Application Guide

63-7062 32
Constant Air Volume with Air Quality Compensation (See Fig. 37)
M
M
M
s
T
Honeywell
EMC
Controller
T
M
CO2
or AQ
-
+
TS
DP
DP
T
One Inverter could be used, but two is a better option.
RST
PG
MONPARREF BTNS
RUNREADYFAULT
Honeywe
l
l
RST
PG
MONPARREFBTNS
RUNREADYFAULT
Honeywel
l
Fig. 37 Application Diagram.
Application Description
The application is as the previous standard CAV application, but with the addition of an air quality (AQ) or CO
2
detector fitted in
either the extract duct or within the space. The air quality detector will control the dampers and the VFD in sequence.
As an example the temperature control could be satisfied with minimum heat output and supply/extract fan running at slow
speed. With a large density of people in the space the air quality could be low (cigarette smoke, stale air and CO
2
), while
maintaining temperature control conditions.
The AQ detector could compensate for this by opening the fresh air dampers and increasing the fan speed in sequence. The
control circuit will be modified to include two highest of two signal selector relays on the inputs to the VFD and the fresh air
dampers.
Possible Usage
— Airport arrival and departure lounges.
— Theaters.
— Cinema.
— Lecture halls.
— Exhibition halls.
Benefits
— Reduced running costs.
— Maintenance savings due to reduced mechanical stress.
— Improved indoor air quality.