12
5 - AERAULIC CONNECTIONS
5.1 GENERAL
Proper execution and sizing of air connections are essential
for ensuring correct operation of the unit and an acceptable
level of silence in the room.
When designing and creating ducts, consider PRESSURE
DROPS, FLOW RATE and AIR SPEED which need to be
compatible with the characteristics of the unit.
Special consideration needs to be made for pressure drops
that are greater than the unit's static pressure, which would
lead to a reduction in flow rate resulting in unit shutdown.
• the weight of the ducts must not be supported by the
connection flanges
• place anti-vibration joints between the ducts and the unit
• the connection to the flanges and between the various
sections of the ducts must ensure an airtight seal, preven-
ting leakage in delivery and return which would compromi-
se overall system efficiency.
• limit pressure drops by optimizing the path, the type and
number of curves and the branches
• use curves with a wide radius. Consider whether it might
be useful to equip them with deflectors (especially if the air
speed is high or if curves are tight )
• The inner surface of the duct must be smooth and washa-
ble. It must not contaminate the air.
• Thermally insulate the ducts and the flanges so as to pre-
vent loss of energy and condensation build-up.
GRILLES OUTLETS DIFFUSERS
Proper distribution of air in the room is essential for ensuring
comfort levels.
In the selection and positioning of grilles, outlets and diffusers,
the following are to be avoided:
• excessive air speed
• formation of stagnant zones and layering
• entry of cold air into the room
• formation of localized currents (due to uneven air
distribution)
• excessive variations in ambient temperature in the
vertical and horizontal planes
• short circuiting of delivery air towards return air
5.2 FEATURES FOR DUCTS FOR TREATED AIR
For purposes of comfort, the following things need to be consi-
dered:
• air diffusers must be selected by checking the sound
power generated at nominal flow rate conditions
• the disconnections to the diffusers are to be made
using flexible elements
• the return grilles must be amply sized
APPLICATIONS AT HIGH DEGREE OF SILENCE
For applications that require a high degree of silence in the
system:
• In delivery and return, provide septum silencers, pre-
ferably inserted in sections of ducts located outside
the building. The septums must ensure the required
dampening with minimum pressure drops (ONLY
OUTDOOR UNITS – do not print note).
• Equip all curves with deflectors.
To Next Page
Loading...
Need help?
General
