JP5673290B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner that avoids or suppresses frost formation on an outdoor heat exchanger during heating operation.

  Usually, an air conditioner performs heating operation when the outside air temperature is low. During the heating operation, the outdoor heat exchanger functions as an evaporator, and a low-temperature refrigerant flows. For this reason, moisture contained in the outside air adheres to the outdoor heat exchanger and frost formation occurs. In particular, the lower part of the outdoor heat exchanger is liable to frost due to the small amount of ventilation and the influence of water accumulated at the bottom of the outdoor unit.

  As a technique for suppressing frost formation in the lower part of the outdoor heat exchanger 5, there is one described in Japanese Patent Laid-Open No. 6-323684. As shown in FIG. 5, this prior art prevents frost formation of the subcool heat exchanger 11 disposed at the lower part of the outdoor heat exchanger 5. In order to prevent frost formation, a pipe that bypasses the outlet pipe and the inlet pipe of the subcool heat exchanger 11 is provided so that the refrigerant does not flow through the subcool heat exchanger 11 during heating operation. Thereby, since the refrigerant does not exchange heat with the outside air in the subcool heat exchanger 11, frost formation hardly occurs in the subcool heat exchanger 11.

JP-A-6-323684

  In the air conditioner of Patent Document 1, since the subcool heat exchanger 11 is connected in series with the outdoor heat exchanger 5, it can be bypassed. In order to suppress the frost formation of the outdoor heat exchanger 5 by introducing the technique described in Patent Document 1, a heat exchanger at a location where frost formation is likely to occur is replaced with a heat exchanger different from the outdoor heat exchanger 5. In addition, a complicated structure such as a bypass pipe is required. For this reason, there is a problem that the installation location is limited. Moreover, the frost formation of the path which is a pipe through which the refrigerant passed through the outdoor heat exchanger 5 flows could not be suppressed.

  Therefore, the present invention provides an air conditioner that aims to suppress frost formation in an outdoor heat exchanger by adjusting the flow rate of refrigerant flowing through a portion where frost formation is likely to occur with a simple configuration. Is.

  In order to achieve the above object, the air conditioner of the present invention changes the flow direction of the refrigerant in a predetermined path among paths existing between an outdoor heat exchanger having a plurality of paths and a flow divider. It is equipped with a check valve to limit. In addition, a check valve may be provided in a predetermined path among a plurality of paths existing between the refrigerant pipe connected to the four-way valve and the outdoor heat exchanger. An electromagnetic valve that controls the flow rate of the refrigerant may be used instead of the check valve.

  According to the air conditioner of the present invention, during the cooling operation, the refrigerant can be efficiently condensed by exchanging heat in the entire outdoor heat exchanger. Moreover, at the time of heating operation, the frost formation of the outdoor heat exchanger can be suppressed by stopping the flow of the refrigerant flowing through the path where frost formation easily occurs or reducing the flow rate.

It is the figure which showed the refrigerating cycle of the air conditioner of this invention. It is the figure which showed the outdoor heat exchanger and shunt of the air conditioner of this invention. It is sectional drawing which showed the top blowing type outdoor unit. It is the figure of another Example which showed the outdoor heat exchanger and shunt of the air conditioner of this invention. It is the figure which showed the refrigerating cycle of the air conditioner of a prior art.

  An air conditioner according to an embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1, an air conditioner of the present invention includes a compressor 1 that compresses refrigerant, an indoor heat exchanger 2 that exchanges heat with room air, an expansion valve 3 that is a throttling device, and a refrigerant that is divided into a plurality of paths. And a refrigerant circuit that sequentially circulates the refrigerant. The direction of the refrigerant flowing through the refrigerant circuit is switched by the four-way valve 6, and during the heating operation, the compressor 1, the indoor heat exchanger 2, the flow divider 4, the expansion valve 3, the outdoor heat exchanger 5, the compressor 1 and the refrigerant sequentially. Circulate. In the cooling operation, the refrigerant is sequentially circulated through the compressor 1, the outdoor heat exchanger 5, the flow divider 4, the expansion valve 3, the indoor heat exchanger 2, and the compressor 1. Each is connected by a refrigerant pipe 12.

  In the outdoor heat exchanger 5, the refrigerant flow path of the outdoor heat exchanger 5 is configured by a plurality of paths in order to improve heat exchange efficiency. In order to appropriately divert the refrigerant to the plurality of paths of the outdoor heat exchanger 5, the refrigerant diverter 4 is installed between the outdoor heat exchanger 5 and the expansion valve 3. In order to suppress the frost formation of the outdoor heat exchanger, as shown in FIG. 2, a check is made on a predetermined path, which will be described later, out of a plurality of paths 9 of the outdoor heat exchanger 5 on the shunt 4 side. Valve 7 is installed. In order to prevent refrigerant from flowing into the path (9A, 9B) in which the check valve 7 is installed during heating operation, the check valve 7 is directed in the direction of the arrow of the check valve 7 in FIG. The flow of the refrigerant is limited so that the refrigerant flows only in the direction from the heat exchanger 5 toward the flow divider 4).

  Next, a method for selecting a path for arranging the check valve 7 in order to suppress frost formation on the outdoor heat exchanger 5 will be described.

  In selecting a path for arranging the check valve 7, a heating operation is performed in advance in a low ambient temperature environment using an actual machine, a path where frost formation is actually likely to be extracted, and the path where the check valve 7 is arranged. And

  When the flow rate of refrigerant flowing through the path is the same, frosting tends to occur more easily in the path where the wind speed of the air passing through the path is slow, and the air speed of the air passing through the path is the same. In some cases, frosting tends to occur more easily in a path having a larger flow rate of refrigerant flowing in the path. Thus, the ease of frost formation is affected by the wind speed of the air passing through the path and the flow rate of the refrigerant flowing through the path. Here, the wind speed of the air passing through the path is related to the distance to the blower fan 8. The further away from the blower fan 8, the weaker the suction force of the blower fan 8, and the wind speed of the air passing through the path becomes slower. In general, if the flow rate of refrigerant is substantially the same, frosting is more likely to occur as the wind speed of the passing air is slower.

  The procedure for installing the check valve 7 in a path where frosting is likely to occur will be described using an up-blowing outdoor unit as shown in FIG. 3 as an example. The top-blowing type outdoor unit is arranged at the upper part of the outdoor unit so that the blower fan 8 sends wind upward from below, and the outdoor heat exchanger 5 is arranged below the blower fan 8. The path 9 </ b> A disposed at the lower portion of the outdoor heat exchanger 5 is a path disposed farthest from the blower fan 8, and the suction force by the blower fan 8 is small. This path 9A is a path with a slow wind speed in the outdoor heat exchanger 5. Therefore, as shown in FIG. 2, a check valve 7 is installed in the path 9A to suppress frost formation.

  During the heating operation, the refrigerant flowing into the flow divider 4 is a gas-liquid two-phase refrigerant. Therefore, a large amount of the liquid-phase refrigerant flows in the gas-liquid two-phase through the path 9B disposed at the bottom of the plurality of paths connected to the single flow divider 4. Thereby, the path 9B is likely to be frosted. Therefore, in order to suppress frost formation in the path 9B, a check valve 7 is also installed in the path 9B.

  Since the check valve 7 is installed as described above, the refrigerant flowing from the indoor heat exchanger 2 to the outdoor heat exchanger 5 through the flow divider 4 during the heating operation passes through the check valve 7. Inflow to (9A, 9B) is blocked. Thereby, since a refrigerant | coolant does not distribute | circulate through the path | pass 9A and the path | pass 9B, frost formation can be suppressed. Furthermore, since the check valve 7 is used in the present embodiment, a control mechanism for stopping the refrigerant flow is not necessary.

  On the other hand, during the cooling operation, the refrigerant flowing through the path (9A, 9B) in which the check valve 7 is provided from the outdoor heat exchanger 5 to the indoor heat exchanger 2 via the flow divider 4 flows through the check valve 7. Since it flows in the forward direction, it passes through the check valve 7 and flows to the flow divider 4. Thereby, since a refrigerant | coolant distribute | circulates to all the paths of the outdoor heat exchanger 5, it can heat-exchange with air by all the paths. Therefore, the air conditioner of the present invention can perform an efficient cooling operation.

  Next, the operation of the air conditioner of the present invention will be described. During the cooling operation, the gas refrigerant is compressed by the compressor 1 and discharged as a high-temperature and high-pressure gas refrigerant, and passes through the four-way valve 6 and all the paths including the check valve 7 of the outdoor heat exchanger 5 (9A, 9B). Flows into the path. The refrigerant flowing into the outdoor heat exchanger 5 is condensed by exchanging heat with the outside air. The condensed refrigerant merges at the flow divider 4. The merged refrigerant is reduced in pressure by the expansion valve 3 to become a gas-liquid two-phase refrigerant. This gas-liquid two-phase refrigerant flows into the indoor heat exchanger 2 and evaporates by exchanging heat with the room air to become a low-pressure gas refrigerant. The gas refrigerant returns to the compressor 1 through the four-way valve 6.

  On the other hand, during the heating operation, the gas refrigerant is compressed by the compressor 1 and discharged as a high-temperature and high-pressure gas refrigerant, and flows into the indoor heat exchanger 2 through the four-way valve 6. The refrigerant flowing into the indoor heat exchanger 2 is condensed by exchanging heat with the indoor air. The condensed refrigerant becomes a gas-liquid two-phase refrigerant by being decompressed by the expansion valve 3. This gas-liquid two-phase refrigerant is divided into a plurality of paths 9 by the flow divider 4. The refrigerant does not flow through the check valve 7 in the paths (9A, 9B) in which the check valve 7 is provided. The gas-liquid two-phase refrigerant flowing through a plurality of paths where the check valve 7 is not provided flows into the outdoor heat exchanger 5 and evaporates by exchanging heat with the outside air to become a low-pressure gas refrigerant. The gas refrigerant merges in the refrigerant pipe 12 and returns to the compressor 1 through the four-way valve 6. Since the refrigerant does not flow through the paths (9A, 9B) where the check valve 7 is provided, frost formation on the paths (9A, 9B) can be suppressed. In the present embodiment, the gas refrigerant is merged in the refrigerant pipe 12, but the present invention is not limited to this. The flow divider 4 may be provided on the outlet side of the outdoor heat exchanger 5, and the gas refrigerant may be merged by the flow divider 4 and then flow into the refrigerant pipe 12.

  The defrosting operation performed during the heating operation is the same refrigeration cycle as in the cooling operation. Therefore, high-temperature and high-pressure refrigerant flows through all the paths of the outdoor heat exchanger 5. Therefore, since the high-temperature and high-pressure refrigerant also flows in the paths (9A, 9B) through which the refrigerant does not flow by the check valve 7 during the heating operation, the entire outdoor heat exchanger 5 including the paths (9A, 9B) is defrosted. be able to.

  In addition to the above-described outdoor type outdoor unit, there is an outdoor unit in which the blower fan 8 is installed at a position facing the side surface of the outdoor heat exchanger 5, such as a household outdoor unit. In this outdoor unit, since the paths arranged on the upper side and the lower side of the outdoor heat exchanger 5 are far from the blower fan 8, the path may be a path with a low wind speed. In this case, the check valve 7 is preferably installed in a path with a low wind speed disposed at the upper part and the lower part of the outdoor heat exchanger 5. The present invention is not limited to the above-described embodiment, and is not installed in a path where frost formation is likely to occur during heating operation. Arbitrary paths can be appropriately arranged.

  In the present embodiment, the check valve 7 is provided between the outdoor heat exchanger 5 and the flow divider 4, but the present invention is not limited to this, and as shown in FIG. You may provide in predetermined path | pass (10A, 10B) among the several path | pass 10 of the outdoor heat exchanger 5 in the refrigerant | coolant piping 12 side in the inlet side in case 5 functions as a condenser. From the above, the check valve 7 can be freely arranged in the plurality of paths (9, 10) according to the configuration of the parts.

  In the present embodiment, the check valve 7 is used. However, the present invention is not limited to this, and an electromagnetic valve that can control the refrigerant flow rate is used instead of the check valve 7 so that the refrigerant is not heated. The flow may be stopped or the flow rate of the refrigerant may be reduced to a range where frost formation can be suppressed based on the outside air temperature and the temperature of the outdoor heat exchanger 5. By using the electromagnetic valve, a small amount of refrigerant can be flowed without stopping, the decrease in the amount of heat exchange in the outdoor heat exchanger 5 can be reduced, and the decrease in heating capacity can be suppressed.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Indoor heat exchanger 3 Expansion valve 4 Splitter 5 Outdoor heat exchanger 6 Four way valve 7 Check valve 8 Blower fan 9, 9A, 9B, 9C, 9D path 10, 10A, 10B, 10C, 10D path 11 Subcool heat exchanger 12 Refrigerant piping

Claims (2)

In an air conditioner in which a refrigerant circuit is configured by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a throttling device, a shunt, and an outdoor heat exchanger having a plurality of paths through a refrigerant pipe.
In the heating operation, a check valve is provided on at least one of the inlet side and the outlet side during the heating operation of the path so that the refrigerant does not flow into the path that easily frosts during the heating operation. Air conditioner. In an air conditioner in which a refrigerant circuit is configured by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a throttling device, a shunt, and an outdoor heat exchanger having a plurality of paths through a refrigerant pipe.
An electromagnetic valve is provided on at least one of the inlet side and the outlet side during heating operation of the path so that the refrigerant does not flow into the path that easily frosts during heating operation during the heating operation. Air conditioner to do.

Images