[EnergyPlus_Support] Re: Flow mismatch in radiant system - uploaded file

["e_matta81" <e_matta81@xxxxxxxx>]

Dear support,
after having sent the file to you I tried to understand the reason of
this "flow mismatch".

1. Changing the pump rated pump head power and the rated power
consumption has a direct effect on the number of warnings I obtain.
I tried to analyse the input parameter by parameter but I can't
understand why the simulation ends up still with warnings and
according which calculation.


2. The warning says:
   ** Warning ** Flow mismatch in radiant system--result will be an
energy imbalance--should not get this error
   **   ~~~   ** WaterInjectionRate=-2.53E-003, in Radiant
System=OFFICE_W_0_RADIANT_CEILING

I don't understand if the flow specified in the warning is in m3/s
(like the input) or in kg/s (like the output).
In the first case the error would be very consistent, in the second
one it would be unimportant, compared to the flow in the panels.

Thanks for any suggestion!!






--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "e_matta81" <e_matta81@...>
wrote:
>
> Dear support,
> 
> I uploaded the file "office_flow_mismatch" in the files area.
> Basically this model represents an office building.
> 
> Each zone has radiant system for heating and cooling with pipes
> embedded in the ceiling.
> Beside a ventilation system supplies air flow at 21 C.
> The warning 
> 
> "Flow mismatch in radiant system--result will be an energy
> imbalance--should not get this error
>    **   ~~~   ** WaterInjectionRate=-1.72E-003"
> 
> appears several times and it seems related to a negative value of the
> injection flow of the pump.
> 
> I tried to modify "Volume of the plant loop" in PLANT LOOP, but I
> didn't obtain any improvement.
> 
> 
> Thanks a lot for your help
> 
> 
> 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
> <mjwitte@> wrote:
> >
> > I do not have any suggestions.  Please upload the idf file to the
> yahoo group 
> > files area or send as a zipped file to energyplus-support@
> > 
> > Mike
> > 
> > 
> > On 11 Jan 2008 at 15:31, e_matta81 wrote:
> > 
> > > Hi,
> > > I'm simulating a building with radiant cooling and heating by
> > > LOW_TEMP_RAD_SYST:CONSTANT_FLOW.
> > > 
> > > I can't understand how to solve this problem:
> > > "Flow mismatch in radiant system--result will be an energy
> > > imbalance--should not get this error
> > > WaterInjectionRate=-1.35E-003"
> > > 
> > > I didn't use any autocalculation and any coils, but only purchased
> > > chilled and hot water.
> > > 
> > > It seems that the program calculate a negative flow...
> > > 
> > > Thanks a lot for any help or suggestion!
> > > 
> > > JM
> > > 
> > > 
> > > 
> > > 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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