VAV Fans Alternatives - Chicago Blower · Chicago Blower fans are recog-nized for their reliability...
Transcript of VAV Fans Alternatives - Chicago Blower · Chicago Blower fans are recog-nized for their reliability...
VAVFA
NS
VariableAirVolumeVane Axial Fans
CHICAGO BLOWER CORPORATION • GLENDALE HEIGHTS, ILLINOIS • USA
BULLETIN VAV 107
D/47VaneAxialFans
Chicago’s Design 47 Vane Axial fans are specifiedby architects, engineers and industrial firms world-wide to meet today’s environmental challenges.Chicago fans are selected for internationallyrenowned installations such as the Sidney OperaHouse, Petronas Twin Towers and United’s O’HareTerminal. Vane axial fans are chosen for their relia-bility, low initial cost and space saving configuration.Chicago’s variable air volume fans provide maximumefficiency even in unpredictable environments. Twotypes of Chicago D/47 Vane Axial direct drive fansare offered, Controllable Pitch and Adjustable Pitch.Both supply volumes to 250,000 cfm, pressures to15 sp. and sizes to 81-1/8".
Chicago Blower fans are recog-nized for their reliability andindustrial quality. Every phase offan construction is governed bystrict Chicago guidelines andstringent AMCA requirements.For application evaluations and fan recommenda-tions, contact a Chicago Blower representative.
Controllable PitchControllable Pitch fans respond automatically tochanges in temperature, humidity, air flow, gas con-centration and air quality. Clearly the best choice forvariable air volume systems, they are also used insensitive industrial applications to maintain constantconditions regardless of air demand.
Adjustable PitchAdjustable Pitch fans are specified for applicationsless critical to environmental variations, typicallyseasonal changes or system expansion. Blade pitchis adjusted externally at the hub to increase or de-crease volume and pressure.
Chicago Blower certifies that theDesign 47 Fans shown herein arelicensed to bear the AMCA Seal.The ratings are based on testsand procedures performed in ac-cordance with AMCA Publication211 and comply with the require-ments of the AMCA Certified Rat-ings Program.
2 Cover photo by Carol M. Highsmith
Optional Equipment
Streamlined Inlet BellAn inlet bell reduces entry loss and isnecessary to obtain rated performanceon open inlets.The inlet bell, or a casingextension, must be used with Control-lable pitch fans. Heavy gauge spinningbolts to inlet flange, but is not designedto support the fan.
Inlet or Outlet ConeSince a vaneaxial fan can have a diam-eter about 20% smaller than the duct, atapered cone is used to connect with ei-ther the inlet or outlet. An inlet cone mayalso be used on open fans to avoidlarge velocity pressure loss. Theflanged, punched cone bolts to fan andduct and will support fan in any positionexcept cantilever.
Access DoorThe access door is located in the op-tional inlet/outlet cone to facilitate bladeinspection, adjustment or cleaning. Thedoors are gasketed and are sealed air-tight with quick release latches.
Spool PieceA non-tapered housing extension com-plete with latched door is used in instal-lations where an access door cannot beprovided in the duct.
Guard ScreenHeavy gauge wire screen protects fanblades from foreign debris. It fits fanflange, inlet or outlet cone, or inlet bell.
For Both Adjustable Pitch andControllable Pitch Fans
CompanionAngle RingsAngle rings facilitate installationwith both flexible and slip-fit con-nections.
Mounting FeetHeavy reinforced steel plate welded tothe fan housing is suitable for floor orceiling mounting.
Vibration IsolatorsSpring type and elastomer in-shear rub-ber or neoprene mounts reduce vibra-tion transmission in any fan mountingposition.
Sound AttenuatorAttenuator reduces sound levels innoise sensitive applications. It bolts tofan inlet or outlet. Acoustical cones areavailable in lieu of standard cones.
Variable Inlet VanesManually adjusted vanes are used tovary volume when frequency changesare required. Assembly bolts to fanflange.
Electric Option includes an electric/pneumatic transducer to translateuser electric signals to the pneumatic signals required by the pilotpositioner.
Compressed air for the Electric Option is furnished either by the useror by an auxiliary pneumatic power pressure system available fromChicago Blower. The auxiliary system consists of an air compres-sor, receiver, gauges, filters, drains and air lines. It is either mountedto the fan casing or furnished loose for user mounting.
Automatic Electric ControlFor Controllable Pitch Fans
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Controllable Pitch Fanshown with optional mountingfeet. Casing extension withmotor tie supports is standardfor large NEMA frame motors.
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Fan Selection GuidelinesAltitude and Temperature Correction Factors
Design 47 fans were tested and rated onthe basis of handling air at standard den-sity of .075 lb./ft.3..
In order to select a fan for operation atany other temperature or altitude, it isnecessary to correct the pressure fromoperating density to standard density, se-lect the fan, then correct the requiredhorsepower from standard to operatingconditions.
The correction factor chart below givesthe ratio of actual to standard densitiesat various temperatures and altitudes.Apply the factors as follows:
Ps Standard = Ps Actual ÷ Factor;BHP Actual = BHP Standard x Factor
For Example
Required Duty: 30,000 CFM at 1.58" Ps
at 120°F at 4000' elevation
From chart below: Factor is .790
1.58 Actual ÷ .790 = 2.0" Ps Standard
Select fan model from selection chart:
4450 - B12 - 1160
BHP at Standard = 14.6
BHP at Operating Conditions = 14.6 x
.790 = 11.53
Changes in volume, pressure, and horsepower occur in ac-cordance with the fan laws when fan speed and/or gas den-sity changes while the fan is applied to a fixed system.Whenoperating density is other than standard (.75#/ft.3), pressuremust be corrected to standard conditions for fan selectionand horsepower must be corrected from standard to operat-ing conditions as in the example above. Performance may beadjusted according to the fan laws by changing fan speed.
Basic Fan Laws
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Total Pressure ConceptChicago Blower Design 47 perform-ance is published in terms of TotalPressure.Total Pressure = Static Pres-sure + Velocity Pressure
“Static Pressure” is unrelated to airmotion. It is a pressure that exerts aforce equal in all directions, like the airpressure in a balloon or pressure ves-sel, and can be Positive or Negative.
“Velocity Pressure” is the kinetic en-
ergy applied to motion or speed of the
air through a duct system. It is always
Positive in character.
A fan “sees” only Total Pressure. It can-
not recognize Static or Velocity Pres-
sure as separate quantities.Therefore,
the “Total Pressure Concept” must be
considered to assure that any variation
in the actual installation from the in-
stallation in which the fan was tested
is accounted for.
A fan is normally tested blowing into a
duct of the same cross-sectional area
as the fan outlet. When it is rated on
Static Pressure, the rating is based on
Total Pressure minusVelocity Pressure
in the test duct. The rating is only valid
if the fan is installed similar to the test
setup. If it is not, the true Static Pres-
sure capability will be greater or less
than the rated Static Pressure.The dif-
ference will be the difference between
actual Velocity Pressure and theVeloc-
ity Pressure based on the fan area.
Cones may be used to transition from
the fan to ducts larger or smaller than
the fan.Outlet cones may also be used
to minimize Velocity Pressure loss and
regain Static pressure. Air leaves a di-
verging discharge cone (Point B) at a
lower velocity than at the cone inlet
(Point A), therefore, at a lower Velocity
Pressure. Consequently, more of the
fan’s Total Pressure capability is avail-
able for Static Pressure than would be
For the Standard VAV cone effectivePv is: PvE = PvA - (PvA - PvB) .8
Where a cone is used, the rated StaticPressure is increased by the amountequal to PvE - PvB.
Use of Outlet or Inlet Cone
AIRFLOW
FAN
PV APV B
CONEA B
Where the fan has an open discharge
(does not blow into a cone, duct or
transition), the Velocity Pressure must
be based on the annular area; that is,
the fan casing area minus the hub
area. Since annulus velocity is gener-
ally very high, the benefit of using a
cone when discharging to atmosphere
is apparent.
Note: AMCA certified ratings do not apply
when factors are used.
available with the fan blowing into a
duct of diameter equal to the fan.
FanAreas(Ft2)
165018252000
222524502700
300033003650
402544504900
542560006650
73008112
1.481.822.18
2.703.273.98
4.915.947.27
8.8410.8013.10
16.0519.6324.12
29.0735.89
2.182.703.27
3.984.915.94
7.278.8410.80
13.1016.0519.63
24.1229.0735.89
44.1754.54
0.661.001.36
1.882.453.16
4.095.126.45
–––
–––
––
–––
–1.452.16
3.094.125.45
7.028.9811.28
14.23––
––
–––
–––
–––
5.507.469.76
12.71––
––
–––
–––
––3.22
4.796.759.05
12.0015.5820.07
25.0231.84
FAN SIZECASINGAREA
CONEAREA HUB A HUB B HUB LB HUB C
ANNULAR AREAS
Velocity Pressure = –––––––––––––Fan Area x 4005
where Fan Area = cross sectional areaat the flow point considered
CFM( )2
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*d = 1.326 x Pb°F + 460
Pt = Ps + Pv
2 2*Pv = Q = V
A x 4005 4005
Fan BHP = Q x Pt = Q x Ps6362 x nt 6362 x ns
For 3 phase motors: BHP output =E x I x ME x Pf x 1.73
746
For 3 phase motors: Kw input =E x I x Pf x 1.73
1000
For 1 phase motors: BHP output = E x I x ME x Pf746
For 1 phase motors: Kw input =E x I x Pf1000
To plot a System Curve where Ps1 and Q1 are known, usethe following formula to find other curve points:
Ps 2 = Ps1Q 2
2
Q 1
To determine round duct equivalent of rectangular duct forsame friction loss and volumetric capacity:
DR = 1.2655 (ab)3
a + b
* Formulas for d and Pv are applicable to dry air only.
( ( ( (
( (
Symbol Definition
A area (ft.2)a side a of rectangular ductb side b of rectangular duct
BHP brake horsepowerQ air volume flow (ft.3/min.)d air density (lb/ft.3)DR diameter of round ductE volts°F temperature (Fahrenheit)I amps
KW kilowattsME motor efficiency (dec.)ns fan static efficiency (dec.)nt fan total efficiency (dec.)Pb barometric pressure
(inches mercury)
Pf power factorPs static pressure
(inches WG)
Pt total pressure (inches WG)Pv velocity pressure
(inches WG)
V velocity (ft./min)
Fan Application Formulas
FanSoundData
Chicago Blower design 47 Vane AxialFans have been carefully noise tested inaccordance with AMCA Standard TestCode No. 300 for sound Rating of AirMoving Devices. Certified Sound Ratingdata is available upon request.
Sound data is as complete as it is possi-ble to provide. It permits the engineer tocompare noise levels accurately withother fans if they are also accuratelytested and rated according to the AMCACode. It permits the engineer to deter-
mine dB A levels quickly without calcula-tion, and provides the information neededto determine dBA levels for specific instal-lations.
For applications requiring lowest noise lev-els, Chicago Blower has attenuators avail-able designed specifically for Design 47characteristics. Vane Axial fans are easierand less costly to attenuate than Centrifu-gal fans. An attenuated Design 47 fan canprovide lowest noise levels at low costwithin the building space.
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EngineeringSpecifications
General:Provide variable volume vaneaxial fans asshown on the drawings of the capacities andtype as shown on the fan schedule. All fansshall be licensed to bear the AMCA Certi-fied Rating Seal for Air Performance andSound Power Level. Acceptable vendorsare: Chicago Blower Corporation.
Housings:Fan housings are to be precisely formed withintegral rolled flanges on inlet and outlet.Housings shall be mechanically expanded toinsure concentricity. Fans 36-1/2" diameterand smaller shall be made from not less than7 ga. thickness metal. Fans 40-1/4" diame-ter and larger shall be made from not lessthan 1/4" thick metal. Housings shall includenot less than 9 stationary guidevanes, innerfairing, and motor bulkhead to receive aNEMA “C”-face, flange mounted, TEAOelectric motor. Motor mounting plates willvary in thickness, but will not be less than thefollowing:
Motor mounting plates will be fabricated sothe bolts holding the C-face motor are not inshear. and if the motor is removed it can bereplaced in the original location without theuse of shims or ancillary centering devices.
Rotors:Fan blades are to be cast from A356-T51aluminum alloy. Blades shall be airfoilshaped for maximum efficiency and twistedfrom hub to tip to obtain equal air distribu-tion along the blade. Blade and shank are tobe cast integral to insure maximum bladeintegrity. Blade shall have an index markcast into the skirt for setting position ofblade. To insure wheel integrity, the methodof retaining the blade in the hub and themethod for holding the blade at the properpitch shall be separate, so the blade retain-ing mechanism is not affected by blade ad-justments. Hubs are to be one piece, castfrom A356-T6 aluminum alloy. Each bladesocket in the hub shall have vernier to beused in conjunction with blade index markfor accurately setting angle of attack of blade.
Aluminum Castings:1. Chemical verification of virgin metal shallbe provided. Chemistry of the aluminumshall be checked during the course of aheat and adjustments made as necessary.
2. Test bars shall be pored at the start andfinish of each heat.Test bars shall be sub-mitted to a qualified test laboratory for con-firmation of proper mechanical propertiesof castings. Failure of test bars will causerejection of castings made from that heat.
3. All castings will be visually inspected forobvious flaws and workmanship.
4. Since identification of cracks is importantto the integrity of castings and cracks can-not be properly identified by radiographicinspection, all casting lots shall undergosample liquid penetrant examination.Suchexamination shall be made in an approvedlaboratory by personnel qualified and cer-tified in accordance with SNT-TC-1A (Pro-cedure Qualification and Certification ofNon-Destruction Testing). Casting lots fail-ing this inspection will be rejected.
5. After castings are penetrant tested, sam-ples shall be radiographically inspected.Radiographic samples and acceptance/re-jection criteria shall conform to AluminumAssociation Standard AA-CS-M5-85.Rejection of samples will cause rejectionof entire heat.
Controllable PitchAssembly:For decreased maintenance, assembly willinclude permanently lubricated ball thrustbearings for each blade.Compatibility of turndown to zero flow shall be required when in-dicated. Loss of control signal or de-energiz-ing fan will cause blades to rotate to minimumflow position.
Actuator consists of pneumatic piston withspring return mounted integrally and rotatingwith rotor assembly. Supply air is 80 PSIand is transferred to piston by a rotatingunion. Pilot positioner, suitable for 3-15 PSIcontrol signal, is mounted externally andfeedback signal is provided by cable con-nection to piston.
A Hub B Hub C Hub3/8" 3/4" 1"
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TOTALPRESSURE
CF
Optimum Efficiency Selection Chart
A) Enter the chart with the specified volumeand static pressure to find the most efficientselection.
B) Since the chart is based on total pressure,the velocity pressure must be determinedfor the fan selected in A above and addedto the static pressure to arrive at a totalpressure.Velocity pressure is determined bythe following formula
The fan areas are on page 5.
VP = ( Fan Area x 4005 )2CFM
EXAMPLE: 40,000 CFM at 4.0" SP
A) Enter the chart with 40,000 CFM and4.0" SP. Entry falls into 80% efficiencyarea for a Model 4450-B6-1760.
B) Determine TP -TP = SP + VPTP = 4.0 = .86 = 4.86
VP = ( 10.8 x 4005 )2= .8640,000
Refer to Chicago Blower’sfan.net selection programfor performance fan curvesand sound data.
Contact your localChicago Blower salesengineer for softwareand assistance
EXAMPLE: MODEL 4450-B6-1760
The model number indicates the following:
Fan Diameter = 44-1/2"Hub Series = BNumber of Blades = 6Fan Speed = 1760 RPM
VAV FanModel
Numbers
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This chart presents a general selection method for Chicago BlowerVAV Vaneaxial Fans.All fans se-lected from this chart should be checked for exact horsepower and operating characteristics by con-sulting the individual fan curve for that selection.
USING THE SELECTION CHART
C) Re-enter the chart with 40,000 CFMand 4.86 TP. The selection remains4450-B6-1760.
Determine approximate HP
HP = CFM x TP = 40,000 x 4.86 = 38
6362 x eff 6362 x .8
C) Re-enter the chart with the specified volumeand calculated total pressure to verify youroriginal selection.
D) Approximate horsepower of the selected fanmay be determined by using the chart effi-ciency for the selected fan in the followingformula:
E) Refer to the individual fan curve for exactBHP and possible energy savings by utiliz-ing a diverging outlet cone.
HP =6362 x eff
CFM x TP
The following information is rChicago Blower Design 47 Vamation must be complete to as
TOTALPRESSURE
9
FM (X 1000)
15
10
9
8
7
6
5
4
3
2.5
2
1.5
1.0
.9
.8
.7
.6
.5
.4
.3
3 4 5 6 7 8 9 10 15 20 25 30 40 50 60 70 80 90 100 150 200
Dark Shading - 80% Efficiency
Light Shading - 75 - 80% Efficiency
Unshaded - 70-75% Efficiency
OrderingInformation
a. At what density required pressurevalue is measured.
b. At what other density, if any, fan willbe expected to operate.
5. Motor Characteristics: HP, RPM, Volts, Phase,Hertz, enclosure if other than TEAO required.
6. Accessories required.
1. Fan Size, Model Number and RPM
2. Fan Duty Requirements: CFM, Total orStatic Pressure, Gas Density, Gas Com-position (if not clean air), Maximum Tem-perature, Normal Operating Pressure.
4. Where operating density is other than.075#/ft.3 : state
required when ordering aane Axial Fan. This infor-ssure proper performance.
5425C121760
5425C61760
5425B121760
5425LB121160
5425B121160
5425B12890
5425B12890
5425-B
6-890
7300-B
6-690
4900-B
6-890
4900-B
6-890
3650-A12-890
3650-A6-890
3300-A6-890
4450C1217604025
C121760
5425LB121760
5425LB121760
6000C121760
6650C121160
6650C61160
6650C12890
6650C6 890
6650C12690
6650C6 690
6650C6 890
6000C12690
6000C121160
4900B121760
4900LB12 1760
4900LB12 1760
4900B61760
4900B121160
4900LB121160
4900B1211604900
B61160
4900B6 890
4900B6 890
4450B6 890
3650A121160
3650A61160
3650A61760
3650A61760
3650A121760
3650B121760
4025B61160
3300A12890
3300A6890
3300A61160
3300A121160
3300A61760
3300A121760
3300A121760
3300B121760
3300B121760
3000A6890
3000A6890
3000A12890
3000A121160
3000A121160
3000A121760
3000A121760
3000A61760
3000A121760
2700B123500
2700A63500
2700A121160
2700A123500
2700A12890
2700A6890
2700A6890
2450A121160
2450A61760
2450A121760
2450A63500
2450B121760
2225A121760
2225A121760
2225A61760
2225A1211602225
A121160
2000A61760
2000A121760
2225A61160
2450A123500
2450B63500
1825A63500
1650A123500
1650A63500
1825A121760
2450B123500
2450A61160 2700
A61160
2700A61160
2700B121760
2700A61760
2700A121760
2700A121760
3650C121760
3650A12890
4450B12890
4450B61160
4450B121160
4450B121160
4450B61760
4025B121760
4025B121760
4025B61760
4025B121160
4025B121160
4025B12890
4450B121760
6000C61760
6000C12890
7300C61160
6000C61160
CFM (X 1000)
7300C121160
7300C121160
8112C121160
8112C121160
8112C611608112
C12890
7300C12690
7300C12690
7300C6890
7300C6690
8112C6690
8112C12690
8112C12690
7300C12890
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Figure 1
To properly compare various methods ofvolume control, you need to look furtherthan just brake horsepower savings.Own-ers do not pay for brake horsepower, theypay for electricity consumed (input power).Inefficiencies in powered equipmentshould be included in any comparison ofvolume control methods. Figure 1 depictsthe power consumption of various typesof volume control apparatus applied to afan operating on a normal system curvewhere the required pressure varies as thesquare of the volume of air). The blue linedepicts the system brake horsepower re-quirements as a percentage of the fullload requirement. The other lines depictthe input power requirements for the var-ious types of volume control when appliedto this system in conjunction with a 90%efficient motor.
1. The green line indicates the inputpower required for a controllable pitchVAV Vane axial fan. Note at full load,since we are using a 90% efficientmotor, the input power requirement isgreater than 100%.
2. The orange line indicates the inputpower required when applying an ad-justable frequency speed controller tothe same fan (published data frommanufacturer of adjustable frequencyspeed controller). Note at full load, theinput power requirement is greaterdue to inefficiencies in both motor andspeed controller.
3.The red line depicts the input power re-quired for the same fan utilizing aninlet vane control damper.
Note that until you exceed 50% turn-down, the Controllable Pitch fan requiresless power than the adjustable frequencyspeed controller. This is due to theinefficiencies in the frequency controlapparatus.
At 80% of full load flow, the controllablepitch fan consumes 15% less power thanthe adjustable frequency and 39% lessthan a variable inlet vane control.
At 70% of full load, the controllable pitchfan consumes 10% less power than the
Compare theEfficiency of a
ControllablePitch Fan
Controllable Pitch Fan Blades
Blade angle can beadjusted while fan isoperating... providespower savings
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Figure 2
Figure 3
Figure 4
adjustable frequency and even as low as60% of full load, the savings is 5%.
It should be noted that since most vari-able volume systems operate at their de-sign point only a few hours per year,it iscommon, and good practice to select thecontrollable pitch fan to the right of itsmost efficient operating area. As the sys-tem turns down, the fan will run in the nor-mal system operating range at a highefficiency level.
Also, most variable volume systems havefixed resistances that do not vary with thevolume of air being supplied. When thesystem requires a high turn down, caremust be taken in fan selection when ad-justable speed control is used so the fanis not forced into an unstable operatingpoint at low air flow.
The most common use of the controllablepitch fan is on the system curve where thesystem pressure varies as the square ofthe volume. Figure 2 indicates such a sys-tem. The orange line indicates horse-power consumed as the fan operatesalong the system. Note the selection wasmade so the design point is to the right ofthe most efficient operating area so thateven at 75% of flow, the fan will operate atequal or higher efficiency than it does atthe design flow.
With a controllable pitch fan, you are notlimited to operating on the system asnoted above. Figure 3 indicates the oper-ation of controllable pitch fan constantstatic pressure system. With the fan de-picted, you can operate on a constantstatic pressure down to 25% of the designflow. Since the system pressure remainsconstant, the horsepower savings are notas great as for Figure 2, but still amount toa substantial energy savings.
You can also apply the controllable pitchfan to a system when a constant volumeof air is required at varying pressures. Fig-ure 4 is representative of this type of sys-tem and indicates the energy that can besaved by using the controllable pitch fan.
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Adjustable Pitch Vane Axial Fan Arrangement 4
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Controllable Pitch Vane Axial Fan Arrangement 4
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Accessories Vane Axial Fan Arrangement 4
Horizontal - Floor Mounted Mounting Feet
Horizontal - Lug Mounted
Vertical - Lug Mounted
Inlet/Outlet Cone
Inlet Bell CasingExtension
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