Project #5: A more efficient pot for those who cook over wood fires and related technologies
Gialunuca Skirde had designed and built the a test stand, which we will use for simultaneously testing 4 pots for boiling time. Eventually, we will use this test frame to test over wood fires.
We have not yet tested this pot design but just got it.
These hemispherical, finned pots have been measured with a heat gun to be very efficient!
We have used Computational Fluid Dynamics (OpenFOAM) to simulate a number of designs. Round-bottom parts are better than flat-bottomed pots. Heat transfer fins work.
It remains an open question if we can make a "wavy" pot or a pot like an "Erlenmeyer flask" which is better than our best pot so far.
We also have a test apparatus for testing minuature 100 ml pots 3D printed in metal (see below). Our next goal is to 3D print our best pots in metal and test them using this apparatus.
We 3D-printed a pot without heat transfer fins in the 100ml size. Using a heat gun strapped to a pipe, we were able to boil water efficiently. This is not a scientific test; it is a prelude to A-B testing. Nonetheless, one must sometimes "play" to design the next step.
IMG_1046.MOV
We attempted first to use a dryer hose, and that was a complete failure. The heat gun was so hot that it discolored the inside of the dryer hose. It is clear that a great deal of heat was lost through the hose, as the discoloration faded for about 3 feet.
By the way, this small pot (we use 100ml standard test size) boils VERY quickly when put over a natural gas burner. We are learning that the temperature of the heating gas is extremely important.
Thanks to Cledden Kwanin and Ivan Urdiales, we have a computational fluid dynaimcs (CFD) simulation based on OpenFOAM. We are approaching the ability to test hypotheses with this tool.
We have a particular design based on an initial hypothesis: The faster the flow around the pot, the more the flames and hot flue gases will be "sucked" against the pot due to the Coandă effect/Bernoulli effect. Based on this idea, we have made a "fish" shaped pot (and lid) which is streamlined, with heat transfer fins.
Our initial goal is to compare this pot to a cylindrical pot.
Team Ecopot, of Rice University, did the initial work based on ideas from Public Invention. They are:
- Christopher J Fang
- Kaitlyn Wang
- Stephanie A. Ponce
- Concepcion C Appio-Riley
- Sana A. Mohamed
- Samuel Robedee
"Revisiting the optimal shape of cooling fins: A one-dimensional analytical study using optimality conditions" by Joe Alexandersen and Ole Sigmund.
https://arxiv.org/pdf/2012.04310
This project is still active, and the team is looking for additional volunteers with varied experience. Currently, the skillsets and experience that are needed include backgrounds in:
- Heat engineering
- Machining/making/3D printing
- Solid modeling/design
Alternatively, if you are new to the technical field but have interest in:
- Performing rigorous experiments, or
- Managing practical finances.
There is also a place for you on the team. If interested in joining the Ecopot or projects like it, reach out to Inventor Coach Robert L. Read or Volunteer Coordinator Miriam Castillo. Ultimately, our mission is to further the reach of open-source medical engineering, and invent in the public, for the public. Check out our Volunteer Page to learn more.