JP5494280B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner, and more particularly to a technique for determining an operation failure of the four-way switching valve provided in a refrigerant circuit.

  The four-way switching valve provided in the refrigerant circuit of the air conditioner switches the communication state of the four ports so that the high-temperature gas refrigerant discharged from the compressor flows into the outdoor heat exchanger or Switch to one of the indoor heat exchangers. This four-way switching valve is configured to perform the switching operation by being driven by a differential pressure between a high pressure port communicating with the discharge side of the compressor and a low pressure port communicating with the suction side.

  However, if the differential pressure between the high pressure port and the low pressure port is insufficient, the four-way switching valve may malfunction. In order to detect the malfunction of the four-way switching valve, for example, an air conditioner disclosed in Patent Document 1 includes a pressure sensor for detecting the refrigerant pressure at each port of the four-way switching valve, and a switching operation determination unit. The switching operation determining means includes the refrigerant pressure on the heat source side connection port side when the refrigerant pressure on the heat source side connection port side is not as low as the refrigerant pressure on the low pressure port side, or not as high as the refrigerant pressure on the high pressure port side. Sometimes it is determined that the switching operation is defective.

JP-A-6-50642

  However, in the air conditioner disclosed in Patent Document 1, a pressure sensor is required for each port of the four-way switching valve. Further, since the pressure sensor is expensive compared to other sensors (for example, temperature sensors), it is preferable to reduce the number of the pressure sensors provided from the viewpoint of cost reduction.

  The present invention has been made to solve such a conventional problem, and reduces the manufacturing cost without providing a pressure sensor at each port of the four-way switching valve. The purpose is to enable detection of defects.

An air conditioner according to claim 1 of the present invention includes an indoor heat exchanger (31), an outdoor heat exchanger (22), a compressor (40), a four-way switching valve (21), an expansion valve ( 24) and a refrigerant circuit (10) connected by refrigerant piping;
An indoor heat exchanger temperature detector (85) provided in the indoor heat exchanger (31) for detecting the temperature of the indoor heat exchanger (31);
An outdoor heat exchanger temperature detection unit (76) provided in the outdoor heat exchanger (22) for detecting the temperature of the outdoor heat exchanger (22);
A controller (91) for outputting a port switching signal to the four-way switching valve (21) and controlling port switching of the four-way switching valve (21);
After the port switching signal is output by the control unit (91), the temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detection unit (85) is within a predetermined first range. The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) falls outside a predetermined second range, and The four-way switching valve when the temperature of the heat exchanger (31) and the temperature of the outdoor heat exchanger (22) satisfy a switching failure determination condition that they do not reverse within a predetermined period. It is an air conditioning apparatus provided with the switching failure determination part (92) determined to be port switching failure of (21).

  In the case where a port switching failure occurs in the four-way switching valve (21) and the port is not switched to a predetermined port, for example, a port to be closed is not completely closed and a port to be opened is opened only incompletely. Since the refrigerant flowing through the refrigerant circuit cannot normally flow to the planned route, even if the port switching signal is output from the control unit (91) to the four-way switching valve (21), the indoor heat exchanger (31) and The temperature of the outdoor heat exchanger (22) does not reach the planned temperature within the scheduled time. Furthermore, the phenomenon that the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are reversed does not occur.

  Based on this, in the present invention, the temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detecting unit (85) falls below a predetermined first range, The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the heat exchanger temperature detection unit (76) falls below a predetermined second range, and the temperature of the indoor heat exchanger (31) When the switching failure determination condition that the temperature of the outdoor heat exchanger (22) and the temperature of the outdoor heat exchanger (22) do not reverse within a predetermined period is satisfied, the port switching failure of the four-way switching valve (21) is determined. Further, it is possible to determine the port switching failure of the four-way switching valve (21) without the need for pressure sensors such as the low pressure side and high pressure side pressure detection sensors of the compressor and the heat source side refrigerant pressure detection sensor.

  That is, (1) The temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detector (85) after the port switching signal of the four-way selector valve (21) is output is determined in advance. The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) is within a predetermined second range, In addition, when the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are reversed within a predetermined period, the phenomenon causes the refrigerant circulation direction to change as planned. Therefore, it is assumed that the switching of the condensation and evaporation by the indoor heat exchanger (31) and the outdoor heat exchanger (22) is completed within the scheduled period, so that the four-way switching valve (21) It can be determined that the switching is normally performed.

  (2) The rate of temperature change of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detector (85) after the port switching signal is output from the four-way switching valve (21) is determined in advance. The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) falls below the first range, and falls below the predetermined second range. In the case where the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are reversed within a predetermined period, the reversed phenomenon is as expected. Although the refrigerant circulation direction has been switched and it has exceeded the scheduled period, it is assumed that the effects of condensation and evaporation by the indoor heat exchanger (31) and the outdoor heat exchanger (22) have been switched normally. Therefore, the switching of the four-way selector valve (21) itself is performed normally. It can be determined that

  (3) After the port switching signal is output from the four-way selector valve (21), the temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detector (85) is predetermined. Although the temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) is within the first range, the temperature change rate is within a predetermined second range. When the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) do not reverse within a predetermined period, any of the problems of the four-way switching valve (21) and the compressor (40) It cannot be judged whether it is.

  On the other hand, (4) The temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detecting unit (85) after the port switching signal of the four-way switching valve (21) is output is determined in advance. The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) falls outside the first range and falls below the predetermined second range. If the switching failure determination condition that the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) do not reverse within a predetermined period is satisfied, the indoor heat exchanger ( The phenomenon in which the temperature of 31) and the temperature of the outdoor heat exchanger (22) are not reversed is that the circulation direction of the refrigerant is not switched as planned, and the indoor heat exchanger (31) and the outdoor heat exchanger Condensation and evaporation due to (22) are not switching normally. Therefore, it can be determined that at least the port switching of the four-way switching valve (21) is defective.

  An air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect, wherein the switching failure determination unit (92) is detected by the indoor heat exchanger temperature detection unit (85). The temperature change rate of the temperature of the indoor heat exchanger (31) falls below a third range determined based on a temperature change rate smaller than the predetermined first range, and the outdoor heat exchange A temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the temperature detector (76) is determined based on a temperature change rate that is smaller than the predetermined second range. Switching failure determination condition that the temperature is lower than the range of the temperature and the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are not reversed within a predetermined period. If the compressor (40) malfunctions, It is intended to determine that that.

  When the port is switched by the four-way switching valve (21), even if the heat exchange scheduled in the refrigerant circuit is not performed due to the malfunction of the compressor (40), the indoor heat exchanger (31) and the outdoor heat exchanger ( The temperature of 22) does not reach the planned temperature within the scheduled time, but in this case, refrigerant compression by the compressor (40) is performed only insufficiently, so the indoor heat exchanger (31 at this time) ) And the temperature change rate of the temperature of the outdoor heat exchanger (22) are further smaller than when the port switching failure occurs in the four-way switching valve (21). For this reason, in the present invention, the temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detection unit (85) is a temperature change rate that is even smaller than the predetermined first range. The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) is less than the third range determined based on the Switching that falls below a fourth range determined based on a temperature change rate that is smaller than the range, and that the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are not reversed. By determining that the compressor (40) has malfunctioned when the failure determination condition is satisfied, the four-way switching can be performed without providing a pressure sensor at each port of the four-way switching valve (21). Whether there is a port switching failure in the valve (21) It can be determined by distinguishing whether cause malfunction to the compressor (40).

An air conditioner according to claim 3 of the present invention includes an indoor heat exchanger (31), an outdoor heat exchanger (22), a compressor (40), a four-way selector valve (21), and the indoor heat. A refrigerant circuit (10) in which an expansion valve (24) provided between the exchanger (31) and the outdoor heat exchanger (22) is connected by a refrigerant pipe;
An indoor heat exchanger temperature detector (85) provided in the indoor heat exchanger (31) for detecting the temperature of the indoor heat exchanger (31);
An outdoor heat exchanger temperature detection unit (76) provided in the outdoor heat exchanger (22) for detecting the temperature of the outdoor heat exchanger (22);
A discharge temperature detection unit (75) that is provided on the discharge side of the compressor (40) in the refrigerant circuit (10) and detects the temperature of the refrigerant discharged from the compressor (40);
A suction temperature detection unit (73) provided on the suction side of the compressor (40) in the refrigerant circuit (10) for detecting the temperature of the refrigerant sucked into the compressor (40);
A control unit (91) for outputting a port switching signal to the drive unit of the four-way switching valve (21) and controlling the port switching of the four-way switching valve (21);
The temperature of the discharge refrigerant detected by the discharge temperature detection unit (75) and the temperature of the intake refrigerant detected by the suction temperature detection unit (73) after the port switching signal is output by the control unit (91). The difference is less than a predetermined temperature difference, and the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are not reversed within a predetermined period. In this case, the air conditioner includes a switching failure determination unit (92) that determines that the port switching of the four-way switching valve (21) is defective.

  According to the present invention, a port switching failure occurs in the four-way switching valve (21), and the port is not switched to a predetermined port. For example, the port to be closed is not completely closed, and the port to be opened is only opened incompletely. In such a case, since the refrigerant flowing through the refrigerant circuit cannot normally flow through the planned route, even if a port switching signal is output from the control unit (91) to the four-way switching valve (21), the compressor There is no planned temperature difference between the discharged refrigerant temperature and the intake refrigerant temperature of (40). Furthermore, the phenomenon that the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are reversed does not occur.

  Based on this, in the present invention, after the switching failure determination unit outputs the port switching signal by the control unit (91), the temperature difference between the discharge refrigerant temperature and the suction refrigerant temperature of the compressor (40) is determined in advance. By determining that the port switching failure of the four-way switching valve (21) is below the difference and the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are not reversed. Further, it is possible to determine the port switching failure of the four-way switching valve (21) without the need for pressure sensors such as the low pressure side and high pressure side pressure detection sensors of the compressor and the heat source side refrigerant pressure detection sensor.

An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first aspect, wherein the air conditioner is provided on a discharge side of the compressor (40) in the refrigerant circuit (10), and the compressor ( 40) a discharge temperature detection unit (75) for detecting the temperature of the refrigerant discharged from
A suction temperature detector (73) provided on the suction side of the compressor (40) in the refrigerant circuit (10) and detecting the temperature of the refrigerant sucked into the compressor (40);
The switching failure determination unit (92) satisfies the switching failure determination condition and outputs the temperature of the discharged refrigerant detected by the discharge temperature detection unit (75) after the port switching signal is output by the control unit (91). When the temperature difference with the temperature of the suction refrigerant detected by the suction temperature detection unit (73) is less than a predetermined temperature difference, it is determined that the port switching failure of the four-way switching valve (21). To do.

  According to the present invention, in addition to satisfying the above switching failure determination condition, when the condition that the temperature difference between the discharge refrigerant temperature and the suction refrigerant temperature of the compressor (40) is less than a predetermined temperature difference is satisfied. Moreover, the accuracy of the switching failure determination is enhanced by determining that the port switching failure of the four-way switching valve (21) is detected.

  According to the present invention, it is possible to detect a malfunction of the four-way switching valve without using a pressure sensor, and it is possible to reduce the manufacturing cost of the air conditioner.

It is a refrigerant circuit figure showing a schematic structure of an air harmony device concerning one embodiment of the present invention. It is sectional drawing which shows schematic structure of a four-way selector valve. It is a block diagram which shows schematic structure of a controller. It is a flowchart which shows 1st Embodiment of the switching failure determination process of the four-way switching valve by an air conditioning apparatus. It is a figure which shows transition of the indoor heat exchanger temperature and the outdoor heat exchanger temperature after switching a four-way switching valve from the port state about heating operation to the port state about cooling operation, (a) is four-way switching The figure which shows the case where a valve operate | moves normally, (b) is a figure which shows the case where a four-way selector valve is a malfunctioning. (A) is a figure which shows the normal state of the slide valve of a four-way selector valve at the time of heating operation, (b) is a figure which shows the normal state of the slide valve of the four-way selector valve at the time of cooling operation, (c) is It is a figure which shows the malfunctioning state of the slide valve of a four-way selector valve. It is a flowchart which shows 2nd Embodiment of the switching failure determination process of the four-way switching valve by an air conditioning apparatus. It is a figure which shows transition of the refrigerant | coolant discharge refrigerant | coolant temperature and suction | inhalation refrigerant | coolant temperature of a compressor after switching a four-way switching valve from the port state at the time of heating operation to the port state at the time of cooling operation, (a) is a four-way switching valve. The figure which shows the case where is operated normally, (b) is a figure which shows the case where a four-way selector valve is malfunctioning. It is a flowchart which shows 3rd Embodiment of the switching failure determination process of the four-way switching valve by an air conditioning apparatus. It is a flowchart which shows the pump down completion determination process by an air conditioning apparatus. It is a block diagram which shows schematic structure of the controller with which the air conditioning apparatus which performs pump down completion determination is provided.

  Hereinafter, an air conditioner according to an embodiment of the present invention and a switching failure determination method for a four-way switching valve will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is a refrigerant circuit diagram illustrating a schematic configuration of an air-conditioning apparatus according to an embodiment of the present invention. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 2 and an indoor unit 3. The air conditioner 1 also includes a refrigerant circuit 10 that performs a vapor compression refrigeration cycle by circulating the refrigerant.

  The refrigerant circuit 10 includes an outdoor circuit 20, an indoor circuit 30, a liquid side communication pipe 16, and a gas side communication pipe 17. The outdoor circuit 20 and the indoor circuit 30 are connected via a liquid side communication pipe 16 and a gas side communication pipe 17.

  The outdoor circuit 20 is housed in the outdoor unit 2. The outdoor circuit 20 is provided with a compressor 40, a four-way switching valve 21, an outdoor heat exchanger 22, an expansion valve 24, an accumulator 23, a liquid side closing valve 25, and a gas side closing valve 26.

  The compressor 40 is, for example, a hermetic scroll compressor. The compressor 40 is configured by housing a compression mechanism and an electric motor that drives the compression mechanism in a cylindrical housing. The detailed illustration of the compression mechanism and the electric motor is omitted. The compressor 40 is configured to be variable in capacity by changing the rotational speed of the electric motor stepwise or continuously under the control of the control unit 91 described later.

  A suction pipe 43 that is a low-pressure gas pipe and a discharge pipe 44 that is a high-pressure gas pipe are respectively connected to the compressor 40. In the suction pipe 43, the refrigerant sucked into the compressor 40 flows. The refrigerant discharged from the compressor 40 flows through the discharge pipe 44. The inlet end of the suction pipe 43 is connected to the port P4 of the four-way switching valve 21 via the accumulator 23, and the outlet end thereof is connected to the suction side of the compressor 40. The discharge pipe 44 has an inlet end connected to the discharge side of the compressor 40 and an outlet end connected to a port P1 through an oil separator.

  The outdoor heat exchanger 22 is configured by, for example, a cross fin type fin-and-tube heat exchanger. In the outdoor heat exchanger 22, the refrigerant circulating in the refrigerant circuit 10 and the outdoor air exchange heat. A flow divider 27 is provided at the other end of the outdoor heat exchanger 22 and connected to the liquid side communication pipe 16 by piping. The outdoor fan 70 sends outdoor air to the outdoor heat exchanger 22.

  The accumulator 23 is a cylindrical container, and stores the separated liquid refrigerant so that the liquid refrigerant and the gas refrigerant are separated and the gas refrigerant is sucked into the compressor 40. The accumulator 23 is provided in a suction pipe 43 that connects the four-way switching valve 21 and the compressor 40.

  The outdoor unit 2 is provided with various sensors. Specifically, the outdoor unit 2 is provided with an outside air temperature sensor 71 for detecting the temperature of the outdoor air sucked into the outdoor unit 2. In the outdoor unit 2, the flow divider 27 located at one end of the outdoor heat exchanger 22 is provided with a temperature sensor 72 (deisathermistor) for detecting the tube temperature of the flow divider 27. The outdoor heat exchanger 22 is provided with an outdoor heat exchanger temperature sensor 76 for detecting the refrigerant temperature inside the outdoor heat exchanger 22. The outdoor heat exchanger temperature sensor 76 detects the condensation temperature during the cooling operation described later, and detects the evaporation temperature during the heating operation. Further, a liquid pipe temperature sensor 61 is provided between the expansion valve 24 and the liquid side closing valve 25. A pipe between the expansion valve 24 and an indoor heat exchanger 31 described later is hereinafter referred to as a liquid refrigerant pipe 11. The liquid side communication pipe 16 described above is included in the liquid refrigerant pipe 11. The liquid pipe temperature sensor 61 detects the temperature of the liquid refrigerant pipe 11 in the portion where the liquid pipe temperature sensor 61 is provided.

  The intake pipe 43 of the compressor 40 has an intake refrigerant temperature sensor for detecting the intake temperature, which is the temperature of the refrigerant sucked into the compressor 40 (for example, detecting the temperature of the intake pipe 43 as the temperature of the intake refrigerant). 73 (intake temperature detection unit) is provided. The discharge pipe 44 is provided with a discharge refrigerant temperature sensor 75 (discharge temperature) for detecting a discharge temperature that is the temperature of the refrigerant discharged from the compressor 40 (for example, detecting the temperature of the discharge pipe 44 as the temperature of the discharge refrigerant). Detection section) is provided.

  Furthermore, the outdoor unit 2 is provided with a controller 90. The controller 90 controls the operation of the air conditioner 1 in response to signals from the sensors and a command signal from a remote controller or the like.

  The indoor unit 3 is provided with an indoor circuit 30. The indoor circuit 30 is provided with an indoor heat exchanger 31. The indoor heat exchanger 31 is configured by, for example, a cross fin type fin-and-tube heat exchanger. In the indoor heat exchanger 31, the refrigerant circulating in the refrigerant circuit 10 and the room air exchange heat. Furthermore, the indoor unit 3 is provided with an indoor fan 80. The indoor fan 80 sends room air to the indoor heat exchanger 31.

  One end of the liquid side communication pipe 16 is connected to the liquid side closing valve 25, and the other end is connected to a flow divider 32 that is one end side of the indoor heat exchanger 31 in the indoor circuit 30. One end of the gas side communication pipe 17 is connected to the gas side closing valve 26, and the other end is connected to the other end side of the indoor heat exchanger 31. The pipe between the four-way switching valve 21 and the indoor heat exchanger 31 is hereinafter referred to as a gas refrigerant pipe 12. The gas side communication pipe 17 is included in the gas refrigerant pipe 12.

  The indoor unit 3 is provided with a temperature sensor and a humidity sensor. Specifically, the indoor unit 3 is provided with a suction air temperature sensor 81, a shunt temperature sensor 84, and an indoor heat exchanger temperature sensor 85. The intake air temperature sensor 81 detects the temperature of the indoor air sucked into the indoor unit 3, that is, the intake air temperature of the indoor unit 3. The shunt temperature sensor 84 is provided in the shunt 32 located at one end of the indoor heat exchanger 31 and detects the tube temperature of the shunt 32. The indoor heat exchanger temperature sensor 85 detects the refrigerant temperature inside the indoor heat exchanger 31. That is, the indoor heat exchanger temperature sensor 85 detects the evaporation temperature during the cooling operation described later, and detects the condensation temperature during the heating operation.

  FIG. 2 is a diagram showing a schematic configuration of the four-way switching valve 21. The four-way switching valve 21 includes a valve body 212 having a discharge port P1, two switching ports P3, P2 connected to the discharge side of the compressor, and a suction port P4 connected to the suction side of the compressor 40, and the inside thereof. The valve seat 213, the slide valve (port switching valve) 214, and the pistons 215 and 216 for switching the connection destination of the switching ports P3 and P2 are included. The slide valve 214 is biased by the spring 217 so as to maintain the state shown in FIG. 2, that is, the state in which the switching port P3 is electrically connected to the suction port P4 and the switching port P2 is electrically connected to the discharge port P1. When the pilot valve 218 is switched by passing an electric current through the coil 219, the piston 216 side is sucked, and the slide valve 214 is slid rightward in FIG. 2 with respect to the valve seat 213, and is switched to the switching ports P3 and P2. Can be switched so that the suction port P4 and the discharge port P1 are conductive.

  In the four-way switching valve 21, the port P <b> 3 is connected to the gas side closing valve 26 by piping, and the port P <b> 2 is connected to one end of the outdoor heat exchanger 22 by piping. The four-way switching valve 21 is configured such that the port P1 and the port P2 communicate with each other, the port P3 and the port P4 communicate with each other (the state indicated by the solid line in FIG. 1), the port P1 and the port P3 communicate with each other, and The state is switched to a state where P2 and port P4 communicate with each other (a state indicated by a broken line in FIG. 1). By the switching operation of the four-way switching valve 21, the refrigerant circulation direction in the refrigerant circuit 10 is reversed.

  FIG. 3 is a block diagram illustrating a schematic configuration of the controller 90. The controller 90 includes a control unit 91, a switching failure determination unit 92, and an input reception unit 93.

  The control unit 91 performs operation control of the air conditioner 1. That is, the control unit 91 performs adjustment of the opening degree of the expansion valve 24, switching of the four-way switching valve 21, driving control of the compressor 40 (rotational speed control), air volume control of the outdoor fan 70 and the indoor fan 80, and the like.

  The switching failure determination unit 92 outputs the temperature change rate of the temperature of the indoor heat exchanger 31 detected by the indoor heat exchanger temperature sensor 85 and the outdoor heat exchange after the port switching signal is output to the four-way switching valve 21 by the control unit 91. Whether the temperature change rate of the temperature of the outdoor heat exchanger 22 detected by the outdoor temperature sensor 76 falls outside a predetermined range, and further, the temperature of the indoor heat exchanger 31 and the outdoor temperature Based on the determination as to whether or not the switching failure determination condition of whether or not the temperature of the heat exchanger 22 is reversed is satisfied, whether or not the port switching of the four-way switching valve 21 is defective, and further, the compressor 40 It is determined whether or not is malfunctioning.

  Further, the switching failure determination unit 92 outputs the temperature of the discharged refrigerant detected by the discharged refrigerant temperature sensor 75 and the suction detected by the suction refrigerant temperature sensor 73 after the port switching signal is output to the four-way switching valve 21 by the control unit 91. When the temperature difference with the refrigerant temperature is less than a predetermined temperature difference and the temperature of the indoor heat exchanger 31 and the temperature of the outdoor heat exchanger 22 are not reversed, the four-way switching valve 21 Is determined to be defective.

  Further, the switching failure determination unit 92 has a built-in timer 921 that can measure an elapsed time from when the control unit 91 outputs the port switching signal to the four-way switching valve 21.

  Next, the operation of the air conditioner 1 will be described. When the air conditioner 1 is in operation, the refrigerant circulates while changing phase in the refrigerant circuit 10 to perform a vapor compression refrigeration cycle. The air conditioner 1 performs a cooling operation and a heating operation.

  << Cooling Operation >> During the cooling operation, the indoor heat exchanger 31 functions as an evaporator, and a cooling operation is performed. During the cooling operation, the four-way switching valve 21 is in a state indicated by a solid line in FIG. The expansion valve 24 is adjusted to a predetermined opening degree by the controller 91 of the controller 90.

  When the compressor 40 is operated, the refrigerant compressed by the compressor 40 is discharged to the discharge pipe 44. This discharged refrigerant passes through the four-way switching valve 21 and flows into the outdoor heat exchanger 22. In the outdoor heat exchanger 22, the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant is then sent to the compressor 40 from the liquid side communication pipe 16 to the indoor circuit 30.

  The refrigerant that has flowed into the indoor circuit 30 is introduced into the indoor heat exchanger 31. In the indoor heat exchanger 31, the refrigerant absorbs heat from the indoor air and evaporates. That is, the refrigerant introduced into the indoor circuit 30 evaporates in the indoor heat exchanger 31, and as a result, the indoor air is cooled.

  The refrigerant evaporated in the indoor heat exchanger 31 flows into the outdoor circuit 20 through the gas side communication pipe 17. Thereafter, the refrigerant passes through the four-way switching valve 21 and is sucked into the compressor 40 through the suction pipe 43 and the accumulator 23. The compressor 40 compresses the sucked refrigerant and discharges it again. In the refrigerant circuit 10, such circulation of the refrigerant is repeated.

  The controller 91 of the controller 90 adjusts the opening degree of the expansion valve 24 as described above. At that time, the control unit 91 adjusts the opening degree of the expansion valve 24 so that the degree of superheat of the gas refrigerant flowing out of the indoor heat exchanger 31 and sucked into the compressor 40 becomes constant. Specifically, the opening degree of the expansion valve 24 is appropriately changed so that the difference between the detected temperature of the intake refrigerant temperature sensor 73 and the detected temperature of the indoor heat exchanger temperature sensor 85 is maintained at a predetermined value.

  << Heating Operation >> During the heating operation, the indoor heat exchanger 31 functions as a condenser, and a heating operation is performed. During the heating operation, the four-way switching valve 21 is in a state indicated by a broken line in FIG. The expansion valve 24 is adjusted to a predetermined opening.

  When the compressor 40 is operated, the refrigerant compressed by the compressor 40 is discharged to the discharge pipe 44. The refrigerant flows from the four-way switching valve 21 toward the gas-side closing valve 26 and flows into the indoor circuit 30 through the gas-side communication pipe 17.

  The refrigerant that has flowed into the indoor circuit 30 is introduced into the indoor heat exchanger 31. In the indoor heat exchanger 31, the refrigerant dissipates heat to the indoor air and condenses. That is, the refrigerant introduced into the indoor circuit 30 is condensed in the indoor heat exchanger 31, and as a result, the indoor air is heated.

  The refrigerant condensed in the indoor heat exchanger 31 flows into the outdoor circuit 20 through the liquid side communication pipe 16. Thereafter, the refrigerant is decompressed by the expansion valve 24 and then introduced into the outdoor heat exchanger 22.

  In the outdoor heat exchanger 22, the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the outdoor heat exchanger 22 passes through the four-way switching valve 21 and is sucked into the compressor 40 through the suction pipe 43. The compressor 40 compresses the sucked refrigerant and discharges it again. In the refrigerant circuit 10, such circulation of the refrigerant is repeated.

  The controller 91 of the controller 90 adjusts the opening degree of the expansion valve 24 as described above. At that time, the control unit 91 adjusts the opening degree of the expansion valve 24 so that the degree of superheat of the gas refrigerant flowing out of the outdoor heat exchanger 22 and sucked into the compressor 40 becomes constant. Specifically, the opening degree of the expansion valve 24 is appropriately changed so that the difference between the temperature detected by the intake refrigerant temperature sensor 73 and the temperature detected by the outdoor heat exchanger temperature sensor 76 is maintained at a predetermined value.

  Next, a first embodiment of a switching failure determination process (a switching failure determination method for a four-way switching valve) of the four-way switching valve 21 by the air conditioner 1 will be described. FIG. 4 is a flowchart showing the first embodiment of the switching failure determination process for the four-way switching valve 21 by the air conditioner 1. FIG. 5 is a diagram showing changes in the indoor heat exchanger temperature and the outdoor heat exchanger temperature after switching the four-way switching valve 21 from the port state for the heating operation to the port state for the cooling operation. ) Is a diagram illustrating a case where the four-way switching valve 21 is normally operated, and (b) is a diagram illustrating a case where the four-way switching valve 21 is malfunctioning. 6A shows a normal state of the slide valve 214 of the four-way switching valve 21 during the heating operation, and FIG. 6B shows a normal state of the slide valve 214 of the four-way switching valve 21 during the cooling operation. FIG. 4C is a diagram showing a malfunctioning state of the slide valve 214 of the four-way switching valve 21.

  The controller 91 switches the port of the four-way switching valve 21 to the four-way switching valve 21 in order to switch the port of the four-way switching valve 21 when the air-conditioning apparatus 1 is switched between cooling and heating operations or when switching from heating operation to defrost operation. When the signal is transmitted (YES in S1), the timer 921 of the switching failure determination unit 92 starts measuring the elapsed time from when the control unit 91 outputs the port switching signal to the four-way switching valve 21 (S2).

  The switching failure determination unit 92 starts sampling the temperature Th3 of the indoor heat exchanger 31 detected by the indoor heat exchanger temperature sensor 85 from the indoor heat exchanger temperature sensor 85 (S3), and the outdoor heat exchanger temperature sensor. From 76, sampling of the temperature Tm of the outdoor heat exchanger 22 detected by the outdoor heat exchanger temperature sensor 76 is started (S4).

  Further, when the timer 921 measures the elapse of a predetermined time (unit time) t, the switching failure determination unit 92 calculates the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 during the elapse time. At the same time (S5), the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm at the elapsed time is calculated (S6). This predetermined time t is assumed that the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm is reversed when the port of the four-way switching valve 21 is normally switched. It is the elapsed time from the time of the port switching signal output to the four-way switching valve 21 by the control unit 91 in FIG.

  In S5 and S6, the temperature sampled at the sampling start time is Th1, the predetermined time t is the predetermined time, and the temperature sampled after the predetermined time t has elapsed from the sampling start time is Th2. The defect determination unit 92 calculates the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 during the elapsed time and the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm during the elapsed time based on the following equations, respectively. .

Temperature change rate ΔTm, ΔTh3 = (Th1-Th2) / t
Then, the switching failure determination unit 92 determines whether or not the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is below a predetermined range Ta ₁ (first range), and whether the outdoor heat exchanger temperature Tm It is determined whether or not the temperature change rate ΔTm is outside a predetermined range Ta ₂ (second range) (S7).

The predetermined ranges Ta ₁ and Ta ₂ are as follows. For example, the operation of the air conditioner 1 is switched from the heating operation to the cooling operation, the four-way switching valve 21 operates normally, and the state shown in FIG. 6A (P1 and P3 are conductive, P2P4 is conductive) 6 (b) (P3 and P4 are conductive, P1 and P2 are conductive), and the inflow destination of the high-pressure refrigerant discharged from the compressor 40 is exchanged from the indoor heat exchanger 31 to the outdoor heat exchange. In the case of changing to the condenser 22, the indoor heat exchanger 31 is normally used as a condenser from the time when the indoor heat exchanger 31 functions as an evaporator with respect to the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3. A range above the reference temperature change rate α (assumed to be measured in advance based on the performance (compressor performance, refrigerant properties, pipe length, etc.) of each air conditioner 1) up to the time of functioning is a range Ta ₁ defined . For example, the predetermined range Ta ₁ used for the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is determined as the reference temperature change rate α ≦ Ta ₁ . In this case, the reference temperature change rate α is a temperature decrease rate.

On the other hand, for the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm, from the time when the outdoor heat exchanger 22 functions as a condenser to the time when the outdoor heat exchanger 22 functions normally as an evaporator. The range above the reference temperature change rate (assumed to be measured in advance based on the performance (compressor performance, refrigerant properties, pipe length, etc.) of each air conditioner 1) is the predetermined range Ta ₂ . For example, the predetermined range Ta ₂ used for the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is determined as the reference temperature change rate β ≦ Ta ₂ . In this case, the reference temperature change rate β is a temperature increase rate.

The predetermined ranges Ta ₁ and Ta ₂ are predetermined based on the reference temperature change rate measured according to the performance of each air conditioner 1 as described above, and stored in the switching failure determination unit 92. Yes. Therefore, for the predetermined ranges Ta ₁ and Ta ₂ , separately determined values are used according to the performances of the indoor heat exchanger 31 and the outdoor heat exchanger 22, for example.

Here, not switch properly determining unit 92, the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is is within the range Ta ₁ predetermined, and the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is determined in advance If it is determined that it is within the range Ta ₂ (NO in S7), the slide valve 214 of the four-way switching valve 21 operates normally based on the transmission of the port switching signal to the four-way switching valve 21. The compressor 40 operates normally and determines that the port has been switched correctly (S12), and the process ends.

On the other hand, not switch properly determining section 92, below out of range Ta ₁ in which the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is predetermined, and the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is determined in advance If it is determined that the value falls outside the range Ta ₂ (YES in S7), the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in S3 and S4 (Th3 during heating operation) > Tm, or Th3 <Tm at the time of cooling operation, at this time (the time after the passage of the predetermined period from the time when the port switching signal is output to the four-way switching valve 21 by the controller 91 in S1). It is determined whether the rotation is reversed (S8). The predetermined period is assumed to be that when the port of the four-way switching valve 21 is normally switched, the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm is reversed. Is the elapsed time from when the port switching signal is output to the four-way switching valve 21 by the controller 91.

  If the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in S3 and S4 is reversed after the predetermined period t has elapsed, the switching failure determination is made. If the unit 92 determines (YES in S8), the slide valve 214 of the four-way switching valve 21 operates normally based on the transmission of the port switching signal to the four-way switching valve 21, and the compressor 40 is normal. It is determined that the port has been correctly switched (S12), and the process ends.

For example, when the operation of the air conditioner 1 is switched from the heating operation to the cooling operation, the four-way switching valve 21 operates normally, and the state shown in FIG. 6A (P1 and P3 are conductive, P2P4 is conductive) ) To the state shown in FIG. 6B (P3 and P4 are conductive and P1 and P2 are conductive), the inflow destination of the high-pressure refrigerant discharged from the compressor 40 is changed from the indoor heat exchanger 31 to the outdoor. Instead of the heat exchanger 22, the indoor heat exchanger 31 that has been functioning as an evaporator until then functions as a condenser, and as shown in FIG. 5A, the reference temperature change rates α, β (or at least in advance) In the predetermined ranges Ta ₁ and Ta ₂ ), the indoor heat exchanger temperature Th3 decreases and the outdoor heat exchanger temperature Tm increases. Then, the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm are reversed.

However, as shown in FIG. 6C, when the amount of sliding movement by the slide valve 214 of the four-way switching valve 21 is insufficient and the port switching is poor, the port P1 of the four-way switching valve 21 is changed from the port P1 to the port P2. Since a part of the high-pressure refrigerant to be directed flows into the port P4, the high-pressure refrigerant cannot be sufficiently sent to the outdoor heat exchanger 22. Therefore, as shown in FIG. 5B, at the reference temperature change rates α and β (or at least the temperature change rates in the predetermined ranges Ta ₁ and Ta ₂ ) as planned, the indoor heat exchanger The temperature Th3 does not decrease, and the outdoor heat exchanger temperature Tm does not increase. Further, since the compression process by the compressor 40 is insufficient, heat exchange between the indoor heat exchanger 31 and the outdoor heat exchanger 22 is also insufficient, and the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm are reversed. do not do.

For this reason, after the control unit 91 outputs a switching instruction to the four-way switching valve 21, the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 and the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm are determined in advance. The state shown in FIG. 5 (b), which falls below the temperature change rate in the obtained ranges Ta ₁ and Ta ₂ , is detected, and further, the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm are detected not to be reversed. Thus, based on the detection result, the switching failure determination unit 92 can determine whether or not the port switching of the four-way switching valve 21 has been performed normally.

In addition, if the relationship between the indoor heat exchanger temperature Th3 at the beginning of sampling in S3 and S4 and the outdoor heat exchanger temperature Tm is not reversed after the predetermined period t has elapsed, the switching failure determination unit If 92 is determined (NO in S8), switching failure determination unit 92 further causes temperature change rate ΔTh3 of indoor heat exchanger temperature Th3 to fall below a predetermined range Tb ₁ (third range). Whether the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is outside the predetermined range Tb ₂ (fourth range) is determined (S9).

The predetermined range Tb ₁ is determined as the reference temperature change rate α ′ ≦ Tb _{1 in the same} manner as the above-described predetermined range Ta _{1. In} order to define the predetermined range Tb ₁ The reference temperature change rate α ′ used is a value smaller than the reference temperature change rate α used in the above-described predetermined range Ta ₁ . The predetermined range Tb ₁ is based on the rate of change in temperature when, for example, the compression operation becomes insufficient due to a decrease in the performance of the compressor 40 and the pressure of the high-pressure refrigerant discharged from the compressor 40 does not reach a predetermined value. Is a certain range. The predetermined range Tb ₁ is predetermined based on the performance (compressor performance, refrigerant properties, pipe length, etc.) of each air conditioner 1 and stored in the switching failure determination unit 92.

Also, the predetermined range Tb ₂ is determined as a reference temperature change rate β ′ ≦ Tb ₂ , similarly to the above-described predetermined range Ta _2, and defines the predetermined range Tb ₂ . Therefore, the reference temperature change rate β ′ used for the purpose is set to a value smaller than the reference temperature change rate β ′ used for the predetermined range Ta ₂ described above. The predetermined range Tb ₂ is based on the rate of change in temperature when, for example, the compression operation becomes insufficient due to a decrease in the performance of the compressor 40 and the pressure of the high-pressure refrigerant discharged from the compressor 40 does not reach the predetermined value. Is a certain range. The predetermined range Tb ₂ is predetermined based on the performance (compressor performance, refrigerant properties, pipe length, etc.) of each air conditioner 1, and is stored in the switching failure determination unit 92.

Here, not switch properly determining unit 92, the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is is within the range Tb ₁ of the predetermined and the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is determined in advance If it is determined that it is within the range Tb ₂ (NO in S9), the slide valve 214 operates normally based on the transmission of the port switching signal to the four-way switching valve 21, not the malfunction of the compressor 40. Otherwise, it is determined that the port switching of the four-way switching valve 21 is defective (S10).

Range Meanwhile, not switch properly determining section 92, below out of the range Tb ₁ in which the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is predetermined, that the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is predetermined If it is determined that the value is less than Tb ₂ (YES in S9), it is determined that the compressor 40 is not operating normally and not defective, and that the slide valve 214 of the four-way switching valve 21 is not operating normally. (S13).

  Thereafter, the control unit 91 notifies the notifying unit 94 that the port switching of the four-way switching valve 21 is defective or the compressor 40 is malfunctioning according to each determination result. (S11). For example, when the notification unit 94 includes a display unit such as an LCD (Liquid Crystal Display), the control unit 91 indicates that the port switching of the four-way switching valve 21 is defective or the compressor 40 is malfunctioning. A message indicating that there is a message is displayed on the display unit. When the notification unit 94 is composed of a buzzer or the like, the control unit 91 causes the buzzer to emit a warning sound or the like.

  In addition, when switching from the heating operation to the defrost operation, it is possible to determine the port switching failure of the four-way switching valve 21 and the operation failure of the compressor 40 in the same manner as described above. Further, when the air conditioner 1 is switched from the cooling operation to the heating operation, for example, consider the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm shown in FIGS. Thus, the port switching failure of the four-way switching valve 21 and the operation failure of the compressor 40 can be determined in the same manner as described above.

  In the present embodiment, the process of S9 and S13 is also performed to determine whether a port switching failure of the four-way switching valve 21 or a malfunction of the compressor 40 has occurred. Instead of determining the processing of S9 and S13, it may be determined whether the slide valve 214 of the four-way switching valve 21 operates normally and switches the port correctly.

  Next, a second embodiment of a switching failure determination process (a switching failure determination method for a four-way switching valve) of the four-way switching valve 21 by the air conditioner 1 will be described. FIG. 7 is a flowchart showing a second embodiment of the switching failure determination process for the four-way switching valve 21 by the air-conditioning apparatus 1. FIG. 8 is a diagram illustrating changes in the discharge refrigerant temperature and the intake refrigerant temperature of the compressor 40 after switching the four-way switching valve 21 from the port state during the heating operation to the port state during the cooling operation. ) Is a diagram illustrating a case where the four-way switching valve 21 is normally operated, and (b) is a diagram illustrating a case where the four-way switching valve 21 is malfunctioning.

The controller 91 switches the port of the four-way switching valve 21 to the four-way switching valve 21 in order to switch the port of the four-way switching valve 21 when the air-conditioning apparatus 1 is switched between cooling and heating operations or when switching from heating operation to defrost operation. When the signal is transmitted (YES in S21), the timer 921 of the switching failure determination unit 92 starts measuring the elapsed time from when the control unit 91 outputs the port switching signal to the four-way switching valve 21 (S22).

  The switching failure determination unit 92 starts sampling of the refrigerant temperature (intake temperature) Ts sucked into the compressor 40 detected by the intake refrigerant temperature sensor 73 from the intake refrigerant temperature sensor 73 (S23). Sampling of the temperature (discharge temperature) Td of the refrigerant discharged from the compressor 40 detected by the discharged refrigerant temperature sensor 75 is started from the sensor 75 (S24).

  Further, the switching failure determination unit 92 starts sampling the temperature Th3 of the indoor heat exchanger 31 from the indoor heat exchanger temperature sensor 85 (S25), and the temperature Tm of the outdoor heat exchanger 22 from the outdoor heat exchanger temperature sensor 76. Sampling is started (S26).

  When the timer 921 measures the elapse of a predetermined time, the switching failure determination unit 92 determines that the difference between the discharge temperature Td and the suction temperature Ts is less than the predetermined temperature difference T3. It is determined whether or not (S27).

  As in the case of the first embodiment, the predetermined period of time refers to the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm when the port of the four-way switching valve 21 is normally switched. Is the elapsed time from the time when the port switching signal is output to the four-way switching valve 21 by the control unit 91 in S21.

  Further, the predetermined temperature difference T3 is shown in FIG. 6A, for example, when the operation of the air conditioner 1 is switched from heating operation to cooling operation, the four-way switching valve 21 operates normally. The state (P1 and P3 are conducting, P2P4 is conducting) is switched to the state shown in FIG. 6B (P3 and P4 are conducting, P1 and P2 are conducting), and the high-pressure refrigerant discharged from the compressor 40 flows in. The temperature between the discharge temperature Td and the suction temperature Ts when the indoor heat exchanger 31 changes from the indoor heat exchanger 31 to the outdoor heat exchanger 22 and the indoor heat exchanger 31 that has previously functioned as an evaporator functions normally as a condenser. It is a difference. The temperature difference T <b> 3 is measured and determined in advance based on the performance (compressor performance, refrigerant properties, pipe length, etc.) of each air conditioner 1, and is stored in the switching failure determination unit 92.

  Here, if the switching failure determination unit 92 determines that the temperature difference between the discharge temperature Td and the suction temperature Ts is not less than the predetermined temperature difference T3 (NO in S27), the four-way switching is performed. Based on the transmission of the port switching signal to the valve 21, it is determined that the slide valve 214 of the four-way switching valve 21 operates normally and switches the port correctly (S12), and the process ends.

  On the other hand, when the switching failure determination unit 92 determines that the temperature difference between the discharge temperature Td and the suction temperature Ts is less than the predetermined temperature difference T3 (YES in S27), S25 and S26 are further performed. The relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in (at the time of heating operation Th3> Tm, or at the time of cooling operation Th3 <Tm) is determined at this time (four by the controller 91 in S21). It is determined whether or not the rotation is reversed after the port switching signal is output to the path switching valve 21 (at the time after the elapse of the predetermined period) (S28).

  Here, if the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in S25 and S26 is reversed after the predetermined period, the switching failure determination unit If YES is determined (YES in S28), it is determined that the slide valve 214 of the four-way switching valve 21 operates normally and switches the port correctly based on the transmission of the port switching signal to the four-way switching valve 21. (S12), and the process ends.

  On the other hand, if the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in S25 and S26 is not reversed after the predetermined period has elapsed, the switching failure determination unit 92 Is determined (NO in S28), the switching failure determination unit 92 determines that the slide valve 214 does not operate normally on the basis of the transmission of the port switching signal to the four-way switching valve 21 and the four-way switching valve 21. Is determined to be defective (S29).

  In this case, similarly to the first embodiment, the control unit 91 causes the notification unit 94 to perform notification indicating that the port switching of the four-way switching valve 21 is defective (S30).

  For example, when the operation of the air conditioner 1 is switched from the heating operation to the cooling operation, the four-way switching valve 21 operates normally, and the state shown in FIG. 6A (P1 and P3 are conductive, P2 and P4 Is switched to the state shown in FIG. 6B (P3 and P4 are conductive and P1 and P2 are conductive), the inflow destination of the high-pressure refrigerant discharged from the compressor 40 is the indoor heat exchanger 31. Is changed to the outdoor heat exchanger 22, and the indoor heat exchanger 31 that has been functioning as an evaporator until then functions as a condenser. As shown in FIG. 8A, the discharge is performed at a temperature difference T4 as planned. The temperature Td and the suction temperature Ts are settled. Then, the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm are reversed.

  However, as shown in FIG. 6C, when the amount of sliding movement by the slide valve 214 of the four-way switching valve 21 is insufficient and the port switching is poor, the port P1 of the four-way switching valve 21 is changed from the port P1 to the port P2. Since a part of the high-pressure refrigerant to be directed flows into the port P4, the high-pressure refrigerant cannot be sufficiently sent to the outdoor heat exchanger 22. For this reason, as shown in FIG. 8B, the discharge temperature Td and the suction temperature Ts are not settled at the expected temperature difference T4. Further, since the compression process by the compressor 40 is insufficient, heat exchange between the indoor heat exchanger 31 and the outdoor heat exchanger 22 is also insufficient, and the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm are reversed. do not do.

  For this reason, after the control unit 91 outputs a switching instruction to the four-way switching valve 21, the discharge temperature Td and the suction temperature Ts are in the state shown in FIG. By detecting a state in which the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm are not reversed, the switching failure determination unit 92 performs normal port switching of the four-way switching valve 21 based on the detection result. It is possible to determine whether or not it has been broken.

  Even when the heating operation is switched to the defrost operation, it is possible to determine the port switching failure of the four-way switching valve 21 as described above. When the air conditioner 1 is switched from the cooling operation to the heating operation, for example, consider the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm shown in FIGS. Thus, the port switching failure of the four-way switching valve 21 can be determined in the same manner as described above.

  Next, a third embodiment of the switching failure determination process for the four-way switching valve 21 by the air conditioner 1 will be described. FIG. 9 is a flowchart showing a third embodiment of the switching failure determination process for the four-way switching valve 21 by the air conditioner 1. Note that the description of the same processing as in the first or second embodiment is omitted.

  In the third embodiment, in addition to the processing of the first embodiment described above, it is further determined whether or not the difference between the discharge temperature Td and the suction temperature Ts used in the second embodiment is lower than the temperature difference T3. This is applied to the switching failure determination of the four-way switching valve 21.

  In the third embodiment, in order to switch the port of the four-way switching valve 21 at the time of switching the cooling / heating operation or switching from the heating operation to the defrost operation in the air conditioner 1, the control unit 91 When a port switching signal is transmitted to the path switching valve 21 (YES in S41), the same processes S42 to S46 as S2 to S6 shown in the first embodiment are executed.

  Thereafter, the switching failure determination unit 92 starts sampling the refrigerant temperature (suction temperature) Ts sucked into the compressor 40 detected by the suction refrigerant temperature sensor 73 from the suction refrigerant temperature sensor 73 (S47). Sampling of the temperature (discharge temperature) Td of the refrigerant discharged from the compressor 40 detected by the discharged refrigerant temperature sensor 75 is started from the discharged refrigerant temperature sensor 75 (S48).

Then, the switching failure determination unit 92 determines whether or not the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is below a predetermined range Ta ₁ (first range), and whether the outdoor heat exchanger temperature Tm It is determined whether or not the temperature change rate ΔTm is below a predetermined range Ta ₂ (second range) (S49), and the switching failure determination unit 92 determines that the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is When it is determined that the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is less than the predetermined range Ta ₁ and is lower than the predetermined range Ta ₂ (YES in S49), When the timer 921 measures the elapse of the predetermined time, the switching failure determination unit 92 reduces the difference between the discharge temperature Td and the suction temperature Ts below the predetermined temperature difference T3. Tsu determines whether or not that (S50).

  Here, when the switching failure determination unit 92 determines that the difference between the discharge temperature Td and the suction temperature Ts is lower than a predetermined temperature difference T3 (YES in S50), S33 and S34 are further performed. The relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in (the heating operation Th3> Tm or the cooling operation Th3 <Tm) is the four-way switching valve by the control unit 91 in S41. It is determined whether the rotation is reversed at the time after the elapse of the predetermined period from the time when the port switching signal is output to 21 (S51).

If the relationship between the indoor heat exchanger temperature Th3 and the outdoor heat exchanger temperature Tm at the beginning of sampling in S43 to S46 is not reversed after the predetermined period has elapsed, the switching failure determination unit When 92 is determined (NO in S51), switching failure determination unit 92 further causes temperature change rate ΔTh3 of indoor heat exchanger temperature Th3 to fall below a predetermined range Tb ₁ (third range). Whether or not the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is out of the predetermined range Tb ₂ (fourth range) is determined (S52).

Here, not switch properly determining unit 92, the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is is within the range Tb ₁ of the predetermined and the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is determined in advance If it is determined that it is within the range Tb ₂ (NO in S52), the slide valve 214 operates normally not based on the malfunction of the compressor 40 but based on the transmission of the port switching signal to the four-way switching valve 21. Otherwise, it is determined that the port switching of the four-way switching valve 21 is defective (S53).

Range Meanwhile, not switch properly determining section 92, below out of the range Tb ₁ in which the temperature change rate ΔTh3 of the indoor heat exchanger temperature Th3 is predetermined, that the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is predetermined If it is determined to be below out of the Tb ₂ (YES in S52), it is not malfunction of the slide valve 214 of the four-way switching valve 21, it is determined that the compressor 40 is caused a defect to not operate normally (S56).

  If NO in S49, NO in S50, and YES in S51, the slide valve 214 of the four-way switching valve 21 operates normally based on the transmission of the port switching signal to the four-way switching valve 21, and the compression is performed. The machine 40 operates normally and determines that the port has been switched correctly (S55), and ends the process.

  According to the third embodiment, in addition to the processing of the first embodiment described above, the difference between the discharge temperature Td and the suction temperature Ts used in the second embodiment is less than a predetermined temperature difference T3. Since the determination as to whether or not the four-way switching valve 21 is switched is determined to be accurate, the accuracy of the Po-switching failure determination of the four-way switching valve 21 is improved.

  Next, the pump down completion determination by the air conditioner 1 will be described. FIG. 10 is a flowchart showing pump down completion determination processing by the air conditioner 1. FIG. 11 is a block diagram illustrating a schematic configuration of a controller 90 ′ included in the air conditioner 1 that performs the pump down completion determination.

  The air conditioner 1 is a pump-down unit that recovers the refrigerant in the refrigerant circuit 10 to the outdoor unit 2 side based on an instruction from the operator when the outdoor unit 2 and the indoor unit 3 are removed from the installation location by the operator. Perform the action. The controller 90 ′ of the air conditioner 1 replaces the switching failure determination unit 92 in the configuration of the air conditioner 1 shown in FIG. 3 with a completion determination unit 95 that determines whether or not the pump-down operation is completed, A timer 951 built in the completion determination unit 95 is provided (FIG. 11).

  When pumping down, (1) the operator first closes the liquid side closing valve 25 of the outdoor unit 2 and (2) closes the gas side closing valve 26 of the outdoor unit 2 to near full closing.

  Thereafter, when an instruction for forced cooling operation is received by the input receiving unit 93 based on an operation by the operator (YES in S61), the control unit 91 controls driving of the compressor 40 and the like based on this instruction. The forced cooling operation is started (S62).

  Subsequently, the timer 951 of the completion determination unit 95 starts measuring the elapsed time from the start of the forced cooling operation by the control unit 91 (S63).

  The completion determination unit 95 starts sampling the temperature Tm of the outdoor heat exchanger 22 detected by the outdoor heat exchanger temperature sensor 76 (S64), and the indoor heat exchanger 31 detected by the indoor heat exchanger temperature sensor 85. The sampling of the temperature Th3 is started (S65).

  Further, when the elapsed time of a predetermined time is measured by the timer 951, the completion determination unit 95 calculates the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm during the elapsed time (S66).

  Then, the completion determination unit 95 determines whether or not the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm is lower than a predetermined temperature change rate T3 (S67). In S67, the completion determination unit 95 determines whether or not a predetermined time has elapsed since the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm has disappeared, instead of the determination. Also good.

  Here, the completion determination unit 95 determines that the temperature change rate ΔTm is lower than the temperature increase rate T3 (a predetermined time has elapsed since the temperature change rate ΔTm of the outdoor heat exchanger temperature Tm has disappeared). In this case (YES in S67), the completion determination unit 95 further returns to a temperature higher than the minimum value after the temperature Th3 of the indoor heat exchanger 31 once records the minimum value at this point, and It is determined whether the restored temperature Th3 is substantially equal to the indoor suction temperature Th4 detected by the outside air temperature sensor 71 (S68).

  After the temperature Th3 of the indoor heat exchanger 31 once records the minimum value, the completion determination unit 95 returns to a temperature higher than the minimum value, and the recovered temperature Th3 is substantially equal to the indoor suction temperature Th4. Is determined (YES in S68), it is determined that the pump-down is completed (S69). If NO in S67 and NO in S68, the process returns to S66.

  Then, the control part 91 makes the alerting | reporting part 94 alert | report that the pump down was completed (S70). For example, when the notification unit 94 includes a display unit such as an LCD (Liquid Crystal Display), the control unit 91 displays a message indicating that the pump-down is completed on the display unit. When the notification unit 94 is composed of a buzzer or the like, the control unit 91 causes the buzzer to emit a warning sound or the like.

  Conventionally, at the time of pump-down operation, the suction portion of the compressor 40 is close to a vacuum state. If the operation of the compressor 40 is continued in this state, depending on the design of the compressor 40, the suction portion may be loaded and compressed. There is a possibility that it may lead to malfunction of the machine 40. For this reason, the operator attaches a pressure sensor for measuring the refrigerant pressure to a service port (not shown) provided in the outdoor circuit 20 and the pressure measured by the pressure sensor becomes 0 MPa (0 kg / cm 2). In addition, it is necessary for the operator to determine completion of pump down based on the pressure value. However, in general, as the air conditioner closes to completion of the pump down, the amount of refrigerant circulating in the refrigerant circuit decreases, so the temperature rise in the outdoor heat exchanger gradually disappears, and the indoor heat exchanger Then, the indoor heat exchanger temperature decreases while the refrigerant is circulating in the refrigerant circuit, but the indoor heat exchanger is not cooled when there is no circulating refrigerant, so the indoor heat exchanger temperature is equal to the indoor suction temperature. It approaches the same. Based on this, the air conditioner 1 according to the present embodiment is such that the completion determination unit 95 is in a state where there is no temperature increase in the outdoor heat exchanger 22, and the heat exchanger temperature Th3 is equal to the indoor suction temperature Th4. Necessity of determination of completion of pump down by the operator based on the pressure sensor and the pressure value measured by the pressure sensor by determining that the pump down is completed with the detection when the approaching state is detected Can be eliminated.

  As mentioned above, although the air conditioning apparatus 1 which concerns on one Embodiment of this invention was demonstrated, the said embodiment is an illustration to the last, Comprising: This invention is not limited to the said embodiment, In the range which does not deviate from the meaning. Various changes and improvements can be made.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 3 Indoor unit 10 Refrigerant circuit 11 Liquid refrigerant pipe 12 Gas refrigerant pipe 16 Liquid side communication pipe 17 Gas side communication pipe 214 Slide valve 21 Four-way switching valve 22 Outdoor heat exchanger 30 Indoor circuit 31 Indoor heat Exchanger 40 Compressor 61 Liquid pipe temperature sensor 73 Intake refrigerant temperature sensor 75 Discharged refrigerant temperature sensor 76 Outdoor heat exchanger temperature sensor 85 Indoor heat exchanger temperature sensor 90 Controller 91 Control unit 92 Switching failure determination unit 93 Input reception unit 94 Notification Part 95 Completion determination part

Claims (4)

A refrigerant circuit in which an indoor heat exchanger (31), an outdoor heat exchanger (22), a compressor (40), a four-way switching valve (21), and an expansion valve (24) are connected by a refrigerant pipe ( 10) and
An indoor heat exchanger temperature detector (85) provided in the indoor heat exchanger (31) for detecting the temperature of the indoor heat exchanger (31);
An outdoor heat exchanger temperature detection unit (76) provided in the outdoor heat exchanger (22) for detecting the temperature of the outdoor heat exchanger (22);
A controller (91) for outputting a port switching signal to the four-way switching valve (21) and controlling port switching of the four-way switching valve (21);
After the port switching signal is output by the control unit (91), the temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detection unit (85) is within a predetermined first range. The temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) falls outside a predetermined second range, and The four-way switching valve when the temperature of the heat exchanger (31) and the temperature of the outdoor heat exchanger (22) satisfy a switching failure determination condition that they do not reverse within a predetermined period. An air conditioner comprising: a switching failure determination unit (92) that determines that the port switching failure is (21).   In the switching failure determination unit (92), the temperature change rate of the temperature of the indoor heat exchanger (31) detected by the indoor heat exchanger temperature detection unit (85) is more than the predetermined first range. Further, the temperature change rate of the temperature of the outdoor heat exchanger (22) detected by the outdoor heat exchanger temperature detection unit (76) is less than the third range determined based on the smaller temperature change rate, The temperature of the indoor heat exchanger (31) falls below a fourth range determined based on a temperature change rate that is smaller than the predetermined second range, and the outdoor heat exchange. The temperature of the compressor (22) is determined to be a malfunction of the compressor (40) when the switching failure determination condition that the temperature does not reverse within a predetermined period is satisfied. Air conditioner. Indoor heat exchanger (31), outdoor heat exchanger (22), compressor (40), four-way switching valve (21), indoor heat exchanger (31), and outdoor heat exchanger (22 And an expansion valve (24) provided between the refrigerant circuit (10) and the refrigerant pipe (24),
An indoor heat exchanger temperature detector (85) provided in the indoor heat exchanger (31) for detecting the temperature of the indoor heat exchanger (31);
An outdoor heat exchanger temperature detection unit (76) provided in the outdoor heat exchanger (22) for detecting the temperature of the outdoor heat exchanger (22);
A discharge temperature detection unit (75) that is provided on the discharge side of the compressor (40) in the refrigerant circuit (10) and detects the temperature of the refrigerant discharged from the compressor (40);
A suction temperature detection unit (73) provided on the suction side of the compressor (40) in the refrigerant circuit (10) for detecting the temperature of the refrigerant sucked into the compressor (40);
A control unit (91) for outputting a port switching signal to the drive unit of the four-way switching valve (21) and controlling the port switching of the four-way switching valve (21);
The temperature of the discharge refrigerant detected by the discharge temperature detection unit (75) and the temperature of the intake refrigerant detected by the suction temperature detection unit (73) after the port switching signal is output by the control unit (91). The difference is less than a predetermined temperature difference, and the temperature of the indoor heat exchanger (31) and the temperature of the outdoor heat exchanger (22) are not reversed within a predetermined period. An air conditioner including a switching failure determination unit (92) that determines that the port switching of the four-way switching valve (21) is defective. A discharge temperature detection unit (75) that is provided on the discharge side of the compressor (40) in the refrigerant circuit (10) and detects the temperature of the refrigerant discharged from the compressor (40);
A suction temperature detector (73) provided on the suction side of the compressor (40) in the refrigerant circuit (10) and detecting the temperature of the refrigerant sucked into the compressor (40);
The switching failure determination unit (92) satisfies the switching failure determination condition and outputs the temperature of the discharged refrigerant detected by the discharge temperature detection unit (75) after the port switching signal is output by the control unit (91). When the temperature difference with the temperature of the suction refrigerant detected by the suction temperature detection unit (73) is less than a predetermined temperature difference, it is determined that the port switching failure of the four-way switching valve (21). The air conditioning apparatus according to claim 1.

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