What is the Stirling engine efficiency formula and how does it determine the overall performance of the engine?

The efficiency of a Stirling engine is determined by the formula: Efficiency 1 - (Tc/Th), where Tc is the temperature of the cold reservoir and Th is the temperature of the hot reservoir. This formula shows how well the engine converts heat energy into mechanical work. A higher efficiency value indicates better performance, as more of the heat input is converted into useful work output.