M H Khanjanpour - Member of Young Researchers Society, Shahid Bahonar University of Kerman
M Rahnama - Department of Mechanical Engineering, Shahid Bahonar University of Kerman ,Kerman ,Iran
A R Tavakolpour - Department of Mechanical and Aerospace Engineering, Shiraz University of Technology, Shiraz, Iran
M Iranmanesh - Department of Mechanical Engineering , Graduate University of Advanced Technology ,Kerman ,Iran

In this paper, a gamma-type moderate temperature differential Stirling engine was designed, developed and primarily evaluated. A thermodynamic model based on the Schmidt theory was adopted to design the engine taking into consideration a temperature difference of 450 0C. A computer program was thus written to simulate the engine performance under assumed operating conditions. Based on the mentioned temperature gradient, the sweep volume ratio of the engine was found to be 3. The engine dimensions were then adjusted so as to fulfill the computed sweep volume ratio. The bore and stroke for power piston were chosen as 38 mm and 40 mm and for the displacer they were selected as 55mm and 60 mm respectively. Finally, the engine was constructed and experimented. Although the indicated power of the engine was calculated as 10.72 W at 160 rpm it was found that the brake power was just 1.2 W at the mentioned speed which can be attributed to the frictional power wasted by the engine.

Stirling engine; Gamma-type; Thermal efficiency; Sweep volume ratio