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Re: [EnergyPlus_Support] Re: Zone will not reach setpoint
You might also consider using the main air loop heating coil to pick up
more of the load. Why did you choose to heat the air to 12.8C in the
main air loop during the winter design day?
Richard Raustad wrote:
>
> Change your "Central heating design supply air temperature (C)" to match
> what is entering the zone terminal unit heating coil. In this case it is
> 12.78 C. The zone now maintains 18-20C.
>
> SYSTEM SIZING,
> AirLoop_AH1, !- name of an AIR PRIMARY LOOP object
> sensible, !- type of load to size on
> Autosize, !- Design (minimum) outside air volumetric
> flow rate {m3/s}
> 1, !- minimum system air flow ratio
> 4.44, !- Preheat design temperature {C}
> 0, !- Preheat design humidity ratio
> {kg-H2O/kg-air}
> 12.78, !- Precool design temperature {C}
> 0.0087, !- Precool design humidity ratio
> {kg-H2O/kg-air}
> 12.78, !- Central cooling design supply air
> temperature {C}
> 12.78, !- Central heating design supply air
> temperature {C} <--------
> coincident, !- Sizing Option
> no, !- Cooling 100% Outside Air
> no, !- Heating 100% Outside Air
> 0.0087, !- Central cooling design supply air
> humidity ratio {kg-H2O/kg-air}
> 0, !- Central heating design supply air
> humidity ratio {kg-H2O/kg-air}
> design day, !- cooling design air flow method
> , !- cooling design air flow rate {m3/s}
> design day, !- heating design air flow method
> ; !- heating design air flow rate {m3/s}
>
> JV Dirkes II wrote:
> >
> > Dear E+ Forum,
> >
> > I've tried using V2.2.026, since that version addresses a known reheat
> > problem, but the model still reflects the problems noted in my last
> post.
> >
> > Can anyone help?
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "JV Dirkes II"
> <jvd2pe@...>
> > wrote:
> > >
> > > Dear E+ Forum,
> > >
> > > I am still hoping for some help with this problem. I've added report
> > > variables, tried different settings, double and triple checked all th
> > > input, and still cannot get the zone to warm up.
> > >
> > > Thanks in advance.
> > >
> > > p.s., The uploaded file is called "ZoneTooCold.zip"
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "JV Dirkes II" <jvd2pe@>
> > > wrote:
> > > >
> > > > Dear E+ Forum,
> > > >
> > > > My current model includes a variable volume air handler and VAV
> boxes
> > > > with reheat coils. The zone which represent 90% of the building
> never
> > > > reaches its setpoint on the Winter Design Day.
> > > >
> > > > Per report variables, the air handler has proper temperature heating
> > > > hot water (82C) and the discharge temperature is at the expected
> > > > setpoint (12.9C). Air flow is autosized.
> > > >
> > > > The zone reheat coil is also autosized and has the same heating hot
> > > > water temperature as the air handler. Per report variables, the
> > > > reheat coil has water flow and is using energy, but only heats the
> > > > zone to 5C instead of the setpoint (21.1C).
> > > >
> > > > I've tried manually sizing the reheat coils much larger than the
> load,
> > > > but they continue to use only a small fraction of their capacity and
> > > > the zone stays too cold. Please let me know what might prevent the
> > > > reheat coils from warming the zone properly. Thanks!
> > > >
> > > > p.s., I've uploaded the file in case it will be helpful.
> > > >
> > >
> >
> >
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL 32922-5703
Phone: (321) 638-1454
Fax: (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu
UCF - From Promise to Prominence: Celebrating 40 Years
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