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Re: [EnergyPlus_Support] ideal cooling + constVolSystem
I tried turning off the air loop system and the max iteration errors went away.
So the problem is in that part of the simulation.
I see that most (or all) of the air loop components are autosized, and all but
one of the DIRECT AIR units has a hard number for flow rate (not autosized).
The autosizing algorithm will not see the flow rates in the DIRECT AIR objects.
If you want to force a certain flow rate for a terminal unit, you must enter
this in the ZONE SIZING object. In the ZONE SIZING objects, add these fields:
ZONE SIZING,
flow/zone, !- cooling design air flow method
0.7, !- cooling design air flow rate {m3/s}
For each zone, specify the desired flow rate here. This should result in an
air loop where all the flow rates are consistent and it should get rid of the
max iteration errors.
Mike
On 20 Jun 2007 at 10:28, Sebastian Dietz wrote:
> Hello Mike,
> please disregard my last mail.
> The iteration warnings still appear. I changed the priorities in the
> ZONE EQUIPMENT LIST Objects, but it didn´t solve the Problem.
> Furthermore I increased the number of maximum iterations with no result.
> It would be nice, if you have another suggestion. I spent a lot of time
> on that problem and I`m stuck.
>
> thanks in advance
> sebastian
>
> Michael J. Witte schrieb:
> > In the ZONE EQUIPMENT LIST objects the "priority" is the order in which the
> > equipment is simulated. Because the impact of the outside air can change the
> > net heating or cooling load required, it should always be simualted first.
> > So, change the heating and cooling priority for the DIRECT AIR units to be 1,
> > and adjust the other equipment prioirities accordingly. This should solve the
> > problem.
> >
> > Mike
> >
> >
> > On 19 Jun 2007 at 10:08, Sebastian Dietz wrote:
> >
> >
> >> Hello everybody
> >>
> >> currently I'm modelling a building with 10 zones. Each zone gets heated by a
> >> basebord and is served with outside air by a constant volume System. Up to
> >> here the system runs quite good. Now I want to model a ideal cooling System
> >> to limit the maximal indoor temperature. Thus I used the Object
> >> "PurchasedAir", in order to provide cool air for each Zone. But I get miximum
> >> iterations Warnings for each timestep. I changed the values for tolerances
> >> with no effect. Does anybody know, how to solve the problem, or is there
> >> another easy way to model an ideal cooling system. For more information I
> >> uploaded my "Typgebaeude.idf" file
> >>
> >> Thanks in advance
> >> Sebastian
> >>
> >> --
> >> Sebastian Dietz
> >> Fraunhofer-Institut for Solare Energiesysteme ISE
> >> Heidenhofstrasse 2, 79110 Freiburg, Germany
> >> Phone: +49 (0) 7 61/ 45 88-51 36
> >> Sebastian.Dietz@xxxxxxxxxxxxxxxxx
> >> http://www.ise.fraunhofer.de
> >> -------------------------------------------
> >>
> >>
> >>
> >> 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
> >
> >
> >
> >
> >
>
>
> --
> Sebastian Dietz
> Fraunhofer-Institut for Solare Energiesysteme ISE
> Heidenhofstrasse 2, 79110 Freiburg, Germany
> Phone: +49 (0) 7 61/ 45 88-51 36
> Sebastian.Dietz@xxxxxxxxxxxxxxxxx
> http://www.ise.fraunhofer.de
> -------------------------------------------
>
>
>
> 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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