Step piston pulse tube refrigerator

• A step piston is used to recover the expansion work of the pulse tube.
• The step piston and the inertance tube should be optimized.
• It is more effective at higher refrigeration temperature.

In this paper, a numerical simulation is done for a step piston pulse tube refrigerator. The step piston pulse tube refrigerator is a modification of an inertance tube pulse tube refrigerator, which has a step piston compressor. The step piston in a step cylinder forms a compression space which is connected to the after cooler and an expansion space which is connected to the buffer. Numerical simulation shows that it is more effective at higher refrigeration temperature. It also shows there is an optimum swept volume ratio of the expansion space over the compression space, and an optimum diameter and length of the inertance tube for a given refrigerator.