Three novel regenerator concepts that have the potential for significantly improving the coefficient-of- performance of Stirling-cycle cryocoolers at temperatures below 20 K will be designed and evaluated. The innovations consist of two types of active regenerators and a novel combination of materials that yield a high specific heat even at low temperatures. The active regenerators act as if they have an infinite specific heat. The three concepts are important to NASA's various missions. Many NASA payloads depend on cooling infra-red sensors to temperatures on the order of 2 K. Such temperatures can currently be attained only with refrigeration that uses liquid helium as the working medium. The proposed concepts can reduce significantly the cost of liquid helium in space. For example, the cost of producing liquid helium on earth would be decreased. More importantly, helium cryocoolers may become practical in space, whereas currently they are so impractical that helium must be re-supplied from earth.
Potential Commercial Applications:The results could be used by companies that supply cryocoolers and helium and in terrestrial cryogenic applications such as superconducting magnets for fusion reactors.STATUS: Phase I Only
