Method and system for increasing energy storage efficiency of compressed air by using ORC

Abstract

The invention belongs to the technical field of electric energy storage of compressed air, in particular to a method and system for increasing energy storage efficiency of compressed air by using ORC.The method comprises the following steps: during an energy storage process, compressing air and storing compression heat into a heat storage tank; during an energy releasing process, heating high-pressure air by a part of heat in the heat storage tank, wherein heated air enters an expansion machine to do work through expansion and the remaining heat of a heat storage working medium after an expansion process and the remaining partial heat in the heat storage tank are used for organic rankine cycle to generate electricity. The system comprises a compressor unit, a first heat exchanger, an airstorage tank, a second heat exchanger and an expansion unit. The first heat exchanger is connected with the heat storage tank. The heat storage tank is connected with the second heat exchanger and anorganic rankine cycle electricity-generating system. The remaining heat storage amount in a compressed air energy storage system is fully utilized. Firstly, the remaining heat is firstly used for pre-heating an organic working medium. Then, storage heat that cannot be fully used is used for reheating the working medium in order to ensure that heat is completely leveraged.

Description

technical field [0001] The invention belongs to the technical field of compressed air electric energy storage, and in particular relates to a method and a system for improving compressed air energy storage efficiency by using ORC. Background technique [0002] Compressed air energy storage (CAES) refers to the use of abundant power on the grid or unstable new energy power such as wind energy and solar energy to compress air when the electricity price is low, and seal and store the compressed high-pressure air. At this time, the high-pressure air is released and the air turbine is driven to drive the generator to generate electricity, so as to achieve the purpose of electric energy storage. In the existing compressed air energy storage system, the compressed high-pressure air is usually stored in an underground air storage room or an artificial air storage tank. [0003] The traditional CAES system needs to rely on the combustion chamber to provide heat energy to heat the hi...

AI Technical Summary

Problems solved by technology

However, this liquid compressed air energy storage system adds an air liquefaction link and a liquid pump, making the energy storage efficiency of the liquid compressed air energy storage system lower than that of the general gaseous compressed air energy storage system

Therefore, the energy storage efficiency of the LAES system is the main factor limiting its development. Although the efficiency of the AA-CAES system is higher than that of the LAES system, it is also restricted by efficiency factors.

[0005] Chinese patent CN105569753A discloses an organic Rankine cycle power generation device using waste heat in the process, but this device only uses the waste heat in the energy release process to heat the organic working fluid for power generation, because the temperature of the waste heat in the energy release process is about 50 degrees, so The ORC power generation efficiency of this device is not high, considering the cost issue, this device is not suitable for application

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