Energy storage integrated solar stove: A case of solar Injera baking in Ethiopia

Many of today´s solar cookers lack energy storage and their applications have been limited to day time use while the sun is shining. In addition these cookers need longer cooking time and are less versatile to users compared with the traditional wood stoves. This article presents tests of a solar stove with and integrated heat storage designed to satisfy a particular need of some east African countries to bake their daily food (Injera). The prototype was tested in the solar laboratories at NTNU and Mekelle University, and presented for community demonstrations in Mekelle. Steam is used as heat carrier between a receiver in the focal point of a concentrating dish and a solar salt based latent heat storage. The stored heat enables users to bake at any time. The storage has a capacity to retain usable thermal energy for about one to two days depending on the amount of insulation. This system can supplement the existing electric and biomass Injera stoves and provide inexpensive and clean energy solution for food preparation. Solar baking provides benefits in terms of human health, environmental strain and high costs associated with biomass fuel.