indoor units P and Q are connected in parallel to the connection gas pipe 7 and the connection liquid pipe 8, respectively.

[0004] During the cooling operation of the air conditioner,
The high-temperature and high-pressure gas refrigerant discharged from the compressors 1 and 2 of each of the outdoor units A and B passes through the check valves 9 and 10 and the four-way switching valve 3 to the outdoor heat exchanger 4 as shown by solid arrows. It enters and condenses and liquefies by exchanging heat with the outside air.

The liquid refrigerant enters the connection liquid pipe 8 through the check valve 11, the receiver 12, and the liquid-side operation valve 13 and merges there, and then flows into each of the indoor units P and Q through the liquid-side operation valve 14. . After adiabatic expansion in the process of flowing through the cooling expansion valve 15, the air enters the indoor heat exchanger 5, where the indoor air is cooled to evaporate.

The gas refrigerant enters the connecting gas pipe 7 via the gas-side operation valve 16 and merges there, then flows into each of the outdoor units A and B via the gas-side operation valve 17, and the four-way switching valve 3, the accumulator 18 After that, it is branched and drawn into the compressors 1 and 2.

During the heating operation of the air conditioner, the four-way switching valve 3 is switched in the opposite direction, so that the refrigerant discharged from the compressors 1 and 2 receives the check valve 9,
10, the four-way switching valve 3, the gas-side operation valve 17, the connecting gas pipe 7, and the gas-side operation valve 16, enter the indoor heat exchanger 5 of each indoor unit P, Q, and condense by releasing heat to indoor air here. Liquefy.

The liquid refrigerant enters the outdoor units A and B via the check valve 6, the liquid-side operation valve 14, the connecting liquid pipe 8, and the liquid-side operation valve 13, and passes through the receiver 12 to the heating expansion valve 19. After adiabatic expansion in the flow process, it enters the outdoor heat exchanger 4 where it absorbs heat from outside air and evaporates. Next, the gas refrigerant is sucked into the compressors 1 and 2 via the four-way switching valve 3 and the accumulator 18.

When the air conditioning load decreases due to a decrease in the number of operating indoor units P and Q, the bypass valve 28 interposed in the capacity control hot gas bypass circuit 27 of the outdoor unit A is opened to compress the air. A part of the hot gas discharged from the compressor 1 flows into the branch suction pipe 31 of the compressor 1 through the hot gas bypass circuit 27 for capacity control, the bypass valve 28, and the fixed throttle 29, whereby the capacity of the compressor 1 is reduced. descend.

When the air-conditioning load further decreases, the compressor 1 stops, and then the compressor 2 stops. Further, when the air conditioning load decreases, the bypass valve 28 of the outdoor unit B opens, and the compressors 1 and 2 stop in this order. When the air-conditioning load increases, the operation is performed in the reverse order, and the capacity of the compressor gradually increases.

[0011]

In the above-mentioned conventional air conditioner, when the bypass valve 28 is opened, the hot gas flows into only the branch suction pipe 31 of the compressor 1 through the bypass circuit 27. 1, a difference occurs between the pressure of the gas refrigerant sucked into the compressor 1 and that of the compressor 2, and as a result, a difference occurs between the amount of oil returning to the compressor 1 and that of the compressor 2. .

[0012]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and the gist of the present invention is that a plurality of units of the same capacity connected in parallel to a refrigerant circuit are provided. In an outdoor unit of a heat pump type air conditioner equipped with a fixed displacement compressor, a four-way switching valve, an outdoor heat exchanger, an accumulator, etc., a merging discharge pipe into which hot gases discharged from the plurality of compressors merge. An outdoor unit of a heat pump type air conditioner, wherein the other end of the capacity control hot gas bypass circuit having one end connected to a common suction pipe before branching to the branch suction pipes of the plurality of compressors. It is in.

Another feature is that the other end of the capacity control hot gas bypass circuit is connected to a common suction pipe downstream of the accumulator.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. One end of a capacity control hot gas bypass circuit 27 is connected to a merging / discharging pipe 33 where hot gases discharged from the compressors 1 and 2 merge, and the other end branches to branch suction pipes 31 and 32 of the compressors 1 and 2. Before being connected between the four-way switching valve 3 of the common suction pipe 34 and the accumulator 18. The other configuration is the same as that of the conventional one shown in FIG. 3, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

When the bypass valve 28 is opened, the hot gas discharged from the compressors 1 and 2 enters the merged discharge pipe 33 via the discharge pipes 35 and 36 and merges there. The gas enters the common suction pipe 34 via the bypass circuit 27 and the bypass valve 28 and the fixed throttle 29 interposed therebetween.

Then, the refrigerant merges with the gas refrigerant returned from the four-way switching valve 3 and branches through the accumulator 18 and the common suction pipe 34, and is sucked into the compressors 1 and 2 through the branch suction pipes 31 and 32. Thus, even when the bypass valve 28 is opened, there is no difference between the suction pressures of the compressors 1 and 2, so that the amount of oil returning to the compressors 1 and 2 is equal.

A second embodiment of the present invention is shown in FIG. In the second embodiment, the other end of the capacity control hot gas bypass circuit 27 is connected to a common suction pipe downstream of the accumulator 18, that is, to the accumulator 18 and the branch suction pipes 31, 32 of the compressors 1, 2. Are connected to a common suction pipe 34 connecting the branch points of the two. Other configurations are the same as those of the first embodiment shown in FIG. 1, and corresponding members are denoted by the same reference numerals and description thereof will be omitted.

When the bypass valve 28 is opened, hot gas that has passed through the hot gas bypass circuit 27 enters the common suction pipe 34 downstream of the accumulator 18 and is compressed through the branch suction pipes 31 and 32. Because it is inhaled by Aircraft 1 and 2,
The amount of oil returning to the compressors 1 and 2 will be equal.

Further, since the flow rate of the gas refrigerant flowing into the accumulator 18 does not increase, the accumulator
Noise generated from 18 can be suppressed.

[0020]

According to the present invention, at the time of capacity control, hot gases discharged from a plurality of compressors are joined by a merge discharge pipe, and a part of the hot gas flows through a capacity control hot gas bypass circuit. Since the oil enters the common suction pipe before branching and is sucked into a plurality of compressors via the branch suction pipe, it is possible to prevent a difference in the amount of oil returning to the plurality of compressors.

If the other end of the capacity control hot gas bypass circuit is connected to a common suction pipe on the downstream side of the accumulator, not only the above effect can be obtained, but also the flow rate of the gas refrigerant flowing into the accumulator increases. Can be prevented, so that the cost can be reduced by eliminating the shielding device for shielding the noise generated from the accumulator.

[Brief description of the drawings]

FIG. 1 is a system diagram of an outdoor unit according to a first embodiment of the present invention.

FIG. 2 is a system diagram of an outdoor unit according to a second embodiment of the present invention.

FIG. 3 is a system diagram of a conventional heat pump type air conditioner.

[Explanation of symbols]

 A Outdoor unit 1, 2 Compressor 3 Four-way switching valve 4 Outdoor heat exchanger 18 Accumulator 27 Hot gas bypass circuit 28 Bypass valve 29 Fixed throttle 35, 36 Discharge pipe 33 Combined discharge pipe 31, 32 Branch suction pipe 34, Common suction pipe

Claims (2)

[Claims] 1. An outdoor air conditioner of a heat pump type air conditioner comprising a plurality of fixed capacity compressors of the same capacity, a four-way switching valve, an outdoor heat exchanger, an accumulator, etc., connected in parallel to a refrigerant circuit. In the unit, the other end of the capacity control hot gas bypass circuit, one end of which is connected to a merging / discharging pipe into which the hot gases discharged from the plurality of compressors merge, is branched to a branch suction pipe of the plurality of compressors. An outdoor unit of a heat pump type air conditioner, wherein the outdoor unit is connected to a common suction pipe in front of the air conditioner. 2. The outdoor unit according to claim 1, wherein the other end of the capacity control hot gas bypass circuit is connected to a common suction pipe downstream of the accumulator.