JP2001004234A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alleviate a decrease in a cooling capability when a high-pressure rise is suppressed when cooled by an air conditioner. SOLUTION: In this air conditioner, a bypass pipeline 12 for bypassing a refrigerant from a high pressure side to a low pressure side is arranged to pass the vicinity of normal refrigerant piping 15 in an outdoor heat exchanger 2. When a high-pressure sensor 5 provided at a discharge side of a compressor 1 detects an excessive rise of a pressure, an electronic linear expansion valve 8 and a solenoid valve 9 are opened, the pipeline 12 becomes a communicating state, and a part of a liquid state refrigerant output from the exchanger 2 is bypassed to the low pressure side through the pipeline 12. Thus, an amount of the refrigerant passing an ordinary refrigerant pipeline is reduced, and a pressure rise of the high pressure side is suppressed. Since the bypassed refrigerant deprives the refrigerant of the ordinary refrigerant piping of the exchanger 2 of heat, the degree of supercooling of the refrigerant output from the exchanger 2 is enhanced. Thus, a decrease in a cooling capability due to a reduction in the amount of the circulating refrigerant is alleviated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a refrigerant circuit,
The present invention relates to an air conditioner that can switch between a cooling operation and a heating operation by switching a four-way valve.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a refrigerant circuit of a conventional air conditioner. This air conditioner is of a type that can switch between the cooling operation and the heating operation by switching the connection of the four-way valve 7. This air conditioner has a compressor 1
A bypass pipe 13 is provided from the high-pressure output side to a pipe between the expansion valve 3 and the indoor heat exchanger 4, and the bypass pipe 13 is provided with a bypass solenoid valve 11. The arrow shown in the figure indicates the direction of the flow of the refrigerant.

During the cooling operation, the four-way valve 7 is in the connection state shown in FIG. 5, and the refrigerant compressed by the compressor 1 is liquefied in the outdoor heat exchanger 2 by heat exchange with the outside air. This refrigerant is decompressed by the expansion valve 3 and vaporized by the indoor heat exchanger 4, thereby removing heat from the indoor air and cooling the room. The vaporized refrigerant reaches the compressor 1 through the four-way valve 7, where it is compressed and again reaches the outdoor heat exchanger 2.

During the cooling operation, when the heat exchangers 4 and 2 become dirty or the outdoor temperature rises, the refrigerant is supplied from the high pressure side of the refrigerant circuit, that is, the output of the compressor 1 to the expansion valve 3 via the outdoor heat exchanger 2. In some cases, the pressure in the path leading up to it may be too high. In this conventional apparatus, the high pressure side pressure is monitored by a high pressure sensor 5 provided at the output of the compressor 1, and when the pressure exceeds a predetermined threshold, the bypass solenoid valve 1 is monitored.
By opening 1, a part of the refrigerant on the high pressure side is bypassed to the low pressure side, that is, downstream of the expansion valve 3, and an abnormal rise in pressure on the high pressure side is suppressed.

[0005] In the air conditioner, the connection of the four-way valve 7 is switched during the heating operation, and the high-pressure output from the compressor 1 is liquefied in the indoor heat exchanger 4 to heat the room.

In such a heating operation, if the temperature detected by the pipe temperature sensor 6 provided in the outdoor heat exchanger 2 falls below a predetermined value, and it is determined that frost or ice has adhered to the outdoor heat exchanger 2, Has performed defrosting by switching the connection of the four-way valve 7 to the pattern at the time of the cooling operation and passing the high-temperature refrigerant output from the compressor 1 through the outdoor heat exchanger 2.

[0007]

In the conventional air conditioner, when the pressure on the high pressure circuit side becomes too high during the cooling operation, a part of the high pressure refrigerant is bypassed to the low pressure side. Inside, there is a problem that the amount of the refrigerant passing through the outdoor heat exchanger 2 decreases and the cooling capacity decreases.

Further, in the conventional air conditioner, in the defrosting operation, the four-way valve 7 is switched to the connection for the cooling operation and is operated in the cooling cycle. There was a problem that cold wind blows out.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. First, during cooling operation, an air conditioner capable of suppressing a decrease in cooling capacity and suppressing an increase in pressure on the high-pressure circuit side. The purpose is to provide a machine. Second
Another object of the present invention is to provide an air conditioner that does not blow cold air into a room during a defrosting operation.

[0010]

In order to achieve the above object, an air conditioner according to the present invention is configured such that, when a high pressure sensor detects that the pressure on the high pressure side exceeds a predetermined value, the air conditioner is bypassed. The high-pressure side refrigerant is bypassed to the low-pressure side by opening the on-off valve of the flow path. During this bypass operation, the liquid refrigerant that has exited the outdoor heat exchanger flows into the low pressure side through the vicinity of the refrigerant flow path in the outdoor heat exchanger. Here, the vicinity means that the heat exchanger is in a range in which heat can be exchanged with the refrigerant flow path of the outdoor heat exchanger. With such a configuration, at the time of bypass,
Since the refrigerant passing through the outdoor heat exchanger also performs heat exchange with the liquid refrigerant passing through the bypass flow path, cooling of the high-pressure refrigerant is promoted,
A refrigerant having a higher degree of supercooling than the conventional mechanism is output from the outdoor heat exchanger. Therefore, even if the amount of the circulating refrigerant is reduced by the bypass operation, the decrease in the cooling capacity due to the reduction is reduced by improving the degree of supercooling of the refrigerant.

In a preferred aspect of the present invention, when the pressure measurement value of the high-pressure pressure sensor exceeds the predetermined value, the control valve that opens at a valve opening corresponding to the pressure measurement value is provided in the bypass passage. It was provided between a branch portion between the outdoor heat exchanger and the expansion mechanism and a portion near a refrigerant flow path of the outdoor heat exchanger.

According to this aspect, the higher the pressure, the higher the refrigerant flow rate in the bypass flow path during the bypass operation. Thus, by increasing the amount of the refrigerant to be bypassed in accordance with the increase in the high pressure, the pressure increase can be suppressed efficiently. At this time, if the amount of refrigerant to be bypassed increases, the cooling action of the high-pressure refrigerant in the outdoor heat exchanger also increases, so that a decrease in cooling capacity due to a decrease in the amount of refrigerant flowing through the normal circuit can be suppressed to some extent.

In a preferred aspect of the present invention, a control means for opening the on-off valve when the defrosting operation condition is satisfied during the heating operation is further provided.

In this aspect, when defrosting is performed during the heating operation, the on-off valve is opened to make the bypass flow path conductive, and the high-temperature and high-pressure refrigerant that has exited the compressor flows from the upstream side of the indoor heat exchanger to the downstream side of the outdoor heat exchanger. To the side. By this bypass operation, the high-temperature and high-pressure refrigerant flows near the refrigerant flow path of the outdoor heat exchanger, so that the outdoor heat exchanger is warmed and defrosting is performed. In this aspect, defrosting can be performed while the refrigerant circuit is in the heating operation, so that no cool air is blown into the room during defrosting. In addition, in this mode, the high-pressure suppression and the defrosting operation during the cooling operation can be performed by the same bypass flow path, so that there is an advantage that the device configuration is simplified.

[0015]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 shows a refrigerant circuit during a cooling operation of an air conditioner according to an embodiment of the present invention.

As shown in FIG. 1, the refrigerant circuit of the present embodiment passes through the compressor 1 through the four-way valve 7, the outdoor heat exchanger 2, the expansion valve 3, and the indoor heat exchanger 4 in this order. And a piping path returning to the compressor 1 via the. Between the discharge port of the compressor 1 and the four-way valve 7, a high pressure sensor 5 for monitoring the pressure of the high pressure circuit is provided. The outdoor heat exchanger 2 is provided with a pipe temperature sensor 6 for detecting frost and icing on the refrigerant pipe. When the four-way valve 7 is in the connected state shown in FIG. 1, the refrigerant flows through the pipe in the direction shown by the solid arrow in the figure. Due to such refrigerant circulation, the refrigerant compressed by the compressor 1 is supplied to the outdoor heat exchanger 2.
The refrigerant is liquefied by heat exchange with the outside air, and the liquefied refrigerant is decompressed by the expansion valve 3 and further vaporized by the indoor heat exchanger 4 to remove heat from the indoor air and cool the room.

In the present embodiment, a bypass pipe 12 is provided for connecting a pipe between the outdoor heat exchanger 2 and the expansion valve 3 and a pipe between the indoor heat exchanger 4 and the four-way valve 7. A part of the bypass pipe 12 is connected to the normal refrigerant pipe 1 in the outdoor heat exchanger 2.
5 was passed. This bypass line 12
It is used to suppress an abnormal increase in pressure of the high-pressure side circuit from the compressor 1 to the expansion valve 3 via the outdoor heat exchanger 2. The bypass pipe 12 is provided with an electromagnetic valve 9 controlled by a control mechanism (not shown). The opening and closing of the electromagnetic valve 9 switches the conduction and non-conduction of the bypass pipe 12. Further, a capillary tube 10 is provided straddling the electromagnetic valve 9 to prevent the occurrence of liquid seal in the bypass conduit 12 when the electromagnetic valve 9 is fully closed. An electronic linear expansion valve (hereinafter, referred to as an LEV) 8 is provided in a path from the branch point on the outdoor heat exchanger 2 side of the bypass pipe 12 to the inside of the outdoor heat exchanger 2. The LEV 8 is a valve whose valve opening can be adjusted according to the level of a control signal from the control mechanism, and is used for adjusting the flow rate of the bypass pipe 12.

FIG. 2 is a flow chart showing the flow of the high pressure suppression control during the cooling operation. As shown in the figure, the control mechanism of the air conditioner of the present embodiment constantly monitors the pressure measurement value of the high-pressure pressure sensor 5 and determines whether or not the measurement value exceeds a predetermined value serving as a criterion for determining abnormal pressure rise. Is determined (S10). Here, when it is determined that the measured pressure value is equal to or less than the predetermined value, the pressure of the high-pressure side circuit is within the normal range, and the LEV 8 and the solenoid valve 9 are controlled to be closed (S12). In this case, the refrigerant flows through the normal refrigerant pipe along the solid line arrow in FIG.

On the other hand, if it is determined in S10 that the pressure measurement value of the high pressure sensor 5 is equal to or greater than the predetermined value, the LEV8
Is opened (S14) and the solenoid valve 9 is opened (S16).
Thereby, the bypass pipe 12 becomes conductive, and a part of the liquid refrigerant output from the outdoor heat exchanger 2 is bypassed to the downstream side of the indoor heat exchanger 4 through the bypass pipe 12 (see FIG. 1). The flow indicated by the dashed arrow). As a result, a part of the refrigerant flows through the bypass pipe, the amount of the refrigerant passing through the normal refrigerant pipe decreases, and the pressure increase in the high-pressure side circuit is reduced. In this configuration, the bypassed liquid refrigerant exchanges heat with the refrigerant flowing in the normal refrigerant pipe 15 in the pipe section 12 a inside the outdoor heat exchanger 2, and bypasses the refrigerant in the pipe 15. Cool more than before. Thereby, the degree of supercooling of the liquid refrigerant output from the outdoor heat exchanger 2 increases. Therefore, although the amount of circulating refrigerant in the refrigerant pipe is reduced by the bypass operation, the degree of supercooling of the refrigerant output from the outdoor heat exchanger 2 is increased, so that a decrease in cooling capacity is reduced.

In the present embodiment, in the opening control of the LEV 8 in S14, the valve opening of the LEV 8 is controlled based on the magnitude of the pressure measurement value. That is, the control mechanism includes the LEV8
Is registered as a function of the pressure value of the high-pressure side circuit, and the appropriate valve opening is calculated according to this function. This function is a function that increases as the high pressure value increases. For example, a function proportional to the pressure value can be used. By adjusting the opening of the LEV 8 in accordance with such a function, the higher the pressure on the high pressure side, the greater the amount of refrigerant to be bypassed, and the greater the effect of suppressing pressure rise. In this case, if the pressure measurement increases,
Since the amount of the liquid refrigerant flowing through the pipe portion 12a in the outdoor heat exchanger 2 increases, and the cooling effect of the high-pressure refrigerant flowing through the normal refrigerant pipe 15 increases, the cooling capacity accompanying the decrease in the amount of the refrigerant flowing through the refrigerant circuit is reduced. Can be reduced.

As described above, according to the present embodiment, it is possible to suppress the increase in the pressure of the high-pressure side circuit during the cooling operation while reducing the decrease in the cooling capacity as compared with the related art.

FIG. 3 is a diagram showing a refrigerant circuit during a heating operation of the air conditioner of the present embodiment. During the heating operation, the connection of the four-way valve 7 is switched as shown in FIG. Thereby, the high-pressure refrigerant output from the compressor 1 is transferred to the indoor heat exchanger 4.
And the room is heated by heat exchange in the indoor heat exchanger 4. The liquid refrigerant condensed in the indoor heat exchanger 4 is decompressed by the expansion valve 3, vaporized in the outdoor heat exchanger 2, takes heat from the outside air, returns to the compressor 1, and is compressed again.

FIG. 4 shows a flow of the defrosting operation control during the heating operation. First, the control mechanism of the present air conditioner constantly monitors the temperature measurement value of the pipe temperature sensor 6 and determines whether or not the measured value has exceeded a predetermined value serving as a criterion for frosting / icing (S20). ). Here, when it is determined that the measured temperature value is equal to or less than the predetermined value, it is determined that frost and icing have not occurred, and the LEV 8 and the solenoid valve 9 are controlled to be closed (S22). In this case, the refrigerant flows through the normal refrigerant pipe along the solid arrow in FIG.
Does not flow to

On the other hand, if it is determined in S20 that the measured pressure value of the pipe temperature sensor 6 is equal to or greater than the predetermined value, the LEV8
Is fully opened (S24) and the solenoid valve 9 is opened (S2).
6). Thereby, the bypass pipe 12 becomes conductive, and a part of the high-temperature and high-pressure refrigerant upstream of the indoor heat exchanger 4 is bypassed to the upstream side of the outdoor heat exchanger 2 through the bypass pipe 12 (FIG. 3). Flow indicated by a broken line arrow). As a result, part of the high-temperature and high-pressure refrigerant passes through the pipe portion 12a inside the outdoor heat exchanger 2, and as a result, the outdoor heat exchanger 2 is warmed, and a defrosting effect is obtained.

As described above, in the present embodiment, defrosting can be performed while the heating cycle is being performed, so that cold air does not blow into the room during defrosting.

The preferred embodiment of the present invention has been described above. As is clear from the above description, the air conditioner of the present embodiment realizes the high-pressure suppression during the cooling operation and the defrosting operation without blowing the cool air in the same circuit,
Manufacturing cost can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing a flow of high-pressure suppression control during a cooling operation.

FIG. 3 is a diagram illustrating a refrigerant circuit during a heating operation of the air conditioner according to the embodiment.

FIG. 4 is a flowchart showing a flow of defrosting operation control during a heating operation.

FIG. 5 is a diagram showing a refrigerant circuit of a conventional air conditioner.

[Explanation of symbols]

1 compressor, 2 outdoor heat exchanger, 3 expansion valve, 4 indoor heat exchanger, 5 high pressure sensor, 6 pipe temperature sensor,
7 Four-way valve, 8 Electronic linear expansion valve (LEV), 9
Solenoid valve, 10 capillary tube, 11 solenoid valve for bypass, 12, 13 bypass line.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 24, 1999 (1999.9.2)
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

During the cooling operation, if the outdoor heat exchanger 2 becomes dirty or the outdoor temperature rises, the refrigerant reaches the expansion valve 3 from the high pressure side of the refrigerant circuit, that is, the output of the compressor 1 via the outdoor heat exchanger 2. In some cases, the pressure in the path to the path may rise too much. In this conventional apparatus, the high pressure side pressure is monitored by a high pressure sensor 5 provided at the output of the compressor 1, and when the pressure exceeds a predetermined threshold, the bypass solenoid valve 1 is monitored.
By opening 1, a part of the refrigerant on the high pressure side is bypassed to the low pressure side, that is, downstream of the expansion valve 3, and an abnormal rise in pressure on the high pressure side is suppressed.

Claims (3)

[Claims] A refrigerant circuit that sequentially communicates a compressor, a four-way valve, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger;
An air conditioner capable of switching between a cooling operation and a heating operation by switching a four-way valve. The air conditioner branches from between an outdoor heat exchanger and an expansion mechanism and passes through a route near a refrigerant flow path in the outdoor heat exchanger. A bypass flow path connected between the indoor heat exchanger and the four-way valve; an on-off valve provided in the bypass flow path; and a high-pressure pressure provided between the discharge part of the compressor and the four-way valve. A high-pressure sensor that opens the on-off valve and bypasses the refrigerant output from the outdoor heat exchanger to a downstream stage of the indoor heat exchanger when a pressure measurement value of the high-pressure pressure sensor exceeds a predetermined value during a cooling operation. An air conditioner comprising: a suppression control unit. 2. The outdoor heat exchanger in the bypass passage, wherein a control valve that opens at a valve opening corresponding to the pressure measurement value when the pressure measurement value of the high pressure sensor exceeds the predetermined value. 2. The air conditioner according to claim 1, wherein the air conditioner is provided between a branch portion between the heat exchanger and the expansion mechanism and a portion near a refrigerant flow path of the outdoor heat exchanger. 3. 3. The air conditioner according to claim 1, further comprising a control unit that opens the on-off valve when a defrosting operation condition is satisfied during a heating operation.