<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Bodie, cc List:<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Congratulations on getting as far as you have gotten. I went to the two web sites (I recommend to all) you have below and can see you have been doing all the right things.</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Few thoughts inserted below, and in your list of questions</div><div><br></div><div>
<div class="page" title="Page 1">
<div class="section" style="background-color: rgb(255, 255, 255); position: static; z-index: auto;">
<img alt="page1image568" width="237" height="100" apple-inline="yes" id="4DCFC786-88F8-40FB-9992-CE5AAD87482C" apple-width="yes" apple-height="yes" src="cid:D564DDEB-B7EB-4BC6-9622-BC301C386862">
<div class="layoutArea">
<div class="column"><p><span style="font-size: 13.000000pt; font-family: 'Neutra Text Light'; color: rgb(18.000000%, 45.900000%, 71.400000%)">THE AMRITA STOVE:<br>
A Front-Loaded Natural-Draft Top-Lit Updraft Gasifier
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text,Bold'; color: rgb(34.900000%, 34.900000%, 34.900000%)">Objective
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">The guiding principle behind the Amrita TLUD is to design an
improved cookstove that can be fabricated by the user at no
cost. The design is similar both in materials and construction to
</span><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">the traditional “chulha” widely used in India, which augments its
</span><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">social viability. Additionally, the stove is designed to produce
biochar, a valuable co-product of pyrolytic combustion.
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'"><span class="Apple-tab-span" style="white-space:pre"> </span><b>RWL1: All good, valid objectives. I am most concerned about #2 - looking like a traditional chulha. Most TLUDs have top loading of the fuel or fuel can. But maybe you can make the front load work.</b></span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text,Bold'; color: rgb(34.900000%, 34.900000%, 34.900000%)">Materials and Construction
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">The stove body is fabricated by hand from a mixture of clay,
ash, and fiber. The clay provides cohesive strength, the ash
serves as insulation, and the fiber provides tensile strength. The
combination of these three with water produces a workable mix
which becomes very durable and moderately insulative when
dry. A hollow chamber around the combustion chamber/riser is
packed with ash for insulation.
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'"><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL2: All valid. Some work has been done on loading the clay with sawdust and/or charcoal to get a lower density. I can</b></span><font face="Neutra Text"><span style="font-size: 15px;"><b>’t see the configuration of the last sentence. That riser looks rather short.</b></span></font></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">The primary air enters through 25 holes about 0.6 cm in diameter, evenly spaced across the bottom of the fuel
canister. Secondary air enters near the bottom of the fuel canister under the door (area is about 50 cm</span><span style="font-size: 7.000000pt; font-family: 'Neutra Text'; vertical-align: 5.000000pt">2</span><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">) and </span><span style="font-size: 11pt; font-family: 'Neutra Text';">through a hole in the back (about 30 cm</span><span style="font-size: 7pt; font-family: 'Neutra Text'; vertical-align: 5pt;">2</span><span style="font-size: 11pt; font-family: 'Neutra Text';">). This
air rises through a 1 - 2 cm wide space between
the can and the stove body and then is forced
through a 1 cm wide gap at the top of the
canister where it mixes with the wood gases.
The ratio of primary to secondary air supply is
approximately 1 to 6 by surface area.</span></p><div><span class="Apple-tab-span" style="white-space:pre"> </span>RWL3: I think you can cut the ratio of air supplies down closer to unity. There is a lot of flow resistance in the fuel can. The 0.6 cm holes can be smaller. Repeat on the riser normally taller than you show. One way to use the shorter riser is to strive for swirl; see work of Kirk Harris in last few months - a fan blade shape (not a fan).</div><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">The fuel canister is a large food can (20.3 cm
by 15.1 cm), and the combustion chamber/riser
is a smaller food can (12.7 cm by 9.4 cm).
Primary air enters through a similar food can in
the front, modified into an oblong oval shape.
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'"><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL4: I</b></span><font face="Neutra Text"><span style="font-size: 15px;"><b>’d try a food can taller than 12.7 cm.</b></span></font></p><div><span class="Apple-tab-span" style="white-space:pre"> </span>I suggest a good bit of primary air is also getting in via your large secondary air inlets - unless you have a really smooth surface for the fuel can to sit on. Maybe that “sit-on” surface could be metallic or ceramic.</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>The oblong food can could be replaced with an all clay aperture that is plugged with a wedge. It is not clear how you are plugging that oblong - but you need a ver good plug to control primary air.</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>(more below)</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><p><span style="font-size: 10.000000pt; font-family: 'Calibri,Italic'">Designed by Bodie Cabiyo for Amrita SeRVe, </span><span style="font-size: 10.000000pt; font-family: 'Calibri,Italic'; color: rgb(1.960000%, 38.800000%, 75.700000%)"><a href="http://www.amritaserve.org">www.amritaserve.org</a></span><span style="font-size: 10.000000pt; font-family: 'Calibri,Italic'">.
For more information, contact <a href="mailto:bodie.cabiyo@gmail.com">bodie.cabiyo@gmail.com</a>.
</span></p>
</div>
</div>
<img alt="page1image17328" width="199" height="267" apple-inline="yes" id="D73895DE-771C-4781-B0F6-41DF6CA96A0D" apple-width="yes" apple-height="yes" src="cid:6F534238-C5FD-41CC-8CF0-1680EFF630CB">
<img alt="page1image17936" width="284" height="235" apple-inline="yes" id="EB1146C7-B954-4484-90BF-0CB35277DC3F" apple-width="yes" apple-height="yes" src="cid:44CDC08B-7BD9-473B-84E2-E9C4647CF446">
<img alt="page1image18104" width="88" height="0" apple-inline="yes" id="63573658-EB11-4C39-A3F2-0DD27F57DF84" apple-width="yes" apple-height="yes" src="cid:2FEC8995-6064-476F-B883-F243AB3CFF8E">
</div>
</div>
<div class="page" title="Page 2">
<div class="section" style="background-color: rgb(255, 255, 255); position: static; z-index: auto;">
<img alt="page2image568" width="237" height="100" apple-inline="yes" id="6E4304C0-4D8F-46A0-BEF6-2E9532EB482B" apple-width="yes" apple-height="yes" src="cid:F9249E2F-5B3A-40BB-B460-9410033F9B34">
<div class="layoutArea">
<div class="column"><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text,Bold'; color: rgb(34.900000%, 34.900000%, 34.900000%)">Operation
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">The fuel canister is first packed with small pieces of fuel (about 2
to 4 cm), and a layer of flammable material can be placed on top
to catch the fuel. Otherwise, a few pieces of fuel soaked in
kerosene can be placed on top of the fuel bed. The stove is
started by top-lighting the packed fuel canister and placing the
canister inside the stove body. Whether or not the door is
immediately put in place </span><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">doesn’t seem to make a difference.
</span><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">Once the stove starts to burn strongly, the temperature can be
slightly moderated by blocking the primary air inlet.
</span></p><p><span class="Apple-tab-span" style="font-family: 'Neutra Text'; font-size: 11pt; white-space: pre;"> </span><b><font face="Neutra Text"><span style="font-size: 11pt;">[RWL5: The fact that the secondary air door and the </span><span style="font-size: 15px;">“</span><span style="font-size: 11pt;">slight moderation of the primary air inlet makes no difference is of concern. </span></font></b></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text,Bold'; color: rgb(34.900000%, 34.900000%, 34.900000%)">Performance
</span></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">Starting: Depending on the flammability of the fuel, starting can
be difficult. With coconut shells as fuel, it typically takes 2 to 4
minutes of weak, smoky combustion before the flame reaches a
point where it is sufficient to burn the smoke.
</span></p><p><span class="Apple-tab-span" style="font-family: 'Neutra Text'; font-size: 11pt; white-space: pre;"> </span><b><font face="Neutra Text"><span style="font-size: 11pt;">[RWL6: </span><span style="font-size: 15px;">Can</span><span style="font-size: 11pt;"> you expand in first clause? What fuels give no problem?</span></font></b></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">Mid burn: The stove produces a very strong flame after the fuel
has equally lit and the can is starting to heat up (about 4 or 5 minutes). With high-calorie fuel (i.e. coconut</span><span style="font-family: 'Neutra Text'; font-size: 11pt;">shell), the flame can reach up to 8 inches above the combustion chamber/riser in a vertical column. With low
calorie fuel (i.e. grass and cow dung), the flame is much smaller but still vigorous. Without a pot, the flame
produces no visible smoke and does not cause stinging to the </span><span style="font-family: 'Neutra Text'; font-size: 11pt;">eyes or produce smell. When a pot is placed on top of the flame</span><span style="font-family: 'Neutra Text'; font-size: 11pt;">spire, however, puffs of smoke and a very thin stream of smoke
are produced periodically.</span></p><div><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL7: All these caused I think by too much primary air. The last sentence problems presumably caused by wind,</b></div><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">Transition: If excess primary air is supplied near the end of the
burn, the transition is almost entirely smokeless. The charcoal will
continue to burn slowly and cleanly if left in the stove (though this
is presumably damaging to the fuel canister).
</span></p><p><span class="Apple-tab-span" style="font-family: 'Neutra Text'; font-size: 11pt; white-space: pre;"> </span><b><font face="Neutra Text"><span style="font-size: 11pt;">[RWL8: Again evidence of too much primary. Now your secondary is not being used at all. The </span><span style="font-size: 15px;">char</span><span style="font-size: 11pt;"> is combusting from the bottom. For those of us believing in char, the cook should be making money with this valuable commodity.</span></font></b></p><p><span style="font-size: 11.000000pt; font-family: 'Neutra Text'">Efficiency: The stove will bring 2 L of water to a rolling boil in 12
minutes when placed on the burner after the fire has caught
evenly. The turndown ratio, however, is very poor. At present, the
stove essentially has two heat settings: high and very high. Even
with tiny amounts of primary air, the flame is still very strong.
Total burn time with coconut shell is about 30 minutes and 45
minutes with top-loading (at high heat). The stove yields about 20
to 25% biochar by weight if the char is removed. At any point
during the combustion cycle, the stove body surrounding the
combustion chamber/riser is cool to the touch.
</span></p><p><span class="Apple-tab-span" style="font-family: 'Neutra Text'; font-size: 11pt; white-space: pre;"> </span><b><font face="Neutra Text"><span style="font-size: 11pt;">[RWL9: You may think you have </span><span style="font-size: 15px;">“</span><span style="font-size: 11pt;">tiny amounts of primary air</span></font></b><font face="Neutra Text"><span style="font-size: 15px;"><b>”, but try a design where the 0.6 cm holes are 0.6 mm (maybe too small, but anything to further cut down on primary air). There is excellent recent work on the list from Julien on the impact of these primary air holes.</b></span></font></p><div><span class="Apple-tab-span" style="white-space:pre"> </span>Really glad you wrote in. Best of luck.</div><p><span style="font-size: 10.000000pt; font-family: 'Calibri,Italic'">Designed by Bodie Cabiyo for Amrita SeRVe, </span><span style="font-size: 10.000000pt; font-family: 'Calibri,Italic'; color: rgb(1.960000%, 38.800000%, 75.700000%)"><a href="http://www.amritaserve.org">www.amritaserve.org</a></span><span style="font-size: 10.000000pt; font-family: 'Calibri,Italic'">.
For more information, contact <a href="mailto:bodie.cabiyo@gmail.com">bodie.cabiyo@gmail.com</a>.
</span></p>
</div>
</div>
<img alt="page2image23104" width="194" height="260" apple-inline="yes" id="9F943CDC-65D7-46C4-B476-960A08A2C8CB" apple-width="yes" apple-height="yes" src="cid:1FB9C5F6-6E90-4336-AA64-E1E176739768">
<img alt="page2image23712" width="192" height="257" apple-inline="yes" id="33243561-8E8F-440A-A7BA-0509F670E81A" apple-width="yes" apple-height="yes" src="cid:048975FA-8E2A-4971-B687-4ECDFF613399">
<img alt="page2image24320" width="88" height="0" apple-inline="yes" id="C336E2D6-67D6-4308-BC3C-9F5BADE18B59" apple-width="yes" apple-height="yes" src="cid:044CAC0F-C2A2-4D8D-AAAC-EBFD70A2AD51">
</div>
</div></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br><div><div>On Jan 12, 2015, at 10:06 AM, Bodie Cabiyo <<a href="mailto:bodie.cabiyo@gmail.com">bodie.cabiyo@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr">Hi Fellow Stove Enthusiasts!<div><br></div><div>For the past few months I've been working on refining a TLUD design (attached) which is fabricated from a mud mixture and recycled cans. My intention is to design a efficient, biochar-producing stove that can be fabricated by the user. </div><div><br></div><div>I've gotten the stove to a point where it burns well under certain conditions, but I'm facing some serious roadblocks that I can't seem to surmount on my own. I would love your feedback.</div><div><br></div><div><div style="display:inline-block"></div>Here's the key problems I'm trying to solve:</div><div><ol><li>Weak starting. With my primary fuel (coconut shells), it takes about 2 - 4 smoky minutes for the stove to really get going and start burning the smoke. </li></ol></div></div></blockquote><div><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL10: Some ideas above. Anything like pine needles available for starting?</b></div><blockquote type="cite"><div dir="ltr"><div><ol start="2"><li>Poor mixing. A couple of weeks ago, Crispin described a "textbook example" of poor mixing characterized by a column of flame that produces smoke when the pot is placed over it. I presume that with better mixing, the majority of the smoke would be combusted by the time it gets to the pot surface. </li></ol></div></div></blockquote><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL11: You all need vertical distance to get mixing. Try Kirk Harris’ small fan blade to achieve swirl. Can sit right on top of the fuel. You might also consider filling the fuel can only 70-80% with a set of secondary air holes or slits at that height. Most of use doing TLUD designs have such holes, I believe</b><br><blockquote type="cite"><div dir="ltr"><div><ol start="3"><li>Poor turndown ratio. As mentioned in the document, the stove has two settings: high heat and very high heat. Even with a tiny amount of primary air space, the heat stays very high. </li></ol></div></div></blockquote><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL12: Repeat that I believe your primary air supply is not tiny.</b></div><div><b><br></b><blockquote type="cite"><div dir="ltr"><div><div>I'm eager to hear your comments! What do you think? Can I perfect this stove, or have I created a beast that can’t be tamed? :)</div></div></div></blockquote><span class="Apple-tab-span" style="white-space:pre"> </span><b>[RWL13: Many things done well here. Congratulations on doing a lot of work before writing in. I strongly endorse trying to make a do-it-yourself clay stove - to get the cost to near zero. You might try a parallel approach with a top-loading design - but I recognize that you are trying to make it look similar to the traditional - and that may have considerable value in India.</b></div><div><b><br></b></div><div><b><span class="Apple-tab-span" style="white-space:pre"> </span>I hope others will chime in.</b></div><div><b><br></b></div><div><b><span class="Apple-tab-span" style="white-space:pre"> </span>Ron<br></b><blockquote type="cite"><div dir="ltr"><div><div><br></div><div><br></div><div>Thank you in advance!</div><div><br></div><div>Bodie</div><div><br></div><div>PS. You might notice the absence of a proper WBT. I haven't bothered yet because I feel that I should address the above issues first. If it would be helpful for assessing the design, I certainly can give the results of a WBT.</div><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><b><br><font color="#666666">Bodie Cabiyo</font></b><div><font color="#666666"><b><br></b></font><div><font color="#666666">Professional: <a href="http://carbonalternatives.org/" target="_blank">carbonalternatives.org</a></font></div><div><font color="#666666">Personal: <a href="http://concentricchange.wordpress.com/" target="_blank">concentricchange.wordpress.com</a><br></font><br><u><b><font color="#274e13">Food for Thought:</font></b></u><i><br>"A mountain is composed of tiny grains of earth. The ocean is made up of tiny drops of water. Even so, life is but an endless series of little details, actions, speeches, and thoughts. And the consequences whether good or bad of even the least of them are far-reaching."</i><br>- Sri Swami Sivananda<br><div style="padding: 0px; margin-left: 0px; margin-top: 0px; overflow: hidden; word-wrap: break-word; font-size: 10px; text-align: left; line-height: 130%;"></div><div></div></div></div></div></div>
</div></div>
<span><Amrita TLUD Overview.pdf></span>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br>http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org<br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br>http://stoves.bioenergylists.org/<br><br></blockquote></div><br></div></body></html>