RE: Brick TLUD

From: K McLean <kmclean56@gmail.com&gt;

Sent: Monday, October 23, 2023 7:50 AM

To: Ronal Larson <rongretlarson@comcast.net&gt;

Cc: Joshua Guinto <jed.building.bridges@gmail.com&gt;; dan weinshenker <danweinshenker@gmail.com&gt;; Kirk Harris <gkharris316@comcast.net&gt;; Bill Knauss <wmknauss@gmail.com&gt;; Andrew Heggie <aj.heggie@gmail.com&gt;; Anderson, Paul <psanders@ilstu.edu&gt;

Subject: Re: Brick TLUD

Clement tested with rice straw and bagasse.  Both work great.  Hot and little smoke.  It’s clear that the stove works with most biomass that isn’t too small like sawdust and rice husks.

Jed et al

 

See inserts.

On Oct 17, 2023, at 4:51 PM, Joshua Guinto <jed.building.bridges@gmail.com> wrote:

 

Dear All 

 

Sorry for my episode of silence. I have undergone an episode of anxiety and then a series medical check up. My years of overwork and stress is catching up as i am not getting younger. 

 

[RWL:  sorry to hear this.  I (sure all of us) wish you good luck.

 

I read every bit of the email exchange and hereby share with you bits of update. 

 

We now have the complete set of the clay slabs done. Three sets were done. The fourth set will be for the chimney and pot rest. They are now drying in the solar dryer. 

[RWL;  Good to hear.   Keep us informed on progress.

 

Thanks Kevin for pushing in with the stacks of bricks. We are one in this path. i have done a lot with stacking bricks to create something new and cheap. 

Kevin is reporting prices for new (I thought only old) of less than 4 c per brick  (not every where). I think for metric sizes relatively near the US 2’ X 4” X 8”.  I think one more like 3 x 3 x 8 might be better for stoves.  How do
your clay slabs compare?

 

While the clay slabs are still drying in the greenhouse dryer. there is a stock of firebricks here which we can use to tinker and create something interesting. 

[RWL:   Wonderful.    The surprise to me in Kevon’s work is that all secondary air is coming from the top of the top-most layer.   Seems to work well, but maybe could better come from one or two layers lower.  Or even from the vertical
spaces between bricks.  

This should be relatively easy to test.   But we need a good way to test emissions in the field.  I’ve read of low cost meters and will try to locate.

 

` Thanks for the report.

Ron

 

 

Will let you know in a few days. 

 

 

Jed  

Joshua B. Guinto

Specialist, Appropriate Technology

MSc Management of AgroEcological Knowledge and Social Change (MAKS)

Wageningen University, The Netherlands
2006 to 2008

Recipient, International Fellowships Programme  Award (IFP) 2005

Ford Foundation

 

 

 

On Mon, Oct 16, 2023 at 12:41 PM Ronal Larson <rongretlarson@comcast.net> wrote:

Hi all:

 

1a.  Here is one possibly helpful modification (bottom half) of what (top half) Kevin and John have been testing:

 

<Screenshot 2023-10-15 at 9.00.26 PM.png>

 

 

b. Takes one more brick.  Found many other ways – some could add more loadable biomass and char – but this is easiest with present model.  I hope John (anyone) could try it out and see if the bottom approach is easier for cooks.

 

c.  Kevin has talked of pushing char out.  Easy to add an opening at both ends – with either the top or bottom approach above.

 

d.   After doing this drawing. I realized that the two brick sides (left and right above, not top and bottom) could be moved sideways as well, and would not need the added brick.  And drooping of the single bricks above maybe wouldn’t be
a problem, as there would be only one brick above, as long as the opening was restricted to maybe a 6” or 7” opening – not the full 8” of the above lower sketch.  Sorry I have no sketch on that yet;  I’ll try to add that.  Could be a better approach.

 

e.    Joshua might be able to do this with many fewer parts – with cast biocrete or fired clay pieces.  Can his cost be acceptable?  The present Kevin design is going to be hard to beat on cost grounds.

 

2.  Dan today sent a nice NYT (biochar) pertinent article – see 

https://www.nytimes.com/2023/10/15/business/nigeria-fertilizer-shortage.html?smid=nytcore-ios-share&referringSource=articleShare

How a Fertilizer Shortage Is Spreading Desperate Hunger

 

Kevin’s new brick stove design could help a lot.

 

3.   Any comments on how to help Kevin move faster with this new approach?

 

 

  Few comments below on Paul’s note from yesterday.

On Oct 14, 2023, at 10:24 AM, Anderson, Paul <psanders@ilstu.edu> wrote:

 

Kevin,

 

I want to add support to all that Ron wrote.  

 

Adding  more layers of bricks is a nice option to have and to test.   More on the fuel-zone will increase burn time.   More on the “riser” will help accomplish better combustion of the gases (lower emissions). 

[RWL1:  Agree.  But I’m still impressed that the needed secondary air seems to be nicely coming down (uniformly on all four sides) from the top – not the usual horizontal secondary air input.  This may be so good as to
not need more top-most fuel-empty layers.  One may be just right.

 

Char yield is to measured and studied, but anything from 15% to 25% would be fine as a goal.

 

With 5 liters (5 kg) of water in a “Standard” stainless steel pot has these water boiling times:   (based on many years at Aprovecho Stove Camps;   Others can confirm or present alternative comments/times)

RWL2: And the Apro approach is based on international standards.  The US stove standard group met this past week – and the ISO standard seems to be final now (maybe 10 years struggle?).  Has 4 parts.  The handling of char seems fine
(was in dispute for awhile), but “intentional biochar” is totally absent.

 

Under 10 minutes:  very fast; overpowered

[RWL3:   I think 10 minutes would be OK if TDR (turn down ratio) is large enough.  Everyone wants fast boiling.  How big can this TDR be?

 

15 to 18 minutes:  Quite good

 

About 20 – 22 minutes:   a bit slow

 

Over 25 minutes:  too slow;  pot is losing heat and thermal-transfer efficiency is low

[RWL4:  It seems to me that the 8” x 8” (in English units) is a pretty darn good choice.   Mostly under 15-18 minutes.

It is not so easy to get  9’X 9” etc, until you get to 12” x 8”. 12” x 12”, etc.

Kevin’s 6 bricks per layer looks very safe, but I wouldn’t be surprised to find something cheaper.   

I’m still wondering if the thin, more vertical brick orientation might work.  Would save half the bricks.  

Maybe cement is needed?  

I used to think one needed lots of secondary air holes on the four walls;  not now.

The problem still needing further study is how best to get the finished char out.   A basket may still be cheap enough.

 

Kevin wrote about failure of the 4-bricks-per-layer stove, with 10 x 10 cm opening.   100 sq cm is rather small for TLUD cooking.   Equivalent to 5.6 cm radius (11 cm diameter = ~4 in diameter), that can be fine in forced air (FA) TLUDS,
but seldom seen in natural draft (ND) TLUD stoves.

 

BUT might work if the stove had more height, both for fuel and for riser. 

RWL5:  I doubt we’ll see value for this small a stove cross-section..

 

Better suggestion would be to have bricks with curve on one of the “inside” sides to help avoid the “cold corners” where the temps and drafts could be different. 

 

The use of segments of elephant grass is GREAT.   We hope to hear more about that fuel in TLUD stoves.

[RWL6:  Grasses (there are many others) not much used now.  Less dense than wood, but now can be burned with much less smoke  than if burned in the field and much time savings and money earned and crops improved.

 

Question is how to get carbon credits – so new companies can be involved in getting this type of stove in wide use.They can’t make money on stoves this cheap, but they can with the char, it would seem.

 

Also can be used in urban settings it would seem.  Must be cleaner and much better economics than sending char into cities.  I feel that all produced char must be used in Ag crop fields with both yield improvements and CDR-payment improvements. 
No one should ever burn char.

 

Ron

 

Paul

 

Doc / Dr TLUD / Paul S. Anderson, PhD 

Email:  psanders@ilstu.edu       Skype:   paultlud     Mobile & WhatsApp: 309-531-4434

Website:    https://woodgas.com see Resources page for 2023 “Roadmap for Climate Intervention with Biochar” and 2020 white paper, 2) RoCC kilns,
and 3) TLUD stove technology.                       

 

From: Ronal Larson <rongretlarson@comcast.net> 

Sent: Friday, October 13, 2023 12:41 AM

To: K McLean <kmclean56@gmail.com>

Cc: Joshua Guinto <jed.building.bridges@gmail.com>; dan weinshenker <danweinshenker@gmail.com>; Kirk Harris <gkharris316@comcast.net>; wmknauss@gmail.com;
Andrew Heggie <aj.heggie@gmail.com>; Anderson, Paul <psanders@ilstu.edu>

Subject: Re: Brick TLUD

 

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Kevin and all: 

 

Sorry for delayed response.  Have had a most unusual day.  Sold our house (officially – with a title group involved) finally today

 

I talked with Kevin earlier today (before seeing the video) so have had perhaps a bit more background for the following .  

One thing missing so far is that there are no intentional entry ports for secondary air.  I am inclined to believe that all the top layers above the fuel load would work good if as leaky as possible.  There should be no danger of flame
exiting the stack sideways.  Maybe better to have at least two of the top layers without fuel?  (At the expense of shorter run time – but could add a seventh layer.

Also that the initial fuel loading was always up through five of the six layers of brick.  I’m having computer access problems so I have not been able to view the video as often or closely as I would like.  It would be interesting to know
more about the timing on this video and what the specific fuel loading was (vertical or horizontal etc.)

Paul has expressed concern on horizontal loading – (because it takes longer to load I think).  But I’d like to hear more on char yield etc., Longer run time may be a quite desirable virtue

The cost of the bricks can be less than 5 c each.  So this seems clearly likely to be perceived as cost effective – which has apparently been THE reason for minimal adoption by 3-stone users.

All of my thinking on this design has been for edgewise bricks, so 6 layers would have been twice as tall.  Will be interesting if we can find a way to make them sufficiently stable

My recollection on speed to boil is that 9 minutes is exceptionally fast.  Maybe excessive power? (Are there other videos that might tell?)  Would be helpful to see more videos with knowledge of the fueling type of loading. 
Anyone remember boil times for other TLUDs?  I’ll bet Kirk and Bill have some numbers to share for a 4 liter pot..

I think I see a different way to control primary air at the bottom layer.   And will work on that.  The idea of opposite entry points for “pushing” the produced char out (rather than pulling) seems novel and helpful.

Kevin – could you ask John where the whistling noise seemed to emanate?  I don’t recall any other TLUD report with a whistling noise.

 

I’ll try to add more when I can look more closely at the video.  And look at other comments.  There is still a lot more to learn – especially on these new fuels – and Mormon char yield and what preeent 3-stone users (not John) are involved. 
And we have more data on yield.  25%?

 

Ron

 

 My conclusion is that all the bricks

 

On Oct 12, 2023, at 11:34 AM, K McLean <kmclean56@gmail.com> wrote:

 

I’d like your thoughts on this cookstove for Africa.  We are also testing a smaller cookstove (4 bricks per layer) but the same principles apply.

 

<image.png>

 

In this configuration, each layer has 6 bricks.  There are 6 layers.  The bricks used in Uganda for testing are 6x12x22 cm.  So the height of the stove is 36 cm and the fire chamber/chimney is 22×22 cm.

 

Two bricks are removed from the bottom layer for air holes.  These bricks are also used to partially block the air holes to turn down the heat.

 

We mudded in the sides.

 

Fuel is put in a pile from the top and lit on the top.

 

We tested today with:

– elephant grass stalks, horizontal and criss crossed.

– elephant grass stalks, vertical

– maize cobs

– cow dung sticks, horizontal

 

All four tests were very successful.

– hot (9 minutes to boil 4 liters of water, except horizontal stalks took 16 minutes)

– very little smoke

– about 30 minutes burning without tending.

– made “a lot” of char.

– John (the tester) thinks the stove is efficient but we don’t have anything to compare to.

John could hear the rushing air.  His reporting on turning down the heat by blocking the air hole was not consistent.

 

We are both extremely happy with the testing.  This should work with almost every fuel except small fuels like sawdust and rice husks.  Simple and cheap.

 

<image.png>

 

Here is a video.

 

Over the next few days, John will test more fuels and test a smaller stove (4 bricks per layer, 6 layers, 10×10 cm fire chamber/chimney).  With and without mudding.

 

What are your thoughts?

 

Kevin