CN115143650A

CN115143650A - A self-cleaning solar collector

Info

Publication number: CN115143650A
Application number: CN202210518287.1A
Authority: CN
Inventors: 程君林; 李天乐; 徐洁燕; 姚玉婷
Original assignee: Jiangsu University of Science and Technology
Current assignee: Jiangsu University of Science and Technology
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2022-10-04
Anticipated expiration: 2042-05-13
Also published as: CN115143650B

Abstract

The invention discloses a self-cleaning solar heat collector, which comprises a cover plate, a heat absorbing plate and a thermal insulation layer. The heat collecting medium in the gap is a nano-magnetic fluid, and the heat-collecting tube is provided with a magnet in parallel. Under the action of the magnetic force, the nano-magnetic fluid rotates perpendicular to the flow direction, fully absorbing the heat from the heat absorbing plate, thereby improving the solar collector. heat collecting capacity. In addition, the present invention also has a rotating tie in the inner tube. When the rotating tie rotates, it drives the fluid in the tube to generate a secondary flow, so that the fluid in the tube can fully absorb heat; Self-cleaning to solve the problem of scaling in the tube. The invention has the advantages of simple structure, easy installation and wide application range.

Description

Self-cleaning solar heat collector

Technical Field

The invention relates to a heat collector, in particular to a self-cleaning solar heat collector.

Background

The solar heat collector is a device for absorbing solar radiation energy and transferring heat to a working medium, and is a special heat exchanger, and the flat plate type solar heat collector is a basic component for low-temperature heat utilization of solar energy and is also a leading product of the solar energy market in many countries in the world all the time. The basic working principle of the flat-plate solar collector is very simple, sunlight irradiates a heat absorbing body coated with an absorbing layer on the surface through a transparent cover plate, and most solar radiation energy is absorbed by the heat absorbing body, converted into heat energy and transferred to working media in a fluid channel. Thus, the cold working medium from the bottom inlet of the heat collector is heated by solar energy in the fluid channel, the temperature is gradually increased, and the heated hot working medium carries useful heat energy from the upper outlet of the heat collector and is stored in the storage tank for standby. Flat plate type heat collectors have been widely used in various fields such as domestic water heating, swimming pool heating, industrial water heating, building heating and air conditioning. The water heater formed by the solar heat collector components is a flat-plate type solar water heater. Compared with other types of flat plate solar heat collectors, the wing tube type solar heat collector has the main advantages of good welding structure and high heat exchange efficiency. However, the finned tube type solar heat collector can only conduct to the part close to the heat absorbing plate when the heat absorbing plate conducts heat to the heat collecting working medium in the calandria, the temperature change of the heat collecting working medium far away from the heat absorbing plate is not large, the temperature difference of the heat collecting working medium in the tube is large, the heat collecting working medium in the tube flows insufficiently, and therefore the heat exchange efficiency is greatly reduced.

Disclosure of Invention

The invention aims to: the invention aims to provide a self-cleaning solar heat collector for improving the heat exchange effect.

The technical scheme is as follows: the self-cleaning solar heat collector comprises a cover plate, a heat absorbing plate and a heat insulating layer, wherein the heat absorbing plate comprises heat collecting calandria tubes, the heat collecting calandria tubes are double-layer tubes, fluid in an inner tube is water, a heat collecting working medium in a tube gap is nano magnetic fluid, the heat collecting calandria tubes are parallelly provided with magnets, and the nano magnetic fluid rotates perpendicular to the flow direction under the action of magnetic force.

Under the action of an external magnetic field, the nano magnetic fluid can rotate in a direction perpendicular to the flow direction, so that the heat absorption plate and the nano magnetic fluid in the pipe gap can exchange heat fully, the temperature of the nano magnetic fluid in the pipe gap is distributed uniformly, and the heat transfer performance is greatly improved. The fluid in the inner tube of the heat collection calandria is water, the temperature is raised under the heating of the heat collection working medium (nano magnetofluid), and the heated fluid is spontaneously discharged from the upper end of the heat collector and stored in the storage tank for later use.

Preferably, two bearings are arranged in the inner pipe, each bearing is installed in the inner pipe through a supporting radial plate, a spiral link is arranged between the two bearings, and when the spiral link rotates, the inner water is driven to generate secondary flow. When the fluid in the pipe reaches a certain flow velocity, the spiral twisted belt can be driven to rotate, so that secondary flow perpendicular to the main flow direction is generated, and the water in the pipe can sufficiently absorb heat; meanwhile, due to the influence of secondary flow generated by rotation of the spiral twisted belt, water in the pipe continuously washes the pipe wall, self-cleaning in the pipe can be realized, and the problem of scaling in the pipe is solved.

Preferably, the support web is streamlined.

Preferably, the absorber plate further comprises a header and a heat transfer flat plate, two ends of the heat collection calandria are fixed with the header through welding, and the heat collection calandria and the heat transfer flat plate are made of copper materials.

Preferably, the surfaces of the heat collecting calandria and the heat transfer flat plate are coated with solar selective absorption coating.

Preferably, the heat collecting tube and the magnet are positioned in a cavity between the heat absorbing plate and the heat insulating layer.

Preferably, the cover plate is transparent tempered glass.

The working principle is as follows: the spiral twisted band is inserted into the inner pipe, and when fluid in the pipe reaches a certain flow velocity, the spiral twisted band can be driven to rotate, so that secondary flow perpendicular to the main flow direction is generated, and the fluid in the pipe can fully absorb heat; meanwhile, due to the influence of secondary flow generated by the rotation of the spiral twisted belt, fluid in the pipe continuously scours the pipe wall, so that self-cleaning in the pipe can be realized, and the problem of scaling in the pipe is solved; and the nanometer magnetic fluid is used as a heat collection working medium and exerts a magnetic field effect, so that the purpose of autonomous rotation of the heat collection working medium in a pipeline is achieved. The nanometer magnetic fluid is a new functional material, and is a stable colloidal liquid formed by mixing magnetic solid particles with nanometer-scale (below 100 nanometers) diameter, base carrier liquid (also called medium) and surfactant. The nanometer magnetic fluid has liquid flowability, so that it may be used as heat collecting medium to exchange heat, and has the magnetism of solid magnetic material to move automatically in magnetic field. The nano magnetic fluid can rotate in the tube by itself only by controlling the proportion of the magnetic solid particles in the nano magnetic fluid or the magnetic force of the magnet, and the heat from the heat absorbing plate is fully received. Meanwhile, the magnetic nano fluid transfers the heat absorbed from solar radiation to the water in the inner pipe, the water density with the increased temperature is lower than that of cold water, and therefore, the cold water is pumped into the upper water tank for storing hot water under the action of gravity difference of the cold water and the hot water, and the water is used for domestic water of residents.

Has the advantages that: compared with the prior art, the invention has the remarkable advantages that: 1. the heat exchange efficiency of the heat collector is improved; 2. self-cleaning in the pipe is realized, and the problem of scaling in the pipe is solved; 3. is easy to be applied to the prior traditional solar heat collector.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a cross-sectional view of the present invention;

FIG. 3 is a schematic diagram of a self-rotating device structure;

FIG. 4 is a top view of the rotating device;

FIG. 5 is a schematic cross-sectional view of a support web.

Detailed Description

The invention will be further explained with reference to the drawings.

The self-cleaning solar heat collector comprises a cover plate 1, a heat absorbing plate 2 and a heat insulating layer 5, wherein the heat absorbing plate 2 comprises a heat collecting calandria 3, a collecting pipe and a heat transfer flat plate, the heat collecting calandria 3 is formed by tiling a plurality of copper pipes, and two ends of the heat collecting calandria 3 are fixed with the collecting pipe through welding. The heat collection calandria 3 is a double-layer tube, water is filled in the inner tube, the heat collection working medium in the tube gap is nano magnetic fluid, the heat collection calandria 3 is provided with magnets 4 in parallel, and the nano magnetic fluid rotates perpendicular to the flow direction under the action of magnetic force. The heat collecting working medium with lower temperature exchanges heat with the heat absorbing plate 2, and the heat exchange efficiency of the heat absorbing plate and the heat collecting working medium in the pipeline is improved.

A helical twist band 8 is inserted into the inner tube, and the helical twist band 8 is fixed in the inner tube through a streamline support spoke plate 6 and a bearing 7, so that the helical twist band can rotate freely. The helical twist causes spontaneous rotational movement of the water in the pipe as it flows within the inner pipe.

The heat preservation layer 5 is embedded in the shell and plays a role in heat preservation. The cover plate 1 is made of transparent glass to reduce the attenuation of solar radiation, and holes for inserting the headers are left in the upper and lower portions of the housing. The glass cover plate is linked with the shell by a glass pressing strip. The periphery of the shell is provided with an aluminum alloy frame, and the bottom of the shell is provided with galvanized iron sheets.

The magnet 4 is a permanent magnet, the nano magnetic fluid shows magnetism under the action of a magnetic field generated by the permanent magnet and can move automatically, so that the nano magnetic fluid serving as a heat collection working medium in the tube is uniformly heated, and the heat exchange efficiency can be improved.

The heat absorbing plate 2 is a main part of the flat plate type solar heat collector, absorbs the radiation energy of the sun and transfers the heat to a heat transfer working medium (nano magnetofluid). The heat collection calandria 3 and the heat transfer flat plate 2 are both made of copper materials, and the surfaces of the heat collection calandria and the heat transfer flat plate are coated with solar selective absorption coatings. The heat collecting tube and the magnet are positioned in the cavity of the heat absorbing plate and the heat insulating layer.

Based on a flat plate type solar heat collector, the spiral twisted band is inserted into the heat collecting calandria, and when fluid in the calandria reaches a certain flow rate, the spiral twisted band can be driven to rotate, so that secondary flow perpendicular to the main flow direction is generated, and the fluid in the calandria can fully absorb heat; meanwhile, due to the influence of secondary flow generated by the rotation of the spiral twisted belt, fluid in the pipe continuously scours the pipe wall, so that self-cleaning in the pipe can be realized, and the problem of scaling in the pipe is solved; and the nanometer magnetic fluid is used as a heat collection working medium and exerts a magnetic field effect, so that the purpose of autonomous rotation of the heat collection working medium in a pipeline is achieved. The heat collecting working medium is nano magnetic fluid, namely magnetic liquid, ferrofluid or magnetic liquid, is a novel functional material, has the liquidity of liquid and the magnetism of a solid magnetic material, and is stable colloidal liquid formed by mixing magnetic solid particles with the diameter of nano magnitude (less than 100 nanometers), base carrier liquid (also called medium) and a surfactant. The nanometer magnetic fluid has liquid flowability, so that it may be used as heat collecting medium to exchange heat and may move automatically in magnetic field. The nano magnetic fluid can be uniformly heated by only controlling the proportion of the magnetic solid particles in the nano magnetic fluid or the magnetic force of the magnet.

Claims

1. A self-cleaning solar collector, comprising a cover plate (1), a heat absorbing plate (2), and a thermal insulation layer (5), wherein the heat absorbing plate (2) comprises a heat collecting pipe (3) ), the heat collector tube (3) is a double-layer tube, the fluid in the inner tube is water, the heat collector working medium in the tube gap is a nano-magnetic fluid, and the heat collector tube (3) is provided with a magnet (4) in parallel. Under the action of magnetic force, the nano-magnetic fluid rotates perpendicular to the direction of flow.

2. The self-cleaning solar heat collector according to claim 1, characterized in that, two bearings (7) are arranged in the inner tube, and each bearing is installed in the inner tube through a supporting web (6), and the two A spiral tie (8) is arranged between the bearings (7), and when the rotating tie (8) rotates, it drives the water in the pipe to generate a secondary flow.

3. The self-cleaning solar heat collector according to claim 3, characterized in that the supporting webs (6) are streamlined.

4. The self-cleaning solar heat collector according to claim 1, characterized in that, the heat absorbing plate (2) further comprises a header and a heat transfer flat plate, and both ends of the heat collecting pipe (3) are welded to the header. Fixed, the heat collecting pipe (3) and the heat transfer plate are made of copper.

5 . The self-cleaning solar heat collector according to claim 4 , characterized in that, the surfaces of the heat collecting pipes ( 3 ) and the heat transfer flat plate are both coated with solar selective absorbing paint. 6 .

6 . The self-cleaning solar heat collector according to claim 1 , wherein the heat collecting tube ( 3 ) and the magnet ( 4 ) are located in the cavity of the heat absorbing plate ( 2 ) and the thermal insulation layer ( 5 ). 7 .

7 . The self-cleaning solar heat collector according to claim 1 , wherein the cover plate ( 1 ) is made of transparent tempered glass. 8 .