US 10,920,668 B2Granted

Energy storage system

AssigneeCheesecake Energy Ltd.

InventorsSeamus Garvey, Bruno Cárdenas, Bharath Kantharaj, Michael Simpson, Andrew Pimm, James Garvey, Paul Codd

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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. Some provision is also present whereby other fluid can be introduced into the expansion process in addition to the air that was compressed via the multi-stage compressor facility.

Claims13

Dependent claims

An energy storage system comprising:

an approximately isobaric storage volume for storing compressed air at constant pressure;
a multi-stage gas compressor configured to compress air that has been heated to a first temperature, the compression being such that the air leaving each compression stage reaches a second temperature;
an expander operable to extract work from gas entering the expander at the second temperature such that an exhaust gas emerges at a temperature significantly lower than the first temperature, wherein the gas comprises the air from the multi-stage gas compressor;
one or more first thermal stores configured to retain heat at temperatures in a range up to the first temperature;
one or more second thermal stores configured to retain heat at temperatures in a range between the first temperature and second temperature;
a thermal capture for capturing heat from an external source for storing in the one or more first thermal stores at temperatures in a range up to the first temperature;
wherein the system is operable to store energy in a charging mode, the charging mode comprising two or more different charging processes that are independently operable;
and
wherein the two or more charging processes comprise:
a first charging process in which the air is compressed in the multi-stage compressor to fill the storage volume with pressurized gas and the second thermal store is simultaneously filled with heat;
and
a second charging process in which the first thermal store is filled with heat;
wherein a total mass of gas expanded in the expander in a discharging mode is greater than a total mass of gas compressed in the multi-stage gas compressor in the first charging process.

10 more elements

A method of storing and releasing energy, the method comprising:

heating air to a first temperature using heat stored in a first thermal store;
pressurizing the heated air such that its temperature rises from the first temperature to a second temperature;
extracting heat from the pressurized air to cool the air from the second temperature to the first temperature and storing the extracted heat in a second thermal store;
extracting heat from the pressurized air to further cool the air from the first temperature to a third temperature and storing the extracted heat in the first thermal store;
storing the pressurized air with an approximately isobaric characteristic in a storage volume;
heating a pressurized gas from the storage volume to the first temperature using heat from the first thermal store, wherein the pressurized gas comprises the pressurized air;
heating the pressurized gas to the second temperature using heat from the second thermal store;
expanding the pressurized gas to extract work from the pressurized gas such that the pressurized gas is cooled from the second temperature to a lower temperature;
and
storing heat from an external heat source in the first thermal store;
wherein a total mass of the pressurized gas when expanded is greater than a total mass of the pressurized air.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/781,040Filed 5 Dec 2016
Priority: GB 1521372.13 Dec 2015
Published: US 2019/0003383 A13 Jan 2019
Granted: 16 Feb 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

F02C 6/16
Gas-turbine plants having means for storing energy, e.g. for meeting peak loads: for storing compressed air
F02C 3/04
Gas-turbine plants characterised by the use of combustion products as the working fluid: having a turbine driving a compressor
F03G 6/071
Devices for producing mechanical power from solar energy: with energy storage devices
F03G 6/092
Devices for producing mechanical power from solar energy: using heat pumps, e.g. solar assisted heat pumps