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[EnergyPlus_Support] Re: Air volume flow rate - related warning message



I'm getting the same warnings. I'm using a Fan:VariableVolume in combination with a Coil:CoolingDX:SingleSpeed
It is a baseline model according to ASHRAE 90.1-2007 (system 6).
Do you think that replacing the Coil:CoolingDX:SingleSpeed with a Coil:Cooling:DX:TwoStageWithHumidityControlModee would be the solution?
Regards


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" <mjwitte@...> wrote:
>
> Sorry this was not answered sooner.
> 
> Without seeing the input file, it is difficult to guess.  Is everything in the 
> system autosized?  If there is a mix of hard values for some flow rates and 
> autosized values for others, the autosizing routines know nothing of the hard 
> values entered in individual component objects.  They only know of hard flow 
> rates entered in ZONE SIZING and SYSTEM SIZING objects.
> 
> How serious?  That is hard to say.  In this case, the flow rate is only 
> slightly out of range.  But in general, DX equipment is typically designed to 
> operate well inside this range of flows/capacity.  So, if the warnings trip, it 
> usually means something is not entered correctly.
> 
> Mike
> 
> 
> 
> 
> On 21 Aug 2007 at 14:19, krgowri wrote:
> 
> > I am looking for help to understand and resolve this warning message.
> >  In this case, both the capacity and flow rates are autosized. 
> > 
> > How is the air flow rate range determined?  The warning suggests I use
> > a different coil type.  Has anyone experimented with changing the coil
> > type?  How serious is this warning in terms of the simulation results?
> > 
> > ** Warning ** COIL:DX:COOLINGBYPASSFACTOREMPIRICAL "SYS1 DX COOLING
> > COIL" - Air volume flow rate per watt of rated total cooling capacity
> > is out of range at   6.717909491932784E-005 m3/s/W.
> >    **   ~~~   **  Occurrence info=ANCHORAGE AK USA TMY2-26451
> > WMO#=702730, 11/10 11:00 - 11:04
> >    **   ~~~   ** Expected range for VolumeFlowperRatedTotalCapacity=[
> >  2.684000000000000E-005--  6.713000000000000E-005]
> >    **   ~~~   ** Possible causes include inconsistent air flow rates
> > in system components,
> >    **   ~~~   ** or variable air volume [VAV] system using incorrect
> > coil type.
> > 
> > 
> > 
> > 
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> > 
> > The group web site is:
> > http://groups.yahoo.com/group/EnergyPlus_Support/
> > 
> > Attachments are not allowed -- please post any files to the appropriate folder
> > in the Files area of the Support Web Site.
> > 
> > EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the
> > Documentation link and press the "search" button.
> > 
> > Yahoo! Groups Links
> > 
> > 
> > 
> > 
> > 
> 
> 
> ========================================================
> Michael J. Witte, GARD Analytics, Inc.
> EnergyPlus Testing and Support      
> EnergyPlus-Support@...
>



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