FURTHER DEVELOPMENT AND OPTIMIZATION OF A THERMAL-STORAGE SOLAR COOKER

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.

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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.