Movement of linear compressor and displacer in a displacer pulse tube refrigerator

Till now, the efficiency of the pulse tube refrigerator with inertance tube as phase shifter is still lower than that of Stirling refrigerator. One of the reasons is that the expansion power from the pulse tube is exhausted by the irreversible loss in the inertance tube. To overcome this problem, displacer type pulse tube refrigerator whose theoretical efficiency is same as Stirling refrigerator is proposed. Its performance strongly depends on the proper movement of the pistons of linear compressor at the condition that the linear motor runs at its resonant point with rated current and displacement, and the proper movement of the displacer. An investigation with numerical simulation is implemented. The results show that the optimum weight of displacer piston has almost no relationship with the linear compressor. The current displacement ratio of the linear motor can be adjusted by the weight of the piston for a given piston diameter.