Ventilation aeraulique distribution d'airVentilation aeraulique distribution d'air

aeraulic load losses in ventilation systems are irreversible loss of energy because the loss is converted into heat or noise :

Suction ventilation calculation software Mecaflux pro3D:

Tutorial: create a suction ventilation systems
Modelize the suction AERAULIC ventilation systems networks.
aeraulic air ventilation

Ventilation renews and cleanses the indoor air and provides fresh air necessary for well being of the occupants.

The nine principles of ventilation(INRS)

• Wrapping at maximum area pollutants
• Capter au plus près de la zone d'émission
• Collecting at closer to the emission zone
• Using the natural movements of pollutants
• Induce sufficient air velocity
• Uniformly distributing the air speed at the zone
collection
• Compensate for air outlets with corresponding air inflow
• Avoid the air currents
• Reject the polluted air outside of the areas of fresh air inlet

regulation based on two principles: :
• Aeration should be general and permanent ;
• It must scan the entire housing with installed air inlets in the main rooms and outlets placed in service rooms.


  extracts Flow rates expressed in m3/h
Number main rooms kitchen Bathroom Other bathroom single WC WC multiple
1 75 15 15 15 15
2 90 15 15 15 15
3 105 30 15 15 15
4 120 30 15 30 15
5 et plus 135 30 15 30 15


When the ventilation is ensured by a mechanical device that automatically module housing air renewal, so that the rate of indoor air pollution do not constitute any health hazard, and the condensation can be avoided, except transiently, the rates defined in the table above may be reduced.

• If it is a CMV (controlled mechanical ventilation) Single flow the minimum flows to respect are :

Nb main rooms 1 2 3 4 5 6 7
Total minimum flow in m3/h 35 60 75 90 105 120 135
Minimum flow in kitchen m3/h 20 30 45 45 45 45 45

•And if it is a humidity controlled ventilation, minimum ventilation rates are further reduced :
Nb main rooms 1 2 3 4 5 6 7
Total minimum flow in m3/h 10 10 15 20 25 30 35
 

Labour Code

Office premises without physical work
25 m3 per hour
Local restoration, sale, assembly
30 m3 per hour
Workshops with local light physical work
45 m3 per hour
Other workshops and local
60 m3 per hour

 

The hourly rate of brewing - or HRB - is the number of times the air is renewed in a room for a period of one hour.. Unlike the hourly turnover rates, the air flow in the room is not new and can come from an air intake followed by filtration.

For example, with a system of supply and return air with a flow rate of 30 m³ per hour, the HRB will be 3 for a room of 10 m³..

hourly turnover rates – HTR – is the number of times the air is changed in a room for a period of one hour. Unlike the hourly rate of brewing, the air blown into the room is new.

For example, with a system of supply and extract with a flow of 30 cubic meters per hour, HTR will be 3 for a room of 10 m³.

Mechanical ventilation is the cause of two types of energy expenditure:

  1. Energy expenditure of the fan

    Expenses related to the fan is calculated by multiplying the engine power (in kW) by the annual operating time (8760 hours if the operation is continuous). This corresponds to the major losses in the air ducts and minor head loss of the system and fan efficiency

  2. The cost of heat (in winter) corresponding to the need to heat the air renewed

    Expenses related to heating (E Wh / year) can be calculated as follows:


Exemple : Building with a living area, heated of 2 380 m² (ceiling height 2.50m). Consumption of heating : 563 000 kWh. The CMV (controlled mechanical ventilation) is a power of 1150 W and renews the air up to 1 vol/h.
E = 0.34 * 5 950 * 2 321 * 24 = 112 689 190 Wh =>112 689 kWh
This consumption represents about 20% of annual heating consumption of condominiums.

 

 

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