energy plus simulation error

Hey All,

Thank you so much for helping with responses so actively.

Currently I was trying to run a simple energy simulation for my building and it is giving me the following errors:

1. The simulation has not run correctly because of this severe error:

** Severe ** GetSurfaceData: Some Outward Facing angles of subsurfaces differ significantly from base surface.

2. The simulation has not run correctly because of this severe error:
** Severe ** Problem in interior solar distribution calculation (CHKBKS)

3. The simulation has not run correctly because of this severe error:
** Severe ** DetermineShadowingCombinations: There are 4 surfaces which are casting surfaces and are non-convex.

I have never seen these errors in the past few months of performing these simulations for the same building and I would be grateful for any help in solving these.

I actually am on a time crunch as my review for this project is in 2 days.

I really appreciate all the help.

Thank you,

Amrita Ghosh

Attachments:

e+error.png, 400 KB
New + Existing Structure_divided zones_with windows_energy+solar gain_3rdMay_with shell.gh, 1.5 MB

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Permalink Reply by Chris Mackey on May 2, 2015 at 11:01pm

Hi Amrita,

I think that, from looking at your previous files on the discussions, those errors have always been there. It is just that a recent update of the run simulation component on the github now outputs these severe errors as comments on the component so that you are more aware of them (before you had to go searching through the "report" output).

Even though E+ labels these errors as sever, the truth is that they are really not that bad and they only appear because Honeybee, by default, runs simulations with full interior and exterior solar distribution calculations. You get those errors because the interior solar distribution calculation does not like "L"- shaped zones (or concave zones to be more specific) because when it traces a sun vector from the floor of the room to the sky, there is the potential for more than one wall of the room to be intersected, thereby messing up the calculation.

What this means is that your overall heating/cooling values and temperature values of your zones are still really accurate. However, individual surface temperatures will not be accurate because the calculation of solar energy among them is not correct. If you want to get correct surface temperatures, you will have to break up your "L"-shaped surfaces into multiple surfaces or break up "L"-shaped zones zones into two zones with an air wall between them.

I hope that this clarifies.

-Chris

Permalink Reply by Amrita Ghosh on May 2, 2015 at 11:40pm

Hi Chris,

Thank you so much. This makes it so much clearer. Right now we are only calculating building energy consumption but this helps in understanding why it messes up calculation for such shapes.

Thank you again,

Amrita

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