Abstract
We are now planning and design a new α+ -type engine that is considered about higher buffer pressure and higher engine speed. Note that the α+ -type mechanism is suitable for low-temperature-difference Stirling engines and the α+ -type engine has a displacer consisting of two pistons that are connected via rods. Therefore, it is possible to use a regenerator with a sufficiently large area within a small range of temperature difference and to suppress the load applied to the crankshaft. The α+ -type engine is most effectively applied to power generation using solar heat or combustion heat from a wood biomass because the engine can be driven by indirect heating using 300 degC thermal oil. We report the plan and design of new 10 kW class engine that reduces volume of 1/3, increases thermal efficiency from 16% to 20%.