Abstract: The present invention relates to a gas storage apparatus and method, and more specifically to liquid air energy storage and its use to facilitate both Demand Side Reduction (DSR) and the use of reduced-cost electricity by industrial compressed-air users. A related electricity generating apparatus and method is also disclosed. The apparatus and method use a first sensible heat coolth store and second latent heat coolth store to first reduce the gas in temperature and then to change it into a liquid phase. Coolth top up devices are also disclosed.

Abstract: A magnetic change speed gearbox his described for use in a downhole assemblies having a higher speed shaft supported by a gas bearing. The downhole assembly may be one comprising a motor driving a compressor by way of a step-up magnetic gearbox or one comprising a gas turbine driving a pump by way of a step-down magnetic gearbox.

Abstract: A multi-stage compressor comprises a variable speed electrically driven rotodynamic compressor stage connected in series with and upstream of a water lubricated screw compressor stage and an intercooler arranged between the two compressors to reduce the temperature of gas entering the screw compressor stage. In the invention, the intercooler is a water spray intercooler, the water supply of which is shared with that of the water lubricated screw compressor.