Solar photovoltaic microfluidic cooling device based on electroosmosis drive

Abstract

The present invention discloses a solar photovoltaic microfluidic cooling device based on electroosmosis drive, wherein the cooling device is arranged on the back of a photovoltaic panel, and the photovoltaic panel is used for solar photovoltaic power generation; a microchannel is arranged in the cooling device, and the cooling device utilizes the electric energy obtained by photovoltaic power generation of the photovoltaic panel, and under the action of the electric energy, drives the cooling medium in the microchannel based on the electroosmosis drive principle to realize cooling of the photovoltaic panel.

Description

Technical Field

[0001] The invention belongs to the technical field of solar photovoltaic thermal management, and in particular to a solar photovoltaic micro-channel cooling device based on electroosmosis drive. Background Art

[0002] Solar photovoltaic power generation is a clean and pollution-free way of generating electricity, but the photoelectric conversion efficiency of photovoltaic modules is usually only about 20%. Many literatures point out that the efficiency of photovoltaic power generation is directly related to the temperature of photovoltaic panels. For every 1°C increase in temperature, the photoelectric conversion efficiency decreases by 0.5%. In addition, high temperature will accelerate the thermal degradation of photovoltaic cells, causing irreversible damage to their structure, thereby shortening their service life. When the upper temperature limit is reached, the aging rate of photovoltaic modules doubles for every 10°C increase in temperature. For the above reasons, it is particularly important to efficiently cool photovoltaic panels.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes a solar photovoltaic microchannel cooling device based on electroosmosis drive, which efficiently cools photovoltaic panels by generating controllable electroosmotic flow, thereby improving the photoelectric conversion efficiency and extending the life of photovoltaic components.

[0005] The object of the present invention is to achieve the following technical solution: a solar photovoltaic microchannel cooling device based on electroosmosis drive, characterized in that:

[0006] The cooling device is arranged on the back of a photovoltaic panel, and the photovoltaic panel is used for solar photovoltaic power generation;

[0007] The cooling device is provided with a microchannel,

[0008] The cooling device utilizes the electric energy obtained by photovoltaic power generation of the photovoltaic panel, and under the action of the electric energy, drives the cooling medium in the microchannel based on the electroosmotic driving principle to achieve cooling of the photovoltaic panel.

[0009] Preferably,

[0010] The cooling device is detachable.

[0011] Preferably,

[0012] The microchannel is detachable.

[0013] Preferably,

[0014] The microchannel is formed by a housing of the cooling device and a plate connected to the housing.

[0015] Preferably,

[0016] The cross-sectional area of ​​the microchannel is less than 0.0025 mm 2 .

[0017] Preferably,

[0018] A thin electrode is disposed on the inner wall of the microchannel, and the thickness of the thin electrode is determined so as not to significantly hinder the flow of the cooling medium.

[0019] Preferably,

[0020] The cooling medium of the microchannel circulates between the microchannel and a liquid storage tank outside the cooling device.

[0021] Preferably,

[0022] The driving device is connected to the photovoltaic panel via a heat-conducting structure.

[0023] Preferably,

[0024] The heat-conducting structure is a heat-conducting column.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The present invention utilizes the electric energy generated by photovoltaic panels for power generation. Based on the principle of electroosmosis drive, only very low energy consumption is required to absorb the waste heat generated by the photovoltaic panels during operation through the cooling medium, so that the operating temperature of the photovoltaic panels can be effectively controlled, thereby achieving the effect of improving the photoelectric conversion efficiency and extending its service life.

[0027] Compared with the prior art, the device of the present invention has a light structure and high photovoltaic cooling efficiency. According to numerical simulation calculations, the cooling device can cool the working temperature of the photovoltaic panel from 60.06°C to 36.47°C, with a temperature reduction of 39.28%, and the relative photoelectric conversion efficiency is increased by about 11.78%. Compared with the traditional pressure-driven water cooling method, the microchannel water cooling method based on electroosmosis drive proposed in the present invention has higher cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0029] In the attached picture:

[0030] Figure 1 is a schematic structural diagram of a solar photovoltaic micro-channel cooling device based on electroosmosis drive according to an embodiment of the present invention;

[0031] Figure 2 is a schematic structural diagram of a cooling device based on an electroosmotic driven solar photovoltaic microchannel cooling device according to an embodiment of the present invention;

[0032] Figure 3 is a schematic structural diagram of a cooling device based on an electroosmotic driven solar photovoltaic microchannel cooling device according to an embodiment of the present invention;

[0033] Figure 4 1. It is a schematic diagram of the flow channel structure of a solar photovoltaic micro-channel cooling device based on electroosmosis drive according to one embodiment of the present invention;

[0034] Figure 5 It is a temperature cloud diagram when the temperature of the photovoltaic panel reaches a steady state under different working conditions of the solar photovoltaic micro-channel cooling device driven by electroosmosis according to one embodiment of the present invention, which shows that the cooling effect of the liquid working medium driven by electroosmosis is obvious;

[0035] Figure 6 It is a schematic diagram of the steady-state average temperature of the photovoltaic panel under different working conditions of the solar photovoltaic microfluidic cooling device based on electroosmosis drive according to one embodiment of the present invention, which shows that the electroosmosis driven liquid working fluid cooling effect is obvious and is better than the traditional pressure driven liquid working fluid method;

[0036] Figure 7 is a schematic diagram of the temperature change of the working medium of the solar photovoltaic micro-channel cooling device based on electroosmosis drive according to an embodiment of the present invention, which illustrates that the temperature of the cooling medium rises significantly and the heat exchange is sufficient;

[0037] Figure 8 It is a schematic diagram of the fluid flow line diagram in the flow channel of a solar photovoltaic microchannel cooling device driven by electroosmosis according to an embodiment of the present invention, which illustrates that under the action of the cross-arranged electrodes, the working fluid has a large disturbance in the flow channel.

[0038] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0039] The following will refer to the attached Figures 1 to 8Specific embodiments of the present invention are described in more detail. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0040] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0041] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0042] like Figures 1 to 8 As shown, in one embodiment, the present invention discloses a solar photovoltaic microchannel cooling device based on electroosmosis drive, wherein:

[0043] The cooling device is arranged on the back of a photovoltaic panel, and the photovoltaic panel is used for solar photovoltaic power generation;

[0044] The cooling device is provided with a microchannel,

[0045] The cooling device utilizes the electric energy obtained by photovoltaic power generation of the photovoltaic panel, and under the action of the electric energy, drives the cooling medium in the microchannel based on the electroosmotic driving principle to achieve cooling of the photovoltaic panel.

[0046] It should be noted that the above embodiments reveal the key inventive concept of the present invention: using the electric energy generated by photovoltaic panels to generate electricity, based on the principle of electroosmotic drive, only very low energy consumption is required to absorb the waste heat generated by the photovoltaic panels during operation through the cooling medium, so that the working temperature of the photovoltaic panels can be effectively controlled, thereby achieving the effect of improving the photoelectric conversion efficiency and extending its service life. Compared with the traditional pressure-driven method, the method based on electroosmotic drive does not require an external fluid mechanical pump and has lower energy consumption. The present invention uses a portion of the electric energy generated by photovoltaic power generation as external energy for driving force, which enables the present invention to achieve a self-driven effect.

[0047] In one embodiment,

[0048] The cooling device is detachable.

[0049] In one embodiment,

[0050] The microchannel is detachable.

[0051] In one embodiment,

[0052] The microchannel is formed by a housing of the cooling device and a plate connected to the housing.

[0053] At this time, illustratively, the outer shell can be a thin plate, and the plate connected to the outer shell can be a semi-enclosed, semi-closed plate, and the two are combined to form a hollow channel as the microfluidic channel.

[0054] In one embodiment,

[0055] The outer shell of the cooling device is preferably an aluminum shell, and the outer shell includes an aluminum thin plate, and a plurality of aluminum semicircular arc plates can be installed on the aluminum thin plate.

[0056] It should be noted that the aluminum thin plate and the semicircular arc plate together form a microchannel for the electrolyte solution. Further, the aluminum semicircular arc plate may be detachable.

[0057] For the above two embodiments, no matter how the microfluidic channel is designed, various designs of the microfluidic channel can be achieved by changing the size and arrangement of each component of the microfluidic channel.

[0058] In one embodiment,

[0059] The cross-sectional area of ​​the microchannel is less than 0.0025 mm 2 .

[0060] In one embodiment,

[0061] A thin electrode is disposed on the inner wall of the microchannel, and the thickness of the thin electrode is determined so as not to significantly hinder the flow of the cooling medium.

[0062] In one embodiment,

[0063] The cooling medium of the microchannel circulates between the microchannel and a liquid storage tank outside the cooling device.

[0064] In one embodiment,

[0065] The liquid storage tank is connected with the inlet and outlet of the cooling device.

[0066] In one embodiment,

[0067] The driving device is connected to the photovoltaic panel via a heat-conducting structure.

[0068] In one embodiment,

[0069] The heat-conducting structure is a heat-conducting column.

[0070] In one embodiment, see Figure 2 ,

[0071] Within the scope of the back side of the photovoltaic panel, a single micro-channel includes a plurality of straight line segments parallel to each other;

[0072] In a range beyond the back side of the photovoltaic panel, a single microchannel includes an arc-shaped connecting segment, and the arc-shaped connecting segment is used to connect two adjacent straight line segments.

[0073] In one embodiment,

[0074] The electrodes are arranged in a staggered manner on the inner wall of the microchannel, and are used to provide a driving electric field for the electroosmotic flow of the electrolyte cooling medium under the action of electric energy.

[0075] Wherein, the electric field is perpendicular to the flow direction of the cooling medium.

[0076] In one embodiment,

[0077] The electrode arrangement is non-uniform.

[0078] In this way, disturbances of the cooling medium in the flow channel will be generated in the microchannel, destroying the formation of the heat transfer boundary layer and achieving enhanced heat exchange.

[0079] In one embodiment,

[0080] A power source is arranged above the front surface of the photovoltaic panel, and the power source collects the electric energy obtained by the photovoltaic panel through photovoltaic power generation, and provides a part of the electric energy to the thin electrode in the microchannel.

[0081] For a better understanding, Figure 1 , Figure 2 As shown, in a solar photovoltaic microchannel cooling device based on electroosmosis drive,

[0082] Photovoltaic panels 1, which convert light energy into electrical energy,

[0083] A cooling device 2 is arranged on the back of the photovoltaic panel 1, and the cooling device 2 includes:

[0084] The housing 6 is detachably connected to the back of the photovoltaic panel 1. The housing 6 is provided with a heat-conducting column 11 for heat-conducting connection to the back of the photovoltaic panel 1.

[0085] A detachable flow channel 9 is provided on the housing 6, wherein the detachable flow channel 9 has a working medium inlet 7 and a working medium outlet 8 for guiding an electrolyte solution for cooling.

[0086] A plurality of electrodes 10 are cross-arranged on the side wall of the detachable flow channel 9 to generate an electric field for electroosmosis driving via a potential difference between the electrodes 10;

[0087] The liquid storage tank 3 is connected to the working medium inlet 7 and the working medium outlet 8 respectively to circulate the electrolyte solution.

[0088] When the solid surface contacts the solution, it will be charged due to ionization. In order to achieve charge balance at the solid-liquid interface, equal amounts of opposite charges in the solution will be attracted to the vicinity of the solid wall, thereby forming a double electric layer. The double electric layer structure can be divided into a tight layer close to the solid wall and a diffusion layer under the influence of ion thermal motion. When an external power supply is applied, an electric field will be formed inside the solution. Under the action of the electric field parallel to the direction of the double electric layer on the solid wall, the ions in the double electric layer will undergo directional migration. Based on the hydration of ions and water molecules, the directional moving ions will drive the water molecules to move together, thereby generating electroosmotic flow. It can achieve efficient driving of the electrolyte solution in the microchannel. Its essence is to convert a small amount of potential energy into kinetic energy of the working fluid flow. Compared with the traditional water pump that relies on pressure to drive the working fluid, the electroosmotic flow has isotropic disturbances, which is conducive to destroying the formation of the heat transfer boundary layer, thereby enhancing heat transfer. In order to further enhance this disturbance, the thin electrode 10 on the inner wall of the flow channel is arranged asymmetrically.

[0089] In a preferred embodiment of the solar photovoltaic micro-channel cooling device driven by electroosmosis, the potential of the electrode 10 in the detachable channel 9 in the flow direction from the working fluid inlet 7 toward the working fluid outlet 8 gradually decreases.

[0090] In a preferred embodiment of the solar photovoltaic microchannel cooling device driven by electroosmosis, the potentials of the electrodes 10 in the detachable channel 9 in the flow direction from the working fluid inlet 7 toward the working fluid outlet 8 are distributed in an arithmetic progression.

[0091] In a preferred embodiment of the solar photovoltaic microfluidic channel cooling device driven by electroosmosis, a first pair of aligned electrodes 10 is provided at the working fluid inlet 7, and a second pair of aligned electrodes 10 is provided at the working fluid outlet 8. A plurality of electrodes 10 are provided on the inner wall of the detachable flow channel 9 between the working fluid inlet 7 and the working fluid outlet 8 and are staggered in a direction perpendicular to the working fluid flow.

[0092] For further information, see Figure 3 ,

[0093] The inlet 7 and the outlet 8 are located at two different directions outside the detachable flow channel 9 .

[0094] In a preferred embodiment of the solar photovoltaic microchannel cooling device based on electroosmosis drive, the potential of the first pair of electrodes 10 is at least 2000V, and the second pair of electrodes 10 is grounded.

[0095] In the preferred embodiment of the solar photovoltaic microchannel cooling device based on electroosmosis drive, the height of the detachable channel 9 is not more than 0.025 mm, the channel width is not more than 0.1 mm, and the thickness of the electrode 10 is not more than one third of the height of the detachable channel 9, so that the height of the detachable channel 9, the channel width, and the thickness of the electrode 10 match each other. With regard to this embodiment, considering that the electroosmotic flow is a relatively weak effect, if it is more than 1 mm, it will cause a larger size, and the requirements for the external voltage will be more stringent. This means that the size disclosed in this embodiment is to adapt to the selected photovoltaic panel calculation unit. Since the present disclosure utilizes solar photovoltaic self-generation, it is equivalent to realizing an electroosmotic self-drive, and the photovoltaic panel is cooled by electroosmotic self-drive to achieve the effect of increasing power.

[0096] In a preferred embodiment of the solar photovoltaic microchannel cooling device driven by electroosmosis, the electrolyte solution is a 0.001 mol / L NaCl electrolyte solution.

[0097] In a preferred embodiment of the solar photovoltaic micro-channel cooling device based on electroosmosis drive, the photovoltaic panel 1 is pivotally supported on a base 5, and the base 5 has a horizontal supporting surface.

[0098] In a preferred embodiment of the electroosmosis-driven solar photovoltaic microfluidic cooling device, the photovoltaic panel 1 is connected to a photovoltaic output system 4, the photovoltaic output system 4 is electrically connected to the electrode 10, and the photovoltaic output system 4 includes a junction box, a controller and a distribution cabinet.

[0099] In one embodiment, a solar photovoltaic microfluidic cooling device based on electroosmosis drive includes a photovoltaic panel 1 and a microfluidic cooling device 2 arranged on its back plate, wherein the external structure of the cooling device 2 is an aluminum shell 6, and the baffles and shell 6 placed inside it together constitute a micro-channel for cooling the working fluid, and the electrolyte solution flows through the channel to take away the heat from the photovoltaic panel 1. At the same time, a number of thin electrodes 10 are cross-arranged on the side wall of the microchannel, and an electric field is generated between the electrodes 10 due to the existence of the potential difference, thereby realizing the electroosmotic drive and control of the cooling working fluid. A photovoltaic output system 4 is also provided outside the cooling device 2, which is composed of a junction box, a controller and a distribution cabinet, and is used to apply an electric potential to the electrode 10. Due to the non-uniform arrangement of the electrodes 10 in the microchannel, an electric field perpendicular to the flow direction of the cooling working fluid will also be generated in the channel, thereby enhancing the electroosmotic disturbance of the cooling working fluid in the microchannel, destroying the formation of the heat transfer boundary layer, and achieving a significant improvement in the cooling efficiency of the photovoltaic panel 1. The present invention utilizes the electroosmosis phenomenon to drive the flow of cooling fluid (e.g., 0.001 mol / L NaCl solution) in the microchannel to efficiently cool the photovoltaic panel 1 without the need for a fluid mechanical pump. It has the advantages of a simple and flexible system structure and high cooling efficiency, and can provide a new microchannel cooling method for photovoltaic thermal management.

[0100] See also Figure 4 , in one embodiment,

[0101] The detachable flow channel 9 is used as a micro-channel, which is located on a plurality of electrodes 10 in the planar area on the back of the photovoltaic panel / the planar area of ​​the shell sheet, and a part of the plurality of electrodes 10 are located on the same straight line, which is perpendicular to the plurality of parallel straight line segments of the micro-channel.

[0102] For example, the three electrodes at +520V, +800V, and +1880V are not only located on the same side of the inner wall of the microchannel (Note: Figure 4 In the example, the three electrodes are all located on the upper side of the inner wall, and are all located on the first vertical line. For another example, the three electrodes at +440V, +880V, and +1800V are not only all located on the same side of the inner wall of the microchannel (Note: Figure 4 In the figure, the three electrodes are all located on the lower side of the inner wall) and are all located on the second vertical line, which is parallel to the first vertical line.

[0103] That is to say, the staggered electrodes described in the present invention can be arranged staggered on opposite sides of different sides of the inner wall of the microfluidic channel, and, at the multiple parallel straight line segments of the microfluidic channel, a part of the electrodes are located on one side of the inner wall of the microfluidic channel and on a first straight line; the other part of the electrodes are located on the other side opposite to the one side of the inner wall of the microfluidic channel and on a second straight line; the first straight line is parallel to the second straight line, and both are perpendicular to the multiple parallel straight line segments of the microfluidic channel.

[0104] For further information, see Figure 4 At the inlet and outlet, at the inner wall of the microchannel on one side, and at the other side opposite to the inner wall of the microchannel on the one side, two electrodes are arranged in a completely aligned but not staggered manner, for example, two +2000V electrodes at the inlet and two 0V electrodes at the outlet.

[0105] It should be noted that according to the principle of electroosmotic drive, the electrodes are used to apply an electric field, and it is not mandatory that all electrodes are completely aligned or all electrodes are staggered. The arrangement of the electrodes only needs to enable the electric field applied by the electrodes to be used for electroosmotic drive.

[0106] Exemplarily, the electrode is arranged on the inner wall of the baffle.

[0107] In one embodiment, the solar photovoltaic microfluidic cooling device based on electroosmosis drive includes:

[0108] The photovoltaic panel 1 is used to convert light energy into electrical energy and will generate a large amount of heat. When the temperature of the photovoltaic panel 1 is higher than the normal operating temperature, the photoelectric conversion efficiency decreases and the life of the photovoltaic module is reduced.

[0109] The cooling device 2 is disposed on the back of the photovoltaic panel 1 and is used to cool the photovoltaic panel 1, thereby improving the photoelectric conversion efficiency of the photovoltaic panel 1 and extending its service life.

[0110] The external photovoltaic output system 4 is used to integrate the electricity generated by photovoltaic power generation and output it to the cooling device 2 as the driving force of the electroosmotic flow, thereby realizing the self-driving of the electroosmotic cooling medium.

[0111] An electrolyte storage tank 3, which is connected to the inlet and outlet 8 of the cooling device 2 and is used to store the electrolyte solution;

[0112] The photovoltaic cooling device 2 has an aluminum thin baffle placed inside and multiple detachable aluminum semicircular arc channels installed outside. The baffle and the flow channel together constitute an electrolyte solution microchannel. The microchannel design can be achieved by changing the arrangement of the baffle or the channel; the height of the electrolyte solution microchannel is 0.025mm, and the flow channel width is 0.1mm; the cooling medium is a 0.001mol / L NaCl electrolyte solution, which can play a role in convection heat exchange and will not cause physical and chemical damage to the photovoltaic panel 1; a number of thin electrodes 10 are staggered on the side walls of the internal flow channel, and the aforementioned photovoltaic output system 4 is connected to the above electrodes 10 respectively. The potential of the electrode 10 placed at the inlet of the flow channel is +2000V, and the electrode 10 at the outlet 8 is grounded. Along the flow direction, the potential of each electrode 10 is distributed in an arithmetic progression. The external structure of the cooling device 2 is an aluminum square shell 6, which has an aluminum thin baffle placed inside and multiple detachable aluminum semicircular arc channels installed outside. The baffle and the flow channel together constitute an electrolyte solution microchannel. Microfluidic channel design can be achieved by changing the size and arrangement of baffles or channels.

[0113] The cooling effect of the solar photovoltaic microfluidic cooling device driven by electroosmosis is described below using multiple examples.

[0114] Example 1

[0115] This implementation case serves as a control group, simulating the steady-state temperature of the photovoltaic panel 1 only under the effect of ambient air cooling. In order to save computing resources, the simulation model uses the smallest unit of the photovoltaic module (the thickness uses the real thickness, and the side in the width direction is set as a periodic thermal boundary condition), with a length, width, and thickness of 2mm*1.9mm*3mm respectively. The simulation parameters are set as follows: the external ambient air temperature is 40℃, and there is natural convection between it and the photovoltaic panel 1, and the convection heat transfer coefficient h is 10W / (m 2 ·℃). It is mentioned in the above background technology that as the temperature increases, the photoelectric conversion efficiency of the photovoltaic panel 1 decreases. The relationship between the temperature T of the photovoltaic panel 1 and the photoelectric conversion efficiency η can be expressed as η=(0.3-(0.005*T[1 / ℃]))*100%(theoretically when T>60℃, η=0). Part of the light energy absorbed by the photovoltaic panel 1 is converted into electrical energy by the photovoltaic system, and the other part is converted into thermal energy to increase the temperature of the photovoltaic panel 1. The above-mentioned heating process can be equivalent to the effect of the body heat source in the photovoltaic panel 1 on it. The equivalent body heat source is also a function of linear change with temperature, Q=((1-(0.3-0.005*T[1 / ℃]))*1000 / 0.003)[W / m 3 ], where when T>60℃, Q=333333.3[W / m 3 ]. The simulation results are as follows:

[0116] Table 1 Steady-state temperature of photovoltaic panel 1 without cooling device

[0117]

[0118] Example 2

[0119] This implementation case is also used as a control group to simulate the temperature distribution of the photovoltaic panel 1 when the cooling medium is not passed through the cooling device 2. The size of the photovoltaic panel 1 is the same as that of Example 1, and a cooling device 2 is arranged on its back plate. The device can be regarded as a combination of a metal shell 6 and a cooling medium flow channel. At the same time, a certain number of copper heat-conducting structures are also installed in the metal shell to balance the temperature difference. The simulation parameter settings are the same as those of Example 1. The simulation results are as follows:

[0120] Table 2 Steady-state temperature of photovoltaic panel 1 when cooling device 2 is not supplied with working fluid

[0121]

[0122] Example 3

[0123] This implementation case is used as a control group to simulate the temperature distribution of the photovoltaic panel 1 when there is a static working medium in the flow channel of the cooling device 2. The size of the photovoltaic panel 1 is the same as that of Example 1, and the rest of the structure is the same as that of Example 2. Similarly, the simulation parameters are set the same as that of Example 1. The simulation results are as follows:

[0124] Table 3 Steady-state temperature of photovoltaic panel 1 when the working fluid in cooling device 2 is stationary

[0125]

[0126] Comparing the obtained results with those of Example 2, it can be seen that, since water has a certain heat storage capacity, even if the working medium is stationary, it still has a certain cooling effect on the photovoltaic panel 1.

[0127] Example 4

[0128] This implementation case is also a control group, simulating the photovoltaic water cooling effect without electric field disturbance. The geometric dimensions of the photovoltaic panel 1 and the cooling device 2 are shown above. The simulation parameters are set as follows: the external ambient air temperature is 40°C, and there is natural convection between it and the photovoltaic panel 1, and the convection heat transfer coefficient h is 10W / (m ２ ·℃). The equivalent body heat source size is the same as in case 1, Q = ((1-(0.3-0.005*T[1 / ℃]))*1000 / 0.003)[W / m 3 ], where when T>60℃, Q=333333.3[W / m 3 The coolant is 0.001 mol / L NaCl solution, the temperature is 20°C, the flow of the working fluid is driven by pressure difference, and the flow rate is 0.0555 mm 3 / s, outlet 8 pressure is atmospheric pressure. The simulation results are as follows:

[0129] Table 4 Steady-state temperature of photovoltaic panel 1 under pressure difference driven water cooling method

[0130]

[0131] Example 5

[0132] This implementation case is an experimental group, simulating the cooling effect of the cooling device 2 on the photovoltaic panel 1, especially comparing it with the water cooling method based on pressure difference drive mentioned in Example 4. The geometric dimensions of the photovoltaic panel 1 and the cooling device 2 are shown above. The simulation parameters are set as follows: the external air temperature is 40°C, and there is natural convection between it and the photovoltaic panel 1 and the cooling device 2 components, and the convection heat transfer coefficient h is 10W / (m 2 ·℃). The setting of the heat source of the photovoltaic panel 1 is the same as that of Example 4, Q = ((1-(0.3-0.005*T[1 / ℃]))*1000 / 0.003)[W / m 3 ], where when T>60℃, Q=333333.3[W / m 3 ]. The coolant is a 0.001 mol / L NaCl solution at a temperature of 20°C. Its flow is driven by electroosmosis, and the voltage of the driving electrode 10 at the inlet of the cooling medium flow channel is +2000 V. In order to enhance the disturbance of the medium in the flow channel, the electrodes 10 in the flow channel are placed in a staggered arrangement. The simulation results are as follows:

[0133] Table 5 Steady-state temperature of photovoltaic panel 1 based on electroosmotic driven water cooling method

[0134]

[0135] The simulation results show that the present invention can effectively reduce the operating temperature of the photovoltaic panel 1, and by comparing Example 5 with Example 4, it can be obtained that the electroosmosis driven water cooling method has a better heat exchange effect under the same flow rate, indicating that the electroosmosis driven method proposed in the present invention is more conducive to heat exchange than the traditional pressure difference driven method.

[0136] Figure 5 This is a temperature cloud diagram when the temperature of the photovoltaic panel reaches a steady state under different working conditions of a solar photovoltaic microfluidic cooling device driven by electroosmosis according to an embodiment of the present invention. It can be seen that the cooling effect of the liquid working fluid driven by electroosmosis is obvious.

[0137] Figure 6 The figure is a schematic diagram of the steady-state average temperature of the photovoltaic panel under different working conditions of the electroosmotic driven solar photovoltaic microfluidic cooling device according to an embodiment of the present invention. By comparison, it can be seen that the electroosmotic driven liquid working fluid cooling effect is obvious and is better than the traditional pressure driven liquid working fluid method. For further reference Figure 7 , the cooling medium temperature rises significantly and the heat exchange is sufficient.

[0138] Figure 8 It is a schematic diagram of the fluid streamline diagram in the flow channel of a solar photovoltaic microchannel cooling device driven by electroosmosis according to an embodiment of the present invention. It can be seen from the streamline diagram that under the action of the cross-arranged electrodes, the working fluid has a large disturbance in the flow channel.

[0139] The method of the solar photovoltaic microchannel cooling device based on electroosmosis drive comprises the following steps:

[0140] The cooling device 2 is installed on the back of the photovoltaic panel 1;

[0141] Based on the potential difference of the electrodes 10, an electric field is generated along the flow channel. Under the action of the electric field, the ions in the electrolyte solution move in a directional manner to generate electroosmotic flow. The unevenly arranged electrodes 10 generate an electric field perpendicular to the flow direction of the electrolyte solution, destroying the formation of the heat transfer boundary layer to reduce flow losses.

[0142] The heat generated during photovoltaic power generation is absorbed by the electrolyte solution, which is continuously cooled through circulation.

[0143] In one embodiment, the method comprises the following steps:

[0144] Step 1: Based on the potential difference of the electrode 10, an electric field is generated along the direction of the microchannel. The cations in the electrolyte solution move in a directional manner under the action of the electric field. Due to the hydration between the ions and the water molecules, the ions moving in a directional manner will move with the water molecules, thereby generating electroosmotic flow.

[0145] The second step: Based on the uneven arrangement of the electrodes 10, an electric field perpendicular to the flow direction of the cooling medium is generated to enhance fluid disturbance and destroy the formation of the heat transfer boundary layer, thereby enhancing heat exchange while reducing flow losses.

[0146] The third step: Based on the effects of heat conduction and heat convection, the heat generated during the photovoltaic power generation process is absorbed by the cooling medium, the temperature of the photovoltaic panel 1 is reduced, and the photovoltaic power generation efficiency can be improved.

[0147] Exemplarily, the present invention is installed on the back plate of a photovoltaic panel when in use, and its size matches the photovoltaic panel.

[0148] In addition, the present invention also has the following characteristics:

[0149] The cooling device is preferably made of copper or aluminum, which not only has good thermal conductivity but also has low cost and can meet the economic needs of industrial development, especially aluminum;

[0150] The microchannel may be a detachable structure, which is convenient for later cleaning and maintenance;

[0151] A plurality of thin electrodes are arranged equidistantly and staggered on the side wall of the microchannel of the cooling device, and the thickness thereof is such that no obvious obstruction to the flow of the fluid is produced;

[0152] When the cooling device is in operation, it relies on a portion of the electricity generated by photovoltaic power generation to drive the cooling medium through the electric field formed by the electrode potential difference. Compared with the traditional pressure-driven method, the electroosmotic drive method does not require an external fluid mechanical pump, has lower energy consumption, and uses the energy in the system to drive the electroosmotic flow. From the perspective of the entire system, this is a self-driven cooling device.

[0153] Furthermore, when the electrodes laid in the microchannel are arranged in a cross-shaped manner, they can be used to enhance the disturbance of the cooling medium in the channel, destroy the formation of the heat transfer boundary layer, and further enhance the heat exchange.

[0154] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields, and the above specific embodiments are only illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can also make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which belong to the protection of the present invention.

Claims

1. A solar photovoltaic microchannel cooling device based on electroosmosis drive, characterized in that: The cooling device is arranged on the back of a photovoltaic panel, and the photovoltaic panel is used for solar photovoltaic power generation; The cooling device is provided with a microchannel, The cooling device utilizes the electric energy obtained by photovoltaic power generation of the photovoltaic panel. Under the action of the electric energy, the cooling medium in the microchannel is driven based on the electroosmotic driving principle to realize cooling of the photovoltaic panel. The microchannel is formed by the outer shell of the cooling device and a plate connected to the outer shell. Within the range of the back of the photovoltaic panel, a single microchannel includes a plurality of straight line segments parallel to each other; in the range beyond the back of the photovoltaic panel, a single microchannel includes an arc-shaped connecting segment, and the arc-shaped connecting segment is used to connect two adjacent straight line segments. A thin electrode is arranged on the inner wall of the microchannel. The thickness of the thin electrode is based on not obviously hindering the flow of the cooling medium. The non-uniform arrangement of the thin electrodes in the microchannel will also generate an electric field perpendicular to the flow direction of the cooling medium in the flow channel, thereby enhancing the electroosmotic disturbance of the cooling medium in the microchannel. The outer shell is a thin plate, and the plate connected to the outer shell is a semi-enclosed and semi-closed plate, which is combined to form a hollow channel.

2. The solar photovoltaic microchannel cooling device based on electroosmosis drive according to claim 1, wherein: The cooling device is detachable.

3. The solar photovoltaic microchannel cooling device based on electroosmosis drive according to claim 1, wherein: The microchannel is detachable.

4. The solar photovoltaic microchannel cooling device based on electroosmosis drive according to claim 1, wherein: The cross-sectional area of ​​the microchannel is less than 0.0025 mm 2 .

5. The solar photovoltaic microchannel cooling device based on electroosmosis drive according to claim 1, wherein: The cooling medium of the microchannel circulates between the microchannel and a liquid storage tank outside the cooling device.

6. The solar photovoltaic microchannel cooling device based on electroosmosis drive according to claim 1, wherein: The shell and the photovoltaic panel are connected via a heat-conducting structure.

7. The solar photovoltaic microchannel cooling device based on electroosmosis drive according to claim 6, wherein: The heat-conducting structure is a heat-conducting column.

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