LIGA-fabricated high-performance micro-channel regenerators for cryocoolers

The goal of this proposal is to fabricate highly efficient regenerators using LIGA-based micromachining techniques. Specifically, sheets having a thickness of around 1.0 millimeter will be fabricated from lead or another material with high heat capacityat cryogenic temperatures. Each sheet will contain very small diameter holes (less than 50 micrometers in diameter), with a hole density that provides a sheet porosity of around 10-20%. These sheets will be stacked to produce a regenerator that will havesuperior performance (higher COP) than existing designs (stacked wire screen mesh or packed beds of spheres). The performance improvement is expected because straight micro channels have a larger heat transfer/pressure drop ratio compared to screen meshor packed beds of spheres and because the porosity of the regenerator can be reduced to values much lower than can be achieved with the existing methods.In the Phase II effort, regenerators will be fabricated for two partners- Ball Aerospace Corporation and NIST. Each of our partners will perform experiments to determine the effectiveness of the Mezzo Systems regenerators.