Vertical illuminance at eye level

Grasshopper
1

Hello,

I am trying to calculate DGPs for a whole year in hourly values in DIVA for Grasshopper. To calculate vertical illuminate on the eye level (Ev), I considered a small grid in eye level facing to the window and extracted the hourly values of vertical illuminance.

However, when I manually calculate DGPs based on the following equation, I observed DGPs exceeding one.

DGPs = 6.22 × 10−5 * Ev+ 0.184

I have two question:

First, if my assumption of considering a vertical grid is correct?

Second, do I need to define a threshold for high values of illuminance when calculating DGPs based on this formula?

I would be thankful if anyone can guide me in this matter.

Maryam

2

Did you find any answer regarding the grid? In order to have vertical illuminance at eye level for many positions, do i have to create many small vertical grids for each position around the space?