Photovoltaic-thermal assembly based on turbulence-enhanced cooling and heat collection function

Abstract

The application discloses a photovoltaic and photo-thermal assembly based on turbulence strengthening cooling and heat collecting functions, which comprises a shell, a light-transmitting plate, a photovoltaic cell, a substrate, first ribs and second ribs, wherein the photovoltaic cell is arranged between the light-transmitting plate and the substrate at the top of the shell, the top surface of the photovoltaic cell is attached to the bottom surface of the light-transmitting plate, and the bottom surface of the photovoltaic cell is attached to the top surface of the substrate; the back surface of the substrate is provided with a plurality of rows of the first ribs and the second ribs along the fluid flow direction. The photovoltaic and photo-thermal assembly provided by the application is verified by three-dimensional steady-state numerical simulation, the internal flow field of the photovoltaic and photo-thermal assembly forms a plurality of stable longitudinal vortexes under the coupling action of the first ribs and the second ribs in the front and rear rows, the boundary layer on the back surface of the substrate is effectively thinned, and the fluid in the flow channel is fully mixed in the area, so that the convective heat transfer effect is significantly enhanced. The application not only significantly improves the heat removal capacity of the fluid, effectively reduces the working temperature of the photovoltaic cell, and improves the photoelectric conversion efficiency of the photovoltaic cell.

Description

TECHNICAL FIELD

[0001] The application relates to a photovoltaic and photo-thermal assembly, in particular to a photovoltaic and photo-thermal assembly based on turbulence-enhanced cooling and heat collection. BACKGROUND

[0002] At present, most photovoltaic and photo-thermal assemblies rely on the setting of fins to increase the heat dissipation area and increase the local photovoltaic backboard thermal boundary disturbance to enhance the cooling of the photovoltaic assembly, improve the power generation efficiency, and meanwhile the fluid can absorb the heat energy of the photovoltaic assembly and be utilized. However, the thermal boundary disturbance of the fins of the existing photovoltaic and photo-thermal assembly to the photovoltaic backboard is usually local, and it is difficult to realize the overall disturbance of the thermal boundary layer, therefore, the industry urgently needs a new structure assembly to realize a photovoltaic and photo-thermal assembly with cooling and heat collection functions to improve the assembly efficiency. SUMMARY

[0003] The application aims to optimize and improve the local fluid boundary layer disturbance and insufficient heat exchange in the cooling system of the photovoltaic and photo-thermal assembly through structural innovation, and the application is a photovoltaic and photo-thermal assembly based on turbulence-enhanced cooling and heat collection.

[0004] The photovoltaic and photo-thermal assembly based on turbulence-enhanced cooling and heat collection provided by the application comprises a shell, a photovoltaic cell, a substrate, a light-transmitting plate, first fins and second fins, wherein the photovoltaic cell is arranged between the light-transmitting plate and the substrate at the top of the shell, the top surface of the photovoltaic cell is attached to the bottom surface of the light-transmitting plate, and the bottom surface is attached to the top surface of the substrate; the back surface of the substrate is provided with a plurality of rows of first fins and second fins along the fluid flow direction.

[0005] The material of the first fins is a metal with high thermal conductivity, for example, aluminum. The geometric configuration of the first fins is a 120-degree obtuse triangle structure, which is composed of two unequal short sides and a long side.

[0006] Four rows of six columns of first fins are arranged in the inner cavity of the shell, wherein, from left to right, each row of first fins is a group of two adjacent first fins, the first fins of each group in the first row and the third row are arranged in a "V" shape along the longer short side and are attached to the back surface of the substrate, the two first fins of each group are symmetrically arranged at an angle of 30 degrees to the fluid flow direction, the first fins of each group are non-perpendicularly arranged with the substrate, and the first fins are respectively inclined outward at an angle of 50 degrees to the substrate; the two longer short sides of the first fins of each group in the second row and the fourth row are arranged in an "eight" shape and are attached to the back surface of the substrate, the two first fins of each group are symmetrically arranged at an angle of 30 degrees to the fluid flow direction, the first fins of each group are non-perpendicularly arranged with the substrate, and the first fins are respectively inclined inward at an angle of 50 degrees to the substrate, and the first fins of each row are arranged at equal distances along the fluid flow direction.

[0007] The material of the second rib is high-thermal-conductivity metal, such as aluminum. The overall shape is an isosceles triangular member, which is divided into two parts of equal height, the upper part is an isosceles triangular plane, and the lower part is an isosceles trapezoidal 90° arc-shaped bending.

[0008] The inner cavity of the shell is equipped with four rows of second ribs, the lower base of the isosceles trapezoidal lower part is connected to the back of the substrate, the upper part of the isosceles triangular top corner points to the fluid advancing direction, and the plane where the upper part of the isosceles triangular shape is located is parallel to the fluid inflow direction, wherein the second ribs of the first row and the third row are arranged between the groups and the first ribs, and the second ribs of the second row and the fourth row are arranged between the groups of first ribs. The connecting line formed by the contact between the lower edge of the second rib and the back of the substrate is perpendicular to the main flow direction of the fluid, and the leading edge of the first rib in the same row is located on the same straight line.

[0009] The light-transmitting plate at the top of the shell is composed of two layers of frosted tempered glass plates, and the space between the two layers of glass is in a vacuum state to form a vacuum interlayer.

[0010] The two side plates and the bottom plate of the shell are filled with thermal insulation materials.

[0011] The working principle of the present application is as follows:

[0012] From the heat transfer mechanism, the heat of the substrate is efficiently absorbed by the fluid through two transmission paths, one is through the convective heat transfer between the back of the substrate and the fluid, and the other is through the convective heat transfer between the first rib and the second rib and the fluid. Due to the viscosity of the fluid, a flow boundary layer is formed between the fluid and the directly contacted substrate surface, and the thickness and internal turbulence of the boundary layer are the decisive factors affecting the convective heat transfer, so thinning the boundary layer and enhancing the internal disturbance of the boundary layer are the key to enhancing the convective heat transfer.

[0013] The photovoltaic and photo-thermal assembly based on the turbulence-enhanced cooling and heat collection function provided by the present application, when in use, sunlight transmits through the light-transmitting plate and irradiates onto the surface of the photovoltaic cell, part of the solar energy is converted into electrical energy, and part of the solar energy is converted into heat energy, at the same time, the temperature of the photovoltaic cell and the substrate attached thereto is increased. At this time, the temperature of the first rib and the second rib installed on the back of the substrate is also increased synchronously. When the fluid flows into the inner cavity of the shell at a certain speed, the high-speed fluid will flush the first rib and the second rib arranged in rows in turn, and under the comprehensive disturbance of the first rib and the second rib, the boundary layer of the heat exchange fluid on the back of the substrate can be fully disturbed, and the heat exchange is enhanced. The specific working process is as follows:

[0014] As fluid enters from the component inlet and flows along the substrate surface, a thick boundary layer gradually forms, leading to a decrease in heat transfer efficiency in the near-wall region. To mitigate this boundary layer effect, a group of first fins (in an outward-curving "V" shape) are arranged in the first row. When the fluid impacts the windward side of the first fin, its velocity decreases and its static pressure increases, while on the leeward side, its velocity increases and its static pressure decreases, thus creating a pressure difference and velocity gradient on both sides of the first fin. As a result, the fluid generates a pair of outward-extending longitudinal vortices on both sides of the first fin. These longitudinal vortices can entrain the high-speed main flow into the near-wall region, disrupting and thinning the original boundary layer, and significantly enhancing convective heat transfer between the substrate and the fluid.

[0015] As the fluid continues to flow through the first ribs arranged in the second row (forming an inward-curving "V" shape), a pressure difference and velocity gradient are also formed on both sides of the first ribs. However, the direction of the vortex is opposite to that of the outward-curving "V" shaped first ribs, generating a pair of inward-converging longitudinal vortices. These inward-converging longitudinal vortices can supplement the areas not fully covered by the previous row of ribs, allowing the fluid to undergo boundary layer disruption and renewal in more areas on the back of the substrate. Through the alternating action of the two types of longitudinal vortices, "outward extension" and "inward convergence," the overall flow field of the fluid on the back of the substrate is continuously disturbed, resulting in more uniform heat transfer enhancement.

[0016] Between each set of first ribs, a second rib is positioned. The upper part of the second rib is an isosceles triangle arranged in the flow direction, with a smooth leading edge to reduce wind resistance. The lower part is an isosceles trapezoid with a 90° bend, connected to the substrate, effectively altering the streamline distribution in the near-wall region. When fluid flows through the second rib, local flow acceleration occurs, forming normal flow branches at the trapezoidal bend. These branches further develop into new longitudinal vortices under shearing action with the main flow. These longitudinal vortices compensate for insufficient disturbance in the area created by the first rib alone, generating stronger disturbance and mixing effects on the central flow field and the near-wall boundary layer, thus significantly improving both local and overall convective heat transfer. Because the fluid carries away a large amount of heat, the temperature of the photovoltaic cell is effectively reduced, thereby improving its photoelectric conversion efficiency.

[0017] The fluid referred to in the above working process can be a gas or a liquid, such as air.

[0018] The top of the casing is designed with a double-layer vacuum structure of tempered glass with a velvet finish, which can effectively reduce heat loss through this surface. The insulation shell of the casing can effectively reduce heat loss from the photovoltaic thermal module.

[0019] The beneficial effects of this invention are:

[0020] The enhanced heat transfer photovoltaic-thermal module provided by this invention, verified by three-dimensional steady-state numerical simulation, demonstrates that its internal flow field, under the coupling effect of the first and second fins in the front and rear rows, forms multiple stable longitudinal vortices. This effectively thins the boundary layer on the back of the substrate, while the fluid within the flow channel undergoes thorough mixing in this region, significantly enhancing the convective heat transfer effect. Simulation results show that even with only the first fin arranged within the flow channel, stable and significant longitudinal vortices can be induced, leading to a significant reduction in the thickness of the thermal boundary layer on the back of the substrate. This results in a significantly higher average Nusselt number (Nu) compared to that of traditional module substrates, while the increase in the friction coefficient (f) is relatively small compared to that of traditional module substrates, resulting in a lower overall average coefficient of performance (COP) ((Nu / Nu0) / (f / f0)). 1 / 3 The coefficient of performance (COP) reaches 1.28, indicating that the first fin structure alone can achieve good enhanced heat transfer performance. Further arrangement of the second fin further enhances the formation of longitudinal vortices, expands the mixing and disturbance range, and increases the overall average COP to 1.299. The results show that the photovoltaic-thermal module of this invention can achieve higher heat transfer enhancement while maintaining low flow resistance, with an overall average COP value superior to those reported in existing literature. Therefore, this invention not only significantly improves the fluid's ability to remove heat, effectively reduces the operating temperature of photovoltaic cells, and improves their photoelectric conversion efficiency, but also achieves better overall heat transfer and photoelectric performance with lower drive power consumption, possessing significant engineering application value. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the photovoltaic thermal module described in this invention.

[0022] Figure 2 This is a schematic diagram showing the removal of the ribs in the inner cavity of the top cover shell of the photovoltaic thermal module according to the present invention.

[0023] Figure 3 This is a schematic diagram of the longitudinal section of the photovoltaic thermal module described in this invention.

[0024] Figure 4 This is a schematic cross-sectional view of the photovoltaic thermal module described in this invention.

[0025] Figure 5 This is a top view of the arrangement of ribs inside the housing of the photovoltaic thermal module according to the present invention.

[0026] Figure 6 This is a schematic diagram of the first rib structure described in this invention.

[0027] Figure 7 This is a schematic diagram of the second rib structure described in this invention.

[0028] Figure 8This is a schematic diagram of the combined structure of the first rib and the second rib described in this invention.

[0029] The annotations in the attached figures are explained as follows:

[0030] 1. Shell 2. Photovoltaic cell 3. Substrate 4. Light-transmitting plate 5. First rib 6. Second rib. Detailed Implementation

[0031] The invention will now be described in detail with reference to the accompanying drawings and embodiments. Please refer to... Figures 1 to 8 As shown:

[0032] The photovoltaic thermal module based on turbulence-enhanced cooling and heat collection functions provided by the present invention includes a housing 1, a photovoltaic cell 2, a substrate 3, a light-transmitting plate 4, a first rib 5, and a second rib 6. The photovoltaic cell 2 is disposed between the light-transmitting plate 4 and the substrate 3 at the top of the housing 1, with its top surface attached to the bottom surface of the light-transmitting plate 4 and its bottom surface attached to the top surface of the substrate 3. Several rows of first ribs 5 and second ribs 6 are arranged on the back side of the substrate 3 along the fluid flow direction.

[0033] The first rib 5 is made of a metal with high thermal conductivity, such as aluminum with a thermal conductivity of 237 W / m·K. Its geometric configuration is a 120° obtuse triangle structure, consisting of two short sides of unequal length and one long side.

[0034] The inner cavity of the housing 1 is equipped with four rows and six columns of first ribs 5. In each row, the first ribs 5 are arranged from left to right, with two adjacent first ribs 5 forming a group. In the first and third rows, each group of first ribs 5 is attached to the back of the substrate in a "V" shape along its longer short side. The two first ribs 5 in each group are symmetrical with each other at a 30° angle to the direction of fluid flow. The first ribs 5 in each group are not installed perpendicular to the substrate 3, and the first ribs 5 are inclined outward at a 50° angle to the substrate 3. In the second and fourth rows, the two longer short sides of each group of first ribs 5 are attached to the back of the substrate 3 in a "V" shape. The two first ribs 5 in each group are symmetrical with each other at a 30° angle to the direction of fluid flow. The first ribs 5 in each group are not installed perpendicular to the substrate 3, and are inclined inward at a 50° angle to the substrate 3. The first ribs 5 in each row are equidistant from each other in the direction of fluid flow.

[0035] The second rib 6 is made of a metal with high thermal conductivity, such as aluminum with a thermal conductivity of 237 W / m·K. The overall shape is an isosceles triangular component, which is divided into two parts with equal upper and lower heights. The upper part is an isosceles triangle in a planar shape, and the lower part is an isosceles trapezoid with a 90° arc bend.

[0036] The inner cavity of the housing 1 is equipped with four rows of second ribs 6. The lower base of the second ribs, which are isosceles trapezoids, is connected to the back of the substrate. The apex of the upper isosceles triangles points towards the direction of fluid flow, and the plane containing the upper isosceles triangles is parallel to the direction of fluid inflow. The second ribs in the first and third rows are arranged between the first ribs 5 in the groups, and the second ribs in the second and fourth rows are arranged between the first ribs 5 in the groups. The connecting line formed by the lower edge of the second rib 6 and the back of the substrate 3 is perpendicular to the main direction of fluid flow and is on the same straight line as the leading edge of the first rib 5 in the same row.

[0037] The light-transmitting plate 4 at the top of the shell 1 is composed of two layers of velvet tempered glass, with a vacuum between the two layers of glass to form a vacuum interlayer.

[0038] The two side plates and the bottom plate of the shell 1 are filled with thermal insulation material.

[0039] Working principle of the invention:

[0040] From the perspective of heat transfer mechanism, the heat of substrate 3 is efficiently absorbed by the fluid through two transfer paths: one is through convective heat transfer between the back of substrate 3 and the fluid, and the other is through convective heat transfer between the first fin 5 and the second fin 6 and the fluid. Due to the viscosity of the fluid, a flow boundary layer is generated between the fluid and the surface of substrate 3 in direct contact. The thickness of this boundary layer and the degree of internal turbulence are the determining factors affecting convective heat transfer. Therefore, thinning the boundary layer and enhancing the internal disturbance of the boundary layer are the key to enhancing convective heat transfer.

[0041] The photovoltaic-thermal module based on turbulence-enhanced cooling and heat collection provided by this invention, when in use, sunlight shines through the light-transmitting plate 4 onto the surface of the photovoltaic cell 2. Part of the solar energy is converted into electrical energy, and part into heat energy, simultaneously raising the temperature of the photovoltaic cell 2 and the substrate 3 to which it is attached. At the same time, the temperature of the first rib 5 and the second rib 6 mounted on the back of the substrate 3 also rises synchronously. When fluid flows into the housing 1 at a certain speed, the high-speed fluid sequentially washes over the row of first ribs 5 and second ribs 6. Under the combined disturbance of the first ribs 5 and second ribs 6, the boundary layer of the heat exchange fluid on the back of the substrate 3 is sufficiently disturbed, thus enhancing heat exchange. The specific working process is as follows:

[0042] As the fluid enters from the component inlet and flows along the surface of the substrate 3, a thick boundary layer gradually forms, leading to a decrease in heat transfer efficiency in the near-wall region. To mitigate this boundary layer effect, a group of first fins 5 (in an outward-curving "V" shape) are arranged in the first row. When the fluid impacts the windward side of the first fin 5, its velocity decreases and its static pressure increases, while on the leeward side, its velocity increases and its static pressure decreases, thus creating a pressure difference and velocity gradient on both sides of the first fin 5. As a result, the fluid generates a pair of outwardly extending longitudinal vortices on both sides of the first fin 5. These longitudinal vortices can entrain the high-speed main flow into the near-wall region, disrupting and thinning the original boundary layer, and significantly enhancing convective heat transfer between the substrate 3 and the fluid.

[0043] As the fluid continues to flow through the first ribs 5 arranged in the second row (in an inward-curving "V" shape), a pressure difference and velocity gradient are also formed on both sides of the first ribs 5. However, the direction of the vortex is opposite to that of the outward-curving "V" shaped first ribs 5, generating a pair of inward-converging longitudinal vortices. These inward-converging longitudinal vortices can supplement the areas not fully covered by the previous row of ribs, allowing the fluid to undergo boundary layer disruption and renewal in more areas on the back of the substrate. Through the alternating action of the two types of longitudinal vortices, "outward extension" and "inward convergence," the overall flow field of the fluid on the back of the substrate 3 is continuously disturbed, resulting in more uniform heat transfer enhancement.

[0044] Between each set of first ribs, a second rib 6 is provided. The upper part of the second rib is an isosceles triangle arranged in the flow direction, with a smooth leading edge to reduce wind resistance. The lower part is an isosceles trapezoid with a 90° bend and connected to the substrate 3, effectively altering the streamline distribution in the near-wall region. When fluid flows through the second rib 6, local flow acceleration occurs, forming normal flow branches at the trapezoidal bend. These branches further develop into new longitudinal vortices under shearing action with the main flow. These longitudinal vortices compensate for the insufficient disturbance area formed by the first rib 5 alone, generating stronger disturbance and mixing effects on the central flow field and the near-wall boundary layer, thus significantly improving the local and overall convective heat transfer effect. Because the fluid carries away a large amount of heat, the temperature of the photovoltaic cell 2 is effectively reduced, thereby improving its photoelectric conversion efficiency.

[0045] The fluid referred to in the above working process can be a gas or a liquid, such as air.

[0046] The top of the housing 1 is set with a double-layer vacuum structure of tempered glass with a velvet finish, which can effectively reduce heat loss through this surface. The heat insulation shell of the housing 1 can effectively reduce heat loss of the photovoltaic thermal module.

[0047] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A photovoltaic-thermal assembly based on the enhanced cooling and heat collection function of the spoiler, comprising a shell, a light-transmitting plate, a photovoltaic cell, a base plate, and a first fin; characterized in that: The material of the first rib is high-thermal-conductivity metal, and the geometric configuration is a 120° obtuse triangle structure composed of two unequal short sides and a long side. Four rows of six columns of first ribs are assembled in the inner cavity of the shell, wherein, from left to right, each row of first ribs is a group of two first ribs, the first and third rows of first ribs are arranged in a "V" shape along the longer short side and are attached to the back of the substrate, the two first ribs in each group are symmetrically arranged at an angle of 30° to the fluid flow direction, the first ribs in each group are non-perpendicular to the substrate and are inclined outward at an angle of 50° to the substrate, the second and fourth rows of first ribs are arranged in an "eight" shape along the longer short side and are attached to the back of the substrate, the two first ribs in each group are symmetrically arranged at an angle of 30° to the fluid flow direction, the first ribs in each group are non-perpendicular to the substrate and are inclined inward at an angle of 50° to the substrate, and the first ribs in each row are equidistantly arranged in the fluid flow direction. The second rib is also included, the material of the second rib is high-thermal-conductivity metal, and the overall shape is an isosceles triangle component, which is divided into two parts of equal height, the upper part is an isosceles triangle in a planar shape, and the lower part is an isosceles trapezoid bent in a 90° circular arc shape. Four rows of second ribs are assembled in the inner cavity of the shell, the lower base of the isosceles trapezoid of the lower part is connected to the back of the substrate, the top corner of the isosceles triangle of the upper part points to the fluid flow direction, and the plane on which the isosceles triangle of the upper part is located is parallel to the fluid flow direction, wherein the second ribs in the first and third rows are arranged between the first ribs in the groups, and the second ribs in the second and fourth rows are arranged between the first ribs in the groups, the connecting line formed by the contact between the lower edge of the second rib and the back of the substrate is perpendicular to the main fluid flow direction, and the leading edge of the first rib in the same row is located on the same straight line; the photovoltaic cell is arranged between the light-transmitting plate on the top of the shell and the substrate, the top surface of the photovoltaic cell is attached to the bottom surface of the light-transmitting plate, and the bottom surface is attached to the top surface of the substrate, and the back of the substrate is provided with a plurality of rows of first ribs and second ribs along the fluid flow direction.

2. The photovoltaic-thermal assembly based on the enhanced cooling and heat collection function of the spoiler according to claim 1, characterized in that: The light-transmitting plate on the top of the shell is composed of two layers of frosted tempered glass plates, and the space between the two layers of glass is in a vacuum state to form a vacuum interlayer.

3. The photovoltaic-thermal assembly based on the enhanced cooling and heat collection function of the spoiler according to claim 1, characterized in that: The two side plates and the bottom plate of the shell are filled with thermal insulation materials.

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