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[EnergyPlus_Support] Re: Effects of Cooling Setpoint Change
Thank you very much for your feedback, I am still confused however as
to why the consumption of the pump is increasing as a result of the
cooling set point change. I have defined my building using the Compact
HVAC objects an have fixed all of the "autosize" components to hard
values as such my expectation would be that the consumption of the
pumps would either remain constant or be reduced due to the lessened
need for chiller operation.
Any thoughts?
Eric
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
<mjwitte@...> wrote:
>
> The system has a fixed cooling supply air temperature setpoint. For
the
> constant volume case, the system is always cooling the same flow
rate of air to
> the same supply temperature, no matter what the zone setpoints are.
So, the
> result of little change is chiller load is to be expected. If there
are no
> reheat coils (as the uploaded files show) then the zone temperatures
will not
> be controlled at all. It is not clear what you are expecting the
constant
> volume system to do.
>
> Mike
>
>
> On 14 Dec 2007 at 21:10, eric.mcmaster wrote:
>
> > Hello,
> >
> > I have been attempting to model the effects of changing the cooling
> > set point of a given building, and up to now I have been getting some
> > unusual results. The building is a Constant air volume system
> > (Turndown Ratio = 1.0) which has been defined using the COMPACT:HVAC
> > objects. To model the cooling set point I altered the values within
> > the the cooling set point compact schedules.
> > When the change is implemented only 2 aspects of the energy
> > consumption are affected. First the chiller load (Monthly) is very
> > slightly reduced, and second the Pump load experiences a drastic
> > increase in consumption ~15%. What could be the possible reasons for
> > this increase in the pump load?
> >
> > Also, I have noticed that when a turndown ratio is incorporated into
> > the model, the consumption of the fans within the building are reduced
> > and the chiller consumption also experiences a greater reduction.
> > which leads be to belive that there may be an error in the way i am
> > modelling my building.
> >
> > I will attempt to upload two .idf files for review.
> >
> > Thank you in advance for any advice you may have.
> >
> > Eric
> >
> >
> >
> > 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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