The effect of displacer stroke on the performance of a 4K Gifford-McMahon (G-M) cryocooler has been investigated. Displacer strokes of 30mm, 25mm, 20mm and 15mm are examined. The largest cooling capacity at 4.2K and also at 7K is nearly equal for all the strokes, but the first stage cooling capacity at 50K is much improved by optimization of the stroke. The optimum stroke is 20mm from the experiment. The cycle speed at which the maximum 4.2K cooling capacity is obtained is different for each stroke, and is smaller when the stroke is longer. The reciprocal of the optimum cycle speed is in proportion to the stroke.
The input power dependence of the 4.2K cooling capacity and the COP at 4.2K has also been investigated for strokes of 30mm, 25mm and 20mm to improve the efficiency of the cryocooler. The experiment is carried out at the optimum cycle speed for each stroke. The 4.2K cooling capacity and the COP at 4.2K has basically the same input power dependence for all strokes. The largest COP at 4.2K is obtained at an input power of about 2 kW.
Development of a High Efficiency 0.5 W Class 4K GM Cryocooler
Cryocoolers 10 ; Chapter : 68 ; 575-580
2002-01-01
6 pages
Article/Chapter (Book)
Electronic Resource
English
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