Delta OHM HD37AB1347, Руководство пользователя

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4.6 V
ENTILATION
R
ATE
To calculate the Ventilation Rate you need the following parameters:
•
Calculation of the percentage of outdoor air inlet in the environment (% Outdoor Air)
•
Calculation of the air flow circulating in the environment being examined;
•
Number of people usually present in the environment being examined.
4.6.1 Definition of % Outdoor Air
The percentage of air inlet in the environment (% Outdoor Air) can be calculated measuring the
CO
2
Carbon Dioxide or the Temperature T.
Generally, you should measure the CO
2
Carbon Dioxide when there is a lot of people in the
environment being examined. Instead, you should use the temperature T when the indoor/outdoor
temperature difference is very large.
To calculate the outdoor air percentage you need to detect CO
2
concentration or temperature T in
three different points: outdoor air, inlet air and return air, using the following equation:
% 100
) (
) (
%
⋅
−
−
=
O R
S R
X X
X X
OA
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
________________________________________________________________________________