Experimental and Simulation Study for Two LTD Stirling Engines

The low temperature difference (LTD) Stirling engine is important for solar power application. This study focuses mainly on the influence of physical and geometrical parameters on the operating characteristics of two LTD Stirling engines. It shows that a phase shift of 90 degrees-120 degrees implies the best performance of one of them (electrical powered engine), while the optimum phase shift is about 95 degrees-105 degrees for the other (solar powered engine). In addition, the friction loss increases with increasing rotation speed for both engines. It seems that the friction loss increases with the phase shift for the electrical powered engine, while it attains maximum value at 90 degrees for the solar powered engine. Thermal efficiency first increases with the heating power and then decreases for both engines. Optimum conditions for the maximum indicated power of both Stirling engines are also indicated. Comparison between experimental results of the electrical heating engine and those obtained by simulations with several complexity levels [0-Dimension (0-D), 1-Dimension (1-D), and 2-Dimension (2-D)] has shown that the 1-D model can provide the best simulation results.