We are trying to calculate the % of the surface exposed of a certain window (located on a specific zone within a bigger building), facing NW, during summer days, at a 40º latitude location, for different kinds of shading elements. We are experiencing several problems, namely:

1 – the calculation algorithm doesn’t seem to be working, since when we uncheck the “Fast Calculation” option the program only returns null results;

2 – The “Fast Calculation” algorithm doesn’t return uniform values. We believe that for uniform geometry and planar surfaces, we should get uniform results, so we don’t understand this;

3 – The Analysis Grid distance to the window seems to have an exaggerated importance, since we tried with a 10cm distance (to the inside) and obtained 4 times less % exposed then when locating the Analysis Grid coincident with the glass (near 0cm distance);

4 – We tried a shading solution with 20cm projection elements separated by 30cm and when applying (in the very same position) shading elements with 10cm projection separated by 30cm, we obtained less % of area exposed, which cannot be possible. However, these two analysis were run with different sized grids (the smaller one was intended to speed up the calculation, but all other aspects remained the same);

5 – We get different results with different sized grids, even when the number of cells are adapted in order to maintain approximately the same cell side size;

6 – We also get some minor differences for exactly the same runs in different computers.

We are a bit upset with these problems, since we have a deadline to deliver this project in 15 days, so we have great urgency in solving them.

Thank you.

Best regards,

André Coelho & Gonçalo Machado,
Ecoperfil
Portugal