Abstract: A system comprising two or more thermal stores, a single store for pressurised air and a means of collecting relatively low-grade heat offers the potential for an energy storage system that achieves two desirable aims at the same time: (i) the total exergy that may be released when a given pressurised air store is discharged is maximised and (ii) the ratio between the exergy extracted and the work invested in compressing the air via a multi-stage compressor is also increased by exploiting some source of low-grade heat to augment the thermal content of several thermal stores. The system comprises a compressed air energy storage system which tends, in any one fill-empty cycle of the pressurised air store, to pump heat upwards in temperature from lower-grade stores to the highest-grade thermal store as well as a thermal capture subsystem that can augment the heat content of the lower-grade thermal stores.

Abstract: A system comprising two or more thermal stores, a single store for pressurised air and a means of collecting relatively low-grade heat offers the potential for an energy storage system that achieves two desirable aims at the same time: (i) the total exergy that may be released when a given pressurised air store is discharged is maximised and (ii) the ratio between the exergy extracted and the work invested in compressing the air via a multi-stage compressor is also increased by exploiting some source of low-grade heat to augment the thermal content of several thermal stores. The system comprises a compressed air energy storage system which tends, in any one fill-empty cycle of the pressurised air store, to pump heat upwards in temperature from lower-grade stores to the highest-grade thermal store as well as a thermal capture subsystem that can augment the heat content of the lower-grade thermal stores.

Abstract: In one embodiment, the invention provides a winch including a frame and a drum rotatably supported by the frame having an exposed portion not covered by the frame. A prime mover is adapted to rotate the drum and a flexible tension member is adapted to be wound about the drum as it rotates. As it rotates, the flexible tension member defines a takeoff angle with respect to the drum. A drum guard is supported by the frame, covering substantially the entire exposed portion of the drum, and includes a plurality of guard panels, wherein at least one of the guard panels is removable to define a window through which the flexible tension member extends for substantially any takeoff angle.