Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question

negative impact of demand control ventilation

asked 2016-04-21 00:00:51 -0500

elvin gravatar image

updated 2021-05-07 09:44:45 -0500

Hello, I'm trying to model demand control ventilation in open studio but because CO2 levels and system outdoor air method cannot be adjusted, the outputs are not how they re expected. On the other hand, I tried to add those missing inputs in energy plus via idk editor but still dcv does not provide any energy savings. Even though fan consumption is decreased after implementing dcv, somehow heat rejection and pump energy consumption goes up so in total there is more electricity consumption observed. Is there a way to debug this problem?

Thank you Elvin

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2016-04-21 16:26:52 -0500

First, you can enable DCV in OpenStudio:

  1. On the AirLoop, click the "Control" button at the top of the screen.
  2. Click the Demand Control Ventilation switch to "On." (In E+, this corresponds to setting the Controller:MechanicalVentilation field DemandControlVentilation to Yes)
  3. On the AirLoop, click the "Layout" button at the top of the screen.
  4. Click on the OutdoorAir System
  5. Set the 'Minimum Outdoor Air Flow Rate' in the Controller:OutdoorAir to 0. Otherwise the DCV won't be able to drop the flow rate.

For debugging, I suggest requesting detailed timeseries outputs and graphing them in ResultsViewer.

edit flag offensive delete link more


Yes sure I already did that but what i mean its not possible to make the system control air flow rate (proportion flow rate) by considering occupancy schedule and CO2 levels. I actually found out that demand control ventilation saves when its used with economizer. Especially with differential enthalpy type for climate region like 3A.

elvin gravatar image elvin  ( 2016-04-21 16:36:34 -0500 )edit

Should be possible using the SDK to change the System Outdoor Air Method in the Controller:MechanicalVentilation object with the setSystemOutdoorAirMethod ...method

Eric Ringold gravatar image Eric Ringold  ( 2016-04-21 16:53:53 -0500 )edit

This is an old thread - but it was exactly what I needed (I think). Long story - E+v8.5 - been trying to add DCV as an ECM to a model, have the controller:ventilation and controller:outside air etc....all the parts were there - but not OA turn down. Been scouring the E+ documentation @ BigLadder...nothing. Then I found this - which pointed out on the Controller:MechnicalVentilation object I had Min and max airflow both ''autosized"....min=max=no turn down (derp).....who do we have to bug to get this little detail added to the E+ documentation?? Thank you!!

dradair gravatar image dradair  ( 2016-10-26 19:01:35 -0500 )edit

I tried the DCV in two different OS/E+ files. I can now see the Output:Variable,*,Air System Outdoor Air Mass Flow Rate,Hourly; changing when I use the DCV option.

Alex Vlachokostas gravatar image Alex Vlachokostas  ( 2017-02-01 15:54:16 -0500 )edit

How do I go about accessing the 'setSystemOutdoorAirMethod' from OpenStudio? Is it possible? If now how can I consider occupancy schedules and CO2 levels?

tomaleach gravatar image tomaleach  ( 2017-02-28 13:33:39 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools

1 follower


Asked: 2016-04-21 00:00:51 -0500

Seen: 394 times

Last updated: Apr 21 '16