GM-Type Two-Stage Pulse Tube Cooler with High Efficiency
- 1.2k Downloads
A two-stage pulse tube refrigerator has been designed for maximum refrigeration powers at 20 K and 50 K, when powered by a 6.5 kW of electric compressor. The modular setup of the cold head enables easy access to all components to be modified for the optimization of the system. All gas flows at the regenerator and at both pulse tubes are controlled by solenoid valves. Additional adjustment of the flow is done by throttling valves at the pulse tubes.
Two arrangements with different sizes of the second stage have been tested. With the small size second stage, the typical cooling power achieved was 55 W at 50 K for the first stage together with 3.5 W at 20 K. This corresponds to about 5.0 % of summarized Carnot efficiency. Even higher efficiency of 5.8 % Carnot was obtained for the system with enlarged second-stage components operated with 40 W at 46 K plus 10.5 W at 20 K. No-load temperatures down to 8.5 K were achieved with lead spheres for the second-stage regenerator. Some details on the design of the test rig and on operational parameters are given.
In addition, the results are compared with numeric predictions based on a small amplitude thermoacoustic model.
KeywordsSolenoid Valve Pulse Tube Expansion Power Cold Head Pulse Tube Refrigerator
Unable to display preview. Download preview PDF.
- 1.W.W. Burt, and C.K. Chan, “New Mid-Size High Efficiency Pulse Tube Coolers,” Cryocoolers 9, Plenum Publishing Corp., New York, 1997, pp. 173–182.Google Scholar
- 2.A. Ravex, I. Charles, L. Duband and J.M. Poncet, “Pulse Tube Development at CEA/SBT,” Proc. of the IIR Conf., Sidney, Sept. 1999.Google Scholar
- 5.A. Onishi, “4K-GM Cryocoolers having little orientation dependency and small influence from magnetic field,” Cryogenic Engineering (J. Cryog. Eng. Soc. Japan, Tokyo), Vol. 34 (1999), pp. 233–235.Google Scholar
- 6.J.N. Chafe and G,F. Green:, “Performance of a Low Temperature Giffbrd McMahon Refrigerator Utilizing Neodymium Disk Regenerator,” Advances in Cryogenic Engineering, Vol. 43 (1998), pp. 1783–1790.Google Scholar
- 7.Leybold-Katalog Vakuumtechnik (1998).Google Scholar
- 8.A. Hofmann and S. Wild, “Analysis of a Two-Stage Pulse Tube Cooler by Modeling with Thermoacoustic Theory,” Cryocoolers 10, Plenum Publishing Corp., New York, 1999, pp. 369–377.Google Scholar