JP2016090092A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner which does not interrupt a heating operation and which can shorten defrosting time.SOLUTION: When performing defrosting of a first outdoor heat exchanger 23a during a heating operation, a CPU switches so that a port a communicates with a port b of a four-way valve switching part, and a port c communicates with a port d. At this time, the CPU does not switch a second four-way valve 22b and a third four-way valve 25, and they are left to be the same as the heating operation. By switching only the first four-way valve 22a as stated before, the first outdoor heat exchanger 23a functions as a condenser, a second outdoor heat exchanger 23b functions as an evaporator, and indoor heat exchangers 51a-51c function as condensers. When the defrosting of the first outdoor heat exchanger 23a finishes, succeedingly, defrosting of the second outdoor heat exchanger 23b is performed by switching so that the first outdoor heat exchanger 23a functions as the evaporator and the second outdoor heat exchanger 23b functions as the condenser.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an air conditioner in which an outdoor unit and an indoor unit are connected to each other through a plurality of refrigerant pipes.

  Conventionally, an air conditioner in which an outdoor unit and an indoor unit are connected to each other by a plurality of refrigerant pipes has been proposed. When this air conditioner performs heating operation and the temperature of the outdoor heat exchanger becomes 0 ° C. or less, the outdoor heat exchanger may be frosted. When frost is formed on the outdoor heat exchanger, ventilation to the outdoor heat exchanger is hindered by frost, and heat exchange efficiency in the outdoor heat exchanger is reduced. Therefore, if frost formation occurs in the outdoor heat exchanger, it is necessary to perform a defrosting operation in order to remove the frost from the outdoor heat exchanger.

  In the defrosting operation, the outdoor heat exchanger functioning as an evaporator is switched to function as a condenser, that is, a high-temperature and high-pressure refrigerant discharged from the compressor by switching the refrigeration cycle from the heating cycle to the cooling cycle. There is a so-called reverse cycle defrosting operation in which frost is melted by flowing into the outdoor heat exchanger. However, when the reverse cycle defrosting operation is performed, the refrigeration cycle becomes a cooling cycle and the heating operation is interrupted, which may impair the comfort of the user.

  On the other hand, for example, as in the air conditioner described in Patent Document 1, the outdoor heat exchanger is divided into two, and the high-temperature and high-pressure refrigerant discharged from the compressor is left as the heating cycle while the refrigeration cycle remains as the heating cycle. There has also been proposed one that defrosts the outdoor heat exchanger by individually flowing into the exchanger.

  In the air conditioner described in Patent Document 1, the discharge side of the compressor and each refrigerant inlet side when each outdoor heat exchanger functions as an evaporator are connected by a hot gas bypass pipe provided with an open / close valve. Yes. If frost formation occurs in the outdoor heat exchanger during heating operation, only the open / close valve corresponding to one of the outdoor heat exchangers is opened to allow the refrigerant discharged from the compressor to flow into the outdoor heat exchanger. After the defrosting of the outdoor heat exchanger, only the open / close valve corresponding to the other outdoor heat exchanger is opened and the refrigerant discharged from the compressor is allowed to flow into the outdoor heat exchanger. Do frost. Thereby, even when one of the outdoor heat exchangers is defrosted, the other outdoor heat exchanger continues to function as an evaporator, so that the outdoor heat exchanger can be defrosted without interrupting the heating operation. .

JP 2008-64381 A

  However, in an air conditioner that performs defrosting by individually flowing high-temperature and high-pressure refrigerant into the above-described two-part outdoor heat exchanger, the refrigeration cycle remains in the heating cycle and the refrigerant is sequentially compressed to the refrigerant inflow side of the outdoor heat exchanger. The refrigerant discharged from the machine is introduced to perform defrosting. The frost of the outdoor heat exchanger that performs defrosting is melted and the liquid refrigerant or gas-liquid two-phase refrigerant flowing out of the outdoor heat exchanger is compressed without passing through the evaporator, that is, without absorbing heat from the outside air in the evaporator. Inhaled into the machine. Thereby, when one outdoor heat exchanger was defrosting, there existed a problem that the discharge temperature of a compressor fell and it took time for the defrost of the other outdoor heat exchanger.

  The present invention solves the above-described problems, and an object thereof is to provide an air conditioner that can shorten the defrosting time without interrupting the heating operation.

  In order to solve the above-described problems, an air conditioner of the present invention includes a refrigerant circuit in which an outdoor unit and an indoor unit are connected by a liquid pipe and a gas pipe, and a control unit. And a plurality of outdoor heat exchanger units, a high pressure gas pipe, a low pressure gas pipe, an outdoor unit gas pipe, an outdoor unit liquid pipe, and a second flow path switching means, and a refrigerant discharge side of the compressor and a second flow path switching. The means is connected by a high pressure gas pipe, the refrigerant suction side of the compressor and the second flow path switching means are connected by a low pressure gas pipe, the gas pipe and the second flow path switching means are connected by an outdoor unit gas pipe, and the liquid pipe And outdoor unit liquid pipe are connected. The outdoor heat exchanger unit has an outdoor heat exchanger, a first flow path switching means, a high pressure distribution pipe, a low pressure distribution pipe, a liquid distribution pipe, and a connection pipe, and one refrigerant inlet / outlet and the first flow path of the outdoor heat exchanger. The switching means is connected by a connection pipe, the other refrigerant inlet / outlet of the outdoor heat exchanger and the outdoor unit liquid pipe are connected by a liquid distribution pipe, the high pressure gas pipe and the first flow path switching means are connected by a high pressure distribution pipe, and the low pressure gas pipe And the first flow path switching means are connected by a low-pressure branch pipe. The control means switches the first flow path switching means of each outdoor heat exchanger unit so that the outdoor heat exchanger of each outdoor heat exchanger unit functions as an evaporator, and performs high-pressure gas when performing the heating operation. When the second flow path switching means is switched so that the pipe and the outdoor unit gas pipe are connected and the defrosting operation is performed during the heating operation, the first flow path switching means is switched so that the outdoor heat exchanger functions as a condenser. The outdoor heat exchanger is defrosted sequentially for each outdoor heat exchanger unit, and the second flow path switching unit and the outdoor heat exchanger unit not performing defrosting maintain the state during heating operation. It is.

  According to the air conditioner of the present invention configured as described above, when performing defrosting of a plurality of outdoor heat exchangers during heating operation, other outdoor heat is defrosted while defrosting some of the outdoor heat exchangers. Since the heating operation is performed by the exchanger, the outdoor heat exchanger can be defrosted without interrupting the heating operation. Further, since the refrigerant flowing out from the outdoor heat exchanger to be defrosted is evaporated by the outdoor heat exchanger for heating and sucked into the compressor, the discharge temperature of the compressor is not lowered and the defrosting time can be shortened.

It is a refrigerant circuit figure when the air conditioning apparatus in embodiment of this invention performs heating operation. It is a refrigerant circuit figure when the air conditioning apparatus in embodiment of this invention performs air_conditionaing | cooling operation. It is a block diagram explaining the structure of the outdoor unit control part in embodiment of this invention. It is a fan rotation speed table at the time of starting in embodiment of this invention. It is a refrigerant circuit figure when defrosting the 1st outdoor heat exchanger.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, an air conditioning apparatus will be described as an example in which three indoor units are connected in parallel to one outdoor unit, and cooling operation or heating operation can be performed simultaneously in all indoor units. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention.

  The structure of the air conditioning apparatus in this embodiment is demonstrated using FIG. As shown in FIG. 1, an air conditioner 1 according to the present embodiment is installed indoors with one outdoor unit 2 and is connected indoors in parallel with a liquid pipe 8 and a gas pipe 9. The three indoor units 5a to 5c are provided. Specifically, the liquid pipe 8 has one end connected to the closing valve 26 of the outdoor unit 2 and the other end branched to be connected to the liquid pipe connecting portions 53a to 53c of the indoor units 5a to 5c. The gas pipe 9 has one end connected to the closing valve 27 of the outdoor unit 2 and the other end branched to be connected to the gas pipe connecting portions 54a to 54c of the indoor units 5a to 5c. The refrigerant circuit 100 of the air conditioner 1 is configured as described above.

  First, the outdoor unit 2 will be described. The outdoor unit 2 includes a compressor 21, a first four-way valve 22a and a second four-way valve 22b, which are first flow path switching means, a first outdoor heat exchanger 23a, a second outdoor heat exchanger 23b, The one outdoor expansion valve 24a, the second outdoor expansion valve 24b, the third four-way valve 25 as the second flow path switching means, the closing valve 26 to which one end of the liquid pipe 8 is connected, and one end of the gas pipe 9 are A connected shut-off valve 27 and an outdoor fan 28 are provided. And these each apparatus except the outdoor fan 28 is mutually connected by each refrigerant | coolant piping explained in full detail below, and the outdoor unit refrigerant circuit 20 which makes a part of the refrigerant circuit 100 is comprised.

  The compressor 21 is a variable capacity compressor that can vary its operating capacity by being driven by a motor (not shown) whose rotation speed is controlled by an inverter. One end of the high-pressure gas pipe 41 is connected to the refrigerant discharge side of the compressor 21, and the other end of the high-pressure gas pipe 41 is connected to the port p of the third four-way valve 25. One end of the first high-pressure branch pipe 41a and one end of the second high-pressure branch pipe 41b are connected to the connection point A of the high-pressure gas pipe 41, respectively. The other end of the first high-pressure branch pipe 41a is connected to the port a of the first four-way valve 22a. The other end of the second high-pressure branch pipe 41b is connected to a port e of a second four-way valve 22b described later.

  One end of the low-pressure gas pipe 42 is connected to the refrigerant suction side of the compressor 21, and the other end of the low-pressure gas pipe 42 is connected to the port r of the third four-way valve 25. One end of the first low-pressure distribution pipe 42a is connected to the connection point C of the low-pressure gas distribution pipe 42, and the other end of the first low-pressure distribution pipe 42a is connected to the port c of the first four-way valve 22a. Further, one end of the second low-pressure distribution pipe 42b is connected to the connection point D of the low-pressure gas distribution pipe 42, and the other end of the second low-pressure distribution pipe 42b is connected to the port g of the second four-way valve 22b.

  The first four-way valve 22a is a valve for switching the flow direction of the refrigerant in the first outdoor heat exchanger 23a, and includes four ports a, b, c, and d. As described above, the first high-pressure branch pipe 41a is connected to the port a. The port b is connected to one refrigerant inlet / outlet of the first outdoor heat exchanger 23a by the first connection pipe 43a. As described above, the first low-pressure branch pipe 42a is connected to the port c. One end of a first bypass pipe 45a having a first capillary tube 37a is connected to the port d, and the other end of the first bypass pipe 45a is connected to the first low-pressure branch pipe 42a at a connection point E. .

  The second four-way valve 22b is a valve for switching the flow direction of the refrigerant in the second outdoor heat exchanger 23b, and includes four ports e, f, g, and h. As described above, the second high-pressure branch pipe 41b is connected to the port e. The port f is connected to one refrigerant inlet / outlet of the second outdoor heat exchanger 23b through the second connection pipe 43b. As described above, the second low-pressure branch pipe 42b is connected to the port g. One end of a second bypass pipe 45b having a second capillary tube 37b is connected to the port h, and the other end of the second bypass pipe 45b is connected to the second low-pressure branch pipe 42b at a connection point F. .

  The first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b exchange heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28 described later. As described above, one refrigerant inlet / outlet of the first outdoor heat exchanger 23a is connected to the port b of the first four-way valve 22a by the first connection pipe 43a, and one end of the first liquid distribution pipe 44a is connected to the other refrigerant inlet / outlet. It is connected. Also, as described above, one refrigerant inlet / outlet of the second outdoor heat exchanger 23b is connected to the port f of the second four-way valve 22b by the second connection pipe 43b, and the other refrigerant inlet / outlet is connected to the second liquid distribution pipe 44b. One end is connected. The other end of the first liquid distribution pipe 44a and the other end of the second liquid distribution pipe 44b are each connected to one end of the outdoor unit liquid pipe 44 at a connection point B, and the other end of the outdoor unit liquid pipe 44 is connected to the closing valve 26. Has been.

  The first outdoor heat exchanger 23a, the first four-way valve 22a, the first high-pressure distribution pipe 41a, the first low-pressure distribution pipe 42a, the first connection pipe 43a, and the first liquid distribution pipe 44a The heat exchanger unit 20a is configured, the second outdoor heat exchanger 23b, the second four-way valve 22b, the second high-pressure distribution pipe 41b, the second low-pressure distribution pipe 42b, the second connection pipe 43b, and the second liquid distribution pipe. 44b constitutes a second outdoor heat exchanger unit 20b. The first outdoor heat exchanger unit 20a and the second outdoor heat exchanger unit 20b are the outdoor heat exchanger units of the present invention.

  Each of the first outdoor expansion valve 24a and the second outdoor expansion valve 24b is an electronic expansion valve. The first outdoor expansion valve 24a is provided in the first liquid distribution pipe 44a, and the amount of refrigerant flowing into the first outdoor heat exchanger 23a or the first outdoor heat exchanger is adjusted by adjusting the opening degree thereof. The amount of refrigerant flowing out of 23a is adjusted. The second outdoor expansion valve 24b is provided in the second liquid distribution pipe 44b, and the amount of refrigerant flowing into the second outdoor heat exchanger 23b or the second outdoor heat exchanger is adjusted by adjusting the opening degree thereof. The amount of refrigerant flowing out of 23b is adjusted.

  The third four-way valve 25 is a valve for connecting the high pressure gas pipe 41 and the gas pipe 9 via the outdoor unit gas pipe 47 and the closing valve 27 or connecting the low pressure gas pipe 42 and the gas pipe 9. , P, q, r, and s. As described above, the high-pressure gas pipe 41 is connected to the port p. The port q is connected to the closing valve 27 by an outdoor unit gas pipe 47. As described above, the low-pressure gas pipe 42 is connected to the port r. One end of a third bypass pipe 46 having a third capillary tube 38 is connected to the port s, and the other end of the third bypass pipe 46 is connected to the low-pressure gas pipe 42 at a connection point G.

  The outdoor fan 28 is formed of a resin material, and is disposed in the vicinity of the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b. The outdoor fan 28 is rotated by a fan motor (not shown) to take outside air into the outdoor unit 2 from a suction port (not shown), and exchanges heat with the refrigerant in the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b. Outside air is discharged to the outside of the outdoor unit 2 from a blower outlet (not shown).

  In addition to the configuration described above, the outdoor unit 2 is provided with various sensors. As shown in FIG. 1, in the vicinity of the discharge side of the compressor 21 in the high-pressure gas pipe 41, a discharge pressure sensor 31 that detects the pressure of the refrigerant discharged from the compressor 21, and the refrigerant discharged from the compressor 21 A discharge temperature sensor 33 for detecting the temperature is provided. Near the suction side of the compressor 21 in the low-pressure gas pipe 42, a suction pressure sensor 32 that detects the pressure of the refrigerant sucked into the compressor 21 and a suction temperature sensor that detects the temperature of the refrigerant sucked into the compressor 21. 34 is provided.

  Between the first outdoor heat exchanger 23a and the first outdoor expansion valve 44a in the first liquid distribution pipe 44a, the refrigerant flows into the first outdoor heat exchanger 23a or flows out from the first outdoor heat exchanger 23a. The 1st heat exchange temperature sensor 35a which detects the temperature of this is provided. A refrigerant that flows into or out of the second outdoor heat exchanger 23b between the second outdoor heat exchanger 23b and the second outdoor expansion valve 44b in the second liquid distribution pipe 44b. A second heat exchanger temperature sensor 35b is provided for detecting the temperature of the first heat exchanger. An outdoor air temperature sensor 36 that detects the temperature of the outside air flowing into the outdoor unit 2, that is, the outside air temperature, is provided in the vicinity of a suction port (not shown) of the outdoor unit 2.

  The outdoor unit 2 is provided with an outdoor unit control means 200. The outdoor unit control means 200 is mounted on a control board stored in an electrical component box (not shown) of the outdoor unit 2. As shown in FIG. 3, the outdoor unit control means 200 includes a CPU 210, a storage unit 220, a communication unit 230, a sensor input unit 240, an inverter unit 250, and a four-way valve switching unit 260.

  The storage unit 220 includes a ROM and a RAM, and stores a control program for the outdoor unit 2, detection values corresponding to detection signals from various sensors, control states of the compressor 21 and the outdoor fan 28, and the like. The communication unit 230 is an interface for performing communication with the indoor units 5a to 5c. The sensor input unit 240 captures detection results from various sensors of the outdoor unit 2 and outputs them to the CPU 210. The inverter unit 250 performs rotation control of the compressor 21. The four-way valve switching unit 260 switches each four-way valve by turning on and off the pilot solenoid valve (not shown) provided in each of the first four-way valve 22a, the second four-way valve 22b, and the third four-way valve 25. I do.

  CPU210 takes in the detection result in each sensor of outdoor unit 2 mentioned above via sensor input part 240. FIG. In addition, the CPU 210 takes in control signals transmitted from the indoor units 5 a to 5 c via the communication unit 230. The CPU 210 controls the drive of the compressor 21 through the inverter unit 250 based on the detection results and control signals taken in, and the first four-way valve 22a, the second four-way valve 22b, and the second through the four-way valve switching unit 260. 3 The four-way valve 25 is switched. Further, the CPU 210 controls the opening degree of the first outdoor expansion valve 24a and the second outdoor expansion valve 24b and the drive control of the outdoor fan 28 based on the acquired detection result and control signal.

  Next, the three indoor units 5a to 5c will be described. The three indoor units 5a to 5c are respectively branched into indoor heat exchangers 51a to 51c, indoor expansion valves 52a to 52c, and liquid pipe connection portions 53a to 53c to which the other ends of the branched liquid pipes 8 are connected. The gas pipe connecting portions 54a to 54c to which the other ends of the gas pipes 9 are connected are provided, and indoor fans 55a to 55c are provided. And these each apparatus except indoor fan 55a-55c is mutually connected by each refrigerant | coolant piping explained in full detail below, and comprises the indoor unit refrigerant circuit 50a-50c which makes a part of refrigerant circuit 100. FIG.

  In addition, since the structure of all the indoor units 5a-5c is the same, in the following description, only the structure of the indoor unit 5a is demonstrated and description is abbreviate | omitted about the other indoor units 5b and 5c. Moreover, in FIG. 1, what changed the end of the number provided to the component apparatus of the indoor unit 5a from a to b and c becomes the component apparatus of the indoor units 5b and 5c corresponding to the component apparatus of the outdoor unit 5a. .

  The indoor heat exchanger 51a exchanges heat between the refrigerant and room air taken into the interior of the indoor unit 5a through a suction port (not shown) by rotation of an indoor fan 55a, which will be described later. The indoor unit liquid pipe 71a is connected to the section 53a, and the other refrigerant inlet / outlet is connected to the gas pipe connecting section 54a through the indoor unit gas pipe 72a. Refrigerant pipes are connected to the liquid pipe connection portion 53a and the gas pipe connection portion 54a by welding, flare nuts, or the like. The indoor heat exchanger 51a functions as an evaporator when the indoor unit 5a performs a cooling operation, and functions as a condenser when the indoor unit 5a performs a heating operation.

  The indoor expansion valve 52a is provided in the indoor unit liquid pipe 71a. The indoor expansion valve 52a is an electronic expansion valve, and the amount of refrigerant flowing through the indoor heat exchanger 51a can be adjusted by adjusting the opening degree thereof. When the indoor heat exchanger 51a functions as an evaporator, the indoor expansion valve 52a is adjusted according to the required cooling capacity, and when the indoor heat exchanger 51a functions as a condenser, The opening is adjusted according to the required heating capacity.

  The indoor fan 55a is formed of a resin material and is disposed in the vicinity of the indoor heat exchanger 51a. The indoor fan 55a is rotated by a fan motor (not shown) to take indoor air into the indoor unit 5a from a suction port (not shown), and the indoor air exchanged with the refrigerant in the indoor heat exchanger 51a from the blower outlet (not shown) to the room. To supply.

  In addition to the configuration described above, the indoor unit 5a is provided with various sensors. Between the indoor heat exchanger 51a and the indoor expansion valve 52a in the indoor unit liquid pipe 71a, a liquid side temperature sensor 61a that detects the temperature of the refrigerant flowing into or out of the indoor heat exchanger 51a. Is provided. The indoor unit gas pipe 72a is provided with a gas side temperature sensor 62a that detects the temperature of the refrigerant flowing out of the indoor heat exchanger 51a or flowing into the indoor heat exchanger 51a. An indoor temperature sensor 63a that detects the temperature of the indoor air flowing into the indoor unit 5a, that is, the indoor temperature, is provided in the vicinity of a suction port (not shown) of the indoor unit 5a.

  Although illustration is omitted, indoor unit control means is mounted on the control board stored in the electrical component box of the indoor unit 5a. The detected values detected by the liquid side temperature sensor 61a, the gas side temperature sensor 62a, and the room temperature sensor 63a are input to the indoor unit control means, and the operating conditions (settings) set by the user by operating a remote controller (not shown) A signal including temperature and air volume is input. The indoor unit control means controls the opening degree of the indoor expansion valve 52a and the drive control of the indoor fan 55a based on the inputted various information and a control signal transmitted from the outdoor unit control means 200 described later.

  Next, the flow of the refrigerant and the operation of each part in the refrigerant circuit 100 during operation of the air-conditioning apparatus 1 in the present embodiment will be described with reference to FIGS. 1 to 5. The air conditioner 1 according to the present embodiment includes a heating operation for heating the room in which the indoor units 5a to 5c are installed, a cooling operation for cooling the room in which the indoor units 5a to 5c are installed, and the heating operation described above. When performing the defrosting operation, the frost adhered to the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b can be melted.

  In the following description, first, the operation of the air conditioner 1 during the heating operation will be described using FIG. 1, and then the operation of the air conditioner 1 during the cooling operation will be described using FIG. 2. Finally, operation | movement of the air conditioning apparatus 1 at the time of a defrost operation is demonstrated using FIG. 4 and FIG. In each of the drawings excluding FIG. 3, the arrows indicate the flow direction of the refrigerant in the refrigerant circuit 100, the heat exchanger that functions as a condenser is hatched, and the heat exchanger that functions as an evaporator is outlined. It is shown.

<Heating operation>
As shown in FIG. 1, when heating operation is performed, the CPU 210 of the outdoor unit control means 200 is in a state where the first four-way valve 22a is indicated by a solid line via the four-way valve switching unit 260, that is, the port a and the port d are It switches so that it may communicate and port b and port c communicate. In addition, the CPU 210 is in a state where the second four-way valve 22b is indicated by a solid line via the four-way valve switching unit 260, that is, the port e and the port h communicate with each other, and the port f and the port g communicate with each other. Switch to. Furthermore, the CPU 210 is in a state where the third four-way valve 25 is indicated by a solid line via the four-way valve switching unit 260, that is, the port p and the port q communicate with each other, and the port r and the port s communicate with each other. Thus, the high pressure gas pipe 41 and the gas pipe 9 are connected via the outdoor unit gas pipe 47 and the shut-off valve 27. By switching each four-way valve as described above, the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b function as evaporators, and the indoor heat exchangers 51a to 51c function as condensers.

  When the refrigerant circuit 100 is in the state shown in FIG. 1, the refrigerant discharged from the compressor 21 flows through the high-pressure gas pipe 41 and passes through the third four-way valve 25, the outdoor unit gas pipe 47, and the closing valve 27. It flows into the tube 9. The refrigerant flowing through the high pressure gas pipe 41 is also divided into the first high pressure branch pipe 41a and the second high pressure branch pipe 41b at the connection point A, but the refrigerant flowing into the first high pressure branch pipe 41a is the first four-way valve 22a, When flowing from the connection point E to the first low-pressure distribution pipe 42a through the first bypass pipe 45a, the flow rate is largely limited by the first capillary tube 37a provided in the first bypass pipe 45a. The refrigerant flowing into the second high-pressure distribution pipe 41b is provided in the second bypass pipe 45b when flowing from the connection point F to the second low-pressure distribution pipe 42b via the second four-way valve 22b and the second bypass pipe 45b. The flow rate is greatly limited by the second capillary tube 37b.

  The refrigerant flowing into the gas pipe 9 is divided and flows into the indoor units 5a to 5c via the gas pipe connecting portions 54a to 54c. The refrigerant flowing into the indoor units 5a to 5c flows through the indoor unit gas pipes 72a to 72c, flows into the indoor heat exchangers 51a to 51c, and is taken into the indoor units 5a to 5c by the rotation of the indoor fans 55a to 55c. Heat exchanges with the room air and condenses. As described above, the indoor heat exchangers 51a to 51c function as condensers, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchangers 51a to 51c is blown into the room from a blowout port (not shown), thereby The room where the machines 5a to 5c are installed is heated.

  The refrigerant flowing out of the indoor heat exchangers 51a to 51c flows through the indoor unit liquid pipes 71a to 71c, passes through the indoor expansion valves 52a to 52c, and is decompressed. The decompressed refrigerant flows into the liquid pipe 8 through the liquid pipe connecting portions 53a to 53c. The refrigerant flowing through the liquid pipe 8 and flowing into the outdoor unit 2 through the shut-off valve 26 flows through the outdoor unit liquid pipe 44 and is divided at the connection point B into the first liquid distribution pipe 44a and the second liquid distribution pipe 44b.

  The refrigerant flowing into the first liquid distribution pipe 44a is further decompressed when passing through the first outdoor expansion valve 24a. The refrigerant flowing into the first outdoor heat exchanger 23a from the first outdoor expansion valve 24a evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28. The refrigerant that has flowed out of the first outdoor heat exchanger 23a flows through the first connection pipe 43a, the first four-way valve 22a, and the first low-pressure distribution pipe 42a, and flows into the low-pressure gas pipe 42 from the connection point C.

On the other hand, the refrigerant flowing into the second liquid distribution pipe 44b is further depressurized when passing through the second outdoor expansion valve 24b. The refrigerant flowing into the second outdoor heat exchanger 23b from the second outdoor expansion valve 24b evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28. The refrigerant that has flowed out of the second outdoor heat exchanger 23b flows through the second connection pipe 43b, the second four-way valve 22b, and the second low-pressure distribution pipe 42b, and flows into the low-pressure gas pipe 42 from the connection point D.
The refrigerant that has flowed into the low pressure gas pipe 42 from the first low pressure branch pipe 42a and the second low pressure branch pipe 42b is sucked into the compressor 21 and compressed again.

<Cooling operation>
As shown in FIG. 2, when performing the cooling operation, the CPU 210 is configured so that the first four-way valve 22a is indicated by a solid line via the four-way valve switching unit 260, that is, the port a and the port b communicate with each other. The port c and the port d are switched so as to communicate with each other. In addition, the CPU 210 is in a state where the second four-way valve 22b is indicated by a solid line via the four-way valve switching unit 260, that is, the port e and the port f communicate with each other, and the port g and the port h communicate with each other. Switch to. Furthermore, the CPU 210 is in a state in which the third four-way valve 25 is indicated by a solid line via the four-way valve switching unit 260, that is, the port p and the port s communicate with each other, and the port q and the port r communicate with each other. The low-pressure gas pipe 42 and the gas pipe 9 are connected via the outdoor unit gas pipe 47 and the shut-off valve 27. By switching each four-way valve as described above, the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b function as condensers, and the indoor heat exchangers 51a to 51c function as evaporators.

  When the refrigerant circuit 100 is in the state shown in FIG. 2, the refrigerant discharged from the compressor 21 flows through the high-pressure gas pipe 41 and is divided into the first high-pressure branch pipe 41a and the second high-pressure branch pipe 41b at the connection point A. . A part of the refrigerant flowing through the high-pressure gas pipe 41 is provided in the third bypass pipe 46 when flowing from the connection point G to the low-pressure gas pipe 42 via the third four-way valve 25 and the third bypass pipe 46. The flow rate is largely limited by the third capillary tube 38.

  The refrigerant flowing through the first high-pressure branch pipe 41a flows into the first four-way valve 22a, flows from the first four-way valve 22a through the first connection pipe 43a, and flows into the first outdoor heat exchanger 23a. The refrigerant flowing into the first outdoor heat exchanger 23 a is condensed by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28. The refrigerant flowing out of the first outdoor heat exchanger 23a flows through the first liquid distribution pipe 44a, and flows into the outdoor unit liquid pipe 44 from the connection point B through the fully opened first outdoor expansion valve 24a.

On the other hand, the refrigerant flowing through the second discharge branch pipe 41b flows into the second four-way valve 22b, flows from the second four-way valve 22b through the second connection pipe 43b, and flows into the second outdoor heat exchanger 23b. The refrigerant flowing into the second outdoor heat exchanger 23 b is condensed by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28. The refrigerant flowing out of the second outdoor heat exchanger 23b flows through the second liquid distribution pipe 44b and flows into the outdoor unit liquid pipe 44 from the connection point B through the fully opened second outdoor expansion valve 24b.
The refrigerant that has flowed into the outdoor unit liquid pipe 44 from the first liquid distribution pipe 44 a and the second liquid distribution pipe 44 b flows into the liquid pipe 8 through the closing valve 26.

  When the refrigerant flowing through the liquid pipe 8 is divided and flows into the indoor units 5a to 5c via the liquid pipe connecting portions 53a to 53c, the refrigerant flows through the indoor unit liquid pipes 71a to 71c and passes through the indoor expansion valves 52a to 52c. The pressure is reduced to The refrigerant flowing into the indoor heat exchangers 51a to 51c from the indoor unit liquid tubes 71a to 71c evaporates by exchanging heat with the indoor air taken into the indoor units 5a to 5c by the rotation of the indoor fans 55a to 55c. . In this way, the indoor heat exchangers 51a to 51c function as evaporators, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchangers 51a to 51c is blown into the room from a blower outlet (not shown), thereby The room where the machines 5a to 5c are installed is cooled.

  The refrigerant that has flowed out of the indoor heat exchangers 51a to 51c flows through the indoor unit gas pipes 72a to 72c and flows into the gas pipe 9 through the gas pipe connection portions 54a to 54c. The refrigerant that flows through the gas pipe 9 and flows into the outdoor unit 2 through the closing valve 27 flows into the low-pressure gas pipe 42 through the outdoor unit gas pipe 47 and the third four-way valve 25, and flows through the low-pressure gas pipe 42 to be compressed. It is sucked into the machine 21 and compressed again.

<Defrosting operation>
When the air conditioner 1 performs the heating operation described above, for example, the refrigerant temperature detected by the first heat exchange temperature sensor 35a or the second heat exchange temperature sensor 35b, that is, the first heat exchange temperature sensor 35a or the second heat exchange temperature sensor 35b. The state in which the temperature of the alternating temperature sensor 35b is 0 ° C. or lower and the temperature of the first heat exchanger temperature sensor 35a or the second heat exchanger temperature sensor 35b is 10 ° C. or higher lower than the outdoor air temperature detected by the outdoor air temperature sensor 36 is 10 minutes or longer If it continues or if more than 3 hours have passed since the last defrosting operation, the first outdoor heat exchanger 23a or the second outdoor heat exchanger 23b has an amount that will affect the heating capacity. There may be frost.

  In the air conditioning apparatus 1 of the present embodiment, when frost is generated in the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b, the indoor units 5a to 5c are kept in the heating operation while continuing the heating operation. A defrosting operation for performing defrosting in the order of the heat exchanger 23a and the second outdoor heat exchanger 23b is executed. Hereinafter, the defrosting operation of the air conditioner 1 will be described in detail. First, the operation of the air conditioner 1 when the first outdoor heat exchanger 23a is defrosted will be described with reference to FIG. The operation of the air conditioning apparatus 1 when the second outdoor heat exchanger 23b is defrosted using 5 will be described.

<Defrosting of the first outdoor heat exchanger 23a>
As shown in FIG. 4, when the first outdoor heat exchanger 23a is defrosted during the heating operation, the CPU 210 indicates a state in which the first four-way valve 22a is indicated by a solid line via the four-way valve switching unit 260, that is, the port Switching is performed so that a and port b communicate with each other, and port c and port d communicate with each other. At this time, the CPU 210 does not switch the second four-way valve 22b and the third four-way valve 25 and keeps the heating operation. By switching only the first four-way valve 22a as described above, the first outdoor heat exchanger 23a functions as a condenser, the second outdoor heat exchanger 23b functions as an evaporator, and the indoor heat exchangers 51a to 51c Functions as a condenser.

  When the refrigerant circuit 100 is in the state shown in FIG. 4, the refrigerant discharged from the compressor 21 flows through the high-pressure gas pipe 41 and passes through the third four-way valve 25, the outdoor unit gas pipe 47, and the closing valve 27. It flows into the tube 9. The refrigerant flowing into the gas pipe 9 is divided and flows into the indoor units 5a to 5c via the gas pipe connecting portions 54a to 54c. Thereafter, the flow of the refrigerant until it flows into the outdoor unit 2 is the same as that in the heating operation described above, and thus the description thereof is omitted.

  The refrigerant flowing through the liquid pipe 8 and flowing into the outdoor unit 2 through the closing valve 26 flows through the outdoor unit liquid pipe 44 and flows from the connection point B to the second liquid distribution pipe 44b. The refrigerant flowing into the second liquid distribution pipe 44b is further depressurized when passing through the second outdoor expansion valve 24b. The refrigerant flowing into the second outdoor heat exchanger 23b from the second outdoor expansion valve 24b evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28. The refrigerant that has flowed out of the second outdoor heat exchanger 23b flows through the second connection pipe 43b, the second four-way valve 22b, and the second low-pressure distribution pipe 42b, and flows into the low-pressure gas pipe 42 from the connection point D. Then, the refrigerant flowing into the low pressure gas pipe 42 is sucked into the compressor 21 and compressed again.

On the other hand, the refrigerant that has flowed from the high-pressure gas pipe 41 into the first high-pressure branch pipe 41a at the connection point A flows from the first four-way valve 22a through the first connection pipe 43a and into the first outdoor heat exchanger 23a. The refrigerant that has flowed into the first outdoor heat exchanger 23a melts frost adhering to the first outdoor heat exchanger 23a to become a liquid refrigerant or a gas-liquid two-phase refrigerant. Thus, the refrigerant that has flowed into the first outdoor heat exchanger 23a functioning as a condenser melts frost, and the first outdoor heat exchanger 23a is defrosted.
The refrigerant flowing out of the first outdoor heat exchanger 23a flows through the first liquid distribution pipe 44a, is decompressed by the first outdoor expansion valve 24a, flows into the outdoor unit 2 from the indoor units 5a to 5c, and flows through the outdoor unit liquid pipe 44. The refrigerant joins at the connection point B.

  When the CPU 210 performs defrosting of the first outdoor heat exchanger 23a, if the refrigerant temperature detected by the first heat exchange temperature sensor 35a is 10 ° C. or higher, or the first outdoor heat exchanger 23a. If a predetermined time (for example, 5 minutes) has elapsed since the start of the defrosting, it is determined that the defrosting of the first outdoor heat exchanger 23a has been completed, and then the second outdoor heat exchanger 23b Perform defrosting.

<Defrosting of the second outdoor heat exchanger 23b>
As shown in FIG. 5, when the second outdoor heat exchanger 23 b is defrosted after the defrosting of the first outdoor heat exchanger 23 a, the CPU 210 switches the first four-way valve 22 a via the four-way valve switching unit 260. The state shown by the solid line, that is, switching is performed so that the port a and the port d communicate with each other and the port b and the port c communicate with each other. In addition, the CPU 210 is in a state where the second four-way valve 22b is indicated by a solid line via the four-way valve switching unit 260, that is, the port e and the port f communicate with each other, and the port g and the port h communicate with each other. Switch to. At this time, the CPU 210 does not switch the third four-way valve 25 and keeps the heating operation. By switching the first four-way valve 22a and the second four-way valve 22b as described above, the first outdoor heat exchanger 23a functions as an evaporator, the second outdoor heat exchanger 23b functions as a condenser, The exchangers 51a to 51c function as a condenser.

  When the refrigerant circuit 100 is in the state shown in FIG. 5, the refrigerant discharged from the compressor 21 flows through the high-pressure gas pipe 41 and passes through the third four-way valve 25, the outdoor unit gas pipe 47, and the closing valve 27. It flows into the tube 9. The refrigerant flowing into the gas pipe 9 is divided and flows into the indoor units 5a to 5c via the gas pipe connecting portions 54a to 54c. Thereafter, the flow of the refrigerant until it flows into the outdoor unit 2 is the same as that in the heating operation described above, and thus the description thereof is omitted.

  The refrigerant flowing through the liquid pipe 8 and flowing into the outdoor unit 2 through the shut-off valve 26 flows through the outdoor unit liquid pipe 44 and flows from the connection point B to the first liquid distribution pipe 44a. The refrigerant flowing into the first liquid distribution pipe 44a is further decompressed when passing through the first outdoor expansion valve 24a. The refrigerant flowing into the first outdoor heat exchanger 23a from the first outdoor expansion valve 24a evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 28. The refrigerant that has flowed out of the first outdoor heat exchanger 23a flows through the first connection pipe 43a, the first four-way valve 22a, and the first low-pressure distribution pipe 42a, and flows into the low-pressure gas pipe 42 from the connection point C. Then, the refrigerant flowing into the low pressure gas pipe 42 is sucked into the compressor 21 and compressed again.

On the other hand, the refrigerant that has flowed from the high pressure gas pipe 41 into the second high pressure branch pipe 41b at the connection point A flows from the second four-way valve 22b through the second connection pipe 43b and into the second outdoor heat exchanger 23b. The refrigerant flowing into the second outdoor heat exchanger 23b melts the frost generated in the second outdoor heat exchanger 23b to become a liquid refrigerant or a gas-liquid two-phase refrigerant. Thus, the refrigerant that has flowed into the second outdoor heat exchanger 23b functioning as a condenser melts frost, and defrosting of the second outdoor heat exchanger 23b is performed.
The refrigerant that has flowed out of the second outdoor heat exchanger 23b flows through the second liquid distribution pipe 44b, is depressurized by the second outdoor expansion valve 24b, flows into the outdoor unit 2 from the indoor units 5a to 5c, and flows through the outdoor unit liquid pipe 44. The refrigerant joins at the connection point B.

  When the CPU 210 defrosts the second outdoor heat exchanger 23b, if the refrigerant temperature detected by the second heat exchange temperature sensor 35b is 10 ° C. or higher, or the first outdoor heat exchanger 23a. If a predetermined time (for example, 5 minutes) has elapsed since the start of the defrosting, it is determined that the defrosting of the second outdoor heat exchanger 23b has been completed, and the refrigerant circuit 100 is brought into the state shown in FIG. Return and continue heating operation.

  As described above, when the air conditioner 1 performs the defrosting operation, when the first outdoor heat exchanger 23a is functioning as a condenser to defrost the first outdoor heat exchanger 23a, the second outdoor When the heat exchanger 23b functions as an evaporator and the second outdoor heat exchanger 23b functions as a condenser to defrost the second outdoor heat exchanger 23b, the first outdoor heat exchanger 23a is an evaporator. Is functioning. As described above, the liquid refrigerant or the gas-liquid two-phase refrigerant that flows into one outdoor heat exchanger, melts frost, and flows out from the outdoor heat exchanger is the outdoor functioning as the other evaporator. It flows into the heat exchanger, evaporates and is sucked into the compressor 21. As a result, the liquid refrigerant or the gas-liquid two-phase refrigerant flowing out from the defrosted outdoor heat exchanger is not sucked into the compressor 21 as it is, so that a decrease in the discharge temperature of the compressor 21 can be suppressed, and the discharge temperature can be reduced. The defrosting time does not become longer due to the decrease.

  Moreover, the air conditioning apparatus 1 of the present invention includes the high pressure gas pipe 41 and the third four-way valve 25 in the outdoor unit 2, so that the first outdoor heat exchanger 23a is maintained while continuing the heating operation in the indoor units 5a to 5c. Or the 2nd outdoor heat exchanger 23b can be defrosted.

  In general, in an air conditioner in which an outdoor unit and an indoor unit are connected by two refrigerant pipes, a gas pipe and a liquid pipe, and the indoor unit performs either cooling or heating at the same time, the outdoor unit also has a gas pipe. And two refrigerant pipes, a liquid pipe and a liquid pipe. If it demonstrates concretely using FIG. 1, the refrigerant | coolant piping connected to the discharge side of the compressor 21 will be branched and connected to the 1st four-way valve 22a and the 2nd four-way valve 22b. Further, the suction side of the compressor 21 and the port c of the first four-way valve 22a and the port g of the second four-way valve 22b are connected by refrigerant piping, and the ports d and second of the closing valve 27 and the first four-way valve 22a are connected. A port h of the four-way valve 22b is connected by a refrigerant pipe. Here, the refrigerant pipe connecting the closing valve 27 and the port d of the first four-way valve 22a and the port h of the second four-way valve 22b is a gas pipe. The liquid pipe 44, the first liquid distribution pipe 44a, and the second liquid distribution pipe 44b are liquid pipes.

  In the refrigerant circuit as described above, for example, as shown in FIG. 5, the second outdoor heat exchanger 23b is switched so that the second outdoor heat exchanger 23b functions as a condenser, and the first outdoor heat exchanger 22a is an evaporator. When the first four-way valve 22a is switched to function as a part of the refrigerant, a part of the refrigerant discharged from the compressor 21 is a refrigerant that connects the first four-way valve 22a, the closing valve 27, and the port d of the first four-way valve 22a. Piping, refrigerant piping (gas pipe) connecting the closing valve 27 and the port h of the second four-way valve 22b, second refrigerant piping 22b, refrigerant piping connecting the suction port of the compressor 21 and the port g of the second four-way valve 22b There is a risk that the air flows into the compressor 21 and is sucked into the compressor 21.

  When the refrigerant discharged from the compressor 21 and flowing toward the indoor units 5a to 5c is sucked into the compressor 21 through the above-described path, there is a problem that the refrigerant does not flow into the indoor units 5a to 5c and cannot be heated. . However, like the air conditioner 1 of the present invention, the outdoor unit 2 includes the high-pressure gas pipe 41 and the third four-way valve 25, and the third four-way valve is connected so that the high-pressure gas pipe 41 and the gas pipe 9 are connected during heating operation. 25, a part of the refrigerant discharged from the compressor 21 flows through the high pressure gas pipe 41, the third four-way valve 25, the third refrigerant pipe 47, the closing valve 27, and the gas pipe 9 to ensure the indoor units 5a to 5a. Since it flows into 5c, defrosting of the 1st outdoor heat exchanger 23a or the 2nd outdoor heat exchanger 23b can be performed, performing heating operation.

  In the air conditioner 1 of the present embodiment, when the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b are arranged one above the other, for example, the first outdoor heat exchanger 23a is located on the upper side and the second outdoor heat exchanger 23b. When the heat exchangers 23b are respectively disposed on the lower side, it is desirable to perform defrosting from the first outdoor heat exchanger 23a disposed on the upper side. By first defrosting the first outdoor heat exchanger 23a, water generated by melting of the frost flows into the second outdoor heat exchanger 23b, and this water melts the frost of the second outdoor heat exchanger 23b. Can be dull. Moreover, since the defrosting of the 2nd outdoor heat exchanger 23b is performed following the defrosting of the 1st outdoor heat exchanger 23a, the water collected in the drain pan which is not shown arrange | positioned under the 2nd outdoor heat exchanger 23b Can be prevented from freezing.

  Moreover, when the heat exchanger capability of the 1st outdoor heat exchanger 23a and the 2nd outdoor heat exchanger 23b differs, for example, the direction of the 1st outdoor heat exchanger 23a is more heat exchanger capability than the 2nd outdoor heat exchanger 23b. When is large, it is desirable to defrost from the 1st outdoor heat exchanger 23a with large heat exchanger capability. This is for the reason described below.

  As in the present invention, at least one of the outdoor heat exchangers functions as a condenser to perform defrosting, and the other outdoor heat exchangers function as an evaporator to perform heating operation. When performing, the outdoor heat exchanger which functions as an evaporator becomes a heat source of the outdoor heat exchanger which defrosts. In the present embodiment, when the first outdoor heat exchanger 23a is defrosted, the second outdoor heat exchanger 23b serves as a heat source, and when the second outdoor heat exchanger 23b is defrosted, the first outdoor heat The exchanger 23a becomes a heat source.

  When defrosting the 2nd outdoor heat exchanger 23b first and then defrosting the 1st outdoor heat exchanger 23a, the 2nd outdoor which becomes a heat source in the case of defrosting the 1st outdoor heat exchanger 23a Since the heat exchanger 23b has a smaller heat exchanger capacity than the first outdoor heat exchanger 23a, the temperature of the second outdoor heat exchanger 23b tends to decrease. For this reason, there is a possibility that the time from when the defrosting operation is completed to when the second outdoor heat exchanger 23b is frosted and when the defrosting operation is started again is shortened.

  On the other hand, when the first outdoor heat exchanger 23a is first defrosted and then the second outdoor heat exchanger 23b is defrosted, the second outdoor heat exchanger 23b becomes a heat source during the defrosting. Since the 1 outdoor heat exchanger 23a has a larger heat exchanger capacity than the second outdoor heat exchanger 23b, the temperature of the first outdoor heat exchanger 23a is hardly lowered. At the same time, since the small second outdoor heat exchanger 23b is finally defrosted, frost is formed in the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b after the defrosting operation is completed. The time until the defrosting operation is generated again becomes longer than when the second outdoor heat exchanger 23b, which is initially small, is defrosted.

  Since the air conditioner of the present invention can defrost the outdoor heat exchanger while continuing the heating operation as described above, the heating operation is interrupted and the user is not uncomfortable. However, when performing the defrosting operation, part of the outdoor heat exchanger that functions as an evaporator during the heating operation functions as a condenser, so the heating capacity during the defrosting operation is the same as during normal heating operation. It will be lower. Therefore, it is desirable that the frequency of the defrosting operation is low, and for that purpose, it is better that the time from the end of the defrosting operation to the start of the next defrosting operation is long.

  Therefore, as described above, if the first outdoor heat exchanger 23a having a large heat exchanger capacity is first defrosted and then the second outdoor heat exchanger 23b having a small heat exchanger capacity is defrosted, Since the time until the defrosting operation is started again after the completion of the defrosting operation becomes longer and the frequency of the defrosting operation decreases, it is possible to suppress a decrease in heating capacity caused by this.

  As described above, in the air conditioning apparatus of the present invention, when performing defrosting of a plurality of outdoor heat exchangers during heating operation, other outdoor heat exchangers are defrosted while defrosting some of the outdoor heat exchangers. Since the heating operation is performed at the outdoor heat exchanger, the outdoor heat exchanger can be defrosted without interrupting the heating operation. Further, since the refrigerant flowing out from the outdoor heat exchanger to be defrosted is evaporated by the outdoor heat exchanger for heating and sucked into the compressor, the discharge temperature of the compressor is not lowered and the defrosting time can be shortened.

  In the embodiment described above, the case where there are two outdoor heat exchangers (the first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b) has been described, but three or more outdoor heat exchangers are provided. In this case, the defrosting may be performed sequentially. And when these three or more outdoor heat exchangers are arranged side by side, defrosting starts from the outdoor heat exchanger arranged at the top, and the lower outdoor heat exchangers are defrosted sequentially. To do. When the sizes of the three or more outdoor heat exchangers are different from each other, the defrosting is started from the largest outdoor heat exchanger, and the small outdoor heat exchangers are sequentially defrosted.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 5a-5c Indoor unit 8 Liquid pipe 9 Gas pipe 20 Outdoor unit refrigerant circuit 20a 1st outdoor heat exchanger unit 20b 2nd outdoor heat exchanger unit 21 Compressor 22a 1st four-way valve 22b 2nd Four-way valve 23a First outdoor heat exchanger 23b Second outdoor heat exchanger 25 Third four-way valve 41 High pressure gas pipe 41a First high pressure branch pipe 41b Second high pressure branch pipe 42 Low pressure gas pipe 42a First low pressure branch pipe 42b Second low pressure branch pipe 43a First connection pipe 43b Second connection pipe 44 Outdoor unit liquid pipe 44a First liquid distribution pipe 44b Second liquid distribution pipe 47 Outdoor unit gas pipe
51a-51c indoor heat exchanger 210 CPU
260 four-way valve switching section

Claims (3)

An air conditioner having a refrigerant circuit in which an outdoor unit and an indoor unit are connected by a liquid pipe and a gas pipe, and a control means,
The outdoor unit includes a compressor, a plurality of outdoor heat exchanger units, a high pressure gas pipe, a low pressure gas pipe, an outdoor unit gas pipe, an outdoor unit liquid pipe, and a second flow path switching unit.
The refrigerant discharge side of the compressor and the second flow path switching means are connected by the high pressure gas pipe,
The refrigerant suction side of the compressor and the second flow path switching means are connected by the low pressure gas pipe,
The gas pipe and the second flow path switching means are connected by the outdoor unit gas pipe,
The liquid pipe and the outdoor unit liquid pipe are connected,
The outdoor heat exchanger unit has an outdoor heat exchanger, a first flow path switching means, a high-pressure distribution pipe, a low-pressure distribution pipe, a liquid distribution pipe, and a connection pipe.
One refrigerant inlet / outlet of the outdoor heat exchanger and the first flow path switching means are connected by the connection pipe,
The other refrigerant inlet / outlet of the outdoor heat exchanger and the outdoor unit liquid pipe are connected by the liquid pipe,
The high pressure gas pipe and the first flow path switching means are connected by the high pressure branch pipe;
The low-pressure gas pipe and the first flow path switching means are connected by the low-pressure branch pipe;
The control means includes
When performing the heating operation, the first flow path switching unit of each outdoor heat exchanger unit is switched so that the outdoor heat exchanger of each outdoor heat exchanger unit functions as an evaporator, and the high-pressure gas pipe And switching the second flow path switching means so that the outdoor unit gas pipe is connected,
When performing the defrosting operation during the heating operation, the defrosting of the outdoor heat exchanger performed by switching the first flow path switching unit and causing the outdoor heat exchanger to function as a condenser is performed for each outdoor heat exchanger unit. And the outdoor heat exchanger unit that is not performing defrosting maintains the state during the heating operation.
An air conditioner characterized by that. The plurality of outdoor heat exchangers of the plurality of outdoor heat exchanger units are arranged side by side up and down,
When performing the defrosting operation during the heating operation, the control means starts the defrosting from the outdoor heat exchanger unit having the outdoor heat exchanger disposed at the top, and then sequentially lower layer outdoor heat exchange Defrosting an outdoor heat exchanger unit having a heater,
The air conditioner according to claim 1. The heat exchanger capabilities of the plurality of outdoor heat exchangers of the plurality of outdoor heat exchanger units are different,
When performing the defrosting operation during the heating operation, the control means starts defrosting from the outdoor heat exchanger unit having the outdoor heat exchanger having the largest heat exchanger capability, and then the heat exchanger capability is sequentially increased. Defrost outdoor heat exchanger unit with small outdoor heat exchanger,
The air conditioner according to claim 1.

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