IES-VE User Forum

Hi,

I have several glazing panels some that open and others that are fixed of various sizes and so have modelled these as seperate windows, immediately next to each other, creating one large window. I have applied the same construction to all of the glazing however since they are all in a single recess in the external wall I am not sure using local shading 'recess' in glazing construction how to deal with the 'window size'.
How is window size linked to the shading? I have only one recess of 200mm deep to apply to the entire glazed area of 5m x 1m high. Do I have to create a seperate glazing construction for each size of small window? (But if I do this would create side shading for each small window and give more shading than is actually present?)

Hope you can help

I think you are right with the potential for over shading.
I'm not sure how much difference it'll actually make but it will have an effect.
Have you done a feasibility study as to how much effect it will have?
If you do then place your findings on here and help out others that are thinking the same.

One option open to you and certainly one I have used in the past is to model a "fake" facade.
Here's an idea of what I'm talking about:


If you decide to go down this route then draw the facade in blocks then merge together.

I actually prefer this method most of the time because it works for visualisations as well. Something you may or may not know is that the daylighting tools (Flux and Radiance) don't know anything about the apache constructions - you need to set the shading coefficient (or transmittance) of the glass in them again. Same goes for shading devices attached to the constructions. I would love IES to get their act together and connect the dots but I've been waiting years so just work around it.

Thanks for the reply.
The 'fake' facade would be ok visually but would impact on the thermal characteristics of the facade and hence alter the room gains that I am trying to determine.
Useful info on daylighting calcs - thanks (will be useful later) but not concerned with that for this model exercise.

My original question for IES still stands though - If you want to model a 'multi window' glazed area do you need to change the 'recessed' information in the construction details for each part of the window (and input each window size' into the construction details) or can you do this globally some how for the entire window? Or perhaps the only way to model the recess for a multi window glazed area is to model the local shading as 4no shades ie on on each leading edge of the overall opening?

would be interested to see the magnitude of this thermal impact but all the best with your quest.

I'm faced with exactly the same problem as the OP.

How to model a a single recess across a panel of windows of different sizes.

Any answers?

Hi,

As alluded to in the earlier conversation on here, if you want to model these via Constructions Database shading interface then yes you will need to create separate constructions for the different windows.

Additional ideas

- bypass the shading devices interface and make adjustments to your glazing properties to build in the effects you think the recess will have. Again might require different constructions for different dimension windows
- model some local shades around the windows and use SunCast to calculate the small shading impact they have.

Might be worth your time to do some test cases and judge the impact it is having on the room loads, Zap suggested it may be that the thermal/energy calc effect isn't significant and it can save you some time. For daylighting calculations you ave different options by modifying surface properties for the windows or in Radiance running with the inner volume switched on which again saves any extra modelling.

Phil