Determining Critical Temperature Differences of Low-Temperature-Differential Stirling Engines: Nonlinear Dynamics Approach

While the low-temperature-differential (LTD) Stirling engines are innovative engines that can operate with low temperature differentials in our daily life, the problem of determining the critical temperature differences below which the engine ceases to rotate remains unexplored. In this study, we solve this problem using a nonlinear dynamics approach. We derive the self-consistent equations that determine the critical temperature differences as homoclinic bifurcation points of a dynamical model of the LTD Stirling engines. The solutions of the self-consistent equations reveal a combination of parameters that determines the critical temperature differences. This enables us to establish the fundamental design principles for improving the performance of the LTD Stirling engines beyond empirical designs.