A Solar Cooker Prototype for a Greener Tomorrow


Principal investigator:  David Gordon Wilson
Professor of Mechanical Engineering, MIT - emeritus

This note is written because someone unknown has publicized an old highly fanciful and almost wholly inaccurate but beautifully illustrated account (by a small group of business students at MIT) of our solar-cooker work, calling it a "grill", and showing it apparently being used (in highly creative illustrations) by tropical people using devices that have no relation to what we are trying to do. I am having to write to many good people who have reacted with delight at the outrageous claims of performance of this device. The following paragraph is taken from a recent proposal for further work on the real cooker. I am happy and grateful to report that the Tata Foundation has promised 24 months of support for a graduate student to develop the cooker to become a fully working and useful unit.


The solar cooker is one that stores solar heat in a sealed container of melting salt for about six hours during a tropical day. At a chosen point, such as when all the salt is melted, the cooker (basically a hot-plate hermetically sealed on a stainless-steel pot containing the salt) is automatically fully insulated and can be used for cooking in the evening, three-to-five hours later.  A somewhat crude version of the cooker has shown that the concept is fully feasible, using a solid copper finned hot plate as the interface between the thermal storage and the heating surface. Copper is probably too expensive, and cast-iron has been used in a second version, to lower the cost, but is very heavy. Coated aluminum alloys and other alternatives need to be examined. The absorptivity and emissivity of the solar-receiving area need to be analyzed, tested experimentally, and optimized. The size appropriate to a family or village group must be defined.  A timing system, presumably using clockwork, to keep the cooker aligned with the sun’s position during the six hours of insolation needs to be fully developed. The goal of the proposed program is a series of tests of the cooker in tropical-village conditions and the incorporation of the improvements found to be necessary and desirable.



  1. This is BS. There is no way you can provide a grill area as large as the fresnel lens with heat for three times as long as it collected the heat, and give it at 450 degrees. You would be taking an area of a few hundred square inches, exposing it to sun for five good hours and maybe ten usable hours a day, then heating a grill area of about the same size at a higher temp for longer.

    Maybe the laws of thermodynamics went out of style.

  2. Bravo,

    We will have to see how the students at MIT make out with their research. As I think about it, the real test will be how efficiently they are able to store the energy and then convert it back into heat without waste.

    If they are successful, the world will benefit. If they are not successful, hopefully they will document their findings so as a society we can learn from their research...

    Just my thoughts...

  3. @Bravo Sierra:

    The Wright Brothers called and left you a voicemail-
    "There's no way that the laws of physics could EVER allow for human flight. Don't bother trying. Just give up now.......oh......uh.......wait a second......"

    And then they mysteriously hung up. Curious.

  4. Well, I would love if such a product would be possible, but it does annoy me that the photos are all faked...especially the ones photoshopped into an African village scene. It does make me dubious about the entire claim.

  5. What do you do if it rains?

  6. Using artifical images to promote a product is not always the best policy. In the top image, in the village, the lighting on the barbecue cormes from back and right of the scene, while on everything else it comes from left and front. On the second image, two african women with two cookers, both cookers seem to hover above ground, and both have the same reflections, of objects which aren't there.

    I'm not commenting the bottom, western image, but it seems that the cooker is inside the wall, if you follow the bottom circumference.

    I'm not saying it doesn't work - do I know? But is the price tag african, say, under $20, or western?

    On a personal note, I can't have a warm shower or cook solar today. Completely overcast. My enthusiasm wont move the clouds.

  7. Hi Josualdo and NoHalo,

    It is obvious the pictures are photoshop'd. When MIT contacted me to ask if I would provide the information on the website, I happily agreed to help. I support everyone who tries to make a difference in others lives.

    As it says in the article, the team is part of an innovation team that is trying to make a difference in the world. As part of the project I am sure they had to write a report on the possible applications of their device after it was completed.

    This was in concept phase earlier this year. Let's see if they can get it to work and change some lives...

  8. george milton says:

    If it rains I guess you eat raisin bran. Natural gas is the largest untapped (or barely tapped) resource in the world. The USA has enough natural gas reserves to power stoves for 200 years and that's just reserves we know about. There is plenty of time to do these things and research needs to be focused on getting us off the crude oil habit first.

  9. this is the biggest fake ive ever seen, i have to do a brochure in school about this thing because my teacther thinks that it is real haha

  10. Mark,

    Thank heavens for school assignments as it might help you to learn something.

    If you would actually read the article, you would find that this is a case study for a class at MIT. It is a prototype. It has not yet been implemented yet. There are no tribes in Africa using these solar grills because they don't exist yet. Of course the pictures are photoshopped, they are to indicate what might happen if they are successful in creating the grill.

    Maybe someday the grills will be a reality, but for right now, this is a case study.

  11. I tend to agree with Bravo - there is no way this thing can cook for 25 hours straight after warming in the sun for a day.

    However, it is possible that the grill will only STORE the heat for 25 hours and then cook something at 450 for 30 minutes or so using the stored heat. If the heat storage is efficient enough, I suppose this could be possible.

    Either way - put me on the waiting list for one of these if it doesn't break my budget.

  12. It will definitely be interesting to see what they come up with.

    I am with you Eldon - put me down for one as well, but it has to be priced right!

  13. this is great!!!! the students who is making the study on this grill should be commended for their desire to help the communityu. i hope this grill would work! anyways i have some questions though
    1. how soon can the Lihium nitrate be consumed?
    2. How much will the fuel cost?
    3. How safe is the fuel handling?

    i think lithium nitrates are used in the manufacture of pyrotechnics. anyways, if the students need to do more tests with this cooker. sign me in!!!!

  14. Great questions! I will forward along to the students at MIT. Hopefully they will give us an update on where they are at and get us some answers.


  15. Some facts of Lihium nitrate:
    inhalation: systemic poisoning can occur.
    ingestion: Causes irritation. May cause nausea, vomiting and diarrhea.
    derm: Causes irritation.
    eyes: Causes irritation, redness, and pain.

    in other words, toxic waste!

  16. Bravo Siera ,

    You are reacting to a strawman argument you created based on your misunderstanding of what the article actually stated.

    I can assure you that Prof Wilson and his team of MIT students are not challenging the laws of thermodynamics.

    The idea is sound and based on physics. Read the article again and more carefully without making your own assumptions as to what this device is supposed to do.

  17. Has everyone also missed the fact that lithium Nitrate is a hazardous material and highly toxic? What about disposal, production and transportation of their main material for this concept??? It's great to get people thinking outside of the box, but I would also be nice if the box was at least recyclable.........

  18. Veronika Bernstein says:

    I am researching a fresnel based cooker for my Cape Cod backyard now. I am planning to get the lens from a discarded rear projection TV. Any opinions?

  19. its a lveary good product iam intrested in buying it so send me deatail

  20. enele boitshepo says:

    Keen in purchasing the solar grills please forward the buying conditions.thank you

  21. James Robinson says:

    Doesn't look to me that this thing would work at all. There appears to be no means to adjust the elevation of the fresnel lens to track the sun. Azimuth tracking can be achieved by rotating the whole cooker or top I suppose. The solar collection area looks to be on the order of about 0.7M^2 translating into only about 700 watts of power at the two brief times of day the lens would be properly aligned - hardly enough power collection to 'fire' a grill that size even if collected over a great length of time.

  22. It will be interesting to see what the folks at MIT come up with. It is an ambitious project for sure...

  23. Marian Clinton says:

    I quote,
    Whatever you can do or dream you can, begin it, Boldness has genius, power and magic in it. Begin it now.
    by Goethe. I say good luck, and do not give up.

  24. Super...
    A quand la commercialisation??
    je serai intéressé pour la commercialisation...
    Contactez moi, j'aimerai avoir plus d'informations


  25. smith oog says:

    Dear sir/madam
    It is anice product. Maey I get the price and other feature please.
    I want to be dealer in Asia.

  26. I haven't heard how things are progressing at MIT and if this is even a commercially available process yet. There has been a lot of interest in this project, hopefully the folks at MIT are making good progress...

  27. Solarcooking mom says:

    The article never says it would cook for 25 hours straight ! What it says is that it can store the heat for up to that long so that you can cook lets say at dusk from energy you stored at noon or in the morning, which is a great idea. It does not say for how long you can have high heat in the cooking area, probably for a few hours.

  28. Terry K. says:

    How about a gyroscope type mechanism that an average person could adjust by hand to follow the sun? And each movement can be tightened or loosened sort of like adjusting a camera tripod...

  29. Really a western approach in looking for that amount of energy. if these folks have been in Nigeria they shd know that these communities wud be more than happy to cook food and boil water for three four hours at very low cost and safe. two completely different target users, marketing shd be relooked into. i personally wd be very interested to see what we can derive from the technology for the developing countries

  30. Good on MIT for being innovative and adventurous. Regarding the fuel cell, I would caution the students to consider what else might be done, destructively, with the fuel. Providing villages with solar cooking may be good socially, providing insurgents/rebels/whomever with a weapon is definitely not good socially. Hopefully in this project, the students will also be comparing passive solar cooking to their new concepts. If it's possible to provide 1000 passive solar cookers for the same cost as 1 of these new ones, how much of a disadvantage is it for the end users to cook during sunlight hours only?

  31. mike armstrong says:

    How come if one uses an image showing non-african people (which I am assuming is the ethnic origin of the people shown in some of these photos) one is careful about copyright?

    Have you gone through the same process with the people shown in these images?

  32. signalfire says:

    I agree with what Michel said. I'll be impressed when you produce an extremely cheap nontoxic unit for village use by the poverty stricken, not when you produce something a bunch of rich suburbanites will use as a status symbol while they sip margaritas. How about using ROCKS as heat storage units?

    Actually, that's it. A simple fresnel lens, a holder for it that can be tilted to follow the sun, a holder for the grills, and rocks underneath to store the heat. Good?

  33. @Mike Armstrong - I would assume that MIT, a leading academic institution, would be careful about copyright for all ethnicities used in their iTeam outputs. However, if you want to pursue questions about copyrights, I urge you to contact MIT and speak to the students that were part of the iTeam that created the case study or Derek Ham, the author of the post

  34. disgusting reporting, its not even a built prototype just a theory, yet there are photo shopped pictures of a "real " product giving people false hope , disgraceful

  35. Like all good ideas the price would be high anything to help save life or the planet seems to cost more than its worth and the gas companies will buy it out before we can get it Greed bye them makes many great ideas vanish.

  36. Pam Moynihan says:

    I love the concept and love to grill AND live in Texas with plenty of sunshine and heat. Put me on the waiting list - it would be awesome if it came to fruition!!

  37. CreoleGenius says:

    Professor would love to absorb NGO grants and development funds for production based upon his patent. Meanwhile, highly efficient rocket stoves, wood gasifier and solar ovens are already out there to be promoted and produced for benefit of everyone.

  38. I really think the way people are picking these pictures apart they have way to much time on their hands, get a life. I would think since they aren't a company they have little to nothing to fund promotion of this idea so I'm sure they just couldn't go to Africa to get a pic of some women cooking on it. I think was done to show what is possible not what is presently in use. I for one certainly hope this idea pans out and will be first in line for one.

  39. Thank heavens the one unlimited natural resource we have is student enthusiasm. Without it the world would be a sad place indeed. Thanks to all lecturers who allow students to experiment and change the way we think about things. Good luck guys, we need you to keep trying until you succeed, because when you do, it will be big!

  40. Kudos to the MIT students - will be watching to see what develops. As you those who badmouthed either the concept or the images - these are NOT marketing anything yet. They are just reporting on what they are working on.

  41. John Wendel says:

    Nothing new here, I saw a solar cooker in the 1970's that used a large parabolic mirror to melt lead in an insulated container. The stored heat was enough to run a stove "burner". The mirror was MUCH LARGER than the lens depicted here. I suspect a working version will need a much larger lens array. Of course, this in no way invalidates the concept.

  42. susan sheldon says:

    Sounds and looks wonderful. But will cost an arm and a leg as is the case with all "green" products. We claim to want to clean things up and protect the planet, yet the things that will do that are priced so far out of everyones budget but the rich. So we keep doing the same old things because we can afford them.

  43. We would love to b a part of ur study!.. we bbq evrynite!n cali w got sun so its never a unsolarday.. consider pleez..love the I idea ...eco friendy.. and I'm sure taste YUMMY!..:-)

  44. Bonjour i would like more information on the Wilson solar grill price...weight....

  45. Hi Marc,

    This isn't in production yet. It is still in early research phase and is not yet available...


  46. Marco Varela says:

    I wish the study concludes that this invention can work, if it does, please let me know so I may contact you directly.


  47. Why are we sending prototypes over sea's. Why cann't an American like me test the prototype. America first!

  48. Brian Scott says:

    Suggest the students consider submitting It as a kIckstarter.com project

  49. All you people complaining about the photo-shopped photos, companies and municipalities presenting a proposed concept like a new housing development or restoration of a brown-field present visualizations all the time. At most, it might have been a mistake to use photos of real people rather than drawings but maybe the writer wanted to make the concept more real for readers. Focus less on the images, other than that of the solar cooker prototype itself, which has NOT even been built yet, people, and more on the word description. As for the troll promoting nat-gas, ignore him/her. Fracking is creating a toxic environmental nightmare when we should be focusing more on solar solutions, and yes without the use of minerals produced via toxic methods. However, those complaining about the use of lithium, I presume you don't use cell phones, i-pads, anything wireless. What do you think powers those objects.
    Larry, focus. They're not sending the prototype overseas. It's just a freakin' photo-shopped photo. So many people commenting who are not able to focus and actually understand the words of the article. The focus of the course is entrepreneurship combining science and tech communication. At least the author has learned from the comments how many people out there in the general public can't read.

  50. Susie Solicer says:

    I think this is a fantastic idea.....I have a solar oven and it works very well...I also have rocket stove which was developed for the same reason...You can cook on it burning a very small amount of , twigs, grass, etc....Nothing wrong with being prepared to do without electric power. This grill would be great anywhere any time...Lot's of people living off the grid.....I hope it's a success.....I'll be one of the first in line. .

  51. There's lots of Solar Cookers out there already but certainly not of this sophistication..should this model pass muster & get off the ground, it would have the potential to be a huge seller (if the price is right & passes environmental concerns)..with electricity cost just gone up in Australia by 30%. I'd very happily put 1 out in the garden & use it every day..AUSTRALIA..the land of Sunshine, Melanomas,Koalas & Kangaroos..

  52. I would love to test and evaluate one of these, with he costs of fuel going up every day this grill should be a hit as long as its performance is at least equal to that of its fueled ancestors

  53. you better get these into production fast, before someone else does. just looking at it I know how to build it.

  54. Sue and Ken says:

    This is a perfect addition to a home that is off the grid. How will it perform in sub-freezing temperatures? That would be important to us here above Latitude 45. Even so, using the solar grill for nine months would be a great addition to reducing the stress on our non-renewable fuels.

  55. What about combing solar with wood chips. I like the taste of wood smoke over propane flame and it would keep it sustainable.

  56. Beautiful design for a really practical concept. If priced right this would be a HUGE hit in Nicaragua where a lt of cooking happens with wood also. Send me a test model guys!!!

  57. The heck with the US and their regulatory BS. Get these into production in developing countries at affordable prices where they can do some real good improving peoples lives, health and nutrition.

  58. Due to regs at my condo association I still could not have the "hybrid" propane and solar. Now electric and solar would be fine... Need options people. I would just prefer solar only. Hmm maybe I'll build my own.

  59. Derek Ham's beautiful visual creations have given people the impression that the "solar grill" is about to be produced. It is not! And it is not a grill but a cooker, one on which meals can be produced in the evening on a hot plate, three-to-six hours after the sun has gone down (NOT 25 hours!) After many years of making unsuccessful proposals to foundations and to the US Agency for International Development I am working on this at home using my retirement funds. And in my 85th year I am not as speedy as I once was. I hope to get a demonstrator (the third generation of the stored-heat solar cooker) working in a few months. I hope that it will then attract enough funding so that we can put ten prototypes for test in various countries, and, after incorporating all suggested improvements, to distribute one thousand. After that it should be ready for mass production at an affordable price, where possible in the countries where they are to be used. Dave Wilson

  60. I'm excited about the model for Africa, but disappointed that the model for US markets included propane. Why bother with solar if you have to have propane with it? The whole idea of solar is to get away from non-renewable fuels. Failure.

  61. Does the sun shine everyday, without cloud cover, in all parts of the United States 364(5) days of the year, Judith?


  62. What a smoke at the African models. Yes these are photo-shopped images of course.

  63. Catherine Lethcoe says:

    I want one...it is the answer for us all...

  64. Tetsuo Shimura says:

    I hope soon you have this product able to export. As you know the north and norteast region of Brazil are granted with shining days all long the year but also, are the region where peoples suffers with no facilities for a normal life such as electric energy, drink water and propan gas cookers. Other idea is to licensing to a local manufacturer in Brazil which should import from the USA the lens and lithiun nitrate. By the way, how long is the life time of the lithiun nitrate?


  66. Guillermo says:

    I would love to buy one of these, either in chrome or the black. I'm sure these things would sell, just depends on how good they cook food.

  67. Frank Kecskes says:

    Curious as to the the lifespan of the Acrylic Fresnel lense when exposed to years of degradation from the sun's UV. What would the replacement cost be of the acrylic lense itself?

  68. Nora Ramirez says:

    When will you have a prototype???

  69. Looking at the snazzy design from another keen solar cookers eyes I love it.I have never used the frenell lens to cook with yet but I know its true power and I would say get a daytime model up and running real soon as many people Im sure wouldnt care right now.
    . You can work on the extended cooking time project into the evenings on your next model that will be financed by the earnings of your first model wich Im sure you could sell millions .If I was filthy rich I would finance your project but Im not but would love to have a licence to sell them but you have nothing yet .Im going to google up for a frenell lens right now good work guys good luck and oh hurry up.You surely will have stimulated the thoughts of many inventors designers like myself.

  70. Havel J Nieman says:

    How much are the solar grills

  71. Sue Hamilton-Flory says:

    I would love to take some of these to Haiti where they have cut down almost all the trees already. They need it badly. Will there be an inexpensive model?

  72. Stupid! They have a fire burning in the background in a pit. Whose idea was that?

  73. CindraLu says:

    Wow! What a great idea. I would love to have one of those. Those would be perfect for out here in the desert. I can see these as being popular in tech countries as we try to use less wood, fuel, charcoal; and being extremely helpful in less developed countries.

  74. Peter Krutiak says:


    Can who ever posted this article please contact me by e-mail. I would like to find out who is doing the prototyping and how far along it is.



  75. great invention but unfortunately the photo of them in africa looks photoshopped?? they look like they are floating with bizzare shadows, nice idea but truly give them to those in need not just fool us into thinking you already have...

  76. M J C Rajesh says:

    Hi I would like to market this product in India is it up for sale yet? this will be a grate blessing for India.
    kindly get in touch with me.
    Regards Rajesh

  77. Hi there to every one, the contents present at this web page
    are actually remarkable for people experience, well, keep up
    the nice work fellows.

  78. Pedro Gracoeiro says:

    Need direct contact for dit or manufacturer, for the African Market.



  79. I would like to get one of those grills as soon as they hit the market, are they available yet? I am thinking of building I house as self efficent as possible and a solar grill would be a great asset to it..

  80. Dan Haywood says:

    This is an awesome invention! Way to go Mr. Wilson! Good luck to you and please keep up the good work Sir!

  81. Crystal says:

    Can it be purchased? My in-laws in Mexico would love this, is it available for purchase...the one that is pictured in Africa.

  82. Crystal says:

    Reading is fundamental.....Mr. Wilson, I did read your comments and I understand. I also understand the redtape....this will certainly change the game....so I understand the hurdles. What about selling the plans directly foreign countries so that they can produce and test themselves?

  83. Crystal says:

    Mr. Wilson...I would volunteer my time to assist you...this product really needs to get out to the world.

  84. I would be seriously interested in becoming a dealer for sales in my region of Northern California / Southern Oregon. Contact me ASAP when you figure this thing out. Thank You !

  85. Want one & I mean it....

  86. David Hendrix says:
  87. I would love to try one of these units!
    I live in N.W.Ont. Canada & wonder if these would get enough sun, through a south window, during the winter months?

  88. Carol @ Solar Cooks and Carpenters says:

    I would love to do a test drive of one of these for southern Africa. We are currently training Grandmothers to use a box cooker, that works well enough, but this one........mmmmm.
    I volunteer.
    Thanks a bunch,

  89. Keep up the good work will enjoy having one of the Wilson solar grill one day soon I hope.

  90. maria young says:

    Where can I buy one

  91. Please let me know when you get to "Kickstarter" or similar stage.

  92. Brian Kohler says:

    If anybody is really interested in building one, they can be made for a very small amount of money. Go to craigslist and get a free rear projection TV and a free gas grill. Take the Fresnel lens out of the TV, and use some superstrut to mount the lens to the grill. I used the lens to heat up a cast iron griddle and then cooked on the griddle. Even in Pittsburgh, I was able to cook chicken. This summer, I plan on experimenting with heating up the lava rocks ahead of time to see if it will speed up the cooking.

  93. William Llewellyn says:

    Water in a container, heated by the sun, evaporates. The loss of water means the container is lighter by the minute. A spring, attached to the container, exerts it's strength more and more as the container becomes lighter, to the effect that the lens is rotated to stay full face to the sun.
    Water minus evaporation, torque turns the lens. Need to work out amount of water and size of container. Imagine container wide mouthed, possibly quite flat.
    Just an idea .

  94. This is an amazing barbeque. how much sunlight do you need for this to work? can you use it during the day? How long does it store the energy for?