GHM DeltaOHM HD37AB1347, Руководство по эксплуатации

Страница: 30 / 64

HD37AB1347
- 30 -
V3.0
Where:
X
R
= CO
2
concentration or temperature T in return air
X
S
= CO
2
concentration or temperature T in inlet air
X
O
= CO
2
concentration or temperature T in outdoor air
_____________________________________________________________________________
Example
Let's suppose you have performed the following CO
2
measurement in a working
environment:
CO
2
in outdoor air = X
O
= 400 ppm
CO
2
in inlet air = X
S
= 660 ppm
CO
2
in return air = X
R
= 850 ppm
% 2 . 42 % 100
) 450 (
) 190 (
% 100
) 400 850 (
) 660 850 (
% 100
) (
) (
%
= ⋅ = ⋅
−
−
= ⋅
−
−
=
O R
S R
X X
X X
OA
The same equation can be used if you know the temperatures T. Let's suppose the
measurement is performed in winter:
T in outdoor air = X
O
= 0 °C
T in inlet air (before conditioning) = X
S
= 10 °C
T in return air = X
R
= 23 °C
% 5 . 56 % 100
) 23 (
) 13 (
% 100
) 0 23 (
) 10 23 (
% 100
) (
) (
% = ⋅ = ⋅
−
−
= ⋅
−
−
=
O R
S R
X X
X X
OA
________________________________________________________________________________
The calculation of the percentage of outdoor air is not meaningful, if it is not
correlated to the air flow in the environment.
Let's suppose, for example, that the environment is an office. The ASHRAE 62.1 norm
recommends a ventilation rate of about 8.5 L/s×person.
Let's suppose that you have the following measurements:
Air Flow = 500 L/s
Number of occupants = 10 people
% Outdoor Air = 17%OA
person s L
people
OA s L
× =
⋅
/ 5 . 8
10
% 17 / 500
In this case, the ASHRAE 62.1 norm recommendation of a ventilation rate of about
8.5 L/s×person was met.
If, in the same environment, you have an air flow =
100 L/s , you need a %OA = 85%
to meet the ASHRAE 62.1 norm.
person s L
people
OA s L
× =
⋅
/ 5 . 8
10
% 85 / 100
In this example you can see that only correlating the %OA value with the air flow
value you can check if the ventilation rate meets the ASHRAE 62.1 norm.