A work-recovery pulse tube refrigerator for natural gas liquefaction

A pulse tube refrigerator capable of work recovery operating at liquefied natural gas temperature (similar to 110 K) is developed in this paper. Base on the thermoacoustic theory, an electro-acoustic circuit model is proposed to find the optimum working state, and the axial distributions of the key thermodynamic parameters including pressure, mass flow and phase difference between them, as well as the thermoacoustic energy in the cold finger are quantitatively demonstrated using 1-D dimensional simulation (DeltaEC). The effects of the stepped displacer and the mass-spring assembly in work-recovery phase shifter on the cooling performance and efficiency of the refrigerator are analyzed. A typical prototype with the well-designed work-recovery phase shifter is experimentally investigated at 110 K to verify the simulation results, and the measured relative Carnot efficiency is more than 21%. The rapid cooling ability and the cooling performances at 90 K and 100 K are also investigated experimentally as consideration of the heat transfer temperature drop, which occurs in cooling the liquefied natural gas tank.