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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Willis, I don’t think that the technology described here:
http://www.jetboil.com/files/Helios%20Tech%20Brief.pdf
would be of much use in the more primitive parts of the world but it is interesting. Backpackers want to carry as little fuel as they can so efficiency is important. I have one of their units which will boil water very quickly.
It does seem that cast iron pots could be made with fins on the bottom and up the sides radiating outwards. The pot could rest on the fins instead of on rocks, etc. If the fins where deep enough, there could be space in the center for a small fire. The heated air would move up through the fins and out which would tend to draw cool air in at the bottom for the fire. That would be somewhat like the draft of a chimney. The cool air moving over the fins at the bottom would be pre-heated which might improve the combustion efficiency. There would probably need to be a base so that the fins would not lose heat to the ground. Or the fins could rest on rocks with only a small area of contact. Just a thought.
As a former kitchen boy, I wonder about clean-up. Even if water were readily available, I might soon be cursing the inventor, especially if the cook burned the stew that evening. I now have twice the surface area to clean.
We cooked a one-pot supper for a family of six on a tiny camp fire in a hole in the sand while on the way to Ayers Rock in the NT of Australia back in 1984. A strange couple in a massive converted school bus camped near us. They used a moped to drag back a huge chunk of dead tree, lit it, and left it smouldering overnight, and left it still smouldering (under a live tree and surrounded by spinifex) when they departed the next morning. We felt we had to extinguish the remnants before our own departure. The lesson: with care you do not need to use much fuel to cook for a family, even without a stove.
The further lesson, of course, was that there are always wallies around who do not care for the environment, and for whom wastefulness and pollution are a way of life. We were absolutely staggered at their attitude. It goes without saying that they also polluted the environment with their loud radio and ghastly muzak.
John from CA said: “As gross as this sounds, why not use human waste to generate methane and use the methane for cooking?”
A good idea. In Nepal, India and China and elsewhere human and animal waste is made into gobar gas.
the Dakota hole fire place is much simpler. No special pot to carry and very efficient.
The side chimney turns it into a blast furnace. It was used to keep wild fires from spreading on the plains in high winds. We used it to boil( with a grate on top) or to bake (putting the dutch oven inside) many years ago when I was on the staff at Boy Scout Camp in northern Minnesota.
John Marshall says:
May 10, 2011 at 3:03 am
If by “these” you mean Kelly Kettles, yes, you are right. If you mean a cookpot like I imagined, I don’t think so.
Sure, that would be better, much better. And it would be better if the impoverished people lived in nice houses and had good food and medicine and proper schools. And ice cream. Lots of ice cream …
Meanwhile, in the real world, the sad truth is that we can only advance one step (or one stove) at a time. Installing an electricity grid for an entire country sounds good, but the emphasis is on “sounds”. That’s a long, long ways from today. So I leave such lovely armchair fantasies to folks like yourself, I’m more interested in actually doing something practical for today.
w.
Mr Lynn says:
May 10, 2011 at 5:32 am
Nope. You can’t boil potatoes in a Thermette, but you can in my magic cookpot …
w.
wcp2 says:
May 10, 2011 at 6:15 am
That all sounds great in theory, wcp2. But in practice, when a woman is walking five miles a day in search of a few sticks and twigs, fuel efficiency becomes hugely important.
You should travel around the parts of Africa that have been nearly denuded of wood, and think about the picture. “Buy you a couple of meters of wood”? Sure … if there were wood around to buy. Your theory is the third world equivalent of “let them eat cake”.
Finally, even poor folks understand the importance of running cost, and how it may be much more important than initial cost …
w.
jack morrow says:
May 10, 2011 at 6:15 am
People buy cookpots today. Why would they not buy a cookpot which hugely increases fuel efficiency? Sure, it will be out of the price range of some.
But that is true of anything and has never been a reason to throw up our hands and declare something a “crock”.
w.
Methane from human and animal waste? Nope. Not enough methane made to be worthwhile. You do make enough to run a waste solids digester, but not enough to return it to a city. And there is a bunch of H2S you have to remove.
Michael J. Dunn says:
May 10, 2011 at 7:57 am
No can do, and I’ve put the design out here specifically to prevent people from patenting it. To patent it they have to show that they thought of it first, that there is no “prior art” … and if it’s on the internet that’s gonna be real tough.
w.
Carl Brady says:
May 10, 2011 at 8:01 am
Indeed, and you should be able to use a cookpot like the one I drew above to improve the efficiency of your average stove.
w.
Tallbloke, awesome photos. I love the undying ingenuity of the human species.
w.
Might be wrong, but I believe this has been done in Vietnam for centuries and is used to cook dish called “Luo?”. Bowls of water/wine surrounding a central column containing rising heat from the source located in a ventilated pan at the bottom.
Probably a derivative of the Chinese tech noted in an earlier post…
=8-)
I love this blog. Which would be more efficient- a thermette or a rocketstove? I am not familiar with thermettes and I know rocket stoves can vary based on insulation and materials used. But would anyone here have a rough idea?
Michael J. Dunn wrote (snipped): “casting a novel idea afloat on the internet may only provoke the unscrupulous to capture it and attempt to patent it”
My understanding of patent law (which could be written in five lines on a small piece of paper) is that things that are self-obvious or already known to the public can’t be patented. They have to be new and original to be patentable.
IanM
Russians will declare a samovar to be their “national heritage device,” and demand a huge royalty from anybody trying to sell anything resembling it.
This kind of artifact will be needed massively in the future, if politicians succeed in their green policies….
I see the rocket stove was mentioned above by a couple people.
Another resource:
http://www.rocketstove.org/
How to build:
And a demo video!
Better start handing these out in the UK. It will be thing folks can afford once the cost of wind power hits home.
But that is true of anything and has never been a reason to throw up our hands and declare something a “crock”.
If it were, would that make this a crock-pot? =)
Thanks, Willis! I’ve long been a big fan of these simple, aluminum solar cookers;
http://www.sunoven.com/about-us.php
However, no sun = no heat! Problem solved. Your proposed scheme reminds me of an industrial steam-tube boiler with economizer for waste heat recovery (namely, soup/stew).
Lesson: there is no “one size fits all” for these gadgets, and developing countries could use a mix of low-cost technologies. This will save resources & lives, as indoor pollution load from particulates (generated while burning kerosine, manure, wood etc.) is a huge problem for those folks. Keep up the good work!
Another Gareth says:
May 10, 2011 at 8:43 am
John from CA said: “As gross as this sounds, why not use human waste to generate methane and use the methane for cooking?”
A good idea. In Nepal, India and China and elsewhere human and animal waste is made into gobar gas.
=========
Thanks Another Gareth, very interesting read.
In stead of the pot holder you have on top, make it a grill. You could still place a pot on it, but could also grill without the pot.