Calculation Of Duct Pressure Loss - Daikin VAM-FA8VE Technical Data Manual

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11.3 Calculation of Duct Pressure Loss

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• HRV • VKM-GA(M)V1
Required air flow based on tobacco smoking and odor
6-class odor level presentation (this classification is linked with an approximate, intuitive
estimation of gas concentration)
Odor intensity
0 Odorless
1 Manages to detect the presence of odor (threshold concentration)
2 Manages to detect what is producing the odor (threshold concentration)
3 Easily detects the odor
4 Strong odor
5 Very strong odor
For example, to keep the odor level not greater than 2, the contamination concentration (tobacco
combustion amount (mg)/ventilation amount (m
the odor level not greater than 1, the contamination concentration should be reduced to 17.7 mg/m
smaller. To calculate required air flow based on smoking concentration, use the following equation.
Tobacco combustion (mg/h · person)
Q =
Allowable contamination (mg/m
<Example>
Assumptions : Combustion per cigarette
Combustion rate
Number of cigarettes per person
Odor intensity level
1,000 × 0.7 × 4
Q = = 79.3m
35.3
Therefore, under the conditions given above, in the case of cleaning air using ventilation only, about 80 m
h/person of air flow is required. By using air cleaners and/or deodorizers in conjunction with the ventilation
system, its capacity can be reduced significantly.
Required air flow depending on the degree of smoking (estimated)
Degree of smoking Locations
Dealer office, newspaper
Very high
editing room, meeting room
Bar, office, hotel
High
(guest room)
Medium (to high) Restaurant, office
Sales room in a bank,
Low (sometimes)
office, shop
Some types of ventilating fans, including those (pressure types) installed in a cooking range hood, are
installed in a ducted system. The air flow depends on the pressure losses determined according to the
length of the ducted system and the number of bends, and other accessories contained in the system. Air
flow calculations should consider these pressure drops to estimate the air flow as accurately as possible.
• HRV • Heat Reclaim Ventilation
Description
3
)) should be reduced to 35.3 mg/m
(m 3 /h)
3 )
1,000 mg
70%
4/h · person
2 (=35.5 mg/m
3
/h · person
Required air flow (m
minimum to recommended value
51~85
42~51
20~26
13~17
3
or smaller. To keep
3 )
3
/h/person), Smoking amount (number
of cigarettes/hour/person)
3~5.1
(1.5~2.5)
2.5~3
(1.3~1.5)
1.2~1.6
(0.6~0.8)
0.8~1.0
(0.4~0.5)
3
or
3
/