Poor can't afford a proper stove with such efficiency.
A modified kerosene stove using pipes, arranged in such a way that there is no need of an additional fuel tank. It is believed that the stove has higher thermal efficiency due to preheating of kerosene (stored in the pipes) and less chances of explosion due to the distribution of pressure in large area.
Link: Low cost, high thermal efficiency, low chance of exploration
Manufacturing Capacity: b) Design Support, e) Franchising