Re: [EnergyPlus_Support] Re: non-convex warning

Tilak, read the I/O reference guide at "Solar Distribution": http://bigladdersoftware.com/epx/docs/8-4/input-output-reference/group-simulation-parameters.html#field-solar-distribution

Your solar distribution is set to FullExterior, which means it'll only calculate shadow patterns on exterior surfaces, and assumes that all beams of solar radiation entering the zone just fall on the floor. So it doesn't care that your zone in concave, just that the roof is not convex. So yes, breaking up the roof into rectangles or triangles will fix this warning.

As far as the size of your zone, I'd say it really depends what you're trying to achieve here. You just have to remember that in E+ the zone is considered to be fully "mixed": whether you're in the center or a corner of the zone, the temperature is the same. It'll represent only one node for the calculation.

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr

2015-12-03 12:25 GMT+01:00 fati tilak fati_tilak@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:

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oh... the bulkhead!!! Thank you.Â
Â Is it Â enough to cut the roofs into convex shapes without divining zone into smaller zones .Â
Also, Based on the previous reply, my zone is too big. Does it cause any problems? I mean: should I divide the zone to smaller zones

Thank you very much for your time and help.
TilakÂ

On Thursday, December 3, 2015 2:23 PM, "Julien Marrec julien.marrec@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

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The difference between your two models is that the "big roof" is a "receiving surface" (it'll get shaded but the bulkhead zone) only in one case, the one where you get the warnings

The warning is pretty clear on that point too: "DetermineShadowingCombinations: Surface="OBJ:0159" is a receiving surface and is non-convex"

No bulkhead, no warnings:

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Bulkhead = warning

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--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr

2015-12-03 11:23 GMT+01:00 fati_tilak@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:

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corresponding to the previous Email... Attached you can find another IDF file. This model has also 2 zone Â with approximately same plan, floor area and zone volume. from the point of non-convex definition, the roofs are not convex. However, when I run this fileÂ , I do not receive any non-convex warning .Â
if the main cause of "non-convex warning" is related to the shape of the roof, why I am not reported about this problem while I run this IDF file.
Would you please consider this file.Â

.. Um... Is it very serous to fix the non-convex warning?Â I mean...., Â can I rely of the result of the model simulation if I do not fix this warning? Â

Or, Is it Â enough to cut the roofs into convex shape ( not the zone)?Â
Thank you so much.

Best,

Tilak