Solar Stove Uses Salt to Stay Hot after Dark

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CAMBRIDGE, Massachusetts – An ingenious new solar stove could be well on its way to revolutionizing the way people cook in the developing world, where millions of people live without electricity, and toxic smoke from cooking kills more people than malaria and HIV/AIDS combined.

The inventor is Dave Wilson, a retired MIT professor and engineer who knows first hand why solar stoves have failed to gain popularity. While teaching in Nigeria, Wilson noticed that “people like to cook in the evening, sit under tree, enjoy themselves, and eat.” Deadly risk of toxic smoke inhalation aside, that sounds more enjoyable than slaving over a standard solar cooker in the blaring sun when temperatures peak.

After 20 years of experimenting in his basement, Wilson has developed an ingenious solar cooker that stores heat from solar energy collected throughout the day, which can then be used at night. The secret is lithium nitrate salt, which acts as a battery for storing heat. Solar energy is conducted through a metal plate which covers a pot full of the salt. Throughout the day the salt becomes molten hot, climbing beyond 400 degrees Fahrenheit and staying piping hot for six hours after dark. When the sun goes down, the lens is covered up, and the viscous salt works its magic as a thermal battery. Come evening when it’s time to make dinner, the only thing one needs to do is to remove the lid and start cooking.

If this solar cooker works for people in the developing world, it could mean fewer deaths from toxic cooking smoke. Providing an alternative to wood burning stoves could also slow the destruction of the world’s forests, and free up some time for young girls to go to school instead of gathering fuel for burning. Thanks to a grant from Indian charitable organization, TATA Trust, Wilson’s solar cooker is ready for its first field tests.

Jennifer Bills

Sources: FastCoExist, One
Photo: FastCoExist

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