JPH09152216A - Air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of a pressure loss at the heat-exchange passage on an outdoor heat-exchanger and lowering of heat-exchange performance. SOLUTION: Heating operation is carried out in such a manner that the flow direction of a refrigerant from a compressor 12 is switched by a four-way valve 15 and the refrigerant flows to an indoor heat-exchanger 16 and an outdoor heat-exchanger 17. The outdoor heat-exchanger 17 is provided in the middle between heat-exchangers 17a and 17b, being one full pass, with a gas liquid separator 22 to separate gas and liquid of a refrigerant from each other in the middle of heat-exchange and a bypass pipe 24 running in such a manner that the separated refrigerant in a gas phase bypasses the heat-exchanger 17b situated downstream and flows in a refrigerant suction flow passage 25 connected to a suction port 14 of the compressor 12. This constitution reduces a ratio of a gas phase content of a refrigerant flowing through the heat- exchanger 17b and prevents the increase of a pressure loss and lowering of heat-exchanger performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner constituted by a refrigeration cycle capable of heating operation.

[0002]

2. Description of the Related Art A conventional example of an air conditioner will be described with reference to FIGS. FIG. 3 is a refrigeration cycle diagram, and FIG. 4 is a schematic side view of the outdoor heat exchanger.

In FIGS. 3 and 4, 1 is a refrigeration cycle of an air conditioner composed of an indoor unit and an outdoor unit, 2 is a compressor, 3 is a four-way valve which is a switching valve, and 4 is a refrigerant parallel flow 2 An indoor heat exchanger 5 having one heat exchange passage 4a, 4b, an expansion valve 5 and an outdoor heat exchanger 6 having three heat exchange passages 6a, 6b, 6c, one end of which is connected to a three-way bend 7. This outdoor heat exchanger 6 includes heat exchange paths 6a, 6
b and 6c are formed by a plurality of heat exchange pipes 9 each penetrating a large number of heat radiation fins 8 and a retanbend 10 connecting the heat exchange pipes 9 so as to meander in sequence.

Then, the heat exchange paths 4a of the indoor heat exchanger 4,
Both of 4b have one end connected to the connection port of the four-way valve 3 and the other end connected to the expansion valve 5. The other end of the heat exchange passage 6a of the outdoor heat exchanger 6 is connected to the expansion valve 5, and the other ends of the heat exchange passages 6b and 6c are connected to the connection port of the four-way valve 3.

With the above construction, when the refrigeration cycle 1 is operated for heating, the four-way valve 3 is switched as shown by the solid line to flow the refrigerant so that the indoor heat exchanger 4 serves as a condenser and the outdoor heat exchange is performed. The vessel 6 functions as an evaporator.
In the cooling operation, the four-way valve 3 is switched as shown by the dotted line to flow the refrigerant in the opposite direction so that the indoor heat exchanger 4 functions as an evaporator and the outdoor heat exchanger 6 functions as a condenser.

In the heating operation, the refrigerant having passed through the expansion valve 5 flows into the outdoor heat exchanger 6 to exchange heat in the heat exchange passage 6a, and then is split by the three-way bend 7 to split the split gas phase. The increased amount of the refrigerant flows into the heat exchange paths 6b and 6c for heat exchange. In this way, by splitting the refrigerant that increases the flow rate by increasing the gas phase content by heat exchange,
The pressure loss inside the heat exchange pipe 9 is prevented from increasing.

However, in the above prior art,
In order to split the refrigerant in the middle of the heat exchange process in the outdoor heat exchanger 6, the refrigerant at the time of this split is in a gas-liquid two-phase state in which the gas and the liquid after heat exchange in the heat exchange passage 6a are mixed, Two heat exchange paths 6b and 6c are split by the three-way bend 7.
It is difficult to flow as a refrigerant having the same gas-liquid mixing ratio.

For example, when the flow rate of the refrigerant flowing through the outdoor heat exchanger 6 is large, the refrigerant flows through the heat exchange pipe 9 at a high speed, so that the heat exchange path 6a is diverted by the three-way bend 7 and the heat exchange path 6b. , 6c, the gas-liquid mixing ratios of the refrigerants are almost the same because the gas-liquid mixing is substantially uniform in the flow. However, the outdoor heat exchanger 6
When the flow rate of the refrigerant flowing through is small, the refrigerant flows in the heat exchange pipe 9 at a low speed, which causes a distribution in the way the gas and the liquid are mixed in the flow, and the refrigerant is divided by the three-way bend 7. At this time, the gas-liquid mixing ratio of the split refrigerant is unbalanced, and the gas-liquid mixing ratio of the refrigerant flowing through the two heat exchange paths 6b and 6c becomes different.

When the gas-liquid mixing ratios of the refrigerants in the two heat exchange paths 6b and 6c are different, each heat exchange path 6
The heat exchange states of b and 6c are different, and the heat exchange performance of the outdoor heat exchanger 6 as a whole is deteriorated. Further, in the refrigerant flow path from the outdoor heat exchanger 6 to the suction port of the compressor 2, the refrigerant having the increased vapor phase flows, the pressure loss in the flow path increases, and the operation efficiency of the refrigeration cycle 1 decreases. Becomes

[0010]

As described above, in the prior art, the refrigerant is diverted during the heat exchange process in order to prevent an increase in pressure loss inside the pipe in the heat exchange passage of the outdoor heat exchanger. However, it is difficult to maintain the same gas-liquid mixing ratio of the refrigerant in each of the divided heat exchange passages, resulting in poor heat exchange performance in the outdoor heat exchanger. In the refrigerant flow path in which the refrigerant is sucked from the exchanger to the compressor, pressure loss increases and efficiency decreases. The present invention has been made in view of such a situation, an increase in pressure loss and a decrease in heat exchange performance in the heat exchange passage of the outdoor heat exchanger,
Another object of the present invention is to provide an air conditioner that prevents an increase in pressure loss in the refrigerant flow path from the outdoor heat exchanger to the compressor.

[0011]

An air conditioner according to the present invention comprises:
In the air conditioner in which the refrigerant discharged from the compressor is circulated by circulating the refrigerant through the indoor heat exchanger and the outdoor heat exchanger, the outdoor heat exchanger has an intermediate heat exchange path in the middle of the heat exchange path. With a gas-liquid separator for separating the refrigerant into a gas and a liquid, the refrigerant in the gas phase separated by the gas-liquid separator is provided with a bypass pipe that bypasses the downstream heat exchange path. In addition, in the air conditioner in which the refrigerant discharged from the compressor is switched in the direction of flow by the switching valve and circulated by flowing through the indoor heat exchanger and the outdoor heat exchanger to perform cooling operation or heating operation. The heat exchanger has a gas-liquid separator in the middle of the heat exchange path for separating the refrigerant in the middle of heat exchange into gas and liquid, and the refrigerant in the gas phase separated by the gas-liquid separator during the heating operation is the heat of the downstream side. Equipped with a bypass pipe that bypasses the exchange path Furthermore, the bypass pipe is configured such that the refrigerant in the gas phase separated by the gas-liquid separator flows into the refrigerant passage between the switching valve and the suction port of the compressor. Further, the bypass pipe is characterized in that an opening / closing valve is inserted in an intermediate portion, and further, the opening / closing valve inserted in the bypass pipe is In the heating operation, when the operating frequency of the compressor is lowered and the refrigerant flow rate becomes a predetermined flow rate or less, the closing operation is performed, and the opening / closing valve inserted in the bypass pipe is used in the cooling operation. It is characterized by being a closing operation.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 1 is a refrigeration cycle diagram, and FIG. 2 is a schematic side view of an outdoor heat exchanger.

In FIG. 1 and FIG. 2, 11 is a refrigeration cycle of an air conditioner constituted by an indoor unit installed in an air-conditioned room and an outdoor unit installed outdoors. This refrigeration cycle 11 includes a compressor 12 and Compressor 1
The four-way valve 15 which is a switching valve connected to the discharge port 13 and the suction port 14 of No. 2, the indoor heat exchanger 16 and the outdoor heat exchanger 17 connected to the four-way valve 15, the indoor heat exchanger 16 and the outdoor heat The expansion valve 18 is inserted between the exchanger 17 and the exchanger 17.

During the heating operation, the refrigerant is compressed by the compressor 1.
2 is discharged from the discharge port 13 and flows from the four-way valve 15 to the indoor heat exchanger 16, the expansion valve 18, and the outdoor heat exchanger 17,
The four-way valve 15 circulates so as to be sucked again into the suction port 14 of the compressor 12. Further, during the cooling operation, the four-way valve 15 is switched, the refrigerant is discharged from the discharge port 13 of the compressor 12, and from the four-way valve 15, the outdoor heat exchanger 17 and the expansion valve 18 are reversed.
Further, it circulates so as to flow with the indoor heat exchanger 16 and be sucked again from the four-way valve 15 into the suction port 14 of the compressor 12.

The indoor heat exchanger 16 is provided with heat exchange passages 16a and 16b formed by penetrating a plurality of heat exchange pipes through a large number of radiating fins (not shown) and through which two refrigerants flow in parallel. Both ends of the passages 16a and 16b are connected to each other, a connecting portion on one end side is connected to the four-way valve 15, and a connecting portion on the other end side is connected to the expansion valve 18. In addition, the outdoor heat exchanger 17
Is a plurality of heat exchange pipes 20 penetrating a large number of rectangular heat radiation fins 19 and a retanbend 21 that connects the heat exchange pipes 20 so as to meander in sequence.
Two heat exchange paths 17a and 17b are formed separately on both sides in the longitudinal direction of the radiation fin 19.

Reference numeral 22 is a gas-liquid separator.
The two connection ports 22a and 22b are connected between one ends of the heat exchange pipes 20 forming the heat exchange passages 17a and 17b of the outdoor heat exchanger 17, and the two heat exchange passages 17a and 1b are connected.
It is inserted in series so that the liquid-phase refrigerant flows between 7b. The gas-phase separator outlet 22c of the gas-liquid separator 22 is connected to one end of a bypass pipe 24 in which an electromagnetic valve 23, which is an opening / closing valve, is inserted in the middle portion, and the other end of the bypass pipe 24 is a four-way valve. The suction port 14 side is connected to a refrigerant suction flow path 25 that connects between 15 and the suction port 14 of the compressor 12. It should be noted that the solenoid valve 23 is open during the normal heating operation, and the operating frequency of the compressor 12 is low even during the heating operation, and the flow rate of the circulating refrigerant is equal to or lower than a predetermined flow rate, or when the cooling operation is performed. Is closed and all the refrigerant flows through the heat exchange paths 17a and 17b of the outdoor heat exchanger 17.

During the heating operation, the refrigerant flowing through the heat exchange passage 17a on the upstream side of the outdoor heat exchanger 17 and being in a gas-liquid mixed state by heat exchange passes through the gas-liquid separator 22 and is vaporized. And a liquid phase component, and the separated liquid phase refrigerant flows into the downstream heat exchange passage 17b.
In addition, the gas-phase refrigerant separated from the gas-phase component discharge port 22c of the gas-liquid separator 22 bypasses the heat exchange passage 17b and the four-way valve 15 on the downstream side by the bypass pipe 24 so that the compressor 12 of the compressor 12 is closed. It is designed to flow to the suction port 14.

With the above-described structure, when the refrigeration cycle 11 is operated for heating, the four-way valve 15 is switched as shown by the solid line to flow the refrigerant, whereby the indoor heat exchanger 1 is operated.
6 functions as a condenser, and the outdoor heat exchanger 17 functions as an evaporator. Further, when performing the cooling operation, the indoor heat exchanger 16 functions as an evaporator and the outdoor heat exchanger 17 functions as a condenser by switching the four-way valve 15 as shown by the dotted line and flowing the refrigerant in the opposite direction.

In the normal heating operation, the refrigerant that has passed through the expansion valve 18 from the indoor heat exchanger 16 flows into the outdoor heat exchanger 17, and the heat exchange in the upstream heat exchange passage 17a causes gas-liquid The mixture is brought into a mixed state, and then the refrigerant in a state in the middle of the heat exchange process flows into the gas-liquid separator 22 from the connection port 22a and is separated into a gas phase component and a liquid phase component. Then, the separated liquid-phase refrigerant flows from the gas-liquid separator 22 through the connection port 22b to the heat exchange passage 17b on the downstream side, and again the heat exchange passage 17b.
Is efficiently heat-exchanged into a gas-phase state and flows into the four-way valve 15, further flows from the four-way valve 15 through the refrigerant suction flow path 25, and is sucked into the compressor 12 through the suction port 14. On the other hand, the gas-phase refrigerant separated by the gas-liquid separator 22 is the gas-phase component discharge port 22.
When the solenoid valve 23 is in the open state, the heat exchange passage 1 on the downstream side flows into the bypass pipe 24 in which the solenoid valve 23 is inserted.
7b and the four-way valve 15 are bypassed, the refrigerant flows directly into the refrigerant suction passage 25, and is sucked into the compressor 12 through the suction port 14.

As a result, in the normal heating operation, the refrigerant in the gas-liquid mixed state by heat exchange in the heat exchange passage 17a of the outdoor heat exchanger 17 is removed in the gas-phase separator 22. As a result, heat exchange is performed in the heat exchange passage 17b with a large amount of liquid phase, the flow velocity of the refrigerant in the pipe does not become high, and an increase in pressure loss is suppressed, and heat exchange with the heat exchange passage 17a is suppressed. The passages 17b are connected in series so as to form one path in the refrigerant circulation direction, and it is possible to prevent a decrease in heat exchange performance that occurs due to the flow of the refrigerant.

Further, the gas-phase refrigerant separated by the gas-liquid separator 22 directly flows into the refrigerant suction passage 25 communicating with the suction port 14 of the compressor 12, bypassing the heat exchange passage 17b and the four-way valve 15. As a result, the outdoor heat exchanger 17
The pressure loss from the compressor to the suction port 14 of the compressor 12 is reduced, and the operation efficiency of the refrigeration cycle 11 is improved.

Further, even in the heating operation, when the compressor 12 in which the flow rate of the refrigerant decreases and operates at an operating frequency lower than a predetermined frequency, the solenoid valve 23 is closed and the entire amount of the refrigerant is in the outdoor heat exchanger. Even after 17 is separated into gas and liquid by the gas-liquid separator 22, the outdoor heat exchanger 17
The heat exchange performance is not lowered by increasing the flow velocity in the pipe without reducing the flow rate of the refrigerant in the above. When the cooling operation is further performed, the solenoid valve 23 is closed,
The entire amount of the refrigerant flows through the outdoor heat exchanger 17 to perform heat exchange so that the heat exchange performance does not deteriorate.

[0023]

As is apparent from the above description, the present invention has a gas-liquid separator for separating the refrigerant in the middle of heat exchange into gas and liquid in the middle of the one-pass heat exchange passage of the outdoor heat exchanger, and By providing a bypass pipe that bypasses the gas-phase refrigerant separated by the gas-liquid separator, an increase in pressure loss in the heat exchange path of the outdoor heat exchanger during the heating operation of the refrigerant and heat exchange performance There is an effect such that the reduction can be prevented.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram showing an embodiment of the present invention.

FIG. 2 is a schematic side view of the outdoor heat exchanger according to the embodiment of the present invention.

FIG. 3 is a refrigeration cycle diagram of a conventional example.

FIG. 4 is a schematic side view of an outdoor heat exchanger of a conventional example.

[Explanation of symbols]

 11 ... Refrigeration cycle 12 ... Compressor 14 ... Suction port 15 ... Four-way valve 16 ... Indoor heat exchanger 17 ... Outdoor heat exchangers 17a, 17b ... Heat exchange path 22 ... Gas-liquid separator 23 ... Solenoid valve 24 ... Bypass pipe 25 ... Refrigerant suction passage

Claims (6)

[Claims] 1. An air conditioner in which a refrigerant discharged from a compressor is circulated by circulating the refrigerant through an indoor heat exchanger and an outdoor heat exchanger, wherein the outdoor heat exchanger comprises:
In the middle of the heat exchange path, a gas-liquid separator that separates the refrigerant in the middle of heat exchange is separated, and the refrigerant in the gas phase separated by the gas-liquid separator bypasses the heat exchange path on the downstream side. An air conditioner characterized by having a bypass pipe. 2. An air conditioner in which a refrigerant discharged from a compressor is switched to a circulation direction by a switching valve to flow through an indoor heat exchanger and an outdoor heat exchanger and circulated so that a cooling operation or a heating operation can be performed. The outdoor heat exchanger has a gas-liquid separator for gas-liquid separating the refrigerant in the middle of heat exchange in the middle of the heat exchange path, and the refrigerant in the gas phase separated by the gas-liquid separator during the heating operation is An air conditioner comprising a bypass pipe that bypasses the heat exchange path on the downstream side. 3. The bypass pipe is provided so that the gas-phase refrigerant separated by the gas-liquid separator flows into the refrigerant flow path between the switching valve and the suction port of the compressor. The air conditioner according to claim 2. 4. The air conditioner according to claim 2, wherein an opening / closing valve is inserted in an intermediate portion of the bypass pipe. 5. The on-off valve inserted in the bypass pipe is closed when the operating frequency of the compressor is lowered during heating operation and the refrigerant flow rate is below a predetermined flow rate. Air conditioner. 6. The air conditioner according to claim 4, wherein the on-off valve inserted in the bypass pipe is closed during the cooling operation.