CN114294840A

CN114294840A - Flat plate type solar heat collector with reflector

Info

Publication number: CN114294840A
Application number: CN202210032670.6A
Authority: CN
Inventors: 侯蓉; 张鹏飞; 王晓怡; 陈鹏云; 何印; 马振华; 冀云彪; 刘磊磊
Original assignee: North University of China
Current assignee: North University of China
Priority date: 2022-01-12
Filing date: 2022-01-12
Publication date: 2022-04-08

Abstract

The invention provides a flat plate type solar heat collector with a reflector, which comprises a heat absorbing plate, a shell, a transparent cover plate and a heat insulating material, wherein the transparent cover plate is arranged at the top of the shell, the heat absorbing plate is arranged in the shell, the heat insulating material is arranged in the inner side surface of the shell so as to form a heat insulating space in the shell, the reflector is arranged between the heat absorbing plate and the transparent cover plate, and the reflector is connected with the edges of the heat absorbing plate and the transparent cover plate. The invention provides a flat plate solar collector with a novel structure, which is characterized in that a reflector is arranged, so that heat which is irradiated into the collector by sunlight but not irradiated onto a heat absorbing plate is reflected to the upper layer of the heat absorbing plate by the reflector, and the heat collection is further enhanced.

Description

Flat plate type solar heat collector with reflector

Technical Field

The invention belongs to the field of solar energy, and particularly relates to a solar heat collection device 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 collecting device, 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 heat collector, an absorption part for absorbing solar radiation is required, and the structure of the heat collector plays an important role in absorbing solar energy.

Aiming at the problems, the invention improves on the basis of the previous invention and provides a novel flat-plate solar heat collection system, thereby solving the problems of low heat exchange quantity and uneven heat exchange of a heat collector.

Disclosure of Invention

The invention provides a novel flat plate type solar heat collector, which can reduce the pump power consumption, strengthen heat collection and realize the column array heat collector scheme with uniform temperature distribution, thereby solving the technical problems in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the flat plate type solar heat collector with the reflector comprises a heat absorbing plate, a shell, a transparent cover plate and a heat insulating material, wherein the transparent cover plate is arranged at the top of the shell, the heat absorbing plate is arranged in the shell, and the heat insulating material is arranged inside the inner side surface of the shell so as to form a heat insulating space inside the shell.

Preferably, the reflector has a circular arc structure, and the circular arc is curved toward the housing.

Preferably, the reflector is a two-piece plane mirror bending structure, and the bending structure is bent towards the shell direction.

Preferably, the reflecting mirror is a multi-piece plane mirror bending structure.

Preferably, the interior of the housing is filled with an inert gas.

Preferably, a lens is provided on the transparent cover plate.

Preferably, the heat absorbing plate is provided with three layers, namely a lower layer, a middle layer and an upper layer from bottom to top, a fluid inlet and a fluid outlet are arranged on the lower side of the lower layer, a fluid inlet flow path and a fluid outlet flow path are arranged on the upper side of the lower layer, the fluid inlet is communicated with the fluid inlet flow path, the fluid outlet is communicated with the fluid outlet flow path, the fluid inlet flow path is arranged at the first end part of the upper side and extends along the first end along the first direction, and the fluid outlet flow path is arranged at the middle position of the upper side and extends along the direction vertical to the fluid inlet flow path;

the middle layer comprises an inlet pipe inflow flow path and an outlet pipe outflow opening which are arranged on the lower side, and an inlet pipe and an outlet pipe which are arranged on the upper side of the middle layer, the inlet pipe inflow flow path comprises two parallel pipes which are arranged on two opposite end parts, the extending direction of the inlet pipe inflow flow path is vertical to the first direction, and one tail end of each inlet pipe inflow flow path is communicated with the fluid inlet flow path; the outlet of the outlet pipe is arranged at the middle position of the upper side of the middle layer and is communicated with the fluid outlet flow path; the inlet pipe is communicated with the inlet flow path of the inlet pipe, and the outlet pipe is communicated with the outlet of the outlet pipe; the inlet pipes and the outlet pipes are arranged at intervals and are arranged between the two inlet pipe inflow flow paths, the inlet pipes are communicated with the two inlet pipe inflow flow paths, and the outlet pipes are communicated with the inlet pipes through the lower side of the upper layer;

the upper layer comprises a plurality of radiators arranged on the lower side and extending downwards from the lower side, and gap flow paths for flowing fluid are arranged among the radiators.

Preferably, the fluid inlet and the fluid outlet are provided at opposite ends, respectively.

Preferably, the outlet pipes are rectangular closed structures, and the space between the outlet pipes forms the inlet pipe.

Preferably, the heat sink is of cylindrical construction.

Compared with the prior art, the invention has the following advantages:

1) the invention provides a flat plate solar collector with a novel structure.A reflector is arranged between a heat absorbing plate and a transparent cover plate, so that heat of sunlight irradiating the heat collector but not irradiating the heat absorbing plate is reflected to the upper layer of the heat absorbing plate through the reflector, and the heat collection is further enhanced.

2) The invention improves the prior flat plate heat collecting plate, the inflow flow path of the inlet pipe is divided into two paths, so that the directions of the fluid flowing into the inlet pipe are divided into two paths, and the fluid is impacted in the inlet pipe, so that the impact of the fluid on the column array layer can be strengthened, and the integral heat radiation performance is improved.

3) According to the invention, the inlet pipe is in a tapered structure which gradually shrinks along the flow direction, and the outlet pipe is in a tapered structure which gradually enlarges along the flow direction, so that the fluid can be uniformly distributed, the integral flow resistance is reduced, and therefore, the uniformity of the temperature distribution of the bottom surface can be improved, and the power consumption of the pump can be reduced.

4) The invention selects the variable-diameter cylinder through the cylinder, and the cylinder on the outlet pipe side has better heat exchange capability, thereby strengthening the integral heat exchange and realizing the uniform distribution of the bottom surface temperature.

5) The flat plate collector has compact structure and large internal heat exchange area, and can realize the miniaturization of the structure.

Drawings

FIG. 1 is a schematic view of the overall structure of the flat plate collector of the present invention;

FIG. 2 is an exploded view of the overall structure of the flat plate absorber plate of the present invention;

FIG. 3 is a top view of the flat plate absorber plate of the present invention;

FIG. 4 is a view of the underside and topside of the middle layer of the flat plate absorber plate of the present invention;

FIG. 5 is a schematic flow diagram of the inlet and outlet tube structures of the flat plate absorber plate of the present invention;

fig. 6 is a structural view of the whole and part of the column array of the flat plate absorber plate of the invention.

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.

Fig. 1-6 disclose a flat-plate solar collector. As shown in fig. 1, the flat plate type solar heat collector comprises a heat absorbing plate 1, a shell 2, a transparent cover plate 3 and a heat insulating material, wherein the transparent cover plate 3 is arranged at the top of the shell 2, the heat absorbing plate 1 is arranged in the shell 2, and the heat insulating material is arranged inside the inner side surface of the shell 2 so as to form a heat insulating space inside the shell 2. Preferably, a lens is arranged on the transparent cover plate 3 to facilitate heat collection.

As shown in fig. 2, the absorber plate 1 is provided with a lower layer 11, a middle layer 12 and an upper layer 13 from bottom to top, and the three layers are combined to form the complete absorber plate 1. The lower absorber plate layer 13 connects the inlet pipe 4 and the outlet pipe 5.

As a modification, a mirror 6 is provided between the absorber plate 1 and the transparent cover plate 3, as shown in fig. 1. The reflector is connected with the heat absorbing plate and the edge of the transparent cover plate 3. By arranging the reflector 6, heat which is irradiated into the heat collector by sunlight but not irradiated onto the heat absorbing plate is reflected to the upper layer of the heat absorbing plate by the reflector, so that heat collection is further enhanced.

Preferably, the inside of the housing 2 is filled with an inert gas.

As shown in fig. 2 and 3, the lower layer 11 includes an upper side and a lower side, the lower side is provided with a fluid inlet 111 and a fluid outlet 114, and the fluid inlet 111 and the fluid outlet 114 are respectively connected with the inlet pipe 4 and the outlet pipe 5. The upper side is provided with a fluid inlet flow path 112 and a fluid outlet flow path 113, the fluid inlet 111 is communicated with the fluid inlet flow path 112, the fluid outlet 114 is communicated with the fluid outlet flow path 113, the fluid inlet flow path 112 is provided at a first end portion of the upper side and extends in a first end direction, i.e., in a first direction, and the fluid outlet flow path 112 is provided at a middle position of the upper side and extends in a direction perpendicular to the fluid inlet flow path (the first direction).

The top and bottom views of fig. 4 show the top and bottom side of the middle layer 12, respectively. As shown in fig. 4, the middle layer 12 includes an inlet pipe inflow flow path 121 and an outlet pipe outflow port 124 provided on the lower side, and an inlet pipe 122 and an outlet pipe 123 provided on the upper side, the inlet pipe inflow flow path 121 includes two inlet pipe inflow flow paths 121 provided at opposite ends in parallel with each other, the extending direction of the inlet pipe inflow flow paths 121 is perpendicular to the first direction and one end of each inlet pipe inflow flow path 121 communicates with the fluid inlet flow path 112; the outlet pipe outlet 124 is provided at a middle position on the upper side of the middle layer and communicates with the fluid outlet channel 113; the inlet pipe 122 communicates with the inlet pipe inflow flow path 121, and the outlet pipe 123 communicates with the outlet pipe outflow port 124; the inlet pipe 122 and the outlet pipe 123 are disposed at intervals and between the two inlet pipe inflow flow paths 121, the inlet pipe 122 communicates with the two inlet pipe inflow flow paths, and the outlet pipe 123 does not directly communicate with the two inlet pipe inflow flow paths. The outlet pipe 123 communicates with two inlet pipe inflow flow paths through the lower side of the upper layer.

Preferably, as shown in fig. 4, outlet pipes 123 are rectangular closed structures, and the space between outlet pipes 123 constitutes inlet pipe 122. The outlet pipe is communicated with the inlet pipe through the lower side of the upper layer.

As shown in fig. 6, the upper layer 13 includes a plurality of heat radiators 131, preferably pillars 131, provided on the lower side and extending downward from the lower side, and interstitial flow paths 132 for fluid flow are provided between the heat radiators 131.

The working process of the invention is as follows: the fluid flows into the fluid inlet flow path 112 from the fluid inlet 111, then flows into the inlet tube inflow flow path 121 and is distributed to the inlet tube 122, and the fluid is collided between the inlet tube 122 and the fluid due to the opposite flow directions, and is forced to flow into the column gap flow path 132, and absorbs the heat conducted by the column 131 in the process, so that the heat absorption effect is realized. After heat absorption, the fluid flows into the outlet pipe 123, flows out through the outlet pipe outlet 124, then flows into the fluid outlet flow path 113, and flows out through the fluid outlet 114, so that the whole flowing heat exchange process is completed, the fluid is driven by an external driving pump, and continuously flows into the heat absorption plate to continuously absorb heat of solar energy, and heat collection is realized.

The invention improves the prior flat plate collector, and the inflow flow paths of the inlet pipe are two, so that the directions of the fluid flowing into the inlet pipe are two, and the fluid is impacted in the inlet pipe, thereby the impact of the fluid on the column array layer can be strengthened, and the integral heat radiation performance is improved. Because the hydraulic diameter of the inlet pipe is larger, the gap size of the lower column array is smaller, and the flow velocity of the fluid is larger, more fluid can collide in the inlet pipe and then transfer to the lower column array layer.

Preferably, the heat sink is of a cylindrical structure, preferably a cylindrical structure.

Preferably, the distribution density of the heat sink is smaller and smaller along the direction of fluid flow (i.e. from the two inlet pipes into the flow path towards the middle). By such distribution, the flow resistance at the middle position is reduced, so that the impact force of the fluid at the middle position is larger, and the heat transfer is further enhanced. Preferably, the distribution density of the heat sink is increased with a smaller and smaller amplitude along the direction of fluid flow (i.e. from the two inlet ducts into the flow path towards the middle). By such distribution, the heat transfer is further enhanced.

Preferably, the inlet pipe 122 is selected to have a tapered structure that gradually narrows in the flow direction, and the outlet pipe 123 is selected to have a tapered structure that gradually widens in the flow direction. Through so setting up, can make fluid evenly distributed reduce whole flow resistance simultaneously, consequently it both can improve bottom surface temperature distribution homogeneity, can reduce pump work consumption again, promotes the continuous increase of fluidic velocity of flow, and further striking dynamics further strengthens the impact of fluid to the column array layer, improves whole thermal-arrest performance.

Preferably, the heat exchange capacity of cylinder 131 at the location of outlet pipe 123 is greater than the heat exchange capacity at the location of inlet pipe 122. Through the pointed heat exchange at the position of the reinforced outlet pipe 123, the heat distribution can be further more uniform, the integral heat exchange is reinforced, and the uniform distribution of the bottom surface temperature is realized. Because the fluid has not taken place violent heat transfer process with lower floor cylinder array layer yet in import pipe department, consequently the fluid temperature is lower this moment, it is great with cylinder array layer heat transfer difference in temperature, the heat transfer is comparatively violent, and when the fluid stayed export pipe department, because some heat has been absorbed in the flow process before this, the fluid temperature rises, consequently reduce with the heat transfer difference in temperature of lower floor cylinder layer, heat transfer capacity compares with import pipe department and reduces by a wide margin, consequently this can lead to the cylinder of import pipe department to be taken away the heat many, the heat that the cylinder was taken away by the outlet pipe department is few, this can cause heat sink bottom surface temperature distribution inequality. When the cylinder is set to be a variable-diameter cylinder, the diameter of the cylinder at the side of the inlet pipe is larger, and the heat conduction resistance is also larger. This inhibits the fluid from absorbing heat therefrom, thereby enhancing heat transfer from the fluid at the outlet pipe to compensate for the impairment of the heat transfer process caused by the gradual rise in temperature of the fluid. It should be noted that the diameter difference between the inlet and outlet columns may not be too large, which may cause weak heat exchange at the inlet pipe and too strong heat exchange at the outlet pipe, which may also cause uneven temperature distribution. Therefore, according to the simulation structure and the practical application thereof, the invention proposes that the diameter ratio of the cylinder at the side of the inlet pipe to the cylinder at the side of the outlet pipe is more suitable between 1.5 and 2.

Preferably, the fluid inlet 111 and the fluid outlet 114 are disposed at opposite ends, respectively. The fluid flow is more uniform and the distribution area is wide.

Preferably, as shown in fig. 3, the fluid outlet channel 113 has a tapered structure, and the flow area thereof gradually increases from the fluid inlet channel 112 side along the extending direction. The inlet pipe of the fluid is gradually contracted along the flow direction, the flow area of the outlet pipe is gradually increased along the flow direction because when the fluid flows through the inlet pipe, the fluid is more prone to flow along the pipe, a large amount of fluid is gathered at the tail end, the cylinder area is distributed with more fluid, and therefore the fluid is unevenly distributed, the inlet pipe is in a conical contraction structure, the fluid can collide with the upper surface of the pipe in the flow process, the momentum of the fluid is changed, downward speed is generated, the fluid is more evenly distributed, and the overall temperature distribution of the heat sink is more even. The outlet pipe is selected to have a tapered structure which gradually increases in the flow direction because the fluid gradually increases in the flow direction of the outlet pipe, for example, the fluid flowing through the root region of the outlet pipe is only a part, and the fluid after being collected is all in the outlet region, so that the overall flow pressure drop can be reduced by adopting the structure, and the structure can be cooperated with the inlet pipe to enable the overall fluid distribution to be more uniform, which is proved in simulation work.

Preferably, as shown in fig. 4, a plurality of outlet pipe outflow ports 124 are provided, and each outlet pipe outflow port 124 corresponds to a lower outlet pipe one by one.

Preferably, as shown in fig. 4, the inlet pipe inflow flow path penetrates the entire middle layer in the up-down direction.

Preferably, the distribution density of the cylinders at the outlet tube location is greater than the distribution density of the cylinders at the inlet tube location. Through the pointed heat exchange at the position of the reinforced outlet pipe 123, the heat distribution can be further more uniform, the integral heat exchange is reinforced, and the uniform distribution of the bottom surface temperature is realized.

Preferably, the heat dissipation body is of an elastic structure, the heat dissipation body can be flushed when fluid flows through the elastic structure, and the heat dissipation body can swing in a pulsating mode, so that descaling is promoted, turbulence is caused by vibration, and heat transfer can be enhanced.

Preferably, the heat radiating body may be a spring.

Preferably, the heat-conducting columns become more and more elastic in the direction of fluid flow (i.e. from the two inlet ducts into the flow path towards the middle). As researches show that the fluid is easier to scale at the position of the middle part and the degree of scaling along the flowing direction of the fluid is more and more serious, the aim of further descaling and heat transfer enhancement is achieved by setting the elasticity degree to be continuously increased, the large-elasticity heat radiator is reduced, and the cost is reduced.

It is further preferred that the resilience of the heat conducting pillars increases with increasing magnitude in the direction of fluid flow (i.e. from the two inlet ducts into the flow path towards the middle). The change is found according to research, accords with the scaling rule, and can further reduce the cost, improve the heat exchange efficiency and reduce the scaling.

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. The flat plate type solar heat collector with the reflector comprises a heat absorbing plate, a shell, a transparent cover plate and a heat insulating material, wherein the transparent cover plate is arranged at the top of the shell, the heat absorbing plate is arranged in the shell, and the heat insulating material is arranged inside the inner side surface of the shell so as to form a heat insulating space inside the shell.

2. The solar collector of claim 1, wherein the reflector is in the form of a circular arc, the circular arc being curved in the direction of the housing.

3. The solar collector of claim 1, wherein the reflector is a two-piece flat mirror folded structure, the folded structure being folded toward the housing.

4. The solar collector of claim 1 wherein the reflector is a multi-piece, plane mirror fold structure.

5. A solar collector as claimed in claim 1, wherein the interior of the housing is filled with an inert gas.

6. A solar collector as claimed in claim 1, wherein the transparent cover plate is provided with a lens.

7. The solar collector of claim 1, wherein the absorber plate is provided with three layers, from bottom to top, a lower layer, a middle layer and an upper layer, a lower side of the lower layer is provided with a fluid inlet and a fluid outlet, an upper side of the lower layer is provided with a fluid inlet flow path and a fluid outlet flow path, the fluid inlet is communicated with the fluid inlet flow path, the fluid outlet is communicated with the fluid outlet flow path, the fluid inlet flow path is arranged at a first end of the upper side and extends along a first direction along a first end, and the fluid outlet flow path is arranged at a middle position of the upper side and extends along a direction perpendicular to the fluid inlet flow path;

8. A solar collector according to claim 7, wherein the fluid inlet and the fluid outlet are provided at opposite ends, respectively.

9. A solar collector as claimed in claim 7, wherein the outlet tubes are rectangular enclosures, the spacing between the outlet tubes forming the inlet tubes.

10. A solar collector as claimed in claim 7, wherein the heat sink is of cylindrical configuration.