Post on 29-Sep-2020
AIRAH QUEENSLANDHigh Induction Air Diffusion
Specialist HVAC Systems
Air Distribution Systems
Tangential Flow
– Coanda attachment– Poor mixing– Poor temp equalisation– Dumping– Draughts– Poor heating– Ventilation effectiveness < 1
MIXED AIRFLOW
TANGENTIAL:
∆Tsupply-return = -8.0 KAirflow = 230 L/s = 6.4 L/(s•m2)
Both: stagnation (v < 0.1 m/s) , and draughts (v > 0.2 m/s)
DIFFUSE:
∆Tsupply-return = -8.2 KAirflow = 360 L/s = 10.0 L/(s•m2)
Comfort : No stagnation, and No draughts
– Rapid temp & velocity equalisation
– Even temp distribution– Draught-free– Good heating– Vent effect ≈ 1
Diffuse Flow
Diffuse Smoke Tests
• High induction
Diffuse • Adjustable Induction Outlet• Twist Outlet• Broad Multiplex Outlet
Broad Multiplex Outlets, InterContinental Hotel
Swirl Smoke Test
Cold Air Diffuser Comparison - ASHRAEHigh Induction – supply air stream temperatures
Nozzle Pre-Induction –
Rapid equalisation
Tsupply = 8 °CTroom = 24 °C
• Krantz swirl Induction –
• Extremely rapid equalisation
• Standard circular diffuser -DUMPING
• Krantz swirl diffuser –UNIFORM TEMPERATURE
• Troom = 23.4 °C ± 0.1 K• ADPI = 97%
Cold Air Diffuser Comparison - ASHRAETsupply = 8 °CTroom = 24 °C
Krantz RA-N3 Ceiling Swirl Diffuser
• Designed for cold air with dT = -15 K • Suitable for VAV with turndown to 30%• 24 radial vanes – pleasant aesthetic with small gaps between vanes• Robust design – face and vanes pressed from one metal sheet• Quiet – sound pressure ≤ NC30 per diffuser (10 dB room absorption)• 2 neck size – provides uniform aesthetic
– DN350 for 16 L/s to 175 L/s– DN500 for 48 L/s to 400 L/s
• Optional collars– to match required airflow range– 2-way blow– 3-way blow
• Optional Round Face
RA-N3: Layout for ADPI ≥ 90%
Airflows Spacing
Low Temperature VAV
Hoyts – Te Awa
Opticlean Smoke Test
Product Movie, Broad Multiplex Outlet BF-A:Animation: Broad Multiplex Outlet, BF-A
High Induction Sidewall Diffuser:
Broad Multiplex, type BF -A
High Induction Sidewall Diffuser:
Broad Multiplex – BF-A
Lengths : 950 mm 1490 mmHeights : Airflow Rates @ 20 Pa (≈NC25) / 30 Pa (≈NC30):134 mm 120 / 145 L/s 190 / 230 L/s173 mm 170 / 200 L/s 260 / 320 L/s212 mm 210 / 260 L/s 340 / 410 L/s251 mm 260 / 320 L/s 410 / 500 L/sThrow: 3 to 9 m (airflow rate and discharge pattern dependent)
Smoke Test: Broad Multiplex Outlet, BF-A
Perforated Sidewall Diffuser, Broad Multiplex Outlet BF-A:
Krantz IN-V2 Induction Diffuser• Designed for dT = -12 K to +5 K; Turndown to 30%
• Variable Discharge Direction
Adjustable Swirl - Horizontal
Adjustable Swirl - Vertical
Heating Tests
Horizontal vs Vertical DischargeTroom warm up from 12°C to 19 °CTsupply = 27°CHdischarge = 6 mHmeasurement = 300 mm above floor∆thorizontal discharge = 2.5 hours∆tvertical discharge = 25 minutes
RA-V
• Manual, Electric
• DN200 – DN500
• Compact
• $
RA-V2
• Manual, Electric, Thermal
• DN250 – DN710
• Bulky
• $$
DD-VL
• Manual, Electric
• DN315 – DN630
• Extremely Quiet
• $$$
DD-VG
• Manual, Electric
• DN315 – DN630
• Very Long Throw
• $$$$
Swirl Diffusers with Adjustable Direction
• Thermally Powered Discharge Direction Adjustment
Adjustable Discharge Direction
DD-VL: Concert Hall, Hamilton, NZ DD-VZ: Sydney Olympics 2000, AU
Adjustable Discharge Direction
DD-VL: South Pacific TV Studios, NZ RA-V2: Exhibition, South Korea
TV Studio: ATP 7, Sydney
Side-blow Swirl – long throw
High Induction Air Diffusionfor
AIRAH Queensland
THANK YOU