A biomass powered Ringbom-Stirling engine for developing countries: a low-budget solution for distributed electricity generation

In many isolated settings electricity is not available or is supplied by fossil fuels, while biomass is used for cooking purposes, not exploiting all of its potential. We are building a prototype of a biomass powered 1kWel Ringbom-Stirling engine that doesn't require high technology, but nevertheless brings relevant innovations. This solution aims to generate electricity using the same source used for cooking. It is meant to be used and to be producible in developing countries, where distributed electricity generation, using locally available primary sources, can help reducing the dependence from foreign aids or suppliers. The system we are building is composed of a down-draft gasifier which supplies the syngas that is then burned to heat the Ringbom-Stirling engine, which produces electricity, while the remaining heat is available for cooking. We discuss here the general scheme of this solution with particular regard for some new applications that greatly simplify the operation of traditional Stirling engines, such as metal bellows, used instead of the typical cylinder-piston arrangement, to totally eliminate the friction due to sealing needs between moving parts.