Disruptive cryocoolers for commercial IR imaging

Abstract

The recent advent of high operating temperature infrared detectors allowed operating them at temperatures in excess of 150K without compromising performance indices typical of their 77K predecessors. These substantially relaxed cooling constraints along with a fundamentally higher coefficient of thermodynamic performance called for the development of a next-generation of low size, weight, and power cryocoolers purposely tailored for such high operating temperature detectors. Unfortunately, the most up-to-date low size, weight, and power cryocoolers are no more than downscaled and slightly lower-priced replicas of their low temperature predecessors. They commonly rely on gaseous helium as the working agent, metal stacked-screens regenerative heat exchangers, “moving magnet” dual-piston compressors, pneumatic expanders driven by differential pistons, mechanical springs, etc. Because of the inherent limitations, the currently achieved reliability and cost indices still prevent the broad use of cooled infrared imaging in the price-conscious and highly competitive commercial segment of the infrared imaging marketplace. From the very moment of its inception in 2018, CryoTech focused on disruptive innovation, enabling drastic reduction of ownership costs by deploying alternative, cost-effective technological solutions. The list of novelties includes but is not limited to: alternative working agent, low-cost microfiber regenerative heat exchanger, “moving iron” single-piston compressor with optional tuned dynamic counterbalancer, rodless pneumatic displacer, magnet springs, etc. The authors present the outcomes of the full-scale feasibility study and prototype life testing.