Re: window glass treatments

From: Mark (dad4lou_at_yahoo.com)
Date: 10/26/04 

Date: 25 Oct 2004 21:27:32 -0700

jbuch <jbuch@CUTHERErevealed.net> wrote in message news:<clhrsn0mho@enews4.newsguy.com>...
> Mark wrote:
>
> > Hi all,
> >
> > I figured this august group of knowledgable people could solve a
> > mystery for me.
> >
> > As I was listening to yet another window salesman's pitch, he
> > mentioned that the coating on the glass would let light pass, but
> > would minimize heating in the summer. Now that made sense to me, but
> > then he followed up by saying that in the winter, it would let the sun
> > help heat the room.
> > I'm familiar with bandpass optical coatings that will reflect IR and
> > pass visible (and if they're good, also block the UV), but not with
> > any that change based on temperature. To work as advertised, I would
> > guess that the lower cutoff would have to be temperature dependant and
> > rise in frequency with temperature.
> >
> > Having never created one like this myself, I was wondering - is it
> > possible? and if so, what technique creates variable coatings? Sadly,
> > all of mine are stable over a wide range of temperatures. Has my
> > little grey cells become even more disfunctional with age than my wife
> > suspects?
> >
> > Mark
>
>
> Listening to salesmen talk about technical stuff can wear your mind down.
>
> Did he say "LOw Emissivity Windows" or "Low -e glass"? Or did he say
> anything at all that you can remember that relate to the name of the
> technology involved?
>
> You could provide whatever you otherwise remember of the discussion.
>
> In case he mentioned low emissivity windows, which have been around for
> over 20 years in various forms, go to :
> http://www.aip.org/pt/vol-53/iss-11/captions/p29box1.html
>
> or do your own google search for "low emissivity windows theory" or some
> similar terms, if you want to knoow the theory of UmpidySquat Windows,
> try "UmptidySquat Window theory" as search terms.
>
> Jim
>
>

Did I forget to mention that it was low e (guess I thought it was
understood).
The part that unusual was the change in cut-off frequency from near IR
to thermal IR in the winter. Had to do with outside pane coating
since it was the one that saw the temperature extremes. I thought
about maybe they used a multi-layer coating with a layer of high
expansion material that would shift thickness (as measured in
wavelengths) appreciable over only few degrees to
reflectance/emissivity.

Mark

Relevant Pages

  • Re: window glass treatments
    ... Mark wrote: ... > any that change based on temperature. ... Listening to salesmen talk about technical stuff can wear your mind down. ... or do your own google search for "low emissivity windows theory" or some ...
    (sci.materials)
  • Re: ALLOWING LIGHT TO PASS BUT NOT HEAT
    ... Allowing light to pass but not heat ... cutting off temperature rise and sweating. ... the coating developed by UCL researchers is made ... where the arrangement of electrons changes. ...
    (sci.chem)
  • Re: ALLOWING LIGHT TO PASS BUT NOT HEAT
    ... Allowing light to pass but not heat ... cutting off temperature rise and sweating. ... the coating developed by UCL researchers is made ... where the arrangement of electrons changes. ...
    (sci.physics)
  • Re: ALLOWING LIGHT TO PASS BUT NOT HEAT
    ... Allowing light to pass but not heat ... cutting off temperature rise and sweating. ... the coating developed by UCL researchers is made ... where the arrangement of electrons changes. ...
    (sci.energy)
  • Re: window glass treatments
    ... > any that change based on temperature. ... You're right about dichroic,, coating. ... The glass reflects most of the I.R. keeping summer heat out. ... not solar gain. ...
    (sci.materials)