Air conditioner

Abstract

An air conditioner includes a refrigerant circuit formed by connecting an indoor unit to an outdoor unit via refrigerant piping. The outdoor unit includes a compressor, an outdoor heat exchanger, and an expansion valve. The indoor unit includes an indoor heat exchanger. The refrigerant circuit is filled with a preset amount of refrigerant. The air conditioner includes: an acquisition unit that periodically acquires operating status quantities during air conditioner operation; a storage unit for storing the acquired operating status quantities; a calculation model that uses the operating status quantities to calculate the residual refrigerant amount remaining in the refrigerant circuit; a detection unit for detecting a first operating status quantity or a second operating status quantity from the storage unit, wherein the first operating status quantity is the operating status quantity under a first stability condition of the refrigerant circuit, and the second operating status quantity is the operating status quantity under a second stability condition different from the first stability condition; and a control unit that uses the calculation model and the detected operating status quantities to calculate the residual refrigerant amount in the refrigerant circuit. The air conditioner can calculate the residual refrigerant amount in the refrigerant circuit even during actual operation.

Description

Technical Field

[0001] This invention relates to air conditioners. Background Technology

[0002] An air conditioner has been proposed that uses an operating state quantity detectable in the refrigerant circuit to determine the refrigerant dosage (e.g., Patent Document 1). In Patent Document 1, for example, to ensure that only liquid refrigerant exists in the refrigerant flowing through the liquid line of the refrigerant circuit during the refrigeration cycle (preventing the absence of gaseous refrigerant), the refrigerant dosage is determined using the refrigerant subcooling at the condenser outlet under the condition that the refrigerant superheat at the evaporator outlet or the evaporator pressure is adjusted (hereinafter referred to as the default state).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2006-23072 Summary of the Invention

[0004] When the air conditioner is actually running, it is difficult to achieve the default state that is a prerequisite for Patent Document 1, making it difficult to calculate the amount of refrigerant.

[0005] The present invention is proposed in view of the above-mentioned problems, and its purpose is to provide an air conditioner that can calculate the amount of refrigerant remaining in the refrigerant circuit when the air conditioner is actually in operation.

[0006] An air conditioner has a refrigerant circuit formed by connecting an indoor unit to an outdoor unit via refrigerant piping. The outdoor unit has a compressor, an outdoor heat exchanger, and an expansion valve. The indoor unit has an indoor heat exchanger. The refrigerant circuit is filled with a preset amount of refrigerant. The air conditioner includes: an acquisition unit, a storage unit, a calculation model, a detection unit, and a control unit. The acquisition unit periodically acquires operating status quantities during the operation of the air conditioner. The storage unit stores the operating status quantities acquired by the acquisition unit. The calculation model uses the operating status quantities to calculate the residual refrigerant quantity remaining in the refrigerant circuit. The detection unit detects a first operating status quantity or a second operating status quantity from the storage unit. The first operating status quantity is the operating status quantity under a first stability condition of the refrigerant circuit, and the second operating status quantity is the operating status quantity under a second stability condition different from the first stability condition. The control unit uses the calculation model and the operating status quantity detected by the detection unit to calculate the residual refrigerant quantity in the refrigerant circuit.

[0007] On the one hand, even when the air conditioner is actually running, the amount of residual refrigerant in the refrigerant circuit can be estimated. Attached Figure Description

[0008] Figure 1This is an explanatory diagram illustrating an example of an air conditioner according to this embodiment.

[0009] Figure 2 This is an illustrative diagram showing an example of an outdoor unit and an indoor unit.

[0010] Figure 3 This is a block diagram illustrating an example of the control circuitry for an outdoor unit.

[0011] Figure 4 It is a Morrill diagram that represents the state of refrigerant changes in an air conditioner.

[0012] Figure 5 This is a flowchart illustrating an example of a processing action involving a control circuit that performs an acquisition process.

[0013] Figure 6 This is a flowchart illustrating an example of the processing actions of a control circuit involved in detection processing.

[0014] Figure 7 This is a flowchart illustrating an example of the processing actions of a control circuit involved in calculation processing.

[0015] Figure 8 This is an explanatory diagram illustrating an example of the air conditioning system of Embodiment 2. Detailed Implementation

[0016] The embodiments of the air conditioner, etc., disclosed in this application will now be described in detail with reference to the accompanying drawings. However, the disclosed technology is not limited to these embodiments. Furthermore, the various embodiments shown below can be appropriately modified within a reasonable scope.

[0017] Example 1

[0018] Air conditioner structure

[0019] Figure 1 This is an explanatory diagram showing an example of the air conditioner 1 in this embodiment. Figure 1 The air conditioner 1 shown is, for example, a household air conditioner with one outdoor unit 2 and one indoor unit 3. The outdoor unit 2 is connected to the indoor unit 3 via a liquid pipe 4 and a gas pipe 5. Furthermore, the outdoor unit 2 and the indoor unit 3 are connected via refrigerant piping, such as the liquid pipe 4 and the gas pipe 5, thereby forming the refrigerant circuit 6 of the air conditioner 1.

[0020] outdoor unit structure

[0021] Figure 2This is an explanatory diagram showing an example of outdoor unit 2 and indoor unit 3. Outdoor unit 2 includes: compressor 11, four-way valve 12, outdoor heat exchanger 13, expansion valve 14, receiver 15, outdoor fan 16, and control circuit 17. Using the compressor 11, four-way valve 12, outdoor heat exchanger 13, expansion valve 14, and receiver 15, they are interconnected by various refrigerant piping as described in detail below, thereby forming an outdoor refrigerant circuit as part of refrigerant circuit 6.

[0022] The compressor 11 is, for example, a high-pressure container type variable capacity compressor that can change its operating capacity by being driven by an electric motor (not shown) whose speed is controlled by an inverter. The refrigerant discharge side of the compressor 11 is connected to the first valve port 12A of the four-way valve 12 via the discharge pipe 21. Furthermore, the refrigerant suction side of the compressor 11 is connected to the refrigerant discharge side of the receiver 15 via the suction pipe 22.

[0023] The four-way valve 12 is a valve used to switch the refrigerant flow direction in the refrigerant circuit 6, and it has a first valve port 12A to a fourth valve port 12D. The first valve port 12A is connected to the refrigerant discharge side of the compressor 11 via the discharge pipe 21. The second valve port 12B is connected to one side of the refrigerant inlet / outlet of the outdoor heat exchanger 13 (corresponding to the first outdoor heat exchange port 13A described later) via the outdoor refrigerant pipe 23. The third valve port 12C is connected to the refrigerant inlet side of the receiver 15 via the outdoor refrigerant pipe 26. Furthermore, the fourth valve port 12D is connected to the indoor heat exchanger 51 via the outdoor gas pipe 24.

[0024] The outdoor heat exchanger 13 exchanges heat between the refrigerant and the outside air drawn into the outdoor unit 2 by the rotation of the outdoor unit fan 16. The outdoor heat exchanger 13 has: a first outdoor heat exchange port 13A serving as a refrigerant inlet / outlet on one side, a second outdoor heat exchange port 13B serving as a refrigerant inlet / outlet on the other side, and an outdoor heat exchange intermediate section 13C connecting the first outdoor heat exchange port 13A and the second outdoor heat exchange port 13B. The first outdoor heat exchange port 13A is connected to the second valve port 12B of the four-way valve 12 via an outdoor refrigerant pipe 23. The second outdoor heat exchange port 13B is connected to the expansion valve 14 via an outdoor liquid pipe 25. The outdoor heat exchange intermediate section 13C is connected to the first outdoor heat exchange port 13A and the second outdoor heat exchange port 13B. The outdoor heat exchanger 13 functions as a condenser during cooling operation of the air conditioner 1 and as an evaporator during heating operation of the air conditioner 1.

[0025] Expansion valve 14, located on outdoor liquid line 25, is an electronic expansion valve driven by a pulse motor (not shown). Expansion valve 14 adjusts its opening degree according to the number of pulses supplied by the pulse motor, thereby adjusting the amount of refrigerant flowing from expansion valve 14 into refrigerant circuit 6 (the amount of refrigerant flowing from outdoor heat exchanger 13 into indoor heat exchanger 51, or from indoor heat exchanger 51 into outdoor heat exchanger 13). The opening degree of expansion valve 14 is adjusted so that the refrigerant discharge temperature of compressor 11 reaches a preset temperature, i.e., the target discharge temperature.

[0026] The refrigerant inflow side of the receiver 15 is connected to the third port 12C of the four-way valve 12 via the outdoor refrigerant pipe 26. Furthermore, the refrigerant outflow side of the receiver 15 is connected to the refrigerant inflow side of the compressor 11 via the suction pipe 22. The receiver 15 separates the refrigerant flowing into it from the outdoor refrigerant pipe 26 into gaseous and liquid refrigerant, thus allowing only gaseous refrigerant to be drawn into the compressor 11.

[0027] The outdoor unit fan 16, made of resin material, is positioned near the outdoor heat exchanger 13. Based on the rotation of a fan motor (not shown), the outdoor unit fan 16 draws outside air into the interior of the outdoor unit 2 through an air intake (not shown) and discharges the outside air, which has exchanged heat with the refrigerant in the outdoor heat exchanger 13, to the outside of the outdoor unit 2 through an exhaust (not shown).

[0028] In addition, the outdoor unit 2 is equipped with multiple sensors. A discharge temperature sensor 31 is installed on the discharge pipe 21 to detect the temperature of the refrigerant discharged from the compressor 11, i.e., the refrigerant discharge temperature. An outdoor heat exchange outlet sensor 32 is installed on the outdoor liquid pipe 25 between the outdoor heat exchanger 13 and the expansion valve 14 to detect the temperature of the refrigerant flowing into or out of the second outdoor heat exchange outlet 13B. Furthermore, an external air temperature sensor 33 is installed near the air intake (not shown) of the outdoor unit 2 to detect the temperature of the external air flowing into the outdoor unit 2, i.e., the external air temperature.

[0029] Control circuit 17 receives instructions from control circuit 18 of indoor unit 3 (described later) to control outdoor unit 2. Control circuit 17 of outdoor unit 2 includes: a communication unit (not shown), a storage unit, and a control unit. The communication unit is a communication interface for communicating with communication unit 41 of indoor unit 3 (described later). The storage unit is, for example, a flash memory, used to store the control program of outdoor unit 2, operating status quantities such as detection values ​​corresponding to detection signals from various sensors, the drive status of compressor 11 and outdoor unit fan 16, and the rated capacity of outdoor unit 2 and the required capacity of each indoor unit 3.

[0030] Indoor unit structure

[0031] like Figure 2 As shown, the indoor unit 3 includes: an indoor heat exchanger 51, a gas pipe connection 52, a liquid pipe connection 53, an indoor unit fan 54, and a control circuit 18. The indoor heat exchanger 51, the gas pipe connection 52, and the liquid pipe connection 53 are connected to each other through refrigerant piping described later, thereby forming an indoor unit refrigerant circuit as part of the refrigerant circuit 6.

[0032] The indoor heat exchanger 51 facilitates heat exchange between the refrigerant and indoor air drawn into the indoor unit 3 through an air intake (not shown) by the rotation of the indoor unit fan 54. The indoor heat exchanger 51 includes a first indoor heat exchange port 51A serving as a refrigerant inlet / outlet on one side, a second indoor heat exchange port 51B serving as a refrigerant inlet / outlet on the other side, and an indoor heat exchange intermediate section 51C connecting the first indoor heat exchange port 51A and the second indoor heat exchange port 51B. The first indoor heat exchange port 51A is connected to a gas pipe connection 52 via an indoor gas pipe 56. The second indoor heat exchange port 51B is connected to a liquid pipe connection 53 via an indoor liquid pipe 57. The indoor heat exchange intermediate section 51C is connected to both the first indoor heat exchange port 51A and the second indoor heat exchange port 51B. The indoor heat exchanger 51 functions as a condenser during heating operation of the air conditioner 1 and as an evaporator during cooling operation of the air conditioner 1.

[0033] The indoor unit fan 54, made of resin material, is positioned near the indoor heat exchanger 51. The indoor unit fan 54 is driven to rotate by a fan motor (not shown), thereby drawing indoor air into the interior of the indoor unit 3 through an air intake (not shown) and discharging the indoor air, which has undergone heat exchange with the refrigerant in the indoor heat exchanger 51, out of the room through an exhaust (not shown).

[0034] Various sensors are installed in the indoor unit 3. The indoor heat exchange intermediate section 51C is equipped with an indoor heat exchange intermediate sensor 58, which is used to detect the temperature of the refrigerant flowing through the indoor heat exchange intermediate section 51C in the heat exchanger temperature, that is, the indoor heat exchange intermediate temperature.

[0035] The control circuit 18 is used to control the entire air conditioner 1. Figure 3This is a block diagram illustrating an example of the control circuit 18 of the indoor unit 3. The control circuit 18 includes a communication unit 41, an acquisition unit 42, a detection unit 43, a storage unit 44, and a control unit 45. The communication unit 41 is a communication interface for communicating with the communication unit of the outdoor unit 2. The acquisition unit 42 is used to acquire operating status quantities such as detection values ​​corresponding to detection signals from the various sensors. The storage unit 44 is, for example, a flash memory, used to store the control program of the indoor unit 3, operating status quantities such as detection values ​​corresponding to detection signals from various sensors, the drive status of the indoor unit fan 54, operating information sent from the outdoor unit 2 (e.g., including compressor 11 start / stop information, outdoor unit fan 16 drive status, etc.), and the rated capacity of the outdoor unit 2 and the required capacity of each indoor unit 3, etc.

[0036] The storage unit 44 includes an operating state quantity memory 61, a first operating state quantity memory 61A, and a second operating state quantity memory 61B. The operating state quantity memory 61 stores all operating state quantities acquired by the acquisition unit 42. These operating state quantities are, for example, during cooling operation, the compressor 11 speed, the opening degree of the expansion valve 14, the refrigerant discharge temperature of the compressor 11, the outdoor heat exchange outlet temperature, and the outdoor air temperature; or, for example, during heating operation, the compressor 11 speed, the opening degree of the expansion valve 14, the refrigerant discharge temperature of the compressor 11, and the indoor heat exchange intermediate temperature.

[0037] The first operating state quantity memory 61A stores the first operating state quantity. The first operating state quantity represents the operating state of the air conditioner under the following conditions: the high or low pressure values ​​of the refrigerant circuit 6 are stable, and the refrigerant circulates stably within the refrigerant circuit 6, satisfying a first stability condition. The first stability condition is that the fluctuation of the compressor 11 speed is within a first preset range for a first preset period or more, and the absolute value of the difference between the refrigerant discharge temperature of the compressor 11 and the target discharge temperature is below a preset value for a first preset period or more. For example, the first operating state quantity is obtained when, 8 minutes after the compressor 11 starts, the fluctuation of the compressor 11 speed is within ±1 rpm for 5 minutes, and the absolute value of the difference between the refrigerant discharge temperature of the compressor 11 and the target discharge temperature is within ±2°C for 5 minutes.

[0038] The second operating state quantity memory 61B stores the second operating state quantity. The second operating state quantity represents the operating state of the air conditioner during operation, where the refrigerant is circulating stably within the refrigerant circuit 6, and a second stable condition differs from the first stable condition. The second stable condition is a state where the compressor 11 speed fluctuation is within a second preset range, lasting for a period longer than a first preset period or for a period longer than a second preset period, where the second preset range exceeds the first preset range. For example, the second operating state quantity is obtained when, 8 minutes after the compressor 11 starts, the compressor 11 speed fluctuation is within ±5 rpm for 12 minutes. Furthermore, the second stable condition allows for further fluctuation in compressor 11 speed compared to the first stable condition; therefore, the deviation of the second operating state quantity obtained under the second stable condition is greater than that of the first operating state quantity obtained under the first stable condition.

[0039] The detection unit 43 detects a first operating state quantity from the operating state quantities stored in the operating state quantity memory 61, and stores the detected first operating state quantity in the first operating state quantity memory 61A. Furthermore, the detection unit 43 detects a second operating state quantity from the operating state quantities stored in the operating state quantity memory 61, and stores the detected second operating state quantity in the second operating state quantity memory 61B.

[0040] Furthermore, the storage unit 44 stores calculation models for estimating the residual refrigerant charge remaining in the refrigerant circuit 6. The calculation models include a refrigeration calculation model 62A and a heating calculation model 62B. The refrigeration calculation model 62A is used to calculate the residual refrigerant charge in the refrigerant circuit 6 during refrigeration operation. Similarly, the heating calculation model 62B is used to calculate the residual refrigerant charge in the refrigerant circuit 6 during heating operation.

[0041] The control unit 45 periodically acquires the detection values ​​of various sensors (e.g., once every 30 seconds). Based on this input information, the control unit 45 controls the entire air conditioner 1. Furthermore, the control unit 45 uses the aforementioned calculation models to calculate the remaining refrigerant charge.

[0042] Furthermore, the control unit 45 counts the number of detections of the first operating state quantity within a preset period. When the number of detections of the first operating state quantity is greater than or equal to a preset number, it uses the first operating state quantity and each calculation model to calculate the remaining refrigerant charge in the refrigerant circuit 6. If the number of detections of the first operating state quantity within the preset period is less than the preset number, the control unit 45 uses the second operating state quantity and each calculation model to calculate the remaining refrigerant charge in the refrigerant circuit 6. If, within a preset period, for example, the number of detections of the first operating state quantity in a day is a preset number, for example, 50 or more, the control unit 45 uses the first operating state quantity and each calculation model to calculate the remaining refrigerant charge. Furthermore, if the number of detections of the first operating state quantity in a day is less than 50, the control unit 45 uses the second operating state quantity and each calculation model to calculate the remaining refrigerant charge.

[0043] At a preset time of day, such as 1:00 AM, the control unit 45 uses either a first operating status quantity or a second operating status quantity acquired over the previous 24 hours to calculate the residual refrigerant charge in the refrigerant circuit 6 for the previous day. When the number of first operating status quantities detected exceeds a preset number, the residual refrigerant charge is calculated using the acquired first operating status quantity and the calculation model. When the number of first operating status quantities detected is less than the preset number, the residual refrigerant charge is calculated using the acquired second operating status quantity and the calculation model. Furthermore, the specific method for calculating the residual refrigerant charge for the day will be detailed later.

[0044] Operation of the refrigerant circuit

[0045] Next, the flow of refrigerant in the refrigerant circuit 6 and the operation of each part of the air conditioner 1 during air conditioning operation in this embodiment will be explained.

[0046] When the air conditioner 1 is in heating mode, the four-way valve 12 is switched to connect the first valve port 12A with the fourth valve port 12D, and the second valve port 12B with the third valve port 12C. Figure 2 (The state is shown by the solid line in the middle). Thus, the refrigerant circuit 6 is formed as a heating cycle where the indoor heat exchanger 51 functions as a condenser and the outdoor heat exchanger 13 functions as an evaporator. Furthermore, for ease of explanation, by... Figure 2 The solid arrows shown indicate the direction of refrigerant flow during heating operation.

[0047] When the refrigerant circuit 6 is in this state, the compressor 11 is driven, and the refrigerant discharged from the compressor 11 flows through the discharge pipe 21 and into the four-way valve 12, and then flows through the outdoor gas pipe 24 and into the gas pipe 5. The refrigerant flowing in the gas pipe 5 flows into the indoor unit 3 through the gas pipe connection 52. The refrigerant flowing into the indoor unit 3 flows through the indoor gas pipe 56 and then into the indoor heat exchanger 51. The refrigerant flowing into the indoor heat exchanger 51 exchanges heat with the indoor air that is drawn into the indoor unit 3 by the rotation of the indoor unit fan 54 and is condensed. That is, the indoor heat exchanger 51 functions as a condenser, and the indoor air heated by exchanging heat with the refrigerant in the indoor heat exchanger 51 is blown into the room through the exhaust port not shown, thereby heating the room where the indoor unit 3 is installed.

[0048] Refrigerant flowing from indoor heat exchanger 51 into indoor liquid pipe 57 flows out through liquid pipe connection 53 to liquid pipe 4. Refrigerant flowing into liquid pipe 4 flows into outdoor unit 2. Refrigerant flowing into outdoor unit 2 flows through outdoor liquid pipe 25 and is depressurized when passing through expansion valve 14. The refrigerant depressurized in expansion valve 14 flows through outdoor liquid pipe 25 and then into outdoor heat exchanger 13, where it exchanges heat with outside air flowing into outdoor unit 2 through the air intake (not shown) via the rotation of outdoor unit fan 16, thereby evaporating. Refrigerant flowing from outdoor heat exchanger 13 into outdoor refrigerant pipe 26 flows sequentially into four-way valve 12, outdoor refrigerant pipe 26, liquid receiver 15 and suction pipe 22, is then drawn into compressor 11 and compressed again, and then flows out through the first valve port 12A and the fourth valve port 12D of four-way valve 12 to outdoor gas pipe 24.

[0049] In addition, when the air conditioner 1 is in cooling operation, the four-way valve 12 is switched to connect the first valve port 12A with the second valve port 12B, and the third valve port 12C with the fourth valve port 12D. Figure 2 (The state is shown by the dashed line). Thus, the refrigerant circuit 6 is formed as a refrigeration cycle in which the indoor heat exchanger 51 functions as an evaporator and the outdoor heat exchanger 13 functions as a condenser. Furthermore, for ease of explanation, [the following is used...] Figure 2 The dashed arrows shown represent the flow of refrigerant during refrigeration operation.

[0050] When refrigerant circuit 6 is in this state, compressor 11 is driven. The refrigerant discharged from compressor 11 flows through discharge pipe 21 and into four-way valve 12, then flows through outdoor refrigerant pipe 23 and into outdoor heat exchanger 13. The refrigerant flowing into outdoor heat exchanger 13 exchanges heat with the outdoor air drawn into outdoor unit 2 by the rotation of outdoor unit fan 16 and is condensed. In other words, outdoor heat exchanger 13 functions as a condenser, and the outdoor air heated by refrigerant in outdoor heat exchanger 13 is blown to the outside through the exhaust port not shown.

[0051] Refrigerant flowing from outdoor heat exchanger 13 into outdoor liquid line 25 is depressurized by passing through expansion valve 14. The depressurized refrigerant then flows through liquid line 4 into indoor unit 3. The refrigerant flowing into indoor unit 3 flows through indoor liquid line 57 and into indoor heat exchanger 51, where it exchanges heat with indoor air flowing into indoor unit 3 through an inlet (not shown) via indoor fan 54, thus evaporating. In other words, indoor heat exchanger 51 functions as an evaporator, and the cooled indoor air, after heat exchange with the refrigerant in indoor heat exchanger 51, is blown into the room through an outlet (not shown), thereby cooling the room where indoor unit 3 is located.

[0052] The refrigerant flowing from the indoor heat exchanger 51 into the gas pipe 5 via the gas pipe connection 52 flows through the outdoor gas pipe 24 of the outdoor unit 2 and then into the fourth valve port 12D of the four-way valve 12. The refrigerant flowing into the fourth valve port 12D of the four-way valve 12 flows into the refrigerant inflow side of the receiver 15 from the third valve port 12C. The refrigerant flowing into the receiver 15 from the refrigerant inflow side is drawn into the compressor 11 via the suction pipe 22 and compressed again.

[0053] When the air conditioner 1 is in cooling or heating operation as described above, the acquisition unit 42 in the control circuit 18 acquires the sensor values ​​of the discharge temperature sensor 31, the outdoor heat exchange outlet sensor 32, and the outside air temperature sensor 33 through the control circuit 17 of the outdoor unit 2. Furthermore, the acquisition unit 42 acquires the sensor values ​​of the indoor heat exchange intermediate sensor 58 and the suction temperature sensor 59 of the indoor unit 3.

[0054] Figure 4 This is a Morrill diagram representing the refrigeration cycle of air conditioner 1. As described above, during the cooling operation of air conditioner 1, the outdoor heat exchanger 13 functions as a condenser and the indoor heat exchanger 51 functions as an evaporator. During the heating operation of air conditioner 1, the outdoor heat exchanger 13 functions as an evaporator and the indoor heat exchanger 51 functions as a condenser.

[0055] Compressor 11 draws low-temperature, low-pressure gaseous refrigerant from the evaporator. Figure 4 The refrigerant in state A at point A is compressed into a high-temperature, high-pressure gaseous refrigerant (becoming...). Figure 4 The refrigerant (in state B) is discharged after being discharged. Furthermore, the temperature of the gaseous refrigerant discharged by compressor 11 is the refrigerant discharge temperature, which is detected by discharge temperature sensor 31.

[0056] The condenser condenses the high-temperature, high-pressure gaseous refrigerant from compressor 11 after heat exchange with air. At this point, in the condenser, the gaseous refrigerant has completely transformed into liquid refrigerant through latent heat change, and the temperature of the liquid refrigerant decreases through sensible heat change, becoming a subcooled state. Figure 4 (The state of point C). Furthermore, the temperature at which the gaseous refrigerant changes into liquid refrigerant through latent heat change is the condensation temperature, and the temperature of the refrigerant in its subcooled state at the condenser outlet is the heat exchange outlet temperature. The heat exchange outlet temperature is detected by the outdoor heat exchange outlet sensor 32 during cooling operation. Furthermore, the refrigerant flow direction during heating operation is opposite to that during cooling operation, and the outdoor heat exchanger 13 functions as an evaporator. During heating operation, the outdoor heat exchange outlet sensor 32 is used to detect the temperature of the outdoor heat exchanger 13 to detect icing or control defrosting operation.

[0057] Expansion valve 14 reduces the pressure of the low-temperature, high-pressure refrigerant flowing from the condenser. The refrigerant reduced by expansion valve 14 becomes a two-phase refrigerant consisting of a gas and a liquid mixture. Figure 4 The refrigerant at point D (state of the refrigerant).

[0058] The evaporator allows the incoming gas-liquid two-phase refrigerant to exchange heat with the air, causing it to evaporate. At this point, the gas-liquid two-phase refrigerant in the evaporator has completely transformed into a gaseous refrigerant through latent heat change, and then the temperature of the gaseous refrigerant rises through sensible heat change, reaching a superheated state. Figure 4 The refrigerant (at point A) is then drawn into compressor 11. Furthermore, the temperature at which the liquid refrigerant changes to gaseous refrigerant through latent heat change is the evaporation temperature. The evaporation temperature is the indoor heat exchange intermediate temperature detected by indoor heat exchange intermediate sensor 58 during cooling operation. Additionally, the temperature of the refrigerant drawn into compressor 11 after being superheated in the evaporator is the suction temperature. Furthermore, the refrigerant flow direction during heating operation is opposite to that during cooling operation, and indoor heat exchanger 51 functions as a condenser. The detection result of indoor heat exchange intermediate sensor 58 is used to calculate the target discharge temperature.

[0059] Structure of the inference model

[0060] The extrapolation model is generated using any one of the multiple operating state variables (features) through a regression analysis method, namely, multiple regression analysis. In multiple regression analysis, the extrapolation model is generated from the regression equations obtained using actual air conditioners (hereinafter referred to as physical units) (the results of experiments demonstrating how the operating state variables would change when the refrigerant charge remaining in the refrigerant circuit changes due to the use of physical units) and multiple simulation results (the results of numerical calculations reproducing the refrigerant circuit and calculating how the operating state variables would change relative to the remaining refrigerant charge). The regression equation with the smallest P-value (a pre-defined weighting parameter representing the degree of influence of the operating state variables on the accuracy of the generated extrapolation model) and the largest possible correction value R² (representing the accuracy of the generated extrapolation model) between 0.9 and 1.0 is selected. Among them, the P-value and the correction value R2 are values ​​related to the accuracy of the inference model when generating the inference model through multiple regression analysis. The smaller the P-value, or the closer the correction value R2 is to 1.0, the higher the accuracy of the generated inference model.

[0061] The calculation models include a refrigeration calculation model 62A and a heating calculation model 62B. In this embodiment, as described below, these calculation models are generated using test results from a physical machine and are pre-stored in the control circuit 18 of the air conditioner 1.

[0062] The refrigeration estimation model 62A is a first regression equation that can accurately estimate the residual refrigerant charge during refrigeration operation using operating state variables during refrigeration operation, such as the first operating state variable or the second operating state variable.

[0063] First regression equation = (α1 × compressor speed) + (α2 × expansion valve opening) + (α3 × compressor discharge temperature) + (α4 × heat exchange outlet temperature) + (α5 × outside air temperature) + α6……(1)

[0064] The coefficients α1 to α6 are determined when generating the calculation model. At a preset time of day, the control unit 45 calculates the residual refrigerant charge in the refrigerant circuit 6 at the time point when the first or second operating state quantity is detected by the detection unit 43. This is done by substituting the compressor 11 speed, expansion valve 14 opening, compressor 11 refrigerant discharge temperature, heat exchange outlet temperature, and outside air temperature from the first or second operating state quantity detected by the detection unit 43 during the previous 24 hours into the first regression equation. Furthermore, the control unit 45 uses either the average of the residual refrigerant charge calculated using the first operating state quantity at each time point, or the average of the residual refrigerant charge calculated using the second operating state quantity at each time point, as the estimated value of the residual refrigerant charge for the previous day. The reason for substituting the compressor 11 speed, expansion valve opening, compressor 11 refrigerant discharge temperature, outdoor heat exchange outlet temperature, and outside air temperature is that the features used in generating the refrigeration calculation model 62A should be used. The compressor 11 speed is detected, for example, by a speed sensor of the compressor 11 (not shown). The opening degree of the expansion valve is determined, for example, by the number of pulses of a pulse signal input from the control unit 45 to the stepper motor (not shown) of the expansion valve. The refrigerant discharge temperature of the compressor 11 is detected by the discharge temperature sensor 31. The heat exchange outlet temperature is detected by the outdoor heat exchange outlet sensor 32. The outside air temperature is detected by the outside air temperature sensor 33.

[0065] The heating calculation model 62B is a second regression equation that can use operating state quantities during heating operation, such as first or second operating state quantities, to calculate the residual refrigerant charge during heating operation with high accuracy.

[0066] The second regression equation = (α11 × compressor speed) + (α12 × expansion valve opening) + (α13 × compressor discharge temperature) + (α14 × indoor heat exchange intermediate temperature) + α15……(2)

[0067] The coefficients α11 to α15 are determined when generating the calculation model. At a preset time of day, the control unit 45 calculates the residual refrigerant charge in the refrigerant circuit 6 at the time point when the first or second operating state quantity is detected by the detection unit 43. This is done by substituting the compressor 11 speed, expansion valve 14 opening, refrigerant discharge temperature of the compressor 11, and indoor heat exchange intermediate temperature from the first or second operating state quantity detected by the detection unit 43 during the previous 24 hours into the second regression equation. Furthermore, the control unit 45 uses either the average value of the residual refrigerant charge calculated using the first operating state quantity at each time point, or the average value of the residual refrigerant charge calculated using the second operating state quantity at each time point, as the estimated value of the residual refrigerant charge for the previous day. The reason for substituting the compressor 11 speed, expansion valve 14 opening, refrigerant discharge temperature of the compressor 11, and indoor heat exchange intermediate temperature is that the features used in generating the heating calculation model 62B should be used. The compressor 11 speed is detected by a speed sensor of the compressor 11 (not shown). The opening degree of the expansion valve is determined, for example, by the number of pulses of a pulse signal input from the control unit 45 to the stepper motor (not shown) of the expansion valve. The refrigerant discharge temperature of the compressor 11 is detected by the discharge temperature sensor 31. In the heat exchanger temperature, the indoor intermediate heat exchange temperature is detected by the indoor intermediate heat exchange sensor 58.

[0068] As mentioned above, the first regression equation is used to calculate the remaining refrigerant charge during cooling operation. Conversely, the second regression equation is used to calculate the remaining refrigerant charge during heating operation.

[0069] Methods for generating regression equations

[0070] Next, the features used in generating the first and second regression equations will be explained. During cooling operation using the first regression equation, in this embodiment, the features used to generate the first regression equation via multiple regression analysis include the compressor 11 speed, the opening degree of the expansion valve 14, the refrigerant discharge temperature of the compressor 11, the outdoor heat exchange outlet temperature, and the outdoor air temperature. Furthermore, the operating state quantities used are based on experimental results from a physical machine. Similarly, during heating operation using the second regression equation, in this embodiment, the features used to generate the second regression equation via multiple regression analysis include the compressor 11 speed, the opening degree of the expansion valve 14, the refrigerant discharge temperature of the compressor 11, and the indoor heat exchange intermediate temperature. Again, the operating state quantities used are based on experimental results from a physical machine. Furthermore, when generating the aforementioned cooling calculation model 62A (the first regression equation) or heating calculation model 62B (the second regression equation), the first operating state quantity detected when the first stability condition is met is used.

[0071] Specifically, as an example, during the design phase of air conditioner 1, a trial run of air conditioner 1 is conducted while indoor unit 3 is running, by changing the outside temperature, indoor temperature, and refrigerant charge to obtain the relationship between the characteristics and the refrigerant shortage rate. As conditions for conducting the trial run, for example, the outside temperature is varied to 20°C, 25°C, 30°C, 35°C, and 40°C. Furthermore, other parameters related to the outside temperature can also be incorporated during the trial run.

[0072] Any operating state variable (feature) used in the extrapolation model among multiple operating state variables is derived from experimental results (hereinafter referred to as training data) representing the relationship between multiple operating state variables and refrigerant charge. Specifically, the training data is data that correlates the residual refrigerant charge with each operating state variable operating at that residual refrigerant charge (training data used to generate the extrapolation model in multiple regression analysis), wherein the residual refrigerant charge varies with changes in the refrigerant charge filling the refrigerant loop.

[0073] In multivariate regression analysis, for example, a trial run is conducted with varying refrigerant charge levels to obtain different operating state quantities for each external temperature at each refrigerant charge level, and these quantities are categorized into data for each refrigerant charge level. Operating state quantities used for training data include, for example, the operating state quantities of compressor 11, indoor unit 3, and outdoor unit 2. Operating state quantities of compressor 11 include, for example, speed, target speed, running time, refrigerant discharge temperature, target discharge temperature, and output voltage. Furthermore, operating state quantities of indoor unit 3 include, for example, the speed and target speed of indoor unit fan 54, and the temperature of the intermediate sensor on the heat exchanger. Furthermore, operating state quantities of outdoor unit 2 include, for example, the speed and target speed of outdoor unit fan 16, the opening degree of expansion valve 14, and the temperature of the condenser outlet sensor. Furthermore, the data for each refrigerant charge level is used as training data for machine learning to extract arbitrary operating state quantities (features) used to calculate the remaining refrigerant charge and derive coefficients to generate a calculation model.

[0074] Acquisition and processing of running status variables

[0075] Next, the operation of obtaining the operating status quantity through the air conditioner 1 of Example 1 will be described. Figure 5 This is a flowchart illustrating an example of the processing actions of the control circuit 18 related to the acquisition of operating state quantities. Figure 5In step S11, the acquisition unit 42 of the control circuit 18 determines whether it is in a preset time for acquiring operating status data. The preset time may be, for example, a time when the operating status data is acquired on a 5-minute cycle. If the preset time is in effect (step S11: Yes), the acquisition unit 42 acquires the operating status data of the air conditioner 1 (step S12). After acquiring the operating status data of the air conditioner 1, the acquisition unit 42 stores the operating status data in the operating status data memory 61 (step S13) and returns to the processing of step S11. If the acquisition unit 42 is not in a preset time in step S11 (step S11: No), it returns to the processing of step S11.

[0076] Detection and processing actions of running status quantities

[0077] Figure 6 This is a flowchart illustrating an example of the processing actions of the control circuit 18 related to the detection of operating state quantities. Figure 6 In step S21, the detection unit 43 of the control circuit 18 refers to the operating status data stored in the operating status data memory 61 at a preset time of day (e.g., 1 AM as mentioned above) to determine whether there is an operating status data acquired 8 minutes after the compressor 11 starts (step S21). If there is an operating status data acquired 8 minutes after the compressor 11 starts (step S21: Yes), the detection unit 43 determines whether there is an operating status data acquired when the state of the compressor 11 fluctuating within a second preset range, such as ±5 rpm, lasts for a second preset period, such as 12 minutes or more, that is, when the second stable condition is met (step S22). Furthermore, the operating status data acquired and stored in the operating status data memory 61 at 5-minute intervals are marked with a timestamp indicating the time of acquisition. The detection unit 43 can determine whether there is an operating status data acquired during the period when the second stable condition is met by referring to the timestamp marked on the operating status data.

[0078] If there is no operating status quantity in the operating status quantity memory 61 when the state of the compressor 11 speed fluctuation within a second preset range lasts for a second preset period or more (step S22: No), the detection unit 43 determines whether there is an operating status quantity in the operating status quantity memory 61 when the state of the compressor 11 speed fluctuation within a first preset range, for example ±1 rpm, lasts for a first preset period, for example 5 minutes or more (step S23). If there is an operating status quantity in the operating status quantity memory 61 when the state of the compressor 11 speed fluctuation within a first preset range lasts for a first preset period or more (step S23: Yes), the detection unit 43 determines whether there is an operating status quantity among the operating status quantities that meet the conditions of step S23 when the absolute value of the difference between the refrigerant discharge temperature and the target discharge temperature of the compressor 11 is a preset value, for example 2°C or less, lasts for a first preset period or more (step S24). In other words, the detection unit 43 determines whether the running state quantity memory 61 contains a running state quantity acquired when the first stable condition is met by performing the judgments in steps S23 and S24. Furthermore, the detection unit 43 determines whether a running state quantity acquired during the period when the first stable condition is met is present by referring to the timestamp marked in the running state quantity.

[0079] If, among the operating state quantities that satisfy the conditions of step S23, there exists an operating state quantity that has been acquired for a first preset period or longer when the absolute value of the difference between the refrigerant discharge temperature of compressor 11 and the target discharge temperature is below a preset value (step S24: Yes), then the detection unit 43 detects the matching operating state quantity as the first operating state quantity (step S25). Further, the detection unit 43 stores the first operating state quantity detected in step S25 in the first operating state quantity memory 61A (step S26) and returns to the processing of step S21.

[0080] Furthermore, if the detection unit 43 has an operating state quantity stored in the operating state quantity memory 61 that has been acquired for a second preset period or longer when the state of fluctuation of the compressor 11 speed within a second preset range is present (step S22: Yes), the corresponding operating state quantity is detected as a second operating state quantity (step S27). The detection unit 43 stores the second operating state quantity detected in step S27 in the second operating state quantity memory 61B (step S28) and proceeds to the processing in step S23.

[0081] Furthermore, if the detection unit 43 does not have an operating status quantity acquired 8 minutes after the compressor 11 starts in the operating status quantity memory 61 (step S21: No), it returns to the process of step S21. Furthermore, if the detection unit 43 does not have an operating status quantity acquired in the operating status quantity memory 61 when the compressor 11 speed fluctuation is within a first preset range for a first preset period or more (step S23: No), it returns to the process of step S21. Furthermore, if, among the operating status quantities satisfying the conditions of step S23, the detection unit 43 does not have an operating status quantity acquired when the absolute value of the difference between the refrigerant discharge temperature and the target discharge temperature of the compressor 11 is below a preset value for a first preset period or more (step S24: No), it returns to the process of step S21.

[0082] The process of calculating and processing residual refrigerant

[0083] Figure 7 This is a flowchart illustrating an example of the processing actions of control circuit 18 related to the calculation of residual refrigerant. Figure 7 In this process, the control unit 45 of the control circuit 18 determines whether a calculation opportunity has been reached (step S31). Furthermore, the calculation opportunity is a preset time within a day, such as 1:00 AM. If a calculation opportunity has been reached (step S31: Yes), the control unit 45 counts the number of first operating state quantities (detection count) acquired within a preset period, such as the entire day of the previous day (step S32), and determines whether the number of first operating state quantities detected within the preset period is greater than or equal to a preset number, such as 50 or more (step S33).

[0084] If the number of first operating state quantities detected within a preset period is greater than a preset number (step S33: Yes), the control unit 45 uses the first operating state quantities and each calculation model to calculate the residual refrigerant charge of the refrigerant circuit 6 for each acquired first operating state quantity (step S34). For example, during cooling operation, the control unit 45 uses the first operating state quantities and the cooling calculation model 62A to calculate the residual refrigerant charge of the refrigerant circuit 6 for each acquired first operating state quantity. Furthermore, during heating operation, the control unit 45 uses the first operating state quantities and the heating calculation model 62B to calculate the residual refrigerant charge of the refrigerant circuit 6 for each acquired first operating state quantity.

[0085] If the number of first operating state quantities detected by the control unit 45 within a preset period is less than a preset number (step S33: No), that is, if the number of detections is less than the preset number, the control unit 45 uses the second operating state quantities and a calculation model to calculate the remaining refrigerant charge of the refrigerant circuit 6 for each of the acquired second operating state quantities (step S35). For example, during cooling operation, the control unit 45 uses the second operating state quantities and a cooling calculation model 62A to calculate the remaining refrigerant charge of the refrigerant circuit 6 for each of the acquired second operating state quantities. Furthermore, during heating operation, the control unit 45 uses the second operating state quantities and a heating calculation model 62B to calculate the remaining refrigerant charge of the refrigerant circuit 6 for each of the acquired second operating state quantities.

[0086] Next, the control unit 45 calculates the average value of each remaining refrigerant charge calculated in step S34 or in step S35 (step S36), and determines whether the average value of each remaining refrigerant charge is less than a preset value (step S37). The preset value refers to a value that has been determined in previous tests, etc., that if the refrigerant charge filled in the refrigerant circuit 6 is less than this preset value, it will cause problems with the air conditioning capacity of the air conditioner 1. For example, it is a refrigerant charge that is 60% of the refrigerant charge filled in the refrigerant circuit 6 when the air conditioner 1 is set up.

[0087] If the average value of the calculated residual cooling capacity is less than the preset value (step S37: Yes), the control unit 45 outputs the calculated average value as the estimated value of the residual cooling capacity (step S38) and returns to the processing in step S31. The output of the estimated value of the residual cooling capacity, for example, means sending the estimated value of the residual cooling capacity to a remote control (not shown) or a mobile terminal of a user operating the indoor unit 3 or the air conditioner 1. Upon receiving the estimated value of the residual cooling capacity, the remote control or mobile terminal displays the received estimated value of the residual cooling capacity on each display unit.

[0088] Furthermore, if the control unit 45 is not in the calculation phase in step S31 (step S31: No), it returns to the processing of step S31. Additionally, if the average value of each remaining refrigerant charge calculated by the control unit 45 in step S37 is less than the preset value (step S37: No), it returns to the processing of step S31.

[0089] Effects of Example 1

[0090] In Example 1, the air conditioner 1 uses a first operating state quantity representing the operating state of the air conditioner when the refrigerant circuit 6 meets the first stable condition, and various calculation models for cooling / heating operation, to calculate the residual refrigerant charge remaining in the refrigerant circuit 6. Since the first operating state quantity is also used in the generation of each calculation model, the residual refrigerant charge can be accurately calculated as long as the first operating state quantity is used in the calculation of the residual refrigerant charge. Furthermore, when the first stable condition is not met, that is, when it is difficult to achieve a stable state for the refrigerant circuit 6, the residual refrigerant charge remaining in the refrigerant circuit 6 is calculated using a second operating state quantity representing the operating state of the air conditioner when the refrigerant circuit 6 meets the second stable condition, and various calculation models for cooling / heating operation. If the second operating state quantity is applied to the calculation of the residual cooling dose, the accuracy of each calculation will decrease compared to the case where the first operating state quantity is used. However, since more second operating state quantities are available than first operating state quantities, the accuracy of the residual cooling dose calculation can be ensured by averaging each calculation result and using the average value as the calculated value of the residual cooling dose.

[0091] If the number of detections of the first operating state quantity within a preset period is greater than or equal to a preset number, the control unit 45 uses the first operating state quantity and a calculation model to calculate the remaining refrigerant charge. If the number of detections of the first operating state quantity within the preset period is less than the preset number, the control unit 45 uses the second operating state quantity and a calculation model to calculate the remaining refrigerant charge. As a result, the first operating state quantity and the second operating state quantity can be used separately when calculating the remaining refrigerant charge.

[0092] When the remaining refrigerant is calculated using the second operating state quantity and the calculation model at each preset time, the control unit 45 outputs the average value of the remaining refrigerant calculated at each preset time within a preset period as the remaining refrigerant for the preset period. As a result, the remaining refrigerant can be calculated with high accuracy.

[0093] Furthermore, in Embodiment 1, the state satisfying the first stability condition is defined as follows: the state in which the rotational speed of the compressor 11 fluctuates within a first preset range for a first preset period or more, and the state in which the absolute value of the difference between the refrigerant discharge temperature of the compressor 11 and the target discharge temperature is below a preset value for a first preset period or more. However, it is also possible to define the state satisfying the first stability condition simply as the state in which the rotational speed of the compressor 11 fluctuates within a first preset range for a first preset period or more, and this can be appropriately modified.

[0094] In Example 1, a state in which the rotational speed of compressor 11 fluctuates within a second preset range for a second preset period or more is considered a state that satisfies the second stability condition, wherein the second preset range exceeds the first preset range, and the second preset period exceeds the first preset period. However, even if the fluctuation does not last for a second preset period or more, a state in which the rotational speed of compressor 11 fluctuates within a second preset range for a first preset period or more can be considered a state that satisfies the second stability condition, and can be appropriately modified.

[0095] In Example 1, an example is shown where the remaining cooling dose is calculated at each preset time, but the calculation may not be performed periodically and can be changed as appropriate.

[0096] Example 1 illustrates the following scenario: during the design phase of the air conditioner 1, various operating state variables are obtained through trial operation of the air conditioner 1. A calculation model is obtained by having a terminal such as a server with learning capabilities learn the test results, and the control circuit 18 pre-stores this calculation model. Alternatively, various operating state variables can be obtained through simulation, and a calculation model can be obtained by learning the obtained results, and this calculation model can be pre-stored. Furthermore, a server 120 connected to the air conditioner 1 via a communication network 110 can exist. This server 120 generates a first regression equation and a second regression equation and sends them to the air conditioner 1. This implementation method will be described below.

[0097] Example 2

[0098] Structure of air conditioning system

[0099] Figure 8 This is an explanatory diagram illustrating an example of the air conditioning system 100 of Embodiment 2. Furthermore, the same symbols are used to denote structures identical to those in the air conditioner 1 of Embodiment 1, thus omitting descriptions of repetitive structures and operations. Figure 8 The air conditioning system 100 shown includes: an air conditioner 1 as described in Embodiment 1, a communication network 110, and a server 120. The air conditioner 1 is communicatively connected to the server 120 via the communication network 110.

[0100] Server 120 has a generation unit 121 and a transmission unit 122. The generation unit 121 generates a calculation model using multiple regression analysis, based on operating state quantities related to the calculation of the residual refrigerant charge in the refrigerant circuit 6. The calculation model includes, for example, the refrigeration calculation model 62A and the heating calculation model 62B described in Embodiment 1. The transmission unit 122 transmits each calculation model generated by the generation unit 121 to the air conditioner 1 via the communication network 110. The control circuit 18 within the air conditioner 1 uses the received calculation models to calculate the residual refrigerant charge in the refrigerant circuit 6 of the air conditioner 1.

[0101] The generation unit 121 within the server 120 periodically collects operating status data during refrigeration operation from a standard unit of the air conditioner 1 (located in the manufacturer's laboratory, etc.) capable of actually measuring the residual refrigerant charge in the refrigerant circuit 6. Using the comparison results between the residual refrigerant charge calculated by each calculation model and the actually measured residual refrigerant charge, along with the collected operating status data, it generates or updates the refrigeration calculation model 62A. Furthermore, the transmission unit 122 within the server 120 periodically sends the generated or updated refrigeration calculation model 62A to the air conditioner 1. Alternatively, as in Embodiment 1, the operating status data used to generate each calculation model can be obtained through simulation, and the generation unit 121 uses the operating status data obtained through simulation to generate each calculation model.

[0102] The generation unit 121 within the server 120 periodically collects operating status data during heating operation from the standard unit of the air conditioner 1 described above. Using a comparison between the residual refrigerant charge calculated by the calculation model and the actual measured residual refrigerant charge, along with the collected operating status data, it generates a heating calculation model 62B. Furthermore, the transmission unit 122 within the server 120 periodically sends the generated heating calculation model 62B to the air conditioner 1. Alternatively, as in Embodiment 1, the operating status data used to generate each calculation model can be obtained through simulation, and the generation unit 121 uses the simulated operating status data to generate each calculation model.

[0103] Effects of Example 2

[0104] In Example 2, server 120 uses operating status variables related to the estimation of residual refrigerant charge in refrigerant circuit 6, employs multiple regression analysis to generate a estimation model for estimating the residual refrigerant charge, and sends the generated estimation model to air conditioner 1. Air conditioner 1 uses the estimation model received from server 120 and the current operating status variables to estimate the residual refrigerant charge. As a result, even a household air conditioner 1 can use a highly accurate estimation model to estimate the current residual refrigerant charge.

[0105] Furthermore, this embodiment describes the calculation of the residual refrigerant amount remaining in the refrigerant circuit 6. However, the present invention is not limited to this. Specifically, the refrigerant shortage rate can also be calculated, which is the proportion of the amount of refrigerant leaking from the refrigerant circuit 6 to the outside relative to the initial amount of refrigerant filled into the refrigerant circuit 6. Furthermore, the calculated refrigerant shortage rate can be multiplied by the initial value to provide the amount of refrigerant leaking from the refrigerant circuit 6 to the outside. Additionally, a calculation model can be generated to calculate the absolute amount of refrigerant leaking from the refrigerant circuit 6 to the outside or the absolute amount of refrigerant remaining in the refrigerant circuit 6, and the calculation results based on this model can be provided. When generating the calculation model to calculate the absolute amount of refrigerant leaking from the refrigerant circuit 6 to the outside or the absolute amount of refrigerant remaining in the refrigerant circuit 6, in addition to the various operating state quantities described so far, the volumes of the outdoor heat exchanger 13 and the indoor heat exchanger 51, as well as the volume of the liquid pipe 4, need only be considered.

[0106] Furthermore, the refrigerant shortage rate is the proportion of the amount of refrigerant less than the specified amount when the refrigerant is filled to 100%. Alternatively, the refrigerant shortage rate can be calculated immediately after the specified amount of refrigerant has been filled into the refrigerant circuit 6, and this calculated result can be taken as 100%. For example, if the calculated refrigerant shortage rate is 90% after the specified amount of refrigerant has been filled into the refrigerant circuit 6, that is, if the amount of refrigerant filled into the refrigerant circuit 6 is calculated to be 10% less than the specified amount, this 10% less refrigerant amount can also be taken as 100%. By combining this 100% refrigerant amount with the calculated result, the subsequent refrigerant shortage rate can be calculated more accurately.

[0107] Variations

[0108] This embodiment illustrates the case where the control circuit 18 of the indoor unit 3 controls the entire air conditioner 1, but the control circuit 18 can also be located on the outdoor unit 2 or the cloud side. This embodiment illustrates the case where the calculation model is generated by the server 120, but it is also possible to calculate the calculation model manually based on simulation results without using the server 120. Furthermore, this embodiment illustrates the case where the control circuit 18 of the indoor unit 3 uses the calculation model to calculate the refrigerant dosage, but the refrigerant dosage can also be calculated by the server 120 that generates the calculation model. Additionally, this embodiment illustrates the case where various calculation models are generated using multiple regression analysis, but machine learning algorithms capable of performing ordinary regression analysis, such as SVR (Support Vector Regression) or NN (Neural Network), can also be used to generate the calculation model. In this case, for feature selection, instead of the P-value and correction value R used in multiple regression analysis, ordinary methods for selecting features in a way that improves the accuracy of the calculation model (such as forward feature selection or backward feature elimination) can be used.

[0109] Furthermore, each structural element of the various parts shown in the attached figures does not necessarily need to be physically constructed as shown in the figures. That is, the specific form of the distribution / combination of the various parts is not limited to that shown in the attached figures, and can be functionally or physically distributed or combined in any unit according to various loads or usage conditions.

[0110] Furthermore, the various processing functions performed by each device can also be executed, in whole or in part, on a microcomputer such as a CPU (Central Processing Unit) (or MPU (Micro Processing Unit), MCU (Micro Controller Unit), etc.). In addition, it is obvious that the various processing functions can also be executed, in whole or in part, on a program analyzed and executed by the CPU (or MPU, MCU, etc.), or on hardware using wiring logic.

[0111] Symbol Explanation

[0112] 1. Air conditioner

[0113] 2 Outdoor unit

[0114] 3 Indoor unit

[0115] 11 Compressor

[0116] 18 Control Circuit

[0117] 42 Acquisition Department

[0118] 43. Testing Department

[0119] 44 Storage Department

[0120] 45 Control Department

[0121] 61A First Operating State Memory

[0122] 61B Second Operating State Memory

[0123] 62A Refrigeration Calculation Model

[0124] 62B Heating Calculation Model

Claims

1. An air conditioner comprising a refrigerant circuit connecting an indoor unit to an outdoor unit via refrigerant piping, the outdoor unit comprising a compressor, an outdoor heat exchanger, and an expansion valve, the indoor unit comprising an indoor heat exchanger, the refrigerant circuit being filled with a preset amount of refrigerant, the air conditioner being characterized in that it has: The acquisition department periodically acquires the operating status data of the air conditioner during operation; A storage unit, which stores the operating state quantities acquired by the acquisition unit; The calculation model uses the operating state variables to calculate the residual amount of refrigerant remaining in the refrigerant circuit; The detection unit is used to detect a first operating state quantity or a second operating state quantity from the storage unit. The first operating state quantity is the operating state quantity when the refrigerant circuit meets a first stability condition, and the second operating state quantity is the operating state quantity when the refrigerant circuit meets a second stability condition that is different from the first stability condition. as well as Control Department If the number of the first operating state quantity detected by the detection unit within a preset period is greater than or equal to a preset number, the control unit uses the calculation model and the first operating state quantity to calculate the residual refrigerant charge in the refrigerant circuit. If the number of first operating state quantities detected by the detection unit within the preset period is less than the preset number, the control unit uses the second operating state quantity and the calculation model to calculate the remaining cooling dose.

2. The air conditioner according to claim 1, characterized in that, The second stability condition is a condition that is relaxed compared to the first stability condition.

3. The air conditioner according to claim 1 or 2, characterized in that, The detection unit will use the operating state quantity detected when the first stability condition is met as the first operating state quantity. The first stability condition is that the fluctuation of the compressor speed within a first preset range continues for more than a first preset period. The operating state quantity detected when the second stability condition is met is taken as the second operating state quantity. The second stability condition is that the fluctuation of the compressor speed within a second preset range continues for more than the first preset period or continues for more than the second preset period beyond the first preset period, wherein the second preset range exceeds the first preset range.

4. The air conditioner according to claim 3, characterized in that, The state in which the absolute value of the difference between the refrigerant discharge temperature and the target discharge temperature of the compressor is below a preset value for a period of time or more is added to the first stabilization condition. The detection unit will use the operating state quantity detected when the first stabilization condition is met as the first operating state quantity.

5. The air conditioner according to claim 1 or 2, characterized in that, The detection unit detects the first operating state quantity, and Detect the second operating state quantity.

6. The air conditioner according to claim 1 or 2, characterized in that, When the residual cooling dose is calculated using the second operating state quantity and the calculation model at each preset time, the control unit outputs the average value of the residual cooling dose calculated at each preset time within a preset period as the residual cooling dose within the preset period.

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