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

["Michael J. Witte" <mjwitte@xxxxxxxx>]

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@xxxxxxxx





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