JPH05223328A - Method for controlling air volume in centralized type air-conditioning equipment - Google Patents

Abstract

PURPOSE:To control the volume of air from an air-conditioning machine appropriately in accordance with the quantitative requirements of rooms for the air and in an energy-saving, noise-reducing manner in the operation of centralized type air-conditioning equipment distributing air from the air-conditioning machine through a plurality of branch ducts to the rooms. CONSTITUTION:Both the upper limit and the lower limit of each range of air velocity in which, for a rate of revolution of a blower 6 in an air-conditioning machine 1, air maintains a specified static pressure are stored in a control unit 8. The air velocity detected by an air-velocity sensor 9 which is positioned close to the blower 6 in an air-supply duct 11 is inputted to the control unit 8 and, when the inputted value is greater than said upper limit of air velocity, the rate of revolution of the blower 6 is increased, whereas, when the inputted value is less than said lower limit of air velocity, the rate of revolution of the blower 6 is decreased. Thus the rate of revolution of the blower 6 is so controlled as to bring the air velocity detected by the air-velocity sensor between the upper limit and the lower limit of air velocity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centralized air conditioner for distributing air sent from an air conditioner into a room through a plurality of branch ducts, and responding to fluctuations in the supply air volume of each branch duct. The present invention relates to a method of controlling the air flow rate of

[0002]

2. Description of the Related Art An air conditioner having a cooler, a heater, a blower, etc. is installed at one or more places of a building to cool or heat outside air, return air or mixed air thereof.
Centralized air conditioning equipment that distributes and supplies air into a room from outlets of terminals of a plurality of branch ducts branched from an air supply duct is well known.

In this equipment, in order to maintain the temperature of each room or the temperature of different places in the same room at a desired specified temperature, an air flow sensor, a damper, a damper opening / closing motor,
A terminal control unit with an electronic control circuit is installed for each branch duct, and the supplied air volume detected by the air volume sensor is compared with the required air volume required to maintain the desired specified temperature by the electronic control circuit, and the supplied air volume is Sending a drive signal for opening and closing the damper to the required air volume to the damper opening / closing motor, and sending the damper full open position signal and the comparison value to the rotation speed control device of the air conditioner to control the rotation speed of the blower. Are disclosed in Japanese Examined Patent Publication No. 60-47497.

According to the air flow rate control technique disclosed in the above publication, when the dampers of all the terminal control units are not fully opened, it is determined that there is a surplus in the air flow rate, and the rotation speed of the blower is reduced. When the supply air volume of a certain branch duct becomes insufficient, the opening of the damper is increased to make up for the shortage, and even if the damper is fully opened, the blower rotation will not start until the supply air volume is insufficient. I try to increase the speed.

That is, the operating condition of the blower is set on the basis of the fully opened state of the damper, and the blower is operated in a state in which the amount of blown air is always insufficient, so operating energy can be saved, but the state of each terminal control unit can be reduced. Are individually sent to the rotation speed control device to judge whether the air flow is excessive or insufficient, and the rotation speed of the blower is increased or decreased.Therefore, it is necessary not only to use long wiring for signal transmission, but also to change the rotation speed. The system for determining whether is complicated.

On the other hand, when the inside of the room is looked at, the supply air volume tends to be insufficient with respect to the required air volume necessary to maintain a desired specified temperature. Therefore, when air is distributed and supplied to a large number of rooms by one air conditioner. Therefore, if the supply air volume of some rooms is increased, it is necessary to increase the damper opening in other rooms in order to secure its own supply air volume. Since it has to be done, it takes a long time to reach the specified temperature, and the change in the wind speed in the branch duct causes a large noise.

[0007]

The problem to be solved by the present invention is to set the rotation speed of the blower on the basis of the supply air volume when the damper is fully opened, and request the damper full-open signal and the supply air volume of each branch duct. The conventional technique of inputting the difference from the air volume into the rotation speed control device to control the rotation speed of the blower and operating the blower in a state where the air flow is insufficient, requires long wiring for signal transmission. In addition, the control system is complicated, and it takes a long time to reach the specified temperature in the room because the supplied air volume cannot be made to follow the required air volume sharply, which causes noise. is there.

[0008]

Air blown from an air conditioner including a blower and its rotation speed control device is branched from an air supply duct into a room through a plurality of branch ducts each having a terminal control unit including a damper. In the present invention, the means for solving the above-mentioned problems that the above-mentioned conventional techniques have in distributing and supplying are as follows.

That is, with all the dampers fully open, the wind speed at the location near the air conditioner of the air supply duct is measured in the range from the lowest to the highest rotation speed of the blower to obtain the maximum wind speed at each rotation speed. , Upper limit wind speed and lower limit wind speed in a wind speed region in which air maintains a predetermined static pressure at each rotation speed are set. Then, the rotation speed of the blower when the air is distributed and supplied to the room is kept as it is when the wind speed of the place near the air conditioner of the air supply duct is a value between the upper limit wind speed and the lower limit wind speed, and the maximum When the value is between the wind speed and the upper limit wind speed, it is increased, and when the value is smaller than the lower limit wind speed, it is decreased and the value is controlled to a value between the upper limit wind speed and the lower limit wind speed.

In summary, according to the present invention, the air flow rate of the centralized air conditioner is determined based on the air flow rate detected by the wind speed sensor installed in the air supply duct near the air conditioner. It controls the rotation speed of the blower so that the fluctuation of the supply air volume to the room of each branch duct branched from the air supply duct is detected by the wind speed sensor as the fluctuation of the wind speed to save the operating energy. At the same time, the operation is always performed at the minimum differential pressure to reduce noise.

As is well known, the centralized air conditioning equipment includes an air conditioner having a cooler, a heater, a blower and a rotation speed control device thereof, and air sent from the air conditioner is branched from an air supply duct. It consists of an air flow sensor, a damper, a damper opening / closing motor, a branch duct equipped with a terminal control unit that has an electronic control circuit, etc., and is required to instruct the terminal control unit to the desired specified temperature and maintain the supplied air volume at the specified temperature. The damper is opened / closed so that the required air flow rate is achieved.

In the present invention, a control unit for sending a predetermined blower operation signal to the rotation speed control device by installing a wind speed sensor at a location close to the air conditioner of the air supply duct of such a centralized air conditioner. Keep connected.

When the installation work of the centralized air conditioning equipment is completed, the dampers of all the branch ducts are forcibly fully opened to the minimum static pressure state, and the blower is gradually rotated from the minimum rotation speed to the maximum rotation speed. The speed is changed, and the amount of air blown by the blower at each rotation speed is replaced with the wind speed detected by the wind speed sensor and stored in the control unit. The control unit sends an operation signal in which the rotation speed of the blower is set so as to send a predetermined amount of air to the rotation speed control device, which is generally an inverter, and the wind speed sensor measures the wind speed and measures the wind speed. It has a function to detect changes in the blowing capacity.

When the wind speed at each rotation speed of the blower is measured as described above, a graph of these relationships can be created with the former as the horizontal axis and the latter as the vertical axis. FIG. 1 is an example thereof, and the wind speed is represented by a graph indicated by F1. Since this F1 is the wind speed detected in the minimum loss state in which all dampers are fully opened, that is, in the minimum static pressure state, it is the maximum wind speed at each rotation speed of the blower, and the blower capacity and the state of the air supply duct are The minimum differential pressure point is shown under the condition that it is constant.

Here, in order for the air volume adjustment by the damper of the terminal control unit of each branch duct to be performed stably and normally, it is necessary that the air flowing through the branch duct maintain a predetermined static pressure. In order to maintain the pressure, it is necessary for the blower to have a blowing capacity that adds the blowing loss of the branch duct.

That is, F1 shows the relationship between the rotation speed of the blower and the wind speed in the minimum loss state. In most cases, all the dampers are not fully opened during actual operation, so the loss is calculated. The predetermined required air volume cannot be supplied unless the supplementary rotation speed is added.

When the damper of the branch duct is opened / closed according to the specified temperature of the room, and the blower is operated at the rotational speed a with reference to FIG. 1, the value F1 of F1 at that time is F.
There is a wind speed when the blower is operated while maintaining a predetermined static pressure in a wind speed region lower than a1. Letting Fa2 be the upper limit wind speed and Fa3 be the lower limit wind speed in the wind speed region in which the predetermined static pressure is maintained, the wind speed region in which the predetermined static pressure is maintained at each rotation speed passes through Fa2 and Fa3 at the rotation speed a and is parallel to F1. , F3. In other words, F2 is set to the minimum wind speed that compensates for the loss that occurs because all dampers are not fully open, and F3 is set to the wind speed that does not cause hunting in control.

It is assumed that when the dampers of the respective branch ducts are each set to a predetermined opening and air is distributed and supplied into the room, the rotation speed of the blower is b and the detected value of the wind speed sensor at that time is Fb. .. This wind speed Fb is compared with the values of the rotational speeds b of F1, F2, and F3 stored in the control unit, and as shown in FIG. 1, the maximum wind speed F1 and the upper limit wind speed F2.
Between the upper limit wind speed F2 and the lower limit wind speed F3, which is within the range of the predetermined static pressure while maintaining the wind speed b. The rotational speed is increased to the internal rotational speed bs.

When the rotational speed of the blower is c and the detected value Fc of the wind speed sensor at that time is smaller than the lower limit wind speed F3, the static pressure is unnecessarily high and operating energy is wasted. Judge, maintain wind speed Fc and maintain upper limit wind speed F
The rotation speed is reduced to the rotation speed cs in the region between 2 and the lower limit wind speed F3.

The minimum air flow rate is set for each terminal control unit, and the minimum wind speed is obtained from the sum of the minimum air flow rate and the cross-sectional area of the air supply duct, and the detected value of the wind speed sensor becomes the minimum wind speed during actual operation. If so, the above control is stopped and the blower is operated at a rotation speed that maintains the lowest wind speed.

Further, when the rotation speed of the blower is d and the detected value Fd of the wind speed sensor at that time is in the region between the upper limit wind speed F2 and the lower limit wind speed F3, the predetermined static pressure is maintained. Then, the operation is performed while maintaining the rotation speed d.

When the blower is operated at a rotational speed d for maintaining a predetermined static pressure, if the damper opening of a certain branch duct is increased, the blower loss in that branch duct will decrease and the wind speed will rise. It becomes Fd1 of. At this time, the rotational speed is increased to d1 and the operation is controlled in a region where the predetermined static pressure is maintained. It is also assumed that when the damper opening of a certain branch duct is reduced, the air loss in that branch duct increases and the wind speed decreases to Fd2. At this time, the rotation speed is reduced to d2 and the operation is controlled to operate at a predetermined static pressure. In these cases, when the increase or decrease in the wind speed is large, the above operation is repeated to obtain the rotation speed that gives a predetermined air flow rate in a predetermined static pressure region.

In actual control, when a constant control cycle is set and the rotation speed is changed, the average value of wind speeds within a predetermined time width within the control cycle is calculated to determine whether or not the next rotation speed needs to be changed. In addition, the rotation speed change width is determined. Further, when the average value is equal to or more than the above F1 and is less than a certain value than the above F3,
The increase or decrease of the rotation speed is accelerated to reach the predetermined static pressure region in a short time.

[0024]

The blowout wind speed of the blower forming the predetermined static pressure region is obtained for each rotational speed, and when the wind speed fluctuates due to the change in the blowing loss of the terminal control unit of the branch duct,
The wind speed, that is, the rotation speed within a predetermined static pressure region for maintaining the air flow rate is changed. As a result, the rotation speed of the air flow rate is controlled so that the air flow rate corresponds to the load amount, and energy saving operation is always performed by the minimum differential pressure.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the centralized air conditioning equipment to which the present invention is applied will be described with reference to FIG. 2. An air filter 2, a cooler 3, a humidifier 4, a heater 5, a blower 6, a rotation speed controller 7 and Air conditioner 1 with electronic control unit 8
In the above, the outside air, the return air, or the mixed air thereof is adjusted to the air for cooling or heating, and is blown at the ends of the plurality of branch ducts 12 which are pressurized by the blower 6 and pass through the air supply duct 11. It is adapted to be distributed and supplied into the room through the outlet 13.

A wind speed sensor 9 is installed at a portion of the air supply duct 11 near the blower 6, and the detected wind speed is input to the control unit 8. The control unit 8 compares the stored maximum wind speed, upper limit wind speed, and lower limit wind speed with the input wind speed to operate the blower 6 at a rotation speed within a predetermined static pressure region that maintains a predetermined air flow rate. An operation signal is sent to the rotation speed control device 7.

Each branch duct 12 has a terminal control unit 1
5 are installed respectively. This unit 15 includes an air flow sensor 16 and a damper 1 inserted in a branch duct 12.
7, an electronic control circuit 18 installed outside the branch duct 12, a motor drive circuit 19, a damper opening / closing motor 20,
A room temperature sensor 21 for detecting the room temperature and a room temperature controller 22 for setting the room temperature at a desired designated temperature.

When the occupant of the room operates the room temperature controller 22 to specify the desired room temperature, the specified temperature signal and the detected temperature signal corresponding to the actual room temperature detected by the room temperature sensor 21 are electronically transmitted. Expression control circuit 18 is compared,
The required air volume is calculated according to the difference between them. On the other hand, the supply air volume detected by the air volume sensor 16 is sent to the electronic control circuit 18 and compared with the required air volume, and an opening / closing signal corresponding to the difference is sent to the motor drive circuit 19 to specify the operation direction and the operation amount. A drive signal is generated, and the damper open / close motor 20 drives the damper 17 to open / close by the drive signal to supply the required amount of air to the room.

The change in the amount of air blown due to the opening / closing of the damper 17 is detected by the wind speed sensor 9 of the air supply duct 11, and the rotational speed of the blower 6 is controlled by the above-mentioned means.

[0030]

According to the present invention, the information of the terminal control unit is detected by the change in the wind speed of the blower without being transmitted to the air conditioner by wiring, so that it is within the wind speed range in which the predetermined static pressure set in advance is maintained. Since it controls the rotation speed of the blower, it can always operate at the minimum differential pressure with a simple configuration to make the supplied air volume sharply follow the required air volume and reach the specified temperature in the room in a short time, and Noise is reduced because the change in wind speed in the branch duct is the minimum required amount.

[Brief description of drawings]

FIG. 1 is a relationship diagram between a rotation speed and a wind speed for explaining an example of a control method according to the present invention.

FIG. 2 is a schematic view showing an example of a centralized air conditioning equipment to which the present invention is applied.

[Explanation of symbols]

1 air conditioner, 6 blower, 7 rotation speed control device,
8 control unit, 9 wind speed sensor, 11 air supply duct,
12 branch ducts, 15 terminal control units, 17 dampers,

Claims (1)

[Claims] 1. When the air sent from an air conditioner including a blower and its rotation speed control device is branched from an air supply duct and distributed and supplied into a room through a plurality of branch ducts each having a terminal control unit including a damper. Determining the maximum wind speed at each rotation speed by measuring the wind speed of a portion of the air supply duct that is close to the air conditioner in a state where the rotation speed of the blower is minimum to maximum with all the dampers fully opened. An upper limit wind speed and a lower limit wind speed in a wind speed region in which air maintains a predetermined static pressure at each rotation speed are set in advance; the rotation speed of the blower when the air is distributed and supplied to a room is set to the rotation speed of the air supply duct. When the wind speed of the part approaching the air conditioner is a value between the upper limit wind speed and the lower limit wind speed, it remains as it is, and when it is a value between the maximum wind speed and the upper limit wind speed, it rises. When the value is smaller than the lower limit wind speed, the value is decreased to control the value to be a value between the upper limit wind speed and the lower limit wind speed;