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[EnergyPlus_Support] AirTerminal:SingleDuct:ParallelPIU:Reheat not cycling



Hi All,

Sorry if this is an obvious question but I haven't managed to get the parallel PIU cycle at night. I got it work on the singleduct terminal as in the example but unsuccessful with the parallel PIU.
Do they work with night cycle?

Thanks

Moana


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "moana" <moana.reynau@...> wrote:
>
> Richard,
> 
> Do you know if PIU parallel fan with electric reheat can utilize cycling fan mode? I've been able to have the singleDuct:VAV:reheat terminal cycle but not the parallel PIU...
> 
> Thanks
> 
> Moana
> 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <RRaustad@> wrote:
> >
> > There is no deadband on Tstat setpoints in E+. If you want the fan to 
> > cycle, set the fan operating mode schedule to 0. This only works for 
> > systems that can utilize cycling fan mode. For example, UnitarySystems, 
> > Furnaces, and some ZoneHVAC equipment.
> > 
> >    AirLoopHVAC:Unitary:Furnace:HeatCool,
> >      CyclingFanSchedule,      !- Supply Air Fan Operating Mode Schedule Name
> > 
> > 
> > On 6/3/2011 2:06 PM, moana wrote:
> > >
> > >
> > > Sorry All,
> > > Disregard my previous message, when i exported the geometry from 
> > > design builder it assigned a schedule to the reporting of the mean air 
> > > temperature which shifted the curve when i was viewing it in the 
> > > Result Viewer.
> > > I had another question though. When using the dualsetpoint thermostat 
> > > is there a way to enter a deadband on the heating and on the cooling 
> > > setpoints? As deadband I mean for example if the heating setpoint is 
> > > 20C, i would like to allow a +/- 1 degree around it so that the fans 
> > > don't run constantly but intermittently rather.
> > >
> > > Thanks
> > >
> > > Moana
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>, "moana" 
> > > <moana.reynau@> wrote:
> > > >
> > > > Hi All,
> > > >
> > > > I'm trying to model a simple VAV system with local reheat (PIU). 
> > > When I set up the availability of the air terminals to - always on - 
> > > The indoor temperature is maintained within the setpoints. The problem 
> > > is that at night the parallel fan runs all the time. When I set up a 
> > > schedule with the fans off at night there is a short swing in 
> > > temperature in the evening below the setpoint (17 deg C). Then the 
> > > temperature goes back to normal.
> > > > I checked the sizing of the heating coils and flow. Entered the 
> > > values back manually and tried to oversize as well (doubles the 
> > > capacity) without any effect.
> > > > I also checked the timestep and bumped it to 30. No change.
> > > > If you check the attached file the problem occurs in the winter 
> > > (there's an example around 4th Dec).
> > > > There's an old post from 06 refering to a similar problem. 
> > > http://tech.groups.yahoo.com/group/EnergyPlus_Support/message/6649
> > > > Not sure if this is still the same.
> > > >
> > > >
> > > > Thanks for your help!
> > > >
> > > > The idf file is in the Files/Problem_submittals folder.
> > > >
> > > >
> > > > Moana
> > > >
> > >
> > > 
> > 
> > -- 
> > 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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