Future military communication systems will rely on advanced superconductor digital electronics. These electronics will require efficient cooling at low temperatures near 4 K. Pulse-tube cryocoolers are a candidate cooling technology for this application. We propose to improve the efficiency of the pulse-tube cryocooler by addressing one of its primary performance limitations, namely the performance of the regenerator at low temperatures. Our proposed regenerator uses an innovative non-rare-earth material to achieve a very high volumetric specific heat; it also has a novel configuration for high thermal and fluid performance. The regenerators large heat capacity, small void volume, and low flow restriction will substantially improve the thermal efficiency of low-temperature pulse-tube cryocoolers. In Phase I, we proved the feasibility of our approach by (1) optimizing the regenerator matrix material and flow configuration, (2) developing microfabrication procedures for the regenerator, (3) calculating thermal and fluid flow performance in the regenerator by CFD simulation, and (4) assessing the performance of a pulse-tube cryocooler using our regenerator. In Phase II, we will optimize the regenerator fabrication method, and then fabricate and test a full-size regenerator in prototypical environments.
Benefit: The military applications for pulse-tube cryocoolers include tactical coolers for low-temperature superconductor electronics, and cryocoolers for space-based communications, surveillance, missile detection, and missile tracking systems. Scientific applications include cryocoolers for space based infrared and X-ray observatories. Commercial applications include cooling systems for communication satellites; superconducting instruments, digital filters, and magnets; MRIs; SQUIDs; and data converters for next-generation wireless communications.
Keywords: regenerator, cryocooler, Pulse-Tube Cryocooler