[Greenbuilding] Solar Gain from South facing windows

[Ted Inoue]

I was unclear. What I'm saying is that ALL dielectric filters are angle
dependent, so there WILL be a spectral shift in all low-e windows as the sun
angle changes. What I'm guessing is that while this is the case, the shift
in the IR wavelengths being reflected turns out to be insignificant in
reality because it's a broad band of wavelengths that are allowed to pass.

sorry to confuse issues.


On 6/14/07, Keith Winston <keith at earthsunenergy.com> wrote:
>
> Yes, I used "tune the window" as shorthand. It is in fact what you care
> about. You don't, after all, tune a car, you tune the engine. No, not
> the engine, the carburator. No, not the carbuerator, the jets. Oh, to
> (*&%  with it, just tune the %&#%$ car, will you? ;-)
>
> While the link Ted offered mentioned dielectric coatings, it didn't say
> anything about insolation angular specificity. It only mentions them in
> conjunction with noble metals for the purpose of improved low-e
> coatings. Nothing about angle of incidence of insolation. And again,
> think about it: the sun is going to hit the glass from a variety of
> angles throughout the day, and throughout the year. Then add in the fact
> that the glass might be mounted due South, due West, etc. I'm not sure
> that an angularly-tuned window (coating) would offer much, though in
> high lattitudes it might. I haven't seen any info about anyone working
> on them. Certainly they aren't available (famous last words).
>
> Keith
>
>