JPH0229533A - Control method for outdoor air intake in vav control system - Google Patents

Abstract

PURPOSE:To allow making up an absolute shortage of outdoor air in rooms to be controlled by controlling the intake outdoor air volume with respect to the recirculating air volume to an air conditioner according to the delivery air flow rate. CONSTITUTION:The opening of an outdoor air regulating damper 12 is gradually reduced from MAX with an increase in the rotation speed of a fan F, and kept at MIN after the rotation speed reaches the specified one. That is, as the room temperature in rooms 6-1-6-n to be controlled becomes closer to the set point, the opening of the dampers in VAV units 8-1-8-n are more reduced causing a more reduction in the delivery air flow rate of an air conditioner 1. Consequently, as the opening of the outdoor regulating damper 12 becomes larger resulting in more increase in the outdoor air intake, the ratio of the outdoor air content in the rooms 6-1-6-n to be controlled becomes higher so that an absolute shortage of outdoor air in the rooms 6-1-6-n to be controlled is made up.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a V A V system comprising a return air means for returning a part of exhaust gas from a controlled room to an air conditioner together with outside air.
t+I] This relates to an outside air intake control method for a control system.

[Conventional technology]

Conventionally, in large-scale buildings, when supply air is supplied from an air conditioner to each part via an air supply duct, a variable supply air amount adjustment unit is used for each supply air outlet of each part to be air-conditioned (controlled room). (hereinafter referred to as a VAV unit), and this VA
The damper opening degree of the V unit is controlled according to the room temperature of the controlled room, and the supply air blowout amount for each controlled room is adjusted.
The amount of air supplied to the air conditioner is controlled according to the opening degree of the damper of the V unit (Japanese Patent Application No. 1983-1999 by the present applicant).
227933).

Generally, in such a V A V @ control system, a part of the exhaust gas from the controlled room is returned to the air conditioner as return air, and outside air is used at a predetermined ratio (a certain ratio) to the return air returned to the air conditioner. ).

[Problem to be solved by the invention]

However, in such a conventional VAV control system, the closer the room temperature of the controlled room is to the set temperature, the more the damper opening of the VAV unit is reduced, and the amount of air supplied to the air conditioner is accordingly reduced. Become something. That is,
The amount of supply air blown into the controlled room decreases, and as a result, the absolute amount of outside air in the controlled room is insufficient, resulting in CO! There was a risk that the concentration would increase and the environment would deteriorate.

[Means to solve the problem]

The present invention has been made to solve these problems, and it controls the amount of outside air taken in for the return air returned to the air conditioner (outside air intake amount) according to the amount of air blown out from the air conditioner. This is how it was done.

[Effect]

Therefore, according to the present invention, if the amount of outside air intake is controlled to be increased in response to a decrease in the amount of air supplied to the controlled room, the ratio of the outside air contained in the amount of air to the controlled room is increased in response to a decrease in the amount of air blown into the controlled room. , it becomes possible to compensate for the lack of absolute amount of outside air in the controlled room.

〔Example〕

Hereinafter, the outside air intake control method in the VAV control system according to the present invention will be explained in detail.

FIG. 2 is an instrumentation diagram of a VAV control system to which an embodiment of this outside air intake control method is applied.

In the figure, 1 is an air conditioner, which includes a cooling coil CC to which cold water CW is supplied via an electric valve 2, a heating coil HC to which hot water HW is supplied via an electric valve 3, and a variable rotation speed (inverter control). It is composed of a fan F. Air conditioner 1. The operation of the electric valve 2 and the electric valve 3 is controlled by a control device 4, and the operation of the electric valve 2 and the electric valve 3 is controlled by a control device 4.
The supply air (blown supply air) blown out from the fan F is supplied to the controlled rooms 6-1 to 6-7 via the air supply duct 5.

The controlled rooms 6-1 to 6-7 are each equipped with temperature sensors T-1 to T-, which detect the room temperature, and the detection power of the temperature sensors T-1 to T- is Local regulator 1-1
~7-. 1, and this regulator 7-1
~7-7 commands VAV units (8-t~8-7) branched from the air supply duct 5 and inserted into each outlet in response to the detected power of the temperature sensors T-1~T-. Based on this command, the damper opening degrees of the VAV units 8-1 to 8-7 are controlled according to the room temperature. On the other hand, the regulators 7-, ~7-1l are connected to the control device 4 via transmission lines, and data indicating the damper opening degrees or air volume of the VAV units 8-1 to 8-9 is provided to the control device 4. Based on these data, the control device 4 performs control calculations, controls the inverter of the fan F, adjusts its rotation speed, and varies the amount of air supplied to the supply air duct 5. ing.

Controlled room 6-3 via VAV units 8-, ~8-7
The supply air (supply air blowout) blown out to ~6-7 contributes to the air conditioning control in the controlled rooms 6- and ~6-7, and then is discharged via the return air duct 9 and the exhaust adjustment damper 10. However, a part of the air is returned to the air conditioner 1 as return air via the return air adjustment damper 11. Then, outside air is introduced into the return air returned to the air conditioner 1 via an outside air adjustment damper 12. The opening degree of this outside air adjustment damper 12 is controlled in accordance with the rotation speed of the fan F based on a command from the control device 4.

FIG. 1 is a characteristic diagram showing the opening degree of the damper 12 for adjusting outside air, which is controlled according to the rotation speed of the fan F. That is, as the rotation speed of the fan F increases, the opening degree of the outside air adjustment damper 12 is gradually decreased from the MAX value, and after reaching the predetermined rotation speed N1, the opening degree is reduced to the MIN value (30%). to be maintained. That is, the closer the room temperature of the controlled rooms 6-t to 6-7 is to the set temperature, the more the vAV units 8-t to 8-
The opening degree of the damper 7 is reduced, and accordingly the rotation speed of the fan F is controlled to a low speed, and the amount of air supplied to the air conditioner 1 is reduced. If the amount of air supplied to the controlled chambers 6-, 6-n is reduced, the degree of opening of the damper 12 for adjusting outside air becomes larger and the amount of outside air taken in increases. The proportion of outside air contained in the air decreases, and as a result, the controlled rooms 6-1 to 6-
This will compensate for the lack of absolute amount of outside air in 7. That is, by increasing the absolute amount of outside air in the controlled rooms 6-I to 6-7, it is possible to suppress the increase in the CO□ concentration,
It will be possible to improve the deterioration of the environment.

In addition, as shown in FIG. 3, the opening degree control of the outside air adjustment damper 12 is actually performed using the rotation speed of the fan F in the air conditioner 1 as one factor, and the concentration of CO and the outside air cooling P.
Factors such as ID (enthalpy calculation) and minimum amount of outside air are taken into consideration, and control is performed using the maximum opening value determined by these factors.

Furthermore, in this embodiment, the amount of air supplied from the air conditioner 1 is known based on the rotation speed of the fan F, but an air volume sensor and a pressure detector are provided in the air supply duct 5 to directly measure the amount of air supplied. There are various other ways to know the amount of air supplied to the air conditioner 1. That is, it is not limited to the number of rotations of the fan F.

〔Effect of the invention〕

As explained above, according to the outside air intake control method in the VAV control system according to the present invention, 1. Since the amount of outside air intake relative to the return air is controlled according to the amount of air supplied by the air conditioner, if the amount of outside air intake is increased in response to a decrease in the amount of air supplied, the controlled It becomes possible to compensate for the shortage of the absolute amount of outside air in the controlled room by increasing the proportion of outside air contained in the reduced amount of supplied air blown into the room, and it becomes possible to improve the deterioration of the environment.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the opening degree of the damper for adjusting outside air according to the fan rotation speed, and FIG. FIG. 3 is a diagram showing the relationship between the opening degree control of the outside air regulating damper and other factors. 1... Air conditioner, F... Fan, 4... Control device,
5... Air supply duct, 6-3 to 6-7... Controlled room, 7
-1 to 7-7...Adjuster, 8-, ~8-7...VA
V unit, 9...Return air duct, 11...Return air Q damper, 12...Outside air adjustment damper.

Claims (1)

[Claims] an air conditioner having a function of varying the amount of air supplied; a variable air supply amount adjusting means that receives air supplied from the air conditioner and controls the amount of air blown to the controlled room according to the load condition of the controlled room; A control means for controlling the supply air amount of the air conditioner according to the control status of the supply air blowing amount by the variable supply air amount adjusting means, and a part of the exhaust air from the controlled room is combined with outside air as return air. and a return air means for returning air to the air conditioner, characterized in that the intake amount of the outside air with respect to the return air is controlled according to the blowout supply air amount. outside air intake control method.