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Trane TRG-TRC013-EN manual System Resistance Curve, Static Pressure, Airflow

Models: TRG-TRC013-EN

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Page 25

System Resistance Curve

g

System Resistance Curve

Static Pressure 2		2
		Airflow 2

Static Pressure 1		Airflow 1

g EM

K

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b	8	 Kx	8 8
b------------------------------------------	-7-	=  Kx----------------------		
	-7-		7
P—								95
								8] j7;B _pl4
b		= 846 x”4 R8		 82666 ru–				8
b	8	= 846 x”4 R8		] ⋅ 	-----------------		---------	= 64=; x”4 R8]
					92;66 ru–
b		= :B7 _p ⋅		 64B: –9		5	 8
b	8	= :B7 _p ⋅		 --------------------------			 = 7;B _p
				 74=; –95			

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Image 25

Trane TRG-TRC013-EN manual System Resistance Curve, Static Pressure, Airflow

Contents

Page BUSINESS REPLY MAIL BUSINESS REPLY MAILTHE TRANE COMPANY Attn Applications Engineering 3600 Pammel Creek Road La Crosse WIResponse Card Comment CardAir Conditioning Fans One of the Equipment SeriesWorldwide Applied Systems Group p e The Trane CompanyA Trane Air Conditioning Clinic Air Conditioning Fans99999999999999999999999999999 caQ3caM6793O axial centrifugal Air Conditioning FansMeasuring Pressure period oneAir Conditioning Fans atmospheric ductpressure pressurefwt” p 2 p ”tvp rp S” r“- 4 jK 7683-- r-“4lcwt Positive Duct PressureR-2 x”rwt are “water gage” wg and “water column” wcduct Inclined Manometerpressure reservoirVelocity Pressure vs. Static Pressure Total PressureVelocity Pressure vs. Static Pressure Velocity Pressure vs. Static Pressureg DC damper fully openVelocity Pressure vs. Static Pressure Measuring Static Pressureg DD g DEMeasuring Total Pressure g DG Fan Performance TestVelocity Pressure Pv = Pt - P s Determining Fan AirflowVelocity V = Constant ⋅ √ Pρ Airflow = Velocity ⋅ Fan Outlet AreaPlotting Fan Performance Points Plotting Fan Performance Pointsstatic pressure 2.0 in. H2Ostatic pressure Fan Performance Curveairflow airflowFan Speed Fan Surge Input PowerPercent of Wide-OpenAirflow Fan Surge Linefan’s speed and input power requirement Tabular Performance DataPp” -p” g EGSystem Resistance System ResistanceStatic Pressure System Resistance CurveAirflow Static PressureSystem Resistance Curve Fan - System InteractionFan - System Interaction Lower System Resistance Higher System ResistanceSE = Constant ⋅ Input Power Power Out Static Efficiency SE = Power InStatic Efficiency Airflow ⋅ Static Pressure= 55% 3,500 cfm ⋅ 2.0 in. H2O1.65 m3/s ⋅ 491 Pa ⋅ 1.5 kWdesign system Constant-VolumeSystemresistance curve pressureg FH Variable-PitchVaneaxial Fanvariable-pitch blades surge region total pressure85% 80% 70% airflowsurge region total pressureg FM anglCentrifugal Fan period twoAir Conditioning Fans g FNForward Curved Fan Forward Curved Fancwt ux r2 - PM2 up” PM up” r-” -t cwt rstatic efficiency Forward Curved Fan50 to 65% applicationBackward Inclined Fan forward curved FC vs. BI Fansbackward inclined Backward Inclined Fancwt p“xrp Backward Inclined FanAirfoil Fan Backward Curved Fanbackward inclined backward curvedAirfoil Fan Plug or Plenum Fanstatic efficiency 80 to 86%straightening vanes fan wheel or impeller Vaneaxial Fang HF Variable-PitchVaneaxial Fan Vaneaxial Fanapplication static efficiencypressure surge regionairflow g HIForward curved FC Fan SelectionBackward inclined BI or airfoil AF VaneaxialVAV System period threeAir Conditioning Fans K 9e“5“Riding the Fan Curve” Riding the Fan CurveVAV System S” p eKeForward Curved Centrifugal Fan Fan Control Loop VAV System Modulation Curve Discharge Dampers Methods of Fan Capacity ControlDischarge dampers Inlet vanes Fan-speedcontrol Variable-pitchblade controlupward. 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-SpeedControlp“-”vKe Variable-PitchBlade Controlg MF variable-pitch bladese eK/ up” cwt tpower Fan Control Comparisondischarge design airflowAir Conditioning Fans period fourg MI controller System Static-PressureControlsensor VAV supplyterminal units fanOptimized Static-PressureControl System Effect System EffectAcoustics Minimize system effects Acoustical GuidelinesAvoid rectangular sound traps, if possible Use adequate vibration isolation5 Poweractual = Air Density Ratio ⋅ Powerstandard Effect of Actual Conditions1 Air Density Ratio = DensityactualPurpose Equipment Certification StandardsReview-PeriodOne period fiveAir Conditioning Fans Review-PeriodThree Review-PeriodTwoaxial centrifugal “Riding the fan curve” Discharge dampersApplication considerations Review-PeriodFourg NO System static-pressurecontrol System effectcp”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 gAc8hrf8yvi8yveCDF8DCPP8gr yvi8yveCDF8grEOCF8P8EOI FLCC t e