JP6664503B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner capable of efficiently operating under high load conditions such as high outside air.

  In an air conditioner, in order to effectively use the performance of the heat exchanger and perform an operation to increase the efficiency, in the case of a condenser, reduce the number of branches and use it at a high flow rate, and in the case of an evaporator, It is effective to increase the number of branches and use at a low flow rate. The reason is that in the condenser, the flow-dependent heat transfer is dominant in improving the performance, and in the evaporator, reducing the flow-rate-dependent pressure loss is dominant in the performance. It is.

  A heat exchanger focusing on such characteristics of the condenser and the evaporator has been proposed in, for example, Japanese Patent Application Laid-Open No. 2015-117936 (Patent Document 1). This heat exchanger includes a flow path switching unit. The flow path switching unit switches the flow path so that the refrigerant flows in parallel to the plurality of flow paths when the heat exchanger is used as an evaporator, and when the heat exchanger is used as a condenser, The flow paths are switched so that the refrigerant flows in the order of the plurality of first flow paths and the plurality of second flow paths.

JP-A-2005-117936

  However, in the heat exchanger of the air conditioner disclosed in Japanese Patent Application Laid-Open No. 2015-117936 (Patent Document 1), the flow path configuration does not assume a supercooling region in the cooling operation, and the air conditioner does not operate in the cooling operation. There is a problem that the heat transfer performance when the refrigerant passes through the second flow path is reduced.

  For example, when operating with a high outdoor temperature and a high load on the air conditioner, the condensing temperature rises to secure the temperature difference between air and refrigerant to obtain the necessary supercooling at the condenser outlet during cooling. However, there is also a problem that the refrigerant pressure on the high pressure side increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to make a supercooling region of a condenser variable when performing a cooling operation, and to appropriately use the condenser according to a load. It is to provide an air conditioner.

  An air conditioner according to the present invention is an air conditioner in which a refrigerant circulates in the order of a compressor, a condenser, an expansion valve, and an evaporator. The condenser has a heat exchanger having a first refrigerant flow path and a second refrigerant flow path, and whether the refrigerant flows in the first refrigerant flow path and the second refrigerant flow path in order or in parallel. And a flow path switching unit configured to switch. The air conditioner includes an outdoor temperature detection unit that measures an outside air temperature, and a control device that controls switching of the flow path switching unit based on an output of the outdoor temperature detection unit.

  According to the present invention, the outdoor temperature detected by the outdoor temperature detection unit is used as a determination target value, and the flow path of the refrigerant flowing through the condenser of the air conditioner is changed to thereby change the flow path length or the refrigerant flow rate per refrigerant flow path. To adjust. Thereby, the condenser can be used efficiently even in a state where the liquid portion ratio occupying the inside of the condenser changes.

FIG. 1 is a schematic diagram showing an air conditioner 100 according to Embodiment 1 of the present invention. It is a perspective view of the example of a specific structure of an outdoor heat exchanger. It is the side view which looked at the outdoor heat exchanger of FIG. 2 from the Y direction. It is a figure for explaining a channel form of a three-way valve. 6 is a flowchart for explaining control by which a control device switches a flow path of a three-way valve. FIG. 4 is a diagram illustrating a flow of a refrigerant during a heating operation and during a cooling operation when Ta <T1. FIG. 4 is a diagram illustrating a flow of a refrigerant during a cooling operation when Ta> T1. FIG. 3 is a schematic diagram of a PH diagram when the air-conditioning apparatus 100 is operated for cooling at high outside air temperature and at low outside air temperature. It is a figure which shows the relationship between the dryness X of a refrigerant | coolant, and the heat transfer coefficient in a pipe | tube by a refrigerant | coolant. It is the schematic which shows the air conditioner 101 (heating / cooling at the time of low outside temperature) which concerns on the modification 1 of Embodiment 1. FIG. 3 is a schematic diagram showing an air conditioner 101 (cooling at high outside air temperature) according to a first modification of the first embodiment. FIG. 7 is a diagram for explaining opening / closing control of an electromagnetic valve in a first modification of the first embodiment. It is the schematic which shows the air conditioner 102 (heating / cooling at the time of low outside temperature) which concerns on the modification 2 of Embodiment 1. It is the schematic which shows the air conditioning apparatus 102 (cooling at the time of high outside temperature) which concerns on the modification 2 of Embodiment 1. It is the schematic which shows the air conditioner 103 (heating / cooling at the time of low outside temperature) which concerns on Embodiment 2. It is the schematic which shows the air conditioner 103 (cooling at the time of high outside temperature) which concerns on Embodiment 2. 13 is a flowchart for describing control executed in a third embodiment. 15 is a flowchart for describing control executed in a fourth embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following drawings, the size relationship of each component may be different from the actual one. Further, in the following drawings, the same reference numerals denote the same or corresponding components, and this is common in the entire text of the specification. Furthermore, the forms of the components shown in the entire text of the specification are merely examples, and the present invention is not limited to these descriptions.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram showing an air conditioner 100 according to Embodiment 1 of the present invention. As shown in FIG. 1, the air conditioner 100 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, an indoor heat exchanger 5, and a flow path switching unit 6. . The outdoor heat exchanger 3 includes a heat exchange unit 3a, a heat exchange unit 3b, and a heat exchange unit 3c. The flow path switching unit 6 includes a three-way valve 6a and a three-way valve 6b. The refrigerant circuit 90 is configured by connecting these components with, for example, piping.

  The compressor 1 is, for example, a variable capacity compressor that sucks and compresses refrigerant and discharges the refrigerant as high-temperature and high-pressure refrigerant.

  The four-way valve 2 is switching means that can switch the direction in which the refrigerant discharged from the compressor 1 flows, for example, in accordance with an operation command for a heating operation or a cooling operation. The four-way valve 2 is configured to connect a suction port and a discharge port of the compressor 1 to an indoor heat exchanger 5 and an outdoor heat exchanger 3, respectively, in a first flow path configuration (shown by a solid line in FIG. 1). A second flow path configuration (indicated by a broken line in FIG. 1) in which the suction port and the discharge port are connected to the outdoor heat exchanger 3 and the indoor heat exchanger 5, respectively. The first channel configuration (solid line) indicates a channel that communicates during cooling, and the second channel configuration (dashed line) indicates a channel that communicates during heating.

  Although the first and subsequent embodiments describe an air conditioner equipped with a four-way valve 2 for convenience of description, the present invention is also applied to an air conditioner not equipped with a four-way valve 2, for example, for cooling only. can do.

  The expansion valve 4 is configured to decompress and expand the refrigerant flowing out of the outdoor heat exchanger 3 during the cooling operation, and decompress and expand the refrigerant flowing out of the indoor heat exchanger 5 during the heating operation.

  The indoor heat exchanger 5 is a heat exchanger that functions as an evaporator during the cooling operation and functions as a condenser during the heating operation. The indoor heat exchanger 5 exchanges heat with the refrigerant flowing inside the indoor heat exchanger 5 by, for example, a fan 23 that blows indoor air or a pump (not shown) that supplies water or brine. The fan 23 and the pump are driven by a power supply device (not shown) for supplying electric power.

  In the refrigerant circuit configured as described above, in the present embodiment, the refrigerant flow path of the outdoor heat exchanger 3 is configured to be changeable.

  The outdoor heat exchanger 3 is a heat exchanger that functions as a condenser during a cooling operation and functions as an evaporator during a heating operation. The outdoor heat exchanger 3 exchanges heat with the refrigerant flowing inside the outdoor heat exchanger 3 by, for example, a fan 21 for supplying outside air, a pump (not shown) for supplying water or brine, or the like. The fan 21 and the pump are driven by a power supply device (not shown) for supplying electric power.

  The heat exchange units 3a, 3b, 3c included in the outdoor heat exchanger 3 are connected in series in the refrigerant circuit 90. The heat exchange section 3a is a main heat exchange section of the outdoor heat exchanger 3. The heat exchangers 3b and 3c serve as auxiliary heat exchangers (heat exchangers for ensuring supercooling) during cooling, and as root ice preventing heat exchangers that prevent freezing of the lower portion of the outdoor heat exchanger 3 during heating. used. For the sake of explanation, the heat exchanging sections 3a, 3b, 3c are shown in a divided state in the drawings, but they may be formed integrally. Further, the outdoor heat exchanger 3 includes only the heat exchange units 3a and 3b, and the heat exchange unit 3c may not be provided.

  FIG. 2 is a perspective view of a specific configuration example of the outdoor heat exchanger. FIG. 3 is a side view of the outdoor heat exchanger of FIG. 2 viewed from the Y direction. Referring to FIG. 2 and FIG. 3, in the outdoor heat exchanger of this configuration example, the refrigerant passages of the heat exchange portions 3a, 3b, 3c penetrate through a common fin.

  The heat exchange unit 3a is arranged at the top, the heat exchange unit 3c is arranged at the bottom, and the heat exchange unit 3b is arranged between the heat exchange unit 3a and the heat exchange unit 3c. In FIG. 2, the heat exchange unit 3b is not shown, and the entire outer shape of the outdoor heat exchanger 3 is shown by representatively showing the uppermost part of the heat exchange unit 3a and the lower part of the heat exchange unit 3c. Have been.

  Referring to FIGS. 1 and 3, outdoor heat exchanger 3 includes heat exchange units 3a, 3b, 3c, a flow path switching unit 6, and headers 41 to 47.

  The heat exchange section 3a includes refrigerant channels 31 and 32. The coolant channel 31 includes a coolant channel 31a and a coolant channel 31b through which the coolant flows in parallel. The coolant channel 32 includes a coolant channel 32a and a coolant channel 32b through which the coolant flows in parallel.

  The heat exchange section 3b includes refrigerant flow paths 33 and 34. The coolant channel 33 includes a coolant channel 33a and a coolant channel 33b through which the coolant flows in parallel. The coolant channel 34 includes a coolant channel 34a and a coolant channel 34b through which the coolant flows in parallel.

  The heat exchange section 3c includes a refrigerant channel 35. The coolant channel 35 includes a coolant channel 35a and a coolant channel 35b through which the coolant flows in parallel.

  For convenience of description, the direction in which the refrigerant flows in FIG. 3 will be referred to as the direction during cooling, and the internal flow paths of the three-way valves 6a and 6b will be described later as flow paths indicated by solid lines in FIG. The refrigerant flowing into the heat exchange section 3a and flowing in parallel with the refrigerant flow path 31a and the refrigerant flow path 31b joins in the header 41. The refrigerant flowing into the heat exchange section 3a and flowing in parallel with the refrigerant flow path 32a and the refrigerant flow path 32b joins at the header 42. The header 41 and the header 43 communicate with each other, and the refrigerant flows from the header 43 to the refrigerant flow paths 33a and 33b in parallel. The header 42 and the header 44 communicate with each other, and the refrigerant flows from the header 44 into the refrigerant flow paths 34a and 34b in parallel.

  The refrigerant flowing in parallel with the refrigerant passages 33a and 33b joins at the header 45. The refrigerant flowing in parallel with the refrigerant channels 34a and 34b joins at the header 46. The refrigerant that has passed through the header 45 and the refrigerant that has passed through the header 46 merge at the header 47. After passing through the header 47, the refrigerant flows into the refrigerant flow paths 35a and 35b in parallel.

  The flow switching unit 6 includes three-way valves 6a and 6b. Hereinafter, switching of these three-way valves will be described in detail.

  FIG. 4 is a diagram for explaining the flow path configuration of the three-way valve. Referring to FIGS. 1 and 4, the three-way valves 6a and 6b are for changing the number of refrigerant flow paths of the refrigerant flowing through the heat exchange section 3b by changing the internal flow path configuration. is there. When the flow direction of each of the three-way valves 6a and 6b is set to DA in the heat exchange unit 3b acting as a condenser during the cooling operation, the number of refrigerant flow paths through which the refrigerant flows in parallel is smaller than when the flow direction is set to DB. More.

  In the present embodiment, the flow path of the outdoor heat exchanger during cooling is switched depending on whether the outdoor temperature Ta detected by the outdoor temperature detection unit 11 is higher or lower than the threshold value T1. When Ta> T1, the flow path of the three-way valve is set so that the flow direction is DA, and when Ta <T1, the flow path of the three-way valve is set so that the flow direction is DB.

  Returning to FIG. 1 again, the outdoor temperature detector 11 is a sensor for detecting the temperature Ta outside the outdoor heat exchanger 3, and may use, for example, a thermistor. In the following description, “outdoor temperature” and “outside air temperature” refer to the temperature Ta outside the outdoor heat exchanger 3 detected by the outdoor temperature detection unit 11. The temperature detected by the outdoor temperature detection unit 11 is not limited to the temperature outside the outdoor heat exchanger 3 and may be, for example, the temperature of a heat medium such as water or brine.

  The control device 30 controls a compressor motor (not shown) to adjust the rotation speed of the compressor 1. Specifically, the control device 30 controls the compressor motor to change the rotation speed of the compressor 1 by changing the voltage or current input to the compressor motor. Further, the control device 30 controls the four-way valve 2 to switch the direction in which the refrigerant discharged from the compressor 1 flows through the refrigerant circuit 90. The control device 30 controls the outdoor motor to adjust the rotation speed of the fan 21. Specifically, the control device 30 controls the outdoor motor to change the rotation speed of the fan 21 by changing the voltage or current input to the outdoor motor.

  When the operation of the air conditioner 100 is started, the control device supplies power to the compressor motor of the compressor 1 and the outdoor motor of the fan 21 to control the rotation of the compressor 1 and the fan 21. The control device 30 includes, for example, a microcomputer or a circuit device mounted with a CPU in order to realize a function of controlling the compressor 1, the four-way valve 2, the expansion valve 4, the three-way valves 6a and 6b, the fan 21, and the like. , Or software executed by an arithmetic device such as a microcomputer or a CPU.

  When performing the cooling operation, control device 30 switches the internal flow path of four-way valve 2 so that the refrigerant discharged from compressor 1 flows to outdoor heat exchanger 3. Further, when performing the heating operation, the control device 30 switches the internal flow path of the four-way valve 2 so that the refrigerant discharged from the compressor 1 flows to the indoor heat exchanger 5.

  FIG. 5 is a flowchart for explaining control by which the control device 30 switches the flow path of the three-way valve. The process of this flowchart is called from a main routine and executed at regular intervals or every time a predetermined condition is satisfied.

  Referring to FIGS. 1 and 5, control device 30 first determines whether a cooling operation or a heating operation is specified in step S1. When the cooling operation is designated, the process of step S2 is executed, and when the heating operation is designated, the process of step S5 is executed.

  In step S2, the control device 30 detects the external temperature Ta of the outdoor heat exchanger 3 using the outdoor temperature detection unit 11. In step S3 following step S2, control device 30 determines whether or not external temperature Ta is higher than determination temperature T1. In step S3, the control device 30 executes the process of step S4 if Ta> T1, and executes the process of step S5 if Ta> T1.

  In step S4, the control device 30 controls the three-way valves 6a and 6b so that the flow direction of the three-way valve is set to DB. On the other hand, in step S5, the control device 30 controls the three-way valves 6a and 6b so that the flow direction of the three-way valve is DA.

  When the flow direction of the three-way valve is determined in step S4 or S5, the process returns to the main routine.

  Next, the flow of the refrigerant when the air-conditioning apparatus 100 operates will be described with reference to FIGS. FIG. 6 is a diagram illustrating the flow of the refrigerant during the heating operation and during the cooling operation when Ta <T1. FIG. 7 is a diagram illustrating the flow of the refrigerant during the cooling operation when Ta> T1.

  When performing the cooling operation, first, the refrigerant discharged from the compressor 1 flows into the heat exchange unit 3a via the four-way valve 2. During the cooling operation, the heat exchange unit 3a functions as a condenser. The refrigerant that has flowed into the heat exchange unit 3a performs heat exchange with the air supplied to the heat exchange unit 3a by the fan 21.

  When the refrigerant is set in the flow paths of the three-way valves 6a and 6b so as to flow in the flow direction DA of FIG. 4, the refrigerant flowing into the heat exchange unit 3b flows out of the heat exchange unit 3a as shown in FIG. After passing through the heat exchanging section 3b with the same number of refrigerant flow paths as in the state, the refrigerant flow paths are merged and flow into the heat exchanging section 3c.

  In this case, in the specific example of FIG. 3, the number of the refrigerant flow paths 31a, 31b, 32a, 32b flowing out of the heat exchange section 3a is 4, and the refrigerant flow paths 33a, 33b passing through the heat exchange section 3b in parallel. , 34a, 34b is four, and the number of refrigerant flow paths 35a, 35b passing in parallel through the heat exchange part 3c is two.

  On the other hand, when the refrigerant is set to flow in the flow direction DB in the flow paths of the three-way valves 6a and 6b, as shown in FIG. 7, the refrigerant passes through the refrigerant flow path in the heat exchange unit 3a and exits at the outlet. After joining, they flow into the heat exchange section 3b. Then, the refrigerant passes through the heat exchange section 3b with a smaller number of refrigerant flow paths than the heat exchange section 3a, and passes through the heat exchange section 3c with the same number of refrigerant flow paths as the heat exchange section 3b.

  In this case, in the specific example of FIG. 3, the number of refrigerant flow paths flowing out of the heat exchange unit 3a is 4, the number of refrigerant flow paths passing in parallel through the heat exchange unit 3c is 2, and the flow direction is DA. However, the number of refrigerant channels that pass through the heat exchanger 3b simultaneously and in parallel is two. That is, in the heat exchange section 3b, the refrigerant passes in parallel with the refrigerant channels 33a and 33b, and then passes in parallel with the refrigerant channels 34a and 34b. Decrease from 4 to 2.

  Returning to FIG. 6 and FIG. 7, the refrigerant that has undergone heat exchange in the outdoor heat exchanger 3 flows out of the outdoor heat exchanger 3 and flows into the expansion valve 4. The refrigerant flowing into the expansion valve 4 is depressurized by the expansion valve 4 and then flows out of the expansion valve 4. The refrigerant flowing out of the expansion valve 4 flows into the indoor heat exchanger 5 functioning as an evaporator during the cooling operation, and exchanges heat with the air supplied from the fan 23 to the inside of the indoor heat exchanger 5. The refrigerant that has exchanged heat in the indoor heat exchanger 5 flows into the compressor 1 via the four-way valve 2.

  As described above, during the cooling operation, the number of flow paths flowing in parallel in the heat exchange unit 3b is increased or decreased based on the outside air temperature Ta. On the other hand, during the heating operation, the number of flow paths flowing in parallel in the heat exchange section 3b is fixed so that the refrigerant flows as indicated by the dashed arrow in FIG.

  Next, the reason for switching the refrigerant flow path of the outdoor heat exchanger 3 during the cooling operation based on the outside air temperature Ta will be described.

  In the case where the air-conditioning apparatus 100 performs the cooling operation and the outside air temperature is high, the controller 30 generally increases the speed of the compressor 1 in order to satisfy the air conditioning load requirement on the indoor unit side. By increasing the speed of the compressor 1, the amount of circulating refrigerant discharged from the compressor 1 also increases.

  FIG. 8 is a schematic diagram of a PH diagram when the air-conditioning apparatus 100 performs the cooling operation at the time of the high outside temperature and at the time of the low outside temperature. In general, when the cooling operation is performed at a high outdoor temperature, the condensation temperature of the refrigerant in the outdoor heat exchanger 3 increases in order to secure a difference between the outdoor air temperature and the refrigerant temperature of the refrigerant flowing through the outdoor heat exchanger 3. As the condensing temperature rises, the refrigerant pressure on the high pressure side also rises as indicated by the broken line cycle C1 in FIG. On the other hand, when the cooling operation is performed at a low outside air temperature, the temperature difference between the air temperature and the refrigerant temperature can be secured even when the condensation temperature is low. Drops. The refrigerant pressure on the high pressure side also decreases as shown by the cycle C2 of the solid line in FIG.

  Generally, as a characteristic of a refrigerant used in an air conditioner, in a state where temperature is high, that is, in a state where pressure is high, latent heat is reduced. The state of the gas part of the refrigerant is Rg, the two-phase part is Rs, and the liquid part is RL, and the enthalpy difference in each state is ΔH (Rg), ΔH (Rs), and ΔH (RL). When the same degree of supercooling is ensured, ΔH (RL) is substantially constant without changing according to the pressure (ΔH (RL) 1 = ΔH (RL) 2 in FIG. 8). On the other hand, ΔH (Rs) decreases as the pressure increases (ΔH (Rs) 1 <ΔH (Rs) 2 in FIG. 8).

  For this reason, the enthalpy difference ratio α (= ΔH (RL) / ΔH (Rs)) between the liquid portion and the two-phase portion increases as the outside air temperature increases. The air-conditioning apparatus 100 may operate so as to secure a degree of subcooling at the outlet of the outdoor heat exchanger 3 in order to secure the capacity during the cooling operation or to maximize the operation efficiency. If the control device 30 controls the air conditioner 100 with the same degree of supercooling as the target, the enthalpy difference ratio α between the liquid part and the two-phase part inside the outdoor heat exchanger 3 increases the outside air temperature. Will increase in accordance with. That is, the area where the inside of the outdoor heat exchanger 3 is filled with the liquid is large.

  FIG. 9 is a diagram showing a relationship between the dryness X of the refrigerant and the heat transfer coefficient in the pipe by the refrigerant. As shown in FIG. 9, the heat transfer coefficient in the pipe of the refrigerant varies depending on the degree of dryness, generally has a high peak in the two-phase part, and has a single-phase part (gas (X = 1) or liquid (X = 0) )) Tend to be low. Therefore, even when passing through the outdoor heat exchanger 3 in the air conditioner 100, since a phase change (dryness change) occurs in the outdoor heat exchanger 3, a portion having a good heat transfer coefficient and a portion having a bad heat transfer coefficient are obtained. Exists.

  In consideration of the above-described state, in a state where the enthalpy difference ratio α is large (high outside air temperature), the length of the flow path per refrigerant flow path of the outdoor heat exchanger 3 is increased, and the heat transfer by improving the flow velocity in the pipe is performed. Promote efficient driving. In a state in which the enthalpy difference α is small (low outside air temperature), the length of the two-phase portion having a high heat transfer coefficient in the pipe is increased by shortening the flow path per refrigerant flow path of the outdoor heat exchanger 3. Promote heat and perform efficient operation.

  Specifically, in the air-conditioning apparatus 100 according to Embodiment 1, in order to easily determine the enthalpy difference ratio α, the outside air temperature Ta detected by the outdoor temperature detection unit 11 is set to a threshold T1. In comparison, the three-way valves 6a and 6b are switched to make the refrigerant flow path of the refrigerant flowing through the heat exchange unit 3b variable as shown in FIG.

  By employing the above variable flow path, when the outdoor temperature Ta is higher than the predetermined temperature T1, the flow path per refrigerant flow path of the heat exchange unit 3b is compared with the case where the outdoor temperature Ta is lower than the predetermined temperature T1. Can be long. Therefore, it is possible to use the outdoor heat exchanger 3 suitable for each operation state. Therefore, when the air-conditioning apparatus 100 is operated, an improvement in air-conditioning capacity and an improvement in efficiency can be expected, or an effect on device reliability by suppressing high pressure and suppressing discharge temperature can be expected.

  The technology applied to the air-conditioning apparatus 100 in the first embodiment is not limited to a plate-fin type air-type heat exchanger that exchanges heat with air, but a plate-type heat exchange that exchanges heat with water or brine. This technology is applicable to vessels.

  In the air-conditioning apparatus 100 according to Embodiment 1, for convenience of description, FIGS. 1, 6, and 7 are mainly used to describe the simple refrigerant circuit 90. For example, FIGS. As described above, it is possible to adopt a configuration of a heat exchanger in which distribution headers are arranged at the entrance and exit of the outdoor heat exchanger and the indoor heat exchanger, and a liquid storage device such as a receiver or an accumulator for ensuring reliability. May be used as the refrigerant circuit.

  Further, in the air-conditioning apparatus 100 according to Embodiment 1, mainly in the cooling operation, the configuration is described in which the outside air temperature is a determination target value and the refrigerant flow path flowing through the heat exchange unit 3b is variable. Alternatively, the coolant flow path may be variable as needed.

  Although the description may partially overlap, the first embodiment described above will be summarized with reference to the drawings.

  The air conditioner 100 shown in FIG. 1 is an air conditioner in which a refrigerant circulates in the order of a compressor 1, a condenser (outdoor heat exchanger 3), an expansion valve 4, and an evaporator (indoor heat exchanger 5). . The condenser allows the refrigerant to flow through the outdoor heat exchanger 3 having the refrigerant flow path 33 and the refrigerant flow path 34 and the refrigerant flow path 33 and the refrigerant flow path 34 in order (direction DB) or to flow the refrigerant in parallel. (Direction DA). The air-conditioning apparatus 100 includes an outdoor temperature detection unit 11 that measures an outside air temperature Ta, and a control device 30 that controls switching of the flow path switching unit 6 based on an output of the outdoor temperature detection unit 11.

  As shown in FIG. 5, preferably, when the detection value Ta of the outdoor temperature detecting unit 11 is lower than the threshold value T1, the control device 30 controls the refrigerant flow path 33 and the refrigerant flow path 34 in parallel. The flow path switching unit 6 is controlled so that the refrigerant flows, and when the detection value Ta of the outdoor temperature detection unit 11 is higher than the threshold value T1, the refrigerant that has passed through the refrigerant flow path 33 flows to the refrigerant flow path 34. The flow switching unit 6 is controlled as described above.

  As shown in FIGS. 1 and 3, preferably, the outdoor heat exchanger 3 has a heat exchange portion 3a, a heat exchange capacity smaller than the heat exchange portion 3a, and a heat exchange portion 3a in a path through which the refrigerant circulates. And a heat exchange section 3b connected to the downstream side. The heat exchange section 3b includes a coolant channel 33 and a coolant channel 34.

  In the example shown in FIG. 3, the cross-sectional areas of the refrigerant pipes of each heat exchange unit are the same, the number of heat exchange units 3a is 48, and the number of heat exchange units 3b is eight. Therefore, more preferably, the heat exchange capacity of the heat exchange unit 3a is at least twice the heat exchange capacity of the heat exchange unit 3b. More preferably, as shown in FIG. 3, the ratio of the total length of the refrigerant pipes of the heat exchange section 3a to the total length of the refrigerant pipes of the heat exchange section 3b is 6: 1.

  As shown in FIG. 1, preferably, the outdoor heat exchanger 3 includes a heat exchange unit 3a, a heat exchange unit 3b disposed downstream of the heat exchange unit 3a in a path in which the refrigerant circulates, and the refrigerant circulates. And a heat exchange unit 3c disposed downstream of the heat exchange unit 3b in the path. The heat exchange section 3b includes a coolant channel 33 and a coolant channel 34. The heat exchange section 3a includes a refrigerant flow path 31 and a refrigerant flow path 32 through which the refrigerant flows in parallel. The heat exchange section 3c has a refrigerant channel 35. The outlet of the coolant channel 31 communicates with the inlet of the coolant channel 33, and the outlet of the coolant channel 34 communicates with the inlet of the coolant channel 35. The three-way valve 6b that switches whether the outlet of the coolant channel 33 communicates with the inlet of the coolant channel 35 or the outlet of the coolant channel 34, and the outlet of the coolant channel 32 And a three-way valve 6a for switching between communication with the inlet of the refrigerant channel 33 and communication with the inlet of the refrigerant channel 34.

Modification 1 of Embodiment 1
In the first embodiment, the configuration in which the three-way valves 6a and 6b are used to change the refrigerant flow path of the heat exchange unit 3b is described. In a first modification of the first embodiment, another configuration in which the refrigerant flow path of the heat exchange unit 3b is variable will be described.

  FIG. 10 is a schematic diagram showing an air conditioner 101 (heating / cooling at low outside temperature) according to a first modification of the first embodiment. FIG. 11 is a schematic diagram showing an air conditioner 101 (cooling at high outside air temperature) according to a first modification of the first embodiment.

  As shown in FIGS. 10 and 11, the air conditioner 101 includes a compressor 1, a four-way valve 2, a heat exchange unit 3a, a heat exchange unit 3b, a heat exchange unit 3c, an expansion valve 4, The refrigerant circuit 91 is configured by connecting the indoor heat exchanger 5 and the solenoid valves 7a, 7b, 7c, and 7d by, for example, piping.

  The outdoor heat exchanger 3 includes a heat exchange unit 3a, a heat exchange unit 3b disposed downstream of the heat exchange unit 3a in a refrigerant circulation path, and a heat exchange unit 3b downstream of the heat exchange unit 3b in a refrigerant circulation path. And a heat exchange unit 3c to be disposed. The heat exchange section 3b includes a coolant channel 33 and a coolant channel 34. The heat exchange section 3a includes a refrigerant flow path 31 and a refrigerant flow path 32 through which the refrigerant flows in parallel. The heat exchange section 3c has a refrigerant channel 35. The outlet of the coolant channel 31 communicates with the inlet of the coolant channel 33, and the outlet of the coolant channel 34 communicates with the inlet of the coolant channel 35.

  The air conditioner 101 includes a flow path switching unit 7 instead of the flow path switching unit 6 in the configuration of the air conditioner 100 shown in FIG. 1, and the other parts are the same. In the first modification of the first embodiment, the flow path switching unit 7 includes a solenoid valve 7a, a solenoid valve 7b, a solenoid valve 7c, and a solenoid valve 7d.

  The solenoid valve 7d switches whether or not the outlet of the coolant channel 33 communicates with the inlet of the coolant channel 35. The solenoid valve 7a switches whether or not the outlet of the coolant channel 32 communicates with the inlet of the coolant channel 34. The solenoid valve 7c switches whether or not the outlet of the coolant channel 33 communicates with the inlet of the coolant channel 34. The solenoid valve 7 b switches whether or not the outlet of the coolant channel 32 communicates with the inlet of the coolant channel 33.

  FIG. 12 is a diagram for describing opening / closing control of an electromagnetic valve according to the first modification of the first embodiment.

  When the outdoor temperature Ta is lower than the predetermined temperature T1, the control device 30 opens the solenoid valve 7a, closes the solenoid valve 7b, closes the solenoid valve 7c, and opens the solenoid valve 7d so as to open the solenoid valve 7d. Control. FIG. 10 shows the flow of the refrigerant in this case.

  On the other hand, when the outdoor temperature Ta is higher than the predetermined temperature T1, the control device 30 closes the solenoid valve 7a, opens the solenoid valve 7b, opens the solenoid valve 7c, and closes the solenoid valve 7d. 7 is controlled. The flow of the refrigerant in this case is shown in FIG.

  By controlling the solenoid valve according to the opening / closing pattern shown in FIG. 12, when the outdoor temperature Ta is higher than the predetermined temperature T1, one refrigerant flow in the heat exchange unit 3b is compared with the case where the outdoor temperature Ta is lower than the predetermined temperature T1. The length of the flow path per road can be increased. Therefore, it is possible to use the outdoor heat exchanger 3 suitable for each operation state. Therefore, when the air-conditioning apparatus 101 is operated, an improvement in air-conditioning capacity and an improvement in efficiency can be expected, or an effect on device reliability due to suppression of high pressure and suppression of discharge temperature can be expected.

Modification 2 of Embodiment 1
In the first embodiment, the configuration in which the three-way valves 6a and 6b are used to change the refrigerant flow path of the heat exchange unit 3b is described. In a second modification of the first embodiment, another configuration in which the refrigerant flow path of the heat exchange unit 3b is variable will be described.

  FIG. 13 is a schematic diagram showing an air conditioner 102 (heating / cooling at low outside air temperature) according to a second modification of the first embodiment. FIG. 14 is a schematic diagram showing an air conditioner 102 (cooling at high outside air temperature) according to a second modification of the first embodiment.

  As shown in FIG. 13 and FIG. 14, the air conditioner 102 includes a compressor 1, a four-way valve 2, a heat exchange unit 3a, a heat exchange unit 3b, a heat exchange unit 3c, an expansion valve 4, The refrigerant circuit 92 is configured by connecting the indoor heat exchanger 5 and the solenoid valves 9a, 9b, the check valves 10a, and the check valves 10b by, for example, piping.

  The outdoor heat exchanger 3 includes a heat exchange unit 3a, a heat exchange unit 3b disposed downstream of the heat exchange unit 3a in a refrigerant circulation path, and a heat exchange unit 3b downstream of the heat exchange unit 3b in a refrigerant circulation path. And a heat exchange unit 3c to be disposed. The heat exchange section 3b includes a coolant channel 33 and a coolant channel 34. The heat exchange section 3a includes a refrigerant flow path 31 and a refrigerant flow path 32 through which the refrigerant flows in parallel. The heat exchange section 3c has a refrigerant channel 35. The outlet of the coolant channel 31 communicates with the inlet of the coolant channel 33, and the outlet of the coolant channel 34 communicates with the inlet of the coolant channel 35.

  The air conditioner 102 includes a flow path switching unit 9 instead of the flow path switching unit 6 in the configuration of the air conditioner 100 shown in FIG. 1, and the other parts are the same. In the second modification of the first embodiment, the flow path switching unit 9 includes a solenoid valve 9a, a solenoid valve 9b, a check valve 10a, and a check valve 10b.

  The solenoid valve 9b switches whether or not the outlet of the coolant channel 33 communicates with the inlet of the coolant channel 35. The solenoid valve 9a switches whether or not the outlet of the coolant channel 32 communicates with the inlet of the coolant channel 34. The check valve 10b is disposed between the outlet of the refrigerant channel 33 and the inlet of the refrigerant channel 34, and is configured to flow the refrigerant from the outlet of the refrigerant channel 33 toward the inlet of the refrigerant channel 34. . The check valve 10a is disposed between the outlet of the refrigerant channel 32 and the inlet of the refrigerant channel 33, and is configured to flow the refrigerant from the outlet of the refrigerant channel 32 toward the inlet of the refrigerant channel 33. .

  In the above air conditioner 102, the control device 30 changes the opening / closing pattern of the solenoid valves 9a and 9b in order to make the refrigerant flow path of the heat exchange unit 3b variable.

  When the outdoor temperature Ta is lower than the predetermined temperature T1, the control device 30 controls the flow path switching unit 9 to open the solenoid valve 9a and open the solenoid valve 9b. The flow of the refrigerant in this case is shown in FIG.

  On the other hand, when the outdoor temperature Ta is higher than the predetermined temperature T1, the control device 30 controls the flow path switching unit 9 to close the solenoid valve 9a and close the solenoid valve 9b. FIG. 14 shows the flow of the refrigerant in this case.

  By opening and closing the solenoid valve as described above, when the outdoor temperature Ta is higher than the predetermined temperature T1, the flow per one refrigerant flow path of the heat exchange unit 3b is compared with the case where the outdoor temperature Ta is lower than the predetermined temperature T1. The road can be lengthened. Therefore, it is possible to use the outdoor heat exchanger 3 suitable for each operation state. Therefore, when the air-conditioning apparatus 102 is operated, an improvement in air-conditioning capacity and an improvement in efficiency can be expected, or an effect on device reliability due to suppression of high pressure and suppression of discharge temperature can be expected. Further, since the check valve does not require a control signal and is smaller in size than the electromagnetic valve, the configuration of the outdoor heat exchanger can be simplified.

Embodiment 2 FIG.
In the first embodiment, the configuration in which the three-way valves 6a and 6b are used to change the refrigerant flow path of the heat exchange unit 3b is described. The heat exchange unit 3b according to the first embodiment is connected in series with the heat exchange unit 3a, and a refrigerant flow variable system of the heat exchange unit 3b after being connected in series has been proposed. In the second embodiment, a heat exchange unit 3d is provided instead of the heat exchange unit 3b. In the second embodiment, a system in which the heat exchange unit 3a and the heat exchange unit 3d are arranged in series or in parallel and the refrigerant flow path is variable will be described.

  FIG. 15 is a schematic diagram showing an air conditioner 103 (heating / cooling at low outside air temperature) according to Embodiment 2. FIG. 16 is a schematic diagram showing an air conditioner 103 (cooling at high outside air temperature) according to Embodiment 2.

  As shown in FIGS. 15 and 16, the air conditioner 103 includes a compressor 1, a four-way valve 2, a heat exchange unit 3 a, a heat exchange unit 3 d, a heat exchange unit 3 c, an expansion valve 4, and a room. The refrigerant circuit 93 is configured by connecting the heat exchanger 5 and the flow path switching valve 8 with, for example, piping.

  In the second embodiment, the passage switching unit is the passage switching valve 8 provided with the inlet P1, the inlet P2, the outlet P3, and the outlet P4. By moving the valve body up and down, the flow path switching valve 8 forms a flow pattern PA (FIG. 15) at two inlets and two outlets and a flow pattern PB at one inlet and one outlet at the refrigerant flow path. (FIG. 16).

  The inlet P1 communicates with the inlet of the heat exchange unit 3a, and the inlet P3 communicates with the outlet of the heat exchange unit 3a. The outlet P3 communicates with the inlet of the heat exchange unit 3d, and the outlet P4 communicates with the outlet of the heat exchange unit 3d. When the position of the valve element in the flow path switching valve 8 is set to the first position, the flow path switching valve 8 forms a first flow path (PB) that receives the refrigerant from the inlet P2 and flows the refrigerant to the outlet P3. When the position of the valve element in the flow path switching valve 8 is set to the second position, the refrigerant is received from the inlet P1 and flows to the outlet P3, and the refrigerant is received from the inlet P2 and flows to the outlet P4. It is configured to form two flow paths (PA).

  In the air-conditioning apparatus 103, by changing the flow pattern of the flow path switching valve 8 between PA and PB, the refrigerant flow path can be changed so that the heat exchange section 3a and the heat exchange section 3d are connected in parallel or in series. I do. In the case of the flow pattern PA of the flow path switching valve 8, the flow path is formed such that the refrigerant flows in parallel to the heat exchange section 3d and the heat exchange section 3a. In the case of the flow pattern PB of the flow path switching valve 8, a flow path is formed so that the refrigerant flows in series with the heat exchange section 3d and the heat exchange section 3a.

  When the heat exchange unit 3d is connected in series with the heat exchange unit 3a, the flow rate of the refrigerant per refrigerant flow path increases. When the heat exchange unit 3d is connected in parallel with the heat exchange unit 3a, the flow rate of the refrigerant per one refrigerant flow path decreases.

  By configuring the variable flow path by the flow path switching valve 8, when the outdoor temperature Ta is higher than the predetermined temperature T 1, the outdoor temperature Ta is lower than the predetermined temperature T 1. The flow path per refrigerant flow path can be lengthened. Therefore, it is possible to use the outdoor heat exchanger 3 suitable for each operation state. Therefore, when the air-conditioning apparatus 101 is operated, an improvement in air-conditioning capacity and an improvement in efficiency can be expected, or an effect on device reliability due to suppression of high pressure and suppression of discharge temperature can be expected.

Embodiment 3 FIG.
In the air-conditioning apparatuses described in Embodiments 1 and 2, switching the flow path using the flow path switching means using the outdoor temperature Ta detected by the outdoor temperature detection means as the determination target value has been described. The air conditioner according to the third aspect is characterized in that the flow path is switched using the operating frequency f of the compressor 1 as a determination target value. That is, in the third embodiment, control device 30 performs switching determination of the flow path switching unit based on operating frequency f of compressor 1.

  When the operating frequency f of the compressor 1 is high, the amount of circulating refrigerant flowing in the refrigerant circuit increases. When the refrigerant circulation amount increases, the amount of heat that can be processed in the outdoor heat exchanger 3 decreases, and in order to secure a temperature difference with air, the condensing temperature increases, and the high-pressure side refrigerant pressure increases. When the operating frequency of the compressor 1 is low, the condensing temperature decreases, and the high-pressure side refrigerant pressure also decreases. This tendency is the same as the case where the outdoor temperature Ta is high and the case where the outdoor temperature Ta is low in the air conditioner described in the first embodiment. Therefore, in the third embodiment, the same processing as in the air conditioners described in the first and second embodiments is performed using the operating frequency of the compressor 1 as the determination target value.

  In the third embodiment, when the operating frequency f of the compressor 1 is higher than the threshold value f1, the control device 30 selects one of the flow path switching units 6, 7, and 9 of the first embodiment, or Using the flow path switching valve 8 of the second aspect, the flow path per refrigerant flow path flowing through the outdoor heat exchanger 3 is made longer or the flow rate is increased.

  On the other hand, when the compressor operating frequency f is lower than the threshold value f1, the control device 30 selects one of the flow path switching units 6, 7, and 9 of the first embodiment or the flow path switching of the second embodiment. By using the valve 8, the flow path per refrigerant flow path flowing to the outdoor heat exchanger 3 is shortened or the flow rate is reduced.

  FIG. 17 is a flowchart for explaining control executed in the third embodiment. The processing of this flowchart is obtained by applying flow path switching based on the operating frequency of the compressor 1 to the first embodiment shown in FIG. The process of this flowchart is called from a main routine and executed at regular intervals or every time a predetermined condition is satisfied.

  Referring to FIG. 17, control device 30 first determines in step S11 whether a cooling operation or a heating operation has been designated. When the cooling operation is designated, the process of step S12 is executed, and when the heating operation is designated, the process of step S14 is executed.

  In step S12, control device 30 determines whether or not operating frequency f of compressor 1 is higher than threshold value f1. In step S12, the control device 30 executes the process of step S13 if f> f1, and executes the process of step S14 if f> f1.

  In step S13, the control device 30 controls the three-way valves 6a and 6b so that the flow direction of the three-way valve is set to DB. On the other hand, in step S14, the control device 30 controls the three-way valves 6a and 6b so that the flow direction of the three-way valve is set to DA.

  When the flow direction of the three-way valve is determined in step S13 or S14, the process returns to the main routine.

  According to the above configuration and control, when the operating frequency f of the compressor 1 is higher than the predetermined threshold value f1, the outdoor heat is higher than when the operating frequency f of the compressor 1 is lower than the predetermined threshold value f1. The flow path per refrigerant flow path of the exchanger 3 can be lengthened, or the flow rate can be increased, and the outdoor heat exchanger 3 suitable for each operation state can be used. Therefore, when operating the air-conditioning apparatus, it is possible to expect an improvement in performance, an improvement in efficiency, an effect on device reliability by suppressing high pressure and suppressing discharge temperature, and the like.

  Note that, instead of the three-way valve, the above-described control may be applied to the configurations of Modification 1 (electromagnetic valve) and Modification 2 (electromagnetic valve and check valve) of Embodiment 1, and Embodiment 2 The above control may be applied to the configuration of the switching valve.

Embodiment 4 FIG.
In the air-conditioning apparatuses according to Embodiments 1 and 2, switching of the flow path is described with the outdoor temperature Ta detected by the outdoor temperature detecting unit 11 as the determination target value. However, in the air-conditioning apparatus of Embodiment 4, Is characterized in that a flow path is switched by calculating a difference between a set temperature and a temperature detection unit that detects a load side arrival temperature, and using the difference as a determination target value. As this detection unit, a temperature detection unit 12 that detects the temperature Tj of the air blown out of the indoor heat exchanger 5 in FIG. 1 can be used. Can be.

  In the air-conditioning apparatus according to Embodiment 4, control device 30 calculates ΔT = | Tm−Tj | at outlet temperature Tj and target set temperature Tm. The control device 30 calculates a difference between the load-side reached temperature Tj and the set temperature Tm, and determines switching of the flow path switching unit 6 based on the output of the outdoor temperature detection unit 11 and the difference.

  Specifically, when ΔT is larger than threshold value ΔT1, control device 30 determines that the load-side reached temperature has not reached the target reached temperature, and air conditioner 105 determines, for example, that compressor 1 , Or by adjusting the degree of opening of the expansion valve 4 so as to reach the target temperature early.

  If ΔT is larger than the threshold value ΔT1, it is considered that the high-pressure side refrigerant pressure increases or the condensing temperature increases in order to reach the target. Means for switching means are required.

  When ΔT is larger than threshold value ΔT1, control device 30 controls flow path switching unit 6 in the air-conditioning apparatus according to Embodiments 1 to 3, which makes the refrigerant flow path flowing to outdoor heat exchanger 3 variable. To increase the flow path per refrigerant flow path flowing through the outdoor heat exchanger 3 or increase the flow rate.

  On the other hand, when ΔT is smaller than threshold value ΔT1, control device 30 switches the flow path of the air-conditioning apparatus according to the first to third embodiments so that the refrigerant flow path flowing to outdoor heat exchanger 3 is variable. By using the part 6, the flow path per refrigerant flow path flowing to the outdoor heat exchanger 3 is shortened or the flow rate is reduced.

  FIG. 18 is a flowchart for illustrating control executed in the fourth embodiment. The processing of this flowchart is obtained by applying the flow path switching based on the blowing temperature Tj to the first embodiment shown in FIG. The process of this flowchart is called from a main routine and executed at regular intervals or every time a predetermined condition is satisfied.

  Referring to FIG. 18, control device 30 first determines in step S21 whether a cooling operation or a heating operation is specified. When the cooling operation is designated, the process of step S22 is executed, and when the heating operation is designated, the process of step S26 is executed.

  In step S22, the control device 30 causes the temperature detection unit 12 to detect the temperature Tj of the air blown from the indoor heat exchanger 5. In step S23 following step S22, the control device 30 calculates ΔT = | Tm−Tj | at the blowing temperature Tj and the target set temperature Tm. Then, in a step S24, it is determined whether or not the difference value ΔT is higher than the threshold value ΔT1. In step S24, control device 30 executes the process of step S25 if ΔT> ΔT1, and executes the process of step S26 if ΔT> ΔT1.

  In step S25, the control device 30 controls the three-way valves 6a and 6b so that the flow direction of the three-way valve is set to DB. On the other hand, in step S26, the control device 30 controls the three-way valves 6a and 6b so that the flow direction of the three-way valve is set to DA.

  When the flow direction of the three-way valve is determined in step S25 or S26, the process returns to the main routine.

  With the above configuration and control, when ΔT is higher than threshold value ΔT1, the flow path per refrigerant flow path of outdoor heat exchanger 3 is longer than when ΔT is lower than threshold value ΔT1, or , The flow rate can be increased, and the outdoor heat exchanger 3 suitable for each operation state can be used. Therefore, when operating the air-conditioning apparatus, it is possible to expect an improvement in performance, an improvement in efficiency, an effect on device reliability by suppressing high pressure and suppressing discharge temperature, and the like.

  In the above first to fourth embodiments, the flow path of the indoor heat exchanger is switched using the outdoor temperature Ta, the compressor frequency f, and the difference ΔT between the load-side reached temperature Tj and the set temperature Tm as the determination target value, respectively. The configuration has been described. In the first to fourth embodiments, the refrigerant flow path is made variable using a single determination target value, but these determination target values may be used in combination. When the determination is made by combining a plurality of determination target values, for example, when one of the plurality of determination target values becomes higher than the determination value, the flow direction can be switched from DA to DB.

  Note that, instead of the three-way valve, the above-described control may be applied to the configurations of Modification 1 (electromagnetic valve) and Modification 2 (electromagnetic valve and check valve) of Embodiment 1, and Embodiment 2 The above control may be applied to the configuration of the switching valve.

  The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 four-way valve, 3 outdoor heat exchanger, 3a, 3b, 3c, 3d heat exchange part, 4 expansion valve, 5 indoor heat exchanger, 6, 7, 9 flow path switching part, 6a, 6b three-way valve , 7a, 7b, 7c, 7d, 9a, 9b solenoid valve, 8 flow path switching valve, 10a, 10b check valve, 11 outdoor temperature detecting section, 12 temperature detecting section, 21, 23 fan, 30 control device, 31, 31a, 31b, 32, 32a, 32b, 33, 33a, 33b, 34, 34a, 34b, 35, 35a, 35b Refrigerant flow path, 41-47 header, 90-93 refrigerant circuit, 100-105 Air conditioner.

Claims (10)

An air conditioner in which a refrigerant circulates in the order of a compressor, a condenser, an expansion valve, and an evaporator,
The condenser comprises:
A heat exchanger having a first refrigerant flow path and a second refrigerant flow path,
Outdoor temperature is the flow of the refrigerant sequentially into the second refrigerant flow path and the first coolant channel is higher than a predetermined temperature, said first refrigerant flow when the outdoor temperature is lower than the predetermined temperature parallel to said second coolant flow path and including a flow path switching unit configured to flow the refrigerant, the air conditioner. The flow path switching unit , when the outdoor temperature is lower than a first threshold value , flows the refrigerant in parallel with the first refrigerant flow path and the second refrigerant flow path, and the outdoor temperature is wherein the higher than first threshold, to flow the refrigerant passed through the first refrigerant flow to the second refrigerant passage, the air conditioning apparatus according to claim 1. The heat exchanger comprises:
A first heat exchange section;
A heat exchange capacity smaller than the first heat exchange unit, and a second heat exchange unit connected to the downstream side of the first heat exchange unit in a path in which the refrigerant circulates,
The air conditioner according to claim 1, wherein the second heat exchange unit includes the first refrigerant flow path and the second refrigerant flow path.   The air conditioner according to claim 3, wherein the heat exchange capacity of the first heat exchange unit is at least twice the heat exchange capacity of the second heat exchange unit.   The air conditioner according to claim 4, wherein a ratio of a total length of the refrigerant pipes of the first heat exchange section to a total length of the refrigerant pipes of the second heat exchange section is 6: 1. The heat exchanger comprises:
A first heat exchange section;
A second heat exchange unit disposed downstream of the first heat exchange unit in a path in which the refrigerant circulates,
A third heat exchange section disposed downstream of the second heat exchange section in a path in which the refrigerant circulates,
The second heat exchange unit includes the first refrigerant flow path and the second refrigerant flow path,
The first heat exchange unit includes a third refrigerant flow path and a fourth refrigerant flow path through which the refrigerant flows,
The third heat exchange unit has a fifth refrigerant flow path,
An outlet of the third coolant channel communicates with an inlet of the first coolant channel,
An outlet of the second coolant channel communicates with an inlet of the fifth coolant channel,
The flow path switching unit,
A first three-way valve that switches whether the outlet of the first refrigerant flow path communicates with the inlet of the fifth refrigerant flow path or the communication with the inlet of the second refrigerant flow path;
2. A second three-way valve that switches between an outlet of the fourth refrigerant flow passage and an inlet of the first refrigerant flow passage or a communication with an inlet of the second refrigerant flow passage. 3. 3. The air conditioner according to 2. The heat exchanger comprises:
A first heat exchange section;
A second heat exchange unit disposed downstream of the first heat exchange unit in a path in which the refrigerant circulates,
A third heat exchange section disposed downstream of the second heat exchange section in a path in which the refrigerant circulates,
The second heat exchange unit includes the first refrigerant flow path and the second refrigerant flow path,
The first heat exchange unit includes a third refrigerant flow path and a fourth refrigerant flow path through which the refrigerant flows,
The third heat exchange unit has a fifth refrigerant flow path,
An outlet of the third coolant channel communicates with an inlet of the first coolant channel,
An outlet of the second coolant channel communicates with an inlet of the fifth coolant channel,
The flow path switching unit,
A first solenoid valve for switching whether or not the outlet of the first refrigerant flow path communicates with the inlet of the fifth refrigerant flow path;
A second solenoid valve for switching whether or not the outlet of the fourth refrigerant flow path communicates with the inlet of the second refrigerant flow path;
A third solenoid valve for switching whether or not the outlet of the first refrigerant flow path communicates with the inlet of the second refrigerant flow path;
3. The air conditioner according to claim 1, further comprising: a fourth solenoid valve that switches whether or not the outlet of the fourth coolant channel communicates with the inlet of the first coolant channel. 4. The heat exchanger comprises:
A first heat exchange section;
A second heat exchange unit disposed downstream of the first heat exchange unit in a path in which the refrigerant circulates,
A third heat exchange section disposed downstream of the second heat exchange section in a path in which the refrigerant circulates,
The second heat exchange unit includes the first refrigerant flow path and the second refrigerant flow path,
The first heat exchange unit includes a third refrigerant flow path and a fourth refrigerant flow path through which the refrigerant flows,
The third heat exchange unit has a fifth refrigerant flow path,
An outlet of the third coolant channel communicates with an inlet of the first coolant channel,
An outlet of the second coolant channel communicates with an inlet of the fifth coolant channel,
The flow path switching unit,
A first solenoid valve for switching whether or not the outlet of the first refrigerant flow path communicates with the inlet of the fifth refrigerant flow path;
A second solenoid valve for switching whether or not the outlet of the fourth refrigerant flow path communicates with the inlet of the second refrigerant flow path;
The refrigerant is disposed between an outlet of the first refrigerant flow passage and an inlet of the second refrigerant flow passage so that the refrigerant flows from the outlet of the first refrigerant flow passage toward the inlet of the second refrigerant flow passage. A configured first check valve;
Disposed between the outlet of the fourth coolant channel and the inlet of the first coolant channel, so that the coolant flows from the outlet of the fourth coolant channel toward the inlet of the first coolant channel. The air conditioner according to claim 1 or 2, further comprising a second check valve configured. The heat exchanger comprises:
A first heat exchange section;
A heat exchange capacity smaller than the first heat exchange unit, and a second heat exchange unit connected to the downstream side of the first heat exchange unit in a path in which the refrigerant circulates,
The flow path switching unit is a switching valve provided with a first inlet, a second inlet, a first outlet, and a second outlet,
The first inlet communicates with an inlet of the first heat exchange unit,
The second inlet communicates with an outlet of the first heat exchange unit,
The first outlet communicates with an inlet of the second heat exchange unit,
The second outlet communicates with an outlet of the second heat exchange unit,
The switching valve is configured to form a first flow path that receives a refrigerant from the second inlet and flows to the first outlet when a position of a valve element in the switching valve is set to a first position. , the position of the valve body in the changeover valve when set to the second position, the with flow to the first outlet receives the refrigerant from the first inlet, the second outlet receiving refrigerant from said second inlet The air-conditioning apparatus according to claim 1, wherein the air-conditioning apparatus is configured to form a second flow path flowing through the air conditioner. An outdoor temperature detection unit that measures the outdoor temperature,
A load-side temperature detector that detects a load-side reached temperature ;
A control device that controls switching of the flow path switching unit ,
The control device according to claim 1, wherein the control device calculates a difference between the load-side reached temperature and a set temperature, and performs switching determination of the flow path switching unit based on the output of the outdoor temperature detection unit and the difference. The air conditioner according to any one of the preceding claims.

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