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Power Hardware Technology

Making a Better Solar Cooker 167

Posted by Soulskill
from the making-high-tech-low-tech dept.
New submitter jank1887 writes "Back in 2010, the aid organization Climate Healers gave a number of solar-powered cookstoves to rural Indian villages. The stoves were rejected by the communities, mainly because they were useless when they were wanted most: for the evening meal sometimes after the sun goes down, and for breakfast before the sun has risen. Following this, the group issued a challenge to EngineeringForChange. Details of the challenge include the need to provide 1kW of heat at about 200C for two hours in both early morning and late evening, and the users should be able to cook indoors, while sitting. A number of groups, mainly at U.S. and Indian engineering institutions, accepted the challenge, and developed potential solutions. Now, almost a year later, the ten finalist designs have been selected. The actual papers have been posted to the E4C challenge workspace. The goals of most of the designs are to keep the technology simple, although there are a few exceptions, and many include sand-, oil-, and salt-based concentrated thermal storage. Many reports include some level of discussion on the social and economic considerations, barriers to acceptance and sustainability, and how to overcome initial resistance to adoption."
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Making a Better Solar Cooker

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  • My Solution (Score:5, Funny)

    by SJHillman (1966756) on Friday February 17, 2012 @02:49PM (#39077391)

    Solar panel, a bunch of lead-acid batteries and a George Foreman grill and they're good to go.

    • Re: (Score:2, Insightful)

      by emilper (826945)

      yes, and they're ready to go and eat cake

    • Re:My Solution (Score:5, Interesting)

      by Asic Eng (193332) on Friday February 17, 2012 @03:02PM (#39077575)
      Try to build it within their cost requirements, present your prototype and compare it with the other designs. If you think you can do better, then help out - you could really make a difference to the lives of many people. I suspect you'll find that your initial idea won't be quite as good as what the other guys came up with, but generally there is always a better solution around somewhere. One more person looking for that can't hurt.
      • by Asic Eng (193332)
        To clarify why I think the other guys have better solutions: e.g. the first design doesn't need solar cells (just reflectors) and has no batteries (stores heat instead of electricity). That's a lot more low-tech thus probably better suited for the place where they use it, and likely less expensive.
        • My design's only real advantage is you could whip it together in about 10 minutes using off the shelf components. The batteries would stop charging fully within a year or two of regular use, the Foreman grill is pretty limited in how much you can cook on it and solar cells are damned expensive.

          My original jest aside, these designs are pretty cool. I wanted to build a solar oven once, but I live in central and western NY where a solar oven might be useful two or three days out of the year. Now, a wind-rain-a

        • by Ihmhi (1206036)

          To be fair to the first post, using solar panels or windmills and car batteries is very common in Africa. They're used to recharge cell phones or lightbulbs at night. If there could be an efficient and cheap electrical stove, that could probably be plugged into the existing, ad-hoc infrastructure.

    • Re:My Solution (Score:4, Interesting)

      by yog (19073) * on Friday February 17, 2012 @03:19PM (#39077783) Homepage Journal

      Some day, photovoltaic panels will be dirt cheap and will be perfect for these rural villages, but right now they're too expensive even for most Americans.

      When I was a teenager, I build a solar stove out of cardboard, plywood, and aluminum foil, based on a design in a book I read. I probably could have made it totally out of cardboard; I wasn't much of an engineer/architect :)

      Anyway, the thing worked amazingly well. I demonstrated frying a hamburger (not something you would want to show the Hindu villagers, by the way) and my family was blown away. However, it had three disadvantages. First, it was extremely bright. To stand more or less in front of it to turn the food was a blinding experience.

      Second, you needed a black-bottomed pan, which we didn't have, so I painted an aluminum pie pan black on the bottom.

      Third, like the article says, it only works in full sunlight. You don't really want to cook the meat and veggies at 3pm, you want to get them started around 5:30 or 6 in most households. It's likely that the villagers are working in the fields or small workshops all day and don't get around to supper until 7pm or later.

      At least, it should be quite possible with a reflector cooker to make large pots of rice during the day, which they probably do anyway since it takes relatively long. Solar reflector cookers are perfect for that application because rice mostly wants to simmer at a lower temperature.

      • by drinkypoo (153816)

        I have quite a bit of experience cooking with a Sun Oven (tm) and while there is something to what you say, the situation is more and less complicated than that. First, the inside of the solar cooker box is best black, and the box best insulated. You cover it with a piece of glass and the reflector is above that. The glass doesn't seal down perfectly so that lets out some steam pressure, but it still stays quite moist inside so many types of cooking don't work very well and even more require adjustment, les

  • by Firethorn (177587) on Friday February 17, 2012 @02:52PM (#39077419) Homepage Journal
    I wonder how they thought the original designs would be accepted in the first place - We've long incorporated larger tanks for solar water heating to provide hot water at night. Also, even rural types like their convenience, which means being able to cook inside. BTW, for the Americans - 200C ~ 400F. Considering 80% of my cooking is at 350F, that's sufficient. Reviewing the designs, I am a touch concerned that I don't see thermostats for keeping the temp steady. Not as necessary for meat, but if you're baking bread you need fairly fine control.
    • by Asic Eng (193332)

      It's not just the inconvenience, it looks like the original designs broke down as well. So the new designs need to be more sturdy, as well. I hope they can get this to work - helping to solve deforestation, reducing cancer risks and eliminating some very hard labor - it really would be a boon for these people.

    • by Phanatic1a (413374) on Friday February 17, 2012 @02:57PM (#39077511)

      Considering 80% of my cooking is at 350F, that's sufficient.

      It looks like a number of these designs can't even come close to that:

      For night cooking, water passes through the system, becomes steam and enters the kitchen through PVC pipes....
      At night, the cook pours water into a spout on the side of the device, the water trickles through channels surrounded by the hot oil, converts to steam and rises to heat a hotplate for cooking...
      The device stores excess heat in an insulated chamber filled with salt and can continue to heat water for steam cooking at night...

      You can't heat a hotplate to 350F with 212F steam, let alone steam that's cooled off substantially by expanding through PVC pipe to enter your kitchen. People want to cook their food, not just warm it up.

      • by royallthefourth (1564389) <royallthefourth@gmail.com> on Friday February 17, 2012 @03:03PM (#39077589)

        Steam can certainly be much hotter than 212F; that's just the minimum temperature to get your reservoir boiling.

        • I didn't say steam can't be much hotter than 212F. The described technologies don't include pressurizing or superheating the steam, so it will be at 212F.

      • by PTBarnum (233319)

        Why do you assume the steam is at 212F? That's just a minimum. If the heat sink is at 400F, they could theoretically heat the steam to 400F. I'm not convinced this is a good idea, given the safety risks if there are leaks, but it is possible.

        • Why do you assume the steam is at 212F? That's just a minimum. If the heat sink is at 400F, they could theoretically heat the steam to 400F.

          Only if the system is pressurized. You think that's feasible (or even advisable) in this situation?

          • by timeOday (582209)
            I won't claim to have a good working design for this application, but pressure cooking [motherearthnews.com] is claimed to reduce cooking time by 70% and energy use by 50%, which sounds good when cooking with solar energy in the dark!

            Perhaps you could heat up a thermal store in the day, put it into a pressure cooker and add water to efficiently carry the heat from the slug to the food. Apparently pressure cookers can be made quite cheaply [amazon.com]. Hmm, according to the customer reviews on that link pressure cooking is traditional in

      • You know its funny that we regularly cook with 300-400 degree cooking surfaces, but none of our food needs to get much over 170 to be safe to eat. Certain chemical reactions like thickeners won't activate until they reach the boiling point of water, but very little of what we eat needs to go above the temperature of steam.

        Everything in your food, pectin, collagen, etc that holds the food together begins to break down around 180 so that things get soft and mushy if left too long.

        Maybe these folks need to com

      • Why do you need to cook at 350F 200F will work just fine, meat tastes much better when you cook it at lower temperatures. Most people consider a food too hot to eat if it's temperature is above 160F so 212 is more then warm enough to cook with.
    • by krlynch (158571) on Friday February 17, 2012 @02:59PM (#39077535) Homepage

      We've been cooking bread for at least ten thousand years before thermostatic control came along, so I can understand that not being part of the design requirements.

      • This is correct.

        You can substitute mass for automatic control. As long as it heats up slowly, and cools slowly, manual temperature control is fine. On an outdoor brick/mud oven, you use a damper to control the amount of air that can get to the fire.
        • Baking bread (Score:5, Interesting)

          by Firethorn (177587) on Friday February 17, 2012 @03:16PM (#39077761) Homepage Journal

          Doh... Of course you're correct, and I'm mostly thinking of my micro-production at home. Of course, back in the day you had the village baker, the average family didn't bake their own bread. What I get for trying to be among the first to post. ;)

          I should have stated a concern more for how easy it is to control the temperature of the stove - keeping it reliable is more important than the exact temperature, and many older ovens were large enough that if you wanted hot you used the back of the fire/oven, if you wanted lower temperature you kept it nearer the front.

          As for the outdoor brick/mud oven - if it's solar powered you need something to control the damper, and if you're using stored heat you need a way to moderate the heat from extremely sunny/hot days, while still keeping it hot enough on rainy days.

          Supplimental heat from a fire, or like in the one case it's 'add water here, get steam there', so if you have some sort of steam limiter, you have temperature control.

          • by CODiNE (27417)

            Really in the 3rd world temperature is not normally used in cooking. Stoves and ovens run off propane tanks or kerosine and only have "hotter/colder" controls. Also the oven designs are so cheap and awful you can't broil nor get a consistent heat throughout. Besides that locals normally have their own tradional bread types that better match their cooking implements. Such as roti, tortillas and that spongey bread tablecloth stuff the ethiopians make.

            Really they don't cook what we do and generally are uninter

            • Indians aren't foodies? You have to be kidding, right? Food is a ritual, a social event and a way of life. An Indian village will likely have more variety than most western towns. You know McD's, Taco Bell and corn dogs aren't actually considered real food by the vast majority of the world's human population.
              • by CODiNE (27417)

                I wasn't specifically talking about Indians, but in the places I've been poor people tend to eat the same food week after week. It's true that Indian food is delicious, but they don't exactly go out of their way to learn how to make foreign dishes and try new things that aren't part of their usual diet. In other words as a Mexican friend of mine said "To you it's 'Yay tonight is Mexican night!' To me every night is 'Mexican night'".

                And yes McD's, Taco Bell and corn dogs are considered a special treat in a

            • Indian's aren't foodies? Are you kidding? A small Indian village will have more variety than your average western town. Food is a social thing, a ritual, a way of life. You know McD's, Taco Bell and corn dogs aren't actually considered real food by most of the world's human population.
    • by yog (19073) *
      Rural Indian villagers probably would prefer to bake flatbreads (nan, puri, etc.), which can be made in a pan or perhaps a clay cooker. As krlynch points out, these foods were prepared long before modern appliances came about. Making rice seems like a good application for a solar cooker, too. After bringing it to an initial boil, you want the rice to just simmer for a while, perfect for the relatively low temp solar gizmos. And they probably do want to cook rice during the day, late afternoon at best, s
      • by Andy Dodd (701)

        If you read the PDF for one of the first symptoms - it was optimized for baking roti, which sounds like a variant of frybread to me based on the description.

      • And they probably do want to cook rice during the day, late afternoon at best, since it takes so long.

        I don't know what recipe you use, but when I make it plain boiled white rice takes under 10 min, brown around 30.

  • ...and sell them at a loss. That way the villagers will attach some value to the things and actually use them.

    • That isn't what happened, but thanks for sharing your narrow perspective.
      The goal of this charity is "to heal the climate crisis though reforestation" ... total hypocrisy of course, given mine and your ecological footprint.

      Wahwhua = White affluent hippy with head up ass

      Wahwhua: Here is a crappy solar cooker we designed. Use this instead of harvesting firewood.
      Villagers: This solar cooker is completely inferior to our existing wood stoves. It's not fit for purpose.
      Wahwhua: Ok, here is our new design. You sho

      • You're actually the one missing the point here. Lung disease is one of the leading killers of children and women in the developing world and the primary cause is indoor cooking fires. This is a solution to that problem.

        The fact that people who understand that have manipulated Wahwhuas into supporting these measures is just icing on the cake.

        • by Gordonjcp (186804)

          Lung disease is one of the leading killers of children and women in the developing world and the primary cause is indoor cooking fires

          So what they really need is some sort of device, possibly resembling a long metal tube, that can duct the smoke from the cooking stove out of the house.

          Shit, I shouldn't have posted that, now I'll never be able to patent it.

          • by timeOday (582209)
            Come on now, history as already played this out. 19th century London was covered in soot and it was pretty awful.
        • To which the solution is, better wood burning stoves, with a chimney to improve draft, operating temperate and efficiency, while eliminating indoor pollutants.
          Even a flue that's not completely air-tight is a start, because the pressure is lower than ambient, and it draws air in along its length.

      • by tmosley (996283)
        I'm not sure Western carbon footprint has anything to do with deforestation. We don't get our carbon from rainforests, we get it from under the ground.

        You appear to have conflated two separate issues that both happen to fall under the umbrella of "environmentalism". Same situation is where some people don't know the difference between the hole in the ozone layer and global warming.
        • by timeOday (582209)
          If the stated goal of this charity is "to heal the climate crisis though reforestation," then yes, there is a direct link - we want them to grow forests to soak up all the carbon we're digging up and spewing into the air. (Burning firewood, by contrast, is carbon neutral if harvested at the same rate as the forest re-grows).

          But I'm sure providing better health and convenience to the recipients is part of the aim as well.

          • by Jeng (926980)

            Gee, where is it better to live?

            Where you have an environment that has not been clear cut for wood fuel for cooking, or one that has been clear cut for wood fuel for cooking such as Haiti. Take a look at a satellite map of the island of Hispaniola, the poor side has no forests, that is the type of situation this is trying to prevent.

            This is about their local environment, not the global one.

            If this was about preventing forests from being cut down to help with carbon sequestration I think they would be more

            • by timeOday (582209)

              This is about their local environment, not the global one.

              I just checked their homepage, which confirms, as I previously quoted the GP claiming, that the stated goal of this charity is "to heal the climate crisis though reforestation."

              As to what good their actions are more likely to actually achieve, I agree with you.

  • by Oswald McWeany (2428506) on Friday February 17, 2012 @03:06PM (#39077633)

    Solar powered cooker?

    Grow trees using power of the sun. Sun dries out broken sticks and kindling. Rub stick on piece of wood with bow. When you get a glow- blow on it and light kindling. Cook food over resulting fire. Roast marshmallows- drink beer; get guitar (or sitar) out- everyone starts to sing Eagles songs.

    Everyone is happy and goes to bed smelling like campfire smoke. Is there anything better?

    • Is there anything better?

      Yes. Singing anything other than The Eagles [youtube.com] would be better.

    • by Asic Eng (193332)

      Oh come on. They have a problem with deforestation. They get sick from the open fires indoors. Carrying that wood through the mountains is hard labor.

      Everyone is happy and goes to bed smelling like campfire smoke. Is there anything better?

      Yes.

      • Oh come on. They have a problem with deforestation. They get sick from the open fires indoors. Carrying that wood through the mountains is hard labor.

        Fine- go ahead and be rational about it.

      • by pla (258480)
        They have a problem with deforestation.

        Burn dried dung instead of wood.


        They get sick from the open fires indoors.

        Cook outside (or more usefully, build the stove into a wall with the chimney outside and the cook-surface inside).


        Carrying that wood through the mountains is hard labor.

        Cry me a river - See #1, or... Just move closer to the damned trees.
        • *golf clap*
        • They have a problem with deforestation.
          Burn dried dung instead of wood.

          Raising animals is even more costly in terms of plant matter you need to grow. (Admitted, they might have a suitable animal already - but don't assume they all do.)

          They get sick from the open fires indoors.

          Cook outside (or more usefully, build the stove into a wall with the chimney outside and the cook-surface inside).

          They may not have any useful outdoor space. Or there may be other reasons to stay indoors; rain is obvious, malaria and other insect-borne diseases aren't quite as obvious, but are reasonable reasons to stay indoors, among others.

          And you are assuming they have a strong-walled structure that can be modified. I wouldn't bet on that. (Cardboard

        • by drinkypoo (153816)

          Burn dried dung instead of wood.

          Your comments are unavailable to them.

    • by 1u3hr (530656)

      Grow trees using power of the sun. Sun dries out broken sticks and kindling. Rub stick on piece of wood with bow. When you get a glow- blow on it and light kindling. Cook food over resulting fire. Roast marshmallows- drink beer; get guitar (or sitar) out- everyone starts to sing Eagles songs. Everyone is happy and goes to bed smelling like campfire smoke. Is there anything better?

      That's what they're doing now. And causing deforestation in the process. It's also pretty labour intensive to walk for hours to the forest, cut and collect wood, carry it back to the village.

    • Too many people cutting down the trees day after day means....no more trees.
  • by Powercntrl (458442) on Friday February 17, 2012 @03:09PM (#39077663)

    There are actually government subsidies on kerosene in place in India specifically to prevent deforestation. The kerosene stoves are actually quite safe, efficient, clean burning and relatively inexpensive (by developed nation standards). Now before you start with the "OMG fossil fuels BAD!!!", remember that the grid-connected electric ranges that are so popular here in the USA are running on varying percentages of power derived from nasty, dirty coal - with the added bonus of generation and transmission losses. Since we're talking about a point-of-use fuel, these "third world" kerosene stoves are actually a pretty green solution. Perhaps instead of providing these people with pie-in-the-sky solar stoves that we wouldn't even use ourselves, we should offer good old kerosene stoves and maybe take a closer look at our own wastefulness.

    • Kerosene is actually expensive as the price can fluctuate (even with subsidies the black market ensures price inflation). Kerosene is also responsible for many early deaths and chronic diseases due to inhaling the poisonous fumes, not to mention the fire hazards. A viable solar cooker would not only be more sustainable, but also safer for the users.
      • The Japanese and the Amish use kerosene appliances quite heavily in their societies. A properly designed kerosene stove will burn just as clean as the LP/natural gas stoves that we seem to be entirely unafraid of, here in the US. Notice the incredibly clean, blue flame this stove [youtube.com] burns with.

        What it boils down to is, as you said, a problem of getting the subsidized fuel to the people who need it. It seems like that's the real issue here, not some engineering challenge to show off to some poor villagers ho

        • Interesting. Is there a way to store that safely in my campervan?

          I want to put some of these ideas into practice. so far I have:

          -preheat water in black bag on the roof
          -paint pressure cooker black and leave in the sun
          -put water into pressure cooker
          -use a stove with a fan to get a good clean burn on fuel... ....just not sure which fuel is best yet...

          Everythings easier in the sun of course. I wonder if the expanding effect of ice freezing could be utilised?
          In all of this I'd like to stress that water tends to

        • by drinkypoo (153816)

          I've had Japanese kerosene stoves of various price ranges and they all are fairly delicate things that need a new wick at least yearly and fuel as required. But in the sunny season, my lady and I use a Sun Oven(tm) that she's had well over a decade with no maintenance, and no emissions after production.

    • You're right, for now. In fact, you're right for the last century or two. Fossil fuels are not bad. Had fossil fuels not existed, we would have denuded the landscapes of the world of trees as surely as the Easter Islanders did. Fossil fuels, in a seeming paradox, have delayed ecological disaster.

      Unfortunately, with a population of 7 billion plus and not so much oil left with better than a 10:1 energy return ratio, I think "delayed" is the operative word here.

    • by Asic Eng (193332)

      Well that's their plan, and they have every right to go about it the way they think is best. There may be better or more efficient plans to be sure, but lets not forget that *they* are actually doing something (including learning from past mistakes) and if you are doing something you always have the risk of failure. As long as you are just speculating it's much less obvious when you are wrong.

      In this particular case: mountainous area, no roads - carrying kerosene on someone's back up the mountain is proba

  • This is just something simple, but some summers ago I made the "Fun-Panel" from the solarcooking.org plans [solarcooking.org]. I was surprised how well it worked, was actually able to fully cook some small stuff. A fun and recommended geeky project.
  • Why does the stove need to be solar?

    For the heat storage solutions, what happens when someone (a child) kicks the stove over by mistake? Burns, disfigurement, death. Great.

    Why not just a propane stove with a "turn off if you tip over" design?

    • by Daniel_Staal (609844) <DStaal@usa.net> on Friday February 17, 2012 @03:52PM (#39078217)

      Propane is expensive and hard to store and transport. (At least by 'developing country villager' standpoint.) Easiest way to transport it is large metal canisters, of which the canister itself would cost a month's salary, quite often. Of course, the canister is recyclable, so they'd only have to pay that once, but it's still an expensive item. Then they have to carry it back and forth from the refueling station, and pay for the actual fuel.

      From the villager's standpoint, that's not much different than using a wood stove; at least the wood will be cheap/free.

  • by slapout (93640) on Friday February 17, 2012 @03:39PM (#39078045)

    They need a solar powered fridge to keep the food they cooked yesterday from going bad.

    • by evilviper (135110)

      There are plenty of designs out there for evaporative food coolers which use no electricity.

  • Thanks, Slashdot (Score:5, Informative)

    by Rob Goodier (1861316) on Friday February 17, 2012 @04:18PM (#39078563)
    I wrote the article for Engineering for Change and I'm so glad to see this discussion on Slashdot. I've been a fan reading the daily email for a while now. It's interesting to see that, in a just a few comment strings, some of you came to the same conclusions about the best ways to introduce new technologies that it has taken maybe decades for people who are educated in development issues to reach. Also, your discussion of better solutions other than solar (efficient wood stoves) and better materials (why olive oil?) is the same kind of thing that the community at Engineering for Change struggles with. Our members find different answers that sometimes conflict, and often a solution depends a lot on the place where you use it. So, a universally perfect cook stove might not exist. Just a few thoughts. Thanks again! Rob
    • Some of us have been educated in development issues. ;) A site like this is worldwide, and draws a lot of people. Even if they have no formal education in the subject, a portion of the population will have seen or worked with the issues directly. It wouldn't surprise me if some of the comments are from people currently living in countries where these are targeted, who can drive by the people it is for any time they wish. For myself, I grew up in developing countries in a family who were working directly

  • Sorry. Couldn't resist after seeing the following comment here https://www.engineeringforchange.org/news/2012/02/04/ten_solar_cookers_that_work_at_night.html [engineeringforchange.org]

    Re: Ten solar cookers that work at night
    Hi I has been worked for a better new solar cooker, These schemes seems applicable,i am interested to see their details, Please send them to my email : mashhoodim2@asme.org thanks
  • We direct solar power at a large body of water, and collect the precipitation runoff in a basin (natural or otherwise). When needed, we allow the collected water to flow down through turbines to generate electricity, which we distribute and run through a resistor below the cooking surface.

  • by SmallFurryCreature (593017) on Friday February 17, 2012 @04:50PM (#39079021) Journal

    There are some real idiots on Slashdot who can't think outside the box that is their mothers basement.

    Wood burning has some nasty side effects. First off, wood isn't all that efficient for burning, meaning you need a lot of it. Neither can you turn it on/off as you want, meaning you waste a lot of energy. Consider a gas grill to a coal one. The coals needs to first burn up, then glow and finally cool down. The gas grill is hot in an instant and the moment you stop using it, you can turn of the supply of fuel.

    The second problem is that wood is not a renawable resource if you use it up to fast. Trees only grow so fast and it is VERY easy to use them up faster then they can regrow. Land is also expensive and often owned by someone. You can't just go around collecting wood from anywhere and the more people there are, the more this is true. Removing trees even if you intend to replace them also causes climate change. Don't believe this? The rain forest causes most of its own rain, trees evaporate a hell of a lot of water but also capture a lot of it again, it is a complex system that can easily turn forest to desert if upset. See the expanding Sahara as an example.

    Then there is another issue, collecting wood is a labor intensive task, often falling down to the women. Gathering it means they can't go to school, can't do anything else. It also forces them to go outside their village, in Africa especially this opens them to attack. Not every area in the world is safe to go outside. One of the reasons for putting wells inside villages is pricesly this, to protect the women and stop them to having to spent every waking hour collecting basic resources.

    The solar stove is a good idea. There is just one snag. Those making the decisions ain't the ones who would benefit from it. The mentioned problems of cooking outside sunlight hours are trivial to solve by adjusting how you eat. But the ones in charge don't want to do that, the old ways suit them just fine. They can afford to send their women out to collect wood, and if they get attacked, they are just killed to spare the family shame. Never underestimate the evilness of a village elder.

    Change will come but it will come slowly, just as it did in our own history. It isn't so long ago we cooked on wood and coal and suffered from it. Research the clean air act of Britain. You would be suprised how recent it is.

    Take it slow with this solar cooker, don't get the adults or old people involved at all, show the kids at school. Those girls will one day have to buy their own stove and if they have learned they can cook at least some percentage of their food without having to spend a fortune on fuel, some might just do it when they got the chance.

    Similar things happened in our own history, the bicycle was a huge liberator. While the proper women thought they were indecent, lots of young women took them as it allowed them to take jobs far further from home and thus increase the earning capacity of their family. If you get payed by the hour, any hour not spend travelling means more money and the further your range, the more options you have.

    These things go faster then you might think but slower then you might wish. The solution for the solar cooker is already known and used. Hot stones. Heat a stone, it retains the heat for long enough to continue cooking after the fire has gone out (sun has gone down). And people adjusted to this. Just takes time for the old to be replaced by the young.

    • by Whorhay (1319089)
      I agree with a lot of what you said, but cooking before sunrise and sunset is probably more a factor of how much time they have to spend in the field to survive than some village elder's opinion. I could be wrong though as I didn't RTFA.
  • by sirwired (27582) on Friday February 17, 2012 @04:54PM (#39079081)

    A couple of years ago, the IEEE magazine of the Society for the Social Implications of Science and Technology had a fascinating article about this very topic. (Although it did not involve solar stoves; instead it was about combination stoves/small generators to supply low levels of lighting and communication access to a rural village, in addition to a stove.) I can't remember how the electricity was generated; it was something non-mechanical... As an added bonus the stoves vastly improved the air quality of the dwelling; at least, they would have if they were used.

    What they determined was that the style of cookstove used varies by region, and that a design put together by some appliance designer many thousands of miles away is invariably not going to design a stove that is going to get used in some isolated rural village in the boondocks.

    It'd asking somebody that's used an oven all their life to start doing all their cooking over an open fire... given the choice, I'm just going to keep doing what I've been doing.

    The project also failed to account for distribution and transportation difficulties. A bulky stove weighing a couple of hundred pounds is really hard to transport into a mountain village accessibly only via a one-week journey by donkey.

  • i have to question the "wisdom" of interfering with traditional ways
    of living, like this. i remember seeing a report somewhere that
    said it was disgraceful that people in poor countries didn't have
    lights, to which the answer is, "so you want to have people not only become dependent on electricity, but you also want them to stop living in tune with nature, make them deprive themselves of sleep, and place them in front of flickering light sources?"

    in other words, they wanted to inflict the exact same kind of

  • I can't remember where I saw it, but somewhere online is a story about a village that just used a solar concentrator to heat up a huge iron block all day, and then everyone would share cooking duties on it in the evening. Apparently you could fry stuff on it for hours.

Mathematicians stand on each other's shoulders. -- Gauss

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