“There are a lot of solar cookers out there, but surprisingly not many using latent-heat storage as an attribute to cook the food.” (barbequelovers)  The remark comes from David Wilson, a MIT professor. He has found a way to conserve the energy of the sun by using a Fresnel lens to melt down a container of Lithium Nitrate. Lithium Nitrate is a salt with a melting point 491 F or 255 C, (Wikipedia) which makes it ideal to conserve energy for solar cooking. It even promises to allow for latent-heat cooking up to twenty five hours later. I guess they need a chamber that is well isolated for this!

The boiling point of Lithium Nitrate is 873 C and this suggests that a lot of thermal energy can be stored in the system before the lithium salt begins to evaporate. Salt has typically a high potential to conserve energy at high temperature, and is used in many solar systems to conserve energy and produce energy even at night. Now this is put to practial use in a household Solar Cooker !

For the American market it is suggested to present the Wilson solar cooker with a hybrid system to allow for both propane and solar cooking. This is probably a good idea, but may be they also should consider making them all hybrid due to the fact that you might have hazy days and even rainy days also in emerging markets. Propane is also a very common source for cooking in many middle class households in developing countries. Many households have a whole range of different solutions to be able to cook their food under various conditions. When the sun is hiding, they can use electricity. When there is no electricity they use propane or an electrical generator and when there is no propane available they use charcoal or simply wood. The Wilson Solar Cooker does not seem to be the cheapest solar cooker on the market either, so a dual solution would not be a bad thing I…