Nanofluid direct absorption solar steam generating device and method

Abstract

The invention discloses a nanofluid direct absorption solar steam generation device and method, which integrates nanofluid direct absorption solar heat collection and steam generation. The outer tube adopts an uncoated U-shaped vacuum tube (2), and the U-shaped A casing steam generating tube (5) is provided in the vacuum tube, and the annular closed cavity between the U-shaped vacuum tube and the casing steam generating tube is filled with nanofluid (4). The evaporation medium absorbs the heat of the nanofluid in the casing steam generating tube and then vaporizes into steam and flows out. The inner tube wall of the casing steam generating tube is provided with a nozzle (7) for replenishing liquid to increase the heat transfer coefficient. The invention utilizes the light absorption characteristics of nanofluid to directly absorb solar energy and generate medium-temperature steam, while strengthening the evaporation heat exchange and heat transfer performance, fundamentally avoiding the defects of high temperature resistance and poor durability of the absorption coating of traditional collectors, and is a new method for absorbing energy. A new and efficient solar thermal collection technology that integrates heat, heat transfer, heat carrying and steam generation.

Description

technical field [0001] The invention relates to solar heat collection and belongs to the fields of solar heat utilization and steam generation. Background technique [0002] The type of medium-temperature collectors currently used is mainly a straight-through metal-glass vacuum tube structure. This structure is coated with a solar selective absorption coating on the surface of the inner tube of the heat collector. The coating absorbs solar radiation and then transfers heat energy to the inside of the tube. Heat collecting fluid, due to the poor temperature resistance and durability of the absorbent coating, the different thermal expansion coefficients of glass and metal, and the uneven heating of the tube wall in the circumferential direction during operation, it is easy to cause the heat collecting tube to rupture or leak, and the reliability and safety are low. The heat pipe vacuum tube solar collector uses the absorbing coating on the heat collecting tube wall or fins to ...

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Problems solved by technology

[0006] In order to improve the heat collection efficiency of solar energy at medium temperature and the efficiency of direct steam generation of solar energy, the invention solves the problem of poor high temperature resistance and durability of the absorbing coating of traditional solar heat collectors, and the increase of reversible loss caused by large heat transfer temperature difference. The large temperature difference can easily cause problems such as damage to the heat collecting tube. The present invention proposes a nanofluid direct absorption solar steam generating device and method, which can effectively improve the heat utilization efficiency and use solar heat to generate steam in the middle and low temperature areas.

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