[Stoves] radiant heat capture, total heat measurement

Frank Shields frank at compostlab.com
Wed Mar 7 15:30:23 CST 2012


Stovers,

Quick question - does radiant heat require the subject be 'n sight' of the
object being heated?

Thanks

Frank




-----Original Message-----
From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Richard
Stanley
Sent: Wednesday, March 07, 2012 12:27 PM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] radient heat capture, total heat measurement

Andrew,
 Its the old quandry of  Brownian movement then, eh ? 

Still that "sense we an animals all have of "heat' and "warmth " 
remains well beyond degrees of temperature oer se. 
Something missing between science and perception that unless clarified and
quantified would seem to leaves stove performance assessment abit untidy.

Richard Stanley
www.legacyfound.org
=======

On Mar 7, 2012, at 11:44 AM, ajheggie at gmail.com wrote:

On Tue, 6 Mar 2012 07:47:03 -0800, Richard Stanley wrote:

> If radient energy is the mother and conductive convective "heats" are
added expressions of it,  then why does one rely only upon measurement of
thermal heat only in these more tangible but not necessarily more
influential bands of the spectrum,  as the standard  measure of cooking
efficiency ?

I suppose it's to do with what means we have of producing the power to do
the cooking, fire is the easiest way of liberating the energy and
transferring it to the cooking pot. Plants have concentrated sunlight into
wood.

Light can plainly be used for heating, didn't one of the ancient greeks
write of the concentrated beams reflected from polished bronze shield
setting fire to ships rigging?

> Micro waves in themselves are not "hot" but they do a wonderful job of
heating by disturbing molecules, just as the visible band of radiation we
call heat, does. 

Presumably there was no evolutionary advantage in having an organ that can
sense infra red in the same way eyes interpret light but many animals do
have increased sense of warmth, snakes can hunt by it.

Microwaves for cooking have only become commonplace in the last 60 years
but the principle is the same as other means of heating, they selectively
excite water molecules. The microwave radiation is tuned to deliver in
frequencies which water molecules will accept in discrete amounts, otherwise
they would just pass straight through.

> My naked supposition is therefore, that beyond a normal thermometer or one
measuring just IR, one needs a more comprehensive "molecule disturbing"
> measurment device

A thermometer is something that reacts to change in temperature, it doesn't
measure the activity of molecules but rather compares the effect the
molecules have on a substance.

I don't think it is possible to directly measure the state of a molecule
without changing it.

AJH

_______________________________________________
Stoves mailing list

to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org

to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org

for more Biomass Cooking Stoves,  News and Information see our web site:
http://www.bioenergylists.org/



_______________________________________________
Stoves mailing list

to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org

to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org

for more Biomass Cooking Stoves,  News and Information see our web site:
http://www.bioenergylists.org/






More information about the Stoves mailing list