Apparatuses, systems and methods are described for a flywheel system incorporating a rotor made from a high-strength material in an open-core flywheel architecture with a high-temperature superconductive (HTS) bearing technology to achieve the desired high energy density in the flywheel energy storage devices, to obtain superior results and performance, and that eliminates the material growth-matching problem and obviates radial growth and bending mode issues that otherwise occur at various high frequencies and speeds.

A cryogenic expansion turbine system (10) includes a turbo-expander (12) configured to receive and expand a cryogenic gas feed stream (24). A rotary shaft (16) operatively connects the turbo-expander and a resistance device, such as a compressor (14) or brake. A bearing housing (18) has a bearing cooling fluid inlet port and a bearing cooling fluid outlet port. Electro-magnetic bearings (22) are positioned within the bearing housing and rotatably support the rotary shaft. A bearing cooling circuit (72) directs a stream of bearing cooling fluid (62) into the bearing housing via the bearing cooling fluid inlet port so that the electro-magnetic bearings are cooled and resulting warmed bearing cooling fluid (68) exits the bearing housing via the cooling fluid outlet port.

A superconducting motor including a rotor, a heat sink, and a bearing. The rotor includes a superconducting winding formed from a superconducting material. The heat sink is positioned within the superconducting motor to absorb heat produced by the superconducting motor. The bearing includes an inner race, an outer race, and a rolling element. The bearing rotatably supports the rotor and is thermally connected to each of the rotor and the heat sink to transfer heat from the rotor to the heat sink. The rolling element is formed from a material having, at 25 K, a thermal conductivity of 20 W/mK or more and an ultimate tensile strength of 650 MPa or more. The rolling element may be formed from a copper alloy.

A bearing and flywheel system can include a first bearing portion having an opening of a first dimension there through and a central longitudinal axis, a second bearing portion having a second dimension, the second dimension being smaller than the first dimension, and a flywheel coupled to the second bearing portion. The bearing portions can include high-temperature superconductor(s) and/or magnets. The second bearing portion can be disposed at least partially within the opening through the first bearing portion. A gap can exist between an outer surface of the second bearing portion and an inner surface of the first bearing portion. The second bearing portion can be configured to rotate relative to the first bearing portion.