Re: [EnergyPlus_Support] Re: A zone setpoint control anomaly with ‘dual setpoint with deadband'

["Michael J. Witte" <mjwitte@xxxxxxxx>]

 If this is a constant volume system, you can avoid this problem by using the 
single heating cooling setpoint control type.

Mike


On 30 Mar 2006 at 19:15, Elmer Morrissey wrote:

> Hi Fred,
> 
> After checking the EIO file, thats what it seems to be, there is no 
> cooling load in Zone B during the summer design day.
> 
> Thanks for that.
> 
> -Elmer
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, fred buhl <wfbuhl@...> 
> wrote:
> >
> > Elmer,
> > 
> > One thing that happens when you have the 2 setpoints is that the 
> program
> > may be calculating a cooling load for 1 or more zones in the 
> summer. If that
> > happens, the system will be looking at 23 degrees, not 20. So it 
> will 
> > reheat the air
> > to 23C (assuming the air coming in is less than 23), rather than 
> heating 
> > to 20. In
> > the soon-to-be-released version we have attempted to eliminate 
> this 
> > behavior - the
> > system will only reheat to the lowest setpoint temperature.
> > 
> > Fred Buhl
> > 
> > Elmer Morrissey wrote:
> > 
> > >Hello all,
> > >
> > >I would like to know the significance of using `dual setpoint with
> > >deadband' with a system that does not have a cooling coil. I was 
> using
> > >this control for my zone thermostat but I noticed an anomaly. My
> > >system contains an economizer, supply fan, heating coil and 
> terminal
> > >reheat coils. 
> > >
> > >The heating setpoints are set to 20C. The cooling setpoints are 
> set to
> > >23C.
> > >
> > >I was under the impression that since the system is only heating 
> the
> > >air (and letting hot air through without any additional tempering 
> if
> > >OA temps are too high), then zone temps would be kept at 20C year 
> round.
> > >
> > >The system itself is supplying air to three zones. If I run the
> > >simulation, all system functions seem to work fine except for an
> > >anomaly in the zone temps. During the winter: the zones are kept 
> at
> > >20C. However, during the summer: Zone A and Zone C are kept at 23C
> > >while Zone B is kept at 20C. All three zones have been set up the 
> same.
> > >
> > >Can anyone help me in trying to figure out why this is happening? 
> > >
> > >Kind regards
> > >
> > >-Elmer
> > >
> > >
> > >
> > >
> > >
> > >
> > >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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