High capacity multi-swirl diffuser (2, 3 or 4 x DN250) with high induction, fixed horizontal discharge pattern from swirl vanes flush with diffuser face, suitable for nominally 300 mm wide ceiling grids. Unique helical twist vane design provides high airflow capacity, and allows low-temperature VAV (T_supply ≥ 5 °C) with turndown to 25%.  Suitable for installation in a closed ceiling.

	Location – above: Air supply from above the space, integrated flush with a closed ceiling or freely suspended.
	Mixed flow discharge: High induction swirl 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 with 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.
	Low temperature supply: May be used for low temperature (cold air) supply systems (Tsupply ≥ 5°C), where ∆Tsupply-room ≥ -16 K.
	VAV dependent throw: Throw dependent upon airflow rate. Minimum airflow dependent upon ∆Tsupply-room (eg turndown to 25-28%, neck reducer dependent, and down to ≈1 L/s/m2 @ ∆Tsupply-room ≈ -16 K).
	Fixed direction: 360° radial pattern (4-way blow), horizontal discharge pattern.
	Rectangular face shape: Lay-in tile, suitable for standard ceiling grids 300 mm wide, 600 mm, 900 mm or 1200 mm long.
	Radial face pattern: flush-face, offset-radial vane pattern matches SMARTEMP Fixed Helical Swirl Diffuser (HSC-FD), Adjustable Helical Swirl Diffuser (HSC-AD) and Helical Vari-Swirl Diffuser (HSC-VS).
	Metal Face: Powder coated metal finish.

Options

	Smudge minimiser: CleanScreen™ air supply through optional perforated hub washes diffuser face with clean supply air, minimising diffuser face soiling due to air borne contaminants from the room. Patents pending.
	Sweat inhibitor: CleanScreen™ (patents pending) air supply through optional perforated hub washes diffuser face with dehumidified supply air, eliminating diffuser face condensation due to humid room air.
	Blanking segments: Provide 2-way or 3-way discharge patterns. May be combined with neck reducers.
	Plenums: Side-entry foam connection boxes with threaded rod or magnetic edge strip fastenings.

SMARTEMP Multi-Swirl Diffuser MSC-FD

Airflow rate

• 60 – 190 L/s (216 – 684 m³/h)

Supply temperature

• ≥ 5°C

Nominal neck sizes

• DN250

Discharge height

• 2.4 – 4.5 m

Features

• Nominally 300 mm wide.
• Nominally 600 mm, 900 mm or 1200 mm long.
• 2, 3 or 4 swirl diffusers size DN250.
• Flush face with 20 off-set radial vanes per swirl diffuser.
• High airflow capacity.
• Fixed horizontal discharge pattern.
• Ceiling mounted.
• Suitable for CAV or VAV with large range (eg turndown to 25%-28% @ T_supply-room = -16 K).
• Suitable for low temperature supply air (≥ 5°C and ∆T_supply-room ≥ -16 K).
• Swirl vanes with helical twist (flatter peripheral vane angle) extend VAV operating range – patents pending.
• Swirl vanes with cambered leading edges reduce noise & pressure loss.
• Bell-mouth extends VAV operating range.
• Optional blanking segments for 3-way blow (270°) and 2-way blow (2×90° or 180°) discharge.
• Similar aesthetic to HSC-FD and HSC-AD.
• Optional CleanScreen™ smudge minimser and sweat inhibitor – patents pending.

Function

The SMARTEMP Multi-Swirl Diffuser, type MSC-FD, comprises a flat rectangular discharge face with 2, 3 or 4 swirl diffusers discharging supply air with high induction in a fixed radial pattern, producing horizontal discharge into the space.

Each swirl diffuser has 20 off-set radial swirl vanes with helical twist and cambered leading edges increase both the maximum airflow rate and the VAV operating range, whilst reducing noise and minimum permissible supply air temperature.

The diffuser is made of powder coated galvanised steel. The swirl vanes form a flush surface with the surrounding diffuser face.

Optional segment covers are available to reduce the discharge pattern from 360° to 270°, 180° or 2 x 90° (ie from four-way to three-way or two-way blow).

The high induction of swirl diffusers offers many advantages. Intense mixing at the diffuser discharge surface strongly dilutes the swirling supply air stream with large quantities of room air. Rapid temperature equalisation of the supply air with room air is achieved, preventing cold air dumping and producing uniform temperature distribution with high comfort levels in the space. Supply air stream temperature dilution also improves heating performance by reducing the bouyancy of the supply air stream. High induction produces a strong increase in the mass flow rate of the supply air stream, due to induced room air, as well as rapid discharge velocity decay. At any given airflow rate, the SMARTEMP MSC-FD swirl diffuser is suitable both for long throws (due to the high momentum of the swirling supply air stream) as well as short throws (due to its low velocity).

The SMARTEMP MSC-FD swirl diffuser may be used in CAV systems, as well as VAV systems, including with low temperature supply air (≥ 5°C). Extended VAV turndown is possible. VAV system turndown is dependent upon ΔT_supply-room (eg to approximately 25-28% at ΔTsupply-room = -16 K). Draught-free comfort is enhanced, achieving air diffusion performance index (ADPI) in excess of 90% even at specific airflow rates as low as ≈1 L/s/m². Due to the rapid discharge decay characteristics of the swirl discharge, a high maximum specific airflow rate of ≈15 L/s/m² may be achieved at 90% ADPI.

Optional CleanScreen™ includes a perforated hub that discharges clean, dehumidified supply air to screen the diffuser face from soiling and condensation due to humid air and air borne contaminants in the space. CleanScreen™ enhances hygiene, maintains clean aesthetics, and effectively eliminates on-going cleaning costs. CleanScreen™ is well suited to applications with a high concentration of pollutants (such as restaurants or near busy streets), in places of high humidity (such as the tropics or the coast) or where high infiltration may occur (such as lobbies and public spaces).

Innovation

Unique features include:

• 20 radially off-set swirl vanes per swirl diffuser increase induction.
• Swirl vanes with helical twist reduce pressure drop and increase capacity.
• Low pressure drop reduces fan energy.
• High capacity airflow reduces architectural impact.
• Flush face enhances aesthetics.

SMARTEMP MSC-FD registered designs, patent applications and granted patents are listed at smartemp.com/patents.