[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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



Well, the good news is that the algorithm will work for a cube (check out outputs from 1ZoneUncontrolled)

At 12:30 PM 1/26/2015, UCSB Building ucsbsim@xxxxxxxxx [EnergyPlus_Support] wrote:


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.

Â

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]

Â

 

Hello,

Â

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. Â

Â

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.

Â

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.

Â

Any thoughts?






__._,_.___
Posted by: Linda Lawrie <linda@xxxxxxxxxxxxxx>


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
Yahoo! Groups
• Privacy • Unsubscribe • Terms of Use

__,_._,___