that sounds great, I have roughly worked out how to pull the information from the model but im already hitting a problem
W = glazing - see problem below
A = thought of using a formula for either ceiling area and room area, or room area *2 then for the walls using the perimeter from room area * storey height
R = constant for most cases
T = constant for most cases
u = constant for most cases
M = constant
note about constants, they can just be changed on the fly, or within a parameter for the window family.
Glazing!
It seems that Revit is taking the area for glass/glazing from all sides, so it is well over.This is the equation
DF = MWuT/A(1 – R2)
Where:
W = total glazed area of windows or roof lights
A = total area of all the room surfaces (ceiling, floor, walls and windows)
R = area-weighted average reflectance of the room surfaces
M = a correction factor for dirt
T = glass transmission factor
u = angle of visible sky
Guide values for a typical dwelling with light-coloured walls are as follows (for more accurate values, refer to CIBSE Lighting Guide 10):
R = 0.5
M = 1.0 (vertical glazing that can be cleaned easily)
0.8 (sloping glazing)
0.7 (horizontal glazing)
T = 0.7 (double glazing)
0.6 (double glazing with low emissivity coating)
0.6 (triple glazing)
u = 65˚ (vertical glazing)
Posted: Wed Jul 06, 2011 8:00 am
