JPH11132603A - Air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive effective operation when any one of outdoor units carries out defrosting operation in a heat-pump type air-conditioner comprising an indoor unit and an outdoor unit. SOLUTION: In this air-conditioner, switching valves 22A, 22B (22) are provided on outlet sides of compressors 1A, 1B (1) in each of outdoor units, and hot gas-bypassing circuits 23A, 23B (23) connecting to inlet sides of outdoor heat exchangers 2A, 2B (2) from the switching valves 22 are provided. Piping 18 connecting to each other of inlet sides of the compressors 1 of each of the outdoor units is provided, and refrigerant-controlling valves 27A, 27B (27) are provided on both end parts of the piping 18. When the outdoor unit A has to be operated for defrosting, the switching valve 22A is allowed to operate in the outdoor unit A, and high-temperature refrigerant gas from the compressor 1A is introduced into the outdoor heat exchanger 2A via the hot gas-bypassing circuit 23A, and a part of the refrigerant returning from the indoor units A, B is introduced to the outdoor heat exchanger 2A as refrigerant gas via an outdoor expansion valve 21A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner which comprises a refrigeration cycle by connecting one or more indoor units and a plurality of outdoor units by the same piping system. It relates to a frost driving method.

[0002]

2. Description of the Related Art When a heat pump type air conditioner is heated, frost may be formed on the surface of an outdoor heat exchanger.
As the frost blocks the heat exchanger, the heat exchange capacity of the air conditioner is reduced, which affects comfort. For this reason, frost formation is periodically determined and defrosting operation for removing frost is performed.

There are mainly two types of defrosting operation methods. That is, one is a reverse cycle defrosting method in which a four-way valve is reversed, a refrigeration cycle operation in the same direction as the cooling operation is performed, and hot gas is sent to the outdoor heat exchanger to defrost the surface. The other is a hot gas bypass defrosting method in which hot gas is bypassed from the compressor outlet to the outdoor heat exchanger inlet to melt frost. In the reverse cycle defrosting method, defrosting can be performed in a short time because the indoor heat exchanger is used as a low heat source (evaporator). However, there is a drawback that cool air flows out into the room and gives a sense of cool air. Further, in the hot gas bypass defrosting method, since both the outdoor and indoor heat exchangers use a high heat source (condenser), it does not give a feeling of cool air to the room, but has a disadvantage that the defrosting time is long.

Here, as an example in which an air conditioner having a plurality of outdoor units connected thereto performs a hot gas bypass defrosting operation, there is, for example, Japanese Patent Application Laid-Open No. Hei 4-324075. In this known example, of the plurality of outdoor units, the refrigerant discharged from this outdoor unit is guided to the outdoor heat exchanger of the outdoor unit for defrosting for the outdoor unit that has become the condition for starting defrosting. We are going to drive.

[0005]

In the above prior art, since the defrosting operation method is a hot gas bypass defrosting method, when the heat capacity of the refrigerant and the compressor is smaller than the heat capacity required for defrosting, There is a possibility that defrosting may not be performed properly (defrosting time may be prolonged or frost may remain undissolved).

Accordingly, an object of the present invention is to provide an air conditioner having a plurality of outdoor units, in which an air unit for performing a good defrost operation when performing a hot gas bypass defrost operation on an outdoor unit to be subjected to a defrost operation. It is to provide a harmony device.

[0007]

In order to achieve the above object, a first invention of the present invention is to provide at least one indoor unit having an indoor heat exchanger and an indoor expansion valve, a compressor,
A four-way valve, an outdoor heat exchanger, and a plurality of outdoor units including an outdoor expansion valve, wherein the refrigerant discharged from the compressor during heating is a four-way valve, an indoor heat exchanger, an indoor expansion valve, an outdoor expansion valve, and A heat pump type air conditioner for forming a refrigeration cycle which returns to a compressor via a four-way valve through an outdoor heat exchanger in order, wherein each outdoor unit is provided with a switching valve on the compressor outlet side. A hot gas bypass circuit connected to the outdoor heat exchanger inlet side is provided from when, when one of the plurality of outdoor units is in a state to perform defrosting operation,
In the outdoor unit to be defrosted, the switching valve is operated to guide the high-temperature refrigerant gas from the compressor to the outdoor heat exchanger through the hot gas bypass circuit and to return a part of the refrigerant returning from the indoor unit through the outdoor expansion valve. It is controlled so that it is guided to an outdoor heat exchanger.

According to a second aspect of the present invention, in addition to the air conditioner of the first aspect, a connecting pipe for connecting the compressor entrance sides of adjacent outdoor units and refrigerant at both ends of the pipe are provided. A control valve is provided, wherein both refrigerant control valves are opened to control a part of the refrigerant gas returning to the compressor in the indoor unit of the defrosting operation to move to the outdoor unit of the heating operation through the connection pipe. I do.

Further, according to a third aspect of the present invention, similarly to the air conditioner of the first aspect, the refrigerant discharged from the compressor during heating is a four-way valve, an indoor heat exchanger, an indoor expansion valve, and an outdoor expansion. A heat pump type air conditioner which forms a refrigeration cycle which returns to a compressor via a four-way valve through a valve and an outdoor heat exchanger in order, wherein each outdoor unit branches off from a compressor outlet side to perform outdoor heat exchange. Connected to the vessel entrance side, and provided with a hot gas bypass circuit equipped with a bypass control valve, when any of the plurality of outdoor units are in a state to be defrosting operation,
In the outdoor unit to be defrosted, the bypass control valve is operated to guide the high-temperature refrigerant gas from the compressor to the outdoor heat exchanger through the hot gas bypass circuit and to return the refrigerant returning from the indoor unit to the outdoor through the outdoor expansion valve. It is characterized in that it is controlled so as to lead to a heat exchanger.

In a fourth aspect of the present invention, in addition to the air conditioner of the third aspect, there is provided a connecting pipe for connecting the compressor-incoming sides of the adjacent outdoor units and a refrigerant at both ends of the pipe. A control valve is provided, wherein both refrigerant control valves are opened to control a part of the refrigerant gas returning to the compressor in the indoor unit of the defrosting operation to move to the outdoor unit of the heating operation through the connection pipe. I do.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an air conditioner according to a first embodiment of the present invention, which is a large-capacity multi-type air conditioner in which a group of a plurality of outdoor units and a group of a plurality of indoor units are connected to each other. It is. FIG. 1 shows a case where there are two outdoor units and two indoor units, but a combination of more units may be used.

In FIG. 1, the refrigerating cycle is such that each indoor unit A, B comprises an indoor heat exchanger 8, an indoor heat exchange blower 9, an indoor expansion valve 10, etc., and each outdoor unit A, B Compressor 1, outdoor heat exchanger 2, oil separator 3, four-way valve 4, accumulator 5, refrigerant amount regulator 6,
It comprises a gas bypass control valve 11, an outdoor expansion valve 21, a switching valve 22, and the like. In the drawings, subscripts A and B are added after the reference numerals of the respective components. Further, the outdoor unit group and the indoor unit group are connected by a common gas pipe 19 and a common liquid pipe 20. An oil control valve that can be opened and closed in both directions
15A, 15B (solenoid valve) is the oil separator of each outdoor unit A, B
It is provided in the oil equalizing pipe 18 that connects between 3A and 3B,
Refrigerant control valves 27A and 27B that can be opened and closed in both directions (solenoid valves)
However, as shown in FIG. 1, they are connected to pipes inside the outdoor units A and B, respectively. The outdoor unit A and the outdoor unit B are connected via the control valves 15, 27 and the oil equalizing pipe 18.

Although the air conditioner of the present embodiment is a heat pump type air conditioner capable of performing both cooling and heating operations, the present invention relates to refrigeration cycle control during heating operation. Will be described.

At the time of heating operation, in each outdoor unit,
First, the high-temperature and high-pressure refrigerant gas compressed and discharged by the compressor 1 is sent out from each outdoor unit via the oil separator 3, the switching valve 22, the check valve 14, and the four-way valve 4, where they are merged and shared. After passing through the pipe 19, it branches at the outlet of the pipe 19, enters each of the indoor units A and B, and is heat-exchanged (condensed) by the indoor heat exchanger 8 to become a liquid refrigerant. The liquid refrigerant exits from each indoor unit via the indoor expansion valve 10 and merges there, passes through the common liquid pipe 20, and
After branching at the outlet 20, the refrigerant enters each of the outdoor units A and B, passes through the refrigerant amount regulator 6, is decompressed by the outdoor expansion valve 21, is heat-exchanged (evaporated) by the outdoor heat exchanger 2, and becomes a low-pressure gas refrigerant. The flow returns to the compressor 1 via the murator 5.

Here, in the outdoor unit A, when the surface of the outdoor heat exchanger 2A is frosted and the defrosting operation is required, the outdoor blower 7A is stopped and at the same time, the outdoor switching valve 22 is turned off.
A is activated, and the high-temperature refrigerant gas that has been sent to the indoor unit side through the check valve 14A and the four-way valve 4A until then is checked.
It is sent to the outdoor heat exchanger 2A through the hot gas bypass circuit 23A that branches off at the 14A entry side. On the other hand, the outdoor unit B
Continues the heating operation, and the liquid refrigerant that has been heat-exchanged (condensed) in each of the indoor units A and B returns to the outdoor unit through the common liquid pipe 20 and branches off at the pipe 20 outlet. The other unit enters the outdoor unit B and the other enters the outdoor heat exchanger 2A via the outdoor expansion valve 21A of the outdoor unit A. Outdoor heat exchanger 2A
The refrigerant sent from the compressor 1 via the hot gas bypass circuit 23A and the refrigerant from the indoor unit through the common liquid pipe 20 and the outdoor expansion valve 21A flow there, and heat exchange (condensation) there, Thaw surface frost. Further, in the outdoor unit A during the defrosting operation, when it is determined that the refrigerant circulation amount is large, the refrigerant control valves 27A and 27B are opened, and the refrigerant flowing in the outdoor unit A through the oil equalizing pipe 18 is opened. A part is flowed to the outdoor unit B. Here, when the refrigerant in the outdoor unit B is large, a part of the refrigerant flows from the outdoor unit B to the outdoor unit A through the oil equalizing pipe 18. In addition, the path composed of the refrigerant control valve 27A, the oil equalizing pipe 18, and the refrigerant control valve 27B
The two outdoor units A and B are connected to each other on the entry side of the compressor 1.

On the other hand, in the outdoor unit B, when the surface of the outdoor heat exchanger 2B is frosted and the defrosting operation is required, the positions of the outdoor units A and B are reversed, and During the defrosting operation in the same procedure as in the case where the unit B is the outdoor unit A described above, the outdoor unit A continues the heating operation.

As described above, the refrigerant from the hot gas bypass circuit and the refrigerant from the common liquid pipe are put into the outdoor heat exchanger of the outdoor unit to be defrosted, and the defrosting operation is performed. Good circulation of refrigerant to the outdoor heat exchanger is ensured, and good defrosting operation can be performed.

In the first embodiment, in the outdoor unit to be operated for defrosting operation, the switching valve 22 is switched so that the high-temperature refrigerant gas passes through the hot gas bypass circuit 23A. Means for passing the refrigerant gas to the hot gas bypass circuit 23A may be other means.

FIG. 2 shows an air conditioner according to a second embodiment using another means. In FIG. 2, the refrigeration cycle has the same configuration on the indoor unit side as in the first embodiment described above. On the outdoor unit side, a compressor 1, an outdoor heat exchanger 2, an oil separator 3, a four-way valve 4, an accumulator 5, a refrigerant amount regulator 6, a gas bypass control valve 11, an outdoor expansion valve 21,
It consists of a hot gas bypass control valve 25, etc.
The configuration is the same as that of the first embodiment except that a hot gas bypass control valve 25 is provided instead of the outdoor switching valve 22 to configure a hot gas bypass circuit 23. The connection between the outdoor unit and the indoor unit has the same configuration as in the first embodiment. The operation of the heating operation is the same as in the first embodiment.

In the outdoor unit A, the outdoor heat exchanger 2A
When frost is formed on the surface of the
The outdoor blower 7A is stopped, the gas bypass control valve 11A is opened, and a part of the refrigerant discharged from the compressor 1 is partially passed through the gas bypass 13A branched at the outlet side of the oil separator 3 to the accumulator 5A.
After A, return to the compressor 1. At the same time, the hot gas bypass control valve 25A is opened, a part of the high-temperature refrigerant gas is bypassed to the hot gas bypass circuit 23A, and the outdoor heat exchanger 2
Heat exchange with A to defrost the surface. Other operations and effects are the same as those of the first embodiment.

Further, in each of the above-described embodiments, the outdoor unit to be subjected to the defrosting operation opens the gas bypass control valve 11 during the defrosting operation, so that the high-temperature and high-pressure discharged from the compressor 1 is opened. A part of the refrigerant gas passes through the gas bypass flow rate adjusting throttle device 12 and the gas bypass circuit 13 and is bypassed to the low-pressure gas pipe just before the accumulator 5. By using this control, in the outdoor unit during the defrosting operation, the dryness of the low-temperature low-pressure refrigerant gas returning to the compressor 1 and the superheat degree of the discharged refrigerant gas are secured, and the reliability of the compressor can be improved. it can.

[0022]

According to the present invention, in a heat pump type air conditioner in which an indoor unit and a plurality of outdoor units are connected by the same piping system to constitute a refrigeration cycle, at least one air conditioner is operated during a heating operation. When one of the outdoor units is in a state to be subjected to the defrosting operation, the refrigerant from the hot gas bypass circuit and the common liquid pipe to the outdoor heat exchanger of the outdoor unit to be subjected to the defrosting operation from the outdoor unit to be subjected to the defrosting operation. By performing the defrosting operation with the refrigerant, the amount of the refrigerant circulating to the outdoor heat exchanger to be defrosted is ensured, and a good defrosting operation can be performed. When it is determined that the refrigerant circulation amount of the outdoor unit to be defrosted is large, the appropriate refrigerant circulation amount is secured by flowing the refrigerant from the outdoor unit to be defrosted to another outdoor unit to be heated. it can.

[Brief description of the drawings]

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

FIG. 2 is a refrigerant circuit diagram showing a second embodiment of the air conditioner according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Outdoor heat exchanger 3 Oil separator 4 Four-way valve 5 Accumulator 6 Refrigerant amount regulator 7 Blower for outdoor heat exchanger 8 Indoor heat exchanger 9 Blower for indoor heat exchanger 10 Indoor expansion valve 11 Gas bypass control valve 12 Gas Throttle device for bypass flow rate adjustment 13 Gas bypass circuit 14 Check valve 15 Oil control valve 16 Throttle device for oil flow rate adjustment 17 Oil return pipe 18 Oil leveling pipe 19 Shared gas pipe 20 Shared liquid pipe 21 Outdoor expansion valve 22 Switching valve 23 Hot gas Bypass circuit 24 Low pressure equalizing pipe (for switching valve operation) 25 Hot gas bypass control valve 26 Hot gas bypass flow rate adjusting throttle device 27 Refrigerant control valve

Claims (4)

[Claims] 1. An indoor unit comprising at least one indoor unit having an indoor heat exchanger and an indoor expansion valve, and a plurality of outdoor units having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve. A refrigeration cycle in which the refrigerant discharged from the compressor during heating passes through the four-way valve, the indoor heat exchanger, the indoor expansion valve, the outdoor expansion valve, and the outdoor heat exchanger, and returns to the compressor via the four-way valve. -In a two-pump air conditioner, each outdoor unit is provided with a switching valve on the outlet side of the compressor, and a hot gas bypass circuit connected from the switching valve to the inlet side of the outdoor heat exchanger, and one of the plurality of outdoor units is provided. When the air conditioner is ready for defrosting operation, the outdoor unit to be operated for defrosting operates the switching valve to guide the high-temperature refrigerant gas from the compressor to the outdoor heat exchanger via the hot gas bypass circuit, An air conditioner characterized in that control is performed so that a part of the refrigerant returning from the heat exchanger is guided to an outdoor heat exchanger via an outdoor expansion valve. 2. The air conditioner according to claim 1, further comprising: a connecting pipe connecting the compressor entrance sides of adjacent outdoor units, and a refrigerant control valve provided at both ends of the pipe. An air conditioner characterized by controlling a part of the refrigerant gas returning to the compressor in the indoor unit in the defrosting operation to move to the outdoor unit in the heating operation through the connection pipe by opening the connection pipe. 3. An at least one indoor unit having an indoor heat exchanger and an indoor expansion valve, and a plurality of outdoor units having a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve. A refrigeration cycle in which the refrigerant discharged from the compressor during heating passes through the four-way valve, the indoor heat exchanger, the indoor expansion valve, the outdoor expansion valve, and the outdoor heat exchanger, and returns to the compressor via the four-way valve. -In a two-pump air conditioner, each outdoor unit is provided with a hot gas bypass circuit that branches from the compressor outlet side and is connected to the outdoor heat exchanger inlet side and that includes a bypass control valve, and is provided with one of a plurality of outdoor units. When the defrosting operation is required, the outdoor unit to be defrosted operates the bypass control valve to guide the high-temperature refrigerant gas from the compressor to the outdoor heat exchanger via the hot gas bypass circuit. An air conditioner that controls the refrigerant returning from the indoor unit together with the outdoor heat exchanger through an outdoor expansion valve. 4. The air conditioner according to claim 3, wherein a connection pipe for connecting the compressor entrance sides of adjacent outdoor units is provided, and a refrigerant control valve is provided at both ends of the pipe. An air conditioner characterized by controlling a part of the refrigerant gas returning to the compressor in the indoor unit in the defrosting operation to move to the outdoor unit in the heating operation through the connection pipe by opening the connection pipe.