Understanding and Combating System Effects - staging.amca.org AMC… · Understanding and Combating...
Transcript of Understanding and Combating System Effects - staging.amca.org AMC… · Understanding and Combating...
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Understanding and Combating System EffectsMark STEVENS, AMCA International, Inc.Alain GUEDEL, CETIAT
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Learning Objectives• Basic air systems• What’s System Effect?• Inlet versus outlet System Effect• System Effect’s effect on power consumption• Is System Effect a common occurrence?• Rules of thumb
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Basic Air Systems
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Fan Air Performance Testing
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AMCA Standard 210
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Test Fan
Auxiliary Fan
NozzlesFan Airflow
Piezometer Ring Fan Static Pressure
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Nozzle Wall
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AMCA 210 Test Results
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0 2 4 6 8 10 12Air Flow, Q
Pres
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, P
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0.5
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2.5
Power, H
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AMCA Standards 500-D & -L
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Test Damper
Auxiliary Fan
NozzlesDamper Airflow
Piezometer Ring Damper Pressure Drop
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Fan Operating Point
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Operating Point
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Air Flow, Q
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AMCA 500-D Test Results
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Speed Change
New Operating PointNew speed
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Air Flow, Q
Pres
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, P Operating Point
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Damper Opening
New System
New Operating Point
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Air Flow, Q
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Operating Point
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What’s System Effect?
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Test Fan
Installation ≠ Test Setup
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Auxiliary Fan
NozzlesFan Airflow
Piezometer Ring Fan Static Pressure
Installed Fan
PlenumPlenum
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AMCA Catalog Ratings “Performance certified is for
installation type:
A: Free inlet, Free outlet”B: Free inlet, Ducted outlet”C: Ducted inlet, Free outlet”D: Ducted inlet, Ducted outlet”
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Duct Setups Match, But…
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Inlet Versus OutletSystem Effect
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Outlet System Effect
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Outlet System Effect
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ACTUAL SYSTEM WITH SYSTEM EFFECT
CALCULATED SYSTEM WITH NO ALLOWANCE FOR SYSTEM EFFECT
SYSTEM EFFECT LOSS AT DESIGN AIRFLOW
AIRFLOW DEFICIENCY
DES
IGN
RES
ISTA
NC
E
DESIGN AIRFLOW
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Outlet System EffectSE = pc + SEoWhere:• pc = Conventional pressure loss• SEo = Additional pressure loss due to non-uniform
flow• SEo = C x pfd2
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Inlet System Effect
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FAN PERFORMANCE CURVE WITH SYSTEM EFFECT
FAN PERFORMANCE CURVE
AIRFLOW DEFICIENCY, ΔqV1
SYST
EM R
ESIS
TAN
CE
DESIGN AIRFLOW
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Inlet System Effect
fsV pq /1=ξ
“Nearly” constant
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System Effect CalculationAMCA Publication 201
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AMCA Publication 201Plenum Example
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Plenum
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E-F duct friction at 5000CMH (Q) 747 Pa (duct design)E contraction loss-plenum to duct 50 Pa (part of duct system)E PS energy required to create velocity at E 125 Pa (part of duct system)D PV loss (also PT loss) at D as result of air velocity decrease 0 Pa
PS does not change from duct to plenum at D C-D outlet duct on fan as tested 0 Pa
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REQUIRED Fan PS 922 Pa
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Plenum
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D-E duct friction at 5000CMH (Q) 747 Pa (duct design)D contraction loss-plenum to duct 50 Pa (part of duct system)D PS energy required to create velocity at D 125 Pa (part of duct system)
B-C SEF 149 PaB-C PV loss (also PT loss) at C as result of air velocity decrease 0 Pa
PS does not change from duct to plenum at C ------------------
REQUIRED Fan PS 1071 Pa
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AMCA 201 ExampleAssuming:Use of the same fan for both systemsCan attain both operating points with a
change in speed
Speed change ratio; (1071/922)0.5 = 1.08
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PC = NCN( ) P
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AMCA 201 Example
1.083 = 1.25 The increased in power consumption to
overcome System Effect is about 25%
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HC =NCN( ) H
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Is System Effect a Common Occurrence?
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Rules of Thumb
Minimum 2.5 duct diameters on outlet
Minimum 3 to 5 duct diameters on inlet
Avoid inlet swirl
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RecommendationsAllow enough space in the building design to
allow for appropriate fan connections to the systemUse allowances in the design calculations
when space or other factors dictate less than optimum arrangement of the fan outlet and inlet connections Include adequate allowance for the effect of
all accessories and appurtenances on the performance of the system and the fan
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Recommendations• Be aware of ISO TR 16219• Make liberal use of AMCA’s Fan Application
Manual• AMCA 201 (under review)• AMCA 202• AMCA 203• AMCA 205
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Questions?
Mark StevensExecutive Director
AMCA [email protected]
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Understanding and Combating System EffectsLearning ObjectivesBasic Air SystemsFan Air Performance TestingAMCA Standard 210Nozzle WallAMCA 210 Test ResultsAMCA Standards 500-D & -LFan Operating PointSpeed ChangeDamper OpeningWhat’s System Effect?Installation ≠ Test SetupAMCA Catalog RatingsDuct Setups Match, But…Slide Number 16Inlet Versus Outlet�System EffectOutlet System EffectOutlet System EffectOutlet System EffectInlet System EffectInlet System EffectSystem Effect Calculation�AMCA Publication 201AMCA Publication 201�Plenum ExampleSlide Number 25Slide Number 26Slide Number 27AMCA 201 ExampleAMCA 201 ExampleIs System Effect a �Common Occurrence?Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35Slide Number 36Slide Number 37Slide Number 38Slide Number 39Slide Number 40Slide Number 41Slide Number 42Slide Number 43Slide Number 44Slide Number 45Slide Number 46Slide Number 47Slide Number 48Slide Number 49Slide Number 50Slide Number 51Slide Number 52Slide Number 53Slide Number 54Slide Number 55Slide Number 56Slide Number 57Slide Number 58Slide Number 59Rules of ThumbRecommendationsRecommendationsQuestions?