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Re: [EnergyPlus_Support] Set point not met



The sizing routines will size the reheat coils to be large enough to raise the 
full flow rate from the cooling supply temperature to the heating supply 
temperature.  For a system like this, the reheat coils will tend to be 
significantly oversized and the entire hot water plant will also be oversized.  
I would suggest lowering the design heating supply temperature in the zone 
sizing objects for zones that will not require heating.  

Mike


On 24 Nov 2005, at 0:10, Emanuel Sá wrote:

> Hi
> 
> Thanks, that worked just fine!!
> 
> I have one other problem.
> In this building that i'm simulating, there are high internal gains, so it
> requires cooling all year. It also requires humidity control so I instaled a
> terminal reheat coil and a boiler. In the design file (eio) says that the design
> hot water flow is " Design Boiler Water Flow Rate [m3/s],  0.31956E-02" which is
> 3.1956 kg/s aprox. however, in the spreadsheet I see that the demand bypass flow
> is never less than 3.17 kg/s !!! so, I dont understand how this design flow rate
> is possible! the gas consuming is almost equal to the chiller electric
> consuming!! Am'I doing anything wrong?
> 
> Thank you very much!
> 
> 
> ----- Original Message ----- 
> From: "Michael J. Witte" <mjwitte@xxxxxxxx>
> To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
> Sent: Wednesday, November 23, 2005 9:26 PM
> Subject: Re: [EnergyPlus_Support] Set point not met
> 
> 
> > Yes, a properly autosized system should be able to meet the zone setpoints on
> > the design days.  Things to check:
> >
> > 1.  If using coil:water:cooling, we have recently learned that it may not size
> > properly if the design delta humidity ratio is less than 0.01.  Check the
> > component sizing report for the cooling coil(s) in the eio output file. If the
> > design entering minus leaving humidity ratio is smaller than 0.01, change to
> > using the COIL:Water:DetailedFlatCooling
> >
> > 2.  Is the supply air temperature setpoint being met?  The design supply air
> > temperatures in the sizing objects must match the setpoint controls in the
> > simulation.
> >
> > 3.  Are the chillled water/hot water supply setpoints being met?  Again, the
> > setpoint controls must match the specifications in the plant sizing objects.
> >
> > 4.  Also check availability schedules.
> >
> > Mike
> >
> >
> > On 23 Nov 2005, at 5:07, dust_broom wrote:
> >
> >> Dear all.
> >>
> >> I've simulated a cooling system for a 4 zone bilding using a chiller a
> >> boiler(for reheat), coils and a single duct . Every component was
> >> suposed to be autosized. So I did the autosize. But than, in the
> >> results I saw that only one of the four zones had its temperature
> >> correct. the others were floating arround 6 degrees. Even in the
> >> design day simulation some zones were too hot. shouldn't the design
> >> day be sizing those equipments in order to maintain the zone
> >> temperatura as specified? Am I doing anything wrong?
> >>
> >> Thank you, Emanuel
> >>
> >>
> >>
> >>
> >>
> >>
> >> 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.idf and press the
> >> "search" button.
> >>
> >> Yahoo! Groups Links
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support
> > EnergyPlus-Support@xxxxxxxx
> >
> >
> >
> >
> >
> > 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.idf and press the
> > "search" button.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> > 
> 
> 
> 
> 
> 
> 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.idf 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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