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Re: [EnergyPlus_Support] dualsetpoint deadband

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.

    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.



--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "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

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