Heat-dynamics network model and energy analysis of a miniature free piston Stirling cryocooler for application of high operating temperature infrared detector

High Operating Temperature (HOT) infrared detectors with a miniature Stirling cryocooler, operating at 150 K and above, will become smaller size and more popular in applications with the development of infrared detector technology. In this paper a miniature free-piston Stirling cryocooler (FPSC) is developed for the application of HOT infrared detectors. Allowing for the active properties of the regenerator, actual thermal process in each chamber of the Stirling cryocooler, and the heat-dynamic coupling, the two-port network model is derived for each component of the FPSC, and then a heat-dynamics network analysis model is established for the entire cryocooler. Meanwhile, the performance prediction with the experimental verification is performed for the cryocooler prototype developed. Then analyses of energy losses are carried out, and the studied results shows that main loss for the expander of miniature cryocooler is ascribed to the non-ideal heat transfer of the regenerator. For the miniature cryocooler prototype developed, the cooling capacity of 1.35 W@150 K is achieved, at room temperature of 23 °C and the input power of 10 W_AC. The relative Carnot efficiency of the prototype is 13.5 %, and the maximum input power is 20 W_AC and the weigh is 200 g. The achieved performance is quite appropriate for the application of high operating temperature infrared detectors.