Experimental Study on a Hundred-Watt Highly-Efficient Displacer-Type Pulse Tube Cryocooler

Displacer-type pulse-tube cryocoolers use a displacer for phase adjustment and recovery of acoustic power, leading to high refrigeration efficiency. Despite their potential, there is limited research on highly efficient displacer-type pulse-tube cryocoolers with large cooling capacities near -100 ℃. This paper presents the design of a 100-watt displacer-type pulse-tube cryocooler for low-temperature freezers and evaluates its performance, focusing on displacement motion and compressor efficiency. A validated numerical model was employed to analyze the coupling between the pulse tube and compressor and the internal phase relationship of the cold finger. Results show that under operating conditions of a 3.0 MPa charging pressure, 64.9 Hz frequency, 20 ℃ cooling water temperature, and 500 W input power, the cryocooler achieved a cooling capacity of 160.3 W at -100 ℃ with a relative Carnot efficiency of 22.2%. The displacer led the compressor piston by 59°, the internal phase distribution of the pulse tube was optimal, and the compressor exhibited a high efficiency of 78%. This cryocooler is the most efficient displacer-type pulse-tube cryocooler in its temperature range.