Development of High Efficiency/Output External Combustion Engine and Advocation of Application to Biomass Power Generation System

Today, power generation utilizing renewable energy such as biomass fuel has been attracting much attention as a solution to energy and environmental problems. In this research. we devised a new mechanism to achieve high power generation by using a Stirling engine, which is highly efficient, with steam as a working fluid We carried out a theoretical calculation of the case where steam was put into the high-temperature cylinder during the isochoric heating process of the Stirling engine. This calculation showed that the mechanism can greatly improve the output, compared with the one without steam. We also conducted the same calculation in a gamma-Stirling engine, and confirmed the improvement of the output. Furthermore, when we used biomass fuel to operate the gamma-Stirling engine with the mechanism using steam, we found that we need more than 50 kg of running water per 1 kg of wood chips in order to operate it efficiently. To obtain this amount of running water. therefore, the engine should be constructed in the areas along the coast and rivers, where its performance is expected to be developed to a practical level.