Hi There - really loving using PreDesign as a way to kick off a project armed with a base of solid info. I’ve been combining it with our sustainability strategy analysis to put together a project “toolkit” of viable strategies for eco/green/sustainable buildings.
I have one question/ possible red flag, though: the glazing ratio analysis doesn’t seem to be responding to different building orientations. Or rather, the “Optimal strategy” doesn’t. For example, the latest project, on State Street in Belvidere, Illinois, shows exactly the same glazing ratio recommendation for all four facades. (73%). Surely that cannot be correct!?
The “Typical strategy” seems to (maybe?) respond to the different orientations as you “might”? expect (even then, I question 60% north facade versus 36% south facade - this is probably not typical for that area):
N: 60%
E: 36%
S: 36%
W: 36%
Can anyone explain this? Is this a bug? The results are different across multiple projects, but they’re all the same in that they defy intuitive logic.
The glazing ratio analysis is not suggesting a glazing ratio recommendation, it is recommending a glazing strategy that will give you the highest glazing ratio.
What changes between the facades is the recommended strategy rather than the max ratio achievable.
For example in Belvedere IL, the optimal strategy to achieve max glazing ratio on South facade is:
Triple glazed low-E, non-metal, no shading, great glazing
but on North facade it is:
Triple glazed low-E, non-metal, no shading, basic glazing
The only difference is the glazing type, because on the North facade, overheating has negligible impact so the glazing doesn’t have to be as good.
The typical strategy is defined by the building type and climate zone. So in this location we have Double glazed low-E, non-metal, no shading, basic glazing. In this case the strategy does not change by facade, so instead what changes is the max glazing ratio, and South/West have pretty low values due to the high impact of overheating sun, which this strategy only does a moderate job of controlling. For the North facade, the insulating ability of this strategy is the limiting factor, and this cannot insulate as well as the triple glazing so it gets capped at 60%.
Do you disagree with this as a typical strategy for the area? Or do you think the glazing ratios suggested for this strategy are incorrect?