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


asked 2018-01-31 12:09:00 -0500

GONGHJ's avatar

updated 2018-01-31 15:02:39 -0500

I have spikes when running E+ example file 'RefBldgOutPatientNew2004_Chicago.idf'. I think the problem is caused by HVAC sizing. The problem is within outputvariable: 'Whole Building:Facility Total HVAC Electric Demand Power W '

The run data is set to 7/01, timestep is 20, and weather data is 'USA_IL_Chicago-OHare.Intl.AP.725300_TMY3.epw'.

Is there any way of avoiding such spikes?

I am sorry I don't have enough points to post the figures.

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2018-01-31 13:04:47 -0500

updated 2018-02-01 07:04:49 -0500

If you are autosizing, set the averaging window to 1 hour or more (3 time steps). If not autosizing, then the system may be oversized.

  1,                                      !- Heating Sizing Factor
  1,                                      !- Cooling Sizing Factor
  3;                                      !- Timesteps in Averaging Window
edit flag offensive delete link more


thank you very much. It works well when I just run the default design day. But if I use weather data, then there are spikes.

Do you know what would be the potential causation? thanks.

GONGHJ's avatar GONGHJ  ( 2018-05-03 10:09:35 -0500 )edit

Compare the size of the HVAC (see eio or html files for autosizing results) when changing the averaging window from 1 to 3 to 5 and see how this impacts the electricity spikes.

rraustad's avatar rraustad  ( 2018-05-03 10:19:59 -0500 )edit

Thank you very much. By checking the HVAC sizing summary, I found there is only autosized HVAC for the design days. Those spikes appear in the days using weather data. Could you please give me more advice?


GONGHJ's avatar GONGHJ  ( 2018-05-04 14:08:53 -0500 )edit

Plot zone temp and set point and HVAC sensible (or total) capacity then zoom in on one day to see whats happening.

rraustad's avatar rraustad  ( 2018-05-06 20:25:48 -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: 2018-01-31 12:09:00 -0500

Seen: 97 times

Last updated: Feb 01 '18