air conditioning

Abstract

An air conditioning system comprises a four-way valve with ports one through four, a first three-way valve and a second three-way valve, each with ports five through seven and a closed eighth port, a compressor, an interior heat exchanger, an expansion valve, a first exterior heat exchanger, a second exterior heat exchanger, a bypass expansion valve, a check valve, an outlet temperature sensor configured to measure the compressor outlet temperature, an interior duct temperature sensor configured to measure the duct temperature in the interior heat exchanger, an interior temperature sensor configured to measure the interior air temperature, a current sensor configured to measure a current supplied to the compressor, and a controller configured to detect a switching fault at the four-way valve.The first three-way valve and the second three-way valve are detected. The air conditioning system can operate in heating mode, defrosting mode, cooling mode, and simultaneous heating / defrosting mode. The controller is designed to detect a switching fault at the four-way valve, the first three-way valve, or the second three-way valve by using the temperatures and current measured by the outlet temperature sensor, the interior duct temperature sensor, and the interior temperature sensor, taking the operating status into account.

Description

Technical field

[0001] The present disclosure relates to an air conditioning system that can perform a heating operation, a defrosting operation and a simultaneous heating / defrosting operation. Underlying state of the art

[0002] Known air conditioning systems can perform heating and defrosting operations simultaneously (see, for example, JP 2012-13363A). JP 2012-13363A discloses an air conditioning system comprising a refrigerant circuit formed by connecting a compressor, a four-way valve, parallel-connected outdoor heat exchangers, pressure reducers located adjacent to the outdoor heat exchanger inlets, and an indoor heat exchanger via refrigerant lines. This refrigerant circuit can perform heating operation, reverse-cycle defrosting operation, and a defrost / heating operation in which some of the outdoor heat exchangers act as condensers and others as evaporators.

[0003] In this air conditioning system, the outdoor heat exchangers can be defrosted while heating continues simultaneously by performing a defrost / heating cycle. During defrost / heating, some of the refrigerant circuit's defrosting capacity is used for heating. This results in a longer time required to complete the defrosting process compared to a reverse-cycle defrosting cycle. In the air conditioning system disclosed in JP 2012-13363A, the defrost / heating cycle reduces the average heating capacity per cycle from the completion of one defrosting cycle until the completion of the next, during which heating occurs.

[0004] An air conditioning system was developed to improve average heating performance (see, for example, WO 2019 / 146 139 A1). WO 2019 / 146 139 A1 discloses an air conditioning system comprising a refrigerant circuit, two three-way valves, a check valve, and a bypass expansion valve. The refrigerant circuit includes a compressor, a four-way valve, a first outdoor heat exchanger, a second outdoor heat exchanger, and an indoor heat exchanger. In this air conditioning system, during heating operation, the two three-way valves switch between the two configurations such that either the first or the second outdoor heat exchanger operates as a condenser and the other outdoor heat exchanger as an evaporator, thus achieving simultaneous heating / defrosting operation.

[0005] In this air conditioning system, simultaneous heating / defrosting operation is performed when the difference between the compressor's maximum operating frequency and its operating frequency in heating mode is greater than or equal to a threshold value, and defrosting operation is performed when this difference is less than the threshold value. This increases the average heating output per cycle from the completion of one defrost cycle until the completion of the next, with heating operation occurring in between.

[0006] WO 2017 / 190 628 A1 discloses an air conditioning system designed to detect a malfunction of a four-way valve. The air conditioning system includes a detection device for detecting the temperature of an indoor heat exchanger, the temperature of the indoor environment, and a user-selected operating mode. Furthermore, the air conditioning system includes processing means for determining, based on the temperature of the indoor heat exchanger and the temperature of the indoor environment, whether the current operating mode of the air conditioning system is the same as the operating mode selected by the user.If the current operating mode differs from the operating mode set by the user, the four-way valve is determined to be in an abnormal communication state, and if the current operating mode is the same as the operating mode set by the user, the four-way valve is determined to be in a normal communication state. Brief description of the invention; Technical problem statement

[0007] In the air conditioning system disclosed in WO 2019 / 146 139 A1, for example, a switching error caused by a four-way valve or three-way valves, for whatever reason, creates a closed circuit in which no refrigerant circulates through the refrigerant circuit. This closed circuit can lead, for example, to an abnormally high pressure at the compressor or demagnetization as a result of a temperature increase in the compressor motor, causing compressor failure. Under such conditions, it is difficult to maintain the compressor's performance. Unfortunately, in conventional air conditioning systems, a switching error at a four-way or three-way valve cannot be detected.

[0008] In response to the above problem, one objective of the present disclosure is to specify an air conditioning system in which a switching error at a valve can be detected. Solution to the problem

[0009] An air conditioning system according to an embodiment of the present disclosure comprises the combination of the features of independent claim 1. Preferred further developments are found in the dependent claims. Advantageous effects of the invention

[0010] According to the embodiment of the present disclosure, a switching error at one of the valves can be detected, for example, by means of the temperatures measured by the outlet temperature sensor, the interior duct temperature sensor and the interior temperature sensor. Brief description of the characters Fig. Figure 1 shows a representation of a refrigerant circuit to illustrate a configuration example for an air conditioning system according to embodiment 1. Fig. Figure 2 shows a functional block diagram to illustrate a configuration example for a [system / device] in [a specific location]. Fig. 1 external control unit shown. Fig. Figure 3 shows a representation of a hardware configuration to illustrate a configuration example for a [system / device] in [a specific location / system]. Fig. 2 external controls shown. Fig. Figure 4 shows a representation of a hardware configuration to illustrate another configuration example for a [system / device] in [a specific context]. Fig. 2 external controls shown. Fig. Figure 5 shows a schematic representation to explain the refrigerant flow during heating operation of an air conditioning system according to embodiment 1. Fig. Figure 6 shows a schematic representation to explain the refrigerant flow during the defrosting operation of an air conditioning system according to embodiment 1. Fig. Figure 7 shows a schematic representation to explain the refrigerant flow during simultaneous heating / defrosting operation of an air conditioning system according to embodiment 1. Fig. Figure 8 shows the representation of a refrigerant circuit to illustrate a first example of the refrigerant flow in an air conditioning system according to embodiment 1 under the condition of a valve switching error when switching between operating modes. Fig. Figure 9 shows the representation of a refrigerant circuit to illustrate a second example of the refrigerant flow in an air conditioning system according to embodiment 1 under the condition of a valve switching error when switching between operating modes. Fig. Figure 10 shows a flowchart illustrating an example of a method for detecting switching errors of the four-way valve in an air conditioning system according to embodiment 1. Fig. Figure 11 shows a flowchart illustrating an example of a method for detecting switching errors of a three-way valve in an air conditioning system according to embodiment 1. Fig. Figure 12 shows a representation of a refrigerant circuit to illustrate a configuration example for an air conditioning system according to embodiment 2. Fig. Figure 13 shows a functional block diagram to illustrate a configuration example for a Fig. 12 external controls shown. Fig. Figure 14 shows a flowchart illustrating an example of a four-way valve switching fault detection method in an air conditioning system according to embodiment 2. Fig. Figure 15 shows a flowchart illustrating an example of a three-way valve switching fault detection method in an air conditioning system according to embodiment 2. Description of embodiments

[0011] Embodiments of the present disclosure are described with reference to the figures. The following embodiments are not to be understood as limiting the present disclosure and can be modified in various ways without departing from the core and scope of the present disclosure. Furthermore, the present disclosure includes any and all combinations of components that can be combined in the following embodiments. It is also noted that the components designated with the same reference numerals in the following figures are the same or equivalent components. This note applies to the entire present description. Design 1

[0012] An air conditioning system according to embodiment 1 is described. The air conditioning system according to embodiment 1 is designed to perform at least one heating operation, one cooling operation, one reverse cycle defrosting operation (hereinafter referred to as "defrosting operation" for simplicity), and one simultaneous heating / defrosting operation. [Air conditioning configuration 100]

[0013] Fig. Figure 1 shows a representation of a refrigerant circuit to illustrate a configuration example for an air conditioning system according to embodiment 1. As in Fig. As shown in Figure 1, the air conditioning system 100 according to embodiment 1 comprises a refrigerant circuit 10 through which refrigerant circulates, an outdoor (room) control unit 50, and an indoor control unit 60. The control units regulate the refrigerant circuit 10. A compressor 11, a four-way valve 12, an indoor heat exchanger 13, an expansion valve 14, a first outdoor (room) heat exchanger 15a, a second outdoor (room) heat exchanger 15b, a first three-way valve 16a, a second three-way valve 16b, capillary tubes 17a and 17b, a bypass expansion valve 18, and a check valve 19 are interconnected by refrigerant lines, with the refrigerant flowing through these components. In this way, the refrigerant circuit 10 is formed.

[0014] The air conditioning system 100 also comprises an outdoor unit, which is mounted outside a room, and an indoor unit, which is mounted inside a room. The outdoor unit contains the compressor 11, the four-way valve 12, the expansion valve 14, the first outdoor heat exchanger 15a, the second outdoor heat exchanger 15b, the first three-way valve 16a, the second three-way valve 16b, the capillary tubes 17a and 17b, the bypass expansion valve 18, and the check valve 19. The indoor unit contains the indoor heat exchanger 13. (Compressor 11)

[0015] Compressor 11 draws in gaseous low-pressure refrigerant, compresses it into gaseous high-pressure refrigerant, and discharges the refrigerant. For example, an inverter-driven compressor with an adjustable operating frequency is used as compressor 11. An operating frequency range is preset for compressor 11. Compressor 11 is designed to operate under the control of the external controller 50 at a variable operating frequency within this range. (Four-way valve 12)

[0016] The four-way valve 12, which reverses the flow direction of the refrigerant in the refrigerant circuit 10, has four ports: E, F, G, and H. In the following description, port G, port E, port F, and port H will be referred to as "first port G," "second port E," "third port F," and "fourth port H," respectively. The four-way valve 12 can assume a first position in which the second port E is connected to the third port F and the first port G is connected to the fourth port H, and a second position in which the second port E is connected to the fourth port H and the third port F is connected to the first port G. Under the control of the external controller 50, the four-way valve 12 is moved to the first position during heating operation and simultaneous heating / defrosting operation, and to the second position during defrosting operation and cooling operation. (Interior heat exchanger 13)

[0017] The interior heat exchanger 13 exchanges heat between the refrigerant flowing through it and the interior air, which is supplied by an interior fan (not shown) housed within the interior heat exchanger. In heating mode, the interior heat exchanger 13 acts as a condenser, transferring heat from the refrigerant to the interior air to condense the refrigerant and warm the interior air. In cooling mode, the interior heat exchanger 13 acts as an evaporator, vaporizing the refrigerant to cool the interior air using the heat of vaporization. (Expansion valve 14)

[0018] The expansion valve 14 is a valve that reduces the pressure of the refrigerant. For example, an electronic expansion valve is used as expansion valve 14, the opening degree of which is adjustable under the control of the external control unit 50. The opening degree of the expansion valve 14 is controlled by the external control unit 50. (First outdoor (room) heat exchanger 15a and second outdoor (room) heat exchanger 15b)

[0019] The first external heat exchanger 15a and the second external heat exchanger 15b each exchange heat between the refrigerant flowing through them and the outside (room) air, which is supplied by an external fan (not shown) housed in the external heat exchanger. The first external heat exchanger 15a and the second external heat exchanger 15b operate as evaporators in heating mode and as condensers in cooling mode.

[0020] The first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b are connected in parallel to each other in the refrigerant circuit 10. The first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b are formed, for example, by dividing a single heat exchanger into an upper and a lower part. In this case, the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b are arranged parallel to each other in the direction of airflow. (First three-way valve 16a and second three-way valve 16b)

[0021] The first three-way valve 16a and the second three-way valve 16b each switch between the refrigerant flow directions for heating, defrosting, and cooling operation, as well as for simultaneous heating / defrosting operation. The first three-way valve 16a, for example, is a four-way valve with four ports Aa, Ba, Ca, and Da, where port Ba is closed to prevent refrigerant leakage. In the following description, port Ca, port Aa, port Da, and port Ba can be referred to as "fifth port Ca," "sixth port Aa," "seventh port Da," and "eighth port Ba," respectively.

[0022] The second three-way valve 16b, for example, is a four-way valve with four ports Ab, Bb, Cb, and Db, where port Bb is closed to prevent refrigerant leakage. In the following description, port Cb, port Ab, port Db, and port Bb can be referred to as "fifth port Cb," "sixth port Ab," "seventh port Db," and "eighth port Bb," respectively.

[0023] The first three-way valve 16a and the second three-way valve 16b can assume a first position, a second position, a third position, and a fourth position. In the first position of the first three-way valve 16a, the sixth port Aa is connected to the seventh port Da, and the eighth port Ba is connected to the fifth port Ca. In the first position of the second three-way valve 16b, the sixth port Ab is connected to the seventh port Db, and the eighth port Bb is connected to the fifth port Cb. In the second position of the first three-way valve 16a, the sixth port Aa is connected to the eighth port Ba, and the fifth port Ca is connected to the seventh port Da. In the second position of the second three-way valve 16b, the sixth port Ab is connected to the eighth port Bb, and the fifth port Cb is connected to the seventh port Db.

[0024] In the third position of the first three-way valve 16a, the sixth port Aa is connected to the eighth port Ba, and the fifth port Ca is connected to the seventh port Da. In the third position of the second three-way valve 16b, the sixth port Ab is connected to the seventh port Db, and the eighth port Bb is connected to the fifth port Cb. In the fourth position of the first three-way valve 16a, the sixth port Aa is connected to the seventh port Da, and the eighth port Ba is connected to the fifth port Ca. In the fourth position of the second three-way valve 16b, the sixth port Ab is connected to the eighth port Bb, and the fifth port Cb is connected to the seventh port Db.

[0025] Under the control of the external control unit 50, the first three-way valve 16a and the second three-way valve 16b are set to the first position during heating operation and to the second position during defrosting and cooling operation. Under the control of the external control unit 50, the first three-way valve 16a and the second three-way valve 16b are moved to the third or fourth position during simultaneous heating / defrosting operation. (Capillary tubes 17a and 17b)

[0026] The capillary tubes 17a and 17b reduce the refrigerant pressure. Capillary tube 17a is located between the first outdoor heat exchanger 15a and the expansion valve 14. Capillary tube 17b is located between the second outdoor heat exchanger 15b and the expansion valve 14. (Bypass expansion valve 18)

[0027] The bypass expansion valve 18 is located between the compressor outlet 11 and the two three-way valves, specifically the first three-way valve 16a and the second three-way valve 16b. The bypass expansion valve 18 adjusts the refrigerant flow rate while either the first outdoor heat exchanger 15a or the second outdoor heat exchanger 15b is being defrosted during simultaneous heating / defrosting operation. The bypass expansion valve 18 is opened or closed under the control of the outdoor control unit 50. An electronic expansion valve is used as the bypass expansion valve 18. However, the bypass expansion valve 18 can also be any other type of valve, such as a solenoid valve or a motor-driven valve. The bypass expansion valve 18 also reduces the refrigerant pressure. (Check valve 19)

[0028] The check valve 19 is arranged between the downstream side of the bypass expansion valve 18 and port F of the four-way valve 12. The check valve 19 controls the refrigerant flow direction so that gaseous high-pressure refrigerant discharged from the compressor 11 does not flow back to the compressor 11 via the four-way valve 12 during heating operation or simultaneous heating / defrosting operation. Specifically, the check valve 19 is designed to allow refrigerant flow from port F of the four-way valve 12 to the first three-way valve 16a and the second three-way valve 16b, while blocking refrigerant flow from the downstream side of the bypass expansion valve 18 to port F of the four-way valve 12. (Sensors)

[0029] The air conditioning system 100 further comprises an outlet temperature sensor 31, an interior duct temperature sensor 32, an interior temperature sensor 33, and a current sensor 34. The outlet temperature sensor 31 is located on the refrigerant line between the compressor 11 and the four-way valve 12 or on the surface of the compressor's outlet area. The outlet temperature sensor 31 measures the temperature of the gaseous high-temperature refrigerant discharged by the compressor 11. The interior duct temperature sensor 32 is located on the refrigerant line in the interior heat exchanger 13. The interior duct temperature sensor 32 measures the duct temperature, or the temperature of the duct through which the refrigerant flows in the interior heat exchanger 13. In the following description, the duct temperature in the interior heat exchanger 13 may be referred to as the "interior duct temperature".

[0030] The interior temperature sensor 33 is located inside the interior unit. The interior temperature sensor 33 measures the temperature of the interior air. The current sensor 34 is located on the compressor 11. The current sensor 34 measures the current supplied to the compressor 11 during operation. (Interior control 60)

[0031] The indoor control unit 60 receives information from these sensors about the temperatures measured by the indoor air temperature sensor 32 and the indoor air temperature sensor 33. Furthermore, the indoor control unit 60 receives various individual pieces of information, such as operating and setting information, which are entered by user operations, e.g., via a remote control (not shown). The indoor control unit 60 transmits the various individual pieces of information received to the outdoor control unit 50. The indoor control unit 60 is configured, for example, as an arithmetic unit, such as a microcomputer on which software for implementing a variety of functions is executed, or as hardware, such as circuit devices that correspond to the functions. (External (room) control 50)

[0032] The external control unit 50 receives various individual pieces of information, such as temperature information, from the internal control unit 60. The external control unit 50 also receives information about the temperature measured by the outlet temperature sensor 31. Furthermore, the external control unit 50 receives information about the current flowing to the compressor 11, which is measured by the current sensor 34. Based on the various individual pieces of information received, the external control unit 50 controls the components of the refrigerant circuit 10, which includes the compressor 11, the four-way valve 12, the expansion valve 14, the first three-way valve 16a, the second three-way valve 16b, the bypass expansion valve 18, and the internal and external blowers (not shown).

[0033] Fig. Figure 2 shows a functional block diagram to illustrate a configuration example for a [system / device] in [a specific location]. Fig. 1. External control shown. As in Fig. As shown in Figure 2, the external control unit 50 comprises an information acquisition unit 51, an operating status determination unit 52, a temperature difference calculation unit 53, a comparison unit 54, and a storage unit 55. The external control unit 50 is configured, for example, as an arithmetic unit, such as a microcomputer running software to implement a variety of functions, or as hardware, such as circuit devices corresponding to the functions. Fig. Figure 2 shows components for the functions relating to embodiment 1, with the representation of the other components omitted.

[0034] The information acquisition unit 51 receives various individual pieces of information, such as information about measurements from the sensors in the air conditioning system 100 and operating information entered by a user. According to embodiment 1, the information acquisition unit 51 receives the outlet temperature or the temperature of the refrigerant discharged by the compressor 11 from the outlet temperature sensor 31. The information acquisition unit 51 receives the interior duct temperature, measured by the interior duct temperature sensor 32, via the interior control unit 60. The information acquisition unit 51 receives the interior temperature measured by the interior temperature sensor 33 via the interior control unit 60. The information acquisition unit 51 receives a current value I of the current supplied to the compressor 11 from the current sensor 34.Furthermore, the information acquisition unit 51 receives operating information about the air conditioning system 100 via the interior control unit 60, which is set, for example, by a user using a remote control (not shown).

[0035] The operating status determination unit 52 determines the operating status of the air conditioning system 100 based on the operating information received from the information acquisition unit 51.

[0036] The temperature difference calculation unit 53 calculates a temperature difference, which is the difference between two individual temperature values, based on the indoor temperature, the indoor duct temperature, and the outlet temperature, which are obtained from the information acquisition unit 51. According to embodiment 1, the temperature difference calculation unit 53 calculates the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature. Furthermore, the temperature difference calculation unit 53 calculates the temperature difference ΔT2 between the outlet temperature and the indoor duct temperature.

[0037] The comparison unit 54 compares various individual pieces of information. According to embodiment 1, the comparison unit 54 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 53 with a first temperature difference threshold T. th1, which is stored in storage unit 55. The first temperature difference threshold T th1 is a predefined value for the temperature difference ΔT1. Furthermore, the comparison unit 54 compares the temperature difference ΔT2 calculated by the temperature difference calculation unit 53 with a second temperature difference threshold value T. th2 , which is stored in storage unit 55. The second temperature difference threshold T th2 is a predefined value for the temperature difference ΔT2. The first temperature difference threshold T th1 and the second temperature difference threshold T th2 are used to determine whether the four-way valve 12, the first three-way valve 16a and the second three-way valve 16b are switched normally.

[0038] Furthermore, the comparison unit 54 compares the current value I of the current supplied to the compressor 11, which was obtained from the information acquisition unit 51, with a current threshold value I. th , which is stored in storage unit 55. The current threshold I th is a specified value for the current value I, which is used to determine whether compressor 11 is likely to be operating under abnormal conditions.

[0039] The storage unit 55 stores various values ​​that are to be used in the units of the external control 50. According to embodiment 1, the storage unit 55 stores the first temperature difference threshold value T. th1 , the second temperature difference threshold T th2 and the current threshold I th , which are used by the comparison unit 54.

[0040] Fig. Figure 3 shows a representation of a hardware configuration to illustrate a configuration example for a [system / device] in [a specific location / system]. Fig. 2. External control unit 50 shown. If the various functions of the external control unit 50 are executed by hardware, the external control unit 50 exhibits the following characteristics: Fig. 2 a processing circuit 71 as in Fig. 3 is shown. With the external control 50 of Fig. 2 the processing circuit 71 implements the functions of the information acquisition unit 51, the operating status determination unit 52, the temperature difference calculation unit 53, the comparison unit 54 and the storage unit 55.

[0041] When the functions are performed by hardware, the processing circuit 71 corresponds, for example, to a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof. In the case of the external control unit 50, the functions of the information acquisition unit 51, the operating status determination unit 52, the temperature difference calculation unit 53, the comparison unit 54, and the storage unit 55 can be implemented by individual processing circuits 71. The functions of the units can also be implemented by a single processing circuit 71.

[0042] Fig. Figure 4 shows a representation of a hardware configuration to illustrate another configuration example for a [system / device]. Fig. 2. External control unit 50 shown. If the various functions of the external control unit 50 are executed by software, the external control unit 50 comprises: Fig. 2 a processor 81 and a memory 82, as in Fig. Figure 4 is shown. In the external control unit 50, the processor 81 and the memory 82 implement the functions of the information acquisition unit 51, the operating status determination unit 52, the temperature difference calculation unit 53, the comparison unit 54 and the storage unit 55.

[0043] When the functions are executed by software, the functions of the information acquisition unit 51, the operating status determination unit 52, the temperature difference calculation unit 53, the comparison unit 54, and the storage unit 55 in the external control unit 50 are implemented by software, firmware, or a combination of software and firmware. Software and firmware are described as programs and are stored in memory 82. The processor 81 reads the programs stored in memory 82 and executes them, thereby implementing the functions.

[0044] Examples of Memory 82 include non-volatile and volatile semiconductor memories, such as random-access memory (RAM), read-only memory (ROM), flash memory, erasable programmable ROM (EPROM), and electrically erasable programmable ROM (EEPROM). Removable recording media, such as a magnetic disk, floppy disk, optical disc, compact disc (CD), miniDisc (MD), or digital versatile disc (DVD), can also be used as Memory 82. [Functions of an air conditioner 100]

[0045] The functions of an air conditioner 100 with the configuration described above will now be described. The functions of the air conditioner 100 in heating mode, defrosting mode, and simultaneous heating / defrosting mode are described below. The functions of the air conditioner 100 in cooling mode are the same as those in defrosting mode, and their description is therefore omitted. (Heating operation)

[0046] The operation of the air conditioner 100 in heating mode will now be described. Heating mode is a mode in which the refrigerant flows through the refrigerant circuit 10 to heat the room air. Fig. Figure 5 shows a schematic representation to illustrate the refrigerant flow during heating operation of an air conditioning system according to embodiment 1. Fig. In Figure 5, the bold lines represent the refrigerant flow paths, with the arrows indicating the refrigerant flow direction. The refrigerant flow paths and refrigerant flow direction are shown in the... Fig. 6 and Fig. The 7 items described later are presented in the same way.

[0047] As in Fig. As shown in Figure 5, the four-way valve 12 is in its first position during heating operation, in which the first port G is connected to the fourth port H and the second port E to the third port F. The first three-way valve 16a and the second three-way valve 16b are also in their first positions. In the first three-way valve 16a, the sixth port Aa is connected to the seventh port Da and the fifth port Ca is connected to the eighth port Ba. In the second three-way valve 16b, the sixth port Ab is connected to the seventh port Db and the fifth port Cb is connected to the eighth port Bb. The bypass expansion valve 18 is, for example, but not necessarily, set to an open position. The bypass expansion valve 18 can also be set to a closed position.

[0048] The gaseous high-pressure refrigerant exiting compressor 11 flows through the four-way valve 12 into the interior heat exchanger 13. During heating operation, the interior heat exchanger 13 functions as a condenser. Specifically, the refrigerant flowing through the interior heat exchanger 13 exchanges heat with the interior air supplied by the interior fan (not shown), thus transferring the refrigerant's latent heat of condensation to the interior air. Upon entering the interior heat exchanger 13, the gaseous refrigerant condenses into liquid high-pressure refrigerant. The interior air supplied by the interior fan is heated by the heat transferred from the refrigerant.

[0049] The liquid refrigerant exiting the interior heat exchanger 13 flows into the expansion valve 14. The pressure of the refrigerant is reduced by the expansion valve 14, creating a two-phase, low-pressure refrigerant. The two-phase refrigerant exiting the expansion valve 14 is split into two streams. One stream of the two-phase refrigerant undergoes further pressure reduction through the capillary tube 17a and then enters the first exterior heat exchanger 15a. The other stream of the two-phase refrigerant undergoes further pressure reduction through the capillary tube 17b and then enters the second exterior heat exchanger 15b.

[0050] In heating mode, the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b each operate as evaporators. Specifically, the refrigerant flowing through the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b exchanges heat with the outside air supplied by the outdoor fan (not shown) and receives heat of vaporization from the outside air. In this way, the two-phase refrigerant flowing through the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b evaporates into a gaseous, low-pressure refrigerant.

[0051] The two streams of gaseous refrigerant exiting the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b flow through the first three-way valve 16a and the second three-way valve 16b, respectively, and then merge. The refrigerant is then drawn into the compressor 11. In the compressor 11, the drawn-in gaseous refrigerant is compressed into high-pressure gaseous refrigerant. During heating operation, the cycle described above is repeated continuously.

[0052] Such heating operation, if continued over a longer period, can cause the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b to ice up, leading to a reduction in the heat transfer efficiency of the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b. For this reason, the air conditioning system 100 according to embodiment 1 periodically performs a defrosting operation or a simultaneous heating / defrosting operation to melt frost on the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b. (Defrosting operation)

[0053] The following describes the operation of the air conditioning system 100 during defrosting. Defrosting is a process for removing frost from the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b. Fig. Figure 6 shows a schematic representation to explain the refrigerant flow during the defrosting operation of an air conditioning system according to embodiment 1.

[0054] As in Fig. As shown in Figure 6, the four-way valve 12 is in the second position during defrosting, in which the first port G is connected to the third port F and the second port E to the fourth port H. The first three-way valve 16a and the second three-way valve 16b are also in the second position. In the first three-way valve 16a, the sixth port Aa is connected to the eighth port Ba and the fifth port Ca to the seventh port Da. In the second three-way valve 16b, the sixth port Ab is connected to the eighth port Bb and the fifth port Cb to the seventh port Db. The bypass expansion valve 18 is, for example, set to the open position.

[0055] The high-pressure gaseous refrigerant exiting compressor 11 is split into two streams, one flowing towards bypass expansion valve 18 and the other towards four-way valve 12. The gaseous refrigerant exiting four-way valve 12 flows through check valve 19 and then merges on the downstream side of bypass expansion valve 18 with the gaseous refrigerant exiting the bypass expansion valve 18. After merging on the downstream side of bypass expansion valve 18, the gaseous refrigerant is split into two streams, one flowing in a first direction towards the first three-way valve 16a and the other flowing in a second direction towards the second three-way valve 16b.

[0056] The gaseous refrigerant flowing in the first direction passes through the first three-way valve 16a and then enters the first outdoor heat exchanger 15a. The gaseous refrigerant flowing in the second direction passes through the second three-way valve 16b and then enters the second outdoor heat exchanger 15b. During defrosting, the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b each function as a condenser. Specifically, the refrigerant flowing through the first outdoor heat exchanger 15a and the second outdoor heat exchanger 15b transfers heat to melt the frost on the first and second outdoor heat exchangers 15a and 15b. This defrosts the first and second outdoor heat exchangers 15a and 15b. The gaseous refrigerant then condenses into liquid refrigerant in the first and second outdoor heat exchangers 15b.

[0057] The liquid refrigerant exiting the first outdoor heat exchanger 15a is pressure-reduced by the capillary tube 17a. The liquid refrigerant exiting the second outdoor heat exchanger 15b is pressure-reduced by the capillary tube 17b. The liquid refrigerant, pressure-reduced by capillary tube 17a, merges with the liquid refrigerant, pressure-reduced by capillary tube 17b. The refrigerant then flows into the expansion valve 14. In the expansion valve 14, the pressure of the liquid refrigerant is further reduced, forming a two-phase, low-pressure refrigerant. The two-phase refrigerant exiting the expansion valve 14 flows into the indoor heat exchanger 13. During defrosting operation, the indoor heat exchanger 13 functions as an evaporator. Specifically, the refrigerant flowing through the indoor heat exchanger 13 extracts heat of vaporization from the room air.In the interior heat exchanger 13, the two-phase refrigerant evaporates into a gaseous low-pressure refrigerant.

[0058] The gaseous refrigerant exiting the interior heat exchanger 13 flows through the four-way valve 12 and is drawn into the compressor 11. The compressor 11 compresses the drawn-in gaseous refrigerant into high-pressure gaseous refrigerant. During defrosting operation, the cycle described above is repeated continuously. Since, as described above, both the first exterior heat exchanger 15a and the second exterior heat exchanger 15b are supplied with high-temperature, high-pressure gaseous refrigerant during defrosting operation, both the first exterior heat exchanger 15a and the second exterior heat exchanger 15b are defrosted by the heat transferred by the refrigerant. (Simultaneous heating / defrosting operation)

[0059] The following describes the operation of the air conditioning unit 100 in simultaneous heating / defrosting mode. Simultaneous heating / defrosting mode is an operation in which defrosting is carried out on the first outdoor heat exchanger 15a or the second outdoor heat exchanger 15b, and heating is carried out simultaneously using the other of the two outdoor heat exchangers. Fig. Figure 7 shows a schematic representation to explain the refrigerant flow during simultaneous heating / defrosting operation of an air conditioning system according to embodiment 1.

[0060] The simultaneous heating / defrosting operation comprises a first and a second process. In the first process, the first outdoor heat exchanger 15a and the indoor heat exchanger 13 operate as condensers, and the second outdoor heat exchanger 15b operates as an evaporator. This defrosts the first outdoor heat exchanger 15a, and heating continues. In the second process, the second outdoor heat exchanger 15b and the indoor heat exchanger 13 operate as condensers, and the first outdoor heat exchanger 15a operates as an evaporator. This defrosts the second outdoor heat exchanger 15b, and heating continues. Fig. Figure 7 illustrates the operation during the first process of simultaneous heating / defrosting operation.

[0061] As in Fig. As shown in Figure 7, the four-way valve 12 is in the first position during simultaneous heating / defrosting operation. In this position, the first port G is connected to the fourth port H, and the second port E is connected to the third port F. The first three-way valve 16a and the second three-way valve 16b are set to the third position. In the first three-way valve 16a, the sixth port Aa is connected to the eighth port Ba, and the fifth port Ca is connected to the seventh port Da. In the second three-way valve 16b, the sixth port Ab is connected to the seventh port Db, and the fifth port Cb is connected to the eighth port Bb. The bypass expansion valve 18 is set to the open position at a predetermined degree of opening.

[0062] A portion of the high-pressure gaseous refrigerant delivered by compressor 11 enters the bypass expansion valve 18. After entering the bypass expansion valve 18, the pressure of the gaseous refrigerant is reduced. The refrigerant flows through the first three-way valve 16a and then into the first outdoor heat exchanger 15a. In the first outdoor heat exchanger 15a, the refrigerant transfers heat to melt the frost on the heat exchanger, thus defrosting the first outdoor heat exchanger 15a. The gaseous refrigerant then condenses into liquid high-pressure refrigerant or two-phase refrigerant in the first outdoor heat exchanger 15a. The refrigerant then flows out of the first outdoor heat exchanger 15a. The pressure of the refrigerant is reduced by the capillary tube 17a.

[0063] The remaining portion of the gaseous high-pressure refrigerant discharged by compressor 11 flows through the four-way valve 12 and enters the interior heat exchanger 13. In the interior heat exchanger 13, heat exchange takes place between the refrigerant flowing through it and the room air supplied by the interior fan (not shown). The refrigerant's latent heat of condensation is transferred to the room air. In this way, the gaseous refrigerant condenses into liquid high-pressure refrigerant in the interior heat exchanger 13. The room air supplied by the interior fan is heated by the heat transferred by the refrigerant.

[0064] The liquid refrigerant leaves the interior heat exchanger 13 and enters the expansion valve 14. In the expansion valve 14, the pressure of the liquid refrigerant is reduced, forming a two-phase, low-pressure refrigerant. The two-phase refrigerant flowing from the expansion valve 14 combines with the liquid refrigerant or the two-phase refrigerant whose pressure has been reduced by the capillary tube 17a. The refrigerant is further pressure-reduced by the capillary tube 17b and then flows into the second exterior heat exchanger 15b. In the second exterior heat exchanger 15b, the refrigerant exchanges heat with the outside air supplied by the outside fan (not shown) and absorbs heat of vaporization from the outside air. In the second exterior heat exchanger 15b, the two-phase refrigerant evaporates to a gaseous, low-pressure refrigerant.

[0065] The gaseous refrigerant exiting the second external heat exchanger 15b flows through the second three-way valve 16b and is then drawn into the compressor 11. The drawn-in gaseous refrigerant is compressed by the compressor 11 into high-pressure gaseous refrigerant. During the first operation of the simultaneous heating / defrosting cycle, the cycle described above is continuously repeated to defrost the first external heat exchanger 15a and continue heating.

[0066] Although not shown, the four-way valve 12 is set to the first position in the second simultaneous heating / defrosting operation, similar to the first operation. The first three-way valve 16a and the second three-way valve 16b are set to the fourth position. In the first three-way valve 16a, the sixth port Aa is connected to the seventh port Da, and the fifth port Ca is connected to the eighth port Ba. In the second three-way valve 16b, the sixth port Ab is connected to the eighth port Bb, and the fifth port Cb is connected to the seventh port Db. The bypass expansion valve 18 is set to the open position at a predetermined opening degree, similar to the first operation. Thus, in the second operation, the second outdoor heat exchanger 15b is defrosted while heating continues.

[0067] As described above, during simultaneous heating / defrosting operation, one of the two outdoor heat exchangers 15a and 15b is supplied with gaseous high-temperature / high-pressure refrigerant. The other of the two outdoor heat exchangers 15a and 15b functions as an evaporator. This allows heating to continue with the other outdoor heat exchanger while one of the outdoor heat exchangers is defrosting during simultaneous heating / defrosting operation. [Error switching valves]

[0068] Valve switching errors in an air conditioning system 100 according to embodiment 1 are now described. In the air conditioning system 100 according to embodiment 1, when switching between operating modes, e.g., from cooling to heating mode, a valve, such as the four-way valve 12, the first three-way valve 16a, or the second three-way valve 16b, may fail to switch normally for some reason. Under such conditions, the refrigerant cannot flow normally through the refrigerant circuit 10, leading to a failure of the compressor 11.

[0069] Fig. Figure 8 shows a diagram of a refrigerant circuit to illustrate a first example of the refrigerant flow in an air conditioning system according to embodiment 1 under the condition of a valve switching fault when switching between operating modes. The first example corresponds to the refrigerant flow when the four-way valve 12 is blocked and does not switch when switching from cooling to heating mode, or when the first three-way valve 16a and the second three-way valve 16b are blocked and do not switch when switching from heating to cooling mode.

[0070] As in Fig. As shown in Figure 8, the four-way valve 12 is in the second position, in which the first port G is connected to the third port F and the second port E to the fourth port H. The first three-way valve 16a and the second three-way valve 16b are in the first position. In the first three-way valve 16a, the sixth port Aa is connected to the seventh port Da and the fifth port Ca to the eighth port Ba. In the second three-way valve 16b, the sixth port Ab is connected to the seventh port Db and the fifth port Cb to the eighth port Bb.

[0071] The refrigerant exiting compressor 11 is split into two streams, one flowing towards bypass expansion valve 18 and the other towards four-way valve 12. The refrigerant flowing towards four-way valve 12 passes through the first port G and the third port F of four-way valve 12 and then through check valve 19. This refrigerant then merges with the refrigerant exiting bypass expansion valve 18 on the downstream side of the valve. After merging on the downstream side of bypass expansion valve 18, the refrigerant is split into two streams, one flowing towards the first three-way valve 16a and the other towards the second three-way valve 16b.

[0072] At the first three-way valve 16a, the refrigerant flows into the fifth port Ca of the first three-way valve 16a and flows out of the eighth port Ba. The eighth port Ba of the first three-way valve 16a is closed to prevent the refrigerant from escaping, and the refrigerant flowing out of the eighth port Ba is retained. At the second three-way valve 16b, the refrigerant flows into the fifth port Cb of the second three-way valve 16b and flows out of the eighth port Bb. The eighth port Bb of the second three-way valve 16b is closed to prevent the refrigerant from escaping, and the refrigerant flowing out of the eighth port Bb is retained.

[0073] As described above, in the first example, the refrigerant discharged by compressor 11 is retained immediately after exiting the first three-way valve 16a and the second three-way valve 16b and does not flow further through the refrigerant circuit 10. In other words, the refrigerant exiting compressor 11 is not drawn into compressor 11. Under such conditions, continuous operation of compressor 11 can cause it to operate at an abnormally high pressure, leading to compressor failure.

[0074] Fig. Figure 9 shows a diagram of a refrigerant circuit to illustrate a second example of the refrigerant flow in an air conditioning system according to embodiment 1 under the condition of a valve switching fault when switching between operating modes. The second example corresponds to the refrigerant flow when the four-way valve 12 is blocked and does not switch when switching from heating to cooling mode, or when the first three-way valve 16a and the second three-way valve 16b are blocked and do not switch when switching from cooling to heating mode.

[0075] As in Fig. As shown in Figure 9, the four-way valve 12 is in the first position, in which the first port G is connected to the fourth port H and the second port E to the third port F. The first three-way valve 16a and the second three-way valve 16b are in the second position. In the first three-way valve 16a, the sixth port Aa is connected to the eighth port Ba and the fifth port Ca to the seventh port Da. In the second three-way valve 16b, the sixth port Ab is connected to the eighth port Bb and the fifth port Cb to the seventh port Db.

[0076] The refrigerant discharged by compressor 11 is split into two streams, one flowing towards the bypass expansion valve 18 and a second flowing towards the four-way valve 12. The refrigerant flowing towards the four-way valve 12 passes through the first port G and the fourth port H of the four-way valve 12 and then enters the interior heat exchanger 13. Of the refrigerant flowing towards the bypass expansion valve 18, a portion is retained by the check valve 19, and the remaining portion is split into two streams, one flowing in a first direction towards the first three-way valve 16a and a second flowing in a second direction towards the second three-way valve 16b.

[0077] At the first three-way valve 16a, the refrigerant flows into the fifth port Ca of the first three-way valve 16a and flows out of the seventh port Da. The refrigerant leaving the first three-way valve 16a enters the first outdoor heat exchanger 15a. At the second three-way valve 16b, the refrigerant flows into the fifth port Cb of the second three-way valve 16b and flows out of the seventh port Db. The refrigerant leaving the second three-way valve 16b enters the second outdoor heat exchanger 15b.

[0078] When the refrigerant flows through the refrigerant circuit 10, as in Fig. As shown in Figure 9, the amount of refrigerant to be drawn into compressor 11 gradually decreases, eventually resulting in no refrigerant being available for intake into compressor 11. Under such conditions, continuous operation of compressor 11 can cause the motor located within compressor 11 to reach an abnormally high temperature, leading to demagnetization of the motor. This can result in compressor failure.

[0079] According to embodiment 1, a method for detecting valve switching errors is carried out to detect switching errors at the four-way valve 12, the first three-way valve 16a, or the second three-way valve 16b. This method is executed by the external control unit 50. [Valve switching fault detection method]

[0080] The method for detecting valve switching errors is described below. The valve switching error detection method according to embodiment 1 comprises a four-way valve switching error detection method for detecting switching errors in the four-way valve 12 and a three-way valve switching error detection method for detecting switching errors in the first three-way valve 16a and the second three-way valve 16b.

[0081] The four-way valve switching fault detection procedure is performed to determine whether the four-way valve 12 switches normally when switching between the operating modes of the air conditioning system 100. The three-way valve switching fault detection procedure is performed to determine whether the first three-way valve 16a and the second three-way valve 16b switch normally when switching between the operating modes of the air conditioning system 100. (Four-way valve switching fault detection method)

[0082] Fig. Figure 10 shows a flowchart illustrating an example of a four-way valve switching fault detection method for an air conditioning system according to embodiment 1. In step S1, the operating status determination unit 52 of the external controller 50 determines the operating status of the air conditioning system 100. In this example, the operating status determination unit 52 determines whether the operating status is heating or cooling mode. The determination process is not limited to this example. The operating status determination unit 52 can determine which operating status, including defrosting mode or simultaneous heating / defrosting mode, is the operating status of the air conditioning system 100.

[0083] If it is determined that the operating status of air conditioner 100 is heating mode (step S1: heating mode), the procedure continues with step S2. If it is determined that the operating status of air conditioner 100 is cooling mode (step S1: cooling mode), the procedure continues with step S6.

[0084] In step S2, the information acquisition unit 51 receives the interior temperature measured by the interior temperature sensor 33 and the interior pipe temperature measured by the interior pipe temperature sensor 32. The temperature difference calculation unit 53 calculates the temperature difference ΔT1 between the received interior temperature and the interior pipe temperature.

[0085] In step S3, the comparison unit 54 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 53 with the first temperature difference threshold value T stored in the storage unit 55. th1If, as a result of the comparison, the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T th1 If (Yes in step S3), the external control unit 50 determines that the four-way valve 12 operates normally in heating mode. The process, which includes a series of procedures, is then terminated.

[0086] If the temperature difference ΔT1 is smaller than the first temperature difference threshold T th1 If the answer is no (No in step S3), the procedure continues with step S4. In step S4, the information acquisition unit 51 receives the current value I of the current to the compressor 11 measured by the current sensor 34. Then, the comparison unit 54 compares the current value I received from the information acquisition unit 51 with the current threshold value I stored in the storage unit 55. th .

[0087] If, as a result of the comparison, the current value I is greater than the current threshold value I thIf (Yes in step S4), the external control 50 determines that the four-way valve 12 is not operating normally in heating mode and that the compressor 11 is therefore likely to have an unusually high pressure, and stops the compressor 11 in step S5. If the current value I is less than or equal to the current threshold value I th If the value is "No" in step S4, the procedure returns to step S2. The procedures of steps S2 to S4 are repeated until the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T. th1 is.

[0088] In step S6, the information acquisition unit 51 receives the interior temperature measured by the interior temperature sensor 33 and the interior pipe temperature measured by the interior pipe temperature sensor 32. The temperature difference calculation unit 53 calculates the temperature difference ΔT1 between the received interior temperature and the interior pipe temperature.

[0089] In step S7, the comparison unit 54 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 53 with the first temperature difference threshold value T stored in the storage unit 55. th1 If, as a result of the comparison, the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T th1 If (Yes in step S7), the external control 50 determines that the four-way valve 12 operates normally in cooling mode. The procedure, which includes such a series of procedures, is terminated.

[0090] If the temperature difference ΔT1 is smaller than the first temperature difference threshold T th1If the answer is no (No in step S7), the procedure continues with step S8. In step S8, the information acquisition unit 51 receives the outlet temperature of the refrigerant discharged by the compressor 11, measured by the outlet temperature sensor 31, and the interior duct temperature, measured by the interior duct temperature sensor 32. The temperature difference calculation unit 53 calculates the temperature difference ΔT2 between the received outlet temperature and the interior duct temperature.

[0091] In step S9, the comparison unit 54 compares the temperature difference ΔT2 calculated by the temperature difference calculation unit 53 with the second temperature difference threshold T stored in the storage unit 55. th2 If, as a result of the comparison, the temperature difference ΔT2 is greater than or equal to the second temperature difference threshold T th2If (Yes in step S9), the external control 50 determines that the four-way valve 12 is not operating normally in cooling mode and accordingly determines that the motor temperature in the compressor 11 is likely to reach an unusually high temperature because the refrigerant is not flowing back to the compressor 11. In step S10, the external control 50 stops the compressor 11. If the temperature difference ΔT2 is less than the second temperature difference threshold T th2 If the value is "No" in step S9, the procedure returns to step S6. The procedures of steps S6 to S9 are repeated until the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T. th1 is.

[0092] As described above, in the four-way valve switching fault detection method, during heating operation, if the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T th1 is and the current value I of the current to compressor 11 is greater than the current threshold value I th A switching error has been detected at the four-way valve 12.

[0093] As in Fig. As shown in Figure 8, a switching fault at the four-way valve 12 when switching to heating mode of the air conditioning system 100 causes the refrigerant delivered by the compressor 11 to be retained at the first three-way valve 16a and the second three-way valve 16b. Under these conditions, the refrigerant does not flow into and out of the interior heat exchanger 13, so the interior line temperature is not increased by the refrigerant flowing through the interior heat exchanger 13 and does not approach the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0094] Since the refrigerant exiting compressor 11 is retained at the first three-way valve 16a and the second three-way valve 16b, high-pressure conditions prevail in the passage at the compressor 11 outlet. Consequently, the outlet pressure of compressor 11 is subject to high-pressure conditions. Because compressor 11 discharges the refrigerant at the outlet under high-pressure conditions, the current value I rises abnormally at this time.

[0095] If the operating status of the air conditioner 100 is heating mode, then according to embodiment 1, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the current value I is unusually high (the current value I is greater than the current threshold value I) th ), the occurrence of a switching error at the four-way valve 12 is detected.

[0096] In the four-way valve switching fault detection method during cooling operation, if the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T th1 is and the temperature difference ΔT2 between the outlet temperature of the compressor 11 and the interior duct temperature is greater than or equal to the second temperature difference threshold T th2 A switching error has been detected at the four-way valve 12.

[0097] As in Fig. As shown in Figure 9, a switching fault at the four-way valve 12 during the switchover to cooling mode of the air conditioning system 100 causes the refrigerant discharged by the compressor 11 to be retained in the interior heat exchanger 13, the first exterior heat exchanger 15a, and the second exterior heat exchanger 15b. Consequently, the refrigerant does not flow back to the compressor 11. Under these conditions, the refrigerant does not flow through the interior heat exchanger 13, so the interior line temperature is approximately equal to the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0098] Since the refrigerant exiting compressor 11 is retained in the interior heat exchanger 13, the first exterior heat exchanger 15a, and the second exterior heat exchanger 15b, the refrigerant does not return to compressor 11. Consequently, the temperature of the motor inside compressor 11 rises because the motor cannot be cooled by the refrigerant within the compressor. The outlet temperature of compressor 11 increases to a high temperature as the motor temperature rises.

[0099] If the operating status of the air conditioner 100 is cooling mode, then according to embodiment 1, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the outlet temperature of compressor 11 is unusually high (the temperature difference ΔT2 is greater than or equal to the second temperature difference threshold T) th2), the occurrence of a switching error at the four-way valve 12 is detected. (Three-way valve switching error detection method)

[0100] Fig. Figure 11 shows a flowchart illustrating an example of a three-way valve switching fault detection method for an air conditioning system according to embodiment 1. In step S21, the operating status determination unit 52 determines the operating status of the air conditioning system 100. In this example, the operating status determination unit 52 determines whether the operating status is cooling mode or heating mode. The determination process is not limited to this example. The operating status determination unit 52 can determine which operating status, including defrosting mode or simultaneous heating / defrosting mode, is the operating status of the air conditioning system 100.

[0101] If it is determined that the operating status of air conditioner 100 is cooling mode (step S21: Cooling mode), the procedure continues with step S22. If it is determined that the operating status of air conditioner 100 is heating mode (step S21: Heating mode), the procedure continues with step S26.

[0102] In step S22, the information acquisition unit 51 receives the interior temperature measured by the interior temperature sensor 33 and the interior pipe temperature measured by the interior pipe temperature sensor 32. The temperature difference calculation unit 53 calculates the temperature difference ΔT1 between the received interior temperature and the interior pipe temperature.

[0103] In step S23, the comparison unit 54 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 53 with the first temperature difference threshold value T stored in the storage unit 55. th1If, as a result of the comparison, the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T th1 If (Yes in step S23), the external control 50 determines that the first three-way valve 16a and the second three-way valve 16b operate normally in cooling mode. The process, which includes a series of procedures, is terminated.

[0104] If the temperature difference ΔT1 is smaller than the first temperature difference threshold T th1 If the answer is no (No in step S23), the procedure continues with step S24. In step S24, the information acquisition unit 51 receives the current value I of the current to the compressor 11 measured by the current sensor 34. Then, the comparison unit 54 compares the current value I received from the information acquisition unit 51 with the current threshold value I stored in the storage unit 55. th If, as a result of the comparison, the current value I is greater than the current threshold value I thIf (Yes in step S24), the external controller 50 determines that the first three-way valve 16a and / or the second three-way valve 16b is not operating normally in cooling mode and that the compressor 11 is therefore likely to have an abnormally high pressure, and consequently stops the compressor 11 in step S25. If the current value I is less than or equal to the current threshold value I th If the value is "No" in step S24, the procedure returns to step S22. The procedures of steps S22 to S24 are repeated until the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T. th1 is.

[0105] In step S26, the information acquisition unit 51 receives the interior temperature measured by the interior temperature sensor 33 and the interior pipe temperature measured by the interior pipe temperature sensor 32. The temperature difference calculation unit 53 calculates the temperature difference ΔT1 between the received interior temperature and the interior pipe temperature.

[0106] In step S27, the comparison unit 54 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 53 with the first temperature difference threshold value T stored in the storage unit 55. th1 If, as a result of the comparison, the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T th1If (Yes in step S27), the external control 50 determines that the first three-way valve 16a and the second three-way valve 16b operate normally in heating mode. The procedure, which includes such a series of procedures, is terminated.

[0107] If the temperature difference ΔT1 is smaller than the first temperature difference threshold T th1 If the answer is no (No in step S27), the procedure continues with step S28. In step S28, the information acquisition unit 51 receives the outlet temperature of the refrigerant discharged by the compressor 11, measured by the outlet temperature sensor 31, and the indoor duct temperature, measured by the indoor duct temperature sensor 32. The temperature difference calculation unit 53 calculates the temperature difference ΔT2 between the received outlet temperature and the indoor duct temperature.

[0108] In step S29, the comparison unit 54 compares the temperature difference ΔT2 calculated by the temperature difference calculation unit 53 with the second temperature difference threshold T stored in the storage unit 55. th2 If, as a result of the comparison, the temperature difference ΔT2 is greater than or equal to the second temperature difference threshold T th2 If (Yes in step S29), the external control 50 determines that the first three-way valve 16a and / or the second three-way valve 16b is not operating normally in heating mode and accordingly determines that the motor temperature in the compressor 11 is likely to reach an unusually high temperature because the refrigerant is not flowing back to the compressor 11. In step S30, the external control 50 stops the compressor 11. If the temperature difference ΔT2 is less than the second temperature difference threshold T th2If (No in step S29), the procedure returns to step S26. The procedures of steps S26 to S29 are repeated until the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T. th1 is.

[0109] As described above, in the three-way valve switching fault detection method, if during cooling operation the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T th1 is and the current value I of the current to compressor 11 is greater than the current threshold value I th This indicates a switching error of the first three-way valve 16a and / or the second three-way valve 16b.

[0110] As in Fig. As shown in Figure 8, a switching fault of the first three-way valve 16a and / or the second three-way valve 16b when switching to cooling mode of the air conditioning system 100 causes the refrigerant delivered by the compressor 11 to be retained at the first three-way valve 16a and the second three-way valve 16b. Under these conditions, the refrigerant does not flow into and out of the interior heat exchanger 13, so the interior line temperature is not increased by the refrigerant flowing through the interior heat exchanger 13 and does not approach the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0111] Since the refrigerant exiting compressor 11 is retained at the first three-way valve 16a and the second three-way valve 16b, a high pressure prevails in the passage at the outlet of compressor 11. Consequently, the outlet pressure of compressor 11 is subject to high-pressure conditions. Because compressor 11 discharges the refrigerant at the outlet under high-pressure conditions, the current I rises unusually sharply at this time.

[0112] If the operating status of the air conditioner 100 is cooling mode, then according to embodiment 1, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the current value I is unusually high (the current value I is greater than the current threshold value I) th ), the occurrence of a switching error at the first three-way valve 16a and / or at the second three-way valve 16b is detected.

[0113] In the three-way valve switching fault detection method, during heating operation, if the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T th1 and the temperature difference ΔT2 between the outlet temperature of compressor 11 and the interior duct temperature is greater than or equal to the second temperature difference threshold T th2 is, a switching error has been detected at the first three-way valve 16a and / or at the second three-way valve 16b.

[0114] As in Fig. As shown in Figure 9, a switching fault of the first three-way valve 16a and / or the second three-way valve 16b when switching to heating mode of the air conditioning system 100 causes the refrigerant discharged by the compressor 11 to be retained in the interior heat exchanger 13, the first exterior heat exchanger 15a, and the second exterior heat exchanger 15b. Consequently, the refrigerant does not flow back to the compressor 11. Under these conditions, the refrigerant does not flow through the interior heat exchanger 13, so the interior line temperature is approximately equal to the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0115] Since the refrigerant exiting compressor 11 is retained in the interior heat exchanger 13, the first exterior heat exchanger 15a, and the second exterior heat exchanger 15b, the refrigerant does not return to compressor 11. Consequently, the temperature of the motor inside compressor 11 rises because the motor cannot be cooled by the refrigerant within the compressor. The outlet temperature of compressor 11 increases to a high temperature as the motor temperature rises.

[0116] If the operating status of the air conditioner 100 is heating mode, then according to embodiment 1, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the outlet temperature of compressor 11 is unusually high (the temperature difference ΔT2 is greater than or equal to the second temperature difference threshold T) th2), the occurrence of a switching error at the first three-way valve 16a and / or at the second three-way valve 16b is detected.

[0117] In the example of embodiment 1 described above, the four-way valve switching fault detection method and the three-way valve switching fault detection method are performed at different times. These methods can be performed in any other way. For example, the four-way valve switching fault detection method and the three-way valve switching fault detection method can be performed simultaneously.

[0118] Furthermore, a user can be notified of an anomaly at one of the valves if a switching error repeatedly occurs at the four-way valve 12, the first three-way valve 16a, or the second three-way valve 16b. For example, if a switching error repeatedly occurs at the four-way valve 12, the first three-way valve 16a, or the second three-way valve 16b, the outdoor controller 50 sends an anomaly detection signal, indicating an anomaly at one of the valves, to the indoor controller 60. In response to the received anomaly detection signal, the indoor controller 60 transmits information about the anomaly, for example, to the remote control operated by the user. This allows the user, having received the information about the anomaly, to determine its cause.

[0119] As described above, the external control unit 50 in the air conditioning system 100 according to embodiment 1 causes the outlet temperature sensor 31, the interior duct temperature sensor 32, and the interior temperature sensor 33 to measure temperatures in certain sections of the refrigerant circuit 10, and the current sensor 34 to measure the current supplied to the compressor 11. Based on the measured values ​​and the operating status of the air conditioning system 100, the external control unit 50 detects a switching fault at the four-way valve 12 or at the first three-way valve 16a and / or at the second three-way valve 16b.

[0120] According to embodiment 1, the external control unit 50 can detect a switching error at any of the valves if the measurements deviate from those indicating normal valve switching or normal valve operation. Specifically, according to embodiment 1, the air conditioning unit 100 can, for example, determine whether a switching error has occurred at one of the valves based on temperatures measured in certain sections of the refrigerant circuit 10.

[0121] According to embodiment 1, the external control unit 50 determines that a switching error has occurred at the four-way valve 12 during heating operation if the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T th1 is and the current value I is greater than the current threshold value I thAs described above, the external control unit 50 can detect a switching error at the four-way valve 12 by determining the operating status, the interior line temperature in the interior heat exchanger 13, and the current value I of the current to the compressor 11.

[0122] According to embodiment 1, the external control 50 determines that a switching error has occurred at the four-way valve 12 during cooling operation if the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T th1 is and the temperature difference ΔT2 between the outlet temperature and the interior duct temperature is greater than or equal to the second temperature difference threshold T th2As described above, the external control unit 50 can detect a switching fault at the four-way valve 12 by determining the operating status, the interior line temperature in the interior heat exchanger 13, and the outlet temperature of the compressor 11.

[0123] According to embodiment 1, the external control 50 determines that a switching error has occurred at the first three-way valve 16a or at the second three-way valve 16b during cooling operation if the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T th1 is and the current value I is greater than the current threshold value I thAs described above, the external control unit 50 can detect a switching fault at the first three-way valve 16a or at the second three-way valve 16b by determining the operating status, the interior line temperature in the interior heat exchanger 13 and the current value I of the current to the compressor 11.

[0124] According to embodiment 1, the external control unit 50 determines that a switching error has occurred at the first three-way valve 16a or at the second three-way valve 16b during heating operation if the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T th1 is and the temperature difference ΔT2 between the outlet temperature and the interior duct temperature is greater than or equal to the second temperature difference threshold T th2As described above, the external control unit 50 can detect a switching fault at the first three-way valve 16a or at the second three-way valve 16b by determining the operating status, the interior line temperature in the interior heat exchanger 13 and the outlet temperature of the compressor 11.

[0125] According to embodiment 1, the external control unit 50 stops the compressor 11 if a switching fault is detected at the four-way valve 12, the first three-way valve 16a, or the second three-way valve 16b. This reduces the risk of compressor 11 failure caused by the continued operation of the air conditioning system 100. Design 2

[0126] Embodiment 2 will now be described. Embodiment 2 differs from embodiment 1 in that a valve switching fault detection method is performed based on the temperature of the line between the first outdoor heat exchanger 15a and the first three-way valve 16a and the temperature of the line between the second outdoor heat exchanger 15b and the second three-way valve 16b. In embodiment 2, the parts corresponding to embodiment 1 are provided with the same reference numerals, and their detailed description is omitted. [Air conditioning configuration 100]

[0127] Fig. Figure 12 shows a representation of a refrigerant circuit to illustrate a configuration example for an air conditioning system according to embodiment 2. As in Fig. As shown in Figure 12, an air conditioning system 200 according to embodiment 2 comprises the refrigerant circuit 10, an external control 250, the internal control 60, the outlet temperature sensor 31, the internal line temperature sensor 32, the internal temperature sensor 33 and the current sensor 34. (First outdoor (room) pipe temperature sensor 35a and second outdoor (room) pipe temperature sensor 35b)

[0128] The air conditioning unit 200 further comprises a first outdoor duct temperature sensor 35a and a second outdoor duct temperature sensor 35b. The first outdoor duct temperature sensor 35a is attached to the duct connecting the first outdoor heat exchanger 15a to the seventh port Da of the first three-way valve 16a, measuring the surface temperature of the duct. The second outdoor duct temperature sensor 35b is attached to the duct connecting the second outdoor heat exchanger 15b to the seventh port Db of the second three-way valve 16b, measuring the surface temperature of the duct. In the following description, the surface temperature measured by the first outdoor duct temperature sensor 35a and the surface temperature measured by the second outdoor duct temperature sensor 35b can be referred to as the "first surface temperature" and the "second surface temperature," respectively. (External control 250)

[0129] Like the external control unit 50 of embodiment 1, the external control unit 250 receives information about a temperature measured by the outlet temperature sensor 31 and information about a current to the compressor 11 measured by the current sensor 34. In embodiment 2, the external control unit 250 receives information about the first surface temperature measured by the first external line temperature sensor 35a and the second surface temperature measured by the second external line temperature sensor 35b.

[0130] Fig. Figure 13 shows a functional block diagram to illustrate a configuration example for the in Fig. 12 external controls shown. As in Fig. As shown in Figure 13, the external control unit 250 comprises an information acquisition unit 151, an operating status determination unit 52, a temperature difference calculation unit 153, a comparison unit 154, and a storage unit 155. The external control unit 250 is configured, for example, as an arithmetic unit, such as a microcomputer on which software for implementing a multitude of functions is executed, or as hardware, such as circuit devices corresponding to the functions. Fig. Figure 13 shows the components for the functions relating to embodiment 2, omitting the representation of the other components.

[0131] The information acquisition unit 151 receives the surface temperatures measured by the first external line temperature sensor 35a and the second external line temperature sensor 35b, in addition to the various individual pieces of information received by the information acquisition unit 51 of embodiment 1.

[0132] Like the temperature difference calculation unit 53 of embodiment 1, the temperature difference calculation unit 153 calculates the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature. According to embodiment 2, the temperature difference calculation unit 153 calculates a temperature difference ΔT 3a between the outlet temperature measured by the outlet temperature sensor 31 and the first surface temperature measured by the first external pipe temperature sensor 35a. Furthermore, the temperature difference calculation unit 153 calculates a temperature difference AT. 3bbetween the outlet temperature measured by the outlet temperature sensor 31 and the second surface temperature measured by the second external pipe temperature sensor 35b.

[0133] The comparison unit 154 compares the various individual pieces of information. Like the comparison unit 54 of embodiment 1, the comparison unit 154 compares the temperature difference ΔT1 with the first temperature difference threshold T. th1 and compares the current value I with the current threshold value I th .

[0134] Furthermore, the comparison unit 154 according to embodiment 2 compares the temperature differences ΔT calculated by the temperature difference calculation unit 153. 3a and AT 3b with a third temperature difference threshold T th3 , which is stored in storage unit 155. The third temperature difference threshold T th3 is a predefined value for the temperature differences ΔT 3aand ΔT 3b The third temperature difference threshold T th3 is a value used to determine whether the four-way valve 12, the first three-way valve 16a and the second three-way valve 16b are switched normally.

[0135] As in the storage unit 55 according to embodiment 1, the first temperature difference threshold T is set in the storage unit 155. th1 and the current threshold I th stored. According to embodiment 2, the storage unit 155 also stores the third temperature difference threshold value T. th3 , which is used by the comparison unit 154.

[0136] As in embodiment 1, the units contained in the external control 250 can be implemented by the processing circuit 71, which is located in Fig. 3 is shown. The units contained in the external control unit 250 can be accessed via the [function / device] shown in Fig. The processor 81 and the memory 82 shown in the diagram are implemented. [Valve switching fault detection method]

[0137] A valve switching fault detection method implemented by the air conditioning system 200 according to embodiment 2 is now described. As in embodiment 1, the valve switching fault detection method according to embodiment 2 comprises a four-way valve switching fault detection method for detecting switching faults at the four-way valve 12 and a three-way valve switching fault detection method for detecting switching faults at the first three-way valve 16a and the second three-way valve 16b. (Four-way valve switching fault detection method)

[0138] Fig. Figure 14 shows a flowchart illustrating an example of a method for detecting switching errors of the four-way valve in an air conditioning system according to embodiment 2. The following description details procedures that are part of the four-way valve switching error detection method of Fig. 10 according to embodiment 1 are provided with the same reference numerals, omitting a detailed description.

[0139] In step S1, the operating status determination unit 52 of the external controller 250 determines the operating status of the air conditioner 200. In this example, the operating status determination unit 52 determines whether the operating status is heating or cooling mode. The determination process is not limited to this example. The operating status determination unit 52 can determine which operating status, including defrosting mode or simultaneous heating / defrosting mode, constitutes the operating status of the air conditioner 200.

[0140] If it is determined that the operating status of the air conditioner 200 is heating mode (step S1: heating mode), the procedure continues with step S2. The procedures of the valve switching fault detection method in steps S2 to S5 for heating mode are the same as in embodiment 1, so their description is omitted.

[0141] If, in step S1, it is determined that the operating state of the air conditioning system 200 is cooling mode (step S1: cooling mode), the procedure continues with step S6. In step S6, the information acquisition unit 151 receives the interior temperature determined by the interior temperature sensor 33 and the interior duct temperature determined by the interior duct temperature sensor 32. The temperature difference calculation unit 153 calculates the temperature difference ΔT1 between the received interior temperature and the interior duct temperature.

[0142] In step S7, the comparison unit 154 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 153 with the first temperature difference threshold value T stored in the storage unit 155. th1 If, as a result of the comparison, the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T th1If (Yes in step S7), the external control 250 determines that the four-way valve 12 operates normally in cooling mode. The procedure, which includes this series of steps, is then terminated.

[0143] If the temperature difference ΔT1 is smaller than the first temperature difference threshold T th1 If the answer is no (No in step S7), the procedure continues with step S41. In step S41, the information acquisition unit 151 receives the outlet temperature measured by the outlet temperature sensor 31, the first surface temperature measured by the first external pipe temperature sensor 35a, and the second surface temperature measured by the second external pipe temperature sensor 35b. The temperature difference calculation unit 153 calculates the temperature difference ΔT. 3a between the obtained outlet temperature and the first surface temperature. Furthermore, the temperature difference calculation unit 153 calculates the temperature difference AT. 3bbetween the obtained outlet temperature and the second surface temperature.

[0144] In step S42, the comparison unit 154 compares the temperature difference ΔT calculated by the temperature difference calculation unit 153. 3a with the third temperature difference threshold T stored in storage unit 155 th3 If the temperature difference ΔT is the result of the comparison 3a greater than or equal to the third temperature difference threshold T th3 If the temperature difference ΔT is (Yes in step S42), the procedure continues with step S43. 3a smaller than the third temperature difference threshold T th3 (No in step S42), the procedure returns to step S6.

[0145] In step S43, the comparison unit 154 compares the temperature difference AT calculated by the temperature difference calculation unit 153. 3bwith the third temperature difference threshold T stored in storage unit 155 th3 If the temperature difference AT is the result of the comparison 3b greater than or equal to the third temperature difference threshold T th3 If (Yes in step S43), the external control 250 determines that the four-way valve 12 is operating abnormally in cooling mode and accordingly determines that the motor temperature in the compressor 11 is likely to reach an unusually high temperature because the refrigerant is not flowing back to the compressor 11. In step S10, the external control 250 stops the compressor 11. If the temperature difference ΔT 3b smaller than the third temperature difference threshold T th3 (No in step S43), the procedure returns to step S6.

[0146] As described above, in the four-way valve switching error detection method, a switching error at the four-way valve 12 is detected if, during heating operation, the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T. th1 is and the current value I of the current to compressor 11 is greater than the current threshold value I th is.

[0147] As with the one in Fig. In the example shown in Figure 8, a switching error at the four-way valve 12 when switching to heating mode of the air conditioning system 200 causes the refrigerant delivered by the compressor 11 to be retained at the first three-way valve 16a and the second three-way valve 16b. Under these conditions, the refrigerant does not flow into and out of the interior heat exchanger 13, so the interior line temperature is not increased by the refrigerant flowing through the interior heat exchanger 13 and does not approach the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0148] Since the refrigerant exiting compressor 11 is retained at the first three-way valve 16a and the second three-way valve 16b, a high pressure prevails in the outlet area of ​​compressor 11. Consequently, the outlet pressure of compressor 11 is subject to high-pressure conditions. Because compressor 11 discharges the refrigerant in the outlet area under high-pressure conditions, the current value I rises unusually sharply at this time.

[0149] If the operating status of the air conditioner 200 is heating mode, then according to embodiment 2, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the current value I is unusually high (the current value I is greater than the current threshold value I) th ), the occurrence of a switching error at the four-way valve 12 can be determined.

[0150] In the four-way valve switching error detection method, a switching error at the four-way valve 12 is detected if, during cooling operation, the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T. th1 is when the temperature difference ΔT 3a between the outlet temperature of compressor 11 and the first surface temperature greater than or equal to the third temperature difference threshold T th3 is and the temperature difference AT 3b between the outlet temperature and the second surface temperature greater than or equal to the third temperature difference threshold T th3 is.

[0151] As with the one in Fig. In the example shown in Figure 9, a switching error at the four-way valve 12 during the switchover to cooling mode of the air conditioning system 200 causes the refrigerant discharged by the compressor 11 to be retained in the interior heat exchanger 13, the first exterior heat exchanger 15a, and the second exterior heat exchanger 15b. Consequently, the refrigerant does not flow back to the compressor 11. Under these conditions, the refrigerant does not flow through the interior heat exchanger 13, so the interior line temperature is approximately equal to the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0152] Since the refrigerant does not flow through the first external heat exchanger 15a and the second external heat exchanger 15b, the first surface temperature and the second surface temperature do not increase. Since the refrigerant does not flow back to the compressor 11, the temperature of the motor in the compressor 11 increases, as the motor cannot be cooled by the refrigerant in the compressor. The outlet temperature of the compressor 11 rises to a high temperature as the motor temperature increases. In other words, the temperature difference ΔT 3a between the outlet temperature of compressor 11 and the first surface temperature and the temperature difference ΔT 3b between the outlet temperature of the compressor 11 and the second surface temperature is greater than the temperature differences when the first three-way valve 16a and the second three-way valve 16b are switched normally.

[0153] If the operating status of the air conditioner 200 is cooling mode, then according to embodiment 2, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold Tt) h1 ) and the temperature differences ΔT 3a and ΔT 3b are large (the temperature differences ΔT 3a and ΔT 3b are greater than or equal to the third temperature difference threshold T th3 ), the occurrence of a switching error at the four-way valve 12 can be determined. (Three-way valve switching error detection method)

[0154] Fig. Figure 15 shows a flowchart illustrating an example of a three-way valve switching fault detection method for an air conditioning system according to embodiment 2. The following description outlines procedures associated with the three-way valve switching fault detection method of Fig. 11 according to embodiment 1, are identical, provided with the same reference numerals, and their detailed description may be omitted.

[0155] In step S21, the operating status determination unit 52 determines the operating status of the air conditioning unit 200. In this example, the operating status determination unit 52 determines whether the operating status is cooling mode or heating mode. The determination process is not limited to this example. The operating status determination unit 52 can determine which operating status, including defrosting mode or simultaneous heating / defrosting mode, is the operating status of the air conditioning unit 200.

[0156] If it is determined that the operating status of air conditioner 200 is cooling mode (step S21: cooling mode), the procedure continues with step S22. The procedures of steps S22 to S25 for cooling mode in the three-way valve switching fault detection procedure are the same as in embodiment 1, and their description is omitted.

[0157] If, in step S21, it is determined that the operating status of the air conditioning system 200 is heating mode (step S21: heating mode), the procedure continues with step S26. In step S26, the information acquisition unit 151 receives the indoor temperature measured by the indoor temperature sensor 33 and the indoor duct temperature measured by the indoor duct temperature sensor 32. The temperature difference calculation unit 153 calculates the temperature difference ΔT1 between the received indoor temperature and the indoor duct temperature.

[0158] In step S27, the comparison unit 154 compares the temperature difference ΔT1 calculated by the temperature difference calculation unit 153 with the first temperature difference threshold value T stored in the storage unit 155. th1 If, as a result of the comparison, the temperature difference ΔT1 is greater than or equal to the first temperature difference threshold T th1 If (Yes in step S27), the external control 250 determines that the first three-way valve 16a and the second three-way valve 16b operate normally in heating mode. The procedure, which includes this series of steps, is then terminated.

[0159] If the temperature difference ΔT1 is smaller than the first temperature difference threshold T th1If the answer is no (No in step S27), the procedure continues with step S51. In step S51, the information acquisition unit 151 receives the outlet temperature measured by the outlet temperature sensor 31, the first surface temperature measured by the first external pipe temperature sensor 35a, and the second surface temperature measured by the second external pipe temperature sensor 35b. The temperature difference calculation unit 153 calculates the temperature difference ΔT. 3a between the obtained outlet temperature and the first surface temperature. Furthermore, the temperature difference calculation unit 153 calculates the temperature difference ΔT. 3b between the obtained outlet temperature and the second surface temperature.

[0160] In step S52, the comparison unit 154 compares the temperature difference ΔT calculated by the temperature difference calculation unit 153. 3awith the third temperature difference threshold T stored in storage unit 155 th3 If the temperature difference ΔT is the result of the comparison 3a greater than or equal to the third temperature difference threshold T th3 If (Yes in step S52), the procedure continues with step S53. If the temperature difference ΔT is 3a smaller than the third temperature difference threshold T th3 (No in step S52), the procedure returns to step S26.

[0161] In step S53, the comparison unit 154 compares the temperature difference ΔT calculated by the temperature difference calculation unit 153. 3b with the third temperature difference threshold T stored in storage unit 155 th3 If the temperature difference ΔT is the result of the comparison 3b greater than or equal to the third temperature difference threshold T th3If (Yes in step S53), the external control 250 determines that the first three-way valve 16a and / or the second three-way valve 16b is not operating normally in heating mode and accordingly determines that the temperature of the motor in the compressor 11 is likely to reach an unusually high temperature because the refrigerant is not flowing back to the compressor 11. In step S30, the external control 250 stops the compressor 11. If the temperature difference ΔT 3b smaller than the third temperature difference threshold T th3 (No in step S53), the procedure returns to step S26.

[0162] As described above, in the three-way valve switching fault detection method, if during cooling operation the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T th1is and the current value I of the current to compressor 11 is greater than the current threshold value I th This indicates a switching error of the first three-way valve 16a and / or the second three-way valve 16b.

[0163] As in the Fig. In the example shown in Figure 8, a switching error of the first three-way valve 16a and / or the second three-way valve 16b when switching to cooling mode of the air conditioning system 200 leads to the refrigerant delivered by the compressor 11 being retained at the first three-way valve 16a and the second three-way valve 16b. Under these conditions, the refrigerant does not flow into and out of the interior heat exchanger 13, so that the interior line temperature is not increased by the refrigerant flowing through the interior heat exchanger 13 and does not approach the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is therefore small.

[0164] Since the refrigerant exiting compressor 11 is retained at the first three-way valve 16a and the second three-way valve 16b, a high pressure prevails in the outlet area of ​​compressor 11. Consequently, the outlet pressure of compressor 11 is subject to high-pressure conditions. Because compressor 11 discharges the refrigerant in the outlet area under high-pressure conditions, the current value I rises unusually sharply at this time.

[0165] If the operating status of the air conditioner 200 is cooling mode, then according to embodiment 2, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the current value I is unusually high (the current value I is greater than the current threshold value I) th ), the occurrence of a switching error of the first three-way valve 16a and / or the second three-way valve 16b can be determined.

[0166] In the three-way valve switching fault detection method, if the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T during heating operation, th1 is the temperature difference ΔT 3a between the outlet temperature of compressor 11 and the first surface temperature greater than or equal to the third temperature difference threshold T th3 is and the temperature difference ΔT 3b between the outlet temperature and the second surface temperature greater than or equal to the third temperature difference threshold T th3 This indicates a switching error of the first three-way valve 16a and / or the second three-way valve 16b.

[0167] As in the Fig.In the example shown in Figure 9, a switching error of the first three-way valve 16a and / or the second three-way valve 16b when switching to heating mode of the air conditioning system 200 causes the refrigerant delivered by the compressor 11 to be retained in the interior heat exchanger 13, the first exterior heat exchanger 15a, and the second exterior heat exchanger 15b. Consequently, the refrigerant does not flow back to the compressor 11. Under these conditions, the refrigerant does not flow through the interior heat exchanger 13, so the interior line temperature is approximately equal to the interior temperature. In other words, the temperature difference ΔT1 between the interior temperature and the interior line temperature is small.

[0168] Since the refrigerant does not flow through the first external heat exchanger 15a and the second external heat exchanger 15b, the first surface temperature and the second surface temperature do not increase. The refrigerant does not flow back to the compressor 11, so the temperature of the motor in the compressor 11 increases because the motor cannot be cooled by the refrigerant in the compressor. The outlet temperature of the compressor 11 rises to a high temperature as the motor temperature increases. In other words, the temperature difference ΔT 3a between the outlet temperature of compressor 11 and the first surface temperature and the temperature difference ΔT 3b between the outlet temperature of the compressor 11 and the second surface temperature greater than the temperature differences when the first three-way valve 16a and the second three-way valve 16b are switched normally.

[0169] If the operating status of the air conditioner 200 is heating mode, then according to embodiment 2, if the temperature difference ΔT1 is small (the temperature difference ΔT1 is smaller than the first temperature difference threshold T) th1 ) and the temperature differences ΔT 3a and ΔT 3b are large (the temperature differences ΔT 3a and ΔT 3b are greater than or equal to the third temperature difference threshold T th3 ), the occurrence of a switching error at the first three-way valve 16a and / or second three-way valve 16b can be determined.

[0170] As described above, the external control unit 250 of the air conditioning system 200 according to embodiment 2 causes the outlet temperature sensor 31, the interior duct temperature sensor 32, the interior temperature sensor 33, the first exterior duct temperature sensor 35a, and the second exterior duct temperature sensor 35b to measure temperatures at certain sections in the refrigerant circuit 10, and the current sensor 34 to measure the current to the compressor 11. Based on the measurements and the operating status, the external control unit 250 detects a switching fault at the four-way valve 12 or at the first three-way valve 16a and / or the second three-way valve 16b.

[0171] As described above, the air conditioning system 200 according to embodiment 2, like the air conditioning system 100 according to embodiment 1, can determine whether a switching error has occurred at one of the valves, for example by using the temperatures measured at some sections in the refrigerant circuit 10.

[0172] According to embodiment 2, the external control unit 250 determines that a switching error has occurred at the four-way valve 12 if, during heating operation, the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T. th1 is and the current value I is greater than the current threshold value I th As described above, the external control unit 250 can detect a switching error at the four-way valve 12 by determining the operating status, the interior line temperature in the interior heat exchanger 13, and the current value I of the current to the compressor 11.

[0173] According to embodiment 2, the external control unit 250 determines that a switching error has occurred at the four-way valve 12 if, during cooling operation, the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T. th1is the temperature difference ΔT 3a between the outlet temperature and the first surface temperature greater than or equal to the third temperature difference threshold T th3 is and the temperature difference ΔT 3b between the outlet temperature and the second surface temperature greater than or equal to the third temperature difference threshold T th3 As described above, the external control unit 250 can detect a switching error at the four-way valve 12 by determining the operating status, the interior line temperature in the interior heat exchanger 13, the first surface temperature and the second surface temperature.

[0174] According to embodiment 2, the external control unit 250 determines that a switching error has occurred at the first three-way valve 16a or at the second three-way valve 16b if, during cooling operation, the temperature difference ΔT1 between the interior temperature and the interior duct temperature is less than the first temperature difference threshold T th1 is and the current value I is greater than the current threshold value I th As described above, the external control 250 can detect a switching error at the first three-way valve 16a or at the second three-way valve 16b by determining the operating status, the interior line temperature in the interior heat exchanger 13 and the current value I of the current to the compressor 11.

[0175] According to embodiment 2, the external control unit 250 determines that a switching error has occurred at the first three-way valve 16a or at the second three-way valve 16b if, during heating operation, the temperature difference ΔT1 between the indoor temperature and the indoor duct temperature is less than the first temperature difference threshold T th1 is the temperature difference ΔT 3a between the outlet temperature and the first surface temperature greater than or equal to the third temperature difference threshold T th3 is and the temperature difference ΔT 3b between the outlet temperature and the second surface temperature greater than or equal to the third temperature difference threshold T th3As described above, the external control 250 can detect a switching error at the first three-way valve 16a or at the second three-way valve 16b by determining the operating status, the interior line temperature in the interior heat exchanger 13, the first surface temperature and the second surface temperature.

[0176] According to embodiment 2, the external control unit 250 stops the compressor 11 if a switching fault is detected at the four-way valve 12, the first three-way valve 16a, or the second three-way valve 16b. This reduces the risk of compressor 11 failure caused by the continued operation of the air conditioning system 200. Reference symbol list 10 Refrigerant circuit, 11 Compressor, 12 four-way valve, 13 interior heat exchangers, 14 Expansion valve, 15a first external heat exchanger, 15b second external heat exchanger, 16a first three-way valve, 16b second three-way valve, 17a, 17b capillary tube, 18 Bypass expansion valve, 19 Check valve, 31 Outlet temperature sensor, 32 Interior line temperature sensor, 33 Interior temperature sensor, 34 Current sensor, 35a first external line temperature sensor, 35b second external line temperature sensor, 50, 250 external control, 51, 151 Information gathering unit, 52 Operating status determination unit, 53, 153 Temperature difference calculation unit, 54, 154 comparison unit, 55, 155 storage unit, 60 Interior control, 71 Processing circuit, 81 processor, 82 memory slots, 100, 200 air conditioner

Claims

[1] Air conditioning (100, 200) which has: a four-way valve (12) having a first port (G), a second port (E), a third port (F) and a fourth port (H); a first three-way valve (16a) and a second three-way valve (16b), each having a fifth port (Ca, Cb), a sixth port (Aa, Ab), a seventh port (Da, Db) and an eighth port (Ba, Bb), where the eighth connection (Ba, Bb) is closed; a compressor (11) having an outlet area connected to the first port (G) and an intake area connected to the second port (E) and the sixth ports (Aa, Ab) of the first and second three-way valves (16a, 16b), respectively, wherein the compressor (11) is configured to draw in refrigerant, compress the refrigerant and releases the compressed refrigerant; an interior heat exchanger (13) connected to the fourth port (H) and designed to exchange heat between the refrigerant and the interior air; an expansion valve (14) connected to the interior heat exchanger (13) and designed to reduce the pressure of the refrigerant; a first external heat exchanger (15a) arranged between the expansion valve (14) and the seventh port (Da) of the first three-way valve (16a), wherein the first external heat exchanger (15a) is designed that it exchanges heat between the refrigerant and the outside air; a second external heat exchanger (15b) arranged between the expansion valve (14) and the seventh port (Db) of the second three-way valve (16b), wherein the second external heat exchanger (15b) is designed to exchange heat between the refrigerant and the outside air; a bypass expansion valve (18) arranged between the outlet area of ​​the compressor (11) and the fifth ports (Ca, Cb) of the first and second three-way valves (16a, 16b) respectively; a check valve (19) having a first end connected to the third port (F) and a second end connected between the bypass expansion valve (18) and the fifth ports (Ca, Cb) of the first and second three-way valves (16a, 16b), respectively, wherein the check valve (19) is designed such that the refrigerant can flow in one direction from the first end to the second end, but the refrigerant cannot flow in the opposite direction; an outlet temperature sensor (31) designed to measure the outlet temperature of the refrigerant discharged by the compressor (11); an interior duct temperature sensor (32) designed to measure the duct temperature of a duct through which the refrigerant flows in the interior heat exchanger (13); an interior temperature sensor (33) designed to measure an interior temperature which is the temperature of the interior air; a current sensor (34) designed to measure the current value of the current supplied to the compressor (11); and a control unit (50, 250) designed to detect a switching fault at the four-way valve (12), the first three-way valve (16a) and the second three-way valve (16b), the air conditioning system (100, 200) can perform: a heating operation in which the first and second external heat exchangers (15a, 15b) are operated as evaporators and the internal heat exchanger (13) as a condenser, a defrosting operation and a cooling operation, in which the first and the second external heat exchanger (15a, 15b) are each operated as condensers, and a simultaneous heating / defrosting operation in which the first external heat exchanger (15a) or the second external heat exchanger (15b) is operated as an evaporator and the other of the two first and second external heat exchanger (15a, 15b) and the The interior heat exchanger (13) is operated as a condenser, the control (50, 250) being designed to operate using the temperature input from the outlet temperature sensor (31), the Interior line temperature sensor (32) and the The temperature measured by the interior temperature sensor (33) and the current value measured by the current sensor (34), taking into account the operating status, detects a switching error at the four-way valve (12), the first three-way valve (16a) or the second three-way valve (16b). [2] Air conditioning system (100, 200) according to claim 1, wherein the control system (50, 250) is configured to determine that a switching fault occurs at the four-way valve (12) when, during heating operation, the temperature difference between the room temperature and the line temperature is less than a first temperature difference threshold and the current value is greater than a current threshold. [3] Air conditioning system (100, 200) according to claim 1 or 2, wherein the control system (50, 250) is configured to determine that a switching fault occurs at the first three-way valve (16a) or the second three-way valve (16b) when, during cooling operation, a temperature difference between the interior temperature and the line temperature is less than a first temperature difference threshold and the current value is greater than a current threshold. [4] Air conditioning system (100) according to one of claims 1 to 3, wherein the control (50) is configured to determine that a switching fault occurs at the four-way valve (12) when, during cooling operation, a temperature difference between the interior temperature and the duct temperature is less than a first temperature difference threshold and a temperature difference between the outlet temperature and the duct temperature is greater than or equal to a second temperature difference threshold. [5] Air conditioning system (100) according to one of claims 1 to 4, wherein the control (50) is configured to determine that a switching fault occurs at the first three-way valve (16a) or the second three-way valve (16b) when, during heating operation, a temperature difference between the interior temperature and the duct temperature is less than a first temperature difference threshold and a temperature difference between the outlet temperature and the duct temperature is greater than or equal to a second temperature difference threshold. [6] Air conditioning system (200) according to one of claims 1 to 3, further comprising: a first outdoor pipe temperature sensor arranged on a pipe connecting the first outdoor heat exchanger (15a) to the seventh port (Da) of the first three-way valve (16a), wherein the first outdoor pipe temperature sensor is configured to measure a first surface temperature of the pipe; and a second outdoor pipe temperature sensor arranged on a pipe connecting the second outdoor heat exchanger (15b) to the seventh port (Db) of the second three-way valve (16b), wherein the second outdoor pipe temperature sensor is configured to measure a second surface temperature of the pipe, wherein the control (250) is designed to operate using the output temperature sensor (31), the interior duct temperature sensor (32), the interior temperature sensor (33), the first outdoor line temperature sensor and from the second The external line temperature sensor detects a switching error at the four-way valve (12), at the first three-way valve (16a) or at the second three-way valve (16b) based on the temperatures measured by the external line temperature sensor and the current value measured by the current sensor (34), taking into account the operating status. [7] Air conditioning system (200) according to claim 6, wherein the control (250) is configured to determine that a switching fault occurs at the four-way valve (12) when, during cooling operation, a temperature difference between the interior temperature and the duct temperature is less than a first temperature difference threshold, a temperature difference between the outlet temperature and the first surface temperature is greater than or equal to a third temperature difference threshold, and a temperature difference between the outlet temperature and the second surface temperature is greater than or equal to the third temperature difference threshold. [8] Air conditioning system (200) according to claim 6 or 7, wherein the control (250) is configured to determine that a switching fault occurs at the first three-way valve (16a) or the second three-way valve (16b) when, during heating operation, a temperature difference between the interior temperature and the duct temperature is less than a first temperature difference threshold, a temperature difference between the outlet temperature and the first surface temperature is greater than or equal to a third temperature difference threshold, and a temperature difference between the outlet temperature and the second surface temperature is greater than or equal to the third temperature difference threshold. [9] Air conditioning system (100, 200) according to any one of claims 1 to 8, wherein the control (50, 250) is configured to stop the compressor (11) in response to the detection of a switching fault at the four-way valve (12), the first three-way valve (16a) or the second three-way valve (16b).

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