Re: [EnergyPlus_Support] building on stilts + non-convex surfaces

[Linda Lawrie <linda@xxxxxxxxxxxxxx>]

Yes, your building can be modeled in EnergyPlus.

Yes, outdoors is the proper boundary condition for the floor.

You may get better results, shadowing wise, if you model the extensions
you show as part of the roofs as "overhangs".

You can break your non-convex surface into two -- if it is one of your
end walls, model the top part as a triangle.

At 11:07 AM 12/28/2012, junegomez81 wrote:


> Hi,
>
> I am using Energy+ to analyse the performance of a residential building
> for an assignment, but I am finding a lot of trouble since the building
> is quite 'special'. Besides, I am not familiar with the program, but I
> have to study the effect of natural ventilation on the thermal
> performance of the building and this is the best option I have
> found.
>
> My first concern is the fact that it is a building on stilts, and I don't
> know how to model this. I am doing the following:
>
> In 'Thermal zones and surfaces'
> [008] BuildingSurface: Detailed
> for the Floor, I've set the 'Outside boundary condition' as 'Outdoors'
> instead of 'Ground'.
>
> Would that be a valid approach?
>
> Apart from this, I'm getting the following error one time and
> again:
>
>  ** Severe  ** DetermineShadowingCombinations:
> Surface="OBJ:0004" is a casting surface and is non-convex.
>    **   ~~~   ** ...Shadowing values may be
> inaccurate. Check .shd report file for more surface shading
> details
>
> I've read previous posts regarding this issue and have tried to solve the
> problem following the advices given, but the problem persist.
> I attach an image of the building. Is not possible to analyse this kind
> of geometry in Energy+? I've already simplified the building, and I am
> concerned that if I simplify it even more the results I get might be
> worthless.
>
> I would be really grateful if somebody could give me an answer.
>
> Thank you in advance.
>
> Kind regards,
>
> june

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