New Induced Jet Fan Simulation 1-7-12 New Design

8/10/2019 New Induced Jet Fan Simulation 1-7-12 New Design

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Content

Introduction

Design System

Jet Fan Products Line.

Case Study.

Q&A


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Introduction


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Jet Fan

Tunnel Jet FanInduced Jet Fan

Velocity Profile

Thrust force :The momentum fluxat fan

outlet, that is the product of the mass flow

and average velocity

FT= d * Q * v (N)

d = Air density

Q = Air volume

v = Air velocity


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--Discharge of fluid from an opening into a

larger body of the same or similar fluid

Definition of Jet


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Categories of Jet

Based on flow profile

Free air jet (not obstructed or affected by walls ,

ceilings or other surfaces)


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Free Air Jet

Chart for determining Centerline Velocities of Axial and Radial Jet

Vx = Centerline velocity at distance x from outlet, m/s

V0= Average initial velocity at discharge, m/s

X = Distance from outlet to measurement of centerline velocity Vx, m

A0= Core area of Neck area, m2

Kc = Centerline velocity constant

Zone 3 Zone 4Zone 2Zone 1


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Jet Expansion Zones and

Center Line Velocity

Zone 1 -- core zone

Zone 2 -- characteristic

decay zone [plane

jet],

Zone 3ax isymmetricdecay zone [three-

dimensional free air

jet]

Zone 4 -- terminal zone

Chart for determining Centerline Velocities of Axial and Radial Jet

Free Air Jet


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Throw : Horizontal or vertical axial distance an

airstream travels after leaving an air outlet beforemaximum stream velocity is reduced to a specified

terminal velocity

- Maximum throw is usually defined as thedistance from the outlet to where the centerline

velocity is 0.25m/s.

Throw, X =1.13 KcQ0VxAo

Q0= Discharge from outlet, CMS

Throw Distance


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Example: Kruger Jet Fan IJA 355

Outlet velocity, Vo= 18.2 m/s, Q0= 6480 CMH

Final Entrainment Ratios at centerline velocity,

Vx= 1.12 m/s (Distance = 36 m)

Qx= 2 x 18.2 /1.12 x 6480= 210,600 CMH

Entrainment Ratios


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Design System


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Normal Fan

Smoke Fan (Heat resistance)

Temperature

Air Direction

Non-Reversible

Reversible

Jet Fans


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Car park Design Condition

Air Ventilation

Law 4 air change

Normal case 6 air change

Fire case 10 air change

CO 50 ppmCO2 ?

Temperature 40 deg C (104 F)Air velocity 0.2 mps (40 fpm)


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1. Calculation by Jet Fan Velocity ProfileNumber of jet fans required N = A / a

Where: A= Actual parking area (m2)

a= Jet fan area (m2)

N = A / (d x w)

Where: A = actual parking area(m2)

A = total car park areaarea of all fanrooms/plan, rooms/staircase/ramp, etc.

d = Throw distance (m)

w = Flow width (m)

Induced Jet Fan Quantity


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2. Calculation by Jet Fan Air CapacityNumber of jet fans required N = Q / q

Where: Q= total ventilation flow rate bared by jet fan

q= single jet fan flow rate

Q = 3 ACH x A x H


A = total car park areaarea of all fan

rooms/plant, rooms/staircase/ramp, etc.H = floor to ceiling distance (m)

Induced Jet Fan Quantity


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Optimal sets of Exhaust & Supply fans dependent

of the fire zoning.

Where : The Supply Fan capacity are typically sized

@80% of the Exhaust Fan capacity to keepthe enclosure negatively pressurized.

Main Exhaust &Supply Fan

Quantity


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Q = 6~10 ACH x A x H


A = total car park areaarea of all fanrooms/plant, rooms/staircase/ramp, etc.H = floor to ceiling distance (m)


Quantity


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Time(Hr) CO (ppm) VentilationASHRAE 8

1

9

35

7.6 L/s.m2

(1.5 cfm/ft2)

ICBO 8

1

50

200

7.6 L/s.m2

(1.5 cfm/ft2)

NIOSH/OSHA 8

Ceiling

35

200

-

BOCA - - 6 ACH

SBCCI - - 6~7 ACH

NFPA - - 6 ACH

ACGIH 8 25 -

Regional and Country Standard


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Time(Hr) CO (ppm) Ventilation

Canada 8

1

11/13

25/30

-

Finland 8

15 minutes

30

75

2.7 L/s.m2

(0.53 cfm/ft2)

France Ceiling

25 minutes

200

100

165 L/s. car

(350cfm/car)

Germany - - 3.3 L/s.m2(0.66 cfm/ft2)

Regional and Country Standards


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Time(Hr) CO (ppm) Ventilation

Japan/South

Korea

- - 6.35~7.62

L/s.m2

(1.25~1.5

cfm/ft2)

Netherland 0.5 200 -Sweden - - .91 L/s.m2

(0.18 cfm/ft2)

Australia 1

8

60

30

6 ACH

U.K. 8

15 minutes

50

300

6~10ACH

Regional and Country Standards


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Australian Standard

AS 1668.2-1991


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Singapore Standard

CP 13-1999


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Car Park Design Duct System


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Car Park Design Ductless System


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Comparison Of Ducted and Ductless system

Ducted

System

Ductless

System

Fresh Air Fan

Exhaust AirFan

Ducted -

Jet Fan -

Induced Air -

Comparison


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S


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Duct System

D l S


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Ductless System

M i d t


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Main advantages of the Induced Jet Fan

System compared to ducted system

Smoke control / defined smoke pattern

Lower pressure drop

No ducting to block, leak or become damaged

Lower power consumption

Less install emergency power required

Lower noise level

Main advantages

M i d t


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Main advantages of the Induced Jet Fan

System compared to ducted system

Smoke and heat removed from the

garage during fire

Major building cost savingLittle need for installation coordination

Improved access for the fire service

Safer, lighter, more open environment Increased number of parking bay

Main advantages

I d d J t F C t l


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Control Strategy

On/OffControl

-First Set PointLow Speedof First Stage Fan(s)

-Second Set PointHighSpeed or Second Stage

Fan(s)

-Alarm PointAll Fans Withinthe Same Fire CompartmentHi Speed

Control Strategy

VFD/VSDControl

-First Set PointMin Speed(Min ventilation rate) ~ Speed

Increase Proportionally~

-Second Set PointMaxSpeed

-Alarm PointAll Fans Withinthe Same Fire CompartmentMax Speed

Induced Jet Fan Control

PLC C t l


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PLC Advantages

1.Operating System (O/S) is table

2.Handling the repeating operation in programming

3.To substitute the traditional relay circuit

a) Relay fail

b) The delay when the relay On/Off

4.Integrated with Industrial Network SCADA System

(Supervisory Control And Data Acquisition System)

PLC Control


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Model DCO-S2

Dual CO-Temp Sensors

Product Description

A digital ventilation controller

specifically designed to monitor

carbon monoxide and temperature in

the car parks.

To regulate the environmentaccording to these two parameters.


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Dual CO-Temp SensorsModel DCO-S2

CO Measurement:Operating principle ... .Gas sensitive thick film material(MMOS) with active carbon filter

Gas sample mode .. DiffusionResponse time (1/e) .. Less 2 min. diffusion timeMeasurement range ... 0 ~ 100 ppm

Extended measurement range ..101 ~ 255 ppmAccuracy ... ..Better than +/- 10 ppmAnnual zero drift ... ..< 5%Resolution . ..1 ppm

Temperature Measurement:Operating principle ... .NTC thermistorMeasuring range ... .0 to 50oCAccuracy ... .. 0.75oCDigital resolution .. ..0.1oC


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General Performance:Compliance with .EMC Directive 89/336/EECOperating temperature range 0 to 45oCOperating humidity range ..0 to 100% RH (non-condensing)Maintenance interval ..2 years with Self Calibration Algorithm (SCA)enabled

Electrical:Power input .Min. 18VDC / 22 VAC, max. 30VDC / 29 VACPower consumption < 2 watts averageWiring connections .Terminal block (see figure) ,2mm2maximum

Digital interface (options).: . ..RS232 cable with sensor slide connector/com driver (A232 cable)Accessories ..-K duct mount aspiration box for duct

measurement

CO S


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Outputs:Linear analog controller outputs .0 to 10V x 2, Rout < 100 ohm,

RLoad > 5 kohm on Out 1 & Out2.

4 to 20mA x 2, RLoad < 500 ohm on

AN1 & 2 (V/I jumper select)

D/A resolution .. 8 bits, 39mV / 0.062mA per step

D/A conversion accuracy Within 2% of readingRelay . Out3 & 4, isolated N.O. 1mA/5V up to

1A/50VAC/24VDC

Display .. 4 digit LCD display with ppm / oC indicatorPushbutton For on-board zero calibration


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CO monitor & Control System Advantages

1.Reduce ventilation to save energy when the car park

usage is low

2.Maintain ventilation to ensure acceptable car park

environment when car park usage is high

3.CO monitor & Control is the actual demandmeasurement

CO Monitor & Control


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How to determine the Nos. of sensor points required?

The number of sensing points is calculated using the

guidelines of AS1668.2 with the considerations given

above.N = A/1000 x SQRT(L /W)

Where N = Nos. of sensing point

A = Area of car park in sq meters

L = Length of car park in metersW = Width of car park in metersSQRT = Square root

Nos. of sensor points

Wh t l th ?


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Sensor shall be installed at 0.9m 1.8m abovefloor level (AS 1668.2).

However for practical reason (in order to avoidvandalism), the sensors can be installed just above

1.8m.

Where to place the sensors ?

Th 4 l l f V til ti t


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The 4 levels of Ventilation system

No ventilation required

CO 25 ppm and Temp below 25OC the

system no ventilation required.

CO above 25 ppm and Temp higherthan 25OC alarm

Additional jet fans are started with Low

speed. Related Main Exhaust andSupply Fan will start with Low speed.

Step 1

Step 2

Th 4 l l f V til ti t


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CO equal of higher than 50 ppm, Temp

reach 40OC alarm

Related The jet fans and Main Exhaust Fan

Main Supply Fan are switched to high speed.

Step 3

The 4 le els of Ventilation s stem


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Fire Ventilation

The fire is automatically detected and the

smoke/ the heat is extracted according to

the location of the fire.

Some jet fans are switched off to avoidturbulent air (Necessary jet fans are on to

control the smoke towards the exhaust

shaft).

All the Main fan (Exhaust& Supply) shouldbe on at high speed.

Step 4

Normal Conditions


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Air Flow for Normal Conditions

Normal Conditions

Normal Conditions


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Legend:

Induced Jet Fan

Exhaust Fan

Airflow

Well defined air flow for

Normal

Conditions

Normal Conditions

Fire Conditions
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Fire Conditions

Fire Conditions


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Activated Induced Jet Fan Exhaust Fan Car on Fire Airflow

Fire Conditions

System Layouts
http://www.wittfan.com/lang_idp/ventoff.htmlhttp://www.wittfan.com/lang_idp/ventoff.html


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System Layouts

Linear flow

System Layouts


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Linear flow

Jet Fans pointing in the same general direction to

move air from one end of a car park to the other.

Similar to a traditional mechanically ducted system.

For this scheme to work effectively, the exhaust and

supply points should be located on opposing ends of

the car park across its longest dimensions.

System Layouts

System Layouts


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System Layouts

Circular Mixing

System Layouts


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Circular Mixing

Jet Fans positioned around the car park to generate

air movement in a circular pattern.

Air gets mixed and stirred throughout the entire area,which provides greater dilution of pollutants within the

car park.

Suitable for smaller car parks where the length andwidth of the car park is less than 50m.

System Layouts

System Layouts


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System Layouts

Assisted Natural Flow

System Layouts


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Assisted Natural Flow

AS/NZS1668.2:2002 states that where exhaust air

outlets are further than 40m away from supply air

intakes, consideration should be given to potentially

harmful effects of short circuiting, stack effect, windforces and interaction with other systems.

Where the distance is greater than 75m, the ability of

a ventilation system to effectively dilute polluted air inall parts of the car park should be demonstrated.

System Layouts

General Design Approach


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General Design Approach

Architecturalsurvey of facility

Determineventilation

requirement andobstacles inenclosure

Placement offans and design

of air circuits

Adjusting volumeflow rate of

induced jet fansand main supply

& exhaust fans

Verifyeffectiveness of

ventilationsystem design

by CFD

Deliver CFDoutputs and

graphs

CFD Simulation


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CFD SimulationCUSTOMERENQUIRY

Feasibility

Study

Info

Sufficient?

Consider redesign or

seek other simulation

provider

Model Set-up &

Simulation

Collection of Essential

Information(design

criteria, spec, CAD

Drawing)

Result

Analysis

RESULTOUTPUT

Design

Modification

& Revision

CFD Simulation


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Jet Fan Products Line



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Model : IJA,

Standard galvanizematerial

Model : IJC II,

Standard Mild steel

with painting

Model : IJC,



Centrifugal Axial

Model : IJA,

Option with painting

Model : IJM-N,


Mixed flow

Model : IJM,

Standard steel with

painting

Cent Jet Fan Positioning


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Kruger Centrifugal Jet Fan


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Kruger Centrifugal Jet Fan

(IJC II 100)

Model: IJC II 100

Type: Centrifugal Jet FanMotor: 2 Speed, maximum power of 2.2 Kw

Standard: BS EN12101-3: 2002 Rated

Temperature: 300C for 2 hour



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Kruger Axial Jet Fan : IJA


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The induced Jet Fans are specifically designed for the

system. They are usually very low noise level and

temperature max. 400C for 2 hours according to BSEN12101-3 : 2002

Kruger Axial Jet Fan : IJA

Axial Jet Fan Positioning


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Kruger Mixed Jet Fan : IJM


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Kruger Mixed Jet Fan : IJM

Mixed Jet Fan Positioning


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Mixed Jet Fan Positioning

Kruger Mixed Jet Fan : IJM-N


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Kruger Mixed Jet Fan : IJM-N


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Jet Profile


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Jet Profile

Actual Test Data


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Actual Test Data

Actual Test Data Plan View


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ctua est ata a e



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Actual Test Data Side View


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Test Report


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p


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Case Study

Case Study


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y

Condition

- Normal Case

- Non-Reversible

- Air ventilation: 6 Air change

- Exhaust air 60,000 CFM- Supply air 60,000 CFM

- CO < 50 ppm

-

Temperature < 40oC

-

Air movement velocity > 0.2 m/s (40 fpm)

Case Study


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Assumptions& Settings

-Floor height of car park: 2.5 m

- Car modeling assumption

- 3 cold cars, 3 hot cars, 131 still cars

- Car size: 1.5m x 3.5m x 1.2m

- Exhaust from car: 50mm x 50mm x 50mm

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Case Study


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Assumptions

& Settings

-CO emission

- Cold car : 3.66 g/min- Hot car : 1.89 g/min

-

Heat of exhaust gas- Cold car : 2,646W- Hot car : 1,764W

Note : Cold car = A car just started upHot car = A car just entering car park

y

Case Study


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15,000 CFM

15,000 CFM

15,000 CFM 15,000 CFM

15,000 CFM

15,000 CFM

15,000 CFM

15,000 CFM

y

Case Study


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15,000 CFM

15,000 CFM

15,000 CFM 15,000 CFM

15,000 CFM

15,000 CFM

15,000 CFM

15,000 CFM

y

Case Study


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y

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10,000 CFM

10,000 CFM

20,000 CFM 20,000 CFM

10,000 CFM

10,000 CFM

20,000 CFM

20,000 CFM

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Summary


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Q&A


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THANK YOU

Documents

New Induced Jet Fan Simulation 1-7-12 New Design