[EnergyPlus_Support] Re: Warning: Branch flow rates out of bounds

["anarui.oliveira" <anarui.oliveira@xxxxxxxxx>]

Thank you.
Indeed, that was also my first thought, but I checked and, exactly 
because of that, I had already selected intermittent operation mode; 
my guess was that, even in intermittent mode, once the pump turns on 
for the first time in the year, the heat losses from the pump seem 
sufficient to keep the chiller running even when cooling loads fall 
to zero, and in turn the fact that the chiller is working forces the 
pump to keep working, in a vicious cycle. I say this because, until 
the first yearly cooling load appears, the pump is off, but after 
that (in intermittent mode) it stays on for the rest of the year, 
even though I only have temperature control during daytime and 
weekdays (except for a zone with a PTAC, but I don't think implies 
with the chilled water loop...).
Ana.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Edwin Lee" 
<leeed2001@...> wrote:
>
> From what I read, it looks like you are trying to get the pumps to 
turn off
> when not needed.  When you specify pumps in the input file, there 
are two
> control options:  Continuous and Intermittent. For continuous, the 
pumps
> will run always.  If the pump is variable speed, it will run at the 
minimum
> level when not needed.  For intermittent, the pumps will only run 
when
> needed.  I'm not completely sure if this is part of your problem or 
not, but
> I thought I would offer the info anyway.
> 
> Edwin
> 
> On Wed, Apr 23, 2008 at 12:35 AM, mingming_zuo <mingming_zuo@...>
> wrote:
> 
> >   Hi,I think energyplus will automatically shut down chillers 
when no
> > cooling load is posed on the CHW loop,my experience with CHW loop 
in
> > EnergyPlus is that ,if the pump is scheduled to run in some time
> > while not in other times,the pump will continuousely run in its
> > cheduled time rather than run just when there is cooling load. So 
one
> > tip to overcome this is to place pumps in series with chillers, 
and
> > set chillers with active mode and pumps with passive mode. With 
these
> > settings, the pumps will be forced to run in consistent with
> > chiller's operation status.
> >
> > Zuo
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<EnergyPlus_Support%
40yahoogroups.com>,
> > "anarui.oliveira"
> > <anarui.oliveira@> wrote:
> > >
> > > Hi all.
> > >
> > > Because Chiller and Boiler components don't have scheduled
> > > availablity control options, and because, due to components heat
> > > losses, the chiller is called to work even if no cooling coil is
> > > asking, I tried to force it off by scheduling off the pumps (in
> > > Heating and cooling water loops).
> > > When I did this, I got several errors like:
> > >
> > > "PlantFlowResolver: Branch flow rates out of bounds, for Plant
> > > Loop=COOLING LOOP CHILLED WATER LOOP, Branch=45368 COOLING COIL 
CHW
> > > BRANCH"
> > >
> > > but the simulation results seem to coherent, including that 
pumps
> > and
> > > chiller are not working when I didn't want them to.
> > >
> > > Can I ignore these warnings or does it really affect the 
simulation?
> > > Is there a more correct way to ensure the chiller isn't just
> > turning
> > > on because of the pump heat losses?
> > >
> > > Regards,
> > > Ana Rui.
> > >
> >
> >  
> >
> 
> 
> [Non-text portions of this message have been removed]
>



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