[Stoves] radient heat capture

[Richard Stanley]

Andrew, 

Your recent statement;
> "It all sounds logical to turn a low emissivity flame to radiant heat
> like this and heat transfer seems the next area for big improvements"
> with a clean burning stove.", 
is the understatement of the year.

How does one measure radient heat versus convective heat ? seems a bit of both emmanate from any fire but other than feel for heat "below the fire" how do you determine the ratio and what are the guidlines for enhancing the latter, and,  do you always want it ? 
You start with wood mostly all convective it seems; the fire progresses to coals heat radiates in al directions (Am guessing that this is the radient heat end of the "energy continuum". heat ing distance drops off markedly but it emmanates in all directions. Big stove design problem. Shitft the fule load up lower the pot…been a hot topic for years now…
Until now on one has come up with a good ( meaning, beyond technical,  applicable/ reliable. easily replicable/ solution for application-in-the-developing nations) solution.
I recall a short mention of radient heat effects and having it dismissed as insignificant  a pre Ethos meeting several years back. Many as well dismiss the value ofthe hollow core int eh briquette other than for more rapid drying, but there it is again... 

You have a mass of a certain material We have the data for insitu energy value. we have been consistently getting far beyond what that energy value states with the apparent internal reflectance off the internal core in the briquette but that energy, if radient, is not necessarily being directed upward.  Paul, you mention that you are redirecting that radient heat upward with use of your stainless steel ring. Is the ring directing "hot gasses" as so many have been proporting on this list, sure thats the opbious part but what else is happening here: Is it alos re radiating infra red heat back onto the pot --and if so what are the mechanics of the configuration for enhancing the latter? Its got to be morte than jsut clearance between pot and ring that we are talking about folks..what about shape beyond cylindrical. is it nore effective if made conical, domed, or  dished ?

 There has been a great deal of attention given to  gassification but what about Pauls discovery and the residing use of screens in baseboard heaters and lamps etc.  as you and others mentioned.
Seems many of us need to go back to the drawing board, on this one !

Thanks again Paul, and Ron for highlighting it.

Richard Stanley
www.legacyfound.org

 
On Mar 4, 2012, at 1:29 AM, ajheggie at gmail.com wrote:

On Sun, 4 Mar 2012 05:44:19 +0700, Paul Olivier wrote:

> Someone had left a wire strainer on the floor of the university building
> where I was working.
> By chance the wire stainer had the same diameter as my burner housing.
> When I put it over the burner and burner housing, it fit perfectly and
> turned red hot.
> I had never felt such heat before.
> 
> So I went to the local market and found wire strainers of finer apertures.
> These worked much better than what I first tried.

It all sounds logical to turn a low emissivity flame to radiant heat
like this and heat transfer seems the next area for big improvements
with a clean burning stove.

I imagine as long as the wires are kept above the autoignition point
of the gases in the flame or the flame has completely burned out
before touching the strainer there won't be much effect. I wonder how
this sits compared with the wire gauze in a Davey Safety lamp, which
is there specifically to remove the source of ignition from the gases
outside?

Have you managed to analyse the offgas before it is burnt to see if
the blue flame is down to CO or just good premixing?

AJH


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