Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question
2

Kiva vs F-factor Ground Method

asked 2023-10-26 13:01:19 -0500

apdavis's avatar

updated 2023-10-28 13:53:43 -0500

I've been modeling buildings using the Kiva foundation method with the default Kiva settings and I'm seeing a big difference in the annual heating when the building has cooling versus when there's no cooling. Here I used create typical to make a 1-story 30,000 sqft office building and this graph show the zone temperature of the building's center zone which seems to be where the biggest problem is. Red is with cooling, blue is without cooling. Zone Temperature cooling v no cooling

When I switched the foundation to F-factor I don't seem to get the same problem. This graph shows zone temperature of the building's center zone when modeled with no cooling where blue is Kiva and orange is F-factor. Zone Temperature Kiva v F-factor

I tried running the model in OpenStudio v1.6 based on other posts, but I'm still seeing the same issue. Any ideas what could be causing this?

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
2

answered 2023-10-26 18:50:41 -0500

Have you tried explicitly setting the Initial Indoor Air Temperature input for Kiva?

EnergyPlus did have a bug (fixed in E+ 23.2) where the default value could be calculated incorrectly. Kiva also defaults to 22 C (71.6 F) for unconditioned zones, which can be a really poor assumption for, say, a vented crawlspace or unconditioned basement.

edit flag offensive delete link more

Your Answer

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

Add Answer

Training Workshops

Careers

Question Tools

1 follower

Stats

Asked: 2023-10-26 13:01:19 -0500

Seen: 259 times

Last updated: Oct 30 '23