Air conditioner

Abstract

An air conditioner according to an embodiment of the present disclosure comprises: a plurality of indoor units having an indoor heat exchanger; and an outdoor unit having an outdoor heat exchanger and connected to the indoor units, wherein the outdoor unit comprises: a compressor; an accumulator connected to the compressor; a supercooler for supercooling a refrigerant; a supercooling electronic expansion valve for adjusting the flow rate of the refrigerant flowing through the supercooler; a plurality of temperature sensors; a first refrigerant pipe connecting the supercooler and the accumulator to each other; a first valve provided on the first refrigerant pipe; a second refrigerant pipe connecting the supercooler and the compressor to each other; a second valve provided on the second refrigerant pipe; and a control unit for diagnosing a failure of the supercooling electronic expansion valve on the basis of temperature data measured by the plurality of temperature sensors in a state in which the first valve or the second valve is opened.

Description

air conditioner

[0001] The present disclosure relates to an air conditioner, and more specifically, to an air conditioner capable of cooling and heating operation.

[0002] An air conditioner is installed to provide a more comfortable indoor environment for humans by discharging hot and cold air into the room to regulate the indoor temperature and purify the indoor air, thereby creating a pleasant indoor environment. Generally, an air conditioner includes an indoor unit composed of a heat exchanger and installed indoors, and an outdoor unit composed of a compressor and a heat exchanger, which supplies refrigerant to the indoor unit.

[0003] The air conditioner operates in cooling or heating mode depending on the flow of the refrigerant.

[0004] During cooling operation, high-temperature, high-pressure liquid refrigerant is supplied from the outdoor unit's compressor through the outdoor unit's heat exchanger to the indoor unit; as the refrigerant expands and vaporizes in the indoor unit's heat exchanger, the temperature of the surrounding air decreases, and as the indoor unit's fan rotates, cold air is discharged into the room.

[0005] During heating operation, high-temperature, high-pressure gaseous refrigerant is supplied to the indoor unit from the outdoor unit's compressor, and air warmed by the energy released as the high-temperature, high-pressure gaseous refrigerant liquefies in the indoor unit's heat exchanger is discharged into the room according to the operation of the indoor unit's fan.

[0006] The air conditioner includes a number of valves. The air conditioner for both heating and cooling switches the direction of refrigerant flow using valves. For example, the outdoor heat exchanger is switched from the condenser to the evaporator through four-way valve switching. Additionally, the air conditioner may include a subcooler and a subcooling electronic expansion valve that controls the flow rate of the refrigerant flowing to the subcooler in order to reduce the pressure of the refrigerant and further secure the degree of subcooling of the system through heat exchange.

[0007] Korean Registered Patent No. 10-2674766 relates to a valve fault diagnosis system and a valve fault diagnosis method using the same, disclosing an artificial intelligence-based valve fault diagnosis system that uses voltage and current signal information to diagnose solenoid valve faults without installing a separate sensor. Since Korean Registered Patent No. 10-2674766 is an artificial intelligence-based valve fault system, hardware resources for learning and diagnosis are required, and it is only possible to diagnose the on / off status of the solenoid valve.

[0008] Supercooler control is performed by controlling the supercooling electronic expansion valve. If the supercooling electronic expansion valve fails, it can lead to system performance degradation and reduced energy efficiency. Therefore, a method to quickly diagnose the failure of the supercooling electronic expansion valve is required.

[0009] The problem that the present disclosure aims to solve is to provide a method for automatically diagnosing a failure of a supercooled electronic expansion valve in an air conditioning system.

[0010] Another objective of the present disclosure is to provide an air conditioner capable of rapidly detecting a failure of a supercooled electronic expansion valve, responding quickly to the occurrence of a failure, thereby maintaining stable system performance and enabling efficient operation.

[0011] Another objective of the present disclosure is to provide an air conditioner that can diagnose failures early, thereby reducing unnecessary maintenance costs and extending its lifespan.

[0012] Another objective of the present disclosure is to provide an air conditioner capable of optimizing supercooler and cycle performance through an automated diagnostic system.

[0013] The problems of the present disclosure are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0014] A fault diagnosis logic according to one embodiment of the present disclosure monitors the opening degree and temperature difference of the supercooling expansion valve according to the control state of the valves to determine the stuck state of the supercooling expansion valve.

[0015] An air conditioner according to one embodiment of the present disclosure comprises a plurality of indoor units equipped with indoor heat exchangers and an outdoor heat exchanger, and includes an outdoor unit connected to the indoor units. The outdoor unit comprises a compressor, an accumulator connected to the compressor, a subcooler for subcooling a refrigerant, a subcooling electronic expansion valve for controlling the flow rate of the refrigerant flowing through the subcooler, a plurality of temperature sensors, a first refrigerant pipe connecting the subcooler and the accumulator, a first valve provided in the first refrigerant pipe, a second refrigerant pipe connecting the subcooler and the compressor, a second valve provided in the second refrigerant pipe, and a control unit for diagnosing a failure of the subcooling electronic expansion valve based on temperature data measured by the plurality of temperature sensors when the first valve or the second valve is open.

[0016] The above second refrigerant pipe can be connected to the medium pressure section of the compressor.

[0017] The first valve above can be opened during cooling operation.

[0018] The above second valve can be opened during heating operation.

[0019] The plurality of temperature sensors may include a first temperature sensor for measuring the inlet temperature of the supercooler, a second temperature sensor for measuring the outlet temperature of the supercooler, a third temperature sensor for measuring the evaporation temperature, and a fourth temperature sensor for measuring the internal temperature of the outdoor unit.

[0020] The control unit can diagnose a failure of the supercooling electronic expansion valve based on the outlet temperature of the supercooler, the inlet temperature of the supercooler, and the evaporation temperature when the first valve is open.

[0021] The control unit can determine that the first valve is open, the opening of the supercooling electronic expansion valve is at the maximum opening, and the difference between the outlet temperature of the supercooler and the evaporation temperature is greater than the target value, thereby determining that it is stuck closed.

[0022] The control unit can determine that the first valve is open, the opening of the supercooling electronic expansion valve is at the maximum opening, and the difference between the outlet temperature of the supercooler and the evaporation temperature is greater than or equal to the sum of the target value and the first reference value, thereby determining that it is stuck closed.

[0023] The control unit can determine that the opening is stuck if, when the first valve is open, the opening of the supercooling electronic expansion valve is at a minimum opening and the difference between the outlet temperature of the supercooler and the evaporation temperature is smaller than the target value.

[0024] The control unit can determine that the opening is stuck if, when the first valve is open, the opening of the supercooling electronic expansion valve is at the minimum opening, and the difference between the outlet temperature of the supercooler and the evaporation temperature is less than or equal to the difference between the target value and the second reference value.

[0025] The control unit can diagnose a failure of the supercooling electronic expansion valve based on the outlet temperature of the supercooler, the inlet temperature of the supercooler, and the internal temperature of the outdoor unit when the second valve is open.

[0026] The control unit can determine that the second valve is closed if, when the second valve is open, the opening of the supercooling electronic expansion valve is at the maximum opening, and the difference between the outlet temperature of the supercooler and the inlet temperature of the supercooler is greater than the target value.

[0027] The control unit can determine that the second valve is closed if, when the second valve is open, the opening of the supercooling electronic expansion valve is at the maximum opening, and the difference between the outlet temperature of the supercooler and the inlet temperature of the supercooler is greater than or equal to the sum of the target value and the third reference value.

[0028] The control unit can determine that the opening is stuck when, with the second valve open, the opening degree of the supercooling electronic expansion valve is at the minimum opening degree, the difference between the outlet temperature of the supercooler and the inlet temperature of the supercooler is at or below the fourth reference value, and the discharge superheat is lowered to or below the normal reference value.

[0029] The control unit can determine that the second valve is open, the opening degree of the supercooling electronic expansion valve is at the minimum opening degree, the difference between the outlet temperature of the supercooler and the inlet temperature of the supercooler is less than or equal to the fourth reference value, and the outlet temperature of the supercooler is lower than the internal temperature of the outdoor unit, in which case it is determined to be completely locked.

[0030] The control unit can determine that the outlet temperature of the supercooler is lower than the internal temperature of the outdoor unit when the second valve is open.

[0031] According to at least one of the embodiments of the present disclosure, a failure of a supercooled electronic expansion valve in an air conditioning system can be automatically diagnosed.

[0032] According to at least one of the embodiments of the present disclosure, a failure of the supercooled electronic expansion valve can be detected quickly, allowing for a rapid response to the occurrence of a failure, thereby enabling stable maintenance of system performance and efficient operation.

[0033] According to at least one of the embodiments of the present disclosure, failures can be diagnosed early to reduce unnecessary maintenance costs and extend lifespan.

[0034] According to at least one of the embodiments of the present disclosure, supercooler and cycle performance can be optimized through an automated diagnostic system.

[0035] Meanwhile, various other effects will be disclosed directly or implicitly in the detailed description according to the embodiments of the present disclosure to be described below.

[0036] FIG. 1 is a schematic diagram of an air conditioner system according to one embodiment of the present disclosure.

[0037] FIG. 2 is a schematic diagram of a supercooling electronic expansion valve control unit according to one embodiment of the present disclosure.

[0038] FIGS. 3 to 5 are drawings referenced in the description of the cycle and supercooling electronic expansion valve when using the first valve.

[0039] FIGS. 6 to 8 are drawings referenced in the description of the cycle and supercooling electronic expansion valve when using the second valve.

[0040] FIG. 9 is a flowchart of the entry conditions for the fault diagnosis logic of a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0041] FIG. 10 is a flowchart of a fault diagnosis logic for a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0042] FIG. 11 is a flowchart of a fault diagnosis logic for a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0043] FIG. 12 is a flowchart of a fault diagnosis logic for a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0044] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components are given the same reference numeral regardless of drawing symbols, and redundant descriptions thereof will be omitted.

[0045] The suffixes “module” and “part” for components used in the following description are assigned or used interchangeably solely for the ease of drafting the specification, and do not inherently possess distinct meanings or roles.

[0046] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0047] When it is stated that one component is “connected” or “connected” to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

[0048] FIG. 1 is a schematic diagram of an air conditioner system according to one embodiment of the present disclosure.

[0049] Referring to FIG. 1, an air conditioner according to one embodiment of the present disclosure includes an outdoor unit (20) and a plurality of indoor units (10) connected to the outdoor unit (20).

[0050] The outdoor unit (20) includes a compressor (122) and an outdoor heat exchanger (124) that exchanges heat between the refrigerant flowing through the compressor (122) and the outside air.

[0051] Each of the plurality of indoor units (10) may include an indoor heat exchanger (112) that exchanges heat between the air supplied to the indoor unit and the refrigerant, and an indoor expansion valve (114) that expands the refrigerant flowing into the indoor heat exchanger (112).

[0052] Referring to FIG. 1, a plurality of indoor units (10) are equipped with an indoor heat exchanger (112) and are connected to the outdoor unit (20) by a plurality of pipes (2, 4). A service valve (2a, 4a) for opening and closing the pipe (2, 4) may be provided in each pipe (2, 4).

[0053] Referring to FIG. 1, the outdoor unit (20) and the plurality of indoor units (10) can be connected by a first pipe (2) and a second pipe (4). The first pipe (2) can connect an outdoor heat exchanger (124) and an indoor heat exchanger (112). The second pipe (4) can connect an indoor heat exchanger (112) and a switching valve (120).

[0054] The air conditioner may include a switching valve (120) that sends the refrigerant discharged from the compressor (122) to at least one of the outdoor heat exchanger (124) and the indoor heat exchanger (112). The outdoor heat exchanger (124) can be switched to a condenser or an evaporator through the control of the switching valve (120).

[0055] Referring to FIG. 1, the first pipe (2) is branched and connected to each indoor unit (10). The second pipe (4) is also connected to each indoor unit (10).

[0056] According to an embodiment, the first pipe (2) may be a liquid pipe through which liquid refrigerant flows. The second pipe (4) may be a pipe through which gaseous refrigerant flows. Depending on the operating mode of the indoor unit (10), the second pipe (4) may flow high temperature and high pressure refrigerant or low temperature and low pressure refrigerant.

[0057] The outdoor unit (20) may include an outdoor expansion valve (130) that expands the refrigerant flowing into or from the outdoor heat exchanger (124). The outdoor expansion valve (130) may be placed in the first pipe (2).

[0058] The first pipe (2) is connected to an outdoor heat exchanger (124), and the outdoor expansion valve (130) may be positioned on the outdoor heat exchanger (124) side of the first pipe (2). Additionally, the first pipe (2) and the outdoor heat exchanger (124) may be connected by a sub-liquid pipe (144), and the outdoor expansion valve (130) may be positioned in the sub-liquid pipe (144).

[0059] The outdoor expansion valve (130) can expand the refrigerant flowing to the outdoor heat exchanger (124) during heating operation, and can pass the refrigerant without expansion during cooling operation. The outdoor expansion valve (130) may be an electronic expansion valve (EEV) capable of adjusting the opening value according to an input signal.

[0060] An outdoor heat exchanger connecting pipe (138) connecting the first switching valve (128) and the outdoor heat exchanger (124) may be provided in the outdoor unit (20).

[0061] The outdoor unit (20) may include an oil separator (not shown) that recovers oil from the refrigerant discharged from the compressor (122). The oil separated from the oil separator may be recovered to the compressor (122) through an oil recovery path (not shown).

[0062] The outdoor unit (20) further includes an accumulator (134) connected to the compressor (122).

[0063] It includes an accumulator (134) that separates the refrigerant flowing to the compressor (122) into gaseous refrigerant and liquid refrigerant, and sends the separated gaseous refrigerant to the compressor (122).

[0064] The suction passage (177) can connect the accumulator (134) and the compressor (122). The switching valve (120) and the accumulator (134) can be connected by a pipe (121).

[0065] The suction path (177) can guide the gaseous refrigerant from the accumulator (134) to the compressor (122). The gaseous refrigerant can be discharged from the accumulator (134) into the suction path (177) and sucked into the compressor (122). The refrigerant discharged from the accumulator (134) can be supplied to the compressor (122) through the suction path (177).

[0066] The compressor (122) can be connected to the accumulator (134). The refrigerant suction path of the compressor (122) can be in communication with the accumulator (134). The compressor (122) can discharge refrigerant into the discharge path (159). The compressor (122) or the oil separator can be connected to the discharge path (159).

[0067] The outdoor unit (20) may include an outdoor fan. The outdoor fan may be positioned to face the outdoor heat exchanger (126). The outdoor fan may perform the function of blowing outside air to the outdoor heat exchanger (126).

[0068] The refrigerant flow is controlled according to the operation of the switching valve (120). The switching valve (120) can switch the outdoor heat exchanger (124) to a condenser or an evaporator. The switching valve (120) may be a four-way valve. The operation of the switching valve (120) can determine the operating mode of the outdoor heat exchanger (124).

[0069] An air conditioner according to the present disclosure can operate in a heating cycle or a cooling cycle, wherein the refrigerant flow is controlled by switching of the switching valve (120). The refrigerant flow direction in the heating cycle and the cooling cycle may be opposite.

[0070] The outdoor unit (20) may include a subcooling unit (167) that subcools a portion of the refrigerant flowing through the first pipe (2) and sends it to a compressor (122) or an accumulator (134). The subcooling unit (167) is connected to the first pipe (2), and the first pipe (2) may extend outside the outdoor unit (20). The cooler (167) can perform the function of subcooling the refrigerant.

[0071] The subcooling unit (167) may include a subcooler (167a), a bypass path (167b), and a subcooling electronic expansion valve (167c). The bypass path (167b) may connect the first pipe (2) and the subcooler (167a). When operating the cooling room or the main cooling unit simultaneously, the bypass path (167b) may guide a portion of the refrigerant flowing along the first pipe (2) into the subcooler (167a).

[0072] The supercooler (167a) can be installed by wrapping around a portion of the first pipe (2).

[0073] A subcooling electronic expansion valve (167c) can be installed in a bypass path (167b). When operating a cooling room or a cooling main unit simultaneously, the refrigerant flowing through the bypass path (167b) can pass through the subcooling electronic expansion valve (167c), expand, and be guided into the subcooler (167a).

[0074] The subcooler (167a) and the accumulator (134) can be connected through the first refrigerant pipe (170). A first valve (172) can be placed in the first refrigerant pipe (170).

[0075] The subcooler (167a) and the compressor (122) can be connected through the second refrigerant pipe (184). A second valve (188) can be placed in the second refrigerant pipe (184).

[0076] The second refrigerant pipe (184) can be connected to the medium pressure end of the compressor (122). The suction side of the compressor (122) is a low pressure area, the discharge side of the compressor (122) is a high pressure area, and the area to which the second refrigerant pipe (184) is connected may be a medium pressure area.

[0077] An outlet pipe (167d) is connected to the outlet of the subcooler (167a), and the outlet pipe (167d) can be connected to the first refrigerant pipe (170) and the second refrigerant pipe (184).

[0078] During cooling operation, the high-temperature, high-pressure refrigerant discharged from the compressor (122) flows toward the outdoor heat exchanger (124) by controlling the flow path of the switching valve (120). The refrigerant condensed at the outdoor heat exchanger (124) flows toward the subcooler (167a). Some of the refrigerant that has passed through the subcooler (167a) flows through the bypass path (167b) and is expanded by the subcooling electronic expansion valve (167c). Then, the refrigerant expanded by the subcooling electronic expansion valve (167c) flows into the subcooler (167a) and exchanges heat with the condensed refrigerant flowing along the first pipe (2).

[0079] The refrigerant flowing along the bypass path (167b) has its temperature and pressure lowered as it passes through the subcooling electronic expansion valve (167c). Therefore, the temperature of the refrigerant passing through the subcooling electronic expansion valve (167c) is relatively lower than the temperature of the refrigerant flowing through the first pipe (2). Consequently, the condensed refrigerant is subcooled as it passes through the subcooler (167a). As the condensed refrigerant is subcooled, the refrigerant in a low-temperature state can be introduced into the indoor heat exchanger (112), thereby further increasing the amount of heat absorbed from the indoor air and improving the overall cooling performance of the air conditioner.

[0080] Even when the air conditioner is operating in heating mode, the refrigerant can be supercooled, and the supercooled refrigerant flows into the outdoor heat exchanger (124). Thus, the heating performance of the air conditioner can be improved.

[0081] Meanwhile, during cooling operation, the first valve (172) can be opened and the second valve (188) can be closed. Accordingly, the refrigerant can flow into the accumulator (134).

[0082] During heating operation, the first valve (172) is closed and the second valve (188) can be opened. Accordingly, the refrigerant can flow into the medium pressure section of the compressor (122). Since the medium pressure refrigerant is injected into the compressor (122), the differential pressure between the high and low pressures of the compressor (122) is reduced, and the flow rate of the refrigerant discharged from the compressor (122) and flowing to the condenser is increased, which has the advantage of improving cycle performance.

[0083] Meanwhile, in a situation where there is a risk of liquid refrigerant entering when gaseous refrigerant needs to enter the compressor (122), the first valve (172) can be opened and the second valve (188) can be closed.

[0084] A plurality of temperature sensors (100) may be disposed in the outdoor unit (20). For example, an outdoor heat exchanger temperature sensor may measure the temperature of the outdoor heat exchanger (124). Additionally, an outdoor heat exchanger outlet temperature sensor may be disposed at the outlet side of the outdoor heat exchanger (124) to measure the temperature of the refrigerant condensed in the outdoor heat exchanger (124). Furthermore, a plurality of pressure sensors may be disposed in the outdoor unit (20).

[0085] Meanwhile, in order to detect the temperature of the refrigerant flowing in / out of the subcooling unit (167), temperature sensors (101, 102) are respectively installed at the inlet and outlet sides of the subcooler (167a). The temperature sensors (101, 102) may be attached to the front and rear ends (inlet and outlet) of the subcooler (167a), respectively. The temperature sensors (101, 102) may be installed in the piping connected to the inlet and outlet of the subcooler (167a), respectively.

[0086] A plurality of temperature sensors (100) include a first temperature sensor (101) for measuring the inlet temperature of the supercooler (167a) and a second temperature sensor (102) for measuring the outlet temperature of the supercooler (167a).

[0087] Additionally, the plurality of temperature sensors (100) includes a third temperature sensor (103) for measuring the evaporation temperature. The third temperature sensor (103) can measure the evaporation temperature of the evaporator. The evaporation temperature can be measured by a temperature and pressure sensor as a position representing the evaporation temperature of the heat pump system.

[0088] Additionally, the plurality of temperature sensors (100) includes a fourth temperature sensor (104) that measures the internal temperature (To) of the outdoor unit (20). The fourth temperature sensor (104) can directly measure the internal temperature (To) of the outdoor unit (20). Alternatively, the fourth temperature sensor (104) may measure the outdoor temperature and the outdoor unit heat exchanger temperature, and the internal temperature (To) of the outdoor unit (20) may be estimated based on the measured values.

[0089] FIG. 2 is a schematic diagram of a supercooling electronic expansion valve control unit according to one embodiment of the present disclosure.

[0090] Referring to FIGS. 1 and 2, the subcooler (167a) can reduce the pressure of a portion of the high-pressure liquid refrigerant from the condenser through the subcooling electronic expansion valve (167c) to produce a low-temperature or medium-temperature ideal refrigerant, and can further secure the system's subcooling degree by exchanging heat with the existing high-pressure liquid refrigerant.

[0091] Depending on the control method, there is a method of opening the first valve (172) to send low-pressure refrigerant to the accumulator (134) and a method of opening the second valve (188) to send it to the medium-pressure side of the compressor (122).

[0092] The control unit (200) can control the on / off of the first valve (172) and the second valve (188) (300).

[0093] Additionally, depending on the control method, the control unit (200) can adjust the opening degree of the supercooling electronic expansion valve (167c) based on temperature data measured by a plurality of temperature sensors (100) (400).

[0094] The control unit (200) controls the amount of refrigerant flowing through the subcooling unit (167a) by controlling the opening of the subcooling electronic expansion valve (167c). Specifically, the control of the opening of the subcooling electronic expansion valve (167c) can be performed by changing the pulse value for opening the subcooling electronic expansion valve (167c). The flow rate of the refrigerant flowing to the subcooling electronic expansion valve (167c) can be determined by the pulse value for opening the subcooling electronic expansion valve (167c).

[0095] The control unit (200) appropriately adjusts the opening of the supercooling electronic expansion valve (167c) using the values ​​of the first to third temperature sensors (101, 102, 103) according to each control method. Accordingly, sufficient gaseous superheated refrigerant can be introduced into the accumulator (134) and the compressor (122).

[0096] The control unit (200) diagnoses a failure of the supercooling electronic expansion valve (167c) based on temperature data measured by a plurality of temperature sensors (100) when the first valve (172) or the second valve (188) is open.

[0097] The fault diagnosis method of the present disclosure is a cycle-based judgment method that does not utilize a voltage and current-based artificial intelligence model, and does not require high-level computation and data storage capabilities. In addition, the fault diagnosis method of the present disclosure can diagnose a fault by controlling the opening of the supercooling electronic expansion valve (167c) that is controlled during operation, rather than intentionally controlling it to a specific opening for fault diagnosis.

[0098] According to an embodiment, the control unit (200) may use temperature data corresponding to the state in which the first valve (172) or the second valve (188) is opened among the temperature data measured by a plurality of temperature sensors (100). Accordingly, fault diagnosis can be performed more accurately according to the control method.

[0099] With the first valve (172) open, the control unit (200) can diagnose a failure of the supercooling electronic expansion valve (167c) based on the outlet temperature of the supercooler (167a) measured by the second temperature sensor (102), the inlet temperature of the supercooler (167a) measured by the first temperature sensor (101), and the evaporation temperature measured by the third temperature sensor (103).

[0100] With the second valve (188) open, the control unit (200) can diagnose a failure of the supercooling electronic expansion valve (167c) based on the outlet temperature of the supercooler (167a) measured by the second temperature sensor (102), the inlet temperature of the supercooler (167a) measured by the first temperature sensor (101), and the internal temperature of the outdoor unit measured by the fourth temperature sensor (104).

[0101] According to the present disclosure, data is automatically collected and analyzed through the sensor (100) and the control unit (200) so that the condition of the supercooling electronic expansion valve (167c) can be monitored and a fault diagnosed without user intervention.

[0102] The control unit (200) can enter fault diagnosis logic when the system is operating normally.

[0103] The fault diagnosis logic for controlling the first valve (172) is such that when the supercooling electronic expansion valve (167c) is controlled to the maximum opening, if △T1 (supercooling out temperature (outlet temperature of the supercooler (167a) - evaporation temperature) is high, it can be determined that the valve is stuck closed.

[0104] Here, the fixation may mean a fixed state in which the opening of the supercooling electronic expansion valve (167c) is not adjusted according to the control of the control unit (400).

[0105] Meanwhile, in the present specification, the maximum opening is a controllable maximum value for controlling the opening of the supercooling electronic expansion valve (167c), which may be the state where the supercooling electronic expansion valve (167c) is most open. The maximum opening is a controllable minimum value for controlling the opening of the supercooling electronic expansion valve (167c), which may be the state where the supercooling electronic expansion valve (167c) is most closed.

[0106] Meanwhile, the fault diagnosis logic for controlling the first valve (172) can be determined as open when △T1 is low when controlling the supercooling electronic expansion valve (167c) to the minimum opening.

[0107] The fault diagnosis logic for controlling the second valve (188) is such that when the supercooling electronic expansion valve (167c) is controlled to the maximum opening, if △T2 (supercooling out temperature (outlet temperature of the supercooler (167a)) - supercooling in temperature (inlet temperature of the supercooler (167a)) is high, it can be determined that the valve is stuck closed.

[0108] The fault diagnosis logic for controlling the second valve (188) can be determined as open sticking if △T2 is low and the discharge superheat is low when controlling the supercooling electronic expansion valve (167c) to the minimum opening. Additionally, if the supercooling out temperature (outlet temperature of the supercooler (167a)) is lower than the indoor unit internal temperature, it can be determined as completely locked sticking. Completely locked sticking may mean that the supercooling electronic expansion valve (167c) is fixed in a completely closed state.

[0109] Hereinafter, a fault diagnosis logic according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0110] FIGS. 3 to 5 are drawings referenced in the description of the cycle and supercooling electronic expansion valve when using the first valve.

[0111] Referring to FIG. 3, the first valve (172) can be opened to control the flow of refrigerant passing through the subcooler (167a) into the accumulator (134) through the first valve (172). The refrigerant separated from the accumulator (134) can be supplied to the compressor (122). FIG. 4 illustrates the case where the subcooler is used and the case where it is not used on a pH graph.

[0112] The control unit (200) monitors the difference between the outlet temperature and the evaporation temperature of the subcooler (167a), and if the difference is greater than the target value (e.g., 15℃, changeable), it opens the subcooling electronic expansion valve (167c), and if the difference is smaller, it closes the subcooling electronic expansion valve (167c) to control the temperature to approach the target value.

[0113] The refrigerant upstream of the supercooling electronic expansion valve (167c) is generally a liquid refrigerant and must be converted into a gaseous refrigerant as it passes through the supercooler (167a). However, since efficiency decreases if it is overheated, the target value can be set while also taking efficiency into account.

[0114] Referring to FIG. 5, when the first valve (172) is used, the failure of the supercooled electronic expansion valve (167c) shows the following three patterns.

[0115] When the supercooling electronic expansion valve (167c) is stuck at an opening smaller than the appropriate value, even if the supercooling electronic expansion valve (167c) is close to full opening, △(supercooling out temperature - evaporation temperature) maintains a value higher than the target value.

[0116] In addition, when the supercooling electronic expansion valve (167c) is stuck in an open state relative to the appropriate level, even though the supercooling electronic expansion valve (167c) is almost closed, △(supercooling out temperature - evaporation temperature) maintains a value lower than the target value.

[0117] When the subcooling electronic expansion valve (167c) is stuck in a completely closed position, there is almost no refrigerant flow in the refrigerant piping line after the subcooling electronic expansion valve (167c), so the subcooling out temperature approaches the temperature inside the outdoor unit. In this pattern, a cycle pattern of small opening stuck or large opening stuck appears depending on the temperature inside the outdoor unit.

[0118] FIGS. 6 to 8 are drawings referenced in the description of the cycle and supercooling electronic expansion valve when using the second valve.

[0119] Referring to FIG. 6, the second valve (188) can be opened so that the refrigerant passing through the subcooler (167a) flows into the medium pressure end of the compressor (122) through the second valve (188). FIG. 7 illustrates the case where the subcooler is used and the case where it is not used on the pH diagram.

[0120] At this time, the control target value is the value of the temperature difference between supercooling out and supercooling in, and generally has a value of 0°C or higher. Even when using the second valve (188), the following three patterns are observed when the supercooling electronic expansion valve (167c) fails.

[0121] Referring to FIG. 8, when the supercooling electronic expansion valve (167c) is stuck at an opening smaller than the appropriate value, even when the supercooling electronic expansion valve (167c) is close to full opening, △(supercooling out temperature - supercooling in temperature) maintains a value higher than the target value.

[0122] In addition, when the supercooling electronic expansion valve (167c) is stuck in an open state relative to the appropriate level, even though the supercooling electronic expansion valve (167c) is almost closed, △(supercooling out temperature - supercooling in temperature) maintains a value lower than the target value.

[0123] In addition, unlike the control of the first valve (172), the refrigerant is introduced directly into the compressor (122), so when the supercooling electronic expansion valve (167c) is opened excessively, liquid refrigerant is introduced into the compressor (122), causing a decrease in the discharge superheat.

[0124] In addition, if the subcooling electronic expansion valve (167c) is stuck in a completely closed position, there is almost no refrigerant flow in the refrigerant piping line after the subcooling electronic expansion valve (167c), so the subcooling out temperature approaches the internal temperature of the outdoor unit. However, since this temperature range is close to the evaporation temperature, unlike the small opening or large opening, it is necessary to use a value that can represent the internal temperature of the outdoor unit.

[0125] FIG. 9 is a flowchart of the entry conditions for the fault diagnosis logic of a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0126] The control unit (200) does not perform fault diagnosis because the temperature data is not stabilized before the cycle is stabilized, such as during the initial operation.

[0127] The control unit (200) checks whether the supercooling electronic expansion valve (167c) judgment condition is reached when the cycle is stabilized (S910) (S920).

[0128] The supercooling electronic expansion valve (167c) determination condition includes the first valve (172) or the second valve (188) being in an open state.

[0129] In addition, since no separate inefficient control operation is performed for fault diagnosis, it is possible to diagnose whether a fault exists when the supercooling electronic expansion valve (167c) is open and the supercooler (167a) is in use or has been used.

[0130] Meanwhile, the control unit (200) performs an operation corresponding to the cycle abnormality if the current cycle corresponds to an abnormal cycle such as an error, excess refrigerant, or insufficient refrigerant.

[0131] The control unit (200) enters the supercooling electronic expansion valve (167c) fault diagnosis logic if the current cycle does not correspond to an abnormal cycle (S930).

[0132] The control unit (200) enters the fault diagnosis logic when the system is operating normally.

[0133] FIG. 10 is a flowchart of a fault diagnosis logic for a supercooled electronic expansion valve according to one embodiment of the present disclosure. FIG. 10 illustrates a fault diagnosis logic when the first valve (172) is in an open state (S1000).

[0134] The control unit (200) can determine the stuck state by monitoring the opening degree of the supercooling electronic expansion valve (167c) and △T1 (supercooling out temperature - evaporation temperature) when the first valve (172) is in an open state (S1000).

[0135] The control unit (200) determines whether the opening of the supercooling electronic expansion valve (167c) is greater than the opening degree when the first valve (172) is open (S1000). Here, the opening degree is the maximum opening degree or a set opening degree equivalent to the maximum opening degree.

[0136] The control unit (200) can determine that the supercooling electronic expansion valve (167c) is faulty (S1300) if, when the first valve (172) is open (S1000), the opening degree of the supercooling electronic expansion valve (167c) is at the maximum opening degree (S1010), and the difference between the outlet temperature of the supercooler (167a) and the evaporation temperature is greater than the target value (S1020). More specifically, the control unit (200) can determine that it is stuck in the closed position (S1300).

[0137] In addition, the control unit (200) can determine whether there is a fault by correcting the target value instead of using the target value as is.

[0138] For example, the control unit (200) can determine that the first valve (172) is open (S1000), the opening degree of the supercooling electronic expansion valve (167c) is the maximum opening degree (S1010), and the difference between the outlet temperature and the evaporation temperature of the supercooler (167a) is greater than or equal to the sum of the target value and the first reference value (ex, a) (S1020), and that it is stuck closed (S1300).

[0139] Meanwhile, the control unit (200) determines whether the opening degree of the supercooling electronic expansion valve (167c) is less than or equal to the closing degree when the first valve (172) is open (S1000). Here, the closing degree is the minimum opening degree or a set opening degree equivalent to the minimum opening degree.

[0140] The control unit (200) can determine that the supercooling electronic expansion valve (167c) is faulty (S1300) if, when the first valve (172) is open (S1000), the opening degree of the supercooling electronic expansion valve (167c) is at the minimum opening degree (S1030), and the difference between the outlet temperature of the supercooler (167a) and the evaporation temperature is smaller than the target value (S1040). More specifically, the control unit (200) can determine that the valve is stuck open (S1300).

[0141] In this case as well, the control unit (200) can determine whether there is a fault by correcting the target value instead of using the target value as is.

[0142] For example, the control unit (200) can determine that the first valve (172) is open (S1000), the opening degree of the supercooling electronic expansion valve (167c) is the minimum opening degree (S1030), and the difference between the outlet temperature and the evaporation temperature of the supercooler (167a) is less than or equal to the difference between the target value and the second reference value (ex, a) (S1040) (S1300).

[0143] Figure 10 illustrates a case where the first and second reference values ​​are used as the same 'a' value, but the first and second reference values ​​may be different.

[0144] According to an embodiment, the control unit (200) can determine that the supercooling electronic expansion valve (167c) is stuck in the closed position if △T1 (supercooling out temperature - evaporation temperature) is higher than the target value when the opening of the supercooling electronic expansion valve (167c) is at the maximum opening, and determine that the valve is stuck in the open position if △T1 is significantly lower when the opening is at the minimum opening. That is, only when the opening is at the minimum opening, the target value may not be used as is, but may be corrected to be lower and used.

[0145] FIG. 11 is a flowchart of a fault diagnosis logic for a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0146] FIG. 11 illustrates a fault diagnosis logic when the second valve (188) is in an open state (S1100).

[0147] The control unit (200) can determine the stuck state by monitoring the opening degree of the supercooling electronic expansion valve (167c) and △T2 (supercooling out temperature - supercooling in temperature) when the second valve (188) is in an open state (S1100).

[0148] The control unit (200) determines whether the opening degree of the supercooling electronic expansion valve (167c) is greater than the opening degree when the second valve (188) is open (S1100).

[0149] The control unit (200) can determine that the supercooling electronic expansion valve (167c) is faulty (S1300) if, when the second valve (188) is open (S1100), the opening degree of the supercooling electronic expansion valve (167c) is at the maximum opening degree (S1110), and the difference between the outlet temperature of the supercooler (167a) and the inlet temperature of the supercooler (167a) is greater than the target value (S1220). More specifically, the control unit (200) can determine that it is stuck in the closed position (S1300).

[0150] In addition, the control unit (200) can determine whether there is a fault by correcting the target value instead of using the target value as is.

[0151] For example, the control unit (200) can determine that the second valve (188) is open (S1100), the opening of the supercooling electronic expansion valve (167c) is at the maximum opening (S1110), and the difference between the outlet temperature of the supercooler (167a) and the inlet temperature of the supercooler (167a) is greater than or equal to the sum of the target value and the third reference value (ex, b) (S1120), thereby determining that it is stuck closed (S1300). The third reference value can be set to be smaller than the first and second reference values.

[0152] Meanwhile, the control unit (200) determines whether the opening degree of the supercooling electronic expansion valve (167c) is less than or equal to the closing degree when the second valve (188) is open (S1100) (S1130).

[0153] The control unit (200) can determine whether, when the second valve (188) is open (S1100), the opening degree of the supercooling electronic expansion valve (167c) is the minimum opening degree (S1130), and whether the difference between the outlet temperature of the supercooler (167a) and the inlet temperature of the supercooler (167a) is less than or equal to a fourth reference value (ex, c) (S1140). The fourth reference value may be set to be smaller than the third reference value. For example, the fourth reference value may be 0°C.

[0154] The control unit (200) can determine that the supercooling electronic expansion valve (167c) is malfunctioning (S1300) when the discharge superheat level drops below a normal reference value (ex, d) (S1150). More specifically, the control unit (200) can determine that it is stuck open (S1300). The normal reference value may be greater than the first and second reference values.

[0155] Alternatively, the control unit (200) may determine that the supercooling electronic expansion valve (167c) is faulty when the outlet temperature of the supercooler (167a) is lower than the internal temperature (To) of the outdoor unit (S1150) (S1300). More specifically, the control unit (200) may determine that it is stuck in a completely locked state (S1300).

[0156] FIG. 12 is a flowchart of a fault diagnosis logic for a supercooled electronic expansion valve according to one embodiment of the present disclosure.

[0157] Referring to FIG. 12, the control unit (200) determines whether the first valve (172) and the second valve (188) are open (S1200) and determines them using different diagnostic logic.

[0158] When controlling the opening of the first valve (172), if the opening of the supercooling electronic expansion valve (167c) is at the maximum opening or a set opening equivalent thereto (opening opening) (S1010), the supercooling electronic expansion valve (167c) can be seen as being in a greatly opened state.

[0159] If △T1 (subcooling out temperature - evaporation temperature) (which can also be changed to subcooling out temperature - subcooling in temperature depending on the control method) is higher than the target value (S1020), the control unit (200) determines that the subcooling electronic expansion valve (167c) is not properly opened despite the control that opens the opening degree too much, and determines that the subcooling electronic expansion valve (167c) is stuck in the closed position (S1300).

[0160] If the supercooling electronic expansion valve (167c) is at a minimum opening or a set opening equivalent thereto (closed opening) (S1030), and △T1 is significantly low (S1040), it is determined that the supercooling electronic expansion valve (167c) is stuck open, as it is considered that the supercooling electronic expansion valve (167c) is not properly closed despite control to close the opening (S1300).

[0161] When controlling the opening of the second valve (188), if the opening of the supercooling electronic expansion valve (167c) is at the maximum opening or a set opening equivalent thereto (opening) (S1110), the supercooling electronic expansion valve (167c) can be seen as being in a greatly opened state.

[0162] Meanwhile, if △T2 (subcooling out temperature - subcooling in temperature) is higher than the target value (S1120), the control unit (200) determines that the subcooling electronic expansion valve (167c) is not properly opened despite control to open the opening degree significantly, and determines that the subcooling electronic expansion valve (167c) is stuck in the closed position (S1300).

[0163] If the supercooling electronic expansion valve (167c) is at a minimum opening or a set opening equivalent thereto (closed opening) (S1130), △T2 is significantly low (S1140), and the discharge superheat level is lowered below a normal level (S1150), it is determined that the supercooling electronic expansion valve (167c) is not properly closed despite control to close the opening (S1300).

[0164] If the supercooling out temperature is lower than the internal temperature of the outdoor unit (S1150), it is determined that the supercooling electronic expansion valve (167c) is completely locked, and finally, it is determined that the supercooling electronic expansion valve (167c) is stuck (S1300).

[0165] According to at least one of the embodiments of the present disclosure, a failure of a supercooled electronic expansion valve in an air conditioning system can be automatically and quickly detected. Accordingly, unnecessary maintenance costs can be reduced, the performance of the system can be maintained stably and efficient operation can be enabled, and the product life can be extended.

[0166] Although preferred embodiments of the present disclosure have been illustrated and described above, the present disclosure is not limited to the specific embodiments described above, and it is obvious that various modifications can be made by those skilled in the art without departing from the gist of the present disclosure as claimed in the patent claims.

Claims

1. A plurality of indoor units equipped with indoor heat exchangers; and It includes an outdoor unit connected to the indoor unit and equipped with an outdoor heat exchanger; The above outdoor unit is, compressor, Accumulator connected to the above compressor, A subcooler that subcools a refrigerant, A subcooling electronic expansion valve that controls the flow rate of the refrigerant flowing through the above subcooler, Multiple temperature sensors, A first refrigerant pipe connecting the above-mentioned supercooler and the above-mentioned accumulator, A first valve provided in the first refrigerant pipe, A second refrigerant pipe connecting the above subcooler and the above compressor, A second valve provided in the second refrigerant pipe, and, An air conditioner comprising a control unit that diagnoses a failure of the supercooling electronic expansion valve based on temperature data measured by the plurality of temperature sensors when the first valve or the second valve is open.

2. In Paragraph 1, The above second refrigerant pipe is an air conditioner connected to the medium pressure section of the above compressor.

3. In Paragraph 1, The above-mentioned first valve is an air conditioner that opens during cooling operation.

4. In Paragraph 1, The above second valve is an air conditioner that opens during heating operation.

5. In Paragraph 1, The above plurality of temperature sensors are, A first temperature sensor for measuring the inlet temperature of the above-mentioned supercooler, and A second temperature sensor for measuring the outlet temperature of the above-mentioned supercooler, and A third temperature sensor for measuring evaporation temperature and An air conditioner comprising a fourth temperature sensor for measuring the internal temperature of the outdoor unit.

6. In Paragraph 5, The above control unit is, With the first valve above open, An air conditioner that diagnoses a failure of the supercooling electronic expansion valve based on the outlet temperature of the supercooler, the inlet temperature of the supercooler, and the evaporation temperature.

7. In Paragraph 6, The above control unit is, With the first valve above open, An air conditioner that determines that the opening of the above-mentioned supercooling electronic expansion valve is the maximum opening, and that the difference between the outlet temperature of the above-mentioned supercooler and the above-mentioned evaporation temperature is greater than the target value, is stuck in the closed position.

8. In Paragraph 6, The above control unit is, With the first valve above open, An air conditioner that determines that the opening of the above-mentioned supercooling electronic expansion valve is the maximum opening, and that the difference between the outlet temperature of the above-mentioned supercooler and the above-mentioned evaporation temperature is greater than or equal to the sum of the target value and the first reference value.

9. In Paragraph 6, The above control unit is, With the first valve above open, An air conditioner that determines that the opening of the above-mentioned supercooling electronic expansion valve is the minimum opening and the difference between the outlet temperature of the above-mentioned supercooler and the above-mentioned evaporation temperature is smaller than the target value is stuck open.

10. In Paragraph 6, The above control unit is, With the first valve above open, An air conditioner that determines that the opening of the above-mentioned supercooling electronic expansion valve is a minimum opening, and that the difference between the outlet temperature of the above-mentioned supercooler and the above-mentioned evaporation temperature is less than or equal to the difference between a target value and a second reference value.

11. In Paragraph 5, The above control unit is, With the above second valve open, An air conditioner that diagnoses a failure of the supercooling electronic expansion valve based on the outlet temperature of the supercooler, the inlet temperature of the supercooler, and the internal temperature of the outdoor unit.

12. In Paragraph 11, The above control unit is, With the above second valve open, An air conditioner that determines that the opening of the above-mentioned supercooling electronic expansion valve is the maximum opening, and that the difference between the outlet temperature of the above-mentioned supercooler and the inlet temperature of the above-mentioned supercooler is greater than the target value, is stuck closed.

13. In Paragraph 11, The above control unit is, With the above second valve open, An air conditioner that determines that the opening of the above-mentioned supercooling electronic expansion valve is the maximum opening, and that the difference between the outlet temperature of the above-mentioned supercooler and the inlet temperature of the above-mentioned supercooler is greater than or equal to the sum of the target value and the third reference value.

14. In Paragraph 11, The above control unit is, With the above second valve open, An air conditioner that determines the opening of the above-mentioned supercooling electronic expansion valve to be stuck open when the opening degree of the above-mentioned supercooling electronic expansion valve is at the minimum opening degree, the difference between the outlet temperature of the above-mentioned supercooler and the inlet temperature of the above-mentioned supercooler is at or below the fourth reference value, and the discharge superheat is lowered to or below the normal reference value.

15. In Paragraph 14, The above control unit is, With the above second valve open, An air conditioner that determines complete locking when the opening degree of the above-mentioned supercooling electronic expansion valve is the minimum opening degree, the difference between the outlet temperature of the above-mentioned supercooler and the inlet temperature of the above-mentioned supercooler is less than or equal to the fourth reference value, and the outlet temperature of the above-mentioned supercooler is lower than the internal temperature of the above-mentioned outdoor unit.

16. In Paragraph 11, The above control unit is, With the above second valve open, An air conditioner that determines complete locking when the outlet temperature of the above-mentioned subcooler is lower than the internal temperature of the above-mentioned outdoor unit.

Images