Pulse-Tube Refrigerator and Nitrogen Liquefier with Active Buffer System

An experimental study has been carried out to determine the effects on cooling capacity of change in valve timing, frequency, buffer volume, and valve flow coefficients (Cv values) in an active buffer pulse-tube refrigerator. A cooling capacity of 164 W at 80 K is achieved with an input power of 3.63 kW. The percent carnot is 12 %. The original straight type pulse-tube refrigerator is modified to a U-type refrigerator for liquefying nitrogen gas. A liquefying rate of 1.5 liters per hour is achieved.