Solar heat storage and high temperature gas generating system with working medium being flowing sand

Abstract

A solar heat storage and high temperature gas generating system comprises a sun-tracking light concentrating device (1), a heat storage tank (2) and a heat exchange device (3), with the working medium being flowing sand (5). The flowing sand (5) is heated by the sun-tracking light concentrating device (1), and is transported into the heat storage tank (2). The flowing sand (5) is exported from the heat storage tank (2) steadily, thereby transferring heat to the high pressure gas or liquid (6) which is to be heated in the heat exchange device (3) and generating high temperature and pressure gas. The system has the advantages of good heat storage effect, large heat storage volume, high heat exchange efficiency and low operation cost.

Description

TECHNICAL FIELD[0001]The present invention is related to a system and a method to store solar energy, in addition, the invention deals with a system and a method of storage of solar-generated hot gas. In particular, the invention relates to systems for solar heat storage and high temperature gas generation with flowing sand as medium.PRIOR ART[0002]In order to achieve large-scale application of solar energy, two key issues are solar energy storage and reduce operating costs. Heated medium by solar concentrator can produce high temperature and high pressure gas (such as air or steam), driving turbines turbine power generation or for industrial use.[0003]In the solar photo-thermal systems, the solar energy is stored in a form of thermal energy. It is known as the best way to store solar energy. However, to achieve low cost, long-lasting, mass thermal storage, it is critical to find out storage medium that is cheaper, high-temperature resistant, and easy to realize heat of exchange.[00...

AI Technical Summary

Benefits of technology

[0013]The object of this invention is to provide kinds of solar heat storage and high temperature gas generation systems with a flowing sand as medium, with advanta

Problems solved by technology

In order to achieve large-scale application of solar energy, two key issues are solar energy storage and reduce operating costs.

One advantage of liquid media is that its liquidity is very good while the problems are that when the volume is large, the container has to endure higher lateral pressure at a high temperature, resulting in a high cost.

In addition, molten metal salt has a corrosion problem, and the heat conduction oil and sodium metal are quite expensive.

Moreover, for sodium metal, it is not easy to prevent leakage, resulting in security issues.

These shortcomings result in that liquid-storage media are too expensive to be used in thermal energy storage systems.

Solid thermal storage media, such as rock, soil, concrete, with advantages being low cost, have disadvantage of poor liquidity, which lead to heat exchange difficult.

(1) The collector did not consider solar concentrator, so that the energy losses by convection and radiation are large due to large exposed area. Therefore, the highest temperature of the heated particulate matter cannot be too high to be applied directly to the high-temperature solar thermal system and thus cannot be used to effectively power or as an industrial power.

(2) Sand surface is usually light colors, when directly used to absorb sunlight, high reflection rate of sunlight leads to larger energy losses and lower efficiency.

(3) Only a simple cylindrical heat storage tank is given. When its volume is increased, side walls withstand very high pressure in the horizontal direction along the walls. To overcome it, one has to increase the wall thickness. It results in increase of the heat stress, manufacture costs so that one is not able to produce low-cost thermal storage tank. Usually, to a fluid, within a container, the sidewall grazing pressure is proportional to the ratio of the diameter and the thic

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