the clean stove design solution

Andy, Carly, Dan and Robert decided on the TLUD (top-lit updraft) stove for their final design.  it won out both in their decision matrix and in their testing.  the next trick was to implement the design on a larger scale, one that would accommodate a plancha and large pots. 

stove schematic

burn schematic

based on easy availability in developing areas, the team decided to use ceramics to build the combustion chamber and housing.  the inside of the chamber is where the fire is built, and it has holes around the bottom and top of its cylinder.  these allow fresh air to come in at the bottom, and heated air to come in at the top, where the fuel has already been gasified.  the mixture of fresh oxygen and gasified fuel (exhaust) creates a secondary burn that eliminates most of the pollutants and creates a very hot fire for cooking.  the outer chamber has large holes in the bottom to allow fresh air to feed the fire.  together, the ceramic pieces create a working TLUD.





earlier prototypes

in total, the team created five generations of prototypes.  this became necessary when the original ceramic chambers cracked due to extremely high temperatures (over 1000 degrees!), achieved too quickly.  the first generation consisted of the two paint can stoves used to test out the concepts of rocket vs. TLUD stoves.  the second prototype level was the ceramic stove which was designed for testing various configurations by plugging and opening different holes, but which broke due to heat shock.  the third generation of prototypes were ingenious tiny stoves made up of soup cans for the outer chamber and soda cans for the inner.  these helped the team determine the optimum size and location of the holes in the inner chamber.  by experimenting with five different configurations, they were able to decide the specs for their next generation, a full-sized metal version of the stove made from five gallon buckets and sheet metal.  when this proved successful, they had another clay model built, this time with different clay and additives to withstand the thermal shock.  this final product is the one they will use for more testing.

generations three and four                                                                            

the other components of the stove were determined with Guatemala and similar areas in mind.  the plancha, or griddle, used for the heating surface is readily available and very familiar to people.  the team also created their own adobe bricks with mud and straw to build an enclosure around the hot TLUD stove.  this will be very familiar to local people and will also prevent burns.  because the burning process is so efficient and clean with the TLUD, the students decided that a flue was not necessary, though it could be added at a later date.  all together, the combination makes an exciting stove project.

the final design