A compressed-air energy storage system according to embodiments of the present invention comprises a reversible mechanism to compress and expand air, one or more compressed air storage tanks, a control system, one or more heat exchangers, and, in certain embodiments of the invention, a motor-generator. The reversible air compressor-expander uses mechanical power to compress air (when it is acting as a compressor) and converts the energy stored in compressed air to mechanical power (when it is acting as an expander). In certain embodiments, the compressor-expander comprises one or more stages, each stage consisting of pressure vessel (the “pressure cell”) partially filled with water or other liquid. In some embodiments, the pressure vessel communicates with one or more cylinder devices to exchange air and liquid with the cylinder chamber(s) thereof. Suitable valving allows air to enter and leave the pressure cell and cylinder device, if present, under electronic control.

Compressed air energy storage system utilizing two-phase flow to facilitate heat exchange

The composition of worldwide energy consumption is undergoing tremendous changes due to the consumption of non-renewable fossil energy and emerging global warming issues. Renewable energy is now the focus of energy development to replace traditional fossil energy. Energy storage system (ESS) is playing a vital role in power system operations for smoothing the intermittency of renewable energy generation and enhancing the system stability. We divide ESS technologies into five categories, mainly covering their development history, performance characteristics, and advanced materials. Biomass storage and gas storage are also discussed, which are not considered in most reviews. After detailed research, the rapid development of each technology in recent years is introduced, and some representative research works are surveyed. We comprehensively summarized the advantages and disadvantages of various ESS technologies and presented several evaluation indicators for quantitative analysis. Hybrid ESS is also considered based on the complex market demand. Then, we investigate the applications of various ESS technologies as short-term, medium-term, and long-term storages in power systems, covering the power generation, transmission and distribution, and end-user. Finally, this paper reviews global developing trends, and identifies critical challenges and promising opportunities.

A review of technologies and applications on versatile energy storage systems

Methods and systems for low emission power generation in hydrocarbon recovery processes are provided. One system includes integrated pressure maintenance and miscible flood systems with low emission power generation. An alternative system provides for low emission power generation, carbon sequestration, enhanced oil recovery (EOR), or carbon dioxide sales using a hot gas expander and external combustor. Another alternative system provides for low emission power generation using a gas power turbine to compress air in the inlet compressor and generate power using hot carbon dioxide laden gas in the expander. Other efficiencies may be gained by incorporating heat cross-exchange, a desalination plant, co-generation, and other features.

Low emission power generation and hydrocarbon recovery systems and methods

A system for managing a supplemental gas supply in a breathing assistance system configured to provide breathing assistance to a patient includes a temperature sensor and a control system. The temperature sensor is configured to measure a temperature associated with a breathing assistance system configured to deliver a first gas and a supplemental gas toward a patient. The control system is configured to automatically control the flow of the supplemental gas based at least on the monitored temperature.

Supplemental gas safety system for a breathing assistance system

The invention relates to methods and systems for the storage and recovery of energy using open-air hydraulic-pneumatic accumulator and intensifier arrangements that combine at least one accumulator and at least one intensifier in communication with a high-pressure gas storage reservoir on a gas-side of the circuits and a combination fluid motor/pump, coupled to a combination electric generator/motor on the fluid side of the circuits.

Systems and methods for energy storage and recovery using compressed gas

An energy storage and recovery system employs air compressed utilizing power from an operating wind turbine. This compressed air is stored within one or more chambers of a structure supporting the wind turbine above the ground. By functioning as both a physical support and as a vessel for storing compressed air, the relative contribution of the support structure to the overall cost of the energy storage and recovery system may be reduced, thereby improving economic realization for the combined turbine/support apparatus. In certain embodiments, expansion forces of the compressed air stored within the chamber, may be relied upon to augment the physical stability of a support structure, further reducing material costs of the support structure.

Storage of compressed air in wind turbine support structure

Embodiments of the present invention relate to compressed gas storage units, which in certain applications may be employed in conjunction with energy storage systems. Some embodiments may comprise one or more blow-molded polymer shells, formed for example from polyethylene terephthalate (PET) or ultra-high molecular weight polyethylene (UHMWPE). Embodiments of compressed gas storage units may be composite in nature, for example comprising carbon fiber filament(s) wound with a resin over a liner. A compressed gas storage unit may further include a heat exchanger element comprising a heat pipe or apparatus configured to introduce liquid directly into the storage unit for heat exchange with the compressed gas present therein.

Compressed gas storage unit

An energy storage system utilizing compressed gas as a storage medium, may include one or more turbines configured to convert energy in gas expansion and compression processes. One or more axial and centrifugal turbines may be used to store energy by compressing gas, and to recover energy from expanding gas. A plurality of orifices/nozzles may introduce a liquid into the gas as a heat exchange medium. Orifices/nozzles may be disposed on various surfaces of a turbine and/or in a separate mixing chamber flowing to a turbine. Structures of the turbine may be designed to mitigate damage caused by liquid injection, for example the turbine blades may be flexible and/or comprise impact-resistant materials.

Compressed gas energy storage system using turbine

Embodiments of the present invention use compressed air to store and deliver electrical, mechanical, and/or thermal power with high round-trip efficiency. Various embodiments may be scalable for use in a variety of environments—from wind farms to power plants to motor vehicles. An energy storage system according to the present invention can operate as a stand-alone storage system that connects electrically to the grid, it can be tightly integrated with a wind turbine, and/or it can be co-located with a thermal power generation facility and operate with even higher efficiency by scavenging low-grade waste heat.

Danielle A. Fong

Papers

Compressed air energy storage system utilizing two-phase flow to facilitate heat exchange

Storage of compressed air in wind turbine support structure

Compressed gas storage unit

Compressed gas energy storage system using turbine

Compressed gas energy storage system