Solar Insolation Analysis Doesn't Work on Curtain Walls?

[Anonymous]

Does the solar insolation analysis tool work with curtain walls?  I'm getting some strange results on a model when trying to do solar insolation analysis directly clicking on the glass (or solid) panels in a curtain wall.  So I created a simple one room model to see if I could re-create the strange problems.  I ran three tests:

1. Solid south wall - the readings say 998 kwh/m2
2. Curtain wall - the readings drop to between 157-270 kwh/m2.  Shouldn't the amount of solar insolation be the same regardless of the material?  To test this further, I ran option 3.
3. Solid wall with curtain wall in front - the readings are still 998 kwh/m2.  The curtain wall is directly in front of the solid wall, and I've added tons of mullions to pseudo-simulate an almost solid louver shading device.  And still the readings are the same.  

So my conclusion is that the solar insolation analysis doesn't "see" curtain wall geometry as shading?  And that it doesn't read the solar insolation on curtain wall panels correctly.  

Please advise.

Cheers and thanks for your help! 

[Mohammad_Asl]

Thanks for diving in and explaining the extra tests you did. What you are experiencing is the limitation that solar analysis only works on masses or "standard" Revit families like roofs, walls, or floors. Curtain walls or custom families and even windows can yield unexpected results (usually close to 0). 

That's part of the reason we put out this disclaimer before you select surfaces for anaylsis. We are hoping to fix this, so you can start doing some of the more rigorous testing it sounds like you're needing to do.

I know this isn't a "solution" per se, but hopefully it helps explain how the tool works.

[Anonymous]

This is a really interesting post. I did similar test, and I was deeply disappointed when realized that the analysis do not recognize any kind of curtain wall/mulluions/louvres/etc.

Below some examples of the building that we are doing.We quickly replace the vertical mullions for walls in order to get a general picture of the solar radiation in the not facade.

Hope this get resolve soon!

[mstein7484]

Hello @Anonymous @Anonymous

Our apologies for the frustration. We will be addressing this ASAP. Thanks for your patience.

Regards,

[Anonymous]

How long before this is resolved?

What would be the recommended way to model vertical shading devices like scrim panels, louvered panels etc. At the moment none of our users want to use the tool because it involves double modelling, a visualization model, and then redoing a simplified analysis model. Perhaps you could write a tool to copy the geometry of any element as a mass to speed things up it it takes longer to code the reality of the situation.

Curtain wall in modern commercial architecture is more prevalent than Revit Basic walls, this feature is vital, CW as both a shadow caster, and a solar receiver.

Thanks

[rds3000]

Hi Mark.

SAR currently does not support analysis on surfaces in families (built in or custom) and groups, so this includes curtain walls.  Also linked model geometry may provide unreliable results as an analysis surface, though they should shade correctly.

I think what you're seeing is not that the shading curtain wall is not shading, but that the analysis of points on the shaded curtain wall is not supported.  if you shade the roof, for example, with the dense curtain wall, you should see a shading effect on the roof.  You should also see shading of the floors inside the building.

To test it, place a regular wall in place of the curtainwall that you are trying to analyze.

If you still see odd results, feel free to send the model, and I'll check it out.

David

[rds3000]

Hi again Mark.

I just ran a test, and I was surprised to discover that curtainwall mullions indeed to not shade properly.  That's unfortunate, and something unique to curtainwalls, from what I see in debug.

I did a workaround using ceiling objects in a vertical array, so I could quickly refactor the depth by editing the parent boundary, and the spacing by editing the number of copies.  For now, this may be your only way of experimenting with mullion design before implementing the design with a formal Revit curtain wall layout.

Attached is my test model and some results.  The bottom ceiling object is the parent, and the array is to 'last'. Note that I found I have to change the number in the array to 2 before changing back to another test value, or constraints are not satisfied for some reason.

We'll let you know as soon as we get a chance to improve this.

David

[rds3000]

One last note on this issue:

The Insight Energy Analysis model does properly recognize the curtain wall mullions as shading elements, so the shading effect will be seen in Insight Optimize results.  Remember that any results in the 'Shades' widget will be for shades in addition to the modeled shades, so use the '0' overhang depth in Insight to isolate the effect of your mullion spacing experiments.

David

[Anonymous]

Hi guys ! 

I am having a bit of a problem that I dont really understand. The sun study works just fine in 3d but when I create 3d plan view it does not affect curtain wall. Any ideas ? 

Thanx ! 

[Anonymous]

Alright this morning with a fresh mind I have figure out why it wasnt showing. Level of detail has to be set to FINE and then all works fine !