A physical and thermodynamic model of space solar dynamic heat receivers employing solid-liquid phase change storage is developed. Generalized first and second law efficiencies are defined for cyclic operation. The solar heat receiver of NASA Glenn Research Center＇s Solar Dynamic Ground Test Demonstration System is used to generate numerical results from startup through balanced-orbit (asymptotic) conditions. In addition, a parametric study is performed to assess changes in receiver first and second law efficiencies due to changes in various system measurable parameters. Results show that parametric changes in system parameters result in maximum deviations of the asymptotic first law efficiency of less than 5 percentage points. The maximum departures of the asymptotic second law efficiency are less than 4 percentage points. Although the NASA receiver configuration is not optimized for cyclic thermodynamic performance, the cycle-integrated first and second law efficiencies compare favorably with steady-state numerical and experimental first and second law efficiencies.