Passive thermal displacement ventilation
Displacement ventilation uses
stratification to its advantage. Cool air is introduced at low
level, and warm air is allowed to stratify at the ceiling. For this
reason, displacement ventilation is usually employed in spaces
above 3m high.
As the air is supplied very close to the occupants, temperatures
are kept higher to avoid occupants near the diffusers getting cold.
These larger air volumes can bring their own problems though. The
air must be introduced very slowly into the space to minimise both
noise and draft. If using a metal system, this means making
thousands of small perforation in steel plate, this is a very
expensive process, and explains why conventional displacement
solutions can be expensive. Textile diffusers deliver air through
their entire surface for ultimate low velocity.
All low impulse systems act as displacement diffusers and can
achieve the same effect when fitted at high level, as the supply
air does not mix with the room air.
Vertical textile displacement diffusers are often supplied in 2-3m
lengths, these are clamped to a steel supply duct and hang down
freely. The diffusers are impact resistant and can be temporarily
removed if access is required.
If heating is required, or a larger area needs to be covered by a
single diffuser, nozzles can be added to the surface of the duct to
Laboratory test data is available to show velocity at varying
heights at a number of distances from the duct.
This solution has been accepted by many blue-chip companies such
as Rolls Royce, Vodafone, Pepsico and Nestle.
contact us for more information about displacement