A phase-change heat storage device, a solar heat utilization system using the device, and its operation mode

Abstract

The invention relates to a phase change heat storage device, a solar heat utilization system employing the same and an operating mode of the solar heat utilization system, and provides a heat storage device with good heat storage property and high exergy, and the heat storage device is applied to a solar heat utilization system. The heat storage device adopts a plurality of serially connected independent heat storage units to realize temperature gradient heat storage and utilizes latent heat of a heat storage medium during heat storage to improve the heat storage effect and the heat utilization ratio, is simple in structure and allows the heat storage units to be flexibly adjusted as required. According to the invention, the heat storage device is also applied to the solar heat utilization system, latent heat and sensible heat storage capability of the heat storage medium are fully utilized, the required amount of the heat storage medium is reduced, the structure is simplified and the solar exergy is improved.

Description

technical field [0001] The invention relates to a heat exchange device, in particular to a phase-change temperature gradient heat storage device, a solar heat utilization system using the phase-change temperature gradient heat storage device, and an operating mode of the system. technical background [0002] Among many new energy sources, solar energy has attracted increasing attention from all over the world due to its unique advantages such as nearly unlimited reserves, wide distribution, and clean energy. However, the energy density of solar energy is low, and affected by various factors such as seasons, climate, geographical environment, and day and night alternation, it has strong randomness, intermittentness, and instability. Therefore, the utilization of solar energy generally requires heat storage, and the unstable energy is stored and then stably released for utilization, and the solar thermal energy is converted into a heat energy that can be stored for a long time...

AI Technical Summary

Problems solved by technology

[0006] 1) Because molten salt is both a heat storage medium and a heat transfer medium, and the heat transfer medium can only be liquid, the latent heat of solid-liquid phase change of molten salt cannot be used to store heat, but only the sensible heat of molten salt can be used to store heat , so that the heat storage density is not large enough, that is, it cannot meet the requirements of item ① of heat storage technology;

[0007] 2) Because the heat storage density is not large enough, the total consumption of molten salt is relatively large, which makes the heat storage tank equipment huge, so it cannot meet the requirements of ⑤ and ⑥ items of heat storage technology

Molten salt tanks, molten salt heat exchangers, molten salt pumps and other equipment are difficult to manufacture, which increases manufacturing costs, operating costs, and engineering costs

[0010] 2) High requirements for accessories

[0011] 3) System security is low

Therefore, the above three currently more advanced heat storage devices cannot simultaneously meet the six core requirements of heat storage technology, so it is difficult to use them to transform traditional solar thermal utilization systems

Images