Clean Fan Stove Combustion Technology Development

The core objective will be to demonstrate the feasibility of creating an affordable, long-lasting clean cook stove solution that delivers at least 90% emissions reduction and 50% lower fuel usage than traditional biomass stoves. Over the period 2009-2011, BioLite developed an innovative, low cost technology that uses a thermoelectric generator in combination with a fan and a unique combustion system to dramatically reduce emissions and fuel usage relative to traditional stoves. A fraction of the energy from the fire is directed to a solid state thermoelectric generator where it is converted to electricity. This electric power is used to drive a fan which delivers a precise amount of pre-warmed air to the combustion chamber via a series of jets that promote turbulent mixing and complete combustion of the solid biomass fuel. Surplus electricity produced by the fire is made available to the user via a charging port with the capacity to charge mobile phones, battery powered lights, or other electronic devices. The stove is currently capable of producing 2 to 4 watts of electricity during operation which is sufficient to fully charge both a cell phone and an evenings worth of LED light over 3 hours of normal cooking. With this charging capability the BioLite stove is able to inexpensively and conveniently provide electricity access in the rural areas where it is most needed, promoting widespread adoption of a cleaner, more energy efficient cook stove solution that delivers immediate value to the end user in addition to long-term returns from fuel savings and improved health. Standard water boil tests of early BioLite prototypes demonstrated carbon monoxide and particulate matter emissions reductions of 91% and 94%, respectively, while lowering fuel usage by 42% relative to a three stone fire. These laboratory tests show the potential of our approach to meet the significant emissions reduction and fuel efficiency objectives outlined within the topic, yet further improvements to the combustion system are necessary to ensure these reductions can be realized in actual use where operating conditions, fuel variability, and reliability have historically posed challenges. Under this SBIR Phase 1 project, BioLite will further develop its clean cook stove technology to ensure the 90% emissions reduction and 50% lower fuel consumption can be consistently realized in conditions representing actual use. BioLite will focus on optimizing the primary and secondary air jets to promote complete combustion over a variety of fire states, covering the range of power levels that support the cooking needs of target users. Primary and secondary air jet designs will be refined to deliver the optimal amount of air to critical sections of the chamber, avoiding excess cooling in the flame region and minimizing particulate matter and carbon monoxide levels in the exhaust. BioLite will also explore the unique potential of the stoves thermoelectric system to regulate flow into the combustion chamber at low, medium, and high power states, metering the forced air supply such that the ideal amount of air is delivered to the fire under a variety of operating conditions