Comparison of the dynamic characteristics and performance of beta-type Stirling engines operating with different driving mechanisms

In 1816, Robert Stirling proposed the first beta-type Stirling engine (BTSE) which have been extensively used in renewable energy. In BTSEs, the displacer and piston are coaxially arranged, resulting in a more compact design and a higher power density. In this study, the dynamic characteristics and performance of BTSEs with five driving mechanisms, namely, slider crank, rhombic drive, Ross yoke, bell crank, and Scotch yoke mechanisms, were investigated. Variations in the thermal properties of the working fluid in BTSEs were predicted using a thermodynamic model. The dynamic models of the five mechanisms were presented, and friction losses due to the piston rings, sliders, bearings, and seals were considered. The thermal properties of the working fluid and the dynamic behavior of the driving mechanisms were investigated. The instantaneous variations in the displacement of the moving components and engine speed were obtained, and the indicated power, shaft power, total friction loss, and mechanical efficiency of BTSEs with the five mechanisms were compared. The results indicated that the trajectories of the piston and displacer considerably affected the performance of BTSEs. Additionally, BTSEs with the bell crank mechanism produced the highest shaft power (1533 W) at 550 rpm, with a mechanical efficiency of 80.5%. •A complete model for analyzing beta-type Stirling engines is proposed.•The performance of the engines with different driving mechanisms is studied.•The transient behaviors and performance of the engines are simulated.•The engine with bell crank mechanism can produce the highest power 1533 W.