JP2011196599A - Air conditioner and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner and a method of controlling the air conditioner capable of improving energy consumption efficiency.SOLUTION: This air conditioner including a refrigerant circuit which is constituted by successively connecting a compressor 4, a condenser 2, a refrigerant flow rate regulating means 8 and an evaporator 6 by piping and in which a refrigerant is circulated, further includes a gas-liquid two-phase region calculating means for determining dryness at an outlet of the evaporator 6, and a ratio of gas-liquid two-phase regions inside of the evaporator 6 on the basis of an operating state of the refrigerant circuit, and a control means for controlling the ratio of the gas-liquid two-phase regions while keeping the dryness at the outlet of the evaporator 6 to a prescribed value or more by controlling at least one of an air distribution amount to the compressor 4, the refrigerant flow rate regulating means 8 and the condenser 2, and an air distribution amount to the evaporator 6.

Description

  The present invention relates to an air conditioner and an air conditioner control method.

  Conventionally, as a method for controlling the refrigeration cycle of an air conditioner, there is a method of controlling the wet state or the degree of superheat of the outlet portion within a certain range by measuring the temperature of the outlet portion of the heat exchanger (for example, a patent) Reference 1).

  Moreover, there exists what installs a flow rate sensor and a pressure sensor, and measures the wetness of the exit part of a heat exchanger directly (for example, refer patent document 2).

Japanese Patent Publication No. 61-1663 (Claim 1) JP 2002-276902 A (summary)

However, in the technique described in Patent Document 1, when the heat load greatly fluctuates, or when the heat load at the time of startup or the like is very large, the flow rate of refrigerant in the pipe fluctuates greatly, so the heat dissipation coefficient changes, An accurate wetness cannot be obtained. In addition, the heat load greatly fluctuates due to seasonal fluctuations, weather conditions, changes in user operations, changes in equipment conditions, and the like.
In addition, the method of controlling the degree of superheat by detecting the temperature and pressure only at the outlet of the evaporator only regulates the state of the outlet only, until the internal state of the evaporator is Cannot be considered.
As described above, since the heat load related to air conditioning is constantly fluctuating, in a general air conditioner, the degree of superheat is controlled with a margin of about 2 to 10 ° C as a certain degree of likelihood. Is not preferable from the viewpoint of effective use of the heat exchange area of the heat exchanger, and there is a problem that the energy consumption efficiency of the air conditioner is lowered.
Moreover, since the fluctuation | variation of a heat load is influenced greatly by the installation place and the user's operation form, it is impossible to set these likelihoods in advance.

  Further, the technique described in Patent Document 2 requires an additional sensor, and installing such a sensor in the pipe causes an increase in pressure loss, which is preferable from the viewpoint of energy efficiency and cost. There was a problem of not.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain an air conditioner and an air conditioner control method capable of improving energy consumption efficiency.

  The air conditioner according to the present invention is an air conditioner including a refrigerant circuit that circulates a refrigerant by sequentially connecting a compressor, a condenser, a refrigerant flow rate adjusting unit, and an evaporator with piping, and based on an operating state of the refrigerant circuit. Gas-liquid two-phase region calculation means for obtaining the degree of dryness of the evaporator outlet and the ratio of the gas-liquid two-phase region inside the evaporator, the compressor, the refrigerant flow rate adjusting means, the amount of air blown to the condenser, And a control means for controlling the ratio of the gas-liquid two-phase region while controlling at least one of the amount of air blown to the evaporator so that the degree of dryness of the evaporator outlet is not less than a predetermined value. .

  This invention obtains the degree of dryness of the evaporator outlet and the ratio of the gas-liquid two-phase area inside the evaporator, and controls the ratio of the gas-liquid two-phase area while setting the degree of dryness of the evaporator outlet to a predetermined value or more. For this reason, without providing an additional sensor for detecting the refrigerant state inside the evaporator, it is possible to control the ratio of the gas-liquid two-phase region while increasing the dryness of the evaporator outlet to a predetermined value or more, and the energy consumption efficiency Can be improved.

It is a refrigerant circuit figure of the air conditioner in Embodiment 1 of this invention. It is a conceptual diagram explaining the state where the evaporator 6 is excessively dry. It is a conceptual diagram explaining the state where the evaporator 6 is excessively wet. It is a conceptual diagram explaining the state in which the evaporator 6 is suitably wet. It is a flowchart which shows the control action in Embodiment 1 of this invention. It is a flowchart which shows the calculation operation in Embodiment 2 of this invention. It is a flowchart which shows the identification method of the physical parameter in Embodiment 3 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below. 1 is a refrigerant circuit diagram of an air conditioner according to Embodiment 1 of the present invention. In FIG. 1, 1 is an outdoor unit blower, 2 is a condenser, 3 is an opening / closing means such as a check valve, 4 is a compressor, 5 is a refrigerant storage means such as an accumulator, 6 is an evaporator, 7 is an indoor unit blower, 8 is a refrigerant flow rate adjusting means, for example, an electronic expansion valve, 9-1, 9-2, 9-3, 9-4, 9-5 are temperature detecting means, 10-1, 10-2, 10-3 are pressure detecting means. Means, 11 is a controller, 12 is a signal line, 14 is a liquid pipe, and 15 is a gas pipe. 16 shows the configuration of the indoor unit, and 17 shows the configuration of the outdoor unit. Particularly during cooling, among the temperature detection means 9, 9-1 and 9-2 are refrigerant gas phase temperatures, 9-3 is refrigerant liquid phase temperature, 9-5 is the indoor temperature or the suction temperature of the indoor unit 16, 9 -4 measures the outside air temperature or the ambient temperature of the condenser 2.

  The control controller 11 is provided with a data storage device and a gas-liquid two-phase region calculation means. The gas-liquid two-phase region calculation means obtains the degree of dryness at the outlet of the evaporator 6 and the ratio of the gas-liquid two-phase region in the evaporator 6 based on the operating state of the refrigerant circuit. Details will be described later. The data storage device stores information on physical model equations that simulate physical states of the compressor 4, the refrigerant flow rate adjusting means 8, the condenser 2, and the evaporator 6. In addition, information on the actual value of the operation data of the refrigerant circuit is stored. The operation data includes, for example, information on the refrigerant temperature and pressure on the inlet side and outlet side of the compressor 4, the refrigerant flow rate adjusting means 8, the condenser 2, and the evaporator 6, the rotation speed of the compressor 4, and the refrigerant flow rate. Information on the opening degree of the adjusting means 8, the air flow rate for the condenser 2, and the air flow rate for the evaporator 6. The control controller 11 may be mounted on the control panel of the air conditioner, or may be mounted on the remote controller of the indoor unit 16.

  The controller 11 corresponds to “control means” in the present invention, and the data storage device corresponds to “data storage means” and “storage means” in the present invention.

  Temperature detection means 9-1, 9-2, 9-3, 9-4, 9-5, pressure detection means 10-1, 10-2, 10-3, compressor 4, outdoor unit blower 1, indoor unit blower 7. The refrigerant flow rate adjusting means 8 is connected to the controller 11 via signal lines 12 respectively, and sequentially stores operation data such as measured values and control values in the data storage device. Further, the compressor 4, the outdoor unit blower 1, the indoor unit blower 7, and the refrigerant flow rate adjusting means 8, which are control target devices, are always controlled by a control signal from the controller 11. In the figure, one indoor unit 16 corresponds to one outdoor unit 17, but the function of acquiring, storing, and controlling measured values in the same manner in a configuration corresponding to a plurality of indoor units 16 is also provided. The same. Each apparatus is connected by the liquid piping 14 or the gas piping 15, and a refrigerant | coolant circulates through this air conditioner. Although this figure mainly shows a refrigerant circuit configuration during cooling, it can also be used as a heating cycle by changing the refrigerant flow direction using a refrigerant switching device such as a four-way valve.

  FIG. 2 is a conceptual diagram illustrating a state where the evaporator 6 is excessively dry. FIG. 2 shows an operation state in which the refrigerant in the evaporator 6 is excessively vaporized. In the liquid refrigerant region 19 from the entrance of the evaporator 6 to the point 20 where vaporization starts (interface between the liquid phase and the gas-liquid two phase), the dryness is 0, that is, the refrigerant flowing in as a liquid passes through the evaporator 6. During this time, heat is exchanged between the wall surface and the refrigerant. At this time, vaporization starts from the portion 20 where the dryness becomes 0 or more, and the region 22 from the location 21 where the dryness becomes 1 (the interface between the gas-liquid two-phase and the gas phase) is in a gas-liquid two-phase state. . This figure shows that the heat is excessively exchanged because the refrigerant temperature is higher or the flow velocity is lower than the heat exchange capacity of the evaporator 6, and the refrigerant is completely vaporized in the middle of the piping. ing. It is known that the heat exchange capacity varies greatly depending on the phase state between the wall surface and the refrigerant. Especially, when the liquid phase of the refrigerant is on the wall surface and when there is no liquid phase, the heat with the liquid phase is much larger. Exchange is possible. Therefore, maximizing the region in which the gas film and the liquid phase are generated on the wall surface, that is, the region 22 is effective in improving the heat exchange efficiency. Further, as shown in this figure, when the vaporization is completely performed on the outlet side of the evaporator 6, the gas flow rate of the refrigerant becomes very large, and therefore the pressure loss in the gas pipe 15 connected to the outlet of the evaporator 6 increases. There's a problem.

  On the other hand, FIG. 3 is a conceptual diagram illustrating a state where the evaporator 6 is excessively wet. A liquid with a dryness of 0 flows from the entrance of the evaporator 6. In this figure, the liquid refrigerant region 19 occupies most of the evaporator 6 because the refrigerant temperature is lower or the flow velocity is faster than the heat exchange capability of the evaporator 6. At this time, since the contact area between the liquid surface and the tube wall is large, the heat exchange efficiency is very high. However, since most of the inside of the evaporator 6 is covered with the liquid region, there is a problem that the pressure loss in the evaporator 6 is very high. In addition, the gas-liquid two-phase refrigerant sent from the evaporator 6 returns to the refrigerant storage device through the gas pipe 15, but at this time, if the amount of refrigerant is large, the liquid refrigerant can be mixed into the compressor 4. There is sex. When the refrigerant in the liquid state is mixed into the compressor 4, liquid compression occurs during the compression stroke, which may lead to a serious failure such as breakage of the compressor 4 due to the water hammer effect. In addition, noise due to water hammer is also a problem.

  FIG. 4 is a conceptual diagram illustrating a state where the evaporator 6 is suitably wet. In this state, the refrigerant is completely vaporized at the outlet of the evaporator 6 to prevent liquid mixture into the compressor 4. Furthermore, as the combination of the liquid region and the gas-liquid two-phase region, the combination that maximizes the energy consumption efficiency is selected in consideration of the improvement in heat exchange capacity due to the increase in the gas-liquid region and the increase or decrease in pressure loss. . At this time, the energy consumption efficiency is the amount of work performed by the air conditioner system for the input energy.

  FIG. 5 is a flowchart showing the control operation in the first embodiment of the present invention. In a normal air conditioner, since the degree of superheat or dryness at the outlet of the evaporator 6 is detected and controlled, details of the refrigerant state inside the evaporator 6 are not taken into consideration, and FIG. As shown, the evaporator 6 may not be used effectively. At this time, in order to effectively use the evaporator 6, the refrigerant needs to be in contact with the inner wall of the evaporator 6 in a liquid phase state. FIG. 5 shows a state that is suitably controlled so that the gas-liquid two-phase region where the liquid phase exists on the inner wall is maximized.

  In the following, description will be given in order. In step ST1, the controller 11 performs a normal air conditioning control sequence. This means the normal control content of the air conditioner. The normal control content is, for example, a temperature difference from the current indoor temperature to be controlled or the indoor unit suction temperature (9-5), and the outdoor temperature (9 -4), etc., to calculate the thermal load and determine the rotational speed of the compressor 4, the rotational speed of the outdoor unit blower 1, the rotational speed of the indoor unit blower 7, the flow rate of the refrigerant, etc. so as to match the thermal load And so on. There are various methods for these control methods, and any control method can be applied. That is, the control system in the present embodiment assumes a form that can be added to these normal air conditioning control systems.

  In step ST2, the controller 11 determines whether the thermal load is stable. This is because special control such as oil return is performed in the air conditioner at the time of startup or when the load fluctuates greatly. Under such control conditions, the subsequent optimum control is skipped. The condition under which the thermal load is stable varies depending on the device configuration. For example, it can be determined that the thermal load is stable when the suction temperature (9-5) does not vary for a certain period of time. .

  In step ST3, the gas-liquid two-phase region calculation means of the controller 11 calculates the outlet dryness of the evaporator 6. A method of calculating the outlet dryness of the evaporator 6 will be described in the second embodiment.

  In step ST4, the controller 11 uses the dryness on the outlet side of the evaporator 6 calculated in ST2 to ensure that no liquid refrigerant is generated on the outlet side. If it is less than the reference value, vaporization is not completed on the outlet side of the evaporator 6, and there is a risk of liquid mixing into the compressor 4, so an operation of increasing the dryness is performed in ST5. As the reference value, a dryness of about 0.95 to 1 is usually selected. As a method for reducing the degree of dryness, for example, there are methods such as reducing the flow rate of the refrigerant and reducing the amount of air blown to the evaporator 6, that is, the amount of air blown from the indoor unit blower 7.

  If the dryness is equal to or higher than the reference value in ST4, the process proceeds to the next control step on the assumption that there is no risk of liquid mixing into the compressor 4.

  In ST6, the controller 11 reads the constraint conditions used for the device control combination from a data storage device or the like. The constraint conditions at this time are, for example, the maximum and minimum operating frequencies of the compressor 4, the maximum change rate, maximum value, or minimum value of the valve opening degree of the refrigerant flow rate adjusting means 8, or the outdoor unit blower 1 Or the maximum rate of change, minimum value or maximum value of the rotational speed of the indoor unit blower 7, or the range of the temperature, pressure, enthalpy, etc. of the refrigerant being used, or a constraint formula for minimizing energy consumption And evaluation functions.

  In ST7, the controller 11 searches for a combination that satisfies the constraint condition from among the device control combinations whose dryness is equal to or higher than the reference value. For example, if “maximization of energy consumption efficiency” is selected as the constraint condition, the gas-liquid two-phase region and liquid that maximizes the energy consumption efficiency are selected from the device control value combinations whose dryness exceeds the reference value. The combination of the phase region and the complete gas region will be searched. That is, the combination of the control values that maximize the ratio of the gas-liquid two-phase region in the evaporator 6 is searched for among the combinations of the control values in which the dryness at the outlet of the evaporator 6 is equal to or higher than the reference value. The device control combination mentioned here is, for example, the rotational speed control target value of the compressor 4, the rotational speed control target value of the outdoor unit blower 1, the rotational speed control target value of the indoor unit blower 7, and the valve of the refrigerant flow rate adjusting means 8. A combination of control values such as opening control target values.

  There are various ways to search for a solution, but it must be selected appropriately considering whether the control value of the device is a continuous value or a discrete value, whether the control model of the device is linear or non-linear. Don't be. For example, if the control value can be expressed as a continuous value and the control model can be linearized, an optimization method such as linear programming or quadratic programming can be applied, and the control value is controlled by a discrete value. If the model is non-linear, optimization methods such as branch and bound and integer programming can be applied.

  In ST8, the controller 11 determines each device obtained in ST7, for example, the rotation speed of the compressor 4, the rotation speed of the outdoor unit blower 1, the rotation speed of the indoor unit blower 7, and the valve of the refrigerant flow rate adjusting means 8. The optimum value of the control value such as the opening is transmitted to each device. Note that the control unit time of one cycle must be appropriately determined in consideration of the time required for solution search and the time constant of the system. In the case where the fluctuation of the thermal load is small, this time unit may be about 1 to several minutes.

  As described above, in the present embodiment, the outlet of the evaporator 6 is dried by controlling at least one of the amount of air blown to the compressor 4, the refrigerant flow rate adjusting means 8, the condenser 2, and the amount of air blown to the evaporator 6. The ratio of the gas-liquid two-phase region is controlled while making the degree equal to or higher than the reference value. For this reason, the ratio of the gas-liquid two-phase region can be controlled while ensuring the dryness of the outlet of the evaporator 6 to a reference value or more without providing an additional sensor for detecting the refrigerant state inside the evaporator 6. , Energy consumption efficiency can be improved.

  In addition, among combinations of control values in which the degree of dryness at the outlet of the evaporator 6 is equal to or higher than a reference value, a combination of control values that maximizes the ratio of the gas-liquid two-phase region in the evaporator 6 is searched for each device. Control. For this reason, it becomes possible to improve the energy consumption efficiency of an air conditioner by performing the control which improves the heat exchange capability of the evaporator 6 under restrictions.

Embodiment 2. FIG.
In the second embodiment, a calculation operation for obtaining the dryness of the outlet of the evaporator 6 and the ratio of the gas-liquid two-phase area in the evaporator 6 by the gas-liquid two-phase area calculation means of the controller 11 will be described.

FIG. 6 is a flowchart showing the calculation operation in the second embodiment of the present invention.
In step ST9, information on the physical model for calculation is read from the data storage device of the controller 11 or the like. The information of the physical model is a state equation describing the state of the device, a transfer function that defines input / output state transitions, and the like. For example, from the valve opening degree of the refrigerant flow rate adjusting unit 8 and the temperature detecting unit 9-2. Passed through the refrigerant flow rate adjusting means 8 based on the refrigerant temperature before passing obtained, the temperature of the refrigerant after passing obtained from the temperature detecting means 9-3, and the pressure obtained from the pressure detecting means 10-2, 10-3. An expression that calculates the flow rate of refrigerant.

  In step ST10, various sensor data are acquired from the data storage device of the controller 11. The sensor data is, for example, the temperature measured from the temperature detection means 9-1, 9-2, 9-3, 9-4, 9-5 shown in FIG. 1, the pressure detection means 10-1, 10-2, The pressure measured by 10-3 is indicated. In the data storage device of the controller 11, measured values are appropriately stored as data from the above-described sensors installed in the air conditioner system.

  In step ST11, the current value of the control value of the control target device is acquired from the data storage device of the control controller 11. The control target devices are, for example, the compressor 4, the refrigerant flow rate adjusting means 8, the outdoor unit blower 1, the indoor unit blower 7, and the like. As control values of these devices, for example, if the compressor 4 is a rotary compressor, its frequency, and if the refrigerant flow rate adjusting means 8 is an electronic expansion valve, the opening of the valve, the outdoor unit blower 1, the indoor unit blower If it is 7, it is the number of revolutions. There are various data formats such as current values, pulse counts per unit time, applied voltage, etc., but these are uniquely related to the number of rotations and valve opening. Therefore, any format may be used.

  In step ST12, the gas-liquid two-phase region calculation means of the controller 11 includes the temperature obtained from the temperature detection means 9-1 and 9-2, the pressure obtained from the pressure detection means 10-1 and 10-2, Equation 3 for obtaining the gas phase portion of the refrigerant mass flow rate, Equation 4 for obtaining the liquid phase portion of the refrigerant mass flow rate, and the physical model equation expressing the state of the compressor 4, the state equation of the refrigerant that has passed through the compressor 4 Get. Similarly, the temperature obtained from the temperature detection means 9-2, 9-3, the pressure obtained from the pressure detection means 10-2, 10-3, and Equation 3 for obtaining the gas phase portion of the refrigerant mass flow rate, and the refrigerant mass From the equation 4 for obtaining the liquid phase portion of the flow rate and the physical model equation expressing the state of the refrigerant flow rate adjusting means 8, the state equation of the refrigerant that has passed through the refrigerant flow rate adjusting means 8 is obtained. Similarly, equations for obtaining the temperature obtained from the temperature detecting means 9-2, 9-3, 9-5, the pressure obtained from the pressure detecting means 10-2, 10-3, and the gas phase portion of the refrigerant mass flow rate. 3, the equation 4 for obtaining the liquid phase part of the refrigerant mass flow rate, and the physical model equation expressing the state of the evaporator 6, the state equation of the refrigerant that has passed through the evaporator 6 is obtained. Similarly, equations for obtaining the temperature obtained from the temperature detecting means 9-1, 9-3, 9-4, the pressure obtained from the pressure detecting means 10-1, 10-3, and the gas phase portion of the refrigerant mass flow rate. 3, the equation 4 for obtaining the liquid phase part of the refrigerant mass flow rate, and the physical model equation expressing the state of the condenser 2, the state equation of the refrigerant that has passed through the condenser 2 is obtained.

  The subscript g indicates the gas phase, and the subscript l indicates the liquid phase.

  Since these devices are connected, the energy of the mass flow rate of the refrigerant and the momentum of the refrigerant is stored. Therefore, with respect to the refrigerant state equation obtained above, Equation 1 which is a law of conservation of mass, Equation 2 which is a law of conservation of momentum, and Equation 5 which is a law of conservation of energy hold. Therefore, the gas-liquid two-phase region calculation means of the controller 11 uses the state equation of the refrigerant that has passed through each device as the equation 1 that is the law of conservation of mass, the equation 2 that is the law of conservation of momentum, and the law of conservation of energy. Substituting into the equation (5), the unknown is identified by system identification so that the substituted equation always holds.

At this time, the minimum required unknown is usually the dryness, but the enthalpy and temperature of the inlet and outlet of the heat exchanger (condenser 2 and evaporator 6), which are similarly unknown, It is possible to identify the length of the gas-liquid two-layer region (length in the refrigerant flow direction).
That is, since the length in the refrigerant flow direction of the evaporator 6 is known by obtaining the length of the gas-liquid two-layer region in the evaporator 6, the gas-liquid two-phase region in the evaporator 6 is known. Can be determined.

  There are various methods for identifying the unknown, but methods such as the least square method of the autoregressive moving average and the prediction error correction method may be used.

  Each physical model of the device has items of physical state values that are important in the air conditioner system, and includes, for example, refrigerant flow rate, pressure, temperature, dryness, and effective volume of the compressor 4.

  In this way, the state of each device of the air conditioner is connected, the operation of the entire air conditioner is simulated, and by grasping which part of the refrigerant is biased in which part, the outlet of the evaporator 6 is dried. And the ratio of the gas-liquid two-phase region in the evaporator 6 can be obtained.

  As described above, in the present embodiment, the degree of dryness at the outlet of the evaporator 6 and the ratio of the gas-liquid two-phase region inside the evaporator 6 are obtained based on the operation data of the refrigerant circuit and each physical model equation. For this reason, the dryness of the outlet of the evaporator 6 to be controlled and the ratio of the gas-liquid two-phase region inside the evaporator 6 can be obtained without requiring an additional sensor.

  Further, the gas-liquid two-phase region calculation means is based on the state equation of the refrigerant that has passed through each device, the refrigerant mass conservation law, the momentum conservation law, and the energy conservation law. 6 Determine the ratio of the gas-liquid two-phase region inside. The dryness of the outlet of the evaporator 6 and the ratio of the gas-liquid two-phase region inside the evaporator 6 can be obtained with high accuracy without requiring an additional sensor.

Embodiment 3 FIG.
In the third embodiment, an operation for optimizing the air conditioning operation by system identification of a physical model expression by the controller 11 and updating the parameters and the like as needed will be described.

  The controller 11 in the present embodiment corresponds to “update calculation means” in the present invention.

FIG. 7 is a flowchart showing a physical parameter identification method according to Embodiment 3 of the present invention.
In step ST13, past operation data of the air conditioning system is acquired from the data storage device of the controller 11. The operation data is a measured value of the installed sensor or a state value of the control device in the circuit of the air conditioning system. The operation data includes, for example, information on the refrigerant temperature and pressure on the inlet side and outlet side of the compressor 4, the refrigerant flow rate adjusting means 8, the condenser 2, and the evaporator 6, the rotation speed of the compressor 4, and refrigerant flow rate adjustment. Information on the opening degree of the means 8, the amount of air blown to the condenser 2, and the amount of air blown to the evaporator 6.

  For example, when the physical model of the compressor 4 is updated, the temperature detection units 9-1 and 9-2, the pressure detection units 10-1 and 10-2, and the control values (such as the rotation speed) of the compressor 4 are updated. Data. When the physical model of the refrigerant flow rate adjusting unit 8 is updated, the temperature detection units 9-2 and 9-3, the pressure detection units 10-2 and 10-3, and the control values (valves of the refrigerant flow rate adjusting unit 8) Opening data) is used. When the model of the evaporator 6 is updated, the temperature detection means 9-2, 9-3, 9-5, the pressure detection means 10-2, 10-3, and the control value (rotation) of the indoor unit blower 7 are used. Number). Moreover, when updating the model of the condenser 2, the temperature detection means 9-1, 9-3, 9-4, the pressure detection means 10-1, 10-3, and the control value (rotation) of the outdoor unit blower 1 Number).

  In step ST14, the current physical model formula is acquired from the data storage device. The current physical model formula refers to the physical model formula of the latest version of the device that has been system-identified.

  In step ST15, past operation data for an appropriate period is substituted into the latest physical model equation obtained in ST14, and each device is subject to the constraints of the refrigerant mass conservation law, momentum conservation law, and energy conservation law. Simulate the physical state (operating state). The appropriate period is a period during which the operation data can be simulated well. For example, it is preferable to use the past one to seven days.

  In ST16, the parameters of the physical model formula are identified and the physical model formula is updated so that the residual between the virtual air conditioning operation data simulated using the past data and the actually measured operation data is minimized. . As a method for minimizing the residual, a method such as a maximum likelihood method or a least square method may be used.

  In this way, by constantly updating the physical model to the latest version, it is possible to optimize the control parameters even when there are seasonal fluctuations and changes in location and user as the heat load of the air conditioning system. It becomes possible.

  As described above, in the present embodiment, the actual value of the operation data stored in the data storage device is substituted into the physical model equation of each device, and the refrigerant mass conservation law, momentum conservation law, and energy conservation law restrictions Under the conditions, the physical state of each device is simulated, and the physical model formula is updated so that the residual between the simulated physical state and the actual value of the operation data becomes small. For this reason, the physical state model of each apparatus used for the calculation which calculates | requires the dryness of the evaporator 6 exit, and the ratio of the gas-liquid two-phase area | region in the evaporator 6 can be calculated | required accurately. Therefore, without providing an additional sensor for detecting the refrigerant state inside the evaporator 6, the ratio of the gas-liquid two-phase region can be controlled while making the dryness of the outlet of the evaporator 6 equal to or higher than the reference value, and the energy consumption Efficiency can be improved.

  DESCRIPTION OF SYMBOLS 1 Outdoor unit blower, 2 Condenser, 3 Opening / closing means, 4 Compressor, 5 Refrigerant storage means, 6 Evaporator, 7 Indoor unit blower, 8 Refrigerant flow rate adjustment means, 9 Temperature detection means, 10 Pressure detection means, 11 Control controller , 12 signal lines, 13 measurement signal conveying means, 14 liquid piping, 15 gas piping, 16 indoor units, 17 outdoor units, 18 heat exchanger electric heat exchange surface, 19 liquid phase regions, 20 locations, 21 locations, 22 regions.

Claims (12)

In an air conditioner equipped with a refrigerant circuit that circulates a refrigerant by connecting a compressor, a condenser, a refrigerant flow rate adjusting means, and an evaporator sequentially by piping,
A gas-liquid two-phase region calculation means for determining the degree of dryness of the outlet of the evaporator and the ratio of the gas-liquid two-phase region inside the evaporator, based on the operating state of the refrigerant circuit;
Controlling at least one of the compressor, the refrigerant flow rate adjusting means, the amount of air blown to the condenser, and the amount of air blown to the evaporator, and setting the dryness of the outlet of the evaporator to a predetermined value or more, the gas-liquid An air conditioner comprising a control means for controlling the ratio of the two-phase region. The control means includes
The dryness at the outlet of the evaporator is a predetermined value among combinations of control values of at least the rotation speed of the compressor, the opening of the refrigerant flow rate adjusting means, the air flow rate to the condenser, and the air flow rate to the evaporator. Find the combination of control values
Based on the combination of control values in which the ratio of the gas-liquid two-phase region in the evaporator is maximized among the combinations of the control values, the amount of air blown to the compressor, the refrigerant flow rate adjusting means, the condenser, and the The air conditioner according to claim 1, wherein at least one of the airflows to the evaporator is controlled. At least storage means storing physical model equation information that simulates the physical state of the compressor, the refrigerant flow rate adjusting means, the condenser, and the evaporator,
The gas-liquid two-phase region calculation means is
3. The dryness at the outlet of the evaporator and the ratio of the gas-liquid two-phase region inside the evaporator are obtained based on the operation data of the refrigerant circuit and the physical model equations. Air conditioner. The gas-liquid two-phase region calculation means is
The state of the refrigerant that has passed through the compressor based on the refrigerant temperature and pressure on the suction side of the compressor, the refrigerant temperature and pressure on the discharge side, the rotational speed of the compressor, and the physical model equation of the compressor Find the formula
The state of the refrigerant that has passed through the condenser based on the refrigerant temperature and pressure on the inlet side of the condenser, the refrigerant temperature and pressure on the outlet side, the amount of air blown to the condenser, and the physical model equation of the condenser Find the formula
Based on the refrigerant temperature and pressure on the inlet side of the refrigerant flow rate adjusting means, the refrigerant temperature and pressure on the outlet side, the opening degree of the refrigerant flow rate adjusting means, and the physical model formula of the refrigerant flow rate adjusting means, the refrigerant flow rate Find the equation of state of the refrigerant that passed through the adjusting means,
The state of the refrigerant that has passed through the evaporator based on the refrigerant temperature and pressure on the inlet side of the evaporator, the refrigerant temperature and pressure on the outlet side, the amount of air blown to the evaporator, and the physical model equation of the evaporator Find the formula
The degree of dryness at the outlet of the evaporator and the ratio of the gas-liquid two-phase region inside the evaporator are obtained based on the state equations and the mass conservation law, momentum conservation law, and energy conservation law of the refrigerant. The air conditioner according to claim 3. Data storage means for storing information on the actual value of the operation data of the refrigerant circuit;
Substituting the actual value of the operation data stored in the data storage means into the physical model formula of each device stored in the storage means, and the constraint conditions of the refrigerant mass conservation law, momentum conservation law and energy conservation law To simulate the physical state of each device,
The update calculation means which updates the said physical model formula so that the residual of the simulated physical state and the actual value of the said operation data may become small is provided, The any one of Claims 1-4 characterized by the above-mentioned. Air conditioner as described in. The operation data is
Information on refrigerant temperature and pressure on the inlet side and outlet side of the compressor, the refrigerant flow rate adjusting means, the condenser, and the evaporator; and
6. The air conditioner according to claim 3, wherein the air conditioner has information on rotation speed of the compressor, opening degree of the refrigerant flow rate adjusting means, air flow rate to the condenser, and air flow rate to the evaporator. . A control method for an air conditioner including a refrigerant circuit for circulating a refrigerant by connecting a compressor, a condenser, a refrigerant flow rate adjusting unit, and an evaporator sequentially by piping,
A gas-liquid two-phase region calculation step for determining the dryness of the outlet of the evaporator and the ratio of the gas-liquid two-phase region inside the evaporator, based on the operating state of the refrigerant circuit;
Controlling at least one of the compressor, the refrigerant flow rate adjusting means, the amount of air blown to the condenser, and the amount of air blown to the evaporator, and setting the dryness of the outlet of the evaporator to a predetermined value or more, the gas-liquid And a control step for controlling the ratio of the two-phase region. The control step includes
The dryness at the outlet of the evaporator is a predetermined value among combinations of control values of at least the rotation speed of the compressor, the opening of the refrigerant flow rate adjusting means, the air flow rate to the condenser, and the air flow rate to the evaporator. Obtaining a combination of control values as described above;
Of the combination of control values at which the degree of dryness at the outlet of the evaporator becomes a predetermined value or more, obtaining a combination of control values that maximizes the ratio of the gas-liquid two-phase region inside the evaporator;
A step of controlling at least one of the compressor, the refrigerant flow rate adjusting means, the amount of air blown to the condenser, and the amount of air blown to the evaporator based on a combination of control values that maximizes the ratio of the gas-liquid two-phase region; The method for controlling an air conditioner according to claim 7, wherein: The gas-liquid two-phase region calculation step includes:
8. The dryness of the evaporator outlet and the ratio of the gas-liquid two-phase region inside the evaporator are obtained based on the operation data of the refrigerant circuit and the physical model formula of each device. The control method of the air conditioner of Claim 8. The gas-liquid two-phase region calculation step includes:
The state of the refrigerant that has passed through the compressor based on the refrigerant temperature and pressure on the suction side of the compressor, the refrigerant temperature and pressure on the discharge side, the rotational speed of the compressor, and the physical model equation of the compressor Obtaining an expression; and
The state of the refrigerant that has passed through the condenser based on the refrigerant temperature and pressure on the inlet side of the condenser, the refrigerant temperature and pressure on the outlet side, the amount of air blown to the condenser, and the physical model equation of the condenser Obtaining an expression; and
Based on the refrigerant temperature and pressure on the inlet side of the refrigerant flow rate adjusting means, the refrigerant temperature and pressure on the outlet side, the opening degree of the refrigerant flow rate adjusting means, and the physical model formula of the refrigerant flow rate adjusting means, the refrigerant flow rate Obtaining a state equation of the refrigerant that has passed through the adjusting means;
The state of the refrigerant that has passed through the evaporator based on the refrigerant temperature and pressure on the inlet side of the evaporator, the refrigerant temperature and pressure on the outlet side, the amount of air blown to the evaporator, and the physical model equation of the evaporator Obtaining an expression; and
Based on the state equations and the refrigerant mass conservation law, momentum conservation law, and energy conservation law, determining the dryness of the evaporator outlet and the ratio of the gas-liquid two-phase region inside the evaporator; The method of controlling an air conditioner according to claim 9, comprising: A data accumulation step for storing information on the actual value of the operation data of the refrigerant circuit;
Substituting the actual value of the operation data into the physical model formula of each device, and simulating the physical state of each device under the constraints of the refrigerant mass conservation law, momentum conservation law and energy conservation law;
The update calculation step of updating the physical model formula so as to reduce a residual between the simulated physical state and the actual value of the operation data. The air conditioner control method described. The operation data is
Information on refrigerant temperature and pressure on the inlet side and outlet side of the compressor, the refrigerant flow rate adjusting means, the condenser, and the evaporator; and
The air conditioner according to claim 9 or 11, comprising information on a rotation speed of the compressor, an opening degree of the refrigerant flow rate adjusting unit, an air flow rate to the condenser, and an air flow rate to the evaporator. Control method.

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