JP5404489B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner capable of heating operation, and more particularly to an air conditioner having a defrosting operation function.

  In the heating operation of the air conditioner, the temperature of the outdoor heat exchanger decreases as the outside air temperature decreases, so that moisture in the outside air becomes frost and adheres to the outdoor heat exchanger. When the heating operation is continued in this state, frost formed on the heat exchanger gradually grows to hinder the heat exchange performance of the outdoor heat exchanger, and the heating capacity is reduced.

  In order to prevent a reduction in heating capacity, it is common to detect the frost formation of the outdoor heat exchanger and perform an operation for melting the frost (hereinafter referred to as a defrosting operation). This defrosting operation switches the refrigeration cycle from the heating cycle to the cooling cycle by switching the four-way valve, stops the blower of the indoor unit and the outdoor unit, and converts the high-temperature and high-pressure gas refrigerant discharged from the compressor into the outdoor heat exchanger The frost attached to the outdoor heat exchanger is melted by flowing through

  However, during the defrosting operation, in addition to not being able to demonstrate the heating capacity, the indoor heat exchanger becomes an evaporator and its temperature decreases, so it takes time for warm air to blow out in the heating operation after the defrosting operation. This reduces the comfort of the indoor space and is one of the complaints about the air conditioner for users.

  Therefore, for example, there is an air conditioner disclosed in Japanese Patent Application Laid-Open No. 11-182994 (Patent Document 1). This air conditioner has a heat pump type refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, an electric expansion valve, and an outdoor heat exchanger are connected by a refrigerant circuit. A part of the high-temperature refrigerant from the section is bypassed to the outdoor heat exchanger, and the frost attached to the outdoor heat exchanger is melted.

JP-A-11-182994

  In the air conditioner described in Patent Document 1, since there is one outdoor heat exchanger path, the defrosting effect is high for the side where the high-temperature refrigerant flows, but the downstream side defrosts. It is difficult to efficiently and uniformly defrost the entire heat exchanger.

  There is also known an air conditioner including an outdoor heat exchanger for exchanging heat by a pipe (path) branched into a plurality of branches, and in such an air conditioner, the compressor on the discharge side of the compressor is also known. It is also considered to defrost by bypassing a part of the high-temperature refrigerant so as to flow through each path of the outdoor heat exchanger. However, because it has multiple paths, the frosting state is different for each path, and the amount of inflow of high-temperature gas (high-temperature refrigerant) that is bypassed from the compressor discharge side and flows into the indoor heat exchanger is also different for each path. Since variations occur every time, there arises a problem that frost on a specific path does not melt. Moreover, in order to melt the frost of all the paths, it is necessary to bypass a large amount of high-temperature gas for defrosting. For this reason, there is a problem that the heating capacity is lowered and the comfort is lowered.

  It is an object of the present invention to perform defrosting operation of an outdoor heat exchanger, air that can efficiently defrost the entire heat exchanger while reducing a bypass flow rate of a high-temperature gas for defrosting and suppressing a decrease in heating capacity. It is to obtain a harmony machine.

In order to achieve the above object, the present invention comprises a compressor, an outdoor heat exchanger, an outdoor expansion valve, and at least an air conditioner capable of heating operation, wherein the outdoor heat exchanger is composed of a plurality of passes. A bypass circuit is provided for connecting the discharge side of the compressor and the inlet side of the outdoor heat exchanger during heating operation, and the bypass circuit includes a bypass electromagnetic valve and is connected to the side connected to the outdoor heat exchanger. Includes a plurality of distribution pipes having capillary tubes, and the plurality of distribution pipes are respectively connected to a plurality of paths of the outdoor heat exchanger, and at least one of the capillary tubes respectively provided in the plurality of distribution pipes is The size is different from other capillary tubes .

Another feature of the present invention is an air conditioner in which a refrigeration cycle is configured by connecting a compressor, a four-way valve, an indoor heat exchanger, an outdoor expansion valve, and an outdoor heat exchanger with a refrigerant pipe. The apparatus includes a plurality of paths, and the liquid refrigerant from the indoor heat exchanger is branched to a plurality of branch pipes after passing through the outdoor expansion valve, and flows into the plurality of paths of the outdoor heat exchanger, respectively. A bypass circuit for branching a part of the high-temperature refrigerant discharged from the compressor and flowing to the inlet side during heating operation of the outdoor heat exchanger, the bypass circuit includes a bypass solenoid valve, and The side connected to the outdoor heat exchanger is composed of a plurality of distribution pipes having capillary tubes, and each of the plurality of distribution pipes is connected to each path of the outdoor heat exchanger, and is provided in each of the plurality of distribution pipes. Capillary Chu At least one or more of the probe is to have a different configuration other capillary tube and size.

Still another feature of the present invention is that a gas connection pipe and a liquid connection pipe connect an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve, and an indoor unit having an indoor heat exchanger and an indoor expansion valve. In the air conditioner configured to be connected with the outdoor heat exchanger, the outdoor heat exchanger has a plurality of paths, and during heating operation, the liquid refrigerant from the indoor unit is branched into a plurality of branch pipes after passing through the outdoor expansion valve. A bypass circuit for causing the high-temperature refrigerant discharged from the compressor to partially branch and flow to the inlet side during heating operation of the outdoor heat exchanger. The bypass circuit is provided with a bypass solenoid valve, and the side connected to the outdoor heat exchanger is constituted by a plurality of distribution pipes having capillary tubes, and is connected to each path of the outdoor heat exchanger. The plurality At least one of each provided with a capillary tube dispensing tube is to have a different configuration other capillary tube and size.
Still another feature of the present invention includes a compressor, an outdoor heat exchanger, an outdoor expansion valve, and at least an air conditioner capable of heating operation, wherein the outdoor heat exchanger includes a plurality of passes, Provided is a bypass circuit that connects the discharge side of the compressor and the inlet side of the outdoor heat exchanger during heating operation. The bypass circuit includes a bypass solenoid valve, and a capillary is provided on the side connected to the outdoor heat exchanger. A plurality of distribution pipes having tubes, the plurality of distribution pipes connected to a plurality of paths of the outdoor heat exchanger, respectively, and temperature detection means for detecting an outdoor temperature; and the outdoor heat exchanger A temperature detecting means for detecting the temperature of the outdoor heat exchanger, and a controller for judging whether or not the outdoor heat exchanger has a possibility of frost formation based on the temperature detected by the temperature detecting means. Being A.

  ADVANTAGE OF THE INVENTION According to this invention, the air which can defrost the whole heat exchanger efficiently, reducing the defrosting operation | movement of an indoor heat exchanger, reducing the bypass flow volume of the high temperature gas for defrosting, and suppressing the fall of heating capability. A harmony machine can be obtained.

The refrigeration cycle block diagram which shows Example 1 of the air conditioner of this invention, The figure which mainly shows the outdoor unit side. The flowchart explaining the defrost operation control in Example 1 of this invention.

  Hereinafter, embodiments of the air conditioner of the present invention will be described with reference to the drawings.

  FIG. 1 is a refrigeration cycle configuration diagram showing Embodiment 1 of an air conditioner of the present invention, and shows an air conditioner 50 mainly on the outdoor unit 51 side. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is an outdoor expansion valve, 11 is a gas blocking valve, 12 is a liquid blocking valve, and 53 is connected to the indoor unit (not shown) side. Similarly, the gas connection pipe 54 is a liquid connection pipe.

  During the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 2, the gas blocking valve 11, and the gas connection pipe 53 as shown by the solid line arrow, reaches the indoor unit, is condensed, and is liquid Becomes a refrigerant. This liquid refrigerant passes through a normally open indoor expansion valve (not shown), then reaches the outdoor expansion valve 4 through the liquid connection pipe 54 and the liquid blocking valve 12, and is decompressed by the outdoor expansion valve 4 to a low temperature. It becomes a low-pressure gas-liquid mixed refrigerant. The decompressed refrigerant is evaporated by the outdoor heat exchanger 3, becomes a gas refrigerant, and returns to the compressor 1 through the four-way valve 2 again.

  The outdoor heat exchanger 3 is constituted by five passes in this embodiment, and the refrigerant after passing through the outdoor expansion valve 4 is distributed by the distributor 20 to the five branch pipes 21 to be 5 of the outdoor heat exchanger 3. Each flows into one path. The refrigerant is evaporated in the outdoor heat exchanger 3, and the refrigerant from each path is collected in the header 22 and flows to the four-way valve 2 side.

  17 is a bypass circuit branched from the refrigerant piping between the discharge side of the compressor and the four-way valve 2 and connected to the refrigerant piping between the outdoor heat exchanger 3 and the outdoor expansion valve 4. A bypass solenoid valve 6 is provided. When the outdoor heat exchanger 3 needs to be defrosted during heating operation, or when it becomes easy to form frost, the bypass solenoid valve 6 is opened and the high-temperature and high-pressure gas refrigerant discharged from the compressor is used. Part of the (high temperature refrigerant) flows into the bypass circuit 17, passes through the bypass solenoid valve 6, is branched into five distribution pipes 10 having capillary tubes 19, and is connected to the five branch pipes 21, respectively. It is configured to flow into each path of the outdoor heat exchanger 3. The capillary tube 19 is used to depressurize the high-temperature and high-pressure gas refrigerant and adjust the flow rate of gas flowing into each path of the outdoor heat exchanger 3 to an appropriate flow rate.

  The outdoor heat exchanger 3 uses a plate fin type heat exchanger configured by a large number of plate-like fins juxtaposed at a narrow interval and a meandering refrigerant pipe passing through these fins. Heat exchange is performed between the refrigerant flowing in the refrigerant pipe and the outside air (outdoor air) ventilated by the outdoor fan 23.

  The outdoor expansion valve 4 depressurizes the refrigerant flowing through the main circuit of the refrigeration cycle, is constituted by an electronic expansion valve, and is installed between the liquid blocking valve 12 and the distributor 20.

  The compressor 1 is composed of a variable capacity compressor whose operating frequency is controlled by an inverter. The four-way valve 2 is a valve for switching the flow direction of the refrigerant discharged from the compressor 1 and the flow direction of the refrigerant sucked into the compressor 1. The four-way valve 2 is changed to a solid line by the control device 16 during heating operation. The flow path shown is formed, and control is performed so as to form the flow path shown by the dotted line during the cooling operation.

  The control device 16 is mounted on the control board of the outdoor unit together with an outdoor operation switch and the like, and controls each device constituting the air conditioner 50.

  Reference numeral 24 denotes a thermistor (temperature detection means) for detecting the outdoor temperature, and is installed upstream of the outdoor heat exchanger 3. Reference numeral 25 denotes a thermistor (temperature detection means) that detects the temperature of the portion on the refrigerant inlet side of the outdoor heat exchanger 3 during heating, and is installed on the refrigerant pipe, plate-like fins, or the like.

Next, the basic operation of the refrigeration cycle of the air conditioner 50 will be described.
In the heating operation, as described above, the high-temperature and high-pressure gas refrigerant from the compressor 1 enters the indoor unit via the four-way valve 2, the gas blocking valve 11, and the gas connection pipe 53, as indicated by the solid line arrow, It is condensed to become a liquid refrigerant. This liquid refrigerant passes through the open indoor expansion valve 8, the liquid connection pipe 54, and the liquid blocking valve 12, and is decompressed by the outdoor expansion valve 4 to become a low-temperature and low-pressure gas-liquid mixed refrigerant. It evaporates in the outdoor heat exchanger 3 to become a gas refrigerant and returns to the compressor 1.

  During this heating operation, by opening the bypass solenoid valve 6 of the bypass circuit 17, a part of the gas refrigerant discharged from the compressor 1 branches off from the flow to the four-way valve 2, and the bypass solenoid valve After passing through 6, it is distributed and flows into the plurality of distribution pipes 10 having capillary tubes 19. The refrigerant that has passed through the distribution pipes 10 is then decompressed through the outdoor expansion valve 4 and is distributed to the plurality of branch pipes 21 by the distributor and merged with the main-stream side refrigerant flowing into the outdoor heat exchanger 3. It flows into the outdoor heat exchanger 3. Thereby, compared with the case where a part of the discharge gas refrigerant is not bypassed (when the bypass solenoid valve 6 is closed), the temperature of the outdoor heat exchanger 3 can be increased and frost formation can be prevented. If it is frosted, it can be defrosted.

  As in this embodiment, the refrigerant from the bypass circuit 17 is distributed to the plurality of distribution pipes 10 each having a capillary tube, so that the refrigerant can be uniformly distributed to each path of the outdoor heat exchanger 3. It is possible to prevent the entire outdoor heat exchanger 3 from being defrosted uniformly or conceived with a uniform temperature distribution.

During the cooling operation of the air conditioner, the gas refrigerant discharged from the compressor 1 flows to the outdoor heat exchanger 3 via the four-way valve 2 and is condensed by the outdoor heat exchanger 3 as indicated by a dotted arrow. It becomes a liquid refrigerant. This liquid refrigerant flows to the indoor unit through the fully expanded outdoor expansion valve 4, the liquid blocking valve 12, and the liquid connection pipe 54, and is decompressed by the indoor expansion valve of the indoor unit to become a low-pressure gas-liquid mixed refrigerant. The decompressed refrigerant is evaporated in the indoor heat exchanger of the indoor unit, converted into a gas refrigerant, and returned to the compressor 1.
During the cooling operation, the bypass solenoid valve 6 is always closed and the bypass circuit 17 is not used.

  The present embodiment includes a bypass circuit 17 connected between the outdoor heat exchanger 3 and the outdoor expansion valve 4 from the discharge side of the compressor 1, and this bypass circuit is connected to a plurality of distribution pipes 10 having capillary tubes 19. Since it is configured to distribute and flow to the outdoor heat exchanger 3, the bypass circuit 17 is opened when the temperature of the outdoor heat exchanger 3 decreases and the outdoor heat exchanger 3 may be frosted. As described above, the high-temperature and high-pressure refrigerant from the compressor 1 can be distributed and supplied to each path of the outdoor heat exchanger 3 through the plurality of distribution pipes 10. That is, in the present embodiment, each of the distribution pipes 10 is provided with a capillary tube 19, so that each path of the outdoor heat exchanger can be adjusted by adjusting the size of the capillary tube (the diameter and length of the capillary tube). It is possible to flow an optimum bypass flow rate. That is, in a heat exchanger having a plurality of paths, there are paths where the refrigerant easily flows or difficult to flow, and it is difficult to uniformly flow the refrigerant through each path. It is conceivable to change the refrigerant pipe size for each pass so that the refrigerant flows as uniformly as possible in each pass. However, the adjustment of the pipe size allows rough adjustment and allows the refrigerant to flow uniformly in each pass. That is still difficult. For this reason, it is difficult to avoid the formation of a path that easily forms frost or a path that hardly forms frost.

  In the present embodiment, each distribution pipe 10 of the bypass circuit 17 is provided with a capillary tube 19, and by adjusting the size of this capillary tube, the outdoor heat exchanger can be easily frosted or difficult to frost. On the other hand, the size of the capillary tube is adjusted according to the ease of frost formation. It is possible to flow an optimum bypass flow rate. Many sizes of capillary tubes are available on the market, and by adjusting the flow rate while reducing the pressure, the bypass flow rate to each path can be easily adjusted finely. Accordingly, the entire outdoor heat exchanger can be uniformly defrosted with a smaller or the minimum necessary bypass flow rate, or the temperature can be made uniform so as to avoid the frost formation (the temperature of the outdoor heat exchanger 3 is prevented from being lowered). Frost can be avoided).

  In addition, when the outdoor heat exchanger 3 is designed and manufactured, in a heat exchanger having a plurality of paths, a path through which the refrigerant easily flows or a path through which the refrigerant flows is determined. (Resistance). In the case of an outdoor heat exchanger manufactured with the same design, the flow rate for each path has the same tendency, so the size of the capillary tube 19 installed in each distribution pipe 10 of the bypass circuit 17 can be determined.

  Further, the ease of frost formation in the outdoor heat exchanger varies depending on the position of the path in addition to the flow rate for each path. That is, since the higher-humidity outside air flows into the upstream side (the air suction side) with respect to the air flow in the outdoor heat exchanger 3 and dehumidifies and the humidity decreases toward the downstream side, the path disposed on the upstream side Tends to form frost, and the path arranged on the downstream side has a tendency to hardly form frost. Therefore, the size of the capillary tube 19 may be selected so that a larger bypass flow rate flows in the upstream path and a smaller bypass flow rate in the downstream side.

Next, the defrosting operation control in the control device 16 of the embodiment shown in FIG. 1 will be described with reference to the flowchart shown in FIG.
First, the outdoor heat exchanger temperature is detected by the thermistor 25, and the outdoor air temperature is detected by the thermistor 24 (step S1). Next, in step S2, it is determined whether or not the outdoor heat exchanger 3 may be frosted based on the temperature detected in step S1. For example, if the outdoor temperature detected by the thermistor 24 is 5 ° C. or higher and the temperature of the outdoor heat exchanger 3 detected by the thermistor 25 is 0 ° C. or lower, it is determined that there is a risk of frost formation. .

  If it is determined that there is a risk of frost formation, the process proceeds to step S3. If the bypass solenoid valve 6 is not open, the bypass solenoid valve 6 is opened (step S4), and the high-temperature and high-pressure refrigerant on the compressor discharge side is opened. A part is introduced into the bypass circuit 17 and flows into the outdoor heat exchanger 3. Thereby, the temperature of the outdoor heat exchanger 3 is raised, and if it is frosted, it can be defrosted, and when there is a possibility of frost formation, frost formation can be avoided. After step S4, the process returns to step S1.

In step S1, the temperature of the outdoor heat exchanger and the outside air temperature are detected again by the thermistors 24 and 25. If it is determined in step S2 that there is still a possibility of frost formation, the process proceeds to step S3, and the bypass solenoid valve 6 is opened. Since it is in a state, the process returns to step S1.
If it is determined in step S2 that there is no risk of frost formation, the process proceeds to step S5. If the bypass solenoid valve 6 is closed, the process returns to step S1, and if the bypass solenoid valve 6 is open, the process proceeds to step S6. . In step S6, it is determined whether or not the outdoor heat exchanger 3 is at a temperature at which frost is not formed and there is no fear of frost formation. In this example, if the temperature of the outdoor heat exchanger 3 is 2 ° C. or higher, it is determined that there is no risk of frost formation, the bypass solenoid valve 6 is closed (step S7), and the high-temperature and high-pressure refrigerant is removed from the bypass circuit 17 outdoors. The introduction into the heat exchanger 3 is stopped, and the air conditioner 50 returns to normal operation.
Thereafter, the control device 16 is controlled to repeat the same operation.

A preferred specific example in this embodiment will be described as follows.
(1) At least one or more of the capillary tubes provided in each of the plurality of distribution pipes is configured to have a size different from that of other capillary tubes, thereby minimizing defrosting in each path of the outdoor heat exchanger. Appropriate amount of hot gas can be supplied.
(2) The size of the capillary tube of the distribution pipe connected to each path is determined according to the flow path resistance of each of the plurality of paths of the outdoor heat exchanger. The size of the capillary tube of the distribution pipe to be connected is increased so as to increase the inflowing bypass flow rate. That is, since a large amount of refrigerant flows through the path having a small flow path resistance, frost formation is likely to occur. Therefore, a larger amount of high-temperature gas is allowed to flow from the bypass circuit, thereby enabling uniform defrosting as a whole.
(3) The bypass flow rate flowing from the bypass flow path is relatively larger in the path disposed on the upstream side with respect to the air flow of the outdoor heat exchanger than in the path disposed on the downstream side. Next, the size of the capillary tube of the distribution pipe is determined.
(4) When it is determined that the outdoor heat exchanger is frosted or frosted, the bypass solenoid valve of the bypass circuit is opened, and one of the high-temperature refrigerant from the compressor discharge side is opened. A portion is branched and flows into the outdoor heat exchanger via the bypass circuit.
(5) temperature detection means for detecting the outdoor temperature and temperature detection means for detecting the temperature of the outdoor heat exchanger, and based on the temperatures detected by these temperature detection means The heat exchanger has a control device that determines whether or not there is a risk of frost formation.
(6) The temperature detection means for detecting the temperature of the outdoor heat exchanger is to detect the temperature of the portion of the outdoor heat exchanger that is on the refrigerant inlet side during heating.
(7) When the control device determines that the outdoor heat exchanger may be frosted, the control device performs control to open the bypass electromagnetic valve of the bypass circuit, and removes the refrigerant from the discharge side of the compressor. And supplying the outdoor heat exchanger via the bypass circuit.

  According to this embodiment described above, since the bypass circuit has a plurality of distribution pipes having capillary tubes, the amount of bypass to each path of the outdoor heat exchanger can be adjusted appropriately, and the outdoor heat exchanger The defrosting performance can be improved by uniformly melting the attached frost. Moreover, according to the present Example, the continuous heating operation is possible while performing the defrosting operation, and the air conditioner that can ensure the comfort of the indoor space is obtained. Furthermore, since the bypass amount of hot gas to each pass can be adjusted optimally with a capillary tube, the amount of bypass of hot gas can be minimized and the heating capacity is reduced even when the bypass solenoid valve is open. Can be suppressed.

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Four-way valve 3 ... Outdoor heat exchanger 4 ... Outdoor expansion valve 6 ... Bypass solenoid valve 10 ... Distribution pipe 11 ... Gas prevention valve 12 ... Liquid prevention valve 16 ... Controller 17 ... Bypass circuit 19 ... Capillary tube 20 ... distributor 21 ... branch pipe 22 ... header 23 ... outdoor fans 24, 25 ... thermistor (temperature detecting means)
50 ... Air conditioner 51 ... Outdoor unit 53 ... Gas connection pipe 54 ... Liquid connection pipe

Claims (9)

A compressor, an outdoor heat exchanger, an outdoor expansion valve, and at least an air conditioner capable of heating operation,
The outdoor heat exchanger is composed of a plurality of passes,
Providing a bypass circuit for connecting the discharge side of the compressor and the inlet side of the outdoor heat exchanger during heating operation;
The bypass circuit includes a bypass solenoid valve and a plurality of distribution pipes having capillary tubes on a side connected to the outdoor heat exchanger, and the plurality of distribution pipes are connected to a plurality of paths of the outdoor heat exchanger. Each connected ,
An air conditioner characterized in that at least one of the capillary tubes provided in each of the plurality of distribution pipes is different in size from other capillary tubes . In an air conditioner that configures a refrigeration cycle by connecting a compressor, a four-way valve, an indoor heat exchanger, an outdoor expansion valve, an outdoor heat exchanger with a refrigerant pipe,
The outdoor heat exchanger includes a plurality of paths, and the liquid refrigerant from the indoor heat exchanger passes through the outdoor expansion valve and then branches to a plurality of branch pipes to be used as the plurality of paths of the outdoor heat exchanger. It is configured to flow each,
Providing a bypass circuit for branching a part of the high-temperature refrigerant discharged from the compressor and flowing it to the inlet side during heating operation of the outdoor heat exchanger;
The bypass circuit is provided with a bypass solenoid valve, and the side connected to the outdoor heat exchanger is configured with a plurality of distribution pipes having capillary tubes, and the plurality of distribution pipes are connected to each path of the outdoor heat exchanger. each connected,
An air conditioner characterized in that at least one of the capillary tubes provided in each of the plurality of distribution pipes is different in size from other capillary tubes . An air conditioner configured by connecting an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve, and an indoor unit having an indoor heat exchanger and an indoor expansion valve with a gas connection pipe and a liquid connection pipe In the machine
The outdoor heat exchanger has a plurality of paths, and during heating operation, the refrigerant from the indoor unit passes through an outdoor expansion valve and then branches to a plurality of branch pipes, and the plurality of paths of the outdoor heat exchanger. To each flow in,
Providing a bypass circuit for partially branching the high-temperature refrigerant discharged from the compressor and flowing it to the inlet side during heating operation of the outdoor heat exchanger;
The bypass circuit includes a bypass solenoid valve, and the side connected to the outdoor heat exchanger is configured by a plurality of distribution pipes having capillary tubes, and is connected to each path of the outdoor heat exchanger ,
An air conditioner characterized in that at least one of the capillary tubes provided in each of the plurality of distribution pipes is different in size from other capillary tubes . In any one of Claims 1-3 , according to each flow path resistance of the several path | pass of an outdoor heat exchanger, the size of the capillary tube of the said distribution pipe connected to each said path | pass is determined, and flow path resistance An air conditioner characterized in that the smaller the path, the larger the size of the capillary tube of the distribution pipe connected thereto, and the larger the bypass flow rate that flows in . In any one of Claims 1-4, the bypass flow volume which flows in into the path | pass arrange | positioned upstream with respect to the air flow of the said outdoor heat exchanger from the said bypass flow path rather than the path | pass arrange | positioned downstream. The air conditioner is characterized in that the size of the capillary tube of the distribution pipe is determined so as to be relatively large . In any one of Claims 1-5, when it is judged that the said outdoor heat exchanger is frosting or there exists a possibility of frost formation, the bypass solenoid valve of the said bypass circuit is opened, and compressor discharge An air conditioner characterized in that a part of the high-temperature refrigerant from the side is branched and flows into the outdoor heat exchanger via the bypass circuit . A compressor, an outdoor heat exchanger, an outdoor expansion valve, and at least an air conditioner capable of heating operation,
The outdoor heat exchanger is composed of a plurality of passes,
Providing a bypass circuit for connecting the discharge side of the compressor and the inlet side of the outdoor heat exchanger during heating operation;
The bypass circuit includes a bypass solenoid valve and a plurality of distribution pipes having capillary tubes on a side connected to the outdoor heat exchanger, and the plurality of distribution pipes are connected to a plurality of paths of the outdoor heat exchanger. Each connected,
Furthermore, a temperature detection means for detecting the outdoor temperature and a temperature detection means for detecting the temperature of the outdoor heat exchanger are provided, and the outdoor heat is based on the temperature detected by these temperature detection means. An air conditioner comprising a control device that determines whether or not the exchanger has a risk of frost formation . 8. The air according to claim 7 , wherein the temperature detecting means for detecting the temperature of the outdoor heat exchanger detects a temperature of a portion of the outdoor heat exchanger that becomes a refrigerant inlet side during heating. Harmony machine. 9. The control device according to claim 7 , wherein when the control device determines that the outdoor heat exchanger may be frosted, the control device performs control to open a bypass solenoid valve of the bypass circuit, and discharges the compressor The air conditioner is characterized in that the refrigerant from is supplied to the outdoor heat exchanger via the bypass circuit .

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