Re: [EnergyPlus_Support] Energy Plus, problems with inside view factors

["UCSB Building ucsbsim@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

Thanks Brent!

I wanted to use this to model explain to view factor calculations to students and I was hoping for something more interesting than a cube to tell the story (without having to do hand calculations) but it looks like I'll go back to a cube for discussion.

Thanks again.

On Mon, Jan 26, 2015 at 9:55 AM, 'Brent Griffith' brent.griffith@xxxxxxxxxxxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

This is a clear example of why EnergyPlus cannot really claim to support non-convex zones.  That zone is not simple enough and this is what the simple, orientation-based algorithm produces.  If you want to pre-calculate more accurate view factors off line, you can input them using the ZoneProperty:UserViewFactors:bySurfaceName object.

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Monday, January 26, 2015 10:40 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Energy Plus, problems with inside view factors [4 Attachments]

 

 

Hello,

 

I wanted to look at view factors for a very simple single room geometry.  I made a simple model and looked at the .bdg file for the view factors.  Some of these don't seem believable to me.  

 

For instance in the attached pdf, the factor for wall 6-5 is pretty significant although they are 90 degrees from each other and not internally facing.  There is a number of other peculiarities that I cannot figure out.  Another example F2-6 is mostly zero, while F2-5 is significant even though wall 5 is farther than 6 and rotated by 90 degrees.

 

I've checked numerous times  to see if my labeling is incorrect on the drawing and in the table but everything seems to check out ok.

 

Any thoughts?

__._,_.___

---

Posted by: UCSB Building <ucsbsim@xxxxxxxxx>

---

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.

Visit Your Group

• New Members 11

• Privacy • Unsubscribe • Terms of Use

__,_._,___