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Trane TRG-TRC013-EN System Static-PressureControl, controller, sensor, g MM, static pressure

Models: TRG-TRC013-EN

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Page 60

Image 60

System Static-Pressure Control

controller

static pressure

sensor

VAV

supplyterminal units fan

g MM

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r s

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location for all load conditions can be difficult—often determined by trial and error or by using multiple sensors.

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Page 60

Image 60

Trane TRG-TRC013-EN System Static-PressureControl, controller, sensor, VAV supplyterminal units fan, g MM, static pressure

Contents

Page BUSINESS REPLY MAIL BUSINESS REPLY MAILTHE TRANE COMPANY Attn Applications Engineering 3600 Pammel Creek Road La Crosse WIComment Card Response CardAir Conditioning Fans 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 centrifugalperiod one Measuring PressureAir Conditioning Fans atmospheric ductpressure pressurePositive Duct Pressure fwt” p 2 p ”tvp rp S” r“- 4 jK 7683-- r-“4lcwtR-2 x”rwt are “water gage” wg and “water column” wcInclined Manometer ductpressure reservoirTotal Pressure Velocity Pressure vs. Static PressureVelocity Pressure vs. Static Pressure Velocity Pressure vs. Static Pressureg DC damper fully openMeasuring Static Pressure Velocity Pressure vs. Static Pressureg DD g DEMeasuring Total Pressure Fan Performance Test g DGDetermining Fan Airflow Velocity Pressure Pv = Pt - P sVelocity V = Constant ⋅ √ Pρ Airflow = Velocity ⋅ Fan Outlet AreaPlotting Fan Performance Points Plotting Fan Performance Pointsstatic pressure 2.0 in. H2OFan Performance Curve static pressureairflow airflowFan Speed Input Power Fan SurgeFan Surge Line Percent of Wide-OpenAirflowTabular Performance Data fan’s speed and input power requirementPp” -p” g EGSystem Resistance System ResistanceSystem Resistance Curve Static PressureAirflow Static PressureFan - System Interaction System Resistance CurveFan - System Interaction Higher System Resistance Lower System ResistancePower Out Static Efficiency SE = Power In SE = Constant ⋅ Input PowerStatic Efficiency Airflow ⋅ Static Pressure3,500 cfm ⋅ 2.0 in. H2O = 55%1.65 m3/s ⋅ 491 Pa ⋅ 1.5 kWConstant-VolumeSystem design systemresistance curve pressureVariable-PitchVaneaxial Fan g FHvariable-pitch blades total pressure surge region85% 80% 70% airflowtotal pressure surge regiong FM anglperiod two Centrifugal FanAir Conditioning Fans g FNForward Curved Fan Forward Curved Fancwt ux r2 - PM2 up” PM up” r-” -t cwt rForward Curved Fan static efficiency50 to 65% applicationBackward Inclined Fan FC vs. BI Fans forward curvedbackward inclined Backward Inclined FanBackward Inclined Fan cwt p“xrpBackward Curved Fan Airfoil Fanbackward inclined backward curvedPlug or Plenum Fan Airfoil Fanstatic efficiency 80 to 86%Vaneaxial Fan straightening vanes fan wheel or impellerg HF Vaneaxial Fan Variable-PitchVaneaxial Fanapplication static efficiencysurge region pressureairflow g HIFan Selection Forward curved FCBackward inclined BI or airfoil AF Vaneaxialperiod three VAV SystemAir Conditioning Fans K 9e“5Riding the Fan Curve “Riding the Fan Curve”VAV System S” p eKeForward Curved Centrifugal Fan Fan Control Loop VAV System Modulation Curve Methods of Fan Capacity Control Discharge DampersDischarge dampers Inlet vanes Fan-speedcontrol 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-SpeedControlVariable-PitchBlade Control p“-”vKeg MF variable-pitch bladescwt t e eK/ up”Fan Control Comparison powerdischarge design airflowperiod four Air Conditioning Fansg MI System Static-PressureControl controllersensor VAV supplyterminal units fanOptimized Static-PressureControl System Effect System EffectAcoustics Acoustical Guidelines Minimize system effectsAvoid rectangular sound traps, if possible Use adequate vibration isolationEffect of Actual Conditions 5 Poweractual = Air Density Ratio ⋅ Powerstandard1 Air Density Ratio = DensityactualEquipment Certification Standards Purposeperiod five Review-PeriodOneAir Conditioning Fans Review-PeriodTwo Review-PeriodThreeaxial centrifugal “Riding the fan curve” Discharge dampersReview-PeriodFour Application considerationsg NO 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 yvi8yveCDF8gr gAc8hrf8yvi8yveCDF8DCPP8grEOCF8P8EOI FLCC t e