[Stoves] Fire Stump / stump-incuts

[Tom Miles]

Roger,

 

You will find staged combustion and staged gasification employed in many
designs. Providing ideal geometry and air control for good combustion is
fundamental to the rocket design which is the basis of the designs at Burn
Design Lab, Aprovecho and elsewhere. You will find the TLUD (Top Lit
UpDraft) stove designs are a gasifier with secondary gas combustion. The
designs gets complicated when you add the needs for efficient heat transfer.
So you may have devices with high combustion efficiency (fuel savings) but
poor to mediocre heat transfer. 

 

If you have mixed both aspects in your design then you should be able to
test it using the range of cooking tests (Water Boiling Test, Kitchen
Performance Test) and emissions tests that are listed on the PCIA, Stoves
and other websites. 

 

The final criteria for developing countries is cost. You can see the cost
and other targets on the Global Alliance for Clean Cookstoves site.
http://cleancookstoves.org/ 

 

Tom    

 

From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Fireside
Hearth
Sent: Thursday, July 28, 2011 12:49 PM
To: stoves at lists.bioenergylists.org
Subject: Re: [Stoves] Fire Stump / stump-incuts

 

Hi Tom.....and thanks. 
    My wife and I are asking the following question. Why isn't the secondary
combustion process be applied in cooking? or another angle why could these
appliances do both jobs?
Are we needing to assume that costs of making such a unit are too high? If
so what could be done to bring this characteristic into the realm of
affordable? I realize that we both have different angles on this issue. Mine
obviously is centered on reduction of consumption, yours would seem to be
centered on higher burn temps to combat pollution. Is a "hybrid" design
something to look at? has it already been dismissed? I feel strongly that we
have mixed both aspects in order to achieve the performance we have gotten. 
Roger and Bridget

  _____  

From: tmiles at trmiles.com
To: stoves at lists.bioenergylists.org
Date: Thu, 28 Jul 2011 11:36:30 -0700
Subject: Re: [Stoves] Fire Stump / stump-incuts

Roger,

 

We developed the efficiency and emissions protocols for heating appliances
that you refer to in Oregon in the late 70s and adopted them in the early
1980s. They were later adopted by the EPA. We did the initial work in
collaboration with other countries which adopted similar protocols. The
$20,000 fees charged by OMNI and other labs are what we live with. Most
stove companies use consultants or their own equipment to get preliminary
numbers. The equipment used for improved cooking stoves (like the PEMS -
Portable Emissions Monitoring System - available from Aprovecho Labs) are
not a substitute for the EPA tests. 

 

Our focus here is for cooking stoves for developing countries not domestic
heating appliances. Domestic heating appliances get the higher efficiency at
substantial costs, either for fuel preparation (pellets) or for controlling
combustion and heat transfer. Here we try to achieve higher efficiency and
lower emissions at very low costs but the appliances are for cooking, not
heating, and the metrics are different. 

 

Jim Jetter of EPA just presented a webinar testing done for cooking stoves,
not domestic (US) appliances.   See www.pciaonline.org

 

Tom   


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