They've been around for about five years, showing great promise for use in deforested developing nations. Also very interesting to the strawbale-house / biodeisel / solar energy type (such as myself). Rocket stoves, however, probably won't create much lift (unless used in conjunction with a paper-bag hot air balloon). via
How to build a rocket stove , following Larry Winiarski's Rocket Stove Principles. These highly efficient, easy to build cookstoves can cook a meal using a handful of twigs, so the inventor says.