Application
Special characteristics
Nominal sizes
Variants
Parts and characteristics
Construction features
Materials and surfaces
Standards and guidelines
Maintenance
Functional description
Displacement flow diffusers discharge the air from air conditioning systems with a low velocity and near the floor. The low-turbulence airflow creates a pool of fresh air that covers the entire floor area. The convection from people and other heat sources causes the fresh air from the pool to rise and create comfortable conditions in the occupied zone.
This draught-free and economical type of ventilation is also suitable for large internal spaces, with several regularly arranged units.
Displacement ventilation is characterised by low airflow velocities and low turbulence. The air quality in the occupied zone is very high.
Displacement ventilation with air discharge near the floor is suitable only for cooling. The maximum supply air to room air temperature difference is –6 K.
Type QLE displacement flow diffusers are fitted with a perforated sheet metal basket as an equalising element; it distributes the supply air flow equally across the entire diffuser area. The perforated sheet metal diffuser face helps to equalise the airflow further. One-way air discharge.
With displacement ventilation, i.e. air discharge near the floor, extract air units should be installed in the upper part of a room, above the occupied zone.
Nominal sizes (B × H) | 1000 × 150 to 1500 × 750 mm |
Minimum volume flow rate, at 0.1 m/s | 15 – 115 l/s or 54 – 414 m³/h |
Maximum volume flow rate, at 0.3 m/s | 45 – 340 l/s or 162 – 1224 m³/h |
Supply air to room air temperature difference | –6 to –1 K |
Sound power level, at 0.3 m/s | 42 dB(A) max. |
Quick sizing tables provide a good overview of the volume flow rates and corresponding sound power levels and differential pressures.
QLE, sound power level, total differential pressure and near zone
1000 × 150 | 15 | 54 | 0.10 | <3 | <15 | < |
1000 × 150 | 25 | 90 | 0.17 | <3 | <15 | < |
1000 × 150 | 30 | 108 | 0.20 | <3 | <15 | < |
1000 × 150 | 45 | 162 | 0.30 | 3 | 20 | < |
1250 × 150 | 20 | 72 | 0.11 | <3 | <15 | < |
1250 × 150 | 30 | 108 | 0.16 | <3 | <15 | < |
1250 × 150 | 40 | 144 | 0.21 | <3 | 16 | < |
1250 × 150 | 55 | 198 | 0.29 | 4 | 26 | < |
1500 × 150 | 25 | 90 | 0.11 | <3 | <15 | < |
1500 × 150 | 40 | 144 | 0.18 | <3 | 16 | < |
1500 × 150 | 55 | 198 | 0.24 | 4 | 26 | < |
1500 × 150 | 70 | 252 | 0.31 | 7 | 33 | < |
1000 × 300 | 30 | 108 | 0.10 | <3 | <15 | < |
1000 × 300 | 45 | 162 | 0.15 | <3 | <15 | < |
1000 × 300 | 70 | 252 | 0.23 | 5 | 19 | < |
1000 × 300 | 90 | 324 | 0.30 | 9 | 27 | < |
1250 × 300 | 40 | 144 | 0.11 | <3 | <15 | < |
1250 × 300 | 65 | 234 | 0.17 | 5 | 17 | < |
1250 × 300 | 90 | 324 | 0.24 | 9 | 27 | < |
1250 × 300 | 115 | 414 | 0.31 | 14 | 35 | < |
1500 × 300 | 45 | 162 | 0.10 | <3 | <15 | < |
1500 × 300 | 75 | 270 | 0.17 | 6 | 21 | < |
1500 × 300 | 105 | 378 | 0.23 | 12 | 32 | < |
1500 × 300 | 135 | 486 | 0.30 | 20 | 40 | < |
1000 × 450 | 45 | 162 | 0.10 | <3 | <15 | < |
1000 × 450 | 75 | 270 | 0.17 | 3 | <15 | < |
1000 × 450 | 105 | 378 | 0.23 | 5 | 21 | < |
1000 × 450 | 135 | 486 | 0.30 | 9 | 29 | < |
1250 × 450 | 55 | 198 | 0.10 | <3 | <15 | < |
1250 × 450 | 95 | 342 | 0.17 | 4 | 17 | < |
1250 × 450 | 135 | 486 | 0.24 | 9 | 29 | < |
1250 × 450 | 170 | 612 | 0.30 | 14 | 36 | < |
1500 × 450 | 70 | 252 | 0.10 | <3 | <15 | < |
1500 × 450 | 115 | 414 | 0.17 | 7 | 23 | < |
1500 × 450 | 160 | 576 | 0.24 | 13 | 34 | < |
1500 × 450 | 205 | 738 | 0.30 | 21 | 42 | < |
1000 × 600 | 60 | 216 | 0.10 | <3 | <15 | < |
1000 × 600 | 100 | 360 | 0.17 | <3 | <15 | < |
1000 × 600 | 140 | 504 | 0.23 | 4 | 20 | < |
1000 × 600 | 180 | 648 | 0.30 | 7 | 28 | < |
1250 × 600 | 75 | 270 | 0.10 | <3 | <15 | < |
1250 × 600 | 125 | 450 | 0.17 | 3 | 17 | < |
1250 × 600 | 175 | 630 | 0.23 | 7 | 27 | < |
1250 × 600 | 225 | 810 | 0.30 | 11 | 35 | < |
1500 × 600 | 90 | 324 | 0.10 | <3 | <15 | < |
1500 × 600 | 150 | 540 | 0.17 | 5 | 22 | < |
1500 × 600 | 210 | 756 | 0.23 | 10 | 33 | 1.37 |
1500 × 600 | 270 | 972 | 0.30 | 16 | 41 | 1.84 |
1000 × 750 | 75 | 270 | 0.10 | <3 | <15 | < |
1000 × 750 | 125 | 450 | 0.17 | 3 | <15 | 1.25 |
1000 × 750 | 175 | 630 | 0.23 | 5 | 21 | 1.88 |
1000 × 750 | 225 | 810 | 0.30 | 9 | 29 | 2.57 |
1250 × 750 | 95 | 342 | 0.10 | <3 | <15 | 0.65 |
1250 × 750 | 155 | 558 | 0.17 | 4 | 17 | 1.15 |
1250 × 750 | 220 | 792 | 0.23 | 8 | 28 | 1.71 |
1250 × 750 | 280 | 1008 | 0.30 | 14 | 35 | 2.26 |
1500 × 750 | 115 | 414 | 0.10 | <3 | <15 | 0.64 |
1500 × 750 | 190 | 684 | 0.17 | 6 | 23 | 1.09 |
1500 × 750 | 265 | 954 | 0.24 | 12 | 33 | 1.56 |
1500 × 750 | 340 | 1224 | 0.30 | 20 | 41 | 2.04 |
<: 0.2 m/s are not achieved
The near zone values are based on a supply air to room air temperature difference of –3 K
Displacement flow diffusers for air discharge near the floor, suitable for comfort zones with special demands on architecture and design.
With one-way air discharge for low-turbulence displacement ventilation. Rectangular casing for installation on a wall.
Ready-to-install component which consists of a casing with spigot at the top or bottom, a perforated sheet metal basket as an equalising element, and a perforated sheet metal diffuser face.
Spigot suitable for rectangular ducts.
Sound power level of the air-regenerated noise measured according to EN ISO 5135.
Special characteristics
Materials and surfaces
Technical data
Sizing data
Air-regenerated noise
This specification text describes the general properties of the product. Texts for variants can be generated with our Easy Product Finder design programme.
Order example: QLE–U/1250×300/P1–RAL 9016
Connection | Rectangular spigot at the bottom |
Nominal size | 1250 × 300 mm |
Exposed surface | RAL 9016, traffic white, gloss level 70 % |
The nominal size (nominal width × nominal height) is equal to the discharge opening.
QLE
mm | mm | mm | kg | |
Installation and commissioning
Principal dimensions
B₁ [mm]
Width of diffuser face
B₄ [mm]
Width of a rectangular spigot
ØD [mm]
Outer diameter of the spigot
ØD₁ [mm]
Casing diameter
H₁ [mm]
Height of diffuser face
T₁ [mm]
Casing depth
T₄ [mm]
Depth of a rectangular spigot
m [kg]
Weight
Nomenclature
LWA [dB(A)]
A-weighted sound power level of air-regenerated noise
V [m³/h] and [l/s]
Volume flow rate
v0 [m/s]
Theoretical airflow velocity across the diffuser area, at a distance of 0 m from the diffuser face
Lnz [m]
Near zone of the displacement flow diffuser, where the comfort criteria may not be achieved
The near zone is at least 0.5 m, independent of the airflow velocity
At distance Lnz the airflow velocity is 0.2 m/s max., measured 0.1 m above the floor
Δtz [K]
Supply air to room air temperature difference, i.e. supply air temperature minus room temperature
Δpt [Pa]
Total differential pressure
Aeff [m²]
Effective air discharge area
All sound power levels are based on 1 pW.
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We are here for you
Please specify your message and type of request.
Tel.: +32(0)2 522 07 80 | E-mail: info@trox.be
Contact
Thank you for your message!
Your message is send and will be processed shortly.
Our department for Service-Requests will contact you asap.
For general question regarding products or services you can also call:
Tel.: +32(0)2 522 07 80 | E-mail: info@trox.be