A Single Stage Five Valve Pulse Tube Refrigerator Reaching 32 K

Abstract

In order to enhance the performance of a single stage pulse tube refrigerator, a new G-M type pulse tube refrigerator with five valves is introduced in this paper. In this novel configuration, five valves with different flow coefficients are used to connect the compressor, regenerator, pulse tube and reservoir. The compression and expansion processes inside the pulse tube are realized by carefully controlling the opening and closing time of the five valves. The system is optimized by changing two intermediate pressures during the compression and expansion processes. A detailed description of the operating procedure and test results of a prototype five-valve pulse tube is given in the paper. Additionally, a simplified thermodynamic simulation is presented and compared with test results. Measurements of the refrigeration power and minimum temperature indicate that the performance of the new configuration is better than that of a standard two-valve double inlet configuration. A cooling capacity of 8 watts at 60 K is achieved with an input power of 1 kW, equivalent to an efficiency of 3.2% of Carnot. A minimum temperature of 32 K was reached with an operating frequency of 1.75 Hz.