Hi folks,

I'm currently involved with a prospective project to retrofit an existing urban office building in a robust four-season climate. The building is roughly 60 floors, circa early 1960's, with an original single pane, non-thermally-broken aluminum curtain wall, and anodized aluminum spandrel panels. We don't have exact glazing specs yet, but COG is likely in the range of: SHGC=0.43, Tvis=0.53, Uval=1.00

Here's the question: If you wanted to retrofit the facade to improve overall building energy / occupant comfort (heating, cooling, solar control, daylighting, MRT adjacent to glazing, etc.),?but were required to retain the original glazing (for architectural considerations, or due to impracticality of complete facade removal with existing tenants), what options might you pursue? Additional potential constraints of note (still to be determined) may include: mullion depth limitations, structural facade load limits. Also worth noting that the building's rectangular plan features a SW-facing long-axis orientation, so spring-through-fall cooling loads are likely to be enormous. Finally, if a second skin solution is to be pursued, we're also keen to keep an eye on condensation issues.

What's the latest, greatest thinking in this arena??Suggestions / comments much appreciated....

cheers,

Adam