[EnergyPlus_Support] Re: Warning: "Air volume flow rate per watt ... is out of range .."

["JV Dirkes II" <jvd2pe@xxxxxxx>]

Dear E+ Forum,

I am looking at this warning again, trying to understand it... and
failing to do so.

In short:
The warning occurs over 3700 times in 3 Design days; this seems excessive!
The warning appears to occur multiple times in a single minute (I get
multiple warning messages for the exact same time, coil and design
day. I have specified 4 timesteps per hour, but the warnings refer to
minutes that are NOT timesteps.)
The "air volume per watt" is an acceptable value at the timestep (It
is within the acceptable range noted in the warning.)

Since this warning occurs for a non-timestep minute, something seems
to be going on in the background.  In addition, there are no other
errors or warnings which suggest a cause for this one.

Thanks in advance.


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Don Shirey <shirey@...> wrote:
>
> The warning can be an indication of very low supply air flow rate 
> compared to the coil's cooling capacity.... and very low outdoor air 
> temperatures may also be contributing.
> 
> Find the autosized air flow rate and cooling coil capacity in the .eio 
> file ... and then look at the COIL:DX:COOLINGBypassFactorEmpirical 
> documentation in the IO Reference and Engineering Reference for how
that 
> coil model works and how the flow rate/capacity values are used.
> 
> 
> JV Dirkes II wrote:
> > Dear E+ Forum,
> >
> > The Air handler for a current E+ model (v2.2) has a
> > COIL:DX:COOLINGBypassFactorEmpirical cooling coil and a hot water
> > heating coil.  The model runs, but has hundreds of instances of this
> > warning or "Full load outlet temperature indicates a possibility of
> > frost/freeze...", which appears to have a similar cause. All
> > capacities are autosized and I am simulating only 3 Design Days with 4
> > timesteps per hour (so the hundreds of warnings seem to be too many!)
> >
> > Will someone help me understand the cause of the error and how to
> > resolve it?  Thank you!
> >
> >
> > ------------------------------------
> >
> > 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
> >
> >
> >
>



------------------------------------

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