Quasi-isobaric discharge isothermal compression energy storage system and method utilizing condensable gas phase change

Abstract

The invention discloses a quasi-isobaric discharge isothermal compression energy storage system and method utilizing condensable gas phase change, and aims to solve the problem that an existing isothermal compression air energy storage system does not have the approximate isobaric discharge capacity due to the fact that a single-tank-structure pressure vessel is adopted. Based on the basic principle of an isothermal compression air energy storage technology, water-insoluble condensable gas is adopted as an energy storage working medium, a double-tank-structure pressure vessel and other measures are taken, by means of a liquid piston, spray cooling and other means, hydraulic machinery is used for replacing pneumatic machinery, approximate isobaric discharge of the isothermal compression gasenergy storage system utilizing a condensable gas phase change behavior is achieved, approximate stable power output is provided for special loads, and the system and the method have important practical significance in the aspects of improving the performance of the compression gas energy storage technology, widening the application field of the compression gas energy storage technology and the like.

Description

technical field [0001] The invention belongs to the technical field of physical energy storage, and in particular relates to a quasi-isobaric discharge isothermal compression energy storage system and method utilizing phase transition of condensable gas. Background technique [0002] With the continuous depletion of fossil energy reserves and the increasingly serious problem of environmental pollution, green and low-carbon renewable energy has received great attention. However, due to the intermittent and fluctuating characteristics of renewable energy, the grid-connection problem is more prominent, which makes the phenomenon of "abandoning wind, abandoning light, and curtailment" common at this stage. Energy storage technology can realize the spatio-temporal management of fluctuating renewable energy and help to improve the grid-connected capacity level of renewable energy. [0003] As an energy storage technology based on the gas turbine cycle, traditional compressed air ...

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Problems solved by technology

[0008] First, due to the single-tank hydraulic accumulator structure of this type of system, the pressure of the air in the tank will gradually decrease with the expansion process during the energy release process, which will lead to the reduction of the water head of the turbine and the water flowing through the turbine. The water flow and output power are also reduced at the same time, and it is impossible to achieve approximate equal pressure discharge, and it cannot provide approximately stable output power for special loads, which limits the application range of the system

[0009] Second, the system uses air as the energy storage medium, and there is no phase change process during the entire energy storage and energy release process. At the same power / energy level, a larger gas storage volume is required, which reduces the energy storage density of the system.

However, the current mainstream isothermal compressed air energy storage technology adopts a single-tank hydraulic accumulator structure, so that the system cannot provide approximately isobaric expansion when releasing energy, and cannot obtain approximately stable output power, which limits this small-scale Possibility of energy storage technology as emergency power supply for special loads

In addition, the isothermal compressed air energy storage technology uses air as the energy storage medium, and there is no phase change process in the whole process, which limits the performance improvement of this type of system

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