A system for air compression, storage and expansion may include a low-pressure and a high-pressure compressor, a motor, a heat storage, an air storage volume, a high-pressure and a low-pressure turbine, and a generator. The system may further include a first air path connecting sequentially the low-pressure compressor, the heat storage, the high-pressure compressor, and the air storage volume. The system may further include a second air path connecting sequentially the air storage volume, the high-pressure turbine, the heat storage, and the low-pressure turbine.

A power system of an aircraft includes a hybrid energy storage system with at least two energy storage subsystems each having a different power-energy density. The power system also includes one or more electric motors operably coupled to the hybrid energy storage system and to an aircraft engine. The power system further includes a means for controlling one or more electric power flows of the hybrid energy storage system to/from the one or more electric motors based on a modeled electric power demand associated with an engine load of one or more spools of the aircraft engine.

A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.

A system includes a gas turbine engine having a low speed spool, a high speed spool, and a combustor. The system also includes a low spool motor configured to augment rotational power of the low speed spool. The system further includes a controller configured to cause fuel flow. The controller is operable to control the low spool motor to drive rotation of the low speed spool responsive to a thrust command while the controller does not command fuel flow to the combustor.

A liquid fuel rocket engine according to one example includes a combustor, a liquid fuel repository connected to the combustor via a fuel line and a first valve, an oxidizer repository connected to the combustor via an oxidizer line and a second valve, a valve controller configured to output a valve control current to the first valve, the valve controller storing instructions for determining at least one actual minimum impulse bit of a valve based on a current profile and a voltage profile of a single operation of the first valve, and to adjust valve controls to account for the at least one actual minimum impulse bit.

The invention relates to a system and a method for storing electrical energy which are based on a closed thermodynamic cycle. They make it possible to store electrical energy in a very efficient, cost-effective, and safe manner. No environmentally hazardous or expensive materials are required. The system comprises a compressor, a turbine, and two packed-bed storage units which are operated at different temperature levels.

In order to load the packed-bed storage units, the cycle is operated as a counterclockwise heat pump process. In this process, the heat generated at the outlet of the compressor is expanded at a high temperature level into a first packed-bed storage unit and stored therein. The “cold” produced during the subsequent expansion of the gaseous working medium in a turbine is stored in a second packed-bed storage unit. This requires mechanical energy which is provided by an electrical machine. In order to discharge the energy storage system, the cycle is operated in reverse (i.e., as a clockwise cycle). Before entering the compressor, the working medium is cooled with the cold stored in the second packed-bed storage unit and, after compression, absorbs the heat from the high-temperature packed-bed storage system. The hot working medium at high pressure is expanded by means of the turbine and thus energy is generated.

An energy storage apparatus that includes at least one inlet for incoming process gas, at least one outlet for expanded process gas and a plurality of energy storage sub-systems configured to be arranged in series with each other and with a compressed gas store. The first of the plurality of energy storage sub-systems includes a first compressor, a first expander, a first thermal store and a first heat transfer device associated with the first thermal store. The second of the plurality of energy storage sub-systems includes a second compressor, at least a second expander, a second thermal store and a second heat transfer device associated with the second thermal store.

An energy storage system has a pressure vessel that is exposed to ambient temperatures and that contains a working fluid which is condensable at ambient temperatures (CWF); a liquid reservoir in communication with one of the vessels and containing a liquid that is unvaporizable in the reservoir and in the vessel; and apparatus for delivering the liquid from the reservoir to the vessel. The CWF is compressible within the vessel upon direct contact with the liquid and is storable in a liquid state after being compressed to its saturation pressure. In a method, at least some of the liquid located in the vessel is propelled by the CWF towards a turbine to produce power. In one embodiment, a module has a first vessel having at least four ports, a second vessel at ambient temperatures, and a flow control component operatively connected to a corresponding conduit for selectively controlling fluid flow.

An engine system of an aircraft includes an energy storage system, a gas turbine engine, and a controller. The gas turbine engine includes a low spool, a high spool, a low-spool generator operably coupled to the low spool, and a high-spool electric motor operably coupled to the high spool. The controller is configured to detect a braking condition of the aircraft, transfer power from the low-spool generator to the energy storage system based on the storage capacity state of the energy storage system, and transfer power to the high spool through the high-spool electric motor to support combustion in the gas turbine engine while a rotational speed of the low spool is reduced responsive to the low-spool generator extracting energy from the low spool.

A method of modifying an existing gas turbine to create a storage engine, the gas turbine having a combustor, a compressor section, and a turbine section, the method comprising modifying the compressor section of the gas turbine to form the storage engine such that air supplied to the combustor of the storage engine is heated by exhaust of the storage engine and is supplied from a remote source.