Duncan, Fifty years ago when I was doing A level physics, absorption and
radiation coefficients of a coloured surface were directly related. Good
absorbers were good radiators, etc Regards, David
----- Original Message -----
From: "Duncan McFadyean" <ami@mcfadyean.freeserve.co.uk>
Subject: Re: Europa-List: black body radioation
<ami@mcfadyean.freeserve.co.uk>
>
> I beg to differ.
> Black is far more absorptive than white. But the emissivity is little
> different between the two colours; in other words, if heat is being LOST
by
> radiation, then black is only marginally more efficient than white. Of
> course "radiators" transfer heat mostly by conduction, which is not
affected
> by colour.
>
> Duncan McF.
> ----- Original Message -----
> From: "Fred Fillinger" <n3eu@comcast.net>
> To: <europa-list@matronics.com>
> Subject: Re: Europa-List: black body radioation
>
>
> >
> >> I was wondering whether white paint would massively affect
> > the ability of
> >> the radiators to dissipate heat. My gut feeling tells me
> > that the bypassing
> >> air molecule does not mind the color of the hot metal bit
> > it gets heated up
> >> by. But then again ... there was something in science
> > class many years ago
> >> about dark body radiation.
> >> ....
> >> Please advise.
> >>
> >> <Thomas, N81EU>
> >>
> >
> > You want black, not white. Quantum theory, Kichoff's laws,
> > good absorbers (black) are good radiators (shedding heat of
> > the hot fluid). But with tradeoff as your radiators will be
> > absorbs the sun's heat in a given flight condition.
> >
> > But as a practical matter, you'd have to dip them in paint,
> > I don't think we want to do that. So anything shot on just
> > the front shouldn't matter. Black will disguise the fact of
> > radiators there viewed from a distance. White would look
> > odd to me on such a device. Gold might look like it was
> > anodized the way a popular aircraft part comes. Silver
> > metallic phony; we homebuilders use too much of that.
> > Office beige? Whorehouse lavender? :-)
> >
> > Reg,
> > Fred F.
> >
> >
> >
>
>
> ________________________________________________________________________
> "Fantastic service... saves a lot of time for me... I only have to go to
one page."
> http://www.doctors.net.uk/login/?shorturlid=2854
> _______________________________________________________________________
>
>
---
|