Rooflights specification

PaulCarey · Posts: 14 Location: Stalybridge, Nr Manchester

Ok so can someone refresh me if I can model a percentage area of rooflights on a roof?

According to the glazing tab I can apparently set it up, but then I can't seem to apply it and when i do I either get 100% or specified height and width.

I want to do that because the model we have is an enormous warehouse and we end up with over a 1000 windows otherwise which is impossibly slow to run.

Cheers
Paul

Laurent_Support · Posts: 292 Location: Vincennes

Hello Paul,

There is a solution.
Go down on your roof block, open the Model Options and set the roof-wall transition angle so that pitched roof becomes (temporarily) a wall. Then select each surface, choose the % you need to generate the appropriate window area. Once down click on a drawing tool (window, door, whatever) just to change your surface to Custom surface.
Now your window won't be regenerate and you can go back to the model options to set back the transition angle you initially have.

Bu the way if you have many windows you can Merge them in Model Options provided you don't need some specific illuminance calculation.

Best regards,

Andy Tindale · Posts: 1148 Location: Stroud

Just to add to Laurents' points, the DesignBuilder lumping procedure should not be affected by how the windows are defined or whether they are placed on a roof or a wall - it should be down to similarity of the windows and the merge settings on the Advanced tab of the model options. There will be no lumping of windows in a zone if daylighting control is requested in that zone.

Andy

PaulCarey · Posts: 14 Location: Stalybridge, Nr Manchester

Chaps,

Thanks. Seems a bit of a long winded work around, but I'll give it a try.

Maybe taking the percentage area toolbar out of the rooflights tab might be useful then seeing that it doesn't really do it.

Other than that or getting it to work properly. A little frustrating when trying to do quick EPC's on huge and mean really huge warehouses.

Paul

Andy Tindale · Posts: 1148 Location: Stroud

Paul,

You can't currently set a % glazing area for the roof (unless as Laurent says you temporarily set it as a wall by tweaking the transition angle) but you can set up repeating windows of fixed length and width. This is entered under Roof Windows / Skylights on the Openings tab.

I'll look into why the % glazing option isn't available for roofs.

Andy

PaulCarey · Posts: 14 Location: Stalybridge, Nr Manchester

Thanks Andy,

We did it the way Laurent suggested and it was alright for all but one of the roof pitches which stuck about 150 windows or more into one wall.

Set it back okay. In the end on that wall/roof we just copied at top model (building) level across and seems okay. The only reason we are asking for this is to assess the impact of the % rooflights on this, which is apparently quite large and takes the building from a B to a C on the EPC. Think it's to do with the lack of solar gain at a guess can't be daylighting as it's not switched on.

Anyway, thanks for the advice much appreciated as ever.

Cheers
Paul

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