Making a Better Solar Cooker

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."

Re:Interesting idea...

[Phanatic1a]

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.

Re:Interesting idea...

[royallthefourth]

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

Re:Interesting idea...

[royallthefourth]

My comment took into account superheating. This is why I called it the minimum temperature, you barely literate angry teenager.

Thanks, Slashdot

[Rob Goodier]

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