[Stoves] Stove Camp Newsletter 2013/heat transfer

[Lanny Henson]

Dean,
Thanks for the report which mentioned the importance of heat transfer but mentioned no specifics.
Could you or Dr. Winiarski or Dr. Baldwin expand on this?
How are you improving heat transfer?
Lanny

>Both Rockets and TLUDs were improved by paying greater attention to heat transfer. Even though getting excellent heat transfer is well described and doesn’t have to cost more it is amazing that getting more heat into the pot is so frequently ignored. As Dr. Winiarski and Dr. Baldwin point out, optimized heat transfer is a vitally import element in a good stove.
 
  ----- Original Message ----- 
  From: Dean Still 
  To: Discussion of biomass cooking stoves 
  Sent: Friday, August 02, 2013 12:07 AM
  Subject: [Stoves] Stove Camp Newsletter 2013







             
              Aprovecho Summer Newsletter

              August 1, 2013

              Summer Stove Camp comes to a close

              Sometimes Stove Camp goes so well and summer 2013 was one of those occasions. Many folks camped out and cooked delicious meals for everyone. Large projects, like a couple of bread ovens, were made and used. Manufacturers spent long, long hours testing and improving their products. Everyone worked hard and made huge progress throughout the week, especially the two prize winners. 

              There were two challenges for the week. One was sent to us by Jordan Kowalke who is working for Total Land Care in Malawi. He is designing a TLUD that will be used to burn wood chips for which he requested the assistance of Stove Camp participants. Jordan sent a list of specifications that the winning TLUD design must reach. This prize was awarded to Mick Black and Jeffrey Santiago who tweaked Paul Anderson's Quad 3 stove until it cleanly burned the wood chips and lasted long enough to make posho, a typical meal in Malawi.

              The other prize was for any stove that met the Tier rating of 2-3-3-3-3 (Thermal Efficiency, High & Low power PM, and High and Low power CO). Many stoves met this criteria so participants were allowed to vote for their favorite. The prize was awarded to David Evitt with his Guatemalan Doña Dora stove which he toiled to improve all week.

              During camp there was a ‘shotgun’ approach of many individual tests done by many operators. For this we had three testing locations set-up. The two Laboratory Emissions Monitoring Systems (LEMS) in the lab and a new configuration we are calling “IAP-in-a-Box”, which is a test kitchen with a basic hood and collection chamber that holds the Indoor Air Pollution Meter (IAPM). This system was set up with the idea that testers can watch the live output from the meter and gauge their design’s progress without having to do a full test with the more complicated LEMS equipment. The “IAP-in-a-Box” is being documented for those who wish to test total stove emissions using the small, portable, IAP Meter. Please contact us if you are interested in getting a system.

              Last summer people did many tests on charcoal stoves and it was obvious looking at the results that although charcoal stoves emitted a lot of CO they were almost all very low for PM. This year we created a large graphic representation of all the tests on the wall and added to it everyday. The conclusion was that TLUDs generally produce lower amounts of  PM than Rocket stoves but there seemed to be two classes of TLUDS: really clean ones and only moderately clean ones. Both Rockets and TLUDs were improved by paying greater attention to heat transfer. Even though getting excellent heat transfer is well described and doesn’t have to cost more it is amazing that getting more heat into the pot is so frequently ignored. As Dr. Winiarski and Dr. Baldwin point out, optimized heat transfer is a vitally import element in a good stove.

              The progress with the TLUDs was impressive. Several of the stoves worked well with different fuels and had adequate turn down ratio. Paul Anderson helped everyone to understand TLUD mechanics and air control. He was joined by Ron Larson, Art Donnelly, and others who are evolving the TLUD approach.

              There is so much work that any motivated person could do, solving problems of the poor and moving humanity towards a more fulfilling and elegant future. Dean joked that even a monkey could follow the iterative design method and would eventually come up with innovative solutions to issues such as food drying, desalinization, solar heating, and stoves. All it takes is making a change or two per day in the prototype and seeing if it performs better or worse. That’s what we do here at Aprovecho and we hope that it catches on.

              Sincerely,

              The Aprovecho Team

             
              Photos by Simon Anderson and Sanya Detweiler. Aprovecho Research Center is a lab based in Cottage Grove, OR--visit the main website for more information. Please email sanya at aprovecho.org regarding subscription to these updates.
             
       





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