Refrigeration at temperatures around 80-150 K is required for infrared night-vision equipment with high resolution and fast response times. Compact, light-weight devices are necessary for many typical applications, such as for man-portable night-vision equipment, unattended aerial vehicles, and for use in microsatellites. Usually, cooling for infrared sensors is achieved with Stirling cryocoolers operating at frequencies around 60 to 80 Hz. Pulse Tube (PT) is a version of the Stirling cryocooler where the (warm) displacer has been eliminated and replaced by a pressure wave. This reduces noise and mechanical problems, and has therefore made the PT attractive for space applications, and also for various high-reliability terrestrial applications.
Increasing the operating pressure, decreasing the regenerator volume, and decreasing the hydraulic diameter of the regenerator matrix in a well-defined manner are all required in order to maintain high efficiency when increasing the operating frequency of regenerative cryocoolers. The high-frequency operation leads to higher cooling power density, and also to faster cooldowns because of the high refrigeration power density of the cold head.
- Low noise
- Light weight
Applications and Opportunities
- Cooling of Infrared and other sensors in for military applications
- Overcoming poor natural visibility conditions for airplane landing, night-vision for heavy trucks
- Atmospheric research