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NREL / EnergyPlus

EnergyPlus™ is a whole building energy simulation program that engineers, architects, and researchers use to model both energy consumption and water use in buildings.
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AirLoopHVAC:OutdoorAirSystem does not control a second heating coil #6934

Open rmcclung opened 6 years ago

rmcclung commented 6 years ago

I'm modelling a building with a central outdoor air handling unit serving VAV system on each floor of a building. The central OA AHU has supply and return fans, heat exchanger, preheat coil for defrost, a cooling coil for cooling and dehumidification, a heating coil, and a humidifier. Since EPlus doesn't support one AHU serving another AHU, I've modelled seperate VAV systems that each have all the central AHU equipment in the outdoor air system, with some EMS to set setpoint temperatures and fan powers.

The issue is that both the preheat heat and heating coils in the outdoor air system are water coils, and when both are used, only the preheat coil is being controlled to meet it's setpoint. While the heating coil has the correct set point set, it is not turning on to meet it. If I remove the preheat coil, the heating coil then works.

I tried swapping the order in the AirloopHVAC controllers list around, and that had no effect. I also tried changing the preheat coil to a gas coil and the file crashes for no obvious reason.

In the attached file CAHU-B1 and CAHU-1 have the preheat coil removed, and the heating coil is operating as intended, and the other CAHUs have both preheat and heating, and while preheat works, the heating coil is staying off despite being below the setpoint temperature.

v 8.9 OA Heating Coils.zip

YanfeiNREL commented 5 years ago

@rmcclung Your input file (IDF) appears having some issue. I tried to run your IDF file, and it will freeze there. Please check your idf file and send me an updated IDF. Please see the attachment for error details. EPTEMP-00000001.zip

rmcclung commented 5 years ago

It runs on my computer, it does have the 8.9 bug, where because there is a schedule referencing a file, it looks in the command window like it isn't running when in fact it is. It takes about 8 minutes to run one day.

YanfeiNREL commented 4 years ago

@rmcclung . Would you please send me an idf can be open by EP-Launch? I couldn't open your idf file, as i got errors from Line number 338372 to 338380. It looks like there is some issue with the branch or branchlist. I see it has more than 250 lines for the branchlist, which is also the error coming from. I need to look at your IDF details to understand the issue.

rmcclung commented 4 years ago

@YanfeiNREL The attached idd file (saved as .txt) with extended fields should help Energy+ - Copy.txt

YanfeiNREL commented 4 years ago

@rmcclung I replaced my idd file with yours, and i still can't open your IDF from EP-launch (version V8.9). The errors i got: ''' Too many fields for object: ElectricLoadCenter:Generators, Line Number 346918. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346919. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346920. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346921. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346922. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346923 Too many fields for object: ElectricLoadCenter:Generators, Line Number 346924. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346925. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346926. Too many fields for object: ElectricLoadCenter:Generators, Line Number 346927.

'''

rmcclung commented 4 years ago

Energy+ - Copy.txt @YanfeiNREL Try again, I got a new computer and hadn't gone back to expand the lesser used fields in the old idd

YanfeiNREL commented 4 years ago

@rmcclung Thanks a lot! I can open the IDF now.