JPH0157267B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in variable air volume methods in air conditioning.

(Prior Art) Conventionally, as shown in FIG. 1, in an air conditioning system, indoor thermostats 2,..., 2 are used to control air ducts 3,..., 2 according to load fluctuations in each of a plurality of rooms 1,..., 1. 3 variable air volume machine (VAV) 4,...,
An opening/closing control signal is sent to variable air volume machine 4,
..., 4 opens and closes and the air volume fluctuates, and in order to minimize the static pressure inside the duct that fluctuates accordingly, the static pressure sensor 7 in the blower duct 3 at the end of the blower 5 and the exhaust fan 6 adjusts it. A variable air volume method in which an air volume control signal is sent through a device 8, and the rotation speed of the blower 5 and the exhaust fan 6 is controlled through the respective inverters 9 and 10, so that the air volume and exhaust volume are adjusted. has been put into practical use. Note that 11 is an air conditioner including a blower 5 and an exhaust fan 6, 12 is a heating coil, 13 is a cooling coil, 14 and 15 are filters, 16 is an adjustment damper, 17 is an outside air intake damper,
18 is an exhaust damper. In addition, variable air volume machine 4
When the static pressure inside the duct is high, the throttle is increased and its own pressure loss increases, but when the static pressure inside the duct is low, the throttle is decreased and its own pressure loss is reduced. In other words, regardless of fluctuations in the static pressure inside the duct,
This is a device that ensures a predetermined air volume.

By the way, in the conventional variable air volume method described above, it is necessary to install the static pressure sensor 7 inside the blower duct 3 separately from the air conditioner 11, and in addition, installing it at the end of the blower duct 3 requires on-site work such as long wiring work. It is. Furthermore, depending on the mounting position of the static pressure sensor 7, control accuracy may be poor, and sufficient consideration must be given to the mounting position. Furthermore, static pressure sensor 7
Because only so-called static pressure control was used, it was difficult to balance the supply and exhaust volumes, and when the supply and exhaust volumes were unbalanced, the indoor pressure fluctuated greatly, and if the indoor pressure became negative pressure. When outside air enters and the indoor pressure becomes high, indoor air flows out, and in either case, the problem of increased heat load is unavoidable. Additionally, buildings that do not like rapid pressure fluctuations in the room require a separate compensation control device.

(Objective of the Invention) The basic object of the present invention is to almost completely balance the air volume of the air supply/exhaust system to stabilize indoor pressure and to save energy.

(Structure of the Invention) For this reason, the present invention provides an air supply air velocity sensor that detects the amount of air passing through the supply air and an exhaust air velocity sensor that detects the amount of air that passes through the exhaust air at sufficiently rectified positions in the air supply system and the exhaust system. Each sensor is installed, and the relationship between the air flow rate and the static pressure inside the duct is determined in advance when the blower is controlled, and a curve is set by adding the minimum necessary static pressure to the device resistance. The intersection point between the detected air volume value and the above curve is determined, and a supply air volume control signal corresponding to this intersection point is sent to the above blower, and the detection signals from each wind speed sensor are compared to set each passing air volume in advance. The exhaust fan is configured to send an exhaust air volume control signal to the exhaust fan to control the rotation speed so that it falls within the set value range set by the exhaust fan.

Then, while controlling the rotation speed of the blower using the detection signal from the supply air speed sensor, a microcomputer or other device compares the same type of detection signal of the amount of air passing through the supply air by the intake air speed sensor and the amount of air passing through the exhaust air from the exhaust air speed sensor. By controlling the air volume by controlling the rotation speed of the exhaust fan, the air volume of the air supply and exhaust system can be almost perfectly balanced.

(Effects of the Invention) According to the present invention, the air volume control of the blower and exhaust fan using air supply and exhaust air volume sensors improves responsiveness and improves control accuracy compared to static pressure control alone. Since the amount of air supply and exhaust is also good, it is possible to almost perfectly balance the supply and exhaust amounts. Therefore,
There is no need for a conventional pressure fluctuation compensation control device.

Additionally, since static pressure sensors do not require long control piping, on-site work such as piping work is no longer required. Furthermore, the energy saving rate does not vary depending on the installation position and setting value of the wind speed sensor, and control can always be performed well.

(Example) The same structure and function as the conventional technology shown in Fig. 1 are as follows:
The same numbers will be given and explanations will be omitted.

In FIG. 2, the supply air speed sensor V _S and the exhaust air speed sensor V _R are installed in the air conditioner 11 at a position where the air supply and exhaust air from the air supply system and the exhaust system are sufficiently rectified.

The supply air wind speed sensor V _S of the supply air system is preferably installed downstream of the filter 14 because the air is most rectified at this position.

Since the exhaust air velocity sensor V _R of the exhaust system is most rectified downstream of the filter 15, it is preferable to install it at this position.

Each wind speed sensor V _S , _VR is connected to a microcomputer 22 , and after the detection signal of each wind speed sensor V _S , _VR is processed by the microcomputer 22 , each inverter 9 , 1 of the blower 5 and exhaust fan 6 is connected to the microcomputer 22 .
0 as an air volume control signal, the rotational speed is controlled, and the air volume and exhaust volume are varied.

The microcomputer 22 is set as follows after the air conditioner 11 is installed on site (see FIG. 3).

(Setting 0) Input the relationship between the control voltage E and the output frequency H of the inverters 9 and 10.

E=aH+b (a and b are constants) (Setting 1) Input the passage cross-sectional areas K _S and K _R at the set positions of each wind speed sensor V _S and V _R.

(Setting 2) Enter the relationship between the static pressure, air volume, and frequency of the blower and exhaust fans 5 and 6.

(Setting 3) Enter the relationship between pressure loss and air volume within the air conditioner 11. (Air supply side only) Curve <Sx=
Let fx(Q)>.

(Setting 4) Resistance curve of duct system <Sy=fy(Q)
> (Relationship between air volume and pressure loss).

(Setting 5) Input the minimum operating static pressure P of the variable air volume fan 5.

(Setting 6) Upper limit value Y ₁ , lower limit value of supply/exhaust air volume ratio
Set _Y2 . (The actual supply/exhaust air volume ratio is controlled between these set values.) Y ₁ , Y ₂ = exhaust air volume/supply air volume The microcomputer 22 above controls the blower 5 and exhaust fan 6 as follows. Ru.

(1) Input the wind speed V _S from the wind speed sensor V _S.

(2) Calculate the supply air volume Q _S from the wind speed value v _s (Q _S =
_{K.S.vs )} .

Substitute Q=Q _S , calculate Sx, Sy, and get Sz=
Find Sx + Sy + Pv.

Set the frequency where S=S _Z and Q=Q _S (setting 2)
Let the obtained frequency be H. A control voltage Es corresponding to this H is output to the inverter 9 of the blower 5.

(3) Input the wind speed v _r from the wind speed sensor V _R.

(4) Calculate the exhaust air volume Q _R from the wind speed value v _r (Q _R =
_KR・_vr ).

(5) Calculate the supply/exhaust air volume ratio X (X=Q _R /Q _S ).

(6) Compare the current air volume value X with the set values Y ₁ and Y ₂ (Y ₂ ≦X≦Y ₁ ).

(6-1) If the current air volume ratio exceeds the set value (X>Y ₁ ), lower the inverter control voltage of the exhaust fan 6 to lower the exhaust side frequency and reduce the exhaust air volume.

(6-2) If the current air volume ratio is less than the set value (X<
Y ₂ ), the inverter control voltage of the exhaust fan 6 is increased to increase the exhaust side frequency and increase the exhaust air volume.

That is, in response to load fluctuations in the room 1, the indoor thermostat 2 sends an opening/closing control signal to the variable air volume fan 4 at the end of the ventilation duct 3, and the variable air volume fan 4 opens and closes to fluctuate the air volume. In order to minimize the static pressure inside the duct, the air supply wind speed sensor V _S detects the wind speed V _S corresponding to the fluctuated air supply amount Q _S of the blower 5.

For example, as shown in Figure 4, the cutest point (Q _S1 ,
S ₁ ) is moved to two points (Q _S2 , S ₂ ) by restricting the variable air volume unit 4, the air supply air speed sensor V _S changes the air speed v _s2 corresponding to the air volume Q _S2 . It detects it. Next, the microcomputer 22 calculates the calculated air volume of the blower 5.
The three points (Q _S2 , S ₃ ) that are the intersections of Q _S2 and the curve Sz, which is the sum of the minimum required static pressure and the resistance of the air supply system, are found, and the rotational speed of the blower 5 corresponding to these three points is calculated. A control signal is sent to the air supply blower inverter 9, and the blower 5 is controlled to have three operating points. At the same time, the variable air volume machine 4 automatically opens and closes to adjust the air volume.

Next, the exhaust air speed sensor V _R detects the wind speed v _r corresponding to the exhaust air volume Q _R of the exhaust fan 6, and its signal is compared in the microcomputer 22 with the signal detected by the supply air speed sensor. A control signal is sent to the exhaust fan 6 to control its rotation speed so that each amount of passing air falls within a preset value range.

For example, as shown in FIG. 5, when the air blower 5 changes from Q _S1 to Q S2 due to the throttle of the variable air volume fan 4, the exhaust air volume is the air volume Q _R1 before the throttle of the variable air volume fan ₄ . , the supply/exhaust air volume ratio X is X=Q _R1 /
Q _S1 , and the air volume exceeds the set value (X>Y ₁ ),
The supply and exhaust air volume becomes unbalanced.

Therefore, the microcomputer 22 sends a control signal to the inverter 10 of the exhaust fan 6 to control the rotation speed so that the supply/exhaust air volume ratio X falls within the upper and lower limits of the air volume ratio setting value. Decrease exhaust air volume.

In addition, the above example is when the variable air volume fan is closed; on the other hand, when it opens, its operation is as shown in the flow shown in Fig. 3, where the air blower 5 is first controlled by the detection of the air supply air speed sensor V _S. Corresponding to the amount of control,
The exhaust fan 6 is controlled to balance the amount of air supply and exhaust.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional variable air volume method, Fig. 2 is an explanatory diagram of a variable air volume method according to the present invention, Fig. 3 is a control flowchart by a computer, and Fig. 4 is a graph showing air volume control of a blower. FIG. 5 is a graph showing the air volume control of the exhaust fan. 1...Indoor, 2...Indoor thermostat, 3...Blower duct, 4...Variable air volume machine, 5...Blower, 6...
Exhaust fan, 9, 10... Inverter, 11... Air conditioner, 22... Microcomputer, V _S ...
...Intake air speed sensor, V _R ...Exhaust air speed sensor.

Claims (1)

[Claims] 1. In response to indoor load fluctuations, the indoor thermostat sends an opening/closing control signal to the variable air volume machine at the end of the duct, and this variable air volume machine opens and closes to fluctuate the air volume. A variable air volume method in which an air volume control signal is sent to a blower and an exhaust fan in order to minimize static pressure, and the blower and exhaust fan are controlled to vary the air volume and exhaust volume, A supply air speed sensor that detects the amount of air passing through the supply air and an exhaust air speed sensor that detects the amount of air that passes through the exhaust air are installed at the sufficiently rectified positions of the air supply system and the exhaust system, respectively, and the blower is controlled in advance. Find the relationship between the air flow rate and the static pressure inside the duct when is determined, and a supply air volume control signal corresponding to this intersection is sent to the blower, and the detection signals from each wind speed sensor are compared to ensure that each passing air volume is within a preset value range. A variable air volume method for air conditioning, characterized in that an exhaust air volume control signal for controlling the rotation speed is sent to the exhaust fan.