Transcription of How to Read a Fan Curve
1 How to read a Fan CurveFan curves Three main components CFM Static Pressure Brake 2 4 6 8 1012141618 CFM x 100 PressureFan Curve (Pressure to CFM relationship) 2 4 6 8 1012141618 CFM x 100 Horse PowerBrake Horsepower Curve (CFM to BHP relationship) x 100 Horse PowerTypical Fan Performance 2 4 6 8 101214161820 CFM x 100 PressureConstant Horsepower CurveTypical System Resistance 4681012141618 CFM x 100 PressureSystem Resistance CurveSum of all system components: Ductwork Elbows Transitions Filters Coils Dampers Louvers Building pressurePs = k * CFM2 Pressure Increases with the Square of CFM!
2 Varying System Resistance x 100 Static PressureGoing from Curve A to Curve B is an example of a system that a damper closes or filters get BCurve AIncreasing Resistance to x 100 Horse PowerOperating PointFan Performance CurveBrake Horsepower CurveSystem Resistance CurveOperating 2 4 6 8 1012141618 CFM x 100 Horse PowerFan Performance CurveBrake Horsepower CurveSystem Resistance CurveOperating PointReading BHp x 100 Pressure700 RPM350 RPMO perating Pointat 700 RPMO perating Pointat 350 RPMV arying Operating PointsLarge change in Ps Small change in CFMS mall change in Ps Large change in CFMCFMPsSelecting Point of OperationPsOperating PointOptimum RangeUnstableCFMS electing Point of Operatio
