[Stoves] Secondary combustion.

Tue Aug 2 11:00:34 CDT 2011

Hello.....

       This tid bit may or may not help, but from field work here on Vashon I found that the EPA certified stoves which we installed had their greatest success at curbing both smoke and consumption were the ones owned by people who took the time to really understand the product and it's need for properly cured fuel. It was very clear that the stoves had much better secondary burn and used less fuel when proper curing was done. I believe that reducing consumption also made it easier for the average homeowner to have the time and energy to actually cure their wood......I think this is one big reason I am in favor of any device which reduces consumption as it gave my clients more time having to do less in the process of ensuring dry fuel was available.
      I also used to run around with a moisture meter in hand as once in a while a client would pop off with a complaint about a stove we installed. We would show them the content of their wood, then burn a densified log in their stove and often shock the heck out of them. This only goes to show the importance of both great product and great education and the hand in hand correlation. No matter how great your product is, if the end used does not fully understand it's needs there will be no benefit to them or the environment.
Good day to you all....Roger.

> From: crispinpigott at gmail.com
> To: stoves at lists.bioenergylists.org
> Date: Tue, 2 Aug 2011 09:51:05 -0400
> Subject: Re: [Stoves] Secondary combustion.
> 
> Dear Dr Tom and All
> 
> I have been looking at the speed at which the incoming secondary air
> increases in temperature and happily found this
> http://www.people.fas.harvard.edu/~yhuang/research/thesis.pdf which says
> (page 46/155) that the collection of heat by air from a radiative source is
> highly dependent on the moisture content and in fact the temperature of that
> moisture (Planck effect) with a substantial portion of broadening of
> spectral lines of absorption being caused by Lorentz and Doppler broadening,
> both strongly affected by temperature.
> 
> Let's suppose cold air through a small jet heats very rapidly from the
> moment it emerges from the hole. It will expand rapidly with all sorts of
> perturbations commencing and lots of chaotic mixing. Good news. It is taking
> heat out of the fire, one way or another. Will this grossly affect the fire?
> I guess that also depends on the moisture content, but if we say that the
> ultimate temperature is 1500 K then then total energy in the secondary air,
> preheated or not, is a pretty small portion of the total.
> 
> If that small portion could produce a significant difference in CO
> combustion, then it would matter.
> 
> Regards
> Crispin still thinking about it
> 
> Dear Tom and all.
> 
> I work with industrial  gas furnaces,
> 
> Some use a mixture of gasses with H2, CO, CO2, CH4 with traces of C2's to
> C4'4's. -  with a HV as low as 16 MJ/m3.  Others burn Natural gas with a HV
> of 40 MJ/m3.  Some have preheated air and some do not.
> 
> All run with a minimum of excess air, with about 1.5 to 2% O2 in the flue
> gas and very low CO.
> 
> The common factor in all these flames is the 3 T's .  Turbulence,
> temperature and time.  All having turbulent mixing,  A well insulated
> combustion chamber, and a large area for the flame to burn to completion.
> 
> This is the scenario that we need to try and emulate as far as possible in
> the secondary flame of our stoves. How close we can get to this is the big
> question.
> 
> Regards,
> John Davies
> 
> -----Original Message-----
> 
> From: stoves-bounces at lists.bioenergylists.org
> [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Thomas Reed
> Sent: 31 July 2011 01:38 PM
> To: stoves at lists.bioenergylists.org; Paul Anderson; Hugh McLaughlin
> Cc: stoves at lists.bioenergylists.org
> Subject: Re: [Stoves] Stoves Digest, Vol 11, Issue 38
> 
> Crispin and All
> 
> Let's explore the plus and minus of preheating secondary air.  
> 
> 
> 
> 
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