Solid-liquid phase change energy storage device for separately-filled molten salt

Abstract

The invention belongs to the field of energy storage, and particularly relates to a solid-liquid phase change energy storage device for separately-filled molten salt. The solid-liquid phase change energy storage device comprises a heat preservation shell, an energy storage body, a heat storage loop and a heat release loop, wherein the energy storage body is arranged in the heat preservation shell,the energy storage body is formed by stacking a plurality of energy storage body units, the energy storage body units are composed of molten salt boxes and the molten salt separately filling the molten salt boxes, and the heat storage loop and the heat release circuit are attached to the plurality of energy storage body units. According to the solid-liquid phase change energy storage device for the separately-filled molten salt, a high-temperature molten salt solid-liquid phase change energy storage technology is adopted, the energy storage density is large, and the energy storage temperatureis high, so that the thermoelectric conversion efficiency is high; and meanwhile, a salt tank is omitted, so that the occupied area is small, and the cost is low.

Description

technical field [0001] The invention belongs to the field of energy storage, and in particular relates to a solid-liquid phase change energy storage device for dispersing and filling molten salt. Background technique [0002] The biggest problem in power grid dispatching is peak regulation. Because there is a big difference between the electricity load during the peak hours of the day and the trough hours in the second half of the night, more power should be generated during the peak hours, and less power should be generated during the trough hours. [0003] my country's current power supply mainly relies on coal-fired thermal power units to generate electricity, and thermal power units cannot be shut down at will during operation, and can only reduce the output load of the units. Due to the very limited peak-shaving capacity of thermal power units, even if the output load of the units is adjusted to the minimum load for safe operation during the valley period, the output l...

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Problems solved by technology

[0026] 1. Using low melting point potassium nitrate-sodium nitrate mixed salt liquid sensible heat energy storage, due to the limit of the maximum allowable temperature of molten salt, the energy storage temperature can not be too high, resulting in low thermoelectric conversion efficiency, resulting in most of the heat energy in thermoelectric conversion In the process, it becomes useless heat loss, and the whole energy storage system needs two large molten salt tanks, hot salt tank and cold salt tank, and because the energy storage density of molten salt sensible heat storage is low, so the amount of molten salt is large, not only The volume of the molten salt tank is large, the cost of the molten salt tank is high, the floor area is large, and the purchase cost of the molten salt is large, so the investment in the infrastructure of the entire system is very high

In addition, large molten salt tanks have high requirements on the foundation and foundation. If the uneven settlement of the foundation is too large, it will cause damage to the molten salt tank and cause major accidents

[0027] 2. If high-temperature molten salt solid-liquid phase change energy storage is used, although the energy storage temperature is high, the thermoelectric conversion efficiency is high, the amount of molten salt can be reduced, and only one molten salt tank is required, with a small footprint and low investment However, due to the fact that the high temperature resistant and corrosion resistant metal plates currently used in the manufacture of high temperature molten salt tanks cannot be solved, and the high temperature molten salt has a large volume change when there is a solid-liquid phase change for energy storage, the heat conduction of the liquid molten salt Poor performance and other characteristics make it difficult to solve the heat storage and heat release methods of high-temperature molten salt, so the solid-liquid phase change energy storage technology of high-temperature molten salt is currently immature in application and cannot be applied in engineering practice

Even if the high-temperature molten salt is made into an energy storage material with a composite structure, it cannot be applied in engineering practice at present because of its low energy storage density, and the heat storage and heat release methods are not easy to solve.

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