[Stoves] Baffle stove for serial TLUD operation Re: Dushanbe Stove

[Paul Anderson]

Crispin,

Thanks for that report about Royal Ocean.  It is good info even if it 
has not progressed into a product of sequential burning of two or more 
TLUDs.

Because we know that height increases length of burn time, in theory a 
very tall TLUD would give many hours of operation.   But TLUDs do have 
(thus far) some physical size limits.   A 200 L (55 gallon) drum/barrel 
is about the largest size that has reported success by various developers.

Back to 2 or more TLUDs in sequential burning.   I like your idea of 
using a paper (or other such biomass material) to get a fire from the 
bottom to go to the top of a different unit.   Could be used in 
conjunction with the gas-channel method that i suggested.   Whatever way 
works, the fire needs to get to the top of the second unit. This is a 
"mechanical" or physical or analog way of igniting, which is what we 
desire because of low cost.   [Elaborate electronic system with heat 
sensors and timers and ignition devices could ignite TLUDs that are 
physically remote, by a foot or mile.   But we are not discussing those 
expensive options until someone with sufficient funding and need steps 
forward.]

I am convinced by the discussion that shared single-walls (essentially 
the baffles concept) will not work well.

Therefore, I am now thinking in terms of cylindrical TLUDs, and maybe 
with double walls, but not required.

And each unit can be handled separately for loading biomass fuel, 
unloading char, and placement into the sequence of serial ignition.

To economically justify the initial efforts, we should be thinking of 
heat for greenhouses, and that means barrel-size (maybe 10 inch -- 25 cm 
-- diameter or larger) units and the ability to have small blowers (12 
volt is fine) and even a few sensors.   Forexample, when a thermocouple 
registers a high temperature (maybe 300 C), a fan/blower for primary and 
secondary air turns on and stays on until the temperature drops to below 
100 C because the batch has been pyrolyzed.

Plan to have plenty of ignition material on the top of the sequential 
units.   When the flame arrives, the ignition should be easy and spreads 
across the entire top of the fuel bed.

If we think of a circle of TLUDs, each one can have a combustor that has 
an elbow to the center where all of the heat is directed as each TLUD 
operates in the series.   Could go to a water heater that gives hydronic 
heat to the greenhouse (already a common feature in many greenhouses, 
complete already with its own pump and  pipes and thermostats).

The user would decide to release or retain the CO2 inside the greenhouse.

Who want to be among the first five to build and test this?   D.H. or 
D.D or who?   I am in, but not alone.

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.com

On 12/5/2015 10:36 AM, Crispin Pemberton-Pigott wrote:
>
> Dear Paul
>
> The idea was tried on a stove called Royal Ocean which is made in 
> Ulaanbaatar. Briefly the history of the company is that a Mongolian 
> guy went to Japan and learned how to make TLUD coal stoves there. When 
> he got back to Ulaanbaatar he reproduced their two cylinder, one 
> chimney stove. He also used the same name.
>
> It was brought for testing sometime in early 2011, in the final, or 
> more final version. As constructed it was two separate ignitions but 
> we (Lodoysamba and the guy and I) discussed at that time how to make 
> one light the other when it burned to the bottom. It was to use paper 
> where you have proposed gas. At that time, the TLUD approach was not 
> fully accepted. The reason for this was the intermittent nature (which 
> was bound to lead to problems) and the inevitable refuelling that 
> would happen with a hot stove (which did and does).
>
> As to the merit of having it automatically ignite, I want to point to 
> something. This does not address your idea of a continuous operation 
> with dead cells being swapped when they are not in use, that is still 
> possible. I am referring the division of the available fuel space into 
> separate zones.
>
> Why do it? What does it offer that is an advantage over a single 
> charge that is either a side draft or a TLUD? One should answer that 
> and be convincing before complicating the process.  What the Royal 
> Ocean stove did was to provide two separate TLUD chambers with a 
> damper system that allowed the chimney to be connected to one or the 
> other. It was a space heating and cooking stove.
>
> Having one light the other when it burned down allows the two to work 
> in series, no doubt about that. It saves the operator removing a 
> cassette and replacing it with a new one so it can burn longer. It was 
> a good idea from that point of view. It was a bit complicated in that 
> it had to have two sets of controls to get a good burn from two 
> separate combustion ports.
>
> If I have a ‘given size’ of fuel loading space, I can’t see a good 
> reason to divide it into smaller sections. One reason could be 
> dropping the power to a low level for a longer time, right? Can that 
> not be achieved without the complication? That is what I am wondering.
>
> In the end the Royal Ocean product had a single chamber. I suspect the 
> power level was inadequate for the physical size, and the cost would 
> have been substantially higher to make and manage two separate stoves 
> inside a single housing. It was impressive to look at and nicely made, 
> but all things considered, a larger single chamber worked better.
>
> A separate question: would the wall temperature of one chamber not 
> overheat/pyrolyse the fuel in the adjacent chamber? Royal had a gap to 
> prevent that, and they had the two separate with no gas connection 
> between them because that would have changed the control over the air 
> flow (over and under air).
>
> I looked around for a photo and only came up with this which is the 
> single chamber version.
>
> I cannot prove anything about why he changed his approach from two 
> chambers in series into one. Likely reasons are heating power and 
> complexity.
>
> Regards
>
> Crispin
>
> Frank and all,
>
> Separate from the coal topic of Dushambe, so I changed the Subject line.
>
> About a Baffle stove:  On 12/4/2015 12:42 PM, Frank Shields wrote: 
> [with my additions in  [... ] brackets]
>
>     One idea [to attain a longer burn time] might be to add a night
>     time insert. That would [from the side] look like a _IIIIIIII_
>
>     with baffles that go almost to the base. The base has fuel [coal
>     is being discussed, but could be other fuel types] spread across
>     the bottom.  You lite [at the bottom] the one close to the door
>     and that burns up quickly but it takes longer to ignite the
>     second baffle and even longer for the third and so on……
>
> Frank, I like the idea of baffles of some type.   Probably done in 
> some ways somewhere maybe long ago, but baffles are certainly not 
> evident in currently discussed stoves and therefore your idea is a new 
> innovation for us 21st Century stovers.
>
> I want to add a further variation for consideration.   It is based on 
> TLUD principles.
>
> Consider a rectangular fuel chamber with several vertical baffles 
> running across between the long side walls  (3 or 4 are sufficient for 
> the concept, but could be more.)   First thought was to have square 
> vertical boxes that are in a row, basically with one side shared by 
> two squares.  (cylinders with obvious spaces is a variation to discuss 
> later).   Call them B1, B2, etc for Box 1, Box 2......
>
> Ignite B1 at the top and let the MPF (Migratory Pyrolytic Front) do 
> its job downward through that fuel, with burning of the created gases 
> at the combustor level.   When the MPF reaches near the bottom, it 
> encounters a hole on one side. That hole is attached to a vertical 
> pipe that is able to receive some (maybe 20%??) of the pyrolytic 
> gases.  (the percentage could increase if the side hole is actually a 
> vertical slit / hole that receives more gases as more of the slit is 
> in the zone of the MPF.)
>
> The gases in the vertical pipe (call it an "ignition pipe") reach the 
> top and are ignited by the existing flame in the combustor.   But 
> those combusting gases are able to move upward into the combustor area 
> of the adjoining box B2.   In that way flame is into the area of B2, 
> and within a few minutes of time B2 has become Top Lit and begins to 
> operate as a TLUD.   The process continues with B1 essentially 
> shutting down (very little draft) and several ways of extinguishing 
> the created charcoal by an operator or even "automatically".
>
> B2 ends and transitions to B3 in the same way.   If the burn-time of 
> each Box is approximately one hour (easy to accomplish with height and 
> with reasonable fuel like pellets), 8 boxes would operate the heater 
> through the night.
>
> Quite literally, the boxes could be in a snake form or in a "6-pack" 
> or 12 pack or spiral arrangement and continue for 12 hours or even 
> longer.   If the boxes were of different cross-sectional areas 
> (different diameters), there could be different intensities of heat at 
> different times.  That is, the five boxes B4 through B8 could have 
> smaller X-section areas and give less heat in the hours from midnight 
> to 5 AM, when B9 could have a larger fire.
>
> BTW, that B9 fire could be under a pot with bath water to be heated 
> and ready at 6 AM when needed.
>
> What is described above is a system for CONTINUAL TLUD operation, as 
> in a serial continual sequence.
>
> This system should work also for larger (such as barrel-size) TLUDs 
> for making biochar AND with heat generation through a long cold night 
> inside a greenhouse.
>
> Of course it can be improved.   And it can have electronic monitoring 
> and the use of fans and blowers that can make the TLUDs respond in 
> many ways.   Such a system can have bells and whistles (figuratively 
> and literally) such as alarms if temperatures go beyond user-specified 
> highs and lows, or digital CO sensors with alarms about the ambient 
> air inside a greenhouse.
>
> Should it be cylinders instead of square boxes?   One advantage of the 
> cylinders is that the vertical ignition pipe can be placed in the 
> natural area where the edges of cylinders are not touching 00000.   
> But shared walls cost less in materials, and the heat through the 
> walls help pre-warm (and pre-dry) the fuel in the next box to be 
> ignited.   But too much heat could cause premature ignition.  These 
> are considerations for experimentation.
>
> So, as of 9:30 AM CST on Saturday 5 December 2015, with the 
> presentation of this message to the publicly accessed Stoves and 
> Biochar listservs, the above ideas are made public.   I believe that I 
> and Frank have some intellectual property (IP) rights for one year 
> after public disclosure.   So if you want to try for patents, etc, you 
> should include Frank and me. But instead, if your work is in the 
> public domain, please feel free to get started.   We want you to be 
> successful.   But we do want to be kept informed of activities and to 
> encourage collaborative efforts.
>
> To move this concept / idea forward, we need some time and funding.   
> We hope that it is YOUR time and YOUR funds, or that you help us find 
> outside funds that can pay for the time and materials.   Frank and I 
> are both retired.   And we do not have the metalwork shops that should 
> be involved with this work.   So we encourage your participation, and 
> please keep us informed of your initial interest (which means tell us 
> SOON), your initial activities, progress, results, and plans for 
> taking it further.   Our email addresses are:    Paul Anderson 
> <psanders at ilstu.edu> <mailto:psanders at ilstu.edu> and   Frank Shields 
> <franke at cruzio.com> <mailto:franke at cruzio.com>
>
> We look forward to the discussion and to any activities. This might 
> all blow over and become nothing.   Or it might be a major step forward.
>
> Paul
>
>

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