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Trane TRG-TRC013-EN period three, VAV System, Air Conditioning Fans, K 9e“5, g HN, supply fan

Models: TRG-TRC013-EN

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Page 46

Image 46

Air Conditioning Fans

period three

g HN

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VAV System

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VAV boxthermostat

g HO

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Page 46

Image 46

Trane TRG-TRC013-EN period three, VAV System, Air Conditioning Fans, K 9e“5, g HN, supply fan, thermostat, g HO, VAV box

Contents

Page THE TRANE COMPANY Attn Applications Engineering BUSINESS REPLY MAILBUSINESS REPLY MAIL 3600 Pammel Creek Road La Crosse WIAir Conditioning Fans Comment CardResponse Card One of the Equipment Seriesp e The Trane Company Worldwide Applied Systems GroupAir Conditioning Fans A Trane Air Conditioning Clinic99999999999999999999999999999 caQ3caM6793O Air Conditioning Fans axial centrifugalAir Conditioning Fans period oneMeasuring Pressure atmospheric ductpressure pressureR-2 x”rwt Positive Duct Pressurefwt” p 2 p ”tvp rp S” r“- 4 jK 7683-- r-“4lcwt are “water gage” wg and “water column” wcpressure Inclined Manometerduct reservoirTotal Pressure Velocity Pressure vs. Static Pressureg DC Velocity Pressure vs. Static PressureVelocity Pressure vs. Static Pressure damper fully openg DD Measuring Static PressureVelocity Pressure vs. Static Pressure g DEMeasuring Total Pressure Fan Performance Test g DGVelocity V = Constant ⋅ √ Pρ Determining Fan AirflowVelocity Pressure Pv = Pt - P s Airflow = Velocity ⋅ Fan Outlet Areastatic pressure Plotting Fan Performance PointsPlotting Fan Performance Points 2.0 in. H2Oairflow Fan Performance Curvestatic pressure airflowFan Speed Input Power Fan SurgeFan Surge Line Percent of Wide-OpenAirflowPp” -p” Tabular Performance Datafan’s speed and input power requirement g EGSystem Resistance System ResistanceAirflow System Resistance CurveStatic Pressure Static PressureSystem Resistance Curve Fan - System InteractionFan - System Interaction Higher System Resistance Lower System ResistanceStatic Efficiency Power Out Static Efficiency SE = Power InSE = Constant ⋅ Input Power Airflow ⋅ Static Pressure1.65 m3/s ⋅ 491 Pa 3,500 cfm ⋅ 2.0 in. H2O= 55% ⋅ 1.5 kWresistance curve Constant-VolumeSystemdesign system pressureg FH Variable-PitchVaneaxial Fanvariable-pitch blades 85% 80% 70% total pressuresurge region airflowg FM total pressuresurge region anglAir Conditioning Fans period twoCentrifugal Fan g FNcwt ux r2 - PM2 up” PM up” r-” -t Forward Curved FanForward Curved Fan cwt r50 to 65% Forward Curved Fanstatic efficiency applicationBackward Inclined Fan backward inclined FC vs. BI Fansforward curved Backward Inclined FanBackward Inclined Fan cwt p“xrpbackward inclined Backward Curved FanAirfoil Fan backward curvedstatic efficiency Plug or Plenum FanAirfoil Fan 80 to 86%straightening vanes fan wheel or impeller Vaneaxial Fang HF application Vaneaxial FanVariable-PitchVaneaxial Fan static efficiencyairflow surge regionpressure g HIBackward inclined BI or airfoil AF Fan SelectionForward curved FC VaneaxialAir Conditioning Fans period threeVAV System K 9e“5VAV System Riding the Fan Curve“Riding the Fan Curve” S” p eKeForward Curved Centrifugal Fan Fan Control Loop VAV System Modulation Curve Discharge dampers Inlet vanes Fan-speedcontrol Methods of Fan Capacity ControlDischarge Dampers Variable-pitchblade controlDischarge Dampers upward. 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 pressureInlet Vanes Inlet VanesInlet Vanes upward. 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 pressureFan-SpeedControl Fan-SpeedControlg MF Variable-PitchBlade Controlp“-”vKe variable-pitch bladescwt t e eK/ up”discharge Fan Control Comparisonpower design airflowAir Conditioning Fans period fourg MI sensor System Static-PressureControlcontroller VAV supplyterminal units fanOptimized Static-PressureControl System Effect System EffectAcoustics Avoid rectangular sound traps, if possible Acoustical GuidelinesMinimize system effects Use adequate vibration isolation1 Air Density Ratio = Effect of Actual Conditions5 Poweractual = Air Density Ratio ⋅ Powerstandard DensityactualEquipment Certification Standards PurposeReview-PeriodOne period fiveAir Conditioning Fans axial centrifugal Review-PeriodTwoReview-PeriodThree “Riding the fan curve” Discharge dampersg NO Review-PeriodFourApplication considerations System static-pressurecontrol System effectcp”t Kx Page NLt -”trp” wp”s“t wxvwt PO up”4 DDList two possible causes of system effectE F 64 x”4 R8 j78 pl e F 82A98 u- j7 bndb Kx cbt L“riding the fan curve” K -tsx 9bw5 EOCF8P8EOI yvi8yveCDF8grgAc8hrf8yvi8yveCDF8DCPP8gr FLCC t e