The cavity heat pipe Stirling receiver for space solar dynamics

The receiver/storage unit for the low-Earth-orbiting Stirling system is discussed. The design, referred to as the cavity heat pipe (CHP), has been optimized for minimum specific mass and volume width. A specific version of this design at the 7 kWe level has been compared to the Space Station Brayton solar dynamic design. The Space Station design utilizes a eutectic mixture of LiF and CaF₂. Using the same phase change material, the CHP has been shown to have a specific mass of 40% and a volume of 5% of that of the Space Station Brayton at the same power level. Additionally, it complements the free-piston Stirling engine in that it also maintains a relatively flat specific mass down to at least 1 kWe. The technical requirements, tradeoff studies, critical issues, and critical technology experiments are discussed