Innovative 20-kW Delta Stirling Generator for Fission Surface Power

Stirling Innovations, LLC (SI) has introduced innovative delta Stirling machines. Delta engines and coolers are a subset of double-acting alpha free-piston Stirling machines. They are characterized by having a piston on each end of a linear alternator/motor and by optimal heat exchanger interfaces and manifolds. This leads to the potential for the highest efficiency, lightest weight and lowest cost possible for Stirling machines. Development of a 20-kW delta Stirling engine is proposed to directly address NASA needs for high efficiency and high reliability fission surface power convertors. SI uses the flexure bearings with clearance seals technology developed by Infinia and Qnergy to enable unparalleled life and reliability for Stirling machines. These are exemplified by three Infinia engines that have operated at NASA GRC for over 17 years with no maintenance or degradation and thousands of Qnergy remote power generators in the field with no issues for up to 60,000 hours. The proposed Phase I project will expand the existing 20-kW delta engine conceptual design to a fully resolved preliminary design that will be ready for final design at the beginning of Phase II. The anticipated Phase II prototype will be much closer to a pre-production engine than a typical lab prototype because it uses critical components directly from the Qnergy production line.