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Trane TRG-TRC013-EN manual Methods of Fan Capacity Control, Discharge Dampers, g IH, supply fan

Models: TRG-TRC013-EN

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Page 51

Methods of Fan Capacity Control

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Methods of Fan Capacity Control

▲Discharge dampers

▲Inlet vanes

▲Fan-speed control

▲Variable-pitch blade control

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Image 51

Trane TRG-TRC013-EN Methods of Fan Capacity Control, Discharge Dampers, Discharge dampers Inlet vanes Fan-speedcontrol

Contents

Page 3600 Pammel Creek Road La Crosse WI BUSINESS REPLY MAILBUSINESS REPLY MAIL THE TRANE COMPANY Attn Applications EngineeringOne of the Equipment Series Comment CardResponse Card Air Conditioning FansWorldwide Applied Systems Group p e The Trane CompanyA Trane Air Conditioning Clinic Air Conditioning Fans99999999999999999999999999999 caQ3caM6793O axial centrifugal Air Conditioning Fansatmospheric ductpressure pressure period oneMeasuring Pressure Air Conditioning Fansare “water gage” wg and “water column” wc Positive Duct Pressurefwt” p 2 p ”tvp rp S” r“- 4 jK 7683-- r-“4lcwt R-2 x”rwtreservoir Inclined Manometerduct pressureVelocity Pressure vs. Static Pressure Total Pressuredamper fully open Velocity Pressure vs. Static PressureVelocity Pressure vs. Static Pressure g DCg DE Measuring Static PressureVelocity Pressure vs. Static Pressure g DDMeasuring Total Pressure g DG Fan Performance TestAirflow = Velocity ⋅ Fan Outlet Area Determining Fan AirflowVelocity Pressure Pv = Pt - P s Velocity V = Constant ⋅ √ Pρ2.0 in. H2O Plotting Fan Performance PointsPlotting Fan Performance Points static pressureairflow Fan Performance Curvestatic pressure airflowFan Speed Fan Surge Input PowerPercent of Wide-OpenAirflow Fan Surge Lineg EG Tabular Performance Datafan’s speed and input power requirement Pp” -p”System Resistance System ResistanceStatic Pressure System Resistance CurveStatic Pressure AirflowFan - System Interaction System Resistance CurveFan - System Interaction Lower System Resistance Higher System ResistanceAirflow ⋅ Static Pressure Power Out Static Efficiency SE = Power InSE = Constant ⋅ Input Power Static Efficiency⋅ 1.5 kW 3,500 cfm ⋅ 2.0 in. H2O= 55% 1.65 m3/s ⋅ 491 Papressure Constant-VolumeSystemdesign system resistance curveVariable-PitchVaneaxial Fan g FHvariable-pitch blades airflow total pressuresurge region 85% 80% 70%angl total pressuresurge region g FMg FN period twoCentrifugal Fan Air Conditioning Fanscwt r Forward Curved FanForward Curved Fan cwt ux r2 - PM2 up” PM up” r-” -tapplication Forward Curved Fanstatic efficiency 50 to 65%Backward Inclined Fan Backward Inclined Fan FC vs. BI Fansforward curved backward inclinedcwt p“xrp Backward Inclined Fanbackward curved Backward Curved FanAirfoil Fan backward inclined80 to 86% Plug or Plenum FanAirfoil Fan static efficiencyVaneaxial Fan straightening vanes fan wheel or impellerg HF static efficiency Vaneaxial FanVariable-PitchVaneaxial Fan applicationg HI surge regionpressure airflowVaneaxial Fan SelectionForward curved FC Backward inclined BI or airfoil AFK 9e“5 period threeVAV System Air Conditioning FansS” p eKe Riding the Fan Curve“Riding the Fan Curve” VAV SystemForward Curved Centrifugal Fan Fan Control Loop VAV System Modulation Curve Variable-pitchblade control Methods of Fan Capacity ControlDischarge Dampers Discharge dampers Inlet vanes Fan-speedcontrolupward. The fan begins to “ride up” its constant-speedperformance curve toward f, from the design operating point e, trying to balance with this new system resistance curve. As a result, the fan delivers a lower airflow at a higher static pressure Discharge DampersInlet Vanes Inlet Vanesupward. The fan begins to “ride up” its current vane position curve toward f, from the design operating point e, trying to balance with this new system resistance curve. As a result, the fan delivers a lower airflow at a higher static pressure Inlet VanesFan-SpeedControl Fan-SpeedControlvariable-pitch blades Variable-PitchBlade Controlp“-”vKe g MFe eK/ up” cwt tdesign airflow Fan Control Comparisonpower dischargeperiod four Air Conditioning Fansg MI VAV supplyterminal units fan System Static-PressureControlcontroller sensorOptimized Static-PressureControl System Effect System EffectAcoustics Use adequate vibration isolation Acoustical GuidelinesMinimize system effects Avoid rectangular sound traps, if possibleDensityactual Effect of Actual Conditions5 Poweractual = Air Density Ratio ⋅ Powerstandard 1 Air Density Ratio =Purpose Equipment Certification Standardsperiod five Review-PeriodOneAir Conditioning Fans “Riding the fan curve” Discharge dampers Review-PeriodTwoReview-PeriodThree axial centrifugalSystem static-pressurecontrol System effect Review-PeriodFourApplication considerations g NOcp”t Kx Page DDList two possible causes of system effect NLt -”trp” wp”s“t wxvwt PO up”4E F 64 x”4 R8 j78 pl e F 82A98 u- j7 cbt L bndb Kx“riding the fan curve” K -tsx 9bw5 FLCC t e yvi8yveCDF8grgAc8hrf8yvi8yveCDF8DCPP8gr EOCF8P8EOI