Abstract: An expander unit of a cryogenic refrigerator device includes a moving assembly with a porous regenerative heat exchanger configured to move back and forth along a longitudinal axis. A magnetic spring assembly includes a stationary magnetic assembly fixed to the cold finger base that includes one or more magnetic rings fixedly arranged about a bore. A movable magnetic assembly includes one or more movable magnetic rings fixed to the moving assembly. An outer lateral dimension of each of the movable magnetic rings is less than an inner lateral dimension of the bore. The stationary magnetic assembly and the movable magnetic assembly are configured such that, when the moving assembly is displaced along the longitudinal axis from an equilibrium position, attractive and repulsive forces between the movable magnetic assembly and the stationary magnetic assembly yield a restoring force that is directed to restore the moving assembly to the equilibrium position.

Abstract: A process for producing compressed hydrogen gas including: electrolysing water to produce hydrogen gas, and compressing the hydrogen gas in a multistage compression system including: a centrifugal compression stage and a recycle system for recycling a portion of the hydrogen gas from a product end to a feed end of the centrifugal compression stage; wherein hydrogen gas feed is fed to the feed end at a pre-determined feed temperature and pressure and mole fraction of water; wherein a portion of the hydrogen gas is removed from the product end, reduced in pressure in the recycle system to the pre-determined feed pressure and is then recycled to form at least part of the hydrogen gas feed to the centrifugal compression stage; and further including cooling hydrogen gas comprising the reduced pressure hydrogen gas such that the water mole fraction in the hydrogen gas feed is at the pre-determined water mole fraction.

Abstract: A Stirling engine can take advantage of adiabatic compression (which heats working gas leaving the cold cylinder) and adiabatic expansion (which cools working gas leaving the hot cylinder) to increase efficiency. In some implementations, partially-heated gas leaving the cold cylinder and partially-cooled gas leaving the hot cylinder can be routed directly to a regenerator using bypass paths that are opened using one-way valves. The resultant relatively reduced temperature difference across the regenerator, e.g., as compared to a typical Stirling engine, can reduce thermal loss and improve efficiency. In some implementations, the compression ratios of the Stirling engine can be adjusted such that the temperature of the adiabatic heated gas is the same or higher than the temperature of the adiabatic cooled temperatures, thus eliminating the need for a regenerator.

Abstract: The rotary dipole active magnetic regenerative refrigerator (10) of the present invention comprises a stationary first regenerative magnetic bed (12) positioned within a stationary first inner dipole magnet (14), a stationary second regenerative magnetic material bed (16) positioned within a stationary second inner dipole magnet (18), an outer dipole magnet (20) that rotates on a longitudinal axis and encloses the inner dipole magnets (14, 18), a cold heat exchanger (22), hot heat exchangers (24, 26), a fluid displacer (28), and connective plumbing through which a heat transfer fluid is conveyed.