Air Conditioning Equipment

Abstract

To provide an air conditioner which can accurately detect leakage of a coolant even under various environment and under installation condition.SOLUTION: An air conditioner according to one embodiment includes an outdoor unit, an indoor unit, and a control unit. The control unit has a coolant leakage detection part. The coolant leakage detection part is configured to: acquire an actual opening level that is a current opening level of an indoor expansion valve; calculate a predicted opening level of the indoor expansion valve at least based on a rotational speed of a compressor on assumption of no coolant leakage, a first pressure and second pressure of the coolant, and an opening level of the indoor expansion valve; and detect coolant leakage by comparing a different between the actual opening level and the predicted opening level with a determination threshold. The coolant leakage detection part corrects the determination threshold according to an outdoor temperature such that the determination threshold is larger in a case where the outdoor temperature is lower than a first referential temperature and higher than a second referential temperature than in a case where the outdoor temperature is equal to or higher than the first referential temperature and equal to or lower than the second referential temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to an air conditioning apparatus. [Background technology]

[0002] In an air conditioner in which a refrigerant circulates through piping between an outdoor unit and an indoor unit, the refrigerant may leak from a connection of the piping, etc. For example, in an air conditioner, various information (parameters) of the refrigeration cycle in a state (initial state) that assumes that no refrigerant leakage occurs is acquired, and the current opening of the expansion valve of the outdoor unit is predicted from the acquired information. Then, there is a method for determining whether or not there is a refrigerant leak by assuming the predicted opening as an appropriate value and comparing this opening with the actual opening of the expansion valve. This makes it possible to accurately determine whether or not there is a refrigerant leak.

[0003] However, there are various factors that affect the accuracy of refrigerant leakage detection, and the accuracy may deteriorate depending on the environment and installation conditions, such as fluctuations in outdoor air temperature, the capacity of the indoor unit connected to the outdoor unit, etc. In particular, with variable refrigerant flow control, which is commonly used in air conditioning systems for buildings, it is necessary to consider that the accuracy of refrigerant leakage detection may decrease due to the connection of outdoor units, imbalance in capacity between the outdoor unit and the indoor unit, and operation / stop of each of multiple indoor units. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6130921 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in light of this, and its object is to provide an air conditioning apparatus that is capable of accurately detecting refrigerant leaks even in a variety of environments and installation conditions. [Means for solving the problem]

[0006] An air-conditioning apparatus according to one embodiment includes an outdoor unit, at least one indoor unit, and a control unit, and the outdoor unit and the indoor unit are connected by piping through which a refrigerant flows. The outdoor unit has a compressor, an outdoor heat exchanger, an outdoor blower, a first pressure detection unit, a second pressure detection unit, and an outdoor air temperature detection unit. The compressor draws in a refrigerant, compresses it, and discharges it. The outdoor heat exchanger exchanges heat between outdoor air and the refrigerant. The outdoor blower draws in the outdoor air and blows out the air that has been heat exchanged in the outdoor heat exchanger to the outside. The first pressure detection unit detects a first pressure of the refrigerant discharged from the compressor. The second pressure detection unit detects a second pressure of the refrigerant drawn into the compressor. The outdoor air temperature detection unit detects the outdoor air temperature, which is the temperature of the air outside the room. The indoor unit has an indoor heat exchanger, an indoor blower, and an indoor expansion valve. The indoor heat exchanger exchanges heat between indoor air and the refrigerant. The indoor blower draws in indoor air and blows out the air that has been heat exchanged in the indoor heat exchanger into the room. The indoor expansion valve is configured to be able to adjust the flow rate of the refrigerant depending on its opening degree. The control unit controls the operation of the outdoor unit and the indoor unit. The control unit has a refrigerant leakage detection unit that acquires an actual opening degree, which is a current opening degree, of the indoor expansion valve, calculates a predicted opening degree that is predicted as the current opening degree of the indoor expansion valve based on at least the rotation speed of the compressor, the first pressure and the second pressure of the refrigerant, and the opening degree of the indoor expansion valve, assuming that the refrigerant is not leaking from the piping, and calculates a difference between the actual opening degree and the predicted opening degree. , the value can be corrected from the initial valueThe leakage of the refrigerant from the pipe is detected by comparing with a judgment threshold value. The refrigerant leakage detection unit adjusts the outside air temperature so that the determination threshold is larger when the outside air temperature is less than the first reference temperature and exceeds the second reference temperature than when the outside air temperature is equal to or more than the first reference temperature and equal to or less than a second reference temperature that is greater than the first reference temperature. The initial value is multiplied by the correction coefficient according to the above. The judgment threshold is corrected accordingly. The refrigerant leakage detection unit calculates a ratio between a rated capacity of the outdoor unit and a rated capacity of the indoor unit as a capacity ratio, and adjusts the capacity ratio so that the determination threshold is larger when the capacity ratio is less than the first standard capacity ratio or exceeds the second standard capacity ratio than when the capacity ratio is equal to or greater than a first standard capacity ratio and equal to or less than a second standard capacity ratio that is greater than the first standard capacity ratio. The initial value is multiplied by the correction coefficient according to the above. The judgment threshold is corrected accordingly. [Brief description of the drawings]

[0007] [Figure 1] 1 is a circuit diagram illustrating an air conditioning device according to an embodiment of the present invention. [Diagram 2] 5 is a diagram showing an example of a correction coefficient value depending on an outside air temperature in the air conditioning apparatus according to the embodiment. FIG. [Diagram 3] FIG. 11 is a diagram showing an example of a correction coefficient value based on a capacity ratio in the air conditioning apparatus according to the embodiment. [Figure 4] FIG. 11 is a diagram showing an example of a correction coefficient value based on the ratio of the number of operating units in an air conditioning apparatus according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram that shows a schematic diagram of an air conditioner 1 according to this embodiment. The air conditioner 1 can be operated in either cooling or heating mode. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 2 and an indoor unit 4 that are connected by a flow path through which a refrigerant flows, and a control unit 6 that controls the operation of the outdoor unit 2 and the indoor unit 4. FIG. 1 shows a configuration example that includes one outdoor unit 2 and one indoor unit 4. Not limited to the illustrated example, the air conditioner 1 may include multiple indoor units 4. The flow path is configured by connecting multiple pipes. These pipes include a pipe (hereinafter referred to as an outdoor side pipe) 201 that constitutes the flow path on the outdoor unit 2 side, and a pipe (hereinafter referred to as an indoor side pipe) 401 that constitutes the flow path of the indoor unit 4.

[0009] The outdoor unit 2 has, as main components, a compressor 202, a first pressure detection unit 203, an outdoor heat exchanger 204, an outdoor blower 205, an outdoor expansion valve 206, a second pressure detection unit 207, an outdoor air temperature detection unit 208, a four-way valve 209, and the like.

[0010] The compressor 202 draws in a refrigerant from the suction pipe 201a, compresses it, and discharges the compressed refrigerant to the discharge pipe 201b. The suction pipe 201a and the discharge pipe 201b each constitute a part of the outdoor piping 201. For example, the compressor 202 is configured with a sealed container, a rotating shaft, a compression mechanism, an electric mechanism, etc., and discharges a high-temperature, high-pressure gas-phase refrigerant to the discharge pipe 201b. The compressor 202 gives the value of the rotation speed during operation to the control unit 6 via wire or wireless. One end of the discharge pipe 201b is connected to the discharge port of the compressor 202, and the other end is connected to a four-way valve 209. The four-way valve 209 guides the refrigerant discharged from the compressor 202 to a condenser.

[0011] The first pressure detection unit (hereinafter referred to as the high pressure detection unit) 203 is disposed in the discharge pipe 201b and detects the pressure of the refrigerant discharged from the compressor 202 (first pressure, hereinafter referred to as the discharge pressure), that is, the discharge pressure of the high temperature / high pressure gas phase refrigerant flowing through the discharge pipe 201b. The high pressure detection unit 203 is, for example, a pressure sensor having a pressure sensitive element disposed in the piping of the discharge pipe 201b for detecting the discharge pressure. The high pressure detection unit 203 provides the detected discharge pressure value to the control unit 6 via wire or wirelessly.

[0012] The outdoor heat exchanger 204 exchanges heat between the outdoor air and the refrigerant, and functions as a condenser when the air conditioner 1 is in cooling operation, and functions as an evaporator when the air conditioner 1 is in heating operation. For example, during cooling operation, the refrigerant flows through the compressor 202, four-way valve 209, outdoor heat exchanger 204, outdoor expansion valve 206, and indoor unit 4 in this order, and the space to be air-conditioned is cooled. On the other hand, during heating operation, the refrigerant flows through the compressor 202, four-way valve 209, indoor unit 4, outdoor expansion valve 206, and outdoor heat exchanger 204 in this order, and the space to be air-conditioned is heated.

[0013] The outdoor blower 205 is disposed near the outdoor heat exchanger 204, draws in outdoor air (hereinafter referred to as outside air), and blows the air that has been heat exchanged in the outdoor heat exchanger 204 to the outside. The outside air drawn in by the outdoor blower 205 is blown against the outdoor heat exchanger 204. As a result, heat is exchanged between the outside air and the refrigerant flowing through the outdoor heat exchanger 204.

[0014] The outdoor expansion valve 206 reduces the pressure of, for example, the refrigerant (high-pressure liquid-phase refrigerant) flowing out from the outdoor heat exchanger 204 according to its opening degree, and changes it to a low-pressure gas-liquid two-phase refrigerant or liquid-phase refrigerant. The outdoor expansion valve 206 is a pressure reducer in which the amount of refrigerant throttling is adjusted by controlling the valve opening degree between a minimum opening degree and a maximum opening degree, for example, and is configured as a PMV (Pulse Motor Valve) in which the opening degree continuously changes according to the number of drive pulses supplied. The outdoor expansion valve 206 has its opening degree adjusted by the control unit 6, and provides the current opening degree (actual opening degree) value to the control unit 6 via a wired or wireless connection.

[0015] The second pressure detection unit (hereinafter referred to as the low pressure detection unit) 207 is disposed in a pipe (a part of the outdoor side pipe 201) between the four-way valve 209 and a gas-liquid separator (accumulator) 210 described later, and detects the pressure of the refrigerant sucked into the compressor 202. More specifically, the low pressure detection unit 207 detects the pressure (second pressure) of the low pressure gas-liquid two-phase refrigerant that flows through the pipe and is separated into gas and liquid in the gas-liquid separator 210. The low pressure detection unit 207 is, for example, a pressure sensor having a pressure-sensitive element disposed in the pipe to detect the second pressure. The low pressure detection unit 207 provides the detected value of the second pressure to the control unit 6 via a wired or wireless connection. The gas-liquid separator 210 separates the refrigerant into gas and liquid so that the compressor 202 does not compress the liquid phase refrigerant. A suction pipe 201a is connected to a refrigerant outlet of the gas-liquid separator 210, and the refrigerant separated into gas and liquid in the gas-liquid separator 210 is sucked through the suction pipe 201a into the suction port of the compressor 202.

[0016] The outdoor air temperature detection unit 208 detects the outdoor air temperature, which is the temperature of the air outside. The outdoor here is the outdoor space as opposed to the indoor space which is the space to be air-conditioned, such as an outdoor space in which the outdoor heat exchanger 204 and the outdoor blower 205 are installed. The outdoor air temperature detection unit 208 is, for example, a temperature sensor (thermistor) having a temperature sensing element disposed near the outdoor heat exchanger 204 to detect the outdoor air temperature. The outdoor air temperature detection unit 208 provides the detected outdoor air temperature value to the control unit 6 via wired or wireless communication.

[0017] The four-way valve 209 guides the refrigerant discharged from the compressor 202 to the condenser, that is, to the outdoor heat exchanger 204 during cooling, and to an indoor heat exchanger 402 of the indoor unit 4 described below during heating. The four-way valve 209 also guides the refrigerant returning to the compressor 202 from the evaporator, that is, the indoor heat exchanger 402 during cooling, and from the outdoor heat exchanger 204 during heating, to an accumulator 210.

[0018] The indoor unit 4 has, as main components, an indoor heat exchanger 402, an indoor blower 403, an indoor expansion valve 404, and the like.

[0019] The indoor heat exchanger 402 exchanges heat between the indoor air and the refrigerant, and functions as an evaporator when the air conditioner 1 is in cooling operation, and functions as a condenser when the air conditioner 1 is in heating operation. For example, during cooling operation, the refrigerant flows through the compressor 202, four-way valve 209, outdoor heat exchanger 204, outdoor expansion valve 206, indoor heat exchanger 402, and indoor expansion valve 404 in this order, and the space to be air-conditioned is cooled. On the other hand, during heating operation, the refrigerant flows through the compressor 202, four-way valve 209, indoor expansion valve 404, indoor heat exchanger 402, outdoor expansion valve 206, and outdoor heat exchanger 204 in this order, and the space to be air-conditioned is heated.

[0020] The indoor blower 403 is disposed near the indoor heat exchanger 402, sucks in air in the room to be conditioned (hereinafter referred to as indoor air), and blows the air that has been heat exchanged in the indoor heat exchanger 402 into the room. The indoor air sucked in by the indoor blower 403 is blown against the indoor heat exchanger 402. As a result, heat is exchanged between the indoor air and the refrigerant flowing through the indoor heat exchanger 402.

[0021] The indoor expansion valve 404 is a regulating valve capable of adjusting the flow rate of the refrigerant according to its opening. That is, the indoor expansion valve 404 adjusts the flow rate of the refrigerant flowing out of the indoor heat exchanger 402 during cooling, and adjusts the flow rate of the refrigerant flowing into the indoor heat exchanger 402 during heating. The indoor expansion valve 404 is a pressure reducer in which the amount of refrigerant throttled is adjusted by controlling the opening of the valve between a minimum opening and a maximum opening, for example, and is configured as a PMV (Pulse Motor Valve) whose opening changes continuously according to the number of drive pulses supplied. The opening of the indoor expansion valve 404 is adjusted by the control unit 6, and the value of the current opening (actual opening) is provided to the control unit 6 via a wired or wireless connection.

[0022] The control unit 6 controls the operation of the outdoor unit 2 and the indoor unit 4, and controls the operation of the air conditioner 1. The control unit 6 includes a CPU, a memory, a storage device (non-volatile memory), an input / output circuit, a timer, and the like, and executes predetermined arithmetic processing. For example, the control unit 6 reads various data through the input / output circuit, performs arithmetic processing with the CPU using a program read from the storage device to the memory, and controls the operation of the compressor 202, the high pressure detection unit 203, the outdoor expansion valve 206, the low pressure detection unit 207, the outdoor air temperature detection unit 208, and the indoor expansion valve 404, etc., based on the processing results. At that time, the control unit 6 transmits and receives control signals and data signals between them via wires or wirelessly. That is, the control unit 6 and each of the components to be controlled are electrically connected via wires or wirelessly.

[0023] In this embodiment, the control unit 6 has a refrigerant leakage detection unit 601 that detects leakage of the refrigerant from the pipes (the outdoor pipes 201 and the indoor pipes 401) that form a flow path through which the refrigerant flows. The refrigerant leakage detection unit 601 is configured as a program that causes a CPU to execute a predetermined calculation process for detecting leakage of the refrigerant, for example, and is stored in a storage device of the control unit 6 and read into the memory when executed.

[0024] In order to detect a refrigerant leak, the refrigerant leak detection unit 601 acquires the actual opening degree of the indoor expansion valve 404 and calculates the predicted opening degree of the indoor expansion valve 404 .

[0025] The actual opening of the indoor expansion valve 404 is the current opening of the indoor expansion valve 404, that is, the actual opening at that point in time. The refrigerant leakage detection unit 601 acquires the value of the actual opening from the indoor expansion valve 404. The acquired value of the actual opening is held in the memory of the control unit 6.

[0026] The predicted opening is a predicted opening as the current opening (actual opening) of the indoor expansion valve 404, that is, a predicted value of the actual opening, and is calculated using a predetermined parameter. The predetermined parameters are various values ​​in a case where it is assumed that the refrigerant is not leaking from the pipes (the outdoor pipe 201 and the indoor pipe 401) (hereinafter, referred to as an appropriate state). In this embodiment, for example, the following values ​​in the appropriate state, specifically, the rotation speed of the compressor 202, the first pressure (discharge pressure) and the second pressure of the refrigerant in the appropriate state, and the opening of the indoor expansion valve 404 are at least used as parameters. In other words, the predicted opening is the opening that the indoor expansion valve 404 should reach during the current operation of the air conditioner 1 in a case where it is in an appropriate state (assuming that the refrigerant is not leaking). The calculated value of the predicted opening is stored in a storage device (non-volatile memory) of the control unit 6, which is stored in the predicted opening storage unit 602 in the example shown in FIG. 1. The value of the predicted opening stored in the predicted opening storage unit 602 is read out to the memory of the control unit 6 as a parameter for determining whether or not there is a refrigerant leak.

[0027] The proper state is a state in which the air conditioner 1 starts operation, and after the cumulative time from the start exceeds a predetermined time, a predetermined condition is satisfied, and is an initial state on the premise that refrigerant is not leaking from the pipes (the outdoor pipe 201 and the indoor pipe 401). The predetermined time can be set arbitrarily depending on the environment in which the air conditioner 1 is installed, and is, for example, about 10 to 50 hours. The predetermined conditions may include, for example, that the degree of superheat (SH: Super Heat) is proper, that the outdoor air temperature is not extremely outside the operating range, and that the rotation speed of the compressor 202 is not extremely low, so that each state of the refrigeration cycle in the air conditioner 1 can be appropriately determined.

[0028] The refrigerant leakage detection unit 601 acquires the value of the rotation speed of the compressor 202 in the proper state from the compressor 202. The refrigerant leakage detection unit 601 acquires the value of the first pressure (discharge pressure) of the refrigerant in the proper state from the high pressure detection unit 203. The refrigerant leakage detection unit 601 acquires the value of the second pressure of the refrigerant in the proper state from the low pressure detection unit 207. Note that, as a parameter of the predicted opening degree, the values ​​(detected values) acquired from the high pressure detection unit 203 and the low pressure detection unit 207, that is, temperature values, instead of pressure values, may be used. In this case, it is possible to calculate a saturation temperature from the values ​​(detected values) acquired from the high pressure detection unit 203 and the low pressure detection unit 207, and use the calculated saturation temperature as a parameter. The refrigerant leakage detection unit 601 acquires the value of the opening degree of the indoor expansion valve 404 in the proper state from the indoor expansion valve 404. The acquired values ​​of the rotation speed of the compressor 202, the first pressure (discharge pressure) and second pressure of the refrigerant, and the opening degree of the indoor expansion valve 404 are held in the memory of the control unit 6.

[0029] For example, when the air conditioning apparatus 1 includes multiple indoor units 4, the refrigerant leakage detection unit 601 calculates the predicted opening as the total value of the predicted values ​​of the actual openings of the indoor expansion valves 404 included in each indoor unit 4, i.e., the multiple indoor expansion valves 404. In this case, however, the predicted opening may also be calculated as the average value of the predicted values ​​of the actual openings of the multiple indoor expansion valves 404.

[0030] The refrigerant leakage detection unit 601 detects refrigerant leakage by comparing the difference between the actual opening degree and the predicted opening degree of the indoor expansion valve 404 with a predetermined judgment threshold value. The judgment threshold value is a threshold value for judging whether or not refrigerant is leaking from the pipes (the outdoor pipe 201 and the indoor pipe 401), and in this embodiment, it is a value before correction described later, that is, an initial value. The judgment threshold value may be a fixed value set in advance, or may be a variable value that varies depending on the judgment of the presence or absence of refrigerant leakage. The judgment threshold value is held in the memory of the control unit 6, for example, or stored in a storage device (non-volatile memory), and is used as a parameter when judging the presence or absence of refrigerant leakage. For example, when the air conditioning device 1 includes multiple indoor units 4 and the predicted opening degree is calculated as the sum of the predicted values ​​of the actual opening degrees of each of the multiple indoor expansion valves 404, the actual opening degree when calculating the difference is the sum of the actual opening degrees of each of the multiple indoor expansion valves 404.

[0031] When detecting a refrigerant leak, the refrigerant leak detection unit 601 corrects the judgment threshold value according to a predetermined coefficient (hereinafter, referred to as a correction coefficient). The correction coefficient is a value determined by various requirements in an appropriate state. For example, the outdoor air temperature in an appropriate state can be used as the correction coefficient. In addition to this, for example, the capacity ratio of the indoor unit 4 to the outdoor unit 2 (hereinafter, simply referred to as a capacity ratio), the ratio of the number of indoor units 4 in operation when multiple indoor units 4 are provided (hereinafter, simply referred to as the ratio of the number of indoor units in operation), etc. can be applied as the correction coefficient, and in all cases, the detection value in the appropriate state is used. These correction coefficients are only examples, and in addition to the outdoor air temperature, capacity ratio, and ratio of the number of indoor units in operation in the appropriate state, it is possible to add a value determined by any requirement as a correction coefficient.

[0032] The outdoor air temperature is the temperature of air in an outdoor space where the outdoor heat exchanger 204 and the outdoor blower 205 are installed as described above, and is detected by the outdoor air temperature detection unit 208. The refrigerant leakage detection unit 601 acquires the value of the outdoor air temperature in an appropriate state from the outdoor air temperature detection unit 208. The acquired value of the outdoor air temperature is held in the memory of the control unit 6.

[0033] The capacity ratio is the ratio between the capacity value of the outdoor unit 2 and the capacity value of the indoor unit 4 equipped in the air conditioning apparatus 1. The capacity value is the rated capacity of heating and cooling expressed in kilowatts (kW), for example, and when there are multiple indoor units 4, it is the total value of the rated capacities of each. The refrigerant leakage detection unit 601 calculates the capacity ratio based on the capacity value of the outdoor unit 2 and the capacity value of the indoor unit 4 in an appropriate state. The calculated capacity ratio value is held in the memory of the control unit 6.

[0034] The ratio of the number of operating units is the ratio of the number of indoor units 4 in operation to the total number of indoor units 4 when multiple indoor units 4 are provided. Whether or not an indoor unit 4 is operating can be determined based on any condition, such as whether or not the indoor expansion valve 404 is open, or whether or not a user has selected operation via a remote control for the indoor unit 4. The refrigerant leakage detection unit 601 calculates the ratio of the number of operating units based on the number of indoor units 4 in operation in the appropriate state. The calculated value of the ratio of the number of operating units is held in the memory of the control unit 6.

[0035] The refrigerant leakage detection unit 601 detects a refrigerant leakage based on the actual opening and predicted opening of the indoor expansion valve 404 and the correction coefficient. When making such detection, the refrigerant leakage detection unit 601 calculates the following formula (1). (Actual opening) - (Predicted opening) > α × W × X × Y × Z … (1) In formula (1), the actual opening is the actual opening value of the indoor expansion valve 404 at the time of calculation of formula (1). The predicted opening is the predicted opening value stored in the predicted opening storage unit 602. α is the value of the judgment threshold, more precisely, the value of the judgment threshold before correction (initial value of the judgment threshold). W is the value of the correction coefficient by the input unit. X is the correction coefficient by the outdoor air temperature. Y is the value of the correction coefficient by the capacity ratio. Z is the value of the correction coefficient by the ratio of the number of operating units. The input unit inputs the correction coefficient for correcting the judgment threshold and gives it to the refrigerant leakage detection unit 601. In the example shown in FIG. 1, the input unit 603 is configured as any external input means capable of switching, operating, setting, etc. in the control unit 6, for example, a switch on a control board. However, the location of the input unit 603 is not particularly limited, and may be configured as an external input means such as an operation panel of the outdoor unit 2 or a remote control of the indoor unit 4.

[0036] If formula (1) is satisfied, the refrigerant leakage detection unit 601 determines that refrigerant is leaking from the piping (the outdoor piping 201 and the indoor piping 401). As a result, refrigerant leakage is detected based on the actual opening degree, the predicted opening degree, and the correction coefficient of the indoor expansion valve 404. On the other hand, if formula (1) is not satisfied, the refrigerant leakage detection unit 601 determines that refrigerant is not leaking from the piping (the outdoor piping 201 and the indoor piping 401). In this case, it is detected that refrigerant is not leaking based on the actual opening degree, the predicted opening degree, and the correction coefficient of the indoor expansion valve 404.

[0037] The correction coefficient according to the outside air temperature indicated by X in formula (1) will now be described. FIG. 2 is a diagram showing an example of the value of the correction coefficient according to the outside air temperature. The value of the correction coefficient according to the outside air temperature is stored in the storage device (non-volatile memory) of the control unit 6, for example, in a table format as shown in FIG. 2, in the correction coefficient storage unit 604 in the example shown in FIG. 1. However, the storage format is not limited to this. Each value of the correction coefficient according to the outside air temperature stored in the correction coefficient storage unit 604 is read into the memory of the control unit 6 as a parameter for correcting the determination threshold value when determining whether or not there is a refrigerant leak.

[0038] In the example shown in FIG. 2, the value (X) of the correction coefficient based on the outside air temperature (Tx) is set by two threshold values, a first reference temperature (Tx1) and a second reference temperature (Tx2). The second reference temperature is higher than the first reference temperature. As a result, the outside air temperature is divided into three temperature ranges: high, medium, and low. The value of the correction coefficient based on the outside air temperature is set to be smaller when the outside air temperature is in the standard state than when it is outside the standard state. In the example shown in FIG. 2, the standard state of the outside air temperature is when the outside air temperature is equal to or higher than the first reference temperature and equal to or lower than the second reference temperature (Tx1 ≤ Tx ≤ Tx2). That is, the correction coefficient when the outside air temperature is equal to or higher than the first reference temperature and equal to or lower than the second reference temperature is set to be smaller than either the correction coefficient when the outside air temperature is less than the first reference temperature (Tx < Tx1) and the correction coefficient when the outside air temperature exceeds the second reference temperature (Tx2 < Tx) (the relationship is as shown by "large" and "small" in FIG. 2).

[0039] Therefore, the refrigerant leakage detection unit 601 corrects the determination threshold according to the correction coefficient based on the outside air temperature so that the determination threshold is larger when the outside air temperature is less than the first reference temperature and when it exceeds the second reference temperature than when the outside air temperature is equal to or higher than the first reference temperature and equal to or lower than the second reference temperature. The first reference temperature and the second reference temperature may be set such that, for example, when the air conditioner 1 is in the cooling operation, a temperature range of about 35°C is included in the standard state of the outside air temperature, and when it is in the heating operation, a temperature range of about 7°C is included in the standard state of the outside air temperature. The correction coefficient based on the outside air temperature may be set to increase as the range in which the outside air temperature deviates from the standard state increases. Note that the number of threshold values (reference temperatures) for dividing the outside air temperature may be three or more, or may be one. When the number of threshold values (reference temperatures) for dividing the outside air temperature is one, the state in which the outside air temperature is the reference temperature corresponding to the threshold value may be set as the standard state.

[0040] The correction coefficient based on the ability ratio indicated by Y in Equation (1) will be described. FIG. 3 is a diagram showing an example of the value of the correction coefficient based on the ability ratio. The value of the correction coefficient based on the ability ratio is stored in the storage device (non-volatile memory) of the control unit 6 in a table format as shown in FIG. 3, for example. In the example shown in FIG. 1, it is stored in the correction coefficient storage unit 604. However, the storage format is not limited to this. Each value of the correction coefficient based on the ability ratio stored in the correction coefficient storage unit 604 is read into the memory of the control unit 6 as a parameter when correcting the determination threshold at the time of determining the presence or absence of refrigerant leakage.

[0041] In the example shown in FIG. 3, the value (Y) of the correction coefficient based on the ability ratio (Ry) is set by two threshold values, the first reference ability ratio (Ry1) and the second reference ability ratio (Ry2). The second reference ability ratio is larger than the first reference ability ratio. As a result, the ability ratio is divided into three ratio ranges: high, medium, and low. The correction coefficient when the ability ratio is in the standard state is set to be smaller than the correction coefficient when the ability ratio is in a state other than the standard state. In the example shown in FIG. 3, the standard state of the ability ratio is when the ability ratio is greater than or equal to the first reference ability ratio and less than or equal to the second reference ability ratio (Ry1 ≦ Ry ≦ Ry2). That is, the correction coefficient when the ability ratio is greater than or equal to the first reference ability ratio and less than or equal to the second reference ability ratio is set to be smaller than either the correction coefficient when the ability ratio is less than the first reference ability ratio (Ry < Ry1) and the correction coefficient when the ability ratio exceeds the second reference ability ratio (Ry2 < Ry) (it is a relationship as shown by "large" and "small" in FIG. 3).

[0042] Therefore, the refrigerant leakage detection unit 601 corrects the judgment threshold according to the correction coefficient by the capacity ratio so that the judgment threshold is larger when the capacity ratio is less than the first standard capacity ratio and exceeds the second standard capacity ratio than when the capacity ratio is equal to or greater than the first standard capacity ratio and equal to or less than the second standard capacity ratio. The first standard capacity ratio and the second standard capacity ratio may be set so that the standard state of the capacity ratio includes, for example, 1, that is, the capacity value of the outdoor unit 2: the capacity value of the indoor unit 4 is 1:1. The correction coefficient by the capacity ratio may be set so that the larger the capacity ratio is, the greater the range in which the capacity ratio deviates from the standard state. The number of thresholds (standard capacity ratios) for classifying the capacity ratios may be three or more, or may be one. If the number of thresholds (standard capacity ratios) for classifying the capacity ratios is one, the standard state may be a state in which the capacity ratio is the standard capacity ratio corresponding to the threshold.

[0043] The correction coefficient based on the ratio of the number of operating units indicated by Z in formula (1) will now be described. FIG. 4 is a diagram showing an example of the value of the correction coefficient based on the ratio of the number of operating units. The value of the correction coefficient based on the ratio of the number of operating units is stored in the storage device (non-volatile memory) of the control unit 6 in a table format as shown in FIG. 4, for example, or in the correction coefficient storage unit 604 in the example shown in FIG. 1. However, the storage format is not limited to this. Each value of the correction coefficient based on the ratio of the number of operating units stored in the correction coefficient storage unit 604 is read into the memory of the control unit 6 as a parameter for correcting the determination threshold value when determining the presence or absence of a refrigerant leak.

[0044] In the example shown in FIG. 4, the value (Z) of the correction coefficient based on the number of operating units ratio (Rz) is set by two threshold values, a first reference number of operating units ratio (Rz1) and a second reference number of operating units ratio (Rz2). The second reference number of operating units ratio is smaller than the first reference number of operating units ratio. Thereby, the number of operating units ratio is divided into three ratio ranges: high, medium, and low. The correction coefficient when the number of operating units ratio is in the standard state is set to be smaller than the correction coefficient when the number of operating units ratio is outside the standard state. In the example shown in FIG. 4, the standard state of the number of operating units ratio is when the number of operating units ratio is greater than or equal to the first reference number of operating units ratio (Rz1≦Rz). Here, the correction coefficient is set to increase in the order of when the number of operating units ratio is greater than or equal to the first reference number of operating units ratio (Rz1≦Rz), when it is less than the first reference number of operating units ratio and greater than or equal to the second reference number of operating units ratio (Rz2≦Rz<Rz1), and when it is less than the second reference number of operating units ratio (Rz<Rz2) (the relationship shown as "small", "medium", "large" in FIG. 4).

[0045] Therefore, the refrigerant leakage detection unit 601 corrects the determination threshold according to the correction coefficient based on the number of operating units ratio so that the determination threshold increases in the order of when the number of operating units ratio is greater than or equal to the first reference number of operating units ratio, when it is less than the first reference number of operating units ratio and greater than or equal to the second reference number of operating units ratio, and when it is less than the second reference number of operating units ratio. The first reference number of operating units ratio and the second reference number of operating units ratio may be set with the standard state of the number of operating units ratio being 100% (the state where all indoor units 4 are operating). The correction coefficient based on the number of operating units ratio may be set to increase as the range in which the number of operating units ratio deviates from the standard state increases. Note that the number of threshold values (reference number of operating units ratio) for dividing the number of operating units ratio may be three or more, or may be one. When the number of threshold values (reference number of operating units ratio) for dividing the number of operating units ratio is one, the state where the number of operating units ratio is the reference number of operating units ratio corresponding to the threshold value may be set as the standard state.

[0046] The correction coefficient by the input unit 603 indicated by W in formula (1) will now be described. The value of the correction coefficient by the input unit 603 is input by, for example, a user switching, operating, or setting a switch on the control board of the control unit 6, an operation panel of the outdoor unit 2, or a remote control for the indoor unit 4. The input correction coefficient value is stored, for example, in a storage device (non-volatile memory) of the control unit 6, such as the correction coefficient storage unit 604 in the example shown in FIG. 1. When correcting the determination threshold value when determining whether or not there is a refrigerant leak, the refrigerant leak detection unit 601 reads out the correction coefficient by the input unit 603 from the correction coefficient storage unit 604 as a parameter into the memory of the control unit 6. As a result, the correction coefficient input by the input unit 603 is provided to the refrigerant leak detection unit 601.

[0047] The correction coefficient (W) by the input unit 603 is set arbitrarily depending on, for example, the environment in which the air conditioning device 1 is installed, and is used separately from the correction coefficient based on the outside air temperature (X), the correction coefficient based on the capacity ratio (Y), and the correction coefficient based on the ratio of the number of operating units (Z), in order to more flexibly correct the judgment threshold value.

[0048] In this embodiment, the timing at which the judgment threshold is corrected is assumed to be a predetermined timing at which the air conditioner 1 continues to operate from the appropriate state, that is, after the parameters for calculating the predicted opening of the indoor expansion valve 404 are acquired. However, as a modified example, the correction timing of the judgment threshold may be varied according to a correction coefficient. For example, when the parameters for calculating the predicted opening of the indoor expansion valve 404 in the appropriate state are acquired, the judgment threshold is corrected according to a correction coefficient based on the capacity ratio and a correction coefficient based on the ratio of the number of operating units. Then, when determining whether or not refrigerant is leaking from the pipes (the outdoor pipes 201 and the indoor pipes 401) that constitute the flow path through which the refrigerant flows, the judgment threshold is corrected according to a correction coefficient based on the outdoor air temperature.

[0049] As described above, according to this embodiment and the modified example, it is possible to detect refrigerant leakage from the pipes (the outdoor pipes 201 and the indoor pipes 401) based on the difference between the actual opening and the predicted opening of the indoor expansion valve 404. At that time, the determination threshold for determining the presence or absence of refrigerant leakage can be corrected by a predetermined correction coefficient.

[0050] For example, when the outdoor air temperature deviates from the rated temperature of the air conditioner 1 in the proper state, the accuracy of the predicted opening degree of the indoor expansion valve 404 may deteriorate depending on the extent of the deviation. Even in this case, the presence or absence of refrigerant leakage can be accurately determined by correcting the judgment threshold value according to the correction coefficient for the outdoor air temperature. That is, according to this embodiment, the value of the correction coefficient for the outdoor air temperature is set smaller when the outdoor air temperature is in a standard state (not less than the first reference temperature and not more than the second reference temperature) than when the outdoor air temperature is in a non-standard state. Therefore, the judgment threshold value can be corrected according to the correction coefficient for the outdoor air temperature so that the judgment threshold value is larger when the outdoor air temperature is in a non-standard state than when the outdoor air temperature is in a standard state. This makes it possible to improve the accuracy of refrigerant leakage detection according to the outdoor air temperature.

[0051] Furthermore, the judgment threshold can be corrected using a correction coefficient based on the capacity ratio. For example, the value of the correction coefficient based on the capacity ratio is set smaller when the capacity ratio is in a standard state (not less than the first standard capacity ratio and not more than the second standard capacity ratio) than when the capacity ratio is in a non-standard state. Therefore, the judgment threshold can be corrected according to the correction coefficient based on the capacity ratio so that the judgment threshold is larger when the capacity ratio is in a non-standard state than when the capacity ratio is in the standard state. This makes it possible to improve the accuracy of refrigerant leakage detection by the capacity ratio as well.

[0052] Furthermore, the judgment threshold can be corrected using a correction coefficient based on the ratio of the number of operating units. For example, the value of the correction coefficient based on the ratio of the number of operating units is set smaller when the ratio of the number of operating units is in a standard state (exceeding a first reference ratio of the number of operating units) than when the ratio of the number of operating units is other than the standard state. Therefore, the judgment threshold can be corrected according to the correction coefficient based on the ratio of the number of operating units so that the judgment threshold is larger when the ratio of the number of operating units is other than the standard state than when the ratio of the number of operating units is in the standard state. This makes it possible to improve the accuracy of refrigerant leakage detection based on the ratio of the number of operating units as well.

[0053] In addition, the judgment threshold can be corrected using a correction coefficient from the input unit 603. For example, the value of the correction coefficient from the input unit 603 is set arbitrarily depending on the environment in which the air conditioning device 1 is installed, and can be used separately from the correction coefficients based on the outside air temperature, the capacity ratio, and the ratio of the number of operating units. This allows the judgment threshold to be corrected more flexibly.

[0054] In this way, according to this embodiment and the modified example, it is possible to increase the degree of freedom in correcting the judgment threshold. For example, the judgment threshold can be more appropriately corrected depending on the environment in which the air conditioning device 1 is installed. As a result, it becomes possible to accurately detect refrigerant leakage even in various environments and installation conditions.

[0055] Although the embodiment (including the modified examples) of the present invention has been described above, the embodiment is presented as an example and is not intended to limit the scope of the invention. Such a novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0056] 1...air conditioning apparatus, 2...outdoor unit, 4...indoor unit, 6...control unit, 201...outdoor side piping, 201a...suction pipe, 201b...discharge pipe, 202...compressor, 203...first pressure detection unit (high pressure detection unit), 204...outdoor heat exchanger, 205...outdoor blower, 206...outdoor expansion valve, 207...second pressure detection unit (low pressure detection unit), 208...outdoor temperature detection unit, 209...four-way valve, 210...gas-liquid separator (accumulator), 401...indoor side piping, 402...indoor heat exchanger, 403...indoor blower, 404...indoor expansion valve, 601...refrigerant leakage detection unit, 602...predicted opening degree memory unit, 603...input unit, 604...correction coefficient memory unit.

Claims

1. an outdoor unit having a compressor that draws in a refrigerant, compresses it, and discharges it, an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant, an outdoor blower that draws in the outdoor air and blows the air that has been heat exchanged in the outdoor heat exchanger out to the outside, a first pressure detection unit that detects a first pressure of the refrigerant discharged from the compressor, a second pressure detection unit that detects a second pressure of the refrigerant drawn into the compressor, and an outdoor air temperature detection unit that detects an outdoor air temperature, which is the temperature of the air outside the room; at least one indoor unit including an indoor heat exchanger that exchanges heat between indoor air and the refrigerant, an indoor blower that draws in indoor air and blows the air that has been heat exchanged by the indoor heat exchanger into the room, and an indoor expansion valve that can adjust the flow rate of the refrigerant according to its opening degree; A control unit for controlling the operation of the outdoor unit and the indoor unit, An air conditioning apparatus in which the outdoor unit and the indoor unit are connected by a pipe through which the refrigerant flows, the control unit has a refrigerant leakage detection unit that acquires an actual opening, which is a current opening of the indoor expansion valve, calculates a predicted opening that is predicted as the current opening of the indoor expansion valve based at least on the rotation speed of the compressor, the first pressure and the second pressure of the refrigerant, and the opening of the indoor expansion valve on the assumption that the refrigerant is not leaking from the piping, and compares a difference between the actual opening and the predicted opening with a judgment threshold value that can be corrected from an initial value to detect leakage of the refrigerant from the piping; the refrigerant leakage detection unit corrects the determination threshold by multiplying the initial value by a correction coefficient based on the outside air temperature so that the determination threshold is larger when the outside air temperature is less than the first reference temperature and exceeds the second reference temperature than when the outside air temperature is equal to or greater than the first reference temperature and equal to or less than a second reference temperature that is greater than the first reference temperature; A ratio between the rated capacity of the outdoor unit and the rated capacity of the indoor unit is calculated as a capacity ratio, and the determination threshold is corrected by multiplying the initial value by a correction coefficient based on the capacity ratio so that the determination threshold is larger when the capacity ratio is less than the first standard capacity ratio or exceeds the second standard capacity ratio than when the capacity ratio is equal to or greater than a first standard capacity ratio and equal to or less than a second standard capacity ratio that is greater than the first standard capacity ratio. Air conditioning equipment.

2. an outdoor unit having a compressor that draws in a refrigerant, compresses it, and discharges it, an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant, an outdoor blower that draws in the outdoor air and blows the air that has been heat exchanged in the outdoor heat exchanger out to the outside, a first pressure detection unit that detects a first pressure of the refrigerant discharged from the compressor, a second pressure detection unit that detects a second pressure of the refrigerant drawn into the compressor, and an outdoor air temperature detection unit that detects an outdoor air temperature, which is the temperature of the air outside the room; at least one indoor unit including an indoor heat exchanger that exchanges heat between indoor air and the refrigerant, an indoor blower that draws in indoor air and blows the air that has been heat exchanged by the indoor heat exchanger into the room, and an indoor expansion valve that can adjust the flow rate of the refrigerant according to its opening degree; A control unit for controlling the operation of the outdoor unit and the indoor unit, An air conditioning apparatus in which the outdoor unit and the indoor unit are connected by a pipe through which the refrigerant flows, the control unit has a refrigerant leakage detection unit that acquires an actual opening, which is a current opening of the indoor expansion valve, calculates a predicted opening that is predicted as the current opening of the indoor expansion valve based at least on the rotation speed of the compressor, the first pressure and the second pressure of the refrigerant, and the opening of the indoor expansion valve on the assumption that the refrigerant is not leaking from the piping, and compares a difference between the actual opening and the predicted opening with a judgment threshold value that can be corrected from an initial value to detect leakage of the refrigerant from the piping; the refrigerant leakage detection unit corrects the determination threshold by multiplying the initial value by a correction coefficient based on the outside air temperature so that the determination threshold is larger when the outside air temperature is less than the first reference temperature and exceeds the second reference temperature than when the outside air temperature is equal to or greater than the first reference temperature and equal to or less than a second reference temperature that is greater than the first reference temperature; a ratio between a rated capacity of the outdoor unit and a rated capacity of the indoor unit is calculated as a capacity ratio, and the judgment threshold is corrected by multiplying the initial value by a correction coefficient based on the capacity ratio so that the judgment threshold is larger when the capacity ratio is less than the first standard capacity ratio or exceeds the second standard capacity ratio than when the capacity ratio is equal to or greater than a first standard capacity ratio and equal to or less than a second standard capacity ratio that is greater than the first standard capacity ratio; The timing for correcting the determination threshold is varied according to each of a plurality of correction coefficients. Air conditioning equipment.

Images