Perforated Multistream Diffuser

Smartemp PMW-AD

High induction, side blow diffuser with manually adjustable multi-stream discharge pattern, for draught-free air supply from walls or bulkheads.

The SMARTEMP Perforated Multistream Diffuser, type PMW-AD, is a side-wall diffuser that provides high levels of draught-free thermal comfort in such spaces as hotel rooms, apartments, restaurants and commercial offices. The design is both aesthetically pleasing and technically advanced. Unlike standard side-blow air grilles, which produce broad, low momentum air bundles that mix poorly with room air, the PMW-AD discharges a multitude of individual, high momentum air streams, each one of which is highly inductive. These produce largely uniform temperature distribution with low draught-risk throughout the occupancy space. Thermal comfort levels are high even when airflow rates are high.


Mixed flow discharge
High induction discharge intensely mixes supply air with room air. Strong supply air dilution with rapid discharge velocity decay produces draught-free, high momentum supply air motion of uniform temperature distribution over short or long throws.  Ideal for enhanced thermal comfort (ADPI ≥ 90%).

Return air
Also suitable for use as a return air inlet. Wall location: Air supply from sidewall, bulkhead or side of duct.

Low temperature supply
May be used for low temperature (cold air) supply systems (Tsupply ≈ 10 °C), where ∆Tsupply-room ≥ -12 K.

VAV dependent throw
VAV turndown to approximately 50% @ ∆Tsupply-room ≈ -12 K, with throw dependent upon airflow rate.

Adjustable direction
Multistream jets are individually adjustable, providing air pattern direction, spread and throw adjustment for up/down, left/right, short, medium or long throw.

Manual adjustment
Manual air pattern adjustment through diffuser face by means of an Allen key avoids inadvertent changes to discharge pattern setting (eg by cleaners).

Rectangular face shape
Height from 134 to 251 mm. Standard width options: 612, 950 and 1490 mm. Bespoke widths: 207 to 1490 mm.

Perforated face pattern
Discharge through perforated metal face with 60° stagger.

Plastic face
Black recessed adjustable discharge elements.

Metal face
Perforated metal finish in extruded aluminium frame, painted to colour of choice.

Airflow rate range

  • 30 – 500 L/s (108 – 1800 m³/h)


  • 1.3 – 17 m

Nominal length

  • 0.6 m
  • 0.95 m
  • 1.5 m
  • Bespoke lengths ≤ 1.5 m available

Face height

  • 134 mm
  • 173 mm
  • 212 mm
  • 251 mm

Discharge height

  • 2.5 – 4 m


  • Highly inductive multi-stream discharge for draught-free comfort.
  • Multi-stream discharge direction manually adjustable via Allen key through diffuser face.
  • Allen key adjustment prevents inadvertent discharge direction adjustment (eg by cleaners).
  • Black plastic discharge elements (ABS, V0 fire rated) located behind the perforated discharge face break the airflow into a multitude of highly inductive individual air streams of differing discharge direction.
  • Adjustable air streams have four different discharge angles, with the outer angles flatter than inner ones, and each may be rotated to one of six discharge directions, ensuring highly inductive, broad dispersion of the supply air flow for draught-free air supply.
  • Perforated discharge face and frame of metal, painted to colour of choice.


International patent applications and granted patents are listed at


The SMARTEMP Perforated Multistream Diffuser, type PMW-AD, is a high induction sidewall diffuser. Multi-stream airflow is discharged by a multitude jet elements of differing discharge direction, each manually adjustable to alter the diffuser air pattern.

High levels of draught-free thermal comfort are provided by the multitude of highly inductive individual air streams discharged from its perforated face.  It is well suited to high comfort applications such as hotel rooms, apartments, restaurants, aged care and offices.

The patent pending design discharges a multitude of individual, high momentum free air streams. The discrete discharge direction of each air stream maximises induction. High induction intensely dilutes the supply air with room air to produce rapid discharge velocity decay combined with a strong increase in the supply air stream mass flow rate.

The advantages of high induction discharge include improved air temperature distribution with low draught-risk, and make the diffuser suitable for both long throws (due to the high momentum of the air stream ) as well as short throws (due to the low air stream velocity).

The SMARTEMP PMW-AD diffuser is suitable for substantially CAV systems (turndown to no less than 50%) including low temperature supply air systems in which supply air temperature is ≥ 10 ⁰C and ΔTsupply-room ≥ -15 K. Enhanced levels of draught-free comfort are achieved, with air diffusion performance index values (ADPI) typically in excess of 90%.

The SMARTEMP PMW-AD Perforated Multistream Diffuser is available in selected markets as the LTG Freistrahl-Wanddurchlass ILF.


Airflow Direction

Face Material


Face Pattern

Face Shape


Supply Temperature


Product Type



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