Topics Needing Research

Whether you're planning a science project or are just a solar cooking enthusiast, Solar Cooker International wants you to know that your research can help extend the world's knowledge of solar cooking and be of great help to people around the world. You should be aware that it's easy to build a high-performance solar cooker if you have access to modern materials. However, the more than a billion poor people in the world, who could really benefit from having a solar cooker, don't have access to such materials. This means that your research will be most useful if it concentrates on the simplification of cooker design or on the use of low-tech, local materials.

Here are some ideas for areas of research. We will post your findings on this page if you let us know what you found out. Findings posted in the last 30 days are marked with . We are also interested in adding new areas of research to this list. Send those too to webmaster@solarcooking.org. 

General

• What is the simplest way to make a thermometer that could show when water has reached a temperature that would kill any microbes in it and make it safe to drink? Throughout the world it is mistakenly believed that unsafe water needs to be boiled for 20 minutes to make it safe to drink. Bacteriological tests in the field have confirmed that it is only necessary to bring the water to 65° C (165° F) for 20 minutes to make it safe to drink. It is easy to see when water is boiling so no temperature measurement  in needed. However, it is not easy to see when water gets to 65° C. What is needed is a simple method that is available to poor people around the world to indicate when this temperature has been reached.
  
  Solar Cookers International has designed the WAPI for this purpose.
  It might be possible to use beeswax to indicate this temperature
  Matthew Collier has adapted an idea by Galileo here.
  A document explaining various methods to make thermometers from simple materials is here.
  
  Philip Guest has this suggestion: Woods metal is an alloy of Bi (50%), Pd (25%), Sn (12.5%), and Cd ( 12,5%). This has a melting point of 346 Kelvin, (70C). Sounds complex, but a lot of modern golf club drivers contain the alloy for it's mass, encapsulated in a strong sealed vile it should be safe, e.g. Pyrex. Recycle those clubs, find an ethical manufacturer, and were away, costs should be small, and can be started in most developed countries. Logistic problems, storage and distribution but this could be coordinated. A test tube and a bung could suffice. 

  Philip Guest had another suggestion: Methanol boils at 65°C. One could design a vial that is dynamically unstable so that it would fall over if the methanol in it goes above its boiling point.

  Can you think of a simpler design?
   

• Does placing contaminated water into clear plastic bottles and exposing the water to the sun (not inside a solar cooker) actually make it safe to drink? There is a technology called SODIS being promoted around the world for this purpose. There is some doubt about whether this really makes the water safe to drink. A good science project would be to test this by using toilet water and measuring using the Colilert System.
   
• How could you use solar energy to melt together shredded plastic bottles to make a waterproof roof tile?

Box Cookers

• How does a sheet of plastic film (like an oven cooking bag) compare with a sheet of glass for the glazing? Does a double sheet of plastic film equal a single sheet of glass? Do windy conditions effect plastic film more than glass?
  
  Here are the findings of Ajit Kumar N Shukla
   
• How does cooking in a clear jar compare with cooking in a jar that has been painted black?
  
  Michael Michalowicz found that painting the jar black increased efficiency by 6%
   
• How can you make a dark paint that poor people around the world can make using simple materials (ash, egg white, sap, wheat paste, etc.).
  
  Shannon Cox suggests blackening the outside of the pots over a fire. She has aluminum army mess kits and they turned black the first time she used them cooking over a fire. We are aware that this can work. It would be nice to know how long this takes and if there are ways of quickening the process.
  

  Håkon Kjernli writes, "As a kid, I read an advice for blackening metal: dip it in linen seed oil and hold it into a fire. The oil burns and leaves a solid black color, similar to what you get on an old open-fire cooking pan. I guess any kind of oil or fat will do the job. Do this a few times and as I recall, you should have a very durable black coating which does not insulate or crack. I have not tried it for 30 years, but I will the next time I sit by a fire with a piece of metal and some fat or oil nearby."

  
   
• How could a simple mechanism be designed that would automatically turn the cooker after a few hours? With a box cooker, it is only necessary to turn the cooker once if you're cooking a difficult food like beans. Figuring out a simple way to make this one turn happen automatically is what we're looking for.
  
  Jim Thomasson came up with this method: Solar Tracking With A Box-Style Cooker
  
  A plan for a Solar Water Clock Drive was submitted by ChrisM1111@aol.com
  Jeff Monaco proposes using a magnifying glass to burn a twig to release a weight when the sun has moved sufficiently
  Tom Sponheim suggested using wax melting instead to remove the need for a magnifying glass
  
    QT Sunshine came up with this design
  
• Should the walls inside the cooker be foiled to reflect the light, or should they be painted black?
  
  Ethan discovered in his science project that an empty oven with shiny walls and a steel plate on the bottom got 8% hotter than the others he tried.
  
  The cooker without foil shown in this picture was able to pasteurize water.
   
• How can you waterproof cardboard (beeswax, oil, etc.)?
  
  One participant found that using gelatin worked very well to water-proof cardboard.

Panel Cookers

• How can plastic bags be made to last longer? Should they be held away from the hot pot using some sort of frame?
  
  Wietske Jongbloed devised a wire frame to do this.
  
  Ashok Kundapur came up with this design.
   
• Does it help to raise the pot off the ground? If so, what should you use to lift it? Should the lifters be place inside the plastic bag or outside?
  
  Dr. Steven Jones found that raising the pot on a wire frame improved cooking greatly.
   
• How much does a double bag improve cooking?
   
• How should you arrange it so multiple pots could be used (stacking, side-by-side, etc.)?
  
  Ravindra Pardeshi sent the results of his testing and it is posted here.
   
• What materials could be used to build the cooker besides cardboard? Papier-mâché?
   
• Could you use one plastic bag around the base of the pot and another smaller one over the lid, thus allowing the pot to opened during cooking without opening the bag?
   
• Does the bag have to go all the way around the pot, or could it fitted with a frame to keep it open and just be lowered over the pot like a dome?