A 2 K Active Magnetic Regenerative Refrigeration System for Remote Cooling.

Abstract

This paper reports on the development of an Active Magnetic Regenerative Refrigeration (AMRR) system for space applications. The AMRR can continuously provide remote/distributed cooling at about 2 K and reject heat at temperatures higher than 15 K. The AMRR employs a reversible circulator to circulate helium bi-directionally through magnetic regenerators. The circulating flow facilitates the heat transfer in the magnetic regenerators. The circulator uses self-acting gas bearings for reliable and vibration-free operation. The AMRR also uses structured-bed regenerators with microchannels for high thermal performance. Demonstrations to date have shown the ability of the circulator to operate at high speeds and low sub-atmospheric pressures. Hardware fabrication for the circulator and its demonstration are near completion, while development of the fabrication method for the regenerator is in progress. The results of this research show that the AMRR system is very attractive for space applications. The AMRR will be very reliable and vibration free. The predicted COP of the AMRR system is about 35% of a Carnot cycle with cryogenic heat sinks. The system can operate at the very short cycle period of 10 seconds to achieve a large cooling capacity. The AMRR�s ability to provide remote/distributed cooling not only allows flexible integration with payload(s) and spacecraft, but also reduces the mass of the required magnetic shields.