[Stoves] Hi TLUDers -- and EPA testing questions

rongretlarson at comcast.net rongretlarson at comcast.net
Sun Oct 23 20:22:23 PDT 2011

Dean with stove ccs. Thanks - only a few slight questions (maybe for others) - but a few inserted further comments below. 

----- Original Message -----
From: "Dean Still" <deankstill at gmail.com> 
To: rongretlarson at comcast.net 
Cc: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>, "Paul S. Anderson" <psanders at ilstu.edu> 
Sent: Sunday, October 23, 2011 6:54:43 PM 
Subject: Re: [Stoves] Hi TLUDers -- and EPA testing questions 

Hi Ron, 

1.) For the EPA we tried to burn all the fuel about 2/3 as wood and 1/3 as charcoal to get the best fuel economy. 
[RWL: Most char-making estimates are that (if char had been retained), the char weight would have been about 1/5 to 1/3 (average of 1/4??) of the initial weight - leaving (maybe) 1/2 of the initial carbon in the biomass. But because pyrolysis removes most of the hydrogen, more than half of the initial energy content has appeared as gases/liquids when pyrolysis stops and gasification begins. Just saying that the 2/3 and 1/3 values could be right on, but the analysis is pretty complicated. ] 

2.) As far as I can tell, no primary air can make it up through the pellets until 2/3 fuel is gone and the bottom air gets up through the remaining charcoal. 
[RWL: It sounds like there was no "door" placed over the usual Stove-Tec opening, so perhaps other owners of Stove-Tecs can also test this in some way. It sounds like it would have been difficult to capture much char - but you were seeing several nice advantages from top lighting. For those not having experience with TLUDs, Dean's reference to "no primary air can make it up", means that the oxygen is "entirely" used to produce carbon monoxide. I am presuming that for Dean's specific geometry, there is some side air entry when the pyrolysis front has moved down by 2/3 (but I may not yet have the geometry right).] 

3.) I don't remember exactly. We used a StoveTec Rocket and added something like a 9" chimney. We probably used around 1000 grams of fuel to begin. 
[RWL: I think it is great that you tried this approach and had good results. I hope others will try something similar. The emissions results indicate this is a promising approach. 

4.) No. 
[RWL: Anyone know the PCIA rules on using convective shields? Shouldn't their use be strongly encouraged? It sounds like you have given your own test results and they may not have been the same as in the PCIA/EPA report?] 

Thanks for all above and next 2 answers. ] 

5.) No field tests yet. 
6.) TLUD cost could be the same as a Rocket. 

I hope that some place in the world will be positioned to make 100% renewable pellets, get carbon credits, and use super clean TLUDs. We'll see. Natural draft is obviously easier than having to use an electric fan. I think that it's possible that some government or large business will follow the BP model. I think that the job of the stove movement is to be ready with the engineering design principles for TLUDs, fan stoves, super clean Rockets when a capable entity is ready to move forward. 

[RWL: There is a lot happening out there now with TLUDs (and Nat Mulcahy's very different TLOD) - with both ND and fans. Also a lot of business models - including quite a few where the char is saved for (a little because of) carbon negativity and (more now for) soil augmentation reasons. Your tests showing such good emissions and efficiency results should help make these sort of rocket stove improvements happen faster. Thanks again for doing the testing and for many good answers above. 
Sorry - two more questions - the charcoal-consuming jikos looked pretty bad in the PCIA report. Can you (or anyone) report on any emission differences in your case during the early and late parts of your (or EPA) runs? Can I assume that the efficiency numbers for the jikos took no notice of the energy losses in making the charcoal? 

Ron ] 

All Best, 


On Sun, Oct 23, 2011 at 2:59 PM, < rongretlarson at comcast.net > wrote: 

Dean - with few ccs. 

Thanks for the added information. Just a few more questions: 

1. Have you ever tried to maximize char production - and what amount did you then obtain, if tried? 

2. What was the mechanism for controlling primary air, if any - and did that help with the test? 

3. For the reported PCIA numbers, what were the key dimensions (diameters, heights, fuel amount, etc). 

4. Were you using a convective shield? 

5. If tested in the field, any response yet by users? 

6. Should manufacturing cost and lifetime be similar to your rocket? 

Thanks in advance. 


From: "Dean Still" < deankstill at gmail.com > 
To: rongretlarson at comcast.net 
Cc: "Discussion of biomass cooking stoves" < stoves at lists.bioenergylists.org >, "Paul S. Anderson" < psanders at ilstu.edu > 
Sent: Sunday, October 23, 2011 3:16:18 PM 

Subject: Re: [Stoves] Hi TLUDers -- and EPA testing questions 

Hi Ron, 

Paul, Christa, Paal, Art and others taught at several TLUD oriented Stove Camps how to make TLUDs. All we did was to change different amounts of air, mixing, heat transfer strategies to the prototype design under the emissions hood. The emission hood lets us tune a stove the way cars are tuned. 

The TLUD we sent to Jim has a lot of fast air and mixing at the top of the fuel bed. We have the fuel sitting on a screen letting in as much bottom air as possible so the charcoal catches on fire and helps to cook the food or simmer the water. The stove burns up all the fuel. We pay a lot of attention to making the heat transfer to the pot as good as possible. 

I think it's really neat that a stove can either make bio-char or not by controlling the bottom air so consumers can pick what they want the stove to do. 

Great to hear from you. 


On Sun, Oct 23, 2011 at 1:03 PM, < rongretlarson at comcast.net > wrote: 


Dean (cc list and Paul) 

Thanks for the PCIA link - which I found most interesting. 

I do not know anything about the Stove-Tec TLUD - which came across as being very successful. 

Can you either describe some details of your design - or send us to an existing web description? What might you have done differently than other TLUDS? 

Is there a reason that data for it were not in all the PCIA report graphs? 


From: "Dean Still" < deankstill at gmail.com > 
To: "Paul S. Anderson" < psanders at ilstu.edu > 
Cc: "Discussion of biomass cooking stoves" < stoves at lists.bioenergylists.org > 
Sent: Saturday, October 22, 2011 6:28:32 PM 
Subject: Re: [Stoves] Hi TLUDers -- and EPA testing questions 


Hi Paul, 

Here's what PCIA published on the first round of testing. I see that a lot of your questions are answered there. 

My idea was that if TLUDers find it useful they can for free use our emission equipment. 

All Best, 


On Sat, Oct 22, 2011 at 5:00 PM, Paul S. Anderson < psanders at ilstu.edu > wrote: 

Dear Dean and all, 

I know of at least 5 TLUDs, each from a separate PCIA Partner, that have been proposed for testing by Jim Jetter for this third round. 

The Aprovecho offer of a free tune up under the emissions hood is nice. Is that offer matched by Zamorano in Honduras or CREEC in Uganda or any other place with PEMS equipment? 

Question: Does a person need to go to Oregon, or could the stove be sent with instructions? Cottage Grove is only convenient and inexpensive for those who live within a hundred miles!! 

And does Aprovecho have the SAME fuels as what Jim will be using? By the way, what are the acceptable fuels now at the EPA testing? 

Another question is how is the WBT used by the EPA different from which version of the other WBT's? I would like a short summary, not just a reference to multi-page documents where the methods are written but the differences are not pointed out. 

BTW, what TLUDs have been tested previously??? 

??? With fans: Oorja (yes) and Reed Campstove (??) and BioLyte (??) and Belonio (??) others? 

??? And natural draft: Peko Pe (?) and experimental unit from StoveTec (yes) and what else? 

Paul S. Anderson, PhD 
Known to some as: Dr. TLUD Doc Professor 
Phone (USA): 309-452-7072 SKYPE: paultlud Email: psanders at ilstu.edu 
www.gtz.de/de/dokumente/ giz2011-en-micro-gasification. pdf (Best ref.) 

Quoting Dean Still < deankstill at gmail.com >: 

Hi Stovers! 

Sorry to have been out of touch. My email was messed up in a subtle way. 

Jim Jetter (EPA/PCIA) is doing a second round of stove testing. He is 
finding out fantastic things about emissions, testing, etc. We are very 
lucky to have such a great guy and activity going on. 

Natural draft TLUDs were shown in the first round to successfully compete 
with fan stoves for low fuel use and emissions. Congratulations to Tom Reed, 
Paal Wendelbo, Paul Anderson, Ron Larson, Christa Roth, etc who invented and 
developed the TLUD! 

To those who are going to submit a TLUD to Jim, please feel free, if you'd 
like, to come to our lab for a free tune up using the emissions hood. 

Strong hot coffee, Fall in Oregon, super low emissions. What could be 

All Best, 


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