Wonderbag
Wonderbag is a stand-alone, non-electric insulated bag designed to reduce the amount of fuel required in the cooking of food in developing countries. Instead of being placed on a stove for the duration of the cooking period, food is instead heated to a hot enough temperature then transferred to the Wonderbag, which uses the principle of thermal insulation to continue cooking, and keeps food warm without needing additional fire or heat. Working on the principle of thermal cooking, the Wonderbag is estimated to save up to 30% of the total fuel costs associated with cooking with Kerosene ("paraffin") alone. In developing countries there are numerous advantages for the product, as it immediately helps ease deforestation of natural reserves, and it frees up those who would spend their time gathering the extra wood for fire fuel.
Read article on Wikipedia