JP4177600B2 - Air conditioning control method and air conditioning control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioning control method and an air conditioning control device that control the temperature and humidity of air supply to a room.
[0002]
[Prior art]
FIG. 4 shows an outline of an air conditioning control device that controls the temperature and humidity of the air supply to the room. In the figure, 1 is an air conditioner, 2 is a controlled room (indoor) that receives supply of air supply from the air conditioner 1, 3 is a controller, and 4 is an air supply that detects the temperature of the supply air to the controlled room 2. A temperature sensor 5 is a return air humidity sensor that detects the humidity of the return air from the controlled room 2, 6 is a cold water valve, and 7 is a hot water valve.
[0003]
The air conditioner 1 includes a cooling heat exchanger (cooling coil) 1-1, a heating heat exchanger (heating coil) 1-2, a humidifier 1-3, and a blower 1-4. . The cold water valve 6 is provided in the cold water supply passage to the cooling coil 1-1. The hot water valve 7 is provided in a hot water supply passage to the heating coil 1-2. Hereinafter, the cooling coil 1-1 and the heating coil 1-2 are collectively referred to as a heat exchanger 1-5.
[0004]
There are various types of humidifiers such as steam, vaporization, and ultrasonic. Of these, vaporizing humidifiers are most often used. In this example, it is assumed that the humidifier 1-3 is a vaporizing humidifier. The vaporizing humidifier increases the amount of moisture contained in the passing air by vaporizing the moisture. The air state change at this time is an adiabatic (isoenthalpy) change. Therefore, the temperature of the passing air decreases according to the amount of evaporated water. The vaporizing humidifier is controlled by ON / OFF (start / stop).
[0005]
In this air conditioning control device, the controller 3 is set with a target value tsp for the supply air temperature and a target value RHsp for the return air humidity. The controller 3 controls the amount of cold / warm water (valve opening degree) to the heat exchanger 1-5 so that the measured value tpv of the supply air temperature from the supply air temperature sensor 4 matches the target value tsp. That is, the supply air temperature (tpv) to the controlled chamber 2 is feedback-controlled so that tpv and tsp match. Further, the measured value RHpv of the return air humidity from the return air humidity sensor 5 is compared with the target value RHsp, and when the RHpv falls below RHsp, the humidifier 1-3 is activated. That is, the humidifier 1-3 is turned on, and the amount of moisture (humidity) contained in the supply air is controlled so that RHpv does not fall below RHsp.
[0006]
[Problems to be solved by the invention]
When the humidifier 1-3 is activated, water supply to the humidifier starts immediately, moisture is vaporized, and the amount of moisture contained in the passing air increases. Thereby, the temperature of passing air falls and the supply air temperature to the controlled chamber 2 falls rapidly. This temperature drop of the passing air due to an increase in the amount of moisture contained in the passing air is called a vaporization cooling effect. The evaporative cooling effect of the humidifier 1-3 acts as a disturbance to the control of the supply air temperature.
[0007]
FIG. 5 shows changes in air inlet temperature to the humidifier 1-3 and air outlet temperature from the humidifier 1-3 (step response) when the humidifier 1-3 is turned ON / OFF. In the same figure, I shows ON / OFF of the humidifier 1-3, II shows the inlet temperature of the air to the humidifier 1-3, III shows the outlet temperature of the air from the humidifier 1-3. As can be seen from the response result, when the humidifier 1-3 is activated during the period from T1 to T2, the outlet temperature of the air from the humidifier 1-3 is drastically lowered due to the evaporative cooling effect. That is, it can be seen that the evaporative cooling effect of the humidifier 1-3 works as a disturbance to the control of the supply air temperature.
[0008]
FIG. 6 is a control block diagram of the air conditioning control device shown in FIG. In the figure, 8 is a supply air temperature control block, and 9 is a humidity control block.
In the supply air temperature control block 8, the measured value tpv of the supply air temperature is fed back to the error calculator 8-1 to obtain a difference from the target value tsp of the supply air temperature, and the difference between the measured value tpv and the target value tsp. Is supplied to the PID calculation unit 8-2 to obtain an operation amount (valve opening degree) to the heat exchanger 1-5, and an air supply temperature (control amount) that is an output value of the air conditioning process 8-3 is determined by this operation amount. Control.
[0009]
The humidity control block 9 feeds back the measured value RHpv of the return air humidity to the error calculation unit 9-1 to obtain a difference from the target value RHsp of the return air humidity, and turns on the difference between the measured value RHpv and the target value RHsp. To / OFF control section 9-2. The ON / OFF control unit 9-2 gives an ON command to the humidifier 1-3 at least while the measured value RHpv is lower than the target value RHsp, and turns the ON command OFF when the target value RHsp is exceeded. The humidity (control amount), which is the output value of the air conditioning process 9-3, is controlled by this ON / OFF command.
[0010]
In the feedback control of the supply air temperature in the supply air temperature control block 8, the influence of the operation amount (valve) is not changed until the supply air temperature (control amount) changes (a difference between the measured value tpv and the target value tsp occurs). (Opening). In the air conditioning control, a time delay until the change in the operation amount is reflected as the change in the control amount cannot be ignored. Therefore, it cannot immediately respond to a sudden disturbance change due to the evaporative cooling effect of the humidifier 1-3.
[0011]
It is possible to increase the sensitivity of feedback control and shorten the response time by adjusting the parameters in the PID calculation unit 8-2. However, there is a possibility that overshoot or hunting of the operation end may occur. is not.
[0012]
The present invention has been made to solve such a problem, and the object of the present invention is to provide a stable supply air temperature control in response to a sudden disturbance change due to the evaporative cooling effect of the humidifier. Another object is to provide an air conditioning control method and an air conditioning control device.
[0013]
[Means for Solving the Problems]
In order to achieve such an object, the present invention obtains an operation amount corresponding to the difference between the measured value of the supply air temperature and the target value, and based on this operation amount, the measured value of the supply air temperature and the target value are obtained. When the humidifier that increases the amount of water contained in the indoor air supply is activated while controlling the temperature of the indoor air supply so as to match, the air supply by the evaporative cooling effect generated by the activation of this humidifier A canceling operation amount that cancels the decrease in temperature is predicted, and this canceling operation amount is added to an operation amount corresponding to the difference between the measured value of the supply air temperature and the target value.
[0014]
According to the present invention, when the humidifier is started, the canceling operation amount that cancels the decrease in the supply air temperature due to the evaporative cooling effect generated by the start of the humidifier is predicted, and this canceling operation amount is equal to the supply air temperature. It is added to the manipulated variable according to the difference between the measured value and the target value. Thereby, the disturbance due to the evaporative cooling effect of the humidifier is canceled ahead of time before affecting the system. That is, in the present invention, when the humidifier is started, in addition to feedback control for matching the measured value of the supply air temperature with the target value, the operation amount according to the difference between the measured value of the supply air temperature and the target value is set. Feedforward control with offset operation amount is performed, and constant value control of supply air temperature is performed by feedback control, while disturbance suppression that cancels the decrease in supply air temperature due to the evaporative cooling effect of the humidifier by feedforward control Is implemented.
[0015]
The canceling operation amount is a transfer function representing the evaporative cooling effect generated by the activation of the humidifier, G (s), and the operation amount according to the difference between the measured value of the supply air temperature and the target value and the supply air temperature. When the transfer function representing the relationship is P (s), it is obtained by a prediction model having the transfer function F (s) set as F (s) = G (s) / P (s).
[0016]
In the case of supply air temperature control, P (s) and G (s) can be estimated from equipment specifications (coil cooling / heating capacity, humidification amount, water supply amount) and the like. If the change in the supply air temperature (F (s) * P (s)) and the evaporative cooling effect due to the canceling operation amount can be operated, that is, F (s) * P (s) -G (s) = 0 holds. Thus, the influence of disturbance on the supply air temperature is zero. Therefore, if P (s) and G (s) are obtained and the canceling operation amount is obtained by a prediction model in which F (s) is set as F (s) = G (s) / P (s), this canceling operation is obtained. By adding the amount to the operation amount corresponding to the difference between the measured value of the supply air temperature and the target value, a decrease in the supply air temperature that would be caused by the evaporative cooling effect of the humidifier is suppressed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a control block diagram of an air-conditioning control apparatus showing an embodiment of the present invention, and a supply air temperature control block is extracted and shown as a characteristic part. In the figure, the same reference numerals as those in FIG. 6 denote the same or equivalent components.
[0018]
In this supply air temperature control block 8 ′, an FF model (prediction model) 8-4 that predicts a canceling operation amount that cancels a decrease in supply air temperature due to the evaporative cooling effect generated by the activation of the vaporizing humidifier 1-3. The amount of canceling operation from the FF model 8-4 is given to the adder 8-5, and the amount of canceling operation from the FF model 8-4 is added to the amount of operation from the PID calculation unit 8-2 to perform heat exchange. It is set as the operation amount (valve opening degree) to the device 1-5.
[0019]
In FIG. 1, reference numeral 8-6 denotes a disturbance model indicating a disturbance that the evaporative cooling effect generated by the activation of the humidifier 1-3 gives to the supply air temperature (control amount). F (s) is a transfer function in the FF model 8-4, G (s) is a transfer function in the disturbance model 8-6, and P (s) is a transfer function in the air conditioning process 8-3. G (s) represents the evaporative cooling effect generated by the activation of the humidifier 1-3, and P (s) represents the relationship between the operation amount and the supply air temperature in the air conditioning process 8-3.
[0020]
[Setting of transfer function F (s) to prediction model]
FIG. 2 shows an equivalent block diagram of FIG. The FF model 8-4 and the disturbance model 8-6 in FIG. 1 can be replaced with a model 8-7 whose transfer function is “F (s) * P (s) −G (s)”. In this equivalent block diagram, if F (s) * P (s) -G (s) = 0 holds, the influence of disturbance on the supply air temperature becomes zero. That is, if F (s) = G (s) / P (s) is established, the influence of the disturbance on the supply air temperature becomes zero.
[0021]
Therefore, in the present embodiment, P (s) and G (s) are obtained, and the transfer function F (s) in the prediction model 8-4 is set as F (s) = G (s) / P (s). By doing so, the influence of the disturbance on the supply air temperature is made zero.
[0022]
In the case of indoor temperature control and return air temperature control, it is not easy to obtain P (s) and G (s) because it is affected by indoor heat load (lighting, human body, equipment heat generation), outside air temperature, solar radiation amount, etc. Absent. On the other hand, in the supply air temperature control, P (s) and G (s) can be accurately obtained.
[0023]
In the supply air temperature control, when P (s) and G (s) are expressed by “gain”, “first-order lag”, and “dead time”, the following equations (1) and (2) are obtained, respectively. . In these equations, Kp and Kg are gains, Tp and Tg are first-order delays, Lp and Lg are dead times, and can be known from the design conditions and step response of the air conditioner.
P (s) = Kp / (1 + Tp * s) e ^{−Lp * s} (1)
G (s) = Kg / (1 + Tg * s) e ^{−Lg * s} (2)
[0024]
From this P (s) and G (s), the transfer function F (s) is
F (s) = (Kg / Kp) * {(1 + Tp * s) / (1 + Tg * s)} e ^{− (Lg−Lp) * s} (3)
And set to the FF model 8-4.
[0025]
[Feedback control and feedforward control]
In FIG. 1, when the humidifier 1-3 is activated, the prediction model 8-4 is informed that the humidifier 1-3 is activated. The prediction model 8-4 uses the transfer function F (s) set by the above equation (3) to cancel the reduction in supply air temperature due to the evaporative cooling effect generated by the activation of the humidifier 1-3. , And this canceling operation amount is given to the adder 8-5. The adder 8-5 adds the canceling operation amount from the prediction model 8-4 to the operation amount from the PID calculation unit 8-2 to obtain the operation amount to the heat exchanger 1-5. When the humidifier 1-3 is OFF, the canceling operation amount from the prediction model 8-4 is zero.
[0026]
Thereby, the disturbance by the vaporization cooling effect of the humidifier 1-3 is canceled ahead of time before affecting the system. That is, in the present embodiment, when the humidifier 1-3 is activated, in addition to the feedback control for matching the measured value tpv of the supply air temperature with the target value tsp, the measured value tpv of the supply air temperature and the target value tsp. The feedforward control is performed by adding the offset operation amount to the operation amount according to the difference between the two and the feed air temperature, and the feed air temperature is controlled by the feedback control. On the other hand, the feed forward control is performed by the evaporative cooling effect of the humidifier. Disturbance suppression that cancels the decrease in the air temperature is performed. Accordingly, it is possible to provide a stable supply air temperature control in response to a sudden disturbance change due to the evaporative cooling effect of the humidifier 1-3.
[0027]
The waveform of the FF control component by F (s) will be described. Assuming that Kp = 10, Tp = 200, Lp = 50, Kg = 5, and Lg = 50, Tg = 50, 100, 200, 300, and 1000, the waveform of the FF control component when changing is seen. Since the dead time is the same, it is canceled out, and the waveform is as shown in the graph of FIG. As can be seen from the equation of F (s), the FF control component is asymptotic to (KpTp / GpTg). When the disturbance delay time is smaller than the process delay time, the FF control component has a steep waveform with decreasing asymptotics (Tg = 50, 100). On the other hand, when the disturbance delay time is larger than the process delay time, the FF control component has a gentle waveform that gradually increases (Tg = 300, 1000). Incidentally, when the process delay time and the disturbance delay time are equal, a constant FF control component (Tg = 200) is obtained.
[0028]
【The invention's effect】
As is apparent from the above description, according to the present invention, when the humidifier is started, in addition to the feedback control for matching the measured value of the supply air temperature with the target value, the measured value of the supply air temperature and the target value. The feedforward control is performed by adding the offset operation amount to the operation amount according to the difference between the two and the feed air temperature, and the feed air temperature is controlled by the feedback control. On the other hand, the feed forward control is performed by the evaporative cooling effect of the humidifier. Disturbance suppression that cancels the decrease in the air temperature is performed, and it is possible to provide a stable supply air temperature control in response to a sudden disturbance change due to the evaporative cooling effect of the humidifier.
[Brief description of the drawings]
FIG. 1 is a control block diagram of an air-conditioning control apparatus showing an embodiment of the present invention.
FIG. 2 is an equivalent block diagram of FIG.
FIG. 3 is a diagram illustrating a waveform example of an FF control component.
FIG. 4 is an instrumentation diagram showing an outline of an air conditioning control device that controls the temperature and humidity of the air supply to the room.
FIG. 5 is a diagram showing changes in inlet temperature and outlet temperature (step response) when the humidifier is turned ON / OFF.
6 is a control block diagram of the air conditioning control device shown in FIG. 4. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air conditioner, 1-1 ... Cooling coil, 1-2 ... Heating coil, 1-3 ... Humidifier, 1-4 ... Blower, 1-5 ... Heat exchanger, 2 ... Controlled room (indoor), 3 ... Controller, 4 ... Supply air temperature sensor, 5 ... Return air humidity sensor, 6 ... Cold water valve, 7 ... Hot water valve, 8 '... Supply air temperature control block, 8-1 ... Error calculation unit, 8-2 ... PID calculation Part, 8-3 ... air conditioning process, 8-4 ... FF model (prediction model), 8-5 ... adder, 8-6 ... disturbance model.

Claims (4)

In the air conditioning control method for controlling the temperature and humidity of the air supply to the room,
Measure the temperature of the air supply to the room,
Obtain the manipulated variable according to the difference between the measured value of the supply air temperature and the target value.
Based on this manipulated variable, while controlling the supply air temperature to the room so that the measured value of the supply air temperature and the target value match,
When a humidifier that increases the amount of water contained in the indoor air supply is activated, an offset operation amount that offsets a decrease in the supply air temperature due to the evaporative cooling effect generated by the activation of the humidifier is predicted. An air conditioning control method characterized in that a canceling operation amount is added to an operation amount corresponding to a difference between a measured value of the supply air temperature and a target value. In the air-conditioning control method according to claim 1,
A transfer function representing the evaporative cooling effect generated by the activation of the humidifier is G (s), and a transfer function representing the relationship between the manipulated variable and the supply air temperature according to the difference between the measured value of the supply air temperature and the target value. Air-conditioning control method, wherein the offset operation amount is obtained by a prediction model having a transfer function F (s) such that F (s) = G (s) / P (s) . In the air conditioning control device that controls the temperature and humidity of the air supply to the room,
Supply air temperature measuring means for measuring the temperature of the supply air into the room;
An operation amount corresponding to the difference between the measured value of the supply air temperature measured by the supply air temperature measuring means and the target value is obtained, and the measured value of the supply air temperature matches the target value based on the operation amount. Feedback means for controlling the supply air temperature into the room,
A humidifier for increasing the amount of water contained in the indoor air supply;
When this humidifier is started, a canceling operation amount that cancels the decrease in the supply air temperature due to the evaporative cooling effect generated by the start of this humidifier is predicted, and this canceling operation amount is calculated based on the measured value of the supply air temperature and the target An air-conditioning control apparatus comprising feedforward means for adding an operation amount according to a difference from a value. In the air conditioning control device according to claim 3,
The feedforward means includes a prediction model for obtaining the canceling operation amount, and a transfer function representing an evaporative cooling effect generated by activation of the humidifier is expressed as G (s), a measured value of the supply air temperature, and a target value. When the transfer function representing the relationship between the manipulated variable according to the difference and the supply air temperature is P (s), the transfer function F (s) of the prediction model is F (s) = G (s) / P (s ) Is set as the air conditioning control device.

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