Guest Post by Willis Eschenbach
This one is for fun and also for real. The theme of this post is “There’s never enough time.” I worked in the villages of the developing world off and on for a number of years. A recurring issue is the inefficiency of most stoves. The simplest is the “three stone” variety, made with three stones to put the pot on.
Figure 1. An obviously ancient three-stone fire with a modern cookpot in Tanzania. Photo Source
This is hugely wasteful of fuel, particularly in lands where wood and even branches and twigs are scarce. Among my known defects is that I’m an inventor. Over the years I’ve worked on making and designing a variety of stoves to try to improve stove efficiency. As a result, in one of my peregrinations around the web a few days ago I was intrigued to stumble across the “Kelly Kettle”.
The Kelly Kettle was used in Ireland by the shepherds to brew their cuppa tea. Here’s one at work on a beach somewhere.
Figure 2. Kelly Kettle cooking on a beach. Note the fire coming out the chimney.
The brilliance of the plan is that the water in the kettle surrounds the fire. I looked at that, and my inventor’s soul rose to the fore, and I thought “Man, I could make the radical Dutch Oven using that plan. Here’s what I think it might look like.
Figure 3. What I call the “Magic Cookpot”. Note the split (two part) lids, one of which has been removed, flipped over, and laid on the ground for clarity. Lids will have handles in the final version.
And here’s a cross-section:
Figure 4. Cross-section of Magic Cookpot without the lids.
No good to throw away waste heat, so the Kelly Kettles have a pan-holder that fits in the chimney to allow you to cook another pot of food on top.
Figure 5. Kelly Kettle with cookpot. Source.
Looks good to me, so here’s my version of the same. This would allow you to cook soup or stew and have a frypan on top …
Figure 6. Potholder inserts into chimney of Magic Cookpot.
OK, advantages of this plan:
• Efficiency, efficiency, efficiency. Even without cooking anything on the top, this will heat water with less fuel than any design I’ve ever seen.
• Cost. Because the stove and the cookpot are one, you don’t need to buy both.
• Portability. It can be moved easily.
• Adaptability. It can use a variety of fuels, including a propane burner.
• Speed. It will heat water fast.
As I mentioned, the theme of this post is the theme of life—there’s never enough time.
In a perfect world, I’d take this idea and run with it and make a big difference in the amount of wood burned around the planet. I don’t have time, I have a bunch of other projects going on. But I’d hate to see this idea die, it’s a really good one that could make a big difference. So I figure I’ll cast the idea free on the web, make a gift of it to the world of stoves, and see what becomes of it out in the greater marketplace of ideas.
How could this rough plan be improved? It needs a damper to control the draft, and some kind of flap to control the air intake. You could probably increase the heat transfer (fire to liquid) by putting some spiral fins up the chimney. This would increase the surface area and transfer extra heat to the cookpot.
In any case, there it is, and I encourage anyone with the time and energy to become the champion of the idea. You’ll make a name for yourself and have women blessing you all around the planet. All it needs are a couple of sharp Brazilian or Indian or Chinese (or European or American) college students who’d like to make a difference in the world.
w.
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Nice and good looking. “Form follows function.” But for emergency water purification or even routine camping, it probably wouldn’t pass the Environmental Impact Assessment./sarc [Me, I really don’t care any more, given the “quality” and politicization of Central Governmental services. I’ll look after the “environment” myself.]
A circular cross-section of the chimney presents the least possible surface area in contact with the water. You can increase that by flattening the internal part of the chimney while maintaining the same cross-sectional area.
Gas water heaters have a baffle in their internal chimney that causes the flue gas to swirl and bring hotter core gas to the contact surface. It’s a simple strip of sheet metal that has spirals and ripples stamped into it.
An excelllent design and always enjoy your posts.
While AGW receives a lot funding for uncertain future risks, spending a small amount on technologies that people use daily could have real benefits. Given the world’s use of dung, wood, and charcoal, a more efficient stove could have dramatic health, energy, and the environment impacts today.
A Franklin Energy Project to unlease the creativity to design a new Franklin Stove may be a way to achieve that goal. The Franklin Stove was considered revolutionary and it dramatically increased energy efficiency and safety. Like you offering your stove design to the market, Franklin felt his was a public good and he also made it available to all. (Bet you haven’t been called Franklin in a while?)
Coincidentally, I learned yesterday in October 2010 at the Clinton Global Initiative, Hillary Clinton pledged $50 million dollars to a UN sponsored Clean Cookstove initiative. Julie Roberts is the Ambassador and it seems to have become both a government project and a Cause Celeb. A review of the program announcement
(http://aidwatchers.com/2010/09/what-hillary%E2%80%99s-cookstoves-need-to-succeed/) had lots of comments, primarily from former Peace Corps members, that were generally negative on the whole idea primarily for two reasons. The design had to meet the cultural needs of the local cooking style and it had to be really cheap, possibly made of local materials by locals. Past efforts had failed in both of these areas. Any thoughts you or others may have on those comments or ways to advance this worthy cause would be greatly appreciated.
I wonder what Ben would have thought of AGW?
OMG that’s brilliant.
I have anecdotal evidence of how heating from the inside is much more efficient. I make metal electroforms over hollow plastic patterns and the patterns have to be removed from the inside when completed. You have to work really hard to heat the metal from the outside to soften the inside pattern but if you can get some steam on the inside of the form, everything heats really rapidly. The Kelly stove looks like a great way to use fuel much more efficiently and in my experience, heating from the inside out is much more effective.
Willis
Tom Reed developed a micro-gasifier “Woodgas” cookstove with 40% efficiency – the highest efficiency I have heard of.
That is waiting to be mass produced for 3rd world use.
His The Biomass Foundation is the best source of publications on biomass combustion, and gasification.
Great post, and you got me thinking!
I took your idea and ran a bit with it (it’s a 3D PDF – click on the image and you can rotate, zoom, and pan):
1. Added an air insulation layer on the outside to better insulate the hot water/liquid section.
2. Contoured the inside chimney to shape like a chiminea, a very efficient shape for drawing constant air through a fire.
3. Added a small lip to the half-lids, so you could use them to keep things warm over the hot water.
4. Added internal radiators to better couple the liquid to the heat in the center.
The top would work the same as you showed, or you could use a small insert “frying pan” attachment that would route the heat across the base and out the sides, and end up cooking like a wok (from the center and sides as the fire wraps around the pan).
DocD,
That’s called, surprisingly enough, a “hot pot”. Usually one side has a spicy, fiery pepper based broth, the other has chicken or mushroom broth, to give you hot and mild. Then you bring it up to boil, dunk in thinly sliced meat and vegetables, and in 20 seconds you can eat!
Willis: you are missing something very important – all the IPCC’s witch doctors are convinced that increasing global temperature of 0.007 oC p.a. (Gistemp 1900-2000)is quite enough to boil some 3 billion kettles of water a day and generate enough water vapor to raise the climate sensitivity for a doubling of [CO2] from 1 oC to 3 oC or even 6 oC.
Thats very nice but as I recall during my service in Her Majesty’s Armed Forces in the dim and distant seventies we had something very similar (very crude construction by comparison) called a Benghazi, and from what the oldies told me they had been in use ever since the war in the desert in the forties.
I have used a thermette since the 50s. They are incredibly efficient at boiling water with a minimum amount of fuel in almost any conditions, rain, wind etc.
My lady is Thai and they cook outdoors some times like we have BBQ’s. They use a simple earthen ware pot with feet and holes in the bottom as a grate. A couple of hand fulls of charcoal is the fire. Atop this sits an annular pot full of water, the central chimney is grated. The vegetables are cooked in the water and meat strips cooked on the chimney grate. Two hand fulls of char coal I have seen feed ten people, then when ever one is fed the coals are tipped out and doused with water, any charcoal left is used next time. I have eaten in deepest China in an old fashioned restaurant where these are built in to the table and you cook your own food. Very efficient. Your cooking device is excellent Willis but too high tech and needs to be 17th century to make a difference. so that the local artisans can make it easily.
http://wildstoves.co.uk/wood-cooking-stoves/rocket-stoves/g3-rocket-stove-envirofit/
Here’s a stove that works just on kindling. We bought one in case of power cuts, plus a pot to go on top.
Also there’s a small UK charity called Appropriate Technology Asia which helps marginal peoples with simple technology including a cooking stove that does not need timber for fuel.
http://www.atasia.org.uk/web/default.aspx
good one Willis.
the Thermette seems to have it already done though.
you know, why isnt ANYone asking why?
there are so many folks who havent progressed past 3 rocks?
I mean come on, a few handsfulls of mud and some more rocks makes an efficient oven that warms, and chimneys are easy to make with mud and even a hollowed ceiling to let smoke escape was invented cenuties ago.
the smoke preserves seeds and food and deters mozzies so maybe? thats why they are willing to keep doing this?
now if Gates and all the other bignoting zillionaires really wanted to help..theyd run a education and supply of similar useful things. will they? doubt it.
This is why I love reading at WUWT. Can-do attitude where a low-tech but highly practical invention DOES deserve attention here! One cool technology I have always thought about that might work any country are water powered clock mechanisms. You could water power the solar tracking for photovoltaic systems or solar furnaces. Thanks for this neat invention, it may end up helping the world, we should call it the Eschenbach Crock.
All very fine and all very well. I have no problem with improving the state of the art and health of humanity. Problem is that some people latch on to this and run the wrong direction with it. In specific I am talking about (Robert) Jeremy Grantham of GMO LLC. who wants to put a carbon tax in to finance these in 3rd world countries.
Willis
The tsotso stove came to mind http://www.newdawnengineering.com/website/stove/singlestove/tsotso/
Google it for more info and other evolutions and other ideas. http://bioenergylists.org/en/maputojoao
Great thread! You seem to have reinvented the Thermette, but I was delighted to learn about that. Will send a link around to family members who are campers and hikers (and even a ‘sustainability’ nut or two).
Don’t disparage the three-stones method, though. Nothing is easier when traveling. You don’t need to tote anything except a pot. The only challenge is to find some stones, and some dry tinder and sticks.
/Mr Lynn
Here is another version:
http://www.littlbug.com/
One of the reasons I read The Chiefio’s blog is because I love the survival stuff. It just might come in handy one day, but NOT because of global warming. Thanx Willis and posters.
Good post, Willis, and seems to have got the creative juices and the memories flowing.
Like most Kiwis, I grew up with the Benghazi Boiler which later became the Thermette. Almost every family had had one of these for a hot cuppatea on a rural job or at the river/beach/down the back of the family farm before barbecues became universally popular.
If your updated design were to be made by village craftsmen, I would suggest that using ceramics (fired mud) as a construction material may put the device within reach of a huge consumer group.
I just don’t see how you can get the production costs down low enough to be price competetive with the 3 stone model pictured in the article. 😛
If I missed it I apologise, but I couldn’t see any place to start looking for similar devices in the UK.
What I would like to source is something like a 20 litre (4 gallon) catering urn.
Or better the Eschenbach Crock Pot.
Some nice stoves here, but don’t forget the simplest way to make a fire more efficient: dig a small straight-ish sided hole, and build the fire at the bottom. Then simply put your pans on top. Nowhere near as efficient as surrounding the fire with working fluid, of course, but if you’re calculating efficiency improvements, you should start from the baseline of what’s easily achievable with a little thought but no additional resources.