Airflow Systems IAQ50 - page 17

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Using CO2:
%OA= (CR–CS) / (CR–CO) x 100%
where %OA = Percentage of outside
air
C
R = Concentration CO2 of
return air
C
S = Concentration CO2 of
supply air
C
O = Concentration CO2 of
outside air
Using Temperature:
%OA= (TR-TS) / (TR-TO) x 100%
where %OA = Percentage of outside
air
T
R = Temperature of return
air
T
S = Temperature of supply
air
T
O = Temperature of outside
air