CN112303934A

CN112303934A - Active solar energy tracking heat collection device and air cylinder structure thereof

Info

Publication number: CN112303934A
Application number: CN202010170202.6A
Authority: CN
Inventors: 王素梅; 杨绪钦; 刘献福; 王湛; 陈岩
Original assignee: Shandong Besten Pneumatic Technology Co ltd; Shandong University
Current assignee: Shandong Besten Pneumatic Technology Co ltd; Shandong University
Priority date: 2020-03-12
Filing date: 2020-03-12
Publication date: 2021-02-02
Anticipated expiration: 2040-03-12
Also published as: CN112303934B

Abstract

The invention provides an active solar tracking heat collection device and a cylinder structure thereof, wherein the device comprises a water tank and a photothermal conversion element, the upper end of the water tank is of an open structure, the photothermal conversion element floats on the upper part of the water tank, the photothermal conversion element comprises a base body formed by a foaming material, a groove with an opening at the upper side is formed on the base body, a heat collection pipe box comprises a first pipe orifice and a second pipe orifice, the first pipe orifice is connected with an inlet of a left heat release pipe group, the second pipe orifice is connected with an inlet of a right heat release pipe group, an outlet of the left heat release pipe group is connected with an upper pipe, and an outlet; the first pipe orifice and the second pipe orifice are arranged on one side of the heat collecting pipe box. According to the invention, a large amount of steam is generated without the assistance of a heating device, the floating foam material supports the photo-thermal conversion layer out of the water surface, and the dissipation of the generated heat energy to the lower layer liquid through the film is inhibited, so that the evaporation efficiency of the device is improved, and the great potential of the device as a photo-thermal conversion new energy material is shown.

Description

Active solar energy tracking heat collection device and air cylinder structure thereof

Technical Field

The invention belongs to the field of solar energy, and particularly relates to a solar heat collector system.

Background

With the rapid development of modern socioeconomic, the demand of human beings on energy is increasing. However, the continuous decrease and shortage of traditional energy reserves such as coal, oil, natural gas and the like causes the continuous increase of price, and the environmental pollution problem caused by the conventional fossil fuel is more serious, which greatly limits the development of society and the improvement of the life quality of human beings. Energy problems have become one of the most prominent problems in the modern world. Therefore, the search for new energy sources, especially clean energy sources without pollution, has become a hot spot of research.

Solar energy is inexhaustible clean energy and has huge resource amount, and the total amount of solar radiation energy collected on the surface of the earth every year is 1 multiplied by 10¹⁸kW.h, which is ten thousand times of the total energy consumed in the world year. The utilization of solar energy has been used as an important item for the development of new energy in all countries of the world. However, the solar radiation has a small energy density (about one kilowatt per square meter) and is discontinuous, which brings certain difficulties for large-scale exploitation and utilization. Therefore, in order to widely use solar energy, not only the technical problems should be solved, but also it is necessary to be economically competitive with conventional energy sources.

Aiming at the structure of a heat collector, the prior art has been researched and developed a lot, but the heat collecting capability is not enough on the whole, and the problem that the operation time is long and scaling is easy to happen, so that the heat collecting effect is influenced.

In any form and structure of solar collector, there is an absorption component for absorbing solar radiation, and the structure of the collector plays an important role in absorbing solar energy.

The heat pipe technology is widely applied to the industries of aerospace, military industry and the like, and since the heat pipe technology is introduced into the radiator manufacturing industry, the design idea of the traditional radiator is changed for people, the single heat radiation mode that a high-air-volume motor is used for obtaining a better heat radiation effect is avoided, the heat pipe technology is adopted for enabling the radiator to obtain a satisfactory heat exchange effect, and a new place in the heat radiation industry is opened up. At present, the heat pipe is widely applied to various heat exchange devices, including the fields of solar energy and seawater desalination, such as the utilization of solar energy.

More than 1 ten thousand islands in China, but most of the islands cannot live due to lack of fresh water, and the number of residents is less than 500, so that the functions of island development, national defense and the like are restricted. The living environment is improved, seawater desalination becomes one of main water supply modes in severe water-deficient island areas, and the requirements of the island on continuously improved living and production water are basically met.

Aiming at the problems, the invention provides a novel solar heat collection seawater desalination system. The device takes sunlight as a driving source, generates a large amount of steam without the assistance of a heating device, and the preparation method has the advantages of simple process, non-toxic and harmless raw materials and higher repeatability. The steam generating device can efficiently utilize solar energy to prepare solar steam, and has wide commercial value and application prospect in the fields of solar power generation, seawater desalination, sewage treatment and the like.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a solar heat collection seawater desalination system. The device uses sunlight as a driving source, a large amount of steam is generated without the assistance of a heating device, the floating foam material holds the photothermal conversion layer out of the water surface, and the dissipation of generated heat energy to lower-layer liquid through a film is inhibited, so that the steam efficiency of the device is improved, and the great potential of the device as a photothermal conversion new energy material is shown. The preparation method has simple process, nontoxic and harmless raw materials and higher repeatability. The steam generating device can efficiently utilize solar energy to prepare solar steam, and has wide commercial value and application prospect in the fields of solar power generation, seawater desalination, sewage treatment and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

an active solar tracking heat collecting device, the system comprises a water tank, a photothermal conversion element, the upper end of the water tank is of an open structure, the photothermal conversion element floats in seawater on the upper part of the water tank, the photothermal conversion element comprises a base body formed by foaming materials, and a groove with an opening on the upper side is formed on the base body, the system further comprises a solar auxiliary heating device, the auxiliary heating device comprises an evaporation end and a condensation end, the evaporation end is a solar heat collecting component, the condensation end is arranged in the water tank, the solar auxiliary heating device is also a heat collecting device and comprises a heat collecting pipe box, an upper pipe and a heat releasing pipe group, the heat releasing pipe group comprises a left heat releasing pipe group and a right heat releasing pipe group, the left heat releasing pipe group is communicated with the upper pipe and the heat collecting pipe box, the right heat releasing pipe group is communicated with the upper pipe and the heat collecting pipe box, phase-change fluid is filled in the heat collecting tube box, each heat release tube group comprises a plurality of arc-shaped heat release tubes, the end parts of the adjacent heat release tubes are communicated, the heat release tubes form a series structure, and the end parts of the heat release tubes form free ends of the heat release tubes; the heat collection tube box comprises a first tube opening and a second tube opening, the first tube opening is connected with an inlet of the left heat release tube group, the second tube opening is connected with an inlet of the right heat release tube group, an outlet of the left heat release tube group is connected with the upper tube, and an outlet of the right heat release tube group is connected with the upper tube; the first pipe orifice and the second pipe orifice are arranged on one side of the heat collecting pipe box.

Preferably, a temperature detection element is arranged in the evaporation end and used for detecting the temperature in the heat collection device, the temperature detection element is in data connection with the controller, the controller extracts temperature data according to a time sequence, the temperature difference or the accumulation of temperature difference changes is obtained through comparison of the temperature data of adjacent time periods, and when the temperature difference or the accumulation of temperature difference changes is lower than a threshold value, the controller controls the heat collection tube box to stop heat collection or continue heat collection.

Preferably, the groove is filled with a foamed nickel matrix, the wall surface of the lower part of the matrix is provided with a capillary structure water delivery channel, the water delivery channel is communicated with the water body of the water tank and the foamed nickel matrix, the upper part of the groove is provided with a photothermal conversion coating, the photothermal conversion coating is connected with the foamed nickel matrix, and the buoyancy of the foaming material is larger than the gravity.

Preferably, the reflector is divided into two parts along a middle portion, the first part and the second part are respectively, the support member is a support column and is disposed at a lower portion of the heat collecting tube box, and the pneumatic telescopic rod extends from the support column and is connected to the first part and the second part for driving the first part and the second part to be separated or combined. When the first part and the second part are combined together, the reflector forms a complete reflector, and the heat collection tube box is positioned at the focal position of the reflector and used for collecting heat for the heat collection tube box; when the first part and the second part are separated, the heat collecting pipe box is not positioned at the focus of the first part and the second part, and heat is not collected to the heat collecting pipe box.

Preferably, the pneumatic telescopic rod is connected with the driver, the driver drives the pneumatic telescopic rod to stretch, the position of the focus of the reflector is changed by stretching of the pneumatic telescopic rod, and the pneumatic telescopic rod is of a cylinder structure and comprises an air inlet valve, an air cylinder, a piston cavity, an exhaust valve, a magnetic ring, a piston seal, a guide ring, a support rod and a piston; the air cylinder is communicated with the air compressor through an air inlet hole, when the piston moves upwards, the magnetic ring arranged on the piston and the upper inductor on the outer wall of the air cylinder generate electromagnetic induction, when the positions of the magnetic ring and the upper electromagnetic inductor coincide, the air inlet valve is closed, the piston stops moving, and therefore the supporting rod connected with the piston keeps a certain position to be still; when the piston moves downwards, the exhaust valve is changed into an air inlet valve and the air inlet valve is changed into an exhaust valve, the piston is pushed to move downwards by compressed air, and when the magnetic ring and the lower electromagnetic inductor are superposed, the air inlet valve is closed and the piston is still.

The invention has the following advantages:

1. the temperature difference or the accumulated temperature difference of the time periods before and after the detection of the temperature sensing element can judge that the evaporation of the internal fluid is basically saturated and the volume of the internal fluid is not changed greatly through the parameter difference, under the condition, the internal fluid is relatively stable, the vibration of the tube bundle is poor, and therefore adjustment is needed to be carried out, the tube bundle is vibrated, and heat collection is stopped. So that the fluid undergoes volume reduction to thereby realize vibration. When the pressure difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and heat collection is needed to ensure that the fluid is evaporated and expanded again, so that heat collection needs to be started.

2. Aiming at the defects in the prior art, the invention provides a pneumatic driving solar heat collection device, which drives a solar device through a cylinder structure.

3. Aiming at the defects in the prior art, the invention provides a solar heat collection seawater desalination system. The device uses sunlight as a driving source, a large amount of steam is generated without the assistance of a heating device, the floating foam material holds the photothermal conversion layer out of the water surface, and the dissipation of generated heat energy to lower-layer liquid through a film is inhibited, so that the steam efficiency of the device is improved, and the great potential of the device as a photothermal conversion new energy material is shown. The preparation method has simple process, nontoxic and harmless raw materials and higher repeatability. The steam generating device can efficiently utilize solar energy to prepare solar steam, and has wide commercial value and application prospect in the fields of solar power generation, seawater desalination, sewage treatment and the like.

4. The invention provides a preparation method of a photothermal conversion piece, and the preparation method has the advantages of simple process, no toxicity and harm of raw materials and high repeatability.

5. In the photothermal conversion element of the present invention, since the photothermal conversion layer and the lower water body are separated by the heat insulating layer, heat loss caused by heat transfer from the photothermal conversion layer to the water body is effectively suppressed in the photothermal conversion process. Meanwhile, sufficient moisture is continuously supplied to the photo-thermal conversion layer through the water conveying pipeline under the action of capillary force, so that the continuous generation of solar steam is realized. Under the irradiation of sunlight intensity, the photothermal conversion layer is rapidly heated from 18.1 ℃ to 33.5 ℃ within one minute, and is stabilized at 38 ℃ after 40 minutes. After the heat insulation layer is irradiated for 40 minutes, the temperature is only raised to 25.5 ℃ from 18.1 ℃, and the temperature is basically maintained within the room temperature. The irradiation time was extended to 90 minutes and the temperature of the photothermal conversion layer and the thermal insulation layer were still stabilized at 39.5 ℃ and 25.5 ℃ respectively. On the other hand, in the irradiation time of 90 minutes, due to the blocking effect of the photothermal conversion layer on light and the inhibiting effect of the heat insulation layer on heat conduction, the lower water body is always kept within the room temperature, and the heat loss caused by the heat dissipation to the environment through the water body is greatly reduced.

6. The invention optimizes the porosity and the aperture of the photo-thermal conversion element, and further improves the conversion efficiency.

7. The invention provides a heat collecting device with a novel structure, wherein the left and right pipe groups are connected with the same upper pipe, and compared with the two upper pipes designed in the prior art, the pressure and the flow of the left and right pipe groups can be further balanced, so that the uniform heat exchange is ensured. This application is to above-mentioned structure further improvement, reinforcing scale removal and heat transfer effect. The heat collecting effect can be improved, the heat release capacity of the heat collecting pipe is improved, and the energy consumption is reduced.

8. The invention optimizes the optimal relation of the parameters of the heat collecting device through a large amount of experiments and numerical simulation, thereby realizing the optimal heating efficiency.

Description of the drawings:

FIG. 1 is a schematic diagram of the structure inside the water tank of the seawater desalination apparatus.

Fig. 2 is a top view of a reduced graphene oxide light-to-heat conversion device.

Fig. 3 is a bottom view of the bottom of the transparent glass cover.

FIG. 4 is a front view of the heat collecting device of the present invention.

FIG. 5-1 is a front view of the heat collecting system of the present invention.

FIG. 5-2 is a front view of the heat collecting system of the present invention without collecting heat.

Fig. 5 to 3 are front views illustrating heat collection of a preferred heat collecting device according to the present invention.

FIGS. 5 to 4 are front views without heat collection of a preferred heat collecting apparatus of the present invention.

FIG. 6 is a left side view of the heat collecting device of FIG. 4 according to the present invention.

FIG. 7 is a bottom view of the heat collecting device of FIG. 4 according to the present invention.

FIG. 8 is a cross-sectional view of a preferred pneumatic device.

Fig. 9 is a schematic flow diagram of a preferred overall system.

In the figure: 1. the heat-radiating pipe comprises a heat-radiating pipe group, a left heat-radiating pipe group 11, a right heat-radiating pipe group 12,

upper pipes

2, 3, free ends, 4, free ends, 5, free ends, 6, free ends, 7, a heat-radiating pipe, 8, a heat-collecting pipe box, 9, a water tank, 10 first pipe orifices, 13 second pipe orifices, a left return pipe 14, a right return pipe 15, a 16 reflector, a 161 left side reflector, a 162 right side reflector, a 17 supporting piece, a 171 left side pneumatic telescopic rod and a 172 right side pneumatic telescopic rod; 18 a water delivery channel; 19 a substrate; 20 a foamed nickel matrix; 21 photo-thermal conversion coating, 22 hydrophobic holes, 23 water collecting grooves, 24 vapor delivery pipes, 25 vapor condensation pipes, 26 right pneumatic devices, 27 left pneumatic devices, 28 right supporting rods, 29 left supporting rods, 30 air inlet valves, 31 air cylinders, 32 piston bodies, 33 exhaust valves, 34 magnetic rings, 35 left pneumatic telescopic rods, 36 right pneumatic telescopic rods, 41 transparent glass covers, 42 grooves and 45 condensed water delivery pipes.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

In this document, "/" denotes division and "×", "denotes multiplication, referring to formulas, if not specifically stated.

As shown in fig. 1-3, a solar heat collection seawater desalination device, the device includes water tank 9, light and heat conversion component, the water tank upper end is open structure, light and heat conversion component floats on water tank 9 upper portion, light and heat conversion component includes the base member 19 that the expanded material formed, forms upside open-ended recess 42 on the base member 19, foam nickel base member 20 is filled in the recess 42, the lower part wall of base member 19 sets up capillary structure water delivery passageway 18, water delivery passageway 18 communicates the water and foam nickel base member 20 of water tank 9, the upper portion of recess 42 sets up light and heat conversion coating 21, light and heat conversion coating 21 links to each other with foam nickel base member 20, and expanded material self buoyancy is greater than gravity.

Driven by capillary action, water in the water body is transmitted to a foamed nickel matrix 20 in a foaming material matrix 19 through a water transmission channel 18, and then is transmitted to a photo-thermal conversion coating 21 on the upper surface of the foamed nickel matrix 20 through the capillary action of a porous medium of the foamed nickel matrix 20, and is subjected to heat absorption vaporization under the irradiation of sunlight to form steam. The generated steam is recovered by a recovery device. The floating substrate 19 holds the photothermal conversion layer out of the water surface, so that the dissipation of the generated heat energy to the lower water body and the surrounding environment by the film is inhibited, and the steam generation efficiency is improved.

Preferably, the upper surface of the photothermal conversion coating 21 is at the same height as the upper surface of the water body or is not more than 5 cm higher than the upper surface of the water body. Through above-mentioned facility, can make the better light and heat conversion that carries on of light and heat conversion coating 21, improve the efficiency of getting water.

Preferably, the groove 42 is circular in cross-section.

Preferably, a transparent glass cover 41 is arranged at the upper part of the water tank 9, the transparent glass cover 41 is in a circular arc structure, the glass cover comprises a water collecting tank 23 positioned at the lower side, the water collecting tank 23 comprises an inner vertical side wall, a horizontal wall extending from the bottom end of the vertical side wall to the horizontal direction, an outer vertical wall extending upwards along the other end of the horizontal wall, and a circular arc structure extending upwards and inwards along the outer vertical wall, the water collecting tank is formed among the inner vertical wall, the horizontal wall and the outer vertical wall, and a water drainage hole 22 is arranged on the horizontal wall, so that the collected fresh water in the water collecting tank is drained out, and the purpose of taking water from seawater is achieved.

Preferably, the inner wall of the circular arc structure is provided with a diversion trench, so that the steam can flow into the water collection trench in time after being condensed. As an improvement, a steam outlet pipe is arranged at the top of the transparent glass cover 41 and is connected with a cooling coil at the bottom of the water tank 9, steam is led into the cooling coil for cooling, water in the water tank 9 is preheated by utilizing heat released by steam condensation, and the water is led into a recovery device after the steam in the cooling coil is condensed into water.

Preferably, a plurality of convex lenses are arranged on the circular arc structure, and the focal points of the convex lenses are positioned on the photothermal conversion coating, so that the evaporation of the liquid is further accelerated.

The device takes the sunshine as a driving source, generates a large amount of steam without the assistance of a heating device, and mainly comprises two parts: the device comprises a reduced graphene oxide photo-thermal conversion layer and a heat insulation layer. The photothermal conversion layer is a foam nickel-based reduction graphene oxide film; the matrix is a foamed polyethylene material; the substrate 19 placed in the water tank floats on the water surface because its foam material itself has a buoyancy greater than the gravity. Driven by capillary action, water in the water tank is transported to the photothermal conversion layer in the groove of the substrate through the foamed nickel substrate and is vaporized into steam under the irradiation of sunlight. The floating matrix 19 holds the photothermal conversion layer out of the water surface, and inhibits the generated heat energy from being dissipated to the lower-layer liquid by the film, so that the steam efficiency of the device is improved, and the great potential of the device as a photothermal conversion new energy material is shown. The preparation method has simple process, nontoxic and harmless raw materials and higher repeatability. The steam generating device can efficiently utilize solar energy to prepare solar steam, and has wide commercial value and application prospect.

Preferably, the photothermal conversion coating is a foamed nickel-based reduced graphene oxide film. The photothermal conversion element is prepared by the following method:

(1) synthesis of reduced graphene oxide: adding 1000-3000mg of graphene oxide into 1000-3000mL of deionized water, respectively adding 750-9000 mg (with an interval of 250 mg) of ascorbic acid to obtain graphene dispersion, respectively stirring and performing ultrasonic treatment (preferably 40KHz, 240W) for 60 minutes in sequence, and reacting for 30 minutes at 2.45GHz, 200W and 95 ℃ by using a microwave reactor. Removing impurities on the upper layer of the obtained suspension, carrying out suction filtration, repeatedly washing with ultrapure water for three times, and carrying out vacuum freeze drying on the sample obtained by suction filtration to obtain reduced graphene oxide powder.

(2) Preparing a photothermal conversion device: 1g of reduced graphene oxide (particle size 60nm) is dispersed by ultrasonic (preferably 40KHz, 240W) treatment to a volume ratio of 1000ml to 7: 1 in a mixed solution of water and ethanol. Agarose (12.5g) and urea (125g) were added to the solution and stirring was continued at 85 ℃ for 30 min. The resulting hot suspension was then applied evenly to the surface of the nickel foam. And naturally cooling the foamed nickel matrix with the reduced graphene oxide coating, freezing the cooled foamed nickel matrix in a refrigerator at the temperature of-21 ℃ for 12 hours, and taking out the cooled foamed nickel matrix.

(3) Preparation of the substrate 3: a common foaming material plate is taken and processed into a cylinder with the size suitable for the inner diameter of a beaker, and the preferred diameter is 20cm and the height is 10 cm.

Theoretical design calculation:

and (3) testing the mass loss: the solar steam generating device is placed in a 300-plus-1000 mL water-containing beaker, the beaker is placed on an electronic balance capable of recording mass data in real time, the mass change of the device and the beaker within 30-240 minutes is tested under the irradiation of a xenon lamp light source with the light intensity of 1-10kW/m2, and a mass change curve is drawn.

The vaporization efficiency eta of the photothermal conversion layer is calculated by the formulas (1), (2), (3) and (4)

m＝m_{Light (es)}-m_Darkness (2)

H_LV＝1.91846×10⁶[T₁/(T₁-33.91)]² (3)

Q＝c(T₁-T₀) (4)

Wherein m is the net evaporation rate of water kg/m²h，m_{Light (es)}Is the evaporation rate of water kg/m under the condition of illumination²h，m_DarknessThe evaporation rate of water is kg/m under the condition of no illumination²h；H_LVIs the latent heat of vaporization J/kg of water; t is₁The evaporation temperature of water; t is₀The initial temperature of water; c is the specific heat J/kgK of water; q is the heat J absorbed by the evaporation of water; e_inIs the energy kJ/m of the incident light input²h。

And (3) testing temperature change: the solar steam generating device is placed in a 300-plus-1000 mL water-containing beaker, the beaker is placed on an electronic balance capable of recording mass data in real time, and an infrared thermal imager is used for detecting the temperature change of the photo-thermal conversion layer before and after irradiation under the irradiation of a xenon lamp with the light intensity of 1-10kW/m 2.

And (3) blending, filtering and vacuum drying three reduced graphene oxide samples (rGO-50/200/400) with different reduction degrees and 100mg of foam nickel base to obtain the foam nickel base reduced graphene oxide photothermal conversion device. (1) The reduced graphene oxide source is connected with the foam nickel framework through weak van der waals force before the reduced graphene oxide source is reduced, and can fall off and transfer under the action of external force; (2) the driving force of the transfer of the reduced graphene oxide, namely the negative pressure of the reduced pressure filtration promotes the reduced graphene oxide on the back side to fall off and be attracted to the front side of the photothermal conversion layer; (3) the transfer channel of the reduced graphene oxide, namely the micron-sized hole structure between the foamed nickel frameworks provides a channel for transferring the reduced graphene oxide to the front surface of the photothermal conversion layer. The three factors are important in the formation process of the two-sided morphology of the foam nickel-based reduction-oxidation graphene photothermal conversion layer. Under the assistance of the heat insulation layer and the water conveying pipeline, the light absorption film is in indirect contact with the lower water body through the water conveying pipeline, so that the problem that the light-heat conversion layer is likely to sink or even decompose after being soaked for a long time is solved. The reduced graphene oxide has the advantages that the distance between molecular layers is shortened due to the removal of a large number of oxygen-containing groups, stronger intermolecular force is formed, and meanwhile, the surface hydrophilicity is greatly reduced, so that the reduced graphene oxide is agglomerated and settled.

In the process of pressure reduction and suction filtration, the reduced graphene oxide is extruded by a pair of acting forces in opposite directions to form a reduced graphene oxide shell, namely a suction force from top to bottom and a supporting force from bottom to top respectively. On a foam nickel matrix, under the action of reduced pressure suction filtration, the reduced graphene oxide gradually deposits downwards along with the reduction of liquid to form a loose porous structure. Under the action of strong suction force, the reduced graphene oxide is still tightly attached to the foam nickel framework. This indicates that the separation and transfer of reduced graphene oxide occurs between the layers of reduced graphene oxide rather than between the reduced graphene oxide and the foamed nickel skeleton.

In the photothermal conversion element of the present invention, since the photothermal conversion layer and the lower water body are separated by the heat insulating layer, heat loss caused by heat transfer from the photothermal conversion layer to the water body is effectively suppressed in the photothermal conversion process. Meanwhile, sufficient moisture is continuously supplied to the photo-thermal conversion layer through the water conveying pipeline under the action of capillary force, so that the continuous generation of solar steam is realized. Under the irradiation of sunlight intensity, the photothermal conversion layer is rapidly heated from 18.1 ℃ to 33.5 ℃ within one minute, and is stabilized at 38 ℃ after 40 minutes. After the heat insulation layer is irradiated for 40 minutes, the temperature is only raised to 25.5 ℃ from 18.1 ℃, and the temperature is basically maintained within the room temperature. The irradiation time was extended to 90 minutes and the temperature of the photothermal conversion layer and the thermal insulation layer were still stabilized at 39.5 ℃ and 25.5 ℃ respectively. On the other hand, in the irradiation time of 90 minutes, due to the blocking effect of the photothermal conversion layer on light and the inhibiting effect of the heat insulation layer on heat conduction, the lower water body is always kept within the room temperature, and the heat loss caused by the heat dissipation to the environment through the water body is greatly reduced.

Compared with a steam generating device with a photothermal conversion film directly floating on a water body, the high-efficiency solar steam generating device with the heat insulating material and the micro water delivery device has the advantages that the photothermal conversion layer prepared by synthesis can limit sunlight on the surface of the film, block radiation of the sunlight to the lower water body, reduce energy loss caused by scattering of the water body to the environment, improve the light energy utilization rate and improve the photothermal conversion performance. The thermal insulation layer and the water conveying pipeline adopted by the invention can separate the photo-thermal conversion layer from the water body, block the heat loss from the high-temperature film to the low-temperature water body, further reduce the energy loss and improve the light energy utilization rate, thereby further improving the photo-thermal conversion performance. The heat insulation material inhibits the conduction of heat from the light absorption film to the lower water body, and the heat loss is minimized; meanwhile, under the action of capillary force, the lower water body is indirectly connected with the light-heat conversion layer through the water delivery device and continuously supplies water for the light-heat conversion process. Under the cooperative assistance of the heat insulating material and the micro water delivery device, the steam efficiency of the whole photo-thermal conversion device is far higher than that of a film which purely floats on the water body. In addition, by preparing the reduced graphene oxide with different reduction degrees, the influence of the reduction degree on the photo-thermal conversion efficiency is deeply researched, and the experimental result shows that the photo-thermal conversion performance of the foam nickel-based reduced graphene oxide is gradually enhanced (up to 92.2% under the intensity of one sun) along with the improvement of the reduction degree. The solar steam generation device provides important experimental data and technical support for further research and application in the field of photothermal conversion, such as the fields of distillation purification, seawater desalination, sewage treatment and the like.

The reduced graphene oxide coating 21 on the upper surface of the foam nickel substrate is a porous coating, and the design method of the pore diameter and the porosity is as follows:

and (3) performing mathematical modeling on the working medium transportation process of the foam nickel matrix and the photothermal conversion layer by using a continuity equation, Darcy's law considering the gravity effect and an energy equation:

where φ is the porosity of the nickel foam, ρ is the density of the fluid, and v is the apparent velocity of the fluid.

In the formula, q_VIs the volume flow, k is the permeability of the foamed nickel, μ is the dynamic viscosity of the fluid; a is the cross-sectional area of the reduced graphene oxide coating 21, the thickness of the L photothermal conversion layer, pv is the vacuum degree of decompression and suction filtration, and pe is atmospheric pressure.

Wherein (ρ c)_m＝(1-φ)(ρc)_s+φ(ρc_p)_f；λ_m＝(1-φ)λ_s+φλ_f；q”_m＝(1-φ)q”_s+φq”_f(ii) a In the formula, subscripts s and f represent a solid phase of the photothermal conversion layer and a liquid phase inside the photothermal conversion layer, respectively; c is the specific heat of the solid; c. C_pIs the constant pressure specific heat of the fluid; lambda is the heat conductivity coefficient of the photo-thermal conversion layer; q "is the heat per unit volume generated by the heat source in the light-to-heat conversion layer.

Applying a fractal theory to establish an expression of the porosity and permeability of the foamed nickel:

wherein D is foam nickel pore distribution fractal dimension, D_TThe fractal dimension of the porosity tortuosity of the nickel foam, Q, is the total flow through the section a of the reduced graphene oxide coating 21.

Obtaining the average pore size corresponding to the foam nickel matrix and the photothermal conversion layer according to the obtained parameter expression as follows: ln (p/p)₀)＝-(2γV_m/rRT)cosθ

In the formula, p₀The saturated vapor pressure when the surface of the working medium on the surface of the photothermal conversion layer is a plane, p is the pressure of the liquid in the pores of the photothermal conversion layer, V_mThe molar volume of the corresponding phase, gamma is the surface tension of the corresponding phase in each zone, R is a gas constant, T is an absolute temperature, and theta is a contact angle between the liquid working medium and the pore wall of the photothermal conversion layer; the corresponding phase refers to the condition of the working medium in the photothermal conversion layer during actual work, the working medium on the surface of the photothermal conversion layer is a vapor phase, and the working medium in the pores of the photothermal conversion layer is a liquid phase.

r is the aperture of the photothermal conversion layer, and the aperture and porosity parameters of the photothermal conversion layer have important influence on the steam generation rate. The smaller the pore diameter is, the larger the saturated vapor pressure on the surface of the photothermal conversion layer is, so that the steam is not beneficial to overflowing from the pores on the surface of the photothermal conversion layer; the larger the pore diameter, the smaller the photothermal absorption area of the photothermal conversion layer surface, resulting in a decrease in photothermal conversion efficiency. Therefore, the aperture of the photothermal conversion layer needs to be calculated to ensure the most effective evaporation rate.

Preferably, the device further comprises a solar auxiliary heating device, the auxiliary heating device comprises an evaporation end and a condensation end, the evaporation end is a solar heat collecting component, the condensation end is arranged in the water tank, and the water body in the water tank is preheated through heat release of the condensation end, so that the seawater desalination efficiency is further improved.

As shown in fig. 4, the solar auxiliary heating device is also a heat collecting device, and includes a heat collecting tube box 8, an upper tube 2 and a heat releasing tube group 1, where the heat releasing tube group 1 includes a left heat releasing tube group 11 and a right heat releasing tube group 12, the left heat releasing tube group 11 is communicated with the upper tube 2 and the heat collecting tube box 8, and the right heat releasing tube group 12 is communicated with the upper tube 2 and the heat collecting tube box 8, so that the heat collecting tube box 8, the upper tube 2 and the heat releasing tube group 1 form a closed circulation of heating fluid, the heat collecting tube box 8 is filled with phase-change fluid, each heat releasing tube group 1 includes a plurality of heat releasing tubes 7 in an arc shape, ends of adjacent heat releasing tubes 7 are communicated, so that the plurality of heat releasing tubes 7 form a; the heat collecting tube box comprises a first tube opening 10 and a second tube opening 13, the first tube opening 10 is connected with an inlet of the left heat-releasing tube group 11, the second tube opening 13 is connected with an inlet of the right heat-releasing tube group 12, an outlet of the left heat-releasing tube group 11 is connected with the upper tube 2, and an outlet of the right heat-releasing tube group 12 is connected with the upper tube 2; the first nozzle 10 and the second nozzle 13 are disposed at one side of the heat collecting tube box 8. Preferably, the left and right heat-releasing

tube groups

11 and 12 are symmetrical along the middle of the heat collecting tube box.

Preferably, the upper pipes 2 and the heat-releasing pipe group 1 are arranged in a water tank 9, and a fluid is arranged in the water tank 9, wherein the fluid is seawater.

Preferably, the upper tube 2 and the heat collecting tube box 8 extend in a horizontal direction.

Preferably, a plurality of heat-releasing tube blocks 1 are provided to extend in a horizontal direction along the upper tubes 2 and the header tank 8, and the heat-releasing tube blocks 1 are connected in parallel.

Preferably, return pipes 14, 15 are provided between the upper pipe 2 and the heat collecting chamber 8. Preferably, the return pipes 14, 15 are provided at both ends of the heat collecting tube box 8. As shown at both ends in the direction perpendicular to the plane of the paper in fig. 4. The upper and lower ends of fig. 7.

The heat collecting tube box 8 is filled with phase-change fluid, preferably vapor-liquid phase-change fluid. The fluid heats the evaporation at heat collecting tube case 8, flows to upper tube 2 along heat release tube bank, and the fluid can produce the volume expansion after being heated to form steam, and the volume of steam is greater than water far away, and the steam that consequently forms can carry out the flow of quick impact formula in the coil pipe. Because of volume expansion and steam flow, the free end of the heat-radiating pipe can be induced to vibrate, the vibration is transmitted to the heat-exchanging fluid in the water tank 9 by the free end of the heat-exchanging pipe in the vibrating process, and the fluid can also generate disturbance with each other, so that the surrounding heat-exchanging fluid forms disturbance flow, a boundary layer is damaged, and the purpose of enhancing heat transfer is realized. The fluid is condensed and released heat on the left upper pipe and the right upper pipe and then flows back to the heat collecting pipe box through the return pipe.

According to the invention, the prior art is improved, and the upper pipe and the heat release pipe groups are respectively arranged into two groups distributed on the left side and the right side, so that the heat release pipe groups distributed on the left side and the right side can perform vibration heat exchange descaling, the heat exchange vibration area is enlarged, the vibration is more uniform, the heat exchange effect is more uniform, the heat exchange area is increased, and the heat exchange and descaling effects, especially the descaling effect in seawater, are enhanced.

According to the invention, the left and right pipe groups are connected with the same upper pipe 2, and compared with the two upper pipes designed in the prior art, the pressure and flow of the left and right pipe groups can be further balanced, and uniform heat exchange is ensured. This application is to above-mentioned structure further improvement, reinforcing scale removal and heat transfer effect.

In the operation of the solar heat collector, although the structure has the elastic vibration descaling effect, the descaling effect needs to be further improved after long-term operation.

It has been found in research and practice that a sustained and stable heat collection results in a stable fluid formation of the internal heat collecting means, i.e. no fluid flow or little fluid flow, or a stable flow, resulting in a greatly reduced vibration performance of the heat emitting tube bank 1, thereby affecting the efficiency of descaling and heating of the tube bank 1. For example, continuous heat collection in the day, or continuous no heat collection in the night, results in reduced descaling effect, and continuous heat collection in the day or electric heating descaling in the night is adopted in the prior application, which greatly improves the heat collection effect in the day. However, the above structure requires a separate electric heating device and complicated design of the assembly associated with the electric heating, resulting in a complicated structure, and thus the heat collecting device needs to be improved as follows.

In the prior application of the inventor, a periodic heating mode is provided, and the vibration of the coil is continuously promoted by the periodic heating mode, so that the heating efficiency and the descaling effect are improved. However, adjusting the vibration of the tube bundle with a fixed periodic variation can lead to hysteresis and too long or too short a period. Therefore, the invention improves the previous application and intelligently controls the vibration, so that the fluid in the device can realize frequent vibration, and a good descaling effect is realized.

Aiming at the defects in the technology researched in the prior art, the invention provides a novel descaling heat collector capable of intelligently controlling vibration. This heat collector can realize fine scale removal effect.

The solar heat collector comprises a descaling stage, and the heat collector operates in the following mode in the descaling stage:

self-regulation vibration based on pressure

Preferably, the heat collecting device is internally provided with a pressure detecting element for detecting the pressure inside the heat collecting device, the controller extracts pressure data according to a time sequence, the pressure data of adjacent time periods are compared to obtain the pressure difference or the accumulation of the pressure difference change, and when the pressure data of adjacent time periods is lower than a threshold value, the controller controls whether the heat collecting tube box collects heat according to the detected pressure difference or the accumulation of the pressure difference change.

Through the pressure difference of the front time period and the rear time period or the accumulated pressure difference detected by the pressure sensing element, the evaporation of the fluid inside can be judged to be basically saturated through the pressure difference, the volume of the fluid inside is basically not changed greatly, the fluid inside is relatively stable under the condition, the vibration of the tube bundle at the moment is poor, and therefore adjustment is needed, the tube bundle vibrates, and heat collection is stopped. So that the fluid undergoes volume reduction to thereby realize vibration. When the pressure difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and heat collection is needed to ensure that the fluid is evaporated and expanded again, so that heat collection needs to be started.

The stable state of the fluid is judged according to the pressure difference or the accumulation of the pressure difference change, so that the result is more accurate, and the problem of error increase caused by aging due to the running time problem is solved.

Preferably, if the pressure of the previous period is P1 and the pressure of the adjacent following period is P2, if P1< P2, the controller controls to stop heat collection to the heat collecting tube box; if P1> P2, the controller controls the heat collection of the heat collection tube box when the threshold value is lower.

And determining whether the current heat collecting tube box is in a heat collecting state or a non-heat collecting state through sequential pressure judgment, thereby determining the operation state of the heat collecting tube box according to different conditions.

Preferably, if the pressure of the previous period is P1, the pressure of the adjacent following period is P2, and if P1 is P2, heat collection is judged according to the following:

if the P1 is larger than the pressure of the first data, the controller controls the heat collecting tube box to stop collecting heat; wherein the first data is greater than the pressure of the phase change fluid after the phase change; preferably the first data is a pressure at which the phase change fluid is substantially phase-changed;

and if the pressure P1 is less than or equal to the pressure of the second data, the controller controls the heat collecting tube box to continue collecting heat, wherein the pressure of the second data is less than or equal to the pressure at which the phase-change fluid does not change phase.

The first data is pressure data of a sufficient heat collection state, and the second data is pressure data of no heat collection or the beginning of heat collection. Through the judgment of the pressure, whether the current heat collecting pipe box is in a heat collecting state or a non-heat collecting state is also determined, so that the operation state of the heat collecting pipe box is determined according to different conditions.

Preferably, the pressure sensing element is disposed within the heat collecting channel 8.

Preferably, the pressure sensing element is disposed at the free end. Through setting up at the free end, can perceive the pressure variation of free end to realize better control and regulation.

AsPreferably, the number of the pressure sensing elements is n, and the pressure P in the current time period is calculated in sequence_iPressure Q of the preceding period_i-1Difference D of_i＝P_i-Q_i-1And for n pressure differences D_iPerforming arithmetic cumulative summation

And when the value of Y is lower than a set threshold value, the controller controls the heat collecting pipe box to stop heat collection or continue heat collection.

Preferably, when Y is greater than 0, the controller controls the heat collecting pipe box to stop collecting heat if Y is lower than a threshold value; if Y is less than 0, the threshold value is lower, and the controller controls the heat collection tube box to collect heat.

Preferably, if Y is 0, heat collection is judged according to the following:

if P is_iThe arithmetic mean of the first data is greater than the pressure of the first data, the controller controls the heat collecting tube box to stop collecting heat; wherein the first data is greater than the pressure of the phase change fluid after the phase change; preferably the pressure at which the phase change fluid substantially changes phase;

if P is_iThe arithmetic mean of the first data and the second data is less than the pressure of the second data, and the controller controls the heat collecting tube box to continuously collect heat, wherein the second data is less than or equal to the pressure of the phase-change fluid without phase change.

Preferably, the period of time for measuring the pressure is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.

Preferably, the threshold is 100-1000 pa, preferably 500 pa.

Preferably, the pressure value may be an average pressure value over a period of the time period. Or may be a pressure at a certain time within a time period. For example, preferably both are pressures at the end of the time period.

Independently adjusting vibration based on temperature

Preferably, a temperature detection element is arranged in the heat collection device and used for detecting the temperature in the heat collection device, the temperature detection element is in data connection with the controller, the controller extracts temperature data according to a time sequence, the temperature difference or the accumulation of temperature difference changes is obtained through comparison of the temperature data of adjacent time periods, and when the temperature difference or the accumulation of temperature difference changes is lower than a threshold value, the controller controls the heat collection tube box to stop heat collection or continue heat collection.

Through the temperature difference between the time before and after or the accumulated temperature difference detected by the temperature sensing element, the evaporation of the internal fluid can be judged to be basically saturated through the temperature difference, and the volume of the internal fluid is basically not changed greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the temperature difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and heat collection is needed to ensure that the fluid is evaporated and expanded again, so that the heat collection tube box needs to be started to collect heat.

The stable state of the fluid is judged according to the temperature difference or the accumulation of the temperature difference change, so that the result is more accurate, and the problem of error increase caused by aging due to the problem of operation time is solved.

Preferably, if the temperature of the previous period is T1 and the temperature of the adjacent following period is T2, if T1< T2, the controller controls the heat collecting tube box to stop collecting heat below a threshold value; if T1> T2, the controller controls the heat collecting tube box to collect heat when the threshold value is lower than the threshold value.

And determining whether the current heat collecting tube box is in a heat collecting state or a non-heat collecting state through the sequential temperature judgment, thereby determining the operation state of the heat collecting tube box according to different conditions.

Preferably, if the temperature of the previous period is T1, the temperature of the adjacent following period is T2, and if T1 is T2, heat collection is judged according to the following:

if the T1 is higher than the temperature of the first data, the controller controls the heat collecting tube box to stop collecting heat; wherein the first data is greater than the temperature of the phase change fluid after the phase change; preferably the first data is a temperature at which the phase change fluid substantially changes phase;

if the temperature T1 is less than or equal to the temperature of the second data, the controller controls the heat collecting tube box to continue collecting heat, wherein the second data is less than or equal to the temperature at which the phase change fluid does not change phase.

The first data is temperature data of a sufficient heat collection state, and the second data is temperature data of no heat collection or the beginning of heat collection. Through the judgment of the temperature, whether the current heat collecting pipe box is in a heat collecting state or a non-heat collecting state is also determined, so that the operation state of the heat collecting pipe box is determined according to different conditions.

Preferably, the number of the temperature sensing elements is n, and the temperature T in the current time period is calculated in sequence_iTemperature Q of the preceding time period_i-1Difference D of_i＝T_i-Q_i-1And for n temperature differences D_iPerforming arithmetic cumulative summation

Preferably, if Y is 0, heat collection is judged according to the following:

if T is_iIs greater than the temperature of the first data,the controller controls the heat collecting pipe box to stop collecting heat; wherein the first data is greater than the temperature of the phase change fluid after the phase change; preferably the temperature at which the phase change fluid substantially changes phase;

if T is_iThe arithmetic mean of the first data and the second data is less than the temperature of the second data, and the controller controls the heat collecting tube box to continuously collect heat, wherein the second data is less than or equal to the temperature at which the phase change fluid does not change phase.

Preferably, the period of time for measuring the temperature is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.

Preferably, the threshold is 1-10 degrees Celsius, preferably 4 degrees Celsius.

Preferably, the temperature sensing element is disposed within the heat collecting channel 8.

Preferably, the temperature sensing element is disposed at the free end. Through setting up at the free end, can perceive the temperature variation of free end to realize better control and regulation.

Thirdly, automatically adjusting vibration based on liquid level

Preferably, a liquid level detection element is arranged in the heat collection tube box and used for detecting the liquid level of fluid in the lower tube box, the liquid level detection element is in data connection with the controller, the controller obtains the liquid level difference or the accumulation of the liquid level difference change through comparison of liquid level data of adjacent time periods according to the time sequence liquid level data, and when the liquid level difference or the liquid level difference change is lower than a threshold value, the controller controls the heat collection tube box to stop heat collection or continue heat collection.

Through the liquid level difference of the front time and the back time or the accumulated liquid level difference detected by the liquid level sensing element, the evaporation of the internal fluid can be judged to be basically saturated through the liquid level difference, and the volume of the internal fluid is basically not changed greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the liquid level difference rises to a certain degree, the internal fluid starts to enter a stable state again, and heat collection is needed to ensure that the fluid is evaporated and expanded again, so that the heat collection tube box needs to be started to collect heat.

The stable state of the fluid is judged according to the liquid level difference or the accumulation of the change of the liquid level difference, so that the result is more accurate, and the problem of error increase caused by aging due to the problem of operation time is solved.

Preferably, if the liquid level of the previous period is L1 and the liquid level of the adjacent following period is L2, if L1> L2, the controller controls the heat collecting tube box to stop collecting heat below a threshold value; if the L1< L2, the threshold value is lower, the controller controls the heat collecting tube box to collect heat.

And determining whether the current heat collecting tube box is in a heat collecting state or a non-heat collecting state through the sequential liquid level judgment, thereby determining the operation state of the heat collecting tube box according to different conditions.

Preferably, if the liquid level of the previous period is L1, and the liquid level of the adjacent subsequent period is L2, if L1 is L2, heat collection is judged according to the following:

if the L1 is less than the liquid level of the first data or the L1 is 0, the controller controls the heat collecting tube box to stop collecting heat; wherein the first data is greater than the liquid level of the phase-change fluid after the phase change; preferably the first data is a level at which the phase change fluid is substantially phase changed;

and if the L1 is greater than or equal to the liquid level of the second data, the controller controls the heat collecting tube box to continuously collect heat, wherein the second data is less than or equal to the liquid level at which the phase change fluid does not have phase change.

The first data is liquid level data in a full heat collection state, including liquid level of dry-out, and the second data is liquid level data without heat collection or just beginning heat collection. Through the judgment of the liquid level, whether the current heat collecting tube box is in a heat collecting state or a non-heat collecting state is also determined, so that the operation state of the heat collecting tube box is determined according to different conditions.

Preferably, the number of the liquid level sensing elements is n, and the liquid level L in the current time period is calculated in sequence_iAnd the liquid level Q of the previous time period_i-1Difference D of_i＝L_i-Q_i-1And for n liquid level differences D_iPerforming arithmetic cumulative summation

Preferably, if Y is 0, heat collection is judged according to the following:

if L is_iThe arithmetic mean of the first data is less than the liquid level of the first data or 0, and the controller controls the heat collecting tube box to stop collecting heat; wherein the first data is greater than the liquid level of the phase-change fluid after the phase change; preferably a level at which the phase change fluid is substantially phase-changed;

if L is_iThe arithmetic mean of the first data and the second data is larger than the liquid level of the second data, and the controller controls the heat collecting tube box to continuously collect heat, wherein the second data is smaller than or equal to the liquid level at which the phase change fluid does not change the phase.

Preferably, the period of time for which the measurement is also made is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.

Preferably, the threshold is 1-10 mm, preferably 4 mm.

Preferably, the water level value may be an average water level value over a period of the time period. Or the water position at a certain moment in time. Such as preferably both water levels at the end of the time period.

Fourthly, automatically adjusting vibration based on speed

Preferably, a speed detection element is arranged in the free end of the tube bundle and used for detecting the flow speed of fluid in the free end of the tube bundle, the speed detection element is in data connection with the controller, the controller extracts speed data according to a time sequence, the speed difference or the accumulation of the speed difference change is obtained through the comparison of the speed data of adjacent time periods, and when the speed difference or the accumulation of the speed difference is lower than a threshold value, the controller controls the heat collection tube box to stop heat collection or continue heat collection.

Through the time speed difference before and after the speed sensing element detects or the accumulated speed difference, the evaporation of the internal fluid can be judged to be basically saturated through the speed difference, and the volume of the internal fluid is basically not changed greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the speed difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and heat collection is needed to ensure that the fluid is evaporated and expanded again, so that the heat collection tube box needs to be started to collect heat.

The stable state of the fluid is judged according to the speed difference or the accumulation of the speed difference change, so that the result is more accurate, and the problem of error increase caused by aging due to the running time problem is solved.

Preferably, if the speed of the previous period is V1 and the speed of the adjacent following period is V2, if V1 < V2, the controller controls the heat collecting tube box to stop collecting heat below the threshold; if V1 is greater than V2, the threshold value is lower, and the controller controls the heat collecting tube box to collect heat.

And determining whether the current heat collecting tube box is in a heat collecting state or a non-heat collecting state through the sequential speed judgment, thereby determining the operation state of the heat collecting tube box according to different conditions.

Preferably, if the velocity of the preceding time period is V1, and the velocity of the adjacent succeeding time period is V2, if V1 is V2, heat collection is judged according to the following conditions:

if the V1 is greater than the speed of the first data, the controller controls the heat collecting tube box to stop collecting heat; wherein the first data is greater than the speed of the phase change fluid after the phase change; preferably the first data is the speed at which the phase change fluid is substantially phase changed;

if the V1 is less than or equal to the speed of the second data, the controller controls the heat collecting tube box to continue collecting heat, wherein the second data is less than or equal to the speed at which the phase-change fluid does not change phase.

The first data is speed data of a sufficient heat collection state, and the second data is speed data of no heat collection or the beginning of heat collection. Through the judgment of the speed, whether the current heat collecting pipe box is in a heat collecting state or a non-heat collecting state is also determined, so that the operation state of the heat collecting pipe box is determined according to different conditions.

Preferably, the number of the speed sensing elements is n, and the speed V of the current time period is calculated in sequence_iAnd the previous time speed Q_i-1Difference D of_i＝V_i-Q_i-1And for n speed differences D_iPerforming arithmetic cumulative summation

Preferably, if Y is 0, heat collection is judged according to the following:

if V_iThe controller controls the heat collecting channel to stop collecting heat at a speed at which the arithmetic mean of the first data is greater than the first data; wherein the first data is greater than the speed of the phase change fluid after the phase change; preferably the rate at which the phase change fluid changes phase substantially;

if V_iThe arithmetic mean of the first data and the second data is less than the speed of the second data, and the controller controls the heat collecting tube box to continue collecting heat, wherein the second data is less than or equal to the speed of the phase-change fluid without phase change.

Preferably, the period of time for measuring the speed is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.

Preferably, the threshold is 1-3 m/s, preferably 2 m/s.

Preferably, the speed value may be an average pressure value over a period of the time period. Or may be a speed at a certain time within the time period. For example, preferably both are speeds at the end of the time period.

Preferably, the heat exchanger comprises a descaling process, and the heat exchange is carried out in the descaling process in the manner described above.

Preferably, the heat collecting tube box is heated or not heated by rotating the reflector. When heat collection is required (period front time), the reflecting surface of the reflector faces the sun, and when heat collection is not required (period rear time), the reflecting surface of the reflector does not face the sun. This can be achieved by means of a rotating mirror of a conventional solar tracking system, which need not be described in detail here.

Preferably, another embodiment may be adopted, in which the operation of whether to collect heat or not to collect heat is performed on the heat collecting tube box in a manner of whether the heat collecting tube box is located at the focal point of the reflector. When heat collection is required (period front time), the heat collection tube box is positioned at the focus of the reflector, and when heat collection is not required (period rear time), the heat collection tube box is not positioned at the focus of the reflector.

As shown in fig. 4, the reflector 16 is divided into two parts along the middle, a first part 161 and a second part 162, and a first part 161 and a second part 162, as shown in fig. 5. The support member 17 is a support column disposed at a lower portion of the heat collecting tube box 8, and the pneumatic

telescopic rods

171 and 172 are extended from the support column to be connected to the first and

second portions

161 and 162, respectively. For driving the first and second parts apart or together. When the first part and the second part are combined together, the reflector 16 forms a complete reflector, and the heat collecting tube box is located at the focal position of the reflector 16 for collecting heat from the heat collecting tube box. When the first part and the second part are separated, the heat collecting pipe box is not positioned at the focus of the first part and the second part, and heat is not collected to the heat collecting pipe box.

Preferably, the pneumatic telescopic rod is connected with the driver, the driver drives the pneumatic telescopic rod to extend and retract, and the position of the focal point of the reflector is changed by the extension and retraction of the pneumatic telescopic rod.

The air powered telescopic pole is connected to the support 17 in a pivoting manner.

As a modified example, as shown in fig. 5-3 and 5-4. The heat collecting device comprises a right pneumatic device 26 and a left pneumatic device 27,

telescopic rods

36 and 35 are arranged at the upper parts of the right pneumatic device 26 and the left pneumatic device 27 and are connected to the lower parts of a second part 162 and a first part 161 in a pivoting mode, and an air compressor and an electromagnetic steering valve are adopted to drive the right pneumatic device 26 and the left pneumatic device 27 to ascend and descend respectively.

Preferably, the device further comprises a right support bar 28 and a left support bar 29, the right support bar 28 and the left support bar 29 comprising a first part and a second part, the first part being located at the lower part, the lower end of the first part being pivotally connected to the support bar 17, the second part being a telescopic bar, the upper end of the telescopic bar being pivotally connected to the first part 161 and the second part 162. The telescoping rod may telescope within the first member. The right and left support bars 28 and 29 serve to support the mirror so that the mirror is maintained at a lower corresponding position. For example, when the first and second portions of the reflector are combined, the first and second portions are supported by the right and left

support rods

28 and 29 to be maintained at corresponding positions, so that the heat collecting tube box 8 is located at the focal point of the reflector.

Preferably, the first member is a rod having an opening in the middle thereof, such that the telescopic rod is able to telescope within the first member.

Preferably, the right support rod 28 and the left support rod 29 are also pneumatically driven, and a pneumatic device is separately provided, and the first component is a pneumatic device, and the telescopic rod is driven to extend and retract through an air compressor and an electromagnetic steering valve. The specific structure is similar to the right pneumatic device 26 and the left pneumatic device 27.

Fig. 8 shows a specific structure of the pneumatic device. As shown in fig. 8, the pneumatic device is a cylinder structure, and the pneumatic device includes an intake valve 30, a cylinder 31, a piston cavity 32, an exhaust valve 33, a magnetic ring 34, a piston seal 37, a guide ring 38, a support rod 28 and a piston 39. The cylinder 31 is communicated with an air compressor through an air inlet 30, the normal pressure in the cylinder is kept at 2MPa, and the air pressure in the cylinder 31 is provided by the air compressor. When the piston 39 moves upwards, the magnetic ring 34 mounted on the piston 39 and the upper inductor on the outer wall of the cylinder generate electromagnetic induction, when the magnetic ring 34 and the upper inductor coincide, the air inlet valve 30 is closed, the piston 39 stops moving, and therefore the supporting rod connected with the piston keeps a certain position still. When the piston 39 moves downward, the exhaust valve 33 becomes an intake valve and the intake valve 30 becomes an exhaust valve through the electromagnetic directional valve, the compressed air pushes the piston 39 to move downward, and when the magnetic ring 34 and the lower electromagnetic inductor are superposed, the intake valve is closed and the piston is still.

When the reflector is to be lifted to stop the device from collecting heat, the controller controls the piston to move upwards.

When the reflector is lowered to start heat collection, the controller controls the piston to move downwards.

Preferably, the heat release pipes of the left heat release pipe group are distributed around the axis of the left upper pipe, and the heat release pipes of the right heat release pipe group are distributed around the axis of the right upper pipe. The left upper pipe and the right upper pipe are arranged as circle centers, so that the distribution of the heat release pipes can be better ensured, and the vibration and the heating are uniform.

Preferably, the left heat-releasing tube group and the right heat-releasing tube group are both plural.

Preferably, the left heat-releasing tube group and the right heat-releasing tube group are mirror-symmetrical along a plane on which a vertical axis of the heat collecting tube box is located. Through such setting, can make the heat release pipe distribution of heat transfer more reasonable even, improve the heat transfer effect.

Preferably, the heat collecting tube box 8 has a flat tube structure. The heat absorption area is increased by arranging the flat tube structure. So that the heat collecting tube box 8 can be ensured to be positioned at the focal point of the reflector even if the installation position is a little remote.

Preferably, the left heat-releasing tube group 11 and the right heat-releasing tube group 12 are staggered in the horizontal extending direction. Through the staggered distribution, can make to vibrate on different length and release heat and scale removal for the vibration is more even, strengthens heat transfer and scale removal effect.

Preferably, a reflecting mirror 16 is provided at a lower portion of the heat collecting device, the heat collecting tube box is located at a focal position of the reflecting mirror 16, and the left and right heat releasing tube groups are located in the fluid passage. Thereby forming a solar energy collection system.

Preferably, a support 17 is included, and the support 17 supports the heat collecting device.

Preferably, a box body 9 is included, as shown in fig. 5, and the heat collecting tube box 8 is located at the lower end of the box body 9, as shown in fig. 5. The upper tube 2, the left heat-releasing tube group 11 and the right heat-releasing tube group 12 are disposed in the fluid passage, and heat the fluid in the fluid passage by releasing heat.

Preferably, the flow direction of the fluid is the same as the direction in which the upper tube 2 and the heat collecting tube box 8 extend. Through such arrangement, the fluid scours the heat release pipe set when flowing, especially the free end of the heat release pipe set, so that the free end vibrates, heat transfer is enhanced, and the descaling effect is achieved.

Preferably, the heat release tube group 1 is provided in plural (for example, on the same side (left side or right side)) along the flow direction of the fluid in the fluid passage, and the tube diameter of the heat release tube group 1 (for example, on the same side (left side or right side)) along the flow direction of the fluid in the fluid passage becomes larger.

Along the flowing direction of the fluid, the temperature of the fluid is continuously increased, so that the heat exchange temperature difference is continuously reduced, and the heat exchange capacity is increased more and more. Through the pipe diameter grow of heat release nest of tubes, can guarantee that more steam passes through upper portion and gets into heat release nest of tubes, guarantee along fluid flow direction because the steam volume is big and the vibration is effectual to make whole heat transfer even. The distribution of steam in all heat release pipe groups is even, further strengthens heat transfer effect for the whole vibration effect is even, and the heat transfer effect increases, further improves heat transfer effect and scale removal effect.

Preferably, the heat release pipe diameter of the heat release pipe group (for example, the same side (left side or right side)) is increased along the flowing direction of the fluid in the fluid passage.

Through so setting up, avoid the fluid all to carry out the heat transfer at front, and the heat transfer of messenger increases to the rear portion as far as possible to form the heat transfer effect of similar countercurrent. Experiments show that better heat exchange effect and descaling effect can be achieved by adopting the structural design.

Preferably, the heat release pipe groups on the same side (left side or right side) are arranged in plurality along the flowing direction of the fluid in the fluid channel, and the interval between the adjacent heat release pipe groups on the same side (left side or right side) is gradually reduced from the top to the bottom. The specific effect is similar to the effect of the previous pipe diameter change.

Preferably, the spacing between the heat release pipe groups on the same side (left side or right side) along the flowing direction of the fluid in the fluid channel is increased in a decreasing amplitude. The specific effect is similar to the effect of the previous pipe diameter change.

In tests it was found that the volume, the distance of the upper tube 2 and the volume of the collection tank can have an effect on the heat exchange efficiency and the homogeneity. If the volume undersize of thermal-arrest case, lead to the steam overheated, the heat can't in time be transmitted to exothermic pipe and upper left pipe right side top tube, the volume is too big, lead to the steam condensation too fast, also can't transmit, the volume of going up 2 with the management must be suitable for with the long-pending collocation of thermal-arrest water tank, otherwise can lead to the steam condensation too fast or too slow, all can lead to the heat transfer condition to worsen, go up between 2 apart from also can lead to heat exchange efficiency too poor, the distance is too little, then exothermic pipe distributes too closely, also can influence heat exchange efficiency, go up between 2 apart from also need with thermal-arrest case apart from collocation be suitable for mutually, otherwise the distance between them can influence the volume of the liquid or the steam that hold, then can produce the influence to the vibration of free end, thereby. The volume of the upper tube 2, the distance and the volume of the heat collecting tank have a certain relation.

The invention provides an optimal size relation summarized by numerical simulation and test data of a plurality of heat pipes with different sizes. Starting from the maximum heat exchange amount in the heat exchange effect, nearly 200 forms are calculated. The dimensional relationship is as follows:

the volume of the upper pipe 2 is V1, the volume of the heat collecting box is V3, the included angle formed between the middle point of the bottom of the heat collecting water tank and the circle centers of the left upper pipe and the right upper pipe is A, and the following requirements are met:

V1/V3＝a-b*sin(A/2)²-c sin (a/2); where a, b, c are parameters, sin is a triangular sine function,

0.8490< a <0.8492, 0.1302< b <0.1304, 0.0020< c < 0.0022; preferably, a is 0.8491, b is 0.1303, and c is 0.0021.

Preferably, the included angle A formed between the midpoint of the bottom of the heat collecting water tank and the center of the upper tube 2 is 40-120 degrees (angle), preferably 80-100 degrees (angle).

Preferably, 0.72< (V1)/V3< 0.85;

preferably, the number of the heat release pipes of the heat release pipe group is 3 to 5, preferably 3 or 4.

Preferably, the radius of the heat-radiating pipe is preferably 10-40 mm; preferably 15 to 35mm, more preferably 20 to 30 mm.

Preferably, the arc between the ends of the free ends 3, 4, centered on the central axis of the left header, is 95-130 degrees, preferably 120 degrees. The same applies to the curvature of the free ends 5, 6 and the free ends 3, 4. Through the design of the preferable included angle, the vibration of the free end is optimal, and therefore the heating efficiency is optimal.

In the prior application, only by means of the fact that the distance between the center of the upper left pipe and the center of the upper right pipe is M, the pipe diameter of the upper left pipe and the radius of the upper right pipe are the same and are B, the radius of the axis of the innermost heat radiation pipe in the heat radiation pipes is N1, and the radius of the axis of the outermost heat radiation pipe is W2, the volume and the distance of the upper pipes and the volume of the heat collection box are related through an optimized relational expression for the first time, and the optimal size relation is obtained. The above relation formula of the present application is a further improvement of the relation formula of the previous application, and belongs to the original invention point of the present invention through the relation formula of the volume and the included angle.

Preferably, the tube bundle of the heat-releasing tube group 1 is an elastic tube bundle.

The heat exchange coefficient can be further improved by arranging the tube bundle of the heat release tube group 1 with an elastic tube bundle.

The number of the heat release pipe groups 1 is plural, and the plurality of the heat release pipe groups 1 are in a parallel structure.

The evaporator of the loop heat pipe is positioned at the focus of the solar reflector, sunlight is reflected and focused by the solar tracking reflector and then heats the evaporator of the loop heat pipe, sewage or seawater is filtered by the filter and then is pumped into the water tank by the water pump, the loop heat pipe releases heat to the water tank and heats the sewage or seawater in the water tank; under the action of capillary siphonage, sewage or seawater enters a hydrophobic channel at the bottom of a heat insulation layer of the photothermal conversion device, wets a foam nickel matrix, and then conveys water to a reduced graphene oxide photothermal conversion layer under the action of porous medium conveying; the photo-thermal conversion layer generates light-heat conversion under the irradiation of sunlight, and water on the upper surface of the photo-thermal conversion layer is heated and evaporated to form steam; the steam moves upwards, one part of the steam is blocked by the transparent glass cover and is adhered to the inner wall of the glass cover for natural cooling, condensed water is increased along with the continuous generation of the steam, the condensed water flows into the water collecting tank under the action of gravity, and then the condensed water is discharged into the fresh water collecting device through the drain holes uniformly distributed at the bottom of the water collecting tank; the rest steam is discharged into a condensing coil pipe positioned at the bottom of the water tank for condensation through a steam conveying pipeline above the glass cover, the heat released in the condensation process can heat the sewage, and condensed water after condensation is discharged into a fresh water collecting device.

Along with the continuous operation of solar energy, the sensor detects temperature and pressure of the loop heat pipe and other output signals to the automatic control system, the automatic control system identifies and processes the signals and then feeds the signals back to the pneumatic device, the pneumatic device adjusts the air inflation amount in the cylinder according to the feedback signals, and the gas in the cylinder pushes the piston and the connecting rod to move so as to ensure the vibration and the descaling operation of the loop heat pipe.

Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An active solar tracking heat collecting device comprises a water tank, a light-heat conversion element, wherein the upper end of the water tank is of an open structure, the light-heat conversion element floats in seawater on the upper part of the water tank, the light-heat conversion element comprises a base body formed by foaming materials, and a groove with an opening on the upper side is formed in the base body, the device further comprises a solar auxiliary heating device, the auxiliary heating device comprises an evaporation end and a condensation end, the evaporation end is a solar heat collecting component, the condensation end is arranged in the water tank, the solar auxiliary heating device is also a heat collecting device and comprises a heat collecting pipe box, an upper pipe and a heat releasing pipe group, the heat releasing pipe group comprises a left heat releasing pipe group and a right heat releasing pipe group, the left heat releasing pipe group is communicated with the upper pipe and the heat collecting pipe box, the right heat releasing pipe group is communicated with the upper pipe and the heat collecting pipe, phase-change fluid is filled in the heat collecting tube box, each heat release tube group comprises a plurality of arc-shaped heat release tubes, the end parts of the adjacent heat release tubes are communicated, the heat release tubes form a series structure, and the end parts of the heat release tubes form free ends of the heat release tubes; the heat collection tube box comprises a first tube opening and a second tube opening, the first tube opening is connected with an inlet of the left heat release tube group, the second tube opening is connected with an inlet of the right heat release tube group, an outlet of the left heat release tube group is connected with the upper tube, and an outlet of the right heat release tube group is connected with the upper tube; the first pipe orifice and the second pipe orifice are arranged on one side of the heat collecting pipe box.

2. The device as claimed in claim 1, wherein a temperature detecting element is disposed inside the evaporation end for detecting the temperature inside the heat collecting device, the temperature detecting element is in data connection with the controller, the controller extracts temperature data according to a time sequence, the temperature difference or the accumulation of the temperature difference change is obtained through the comparison of the temperature data of adjacent time periods, and when the temperature difference or the accumulation of the temperature difference change is lower than a threshold value, the controller controls the heat collecting channel to stop heat collection or continue heat collection.

3. The device as claimed in claim 2, wherein the groove is filled with a foamed nickel matrix, the lower wall surface of the matrix is provided with a capillary structure water delivery channel, the water delivery channel is communicated with the water body of the water tank and the foamed nickel matrix, the upper part of the groove is provided with a photothermal conversion coating, the photothermal conversion coating is connected with the foamed nickel matrix, and the buoyancy of the foaming material is larger than the gravity.

4. The apparatus of claim 3, wherein the reflecting mirror is divided into two parts along a middle portion, a first part and a second part, respectively, the supporting member is a supporting column disposed at a lower portion of the heat collecting chamber, and the pneumatic telescopic rods are extended from the supporting column to be connected to the first part and the second part, respectively, for driving the first part and the second part to be separated or combined; when the first part and the second part are combined together, the reflector forms a complete reflector, and the heat collection tube box is positioned at the focal position of the reflector and used for collecting heat for the heat collection tube box; when the first part and the second part are separated, the heat collecting pipe box is not positioned at the focus of the first part and the second part, and heat is not collected to the heat collecting pipe box.

5. The device as claimed in claim 4, wherein the pneumatic telescopic rod is connected with a driver, the driver drives the pneumatic telescopic rod to extend and retract, and the position of the focal point of the reflector is changed by extending and retracting the pneumatic telescopic rod, and the pneumatic telescopic rod is of a cylinder structure and comprises an air inlet valve, an air cylinder, a piston cavity, an air outlet valve, a magnetic ring, a piston seal, a guide ring, a support rod and a piston; the air cylinder is communicated with the air compressor through an air inlet hole, when the piston moves upwards, the magnetic ring arranged on the piston and the upper inductor on the outer wall of the air cylinder generate electromagnetic induction, when the positions of the magnetic ring and the upper electromagnetic inductor coincide, the air inlet valve is closed, the piston stops moving, and therefore the supporting rod connected with the piston keeps a certain position to be still; when the piston moves downwards, the exhaust valve is changed into an air inlet valve and the air inlet valve is changed into an exhaust valve, the piston is pushed to move downwards by compressed air, and when the magnetic ring and the lower electromagnetic inductor are superposed, the air inlet valve is closed and the piston is still.