Best direction for a flat roof and minimal slope

[MrTWales]

I wonder if any of you guys can point me in the right direction here. I want to install on a flat roof: the area is 6.3m x 5m (ignoring the edge bit, ie this is the roof edges that are over the walls so weight could be placed right at the edge). The roof is facing pretty much flat South West along the short edge, and the roof is sloped about 2 degrees towards South West for drainage. There is pretty much no shade until about 9:30pm. 

 

I want as flat as possible and I have been thinking that the best direction is S/W, so 10 degrees + 2 dgrees of angle. The downside is that more ballast is needed than for an EW orientation and you need more gaps along one edge for shading. 

 

I'm just wondering how much worse an E/W set up would be as it would actually be NW/SE. It is possible that this direction may mean that I could fit more panels on, depending on the size. 4 x 3 400w panels is definitely OK but an NW/SE set up may mean other options potentially. It looks better too.

 

Is there a website where I can get some idea of how well (or badly) this would work?

[Dillsue]

On 27/06/2022 at 09:45, MrTWales said:

Is there a website where I can get some idea of how well (or badly) this would work?

PVGIS

[bontwoody]

I found this very good https://re.jrc.ec.europa.eu/pvg_tools/en/ you could calculate each direction indivdually