Efficiency

I recently discovered these aluminum cookpots with stubby rods welded to the bottom to act as fins. These should improve heat transfer to the cookpot.

http://stores.cajunrocketpot.com/-strse-Cajun-Rocket-Stock-Pots/Categori...

Cajun Rocket Stock Pots
4 mm Aluminum Professional Cookware. All our stock pots come with lids. Great for reducing, cooking, frying & boiling stocks, soups, gumbos, potatoes, seafood, pasta, ... Reduces cooktime and fuel usage, saving you time & money. Abosrbs more energy from your burner & distributes that energy more evenly throughout the cooking process. Length dimensions include handles

ove Camp 2013 ----- July 22-26,2013 ----- Cottage Grove, Oregon

“Great Stoves” to meet the Global Alliance standards for clean, efficient, and safe cooking.”
Co-hosted by InStove, Aprovecho Research Center, and Paul “Dr. TLUD” Anderson
The Global Alliance for Clean Cookstoves is establishing standards, and this summer’s stove camp is going to focus on the design and delivery of stoves that meet them. We will be looking at the various proposed tiers of stove performance and see which stoves fall into what classifications. We’ll also be exploring design considerations for producers who are interested in building top-tier stoves.

Schedules will be available in early June.
For details, email Stella Strother-Blood at: Stella@instove.org. or Mike Hatfield: apromike@gmail.com

Registration: Mike Hatfield: apromike@gmail.com

The "Easy 5 Gallon Bucket Rocket Stove", is very easy to build. All materials anyone needs to cook a good hot meal is a metal 5 gallon bucket, some stove pipe and vermiculite, pearlite or similar insulation (even "wood ash" can be used). Since the insulation separates the heat from the housing, almost ALL of the flame and heat is directed up to the cooking pot or utensil. Almost NO heat is wasted, making it one of the most efficient rocket stoves I've seen. Definitely one one the EASIEST to build and transport!

Ron Ray

Stoves Camp 2010, Cottage Grove Oregon

Stoves Camp ParticipantsStoves Camp Participants

Fifty two high energy participants attended Stove Camp this year at Colgan’s Island, camping near the river, making and testing stoves, and listening to Fred’s Big Band harmonize so beautifully. Fred and his volunteers cooked breakfast every morning and dinners at nighttime parties on Rocket and TLUD institutional stoves.


Nick Salmons from International Lifeline Fund made a very successful Haitian charcoal stove that was voted “Best in Class” by his peers!

Stove Camp provides a venue for a gathered scientific community to advance knowledge of biomass cook stoves. Participants made new stoves and tested them daily for fuel use and emissions. Every morning the test data was shared and new stoves were constructed.

This year, a great deal of progress was made on charcoal stoves for Haiti. Camp participants, some of whom have worked in Haiti,designed a two-hour Water Boiling Test for Haiti, which uses a Haiti pot
and mimics a typical cooking task, cooking rice and beans. Charcoal stoves were constructed that used less fuel and produced less carbon monoxide compared to traditional Haitian stoves.

See the attached Stoves Camp Report for details of the tests, the interesting findings about the optimum charcoal to use for each stove, and pictures of the stoves tested.

Save Money, Save Energy, Eat Well!

Since the introduction of our line of Cookswell Energy Efficient Charcoal Ovens in 1992, thousands of ovens have been sold regionally and countrywide, to all manner of people for all manner of uses.

Finned Pots as a Means of Increasing Efficiency Dale Andreatta, Ph.D., P.E., dandreatta@sealimited.com, February 13, 2009

Finned PotFinned Pot

Executive Summary A pot with heat transfer fins has much greater surface area than pots with no fins. In theory, this could lead to greatly increased heat transfer to the pot for a given stove, and the pot would theoretically improve the performance of the stove under all conditions. While we often concentrate on the stove as the primary element of a cooking system, the efficiency of a stove is mainly determined by the heat transfer to the pot, and designing a better pot would be an easy way to make a more efficient stove. A variety of types of finned pots were built and tested. The best designs were separated out in the lab, using natural gas to simulate a wood flame. Several types of fins can be retrofit to existing pots. The better designs of finned pots performed well over a range of conditions using simulated stoves, and sometimes also with an actual wood burning stove modified to use natural gas to simulate a wood flame. With fins on or near the bottom of the pot the finned pots typically gave around a 1.76-fold improvement in heat transfer. If the fins were on the sides of the pot a greater than 2-fold improvement was achieved. Tests on actual stoves using wood as the fuel generally gave smaller improvements in performance, generally 1.33 or less, corresponding to a 25% or smaller reduction in fuel usage. These tests were done under a variety of conditions with a variety of stoves, including the open fire (3-stone fire). On industrial fuel stoves using kerosene or alcohol, improvements were even less, with the finned pots giving 1.2 fold improvements or smaller. In some tests the finned pot used more fuel than an unfinned pot. The reasons for this wide range of results is not known. It is not recommended that finned pots be pursued as a means of increasing the efficiency of stoves. Better results can probably be achieved with less effort by using skirts around the pot. These skirts could be attached to the pots with optimum dimensions. See attached report presented to ETHOS 2009

“How-To Designs” and Lanny Henson presents,
The “Green Pail”/“Hot Bucket” Retained Heat Cooker.
April 20, 2008
gp05

Insights Into Fuel Efficiency and the Dissemination of Mud and Ceramic Stoves in Southern Africa
Peter Scott, Biomass Energy Consultant, December 23, 2007
Lorena 2 Pot 2003Lorena 2 Pot 2003

Shielded One Pot 2003Shielded One Pot 2003
Dear all

I wanted to offer a couple of brief insights into the recent dialogue regarding fuel efficiency and the dissemination of mud and ceramic stoves in southern Africa

First, A little back ground:

I worked with GTZ-EAP in Uganda for 3 weeks in August of 2003 . During that time I built a number of metal and brick stoves - both household and institutional - as well as bread ovens and a number of insulated ceramic combustion chambers . I didn't design the 2 pot Lorena stove but I did offer some suggestions on its design .

When I arrived GTZ had already begun developing prototypes for the two pot 'rocket ' Lorena mud stove as well as a single pot shielded mud stove. I made a number of recommendations: that they insulate the combustion chamber of the 2 pot stove and follow some simple rocket stove principles (shelf under fire, internal rocket elbow geometry, insulation, and proper gaps for optimal heat transfer).

2 pot Rocket Lorenas in Kampala
A number of tests of these stoves were performed by GTZ using the original WBT/PHU testing protocol (GTZ-EAP has the test data and the specific results so Im hoping that Leonard Magerwa might post the test data - Leonard are you out there?) during 2003

From my recollection the results looked something like this:

2 pot 'insulated' Rocket Lorena. Three versions were constructed and tested:
a.. -with pumice combustion chamber
b.. with 50/50 vermiculite c combustion chamber
c.. -with sawdust clay (unfired/non ceramic)

All of these stoves had very similar test results , something like slightly
above 30% PHU

2 pot mud rocket Lorena
a.. This stove performed slightly worse , something like 28% PHU

Single pot shielded fire mud stove
a.. This single pot stove had similar performance to the 'insulated' 2 pot stove. Around 30%. (sorry that's the best picture I have. Leonard , do you have a better one?)

Note: These 'lab' results are from the stove testing site that was set up in Kampala. They were built to exact specifications (stove built around 2 standardized pots and a 1 cm gap around both pots). As Dean and Tom pointed out, the stoves that were tested by USAID were most likely not constructed as per the original specifications nor were they used in the manner they were intended ( i.e. pots not submerged)

a.. The 'Insulated' versions all produced similar results in overall
efficiency even though they offer a spectrum of insulation quality : from
relatively high quality insulative materials such as pumice to a lower
quality insulative material such as unfired clay ceramic model .

a.. There was only a few percentage points of efficiency gained by
insulating the 2 pot stove

a.. Given the similarity of the results of the insulated stoves we could
conclude that in terms of fuel efficiency , the insulation of the
combustion chamber does not have a great impact on overall efficiency ie
reduction in fuel consumption. ( One would imagine that they had an improved
combustion efficiency, Unfortunately emission testing equipment was not
available during these tests but it did appear that the insulated stoves
were producing less visible smoke than the non insulated version)

a.. The un-insulated single pot chimneyless shielded fire proved to have
a similar efficiency as an insulated 2 pot chimney stove

Although these tests obviously aren't definitive they do point in a
certain direction which seem to support what Aprovecho has been saying for some time:

a.. Optimizing Heat transfer is important for reducing fuel consumption.
This means : using a skirt and/or tapering the slope underneath the pot so
that it reduces cross sectional area by .75 X

a.. Insulating the combustion chamber will have a greater impact on
improving combustion efficiency than it will on heat transfer and fuel
efficency

a.. With out standardization we can expect high performance or consistent
results

GTZ-EAP for a number of reasons - that they could elaborate upon - decided to promote the 2 pot Rocket Lorena ( my understanding is that the insulated version is promoted where possible, but due to poor access to materials,
it is the un-insulated version that is often produced in the field

When the stoves were designed it was recognized that they would face some significant dissemination challenges:

a.. Design drift. without proper tools and training the local producers
would not be able to produce the stove to the exact specifications of the
stove

a.. Material substitution. Many owners would not be able to afford the
metal chimney that was needed for optimal use of the stove. Instead local
producers often made shorter chimneys out of mud that were difficult or
impossible to clean and very slow to generate draft due to their higher
mass .

a.. User 'error' Users using different size pots and not submerging the
pot into the stove. This would obviously decrease heat transfer , increase
fuel consumption and lead to increased smoke in the kitchen ie not produce
similar tests results as those produced at the Kampala test site.

The 2 pot sunken pot Rocket stove has been a meaningful experiment ( I would like to acknowledge The staff at GTZ_EAP (Phillipe Simonis, John Kutesakwe and Leonard Magerwa ) have worked very hard to produce a large quantity of stoves in a relatively short time period ( 50,000+ in 3 years)

Way forward?

Any household stove project is going to be faced with many challenges. How do we bring fuel efficient stoves to the people who can least afford them but need them the most?. How do we bring standardized stoves , which require technical ability , accurate tools and perhaps even advanced materials to these users. Who is going to pay for them if the users cant? It seems that that CDM mechanisms and factory production are one option for delivering
stoves to the poorest.

Of course, one avenue that has not been fully explore din Africa is dissemination of the single sunken pot shielded fire mud stove. Given the results of the testing done in Kampala in 2003 , it seems that there is potential for this stove to save fuel . Of course there is still plenty of opportunity for that stove to be poorly built and used.. Although given that it doesn't require two pots for it to work , nor an expensive chimney there is the chance that it could fill a certain niche in the stove world.

I can envision multiple shielded fire stoves being constructed in and outside of the house . Each stove sized to a specific pot. Since the stoves would be very low cost , the users could build many stoves as needed.

Its is an exciting time in the household stove world. We still have not come up with a fuel efficient stove and dissemination strategy to bring stoves to poor households in Africa. Its going to take a lot of trial and error , and
fumbling around in the dark to work out how to do this.

Btu Calculator

desc=Excel sheet by Ken Smith. Water boil and Btu

A great Excel sheet pertaining to different species of wood.

Snip:

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