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[EnergyPlus_Support] Re: Air volume flow rate - related warning message
Thank you, Jim. On the contrary, in my case the outdoor air is 0%, because in the design model AHUs are used only to dehumidify, in order to avoid condensation on the cooled floors (outdoor air is provided through windows). I think I will use the Coil:Cooling:DX:TwoStageWithHumidityControlMode and I'll work on the performance curves and on the dehumification control.
With Regards
Francesco Passerini
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Jim Dirkes <jim@...> wrote:
>
> Francesco,
> Take a look at Bereket's post on Sunday. I agree completely with him - in my opinion, these warnings are not completely solvable. I've gotten millions of those warnings for a single simulation! As a result of my excellent talent for generating these warnings :), I have become better at minimizing them, but not eliminating them.
> I believe that the E+ developers are working on an improved version of a multi-speed or variable speed DX coil for the next release which may help a lot. Most of my problems occur for 100% outdoor air applications. Since the actual equipment for those applications are almost always multi- or variable speed, I'm hoping for some relief from those pesky warnings!
>
> James V Dirkes II, PE, BEMP, LEED AP
> www.buildingperformanceteam.com<http://www.buildingperformanceteam.com/>
> Energy Analysis, Commissioning & Training Services
> 1631 Acacia Drive, Grand Rapids, MI 49504 USA
> 616 450 8653
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of FrancescoP
> Sent: Monday, April 29, 2013 9:26 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [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<mailto:EnergyPlus_Support%40yahoogroups.com>, "Michael J. Witte" <mjwitte@<mailto: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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