SBIR-STTR Award

An innovative regenerator useable in stirling, pulse tube, Gifford-Mcmahon and sibling cycle cryocoolers is proposed. It will offer improved performance in terms of reliability, uniformity, cost and efficiency. The regenerator will be fabricated with available materials and techniques used in an entirely new way. The material is stainless steel foil. The technique creates precise patterns of channels on its surface and patterns of slots that penetrate the whole depth of the foil. The processed foil is then wound in jelly-roll fashion and inserted into the regenerator housing. With flow channels and slots properly shaped and spaced, regenerator ineffectiveness is expected to be less than half of that experienced in woven screen regenerators. The flow passages through the proposed regenerator are uniform, reducing degradation of performance due to contamination. The objective of phase i is to develop the computational tools needed to determine the optimal pattern of channels and slots. The computational tools will be created by modifying and combining several existing computer models to address the specifics of micro-channel and micro-slot geometry. The feasibility of fabricating regenerators with that optimal pattern will also be demonstrated by building two sample regenerators.

Keywords:
Regenerator Cryocoolers

A new regenerator for cryocoolers has been invented.Analysis show that it will be superior to all cryocoolerregenerators now in use. Phase I demonstrated that theregenerator can be fabricated as conceived. The new regeneratorshould improve performance of the "Brilliant Eyes" cryocoolers bymore than 20% without modifications. New cryocoolers designedfrom scratch to utilize the new technology have the potential todouble current cryocooler performance. The new regeneratordramatically improves the ratio of heat transfer to pressure dropthrough the regenerator. Since a large part of the refrigerationeffect on current cryocoolers is dissipated in regeneratorlosses, reducing those losses results in a disproportionateimprovement in net refrigeration and coefficient of performance.Improvement in COP is particularly important for spaceapplications, where payload and power consumption are critical.Higher COP means that a smaller cryocooler can do the same job asa larger one. Higher COP is also important in tactical cryocoolerapplications where batteries are the power source; the batterieslast longer. The regenerator can be fabricated from a variety ofmaterials, including materials with high heat capacity attemperatures approaching absolute zero.