Abstract: Multistage hydraulic systems and methods for converting the potential energy of a pressurized gas, particularly air, into mechanical work when operating in motor, and for producing compressed gas from the mechanical work of the rotating shaft when rotating when operating in compressor mode, by performing a successive expansion/compression of the said gas. Each of the systems comprises: a multistage Compression-Expansion Unit made of several hydraulic Compression-Expansion Modules having different capacity and integrating a gas/liquid separating heat exchanger, designed to convert pressure power into a hydraulic power and vice-versa, by performing an essentially isothermal compression/expansion of the gas; a single stage or multistage, direct or indirect, external forced-air Heat Exchanger for maintaining the active liquid at ambient temperature; and a multi-circuit, multi-displacement Hydraulic Motor/Pump for converting hydraulic power into mechanical power and vice-versa.

Abstract: Different types of energy storage systems are described, in particular hydro-pneumatic storage systems. In one, energy is stored by compressing gas in a chamber (44,45,54,55) with a liquid piston and released by gas expansion. A spray head or grid at the top of the chamber (44,45,54,55) supplies liquid as a shower through the gas being compressed or expanding in the cylinder (11,12) to maintain an isothermal condition. In another, energy is stored from an array of solar cells connected to an array of supercapacitors forming an auxiliary storage, and a main energy storage device such as a hydro-pneumatic storage system, for supply to an AC or DC network. The efficiency is improved by connecting the solar cells via the array of supercapacitors to the AC or DC network.

Abstract: Multistage hydraulic systems and methods for converting the potential energy of a pressurized gas, particularly air, into mechanical work when operating in motor, and for producing compressed gas from the mechanical work of the rotating shaft when rotating when operating in compressor mode, by performing a successive expansion/compression of the said gas. Each of the systems comprises: a multistage Compression-Expansion Unit made of several hydraulic Compression-Expansion Modules having different capacity and integrating a gas/liquid separating heat exchanger, designed to convert pressure power into a hydraulic power and vice-versa, by performing an essentially isothermal compression/expansion of the gas; a single stage or multistage, direct or indirect, external forced-air Heat Exchanger for maintaining the active liquid at ambient temperature; and a multi-circuit, multi-displacement Hydraulic Motor/Pump for converting hydraulic power into mechanical power and vice-versa.

Abstract: Different types of energy storage systems are described, in particular hydro-pneumatic storage systems. In one, energy is stored by compressing gas in a chamber (44,45,54,55) with a liquid piston and released by gas expansion. A spray head or grid at the top of the chamber (44,45,54,55) supplies liquid as a shower through the gas being compressed or expanding in the cylinder (11,12) to maintain an isothermal condition. In another, energy is stored from an array of solar cells connected to an array of supercapacitors forming an auxiliary storage, and a main energy storage device such as a hydro-pneumatic storage system, for supply to an AC or DC network. The efficiency is improved by connecting the solar cells via the array of supercapacitors to the AC or DC network.