Air-conditioning device

Abstract

This air-conditioning device comprises a first operation valve provided between a compressor and an indoor heat exchanger on a gas pipe, a second operation valve provided between the expansion valve and the indoor heat exchanger on a liquid pipe, a first temperature measurement unit for measuring the temperature of the indoor heat exchanger, a second temperature measurement unit for measuring the temperature of an outdoor heat exchanger, a third temperature measurement unit for measuring the indoor temperature, a fourth temperature measurement unit for measuring the outdoor temperature, and a control device. The control device has an operation determination unit, a first comparison unit for comparing the outdoor temperature with the temperature of the outdoor heat exchanger in the case of a cooling operation, and a first determination unit for determining the state of each device when the temperature of the outdoor heat exchanger is lower than the outdoor temperature.

Description

air conditioner

[0001] This application claims priority to Japanese Patent Application No. 2023-166722, filed on September 28, 2023, the contents of which are incorporated herein by reference.

[0002] Air conditioners that use a refrigeration cycle can experience abnormalities such as gas low (insufficient refrigerant), blocked control valves, and faulty four-way valve switching. Continuing operation under these conditions is known to cause compressor failure.

[0003] A known technology for determining the type of abnormality in a refrigeration cycle is described in Patent Document 1. The device disclosed in Patent Document 1 obtains the temperature of either the indoor heat exchanger or the outdoor heat exchanger as an index, and is capable of determining various abnormal states based on this index.

[0004] Japanese Patent Application Laid-Open No. 2003-090582

[0005] However, when the temperature of only one of the indoor and outdoor heat exchangers is used as an indicator, the accuracy of abnormality detection may be compromised. For example, there remains a drawback in that it is not possible to distinguish between a blocked control valve in a gas pipe (a pipe through which a gas-phase refrigerant flows) and a blocked control valve in a liquid pipe (a pipe through which a liquid-phase refrigerant flows).

[0006] The present disclosure provides an air conditioner that is capable of more precisely determining the type of abnormal state.

[0007] An air conditioner according to the present disclosure includes an indoor heat exchanger, an outdoor heat exchanger, a gas pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a gas-phase refrigerant flows, a compressor arranged on the gas pipe, a liquid pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a liquid-phase or two-phase gas-liquid refrigerant flows and which forms a circulation circuit together with the gas pipe, an expansion valve arranged on the liquid pipe, and a four-way valve that switches the flow direction of the refrigerant between a cooling operation and a heating operation, and the air conditioner according to the present disclosure includes a first operating valve arranged on the gas pipe between the compressor and the indoor heat exchanger, a second operating valve arranged on the liquid pipe between the expansion valve and the indoor heat exchanger, a first temperature measuring unit that measures the temperature of the indoor heat exchanger, and a temperature measuring unit that measures the temperature of the outdoor heat exchanger. the control device further comprises a second temperature measurement unit that measures the temperature of the indoor heat exchanger, a third temperature measurement unit that measures the indoor temperature, a fourth temperature measurement unit that measures the outdoor temperature, and a control device, wherein the control device has an operation determination unit that determines whether the air conditioning device is in the cooling operation or the heating operation, a first comparison unit that, in the cooling operation, compares the temperature of the outdoor heat exchanger with the outdoor temperature, and a first determination unit that determines the state of each device when the temperature of the outdoor heat exchanger is lower than the outdoor temperature, and the first determination unit determines that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger is equal to or higher than a predetermined first threshold, and determines that the first operating valve and the second operating valve are in a blocked state when the temperature of the indoor heat exchanger is lower than the first threshold.

[0008] An air conditioner according to the present disclosure includes an indoor heat exchanger, an outdoor heat exchanger, a gas pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a gas-phase refrigerant flows, a compressor disposed on the gas pipe, a liquid pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a liquid-phase refrigerant flows and which forms a circulation circuit together with the gas pipe, an expansion valve disposed on the liquid pipe, and a four-way valve that switches the flow direction of the refrigerant between a cooling operation and a heating operation, and the air conditioner according to the present disclosure includes a first operating valve disposed on the gas pipe between the compressor and the indoor heat exchanger, a second operating valve disposed on the liquid pipe between the expansion valve and the indoor heat exchanger, and a valve that controls the flow direction of the refrigerant between the indoor heat exchanger and the outdoor heat exchanger. the control device further comprises a first temperature measurement unit that measures the temperature of the outdoor heat exchanger, a second temperature measurement unit that measures the temperature of the outdoor heat exchanger, a third temperature measurement unit that measures the temperature inside the room, a fourth temperature measurement unit that measures the temperature outside the room, and a control device, wherein the control device has an operation determination unit that determines whether the air conditioning device is in the cooling operation or the heating operation, a first comparison unit that, when in the heating operation, compares the temperature of the outdoor heat exchanger with the temperature outside the room, and a first determination unit that determines the state of each device when the temperature of the outdoor heat exchanger is higher than the temperature outside the room, and the first determination unit determines that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger is lower than a predetermined first threshold value.

[0009] According to the present disclosure, it is possible to provide an air conditioner that is capable of determining the type of abnormal state in more detail.

[0010] FIG. 1 is a circuit diagram of an air conditioner according to an embodiment of the present disclosure, illustrating a state during cooling operation. FIG. 2 is a circuit diagram of an air conditioner according to an embodiment of the present disclosure, illustrating a state during heating operation. FIG. 3 is a table illustrating the relationship between various indicators and abnormal states in an air conditioner according to an embodiment of the present disclosure. FIG. 4 is a functional block diagram of a control device according to an embodiment of the present disclosure. FIG. 5 is a control flow during cooling operation of a control device according to an embodiment of the present disclosure. FIG. 6 is another control flow during cooling operation and heating operation of a control device according to an embodiment of the present disclosure. FIG. 7 is a control flow during heating operation of a control device according to an embodiment of the present disclosure. FIG. 8 is a hardware configuration diagram of a control device according to an embodiment of the present disclosure.

[0011] (Configuration of Air Conditioner 1) An air conditioner 1 according to an embodiment of the present disclosure will now be described with reference to Fig. 1 to Fig. 8. As shown in Fig. 1, the air conditioner 1 includes a refrigeration cycle circuit 10, a first operating valve 20, a second operating valve 30, a first temperature measuring unit 41, a second temperature measuring unit 42, a third temperature measuring unit 43, a fourth temperature measuring unit 44, and a control device 50.

[0012] (Refrigeration Cycle Circuit 10) The refrigeration cycle circuit 10 includes an indoor heat exchanger 11, an outdoor heat exchanger 12, a gas pipe 13, a compressor 14, a liquid pipe 15, an expansion valve 16, and a four-way valve (not shown).

[0013] The indoor heat exchanger 11 exchanges heat between the indoor air and the refrigerant. The indoor heat exchanger 11 is, for example, a fin-and-tube or plate-type heat exchanger, and the refrigerant flows through it. Although not shown, it is desirable that the indoor heat exchanger 11 be equipped with a fan that compresses and sends air into the room.

[0014] The outdoor heat exchanger 12 exchanges heat between the outdoor air and the refrigerant. Like the indoor heat exchanger 11, the outdoor heat exchanger 12 is a heat exchanger of, for example, a fin-and-tube type or a plate type, and a refrigerant flows through the outdoor heat exchanger 12. Although not shown, the outdoor heat exchanger 12 is preferably provided with a fan that pressurizes and sends air to the outside of the room.

[0015] (Gas Pipe 13 and Compressor 14) The gas pipe 13 is a pipe connecting the indoor heat exchanger 11 and the outdoor heat exchanger 12, and a gas-phase refrigerant flows inside. A compressor 14 is provided on the gas pipe 13. The compressor 14 is, for example, a scroll-type or rotary-type rotary machine, and compresses the gas-phase refrigerant that flows in from the inlet side, raising the pressure to a predetermined level, and then discharges the refrigerant into the gas pipe 13.

[0016] (Liquid Pipe 15 and Expansion Valve 16) The liquid pipe 15 is a pipe connecting the indoor heat exchanger 11 and the outdoor heat exchanger 12, and a liquid-phase or two-phase gas-liquid refrigerant flows through it. The liquid pipe 15 forms a circulation circuit together with the gas pipe 13. That is, both ends of the liquid pipe 15 are connected to ends of the indoor heat exchanger 11 and the outdoor heat exchanger 12 that are different from the ends to which the gas pipe 13 is connected. An expansion valve 16 is provided on the liquid pipe 15. The expansion valve 16 is, for example, an electromagnetic expansion valve 16, and has the function of expanding the refrigerant flowing through the liquid pipe 15 to reduce its pressure.

[0017] Although not shown, the four-way valve switches the flow direction of the refrigerant in the gas pipe 13 and the liquid pipe 15 between cooling operation and heating operation. During cooling operation, as shown in Fig. 1, the refrigerant flows through the compressor 14, the outdoor heat exchanger 12, the expansion valve 16, and the indoor heat exchanger 11 in that order. On the other hand, during heating operation, as shown in Fig. 2, the refrigerant flows through the compressor 14, the indoor heat exchanger 11, the expansion valve 16, and the outdoor heat exchanger 12 in that order.

[0018] (Operation of Refrigeration Cycle Circuit 10) Next, the operation of the refrigeration cycle circuit 10 during cooling operation will be described. During cooling operation, high-temperature, high-pressure gas-phase refrigerant discharged from the compressor 14 flows into the outdoor heat exchanger 12. In the outdoor heat exchanger 12, the refrigerant exchanges heat with outdoor air, becoming a high-temperature, high-pressure liquid-phase refrigerant. This refrigerant then passes through the expansion valve 16, where it is reduced in pressure, becoming a low-temperature, low-pressure, two-phase liquid-phase refrigerant. This refrigerant then flows into the indoor exchanger and exchanges heat with indoor air. That is, the low-temperature refrigerant exchanges heat with the high-temperature indoor air, lowering the indoor air temperature. Meanwhile, the temperature of the refrigerant rises, becoming a low-temperature, low-pressure gas-phase refrigerant. This refrigerant flows back into the compressor 14, and the above cycle continues.

[0019] On the other hand, during heating operation, the high-temperature, high-pressure gas-phase refrigerant discharged from the compressor 14 flows into the indoor heat exchanger 11. In the indoor heat exchanger 11, the refrigerant exchanges heat with the indoor air, becoming a high-temperature, high-pressure liquid-phase refrigerant. This refrigerant then passes through the expansion valve 16, where it is reduced in pressure, becoming a low-temperature, low-pressure two-phase gas-liquid refrigerant. This refrigerant then flows into the outdoor exchanger and exchanges heat with the outdoor air. In other words, the low-temperature refrigerant exchanges heat with the outdoor air, generating a low-temperature, low-pressure gas-phase refrigerant. This refrigerant flows back into the compressor 14, and the above cycle continues.

[0020] (First Operation Valve 20, Second Operation Valve 30) The first operation valve 20 is a valve that switches the flow state of the refrigerant in the gas pipe 13. The second operation valve 30 is a valve that switches the flow state of the refrigerant in the liquid pipe 15. Electromagnetic on-off valves are preferably used as these valves.

[0021] (First temperature measurement unit 41 to fourth temperature measurement unit 44) The first temperature measurement unit 41 is a temperature sensor that measures the temperature of the indoor heat exchanger 11. The second temperature measurement unit 42 is a temperature sensor that measures the temperature of the outdoor heat exchanger 12. These sensors directly measure the temperature of the pipes, fins, etc. in the heat exchanger, rather than the temperature of the refrigerant in the heat exchanger. The third temperature measurement unit 43 measures the indoor temperature, and the fourth temperature measurement unit 44 measures the outdoor temperature. The first temperature measurement unit 41 to fourth temperature measurement unit 44 are each electrically connected to the control device 50, which will be described later, and transmit their respective measurement results to the control device 50 as electrical signals.

[0022] (Control device 50) The control device 50 detects and determines abnormal states of various devices based on the results of measurements by the above-mentioned first temperature measurement unit 41 to fourth temperature measurement unit 44. As shown in Fig. 4, the control device 50 has an operation determination unit 51, a first comparison unit 52, a first determination unit 53, a second comparison unit 54, a second determination unit 55, a third determination unit 56, a fourth determination unit 57, and a memory unit 58. The operation of each functional block will be described below with reference to the flowcharts shown in Figs. 5 to 7.

[0023] (Operation of Each Functional Block During Cooling Operation) The operation determination unit 51 determines whether the air conditioner 1 is in cooling operation or heating operation (step S11). First, the operation of each functional block during cooling operation will be described. During cooling operation, the first comparison unit 52 compares the temperature of the outdoor heat exchanger 12 with the outdoor temperature (step S12). The first determination unit 53 determines the state of each device when it is determined that the temperature of the outdoor heat exchanger 12 is lower than the outdoor temperature (step S13). Specifically, the first determination unit 53 determines that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger 11 is equal to or higher than a predetermined first threshold, and determines that the first operating valve 20 and the second operating valve 30 are in a closed state when the temperature of the indoor heat exchanger 11 is lower than the first threshold.

[0024] In other words, the type of abnormal state is determined based on the relationship between the measured temperature of each part and the state of each device shown in Figure 3. The states [1] to [5] in Figure 3 correspond to the numbers [1] to [5] in Figures 5 to 7.

[0025] If the first comparison unit 52 determines that the temperature of the outdoor heat exchanger 12 is higher than the outdoor temperature, the second comparison unit 54 compares the temperature of the indoor heat exchanger 11 with the indoor temperature (step S14). If the first comparison unit 52 determines that the temperature of the indoor heat exchanger 11 is higher than the indoor temperature in step S14, the second determination unit 55 determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined second threshold value (step S15). Specifically, if the temperature of the indoor heat exchanger 11 is higher than the second threshold value, the second determination unit 55 determines that the first operating valve 20 is in a closed state, and if the temperature of the indoor heat exchanger 11 is lower than the second threshold value, the second determination unit 55 determines that the first operating valve 20 and the second operating valve 30 are in a closed state.

[0026] On the other hand, if the first comparison unit 52 determines that the temperature of the outdoor heat exchanger 12 is lower than the outdoor temperature, the third determination unit 56 determines whether an abnormality exists (step S16). Specifically, the third determination unit 56 determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined third threshold value and a fourth threshold value that is higher than the third threshold value. More specifically, if the temperature of the indoor heat exchanger 11 is lower than the third threshold value, the third determination unit 56 determines that the second operating valve 30 is in a closed state or in a normal operating state. If the temperature of the indoor heat exchanger 11 is higher than the third threshold value and lower than the fourth threshold value, the third determination unit 56 determines that the refrigerant charge amount is reduced. Furthermore, if the temperature of the indoor heat exchanger 11 is higher than the fourth threshold value, the third determination unit 56 determines that the first operating valve 20 and the second operating valve 30 are in a closed state.

[0027] If the third determination unit 56 determines that the temperature of the indoor heat exchanger 11 is lower than the third threshold, a further determination is made by the fourth determination unit 57. As shown in Fig. 6 , the fourth determination unit 57 operates the compressor 14 for a predetermined time while the rotation speed is higher than a predetermined rotation speed threshold (step S21). Thereafter, if the temperature of the indoor heat exchanger 11 is higher than a predetermined fifth threshold, the fourth determination unit 57 determines that the second operating valve 30 is in a closed state (step S22). In other words, it is determined whether the system is in a normal operating state or whether the second operating valve 30 is in a closed state.

[0028] (Operation of Each Functional Block During Heating Operation) On the other hand, during heating operation, each functional block operates as shown in Fig. 7 . That is, even when it is determined in step S31 that the system is in heating operation, the first comparison unit 52 compares the temperature of the outdoor heat exchanger 12 with the outdoor temperature (step S32). The first determination unit 53 determines the state of each device when it is determined that the temperature of the outdoor heat exchanger 12 is higher than the outdoor temperature. Specifically, when the temperature of the indoor heat exchanger 11 is lower than a predetermined first threshold, the first determination unit 53 determines that a switching malfunction of the four-way valve has occurred (step S33).

[0029] On the other hand, if the first determination unit 53 determines that the temperature of the outdoor heat exchanger 12 is lower than the outdoor temperature, the second comparison unit 54 compares the temperature of the indoor heat exchanger 11 with the indoor temperature (step S34). If it is determined in step S34 that the temperature of the indoor heat exchanger 11 is lower than the indoor temperature, the second determination unit 55 determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined second threshold. Specifically, the second determination unit 55 determines that the first operating valve 20 and the second operating valve 30 are in a closed state if the temperature of the indoor heat exchanger 11 is higher than the second threshold, and determines that the first operating valve 20 is in a closed state if the temperature of the indoor heat exchanger 11 is equal to or lower than the second threshold (step S35).

[0030] Furthermore, if the second comparison unit 54 determines that the temperature of the indoor heat exchanger 11 is higher than the room temperature, the third determination unit 56 determines the state of each device. Specifically, the third determination unit 56 compares the temperature of the indoor heat exchanger 11 with a predetermined third threshold value and a fourth threshold value that is higher than the third threshold value. If the temperature of the indoor heat exchanger 11 is lower than the third threshold value, the third determination unit 56 determines that the first operating valve 20 and the second operating valve 30 are in a closed state. If the temperature of the indoor heat exchanger 11 is higher than the third threshold value and lower than the fourth threshold value, the third determination unit 56 determines that the refrigerant charge amount is decreasing. If the temperature of the indoor heat exchanger 11 is higher than the fourth threshold value, the third determination unit 56 determines that the second operating valve 30 is in a closed state or in a normal operating state (step S36).

[0031] If the third determination unit 56 determines that the temperature of the indoor heat exchanger 11 is higher than the third threshold, a further determination is made by the fourth determination unit 57. As shown in Fig. 6 , if the fourth determination unit 57 determines that the temperature of the indoor heat exchanger 11 is higher than the fourth threshold, the fourth determination unit 57 operates the compressor 14 for a predetermined time period with the rotation speed higher than a predetermined rotation speed threshold (step S21). Thereafter, if the temperature of the outdoor heat exchanger 12 is lower than a predetermined sixth threshold, the fourth determination unit 57 determines that the second operating valve 30 is in a closed state (step S22).

[0032] (Effects) Conventional equipment typically acquires the temperature of either the indoor heat exchanger 11 or the outdoor heat exchanger 12 as an index and determines various abnormal conditions based on this index. However, this method can impair the accuracy of determining abnormal conditions. For example, this method has the drawback of being unable to distinguish between a blocked control valve in the gas pipe 13 (the pipe through which the gas-phase refrigerant flows) and a blocked control valve in the liquid pipe 15 (the pipe through which the liquid-phase refrigerant flows). Therefore, the present embodiment employs the above-described configurations.

[0033] With the above configuration, the first discrimination unit 53 can discriminate between a four-way valve switching failure and blockage of the first operating valve 20 and the second operating valve 30 based on the temperatures of the indoor heat exchanger 11, the outdoor heat exchanger 12, the indoor temperature, and the outdoor temperature. That is, during cooling operation, if the four-way valve switching failure occurs, the refrigerant flow direction is reversed from the predetermined direction, causing the temperature of the indoor heat exchanger 11 to rise and the temperature of the outdoor heat exchanger 12 to fall. On the other hand, if the four-way valve switching is normal and the first operating valve 20 and the second operating valve 30 are blocked, the temperatures of the indoor heat exchanger 11 and the outdoor heat exchanger 12 do not change. Based on these temperature indicators, it is possible to more precisely discriminate between abnormal conditions. Therefore, if an abnormality occurs, appropriate measures can be taken immediately to restore the system. As a result, the air conditioner 1 can be operated more stably over a long period of time.

[0034] According to the above configuration, the second determination unit 55 can determine whether the first operating valve 20 is in a closed state or whether the first operating valve 20 and the second operating valve 30 are in a closed state based on the temperature of the indoor heat exchanger 11 and the room temperature. That is, during cooling operation, when the first operating valve 20 is in a closed state, refrigerant present in the section between the first operating valve 20 and the inlet of the compressor 14 flows into the indoor heat exchanger 11 and the outdoor heat exchanger 12, but because the amount is small, the pressure increase is small. Therefore, the temperature change of the indoor heat exchanger 11 and the outdoor heat exchanger 12 is small. On the other hand, when the first operating valve 20 and the second operating valve 30 are in a closed state, communication between the indoor heat exchanger 11 and the outdoor heat exchanger 12 is blocked, and the temperature change of the indoor heat exchanger 11 is extremely small. Furthermore, although the refrigerant present in the section between the first operating valve 20 and the inlet of the compressor 14 flows into the indoor heat exchanger 11 and the outdoor heat exchanger 12, the amount is small, so the pressure rise in the outdoor heat exchanger 12 is small. Therefore, the temperature change in the outdoor heat exchanger 12 is small. Based on these temperature indicators, it is possible to more precisely determine an abnormal state. Therefore, if an abnormality occurs, appropriate measures can be taken immediately to restore the system. As a result, it is possible to operate the air conditioning system 1 more stably over a long period of time.

[0035] With the above configuration, the third determination unit 56 can determine whether the second control valve 30 is in a closed state or in normal operation, whether the refrigerant charge level is low, and whether the first control valve 20 and the second control valve 30 are in a closed state, based on the temperature of the indoor heat exchanger 11 and the room temperature. That is, when the refrigerant charge level is low during cooling operation, the refrigerant flow direction is the same as during normal operation, resulting in small temperature changes in the indoor heat exchanger 11 and the outdoor heat exchanger 12. Furthermore, when the second control valve 30 is in a closed state, the pressure in the indoor heat exchanger 11 decreases, thereby decreasing the temperature of the indoor heat exchanger 11. On the other hand, the pressure in the outdoor heat exchanger 12 increases, thereby increasing the temperature of the outdoor heat exchanger 12. Based on these temperature indicators, it is possible to more precisely determine an abnormal state. Therefore, appropriate measures can be taken immediately to restore operation when an abnormality occurs. As a result, the air conditioner 1 can be operated more stably over a long period of time.

[0036] According to the above configuration, when the third determination unit 56 determines that the temperature of the indoor heat exchanger 11 is lower than the third threshold, the compressor 14 is operated at a predetermined rotation speed for a certain period of time, and then the fourth determination unit 57 determines whether the second operating valve 30 is in a closed state or in a normal operating state based on a comparison with a further threshold. That is, when the second operating valve 30 is in a closed state during cooling operation, the pressure in the indoor heat exchanger 11 decreases, thereby decreasing the temperature of the indoor heat exchanger 11. On the other hand, the pressure in the outdoor heat exchanger 12 increases, thereby increasing the temperature of the outdoor heat exchanger 12. Based on these temperature indicators, it is possible to more precisely determine an abnormal state. Therefore, when an abnormality occurs, appropriate measures can be taken immediately to restore the system. As a result, the air conditioner 1 can be operated more stably over a long period of time.

[0037] With the above configuration, the first determination unit 53 can determine whether the four-way valve is malfunctioning based on the temperatures of the indoor heat exchanger 11, the outdoor heat exchanger 12, the indoor temperature, and the outdoor temperature. That is, during heating operation, if the four-way valve is malfunctioning, the refrigerant flow direction is reversed from the predetermined direction, causing the temperature of the indoor heat exchanger 11 to drop and the temperature of the outdoor heat exchanger 12 to rise. Based on these temperature indicators, it becomes possible to more precisely determine whether an abnormality exists. Therefore, if an abnormality occurs, appropriate measures can be taken immediately to restore the system. As a result, the air conditioner 1 can be operated more stably over a long period of time.

[0038] With the above configuration, the second determination unit 55 can determine whether the first operating valve 20 is in a closed state or whether the first operating valve 20 and the second operating valve 30 are in a closed state based on the temperature of the indoor heat exchanger 11 and the room temperature. That is, during heating operation, when the first operating valve 20 is in a closed state, all refrigerant flows into the section between the first operating valve 20 and the inlet of the compressor 14, thereby reducing the pressure in the indoor heat exchanger 11 and the outdoor heat exchanger 12. Consequently, the temperatures of the indoor heat exchanger 11 and the outdoor heat exchanger 12 also decrease. On the other hand, when the first operating valve 20 and the second operating valve 30 are in a closed state, communication between the indoor heat exchanger 11 and the outdoor heat exchanger 12 is blocked, resulting in minimal change in the temperature of the outdoor heat exchanger 12. Furthermore, because all refrigerant flows into the section between the first operating valve 20 and the inlet of the compressor 14, the pressure in the outdoor heat exchanger 12 decreases. Consequently, the temperature of the outdoor heat exchanger 12 also decreases. Based on these temperature indices, it becomes possible to more precisely determine whether an abnormality has occurred. Therefore, if an abnormality occurs, appropriate measures can be taken immediately to restore the normal operation. As a result, it becomes possible to operate the air conditioner 1 more stably over a long period of time.

[0039] With the above configuration, the third determination unit 56 can determine whether the second control valve 30 is in a closed state or in normal operation, whether the refrigerant charge level is low, and whether the first control valve 20 and the second control valve 30 are in a closed state, based on the temperature of the indoor heat exchanger 11 and the room temperature. That is, when the refrigerant charge level is low during heating operation, the refrigerant flow direction is the same as during normal operation, resulting in small temperature changes in the indoor heat exchanger 11 and the outdoor heat exchanger 12. Furthermore, when the second control valve 30 is in a closed state, the pressure in the indoor heat exchanger 11 increases, causing the temperature of the indoor heat exchanger 11 to also increase. On the other hand, the pressure in the outdoor heat exchanger 12 decreases, causing the temperature of the outdoor heat exchanger 12 to decrease. Based on these temperature indicators, abnormal conditions can be more precisely determined. Therefore, appropriate measures can be taken immediately to restore normal operation when an abnormality occurs. As a result, the air conditioner 1 can be operated more stably over a long period of time.

[0040] According to the above configuration, when the third determination unit 56 determines that the temperature of the indoor heat exchanger 11 is higher than the fourth threshold, the compressor 14 is operated at a predetermined rotation speed for a certain period of time, and then the fourth determination unit 57 determines whether the second operating valve 30 is in a closed state or in a normal operating state based on a comparison with a further threshold. That is, when the second operating valve 30 is in a closed state during heating operation, the pressure in the indoor heat exchanger 11 increases, causing the temperature of the indoor heat exchanger 11 to also increase. On the other hand, the pressure in the outdoor heat exchanger 12 decreases, causing the temperature of the outdoor heat exchanger 12 to also decrease. Based on these temperature indicators, an abnormal state can be more precisely determined. Therefore, when an abnormality occurs, appropriate measures can be taken immediately to restore the system. As a result, the air conditioner 1 can be operated more stably over a long period of time.

[0041] (Other Embodiments) While the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present disclosure. For example, the configuration of the refrigeration cycle circuit 10 is merely an example, and a configuration including other auxiliary devices such as a receiver (not shown) is also possible. In other words, the above configurations can be applied to any device that uses a refrigeration cycle. In other words, the above configurations can accurately identify abnormal conditions while maintaining high versatility regardless of the type of refrigeration cycle device or the type of auxiliary devices.

[0042] It should be noted that the order of the processes performed by the control device 50 in the embodiment of the present disclosure may be changed as long as the processes are performed appropriately.

[0043] The storage unit 58 and other storage devices in the embodiments of the present disclosure may be provided anywhere within a range where appropriate information can be transmitted and received. Furthermore, there may be multiple storage units 58 and other storage devices within a range where appropriate information can be transmitted and received, and data may be stored in a distributed manner.

[0044] The above-described processing steps performed by the control device 50 are stored in the form of a program on a recording medium that can be read by the computer 200, and the above processing is performed by the computer 200 reading and executing this program. A specific example of the computer 200 is shown below.

[0045] 8, the computer 200 includes a CPU 101, a main memory 102, a storage 103, and an interface 104. For example, the above-described control device 50 is implemented in the computer 200. The operations of the above-described processing units are stored in the storage 103 in the form of a program. The CPU 101 reads the program from the storage 103, loads it into the main memory 102, and executes the above-described processing in accordance with the program. The CPU 101 also allocates a storage area in the main memory 102 corresponding to the above-described storage unit 58 in accordance with the program.

[0046] Examples of storage 103 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 103 may be an internal medium directly connected to the bus of computer 200, or an external medium connected to computer 200 via interface 104 or a communication line. Furthermore, when this program is distributed to computer 200 via a communication line, computer 200 that receives the program may load the program into main memory 102 and execute the above-described processing. Storage 103 is a non-transitory tangible storage medium.

[0047] The program may also implement some of the functions described above. Furthermore, the program may be a file that can implement the functions described above in combination with a program already recorded on computer 200, that is, a so-called differential file (differential program).

[0048] In addition to or instead of the above configuration, a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device), an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), or a processing device similar thereto may be provided. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions realized by a processor may be realized by the integrated circuit.

[0049] <Additional Notes> The air conditioner 1 described in each embodiment can be understood, for example, as follows.

[0050] (1) An air conditioner 1 according to a first aspect includes an indoor heat exchanger 11, an outdoor heat exchanger 12, a gas pipe 13 connecting the indoor heat exchanger 11 and the outdoor heat exchanger 12 and through which a gas-phase refrigerant flows, a compressor 14 arranged on the gas pipe 13, a liquid pipe 15 connecting the indoor heat exchanger 11 and the outdoor heat exchanger 12 and through which a liquid-phase or two-phase gas-liquid refrigerant flows and which forms a circulation circuit together with the gas pipe 13, an expansion valve 16 arranged on the liquid pipe 15, and a four-way valve that switches the flow direction of the refrigerant between cooling operation and heating operation. The air conditioner 1 includes a first operating valve 20 arranged on the gas pipe 13 between the compressor 14 and the indoor heat exchanger 11, a second operating valve 30 arranged on the liquid pipe 15 between the expansion valve 16 and the indoor heat exchanger 11, and a first temperature measuring unit 41 that measures the temperature of the indoor heat exchanger 11. The air conditioning system further includes a second temperature measurement unit 42 that measures the temperature of the outdoor heat exchanger 12, a third temperature measurement unit 43 that measures the temperature inside the room, a fourth temperature measurement unit 44 that measures the temperature outside the room, and a control device 50. The control device 50 has an operation determination unit 51 that determines whether the air conditioning system 1 is in the cooling operation or the heating operation, a first comparison unit 52 that compares the temperature of the outdoor heat exchanger 12 with the outdoor temperature in the cooling operation, and a first determination unit 53 that determines the state of each device when the temperature of the outdoor heat exchanger 12 is lower than the outdoor temperature. The first determination unit 53 determines that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger 11 is equal to or higher than a predetermined first threshold, and determines that the first operating valve 20 and the second operating valve 30 are in a blocked state when the temperature of the indoor heat exchanger 11 is lower than the first threshold.

[0051] According to the above configuration, the first discrimination unit 53 can discriminate between a switching failure of the four-way valve and blockage of the first operating valve 20 and the second operating valve 30 based on the temperature of the indoor heat exchanger 11, the temperature of the outdoor heat exchanger 12, the indoor temperature, and the outdoor temperature.

[0052] (2) The air conditioning device 1 according to a second aspect is the air conditioning device 1 of (1), wherein the control device 50 further includes a second comparison unit 54 that compares the temperature of the indoor heat exchanger 11 with the temperature inside the room when the first comparison unit 52 determines that the temperature of the outdoor heat exchanger 12 is higher than the outdoor temperature, and a second determination unit 55 that determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined second threshold value when the temperature of the indoor heat exchanger 11 is higher than the temperature inside the room, and the second determination unit 55 determines that the first operating valve 20 is in a blocked state when the temperature of the indoor heat exchanger 11 is higher than the second threshold value, and determines that the first operating valve 20 and the second operating valve 30 are in a blocked state when the temperature of the indoor heat exchanger 11 is lower than the second threshold value.

[0053] According to the above configuration, the second discrimination unit 55 can determine whether the first operating valve 20 is in a blocked state, or whether the first operating valve 20 and the second operating valve 30 are in a blocked state, based on the temperature of the indoor heat exchanger 11 and the temperature inside the room.

[0054] (3) An air conditioning device 1 according to a third aspect is the air conditioning device 1 of (2), wherein the control device 50 further includes a third determination unit 56 that, when the second comparison unit 54 determines that the temperature of the indoor heat exchanger 11 is lower than the temperature inside the room, determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined third threshold value and a fourth threshold value that is higher than the third threshold value, and the third determination unit 56 determines that the second operating valve 30 is in a blocked state or in a normal operating state when the temperature of the indoor heat exchanger 11 is higher than the third threshold value and lower than the fourth threshold value, determines that the amount of refrigerant charged is decreasing, and determines that the first operating valve 20 and the second operating valve 30 are in a blocked state when the temperature of the indoor heat exchanger 11 is higher than the fourth threshold value.

[0055] According to the above configuration, based on the temperature of the indoor heat exchanger 11 and the temperature inside the room, the third discrimination unit 56 can determine whether the second operating valve 30 is in a blocked state or in a normal operating state, whether the amount of refrigerant charged is decreasing, and whether the first operating valve 20 and the second operating valve 30 are in a blocked state.

[0056] (4) The air conditioning device 1 according to a fourth aspect is the air conditioning device 1 of (3), wherein the control device 50 further includes a fourth determination unit 57 that determines whether the second operating valve 30 is in a blocked state or in a normal operating state when the third determination unit 56 determines that the temperature of the indoor heat exchanger 11 is lower than the third threshold value, and the fourth determination unit 57 operates the compressor 14 for a predetermined time period in a state where the rotation speed is higher than a predetermined rotation speed threshold value, and determines that the second operating valve 30 is in a blocked state when the temperature of the indoor heat exchanger 11 is higher than a predetermined fifth threshold value.

[0057] According to the above configuration, when the third discrimination unit 56 determines that the temperature of the indoor heat exchanger 11 is lower than the third threshold value, the compressor 14 is operated at a predetermined rotation speed for a certain period of time, and then the fourth discrimination unit 57 can determine whether the second operating valve 30 is in a blocked state or in a normal operating state based on a comparison with a further threshold value.

[0058] (5) An air conditioner 1 according to a fifth aspect is an air conditioner 1 including an indoor heat exchanger 11, an outdoor heat exchanger 12, a gas pipe 13 connecting the indoor heat exchanger 11 and the outdoor heat exchanger 12 and through which a gas phase refrigerant flows, a compressor 14 arranged on the gas pipe 13, a liquid pipe 15 connecting the indoor heat exchanger 11 and the outdoor heat exchanger 12 and through which a liquid phase refrigerant flows and which forms a circulation circuit together with the gas pipe 13, an expansion valve 16 arranged on the liquid pipe 15, and a four-way valve that switches the flow direction of the refrigerant between cooling operation and heating operation, and further including a first operating valve 20 arranged on the gas pipe 13 between the compressor 14 and the indoor heat exchanger 11, and a second operating valve 30 arranged on the liquid pipe 15 between the expansion valve 16 and the indoor heat exchanger 11. The air conditioning system further includes a first temperature measuring unit 41 that measures the temperature of the indoor heat exchanger 11, a second temperature measuring unit 42 that measures the temperature of the outdoor heat exchanger 12, a third temperature measuring unit 43 that measures the indoor temperature, a fourth temperature measuring unit 44 that measures the outdoor temperature, and a control device 50. The control device 50 has an operation determination unit 51 that determines whether the air conditioning system 1 is in the cooling operation or the heating operation, a first comparison unit 52 that, in the heating operation, compares the temperature of the outdoor heat exchanger 12 with the outdoor temperature, and a first determination unit 53 that determines the state of each device when the temperature of the outdoor heat exchanger 12 is higher than the outdoor temperature. The first determination unit 53 determines that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger 11 is lower than a predetermined first threshold value.

[0059] According to the above configuration, the first determination unit 53 can determine whether the four-way valve is switching properly based on the temperature of the indoor heat exchanger 11, the temperature of the outdoor heat exchanger 12, the indoor temperature, and the outdoor temperature.

[0060] (6) The air conditioning device 1 according to a sixth aspect is the air conditioning device 1 of (5), wherein the control device 50 further includes a second comparison unit 54 that compares the temperature of the indoor heat exchanger 11 with the temperature inside the room when the first comparison unit 52 determines that the temperature of the outdoor heat exchanger 12 is lower than the outdoor temperature, and a second determination unit 55 that determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined second threshold value when the temperature of the indoor heat exchanger 11 is lower than the indoor temperature, and the second determination unit 55 determines that the first operating valve 20 and the second operating valve 30 are in a blocked state when the temperature of the indoor heat exchanger 11 is higher than the second threshold value, and determines that the first operating valve 20 is in a blocked state when the temperature of the indoor heat exchanger 11 is equal to or lower than the second threshold value.

[0061] According to the above configuration, the second discrimination unit 55 can determine whether the first operating valve 20 is in a blocked state, or whether the first operating valve 20 and the second operating valve 30 are in a blocked state, based on the temperature of the indoor heat exchanger 11 and the temperature inside the room.

[0062] (7) The air conditioning device 1 according to a seventh aspect is the air conditioning device 1 of (6), wherein the control device 50 further has a third determination unit 56 that, when the second comparison unit 54 determines that the temperature of the indoor heat exchanger 11 is higher than the temperature inside the room, determines the state of each device by comparing the temperature of the indoor heat exchanger 11 with a predetermined third threshold value and a fourth threshold value that is higher than the third threshold value, and the third determination unit 56 determines that the first operating valve 20 and the second operating valve 30 are in a blocked state when the temperature of the indoor heat exchanger 11 is lower than the third threshold value, determines that the refrigerant charge amount is decreasing when the temperature of the indoor heat exchanger 11 is higher than the third threshold value and lower than the fourth threshold value, and determines that the second operating valve 30 is in a blocked state or in a normal operating state when the temperature of the indoor heat exchanger 11 is higher than the fourth threshold value.

[0063] According to the above configuration, based on the temperature of the indoor heat exchanger 11 and the temperature inside the room, the third discrimination unit 56 can determine whether the second operating valve 30 is in a blocked state or in a normal operating state, whether the amount of refrigerant charged is decreasing, and whether the first operating valve 20 and the second operating valve 30 are in a blocked state.

[0064] (8) An air conditioning device 1 according to an eighth aspect is the air conditioning device 1 of (7), wherein the control device 50 further includes a fourth determination unit 57 that determines whether the second operating valve 30 is in a blocked state or in a normal operating state when the third determination unit 56 determines that the temperature of the indoor heat exchanger 11 is higher than the fourth threshold value, and the fourth determination unit 57 operates the compressor 14 for a predetermined time period in a state where the rotation speed is higher than a predetermined rotation speed threshold value, and determines that the second operating valve 30 is in a blocked state when the temperature of the outdoor heat exchanger 12 is lower than a predetermined sixth threshold value.

[0065] According to the above configuration, when the third discrimination unit 56 determines that the temperature of the indoor heat exchanger 11 is higher than the fourth threshold value, the compressor 14 is operated at a predetermined rotation speed for a certain period of time, and then the fourth discrimination unit 57 can determine whether the second operating valve 30 is in a blocked state or in a normal operating state based on a comparison with a further threshold value.

[0066] According to the present disclosure, it is possible to provide an air conditioner that is capable of determining the type of abnormal state in more detail.

[0067] DESCRIPTION OF SYMBOLS 1...Air conditioner 10...Refrigeration cycle circuit 11...Indoor heat exchanger 12...Outdoor heat exchanger 13...Gas pipe 14...Compressor 15...Liquid pipe 16...Expansion valve 20...First operating valve 30...Second operating valve 41...First temperature measurement unit 42...Second temperature measurement unit 43...Third temperature measurement unit 44...Fourth temperature measurement unit 50...Control device 51...Operation determination unit 52...First comparison unit 53...First determination unit 54...Second comparison unit 55...Second determination unit 56...Third determination unit 57...Fourth determination unit 58...Memory unit 101...CPU 102...Main memory 103...Storage 104...Interface 200...Computer

Claims

1. An air conditioning device comprising: an indoor heat exchanger; an outdoor heat exchanger; a gas pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a gas-phase refrigerant flows; a compressor arranged on the gas pipe; a liquid pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a liquid-phase or two-phase refrigerant flows and which forms a circulation circuit together with the gas pipe; an expansion valve provided on the liquid pipe; and a four-way valve for switching the flow direction of the refrigerant between cooling operation and heating operation, further comprising: a first operating valve provided on the gas pipe between the compressor and the indoor heat exchanger; a second operating valve provided on the liquid pipe between the expansion valve and the indoor heat exchanger; a first temperature measuring unit that measures the temperature of the indoor heat exchanger; a second temperature measuring unit that measures the temperature of the outdoor heat exchanger; a third temperature measuring unit that measures the indoor temperature; a fourth temperature measuring unit that measures the outdoor temperature; and a control device, wherein the control device further comprises: an operation discrimination unit that discriminates whether the air conditioning device is in the cooling operation or the heating operation; a first comparison unit that compares the temperature of the outdoor heat exchanger with the outdoor temperature when the air conditioning device is in the cooling operation; and a first discrimination unit that discriminates the state of each device when the temperature of the outdoor heat exchanger is lower than the outdoor temperature, wherein the first discrimination unit determines that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger is equal to or higher than a predetermined first threshold, and determines that the first operating valve and the second operating valve are in a blocked state when the temperature of the indoor heat exchanger is less than the first threshold.

2. The control device further has: a second comparison unit which compares the temperature of the indoor heat exchanger with the temperature of the room when the first comparison unit determines that the temperature of the outdoor heat exchanger is higher than the outdoor temperature; and a second discrimination unit which discriminates the state of each device by comparing the temperature of the indoor heat exchanger with a predetermined second threshold value when the temperature of the indoor heat exchanger is higher than the room temperature, wherein the second discrimination unit determines that the first operating valve is in a blocked state when the temperature of the indoor heat exchanger is higher than the second threshold value, and determines that the first operating valve and the second operating valve are in a blocked state when the temperature of the indoor heat exchanger is lower than the second threshold value. The air conditioning device described in claim 1.

3. The control device further has a third discrimination unit that, when the second comparison unit determines that the temperature of the indoor heat exchanger is lower than the temperature inside the room, discriminates the state of each device by comparing the temperature of the indoor heat exchanger with a predetermined third threshold value and a fourth threshold value that is higher than the third threshold value, and the third discrimination unit discriminates that the second operating valve is in a blocked state or in a normal operating state when the temperature of the indoor heat exchanger is lower than the third threshold value, discriminates that the amount of refrigerant charged is decreasing when the temperature of the indoor heat exchanger is higher than the third threshold value and lower than the fourth threshold value, and discriminates that the first operating valve and the second operating valve are in a blocked state when the temperature of the indoor heat exchanger is higher than the fourth threshold value.

4. The control device further has a fourth discrimination unit which discriminates whether the second operating valve is in a blocked state or in a normal operating state when the third discrimination unit determines that the temperature of the indoor heat exchanger is lower than the third threshold value, and the fourth discrimination unit operates the compressor at a rotation speed higher than a predetermined rotation speed threshold for a predetermined period of time, and discriminates that the second operating valve is in a blocked state when the temperature of the indoor heat exchanger is higher than a predetermined fifth threshold value. The air conditioning device described in claim 3.

5. An air conditioning device comprising: an indoor heat exchanger; an outdoor heat exchanger; a gas pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a gas phase refrigerant flows; a compressor arranged on the gas pipe; a liquid pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a liquid phase refrigerant flows and which forms a circulation circuit together with the gas pipe; an expansion valve provided on the liquid pipe; and a four-way valve for switching the flow direction of the refrigerant between cooling operation and heating operation, further comprising a first operating valve provided on the gas pipe between the compressor and the indoor heat exchanger; a second operating valve provided on the liquid pipe between the expansion valve and the indoor heat exchanger; a first temperature measuring unit that measures the temperature of the indoor heat exchanger; a second temperature measuring unit that measures the temperature of the outdoor heat exchanger; a third temperature measuring unit that measures the indoor temperature; a fourth temperature measuring unit that measures the outdoor temperature; and a control device, wherein the control device an operation discrimination unit that discriminates whether the air conditioning device is in the cooling operation or the heating operation; a first comparison unit that compares the temperature of the outdoor heat exchanger with the outdoor temperature when the air conditioning device is in the heating operation; and a first discrimination unit that discriminates the state of each device when the temperature of the outdoor heat exchanger is higher than the outdoor temperature, wherein the first discrimination unit discriminates that a switching failure has occurred in the four-way valve when the temperature of the indoor heat exchanger is lower than a predetermined first threshold value.

6. The control device further has: a second comparison unit which compares the temperature of the indoor heat exchanger with the temperature of the room when the first comparison unit determines that the temperature of the outdoor heat exchanger is lower than the outdoor temperature; and a second discrimination unit which discriminates the state of each device by comparing the temperature of the indoor heat exchanger with a predetermined second threshold value when the temperature of the indoor heat exchanger is lower than the room temperature, wherein the second discrimination unit discriminates that the first operating valve and the second operating valve are in a blocked state when the temperature of the indoor heat exchanger is higher than the second threshold value, and discriminates that the first operating valve is in a blocked state when the temperature of the indoor heat exchanger is equal to or lower than the second threshold value.

7. The air conditioning device described in claim 6, wherein the control device further has a third discrimination unit that, when it is determined by the second comparison unit that the temperature of the indoor heat exchanger is higher than the temperature inside the room, discriminates the state of each device by comparing the temperature of the indoor heat exchanger with a predetermined third threshold value and a fourth threshold value that is higher than the third threshold value, and the third discrimination unit discriminates that the first operating valve and the second operating valve are in a blocked state when the temperature of the indoor heat exchanger is lower than the third threshold value, discriminates that the amount of refrigerant charged is decreasing when the temperature of the indoor heat exchanger is higher than the third threshold value and lower than the fourth threshold value, and discriminates that the second operating valve is in a blocked state or in a normal operating state when the temperature of the indoor heat exchanger is higher than the fourth threshold value.

8. The control device further has a fourth discrimination unit that discriminates whether the second operating valve is in a blocked state or in a normal operating state when the third discrimination unit determines that the temperature of the indoor heat exchanger is higher than the fourth threshold value, and the fourth discrimination unit operates the compressor at a rotation speed higher than a predetermined rotation speed threshold for a predetermined period of time, and discriminates that the second operating valve is in a blocked state when the temperature of the outdoor heat exchanger is lower than a predetermined sixth threshold value.

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