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[EnergyPlus_Support] Re: Fan Power Pressures and Efficiencies - Are the calculations based on Pstat or Pt
That is a very circular answere that does not at all answere the question. I've looked the documentation and it is not clear which is the input, static pressure rise "across the fan" or dynamic pressure rise.
The definition of "Supply Fan Delta Pressure" is not clear!
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <RRaustad@...> wrote:
>
> The value you enter in the fan object is used by E+ in the calculations:
> the equations are described in the Engineering Reference. The detlaP
> used in those equations are the value you enter in the fan object (in
> this case 600 Pa)
>
> Fan:OnOff,
> Supply Fan 1, !- Name
> FanAndCoilAvailSched, !- Availability Schedule Name
> 0.7, !- Fan Efficiency
> 600.0, !- Pressure Rise {Pa}
>
>
> jeannieboef wrote:
> >
> > Correct, however still not clear which is used as user input and which
> > is calculated by e+.
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > <RRaustad@> wrote:
> > >
> > > Total pressure.
> > >
> > > Ptotal = Pstatic + Pdynamic
> > > Ptotal = Pstatic + 1/2 * rhoV^2
> > >
> > >
> > > jeannieboef wrote:
> > > >
> > > > Are the calculations based on total pressure or static pressure rise?
> > > >
> > > > Field: Supply Fan Total Efficiency
> > > > Enter the total efficiency of the supply fan. This is the ratio of
> > the
> > > > power delivered to the air to
> > > > the electrical input power at maximum flow. This is also the product
> > > > of the fan motor
> > > > efficiency and fan (impeller) efficiency. The motor efficiency is the
> > > > power delivered to the
> > > > shaft divided by the electrical power input to the motor. The fan
> > > > efficiency is the power
> > > > delivered to the air divided by the shaft power. The power delivered
> > > > to the fluid is the mass
> > > > flow rate of the air multiplied by the pressure rise divided by the
> > > > air density. Must be greater
> > > > than 0 and less than or equal to 1. The default is 0.7.
> > > >
> > > > Field: Supply Fan Delta Pressure
> > > > Enter the pressure rise in Pa at full flow and standard conditions.
> > > > Standard conditions are
> > > > considered 20o C at sea level, 101325 Pa. The default is 1000 Pa.
> > > >
> > > >
> > >
> > > --
> > > Richard A. Raustad
> > > Senior Research Engineer
> > > Florida Solar Energy Center
> > > University of Central Florida
> > > 1679 Clearlake Road
> > > Cocoa, FL 32922-5703
> > > Phone: (321) 638-1454
> > > Fax: (321) 638-1439 or 1010
> > > Visit our web site at: http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>
> > >
> > > UCF - From Promise to Prominence: Celebrating 40 Years
> > >
> >
> >
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
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