CN206387126U - Straight ribbed pipe inserts fin slot light collection evacuated solar collector - Google Patents

Abstract

The utility model discloses a trough-type concentrating vacuum solar heat collector with straight rib tubes inserted into fins, which comprises a vacuum heat collector and a trough-type concentrator, and the vacuum heat collector is arranged at the light-gathering position of the trough-type concentrator The vacuum collector includes a straight-through glass vacuum sleeve, a vacuum layer is formed between the outer glass tube and the inner glass tube, the inner glass tube is equipped with a straight rib tube, and the straight rib tube is fixed by a spring; Two arc-shaped heat shields are arranged; two fins are installed outside the straight rib tube. The utility model has the advantages of high light concentrating heat collection efficiency, relatively uniform heat flux density received by the heat collecting tube, less external radiation heat loss of the inner glass tube, less fouling of the heat collecting tube, and long service life.

Description

Straight rib tube finned groove concentrating vacuum solar collector

technical field

The utility model relates to the field of green energy, in particular to a trough-type vacuum solar collector with finned straight rib tubes.

Background technique

With the continuous popularization of green buildings and building energy conservation, the development and utilization of solar collectors have been paid more and more attention. Due to the relatively low flux density of solar energy, in practical large-scale applications, the temperature of the heat-collecting working medium of common flat-plate solar collectors is low, the heat loss is large, and the thermal efficiency is very low.

The concentrating glass vacuum tube solar collector can further increase the collection area of solar radiation energy flow and the working temperature of the collector on the basis of making full use of the light weight and high efficiency of the glass vacuum tube collector, and effectively expand the traditional vacuum tube collector. range of application and thermal energy quality. Except for a few applications in the field of civil hot water, it is mainly used in solar thermal power generation or other industrial fields, such as food processing, metal and material processing, chemical industry, seawater desalination and other fields. The temperature requirements of these fields generally range from 100°C to 300°C.

The trough solar concentrating collector includes a concentrator and a vacuum heat collecting tube. After receiving the light reflected by the concentrator mirror on the vacuum heat collecting tube, the heat flux density on the surface of the heat collecting tube is uneven in actual operation, that is, the heat flux density on the side facing the reflector is relatively large, and the heat flux density on the other side is relatively small, and therefore It will cause a large temperature difference in the circumferential direction, cause stress differences, cause pipe deformation, reduce the airtightness of the entire heat collecting tube, and at the same time greatly shorten the life of the heat collecting tube. Questions are necessary.

The all-glass solar vacuum tube applied to the trough concentrating collector, the outer wall of the inner glass tube of the solar vacuum heat collecting tube is coated with a selective absorption coating, and the inner glass tube can reach a medium and high temperature of 400°C or even above 400°C , the heat flux density of the inner glass tube for radiating heat to the outside will increase sharply, and at the same time, the emissivity of the inner glass tube at medium and high temperatures will reach 10%, resulting in greater heat loss from the inner glass tube. When the temperature of the inner glass tube is high, the problem of the large heat loss of the vacuum heat collecting tube through the inner glass inner tube due to external radiation becomes very critical.

The heat collector tube is the key inner glass part of the heat collector. There are many types of traditional solar vacuum heat collector tubes. The traditional all-glass vacuum tube heat collector tube has high thermal efficiency, but it cannot operate under pressure, and it is easy to crack and scale, so it is not suitable for use. In large-area solar water heating systems, it is mostly used as a heat collecting component for household solar water heaters. Improving the structure of heat collecting tubes, strengthening heat transfer and reducing heat loss to improve its performance has important academic significance for the development of efficient, reliable, and low-cost new vacuum heat collecting tubes and heat collectors.

At present, improved concentrators such as structures and reflective film materials are widely used at home and abroad. There is almost no improvement in the structure of vacuum heat collectors to achieve secondary or multiple concentrating and improve the problem of uneven heat flux. In view of the uneven heat density received by the vacuum heat collection tube caused by the trough-type concentration and the large heat loss of the inner glass tube of the heat collection tube in the case of medium and high temperature, the thermal efficiency of the solar vacuum heat collection tube itself is not high, and it is easy to scale, etc. Problem, the applicant has designed the utility model.

Utility model content

The purpose of this utility model is based on the existing trough-type concentrating solar heat collector technology, starting from three important links: 1) the process of concentrating the incident sunlight at different angles to the heat collecting tube; 2) the heat collecting tube will The conversion of sunlight into heat is the light-to-heat conversion process; 3) the heat dissipation loss process of the heat collecting tube, which solves the existing technical problems and improves its solar energy utilization rate and light-gathering heat collection efficiency.

In order to achieve the purpose of the above utility model, the technical solution of the utility model is: a straight rib tube finned trough concentrating vacuum solar heat collector, including a vacuum heat collector and a trough concentrator, the trough concentrator The optical device is set with a trough reflective mirror that can reflect and gather sunlight, and the vacuum heat collector is set at the concentrating position of the trough concentrator;

The vacuum heat collector includes a straight-through glass vacuum sleeve, and the straight-through glass vacuum sleeve includes an outer glass tube and an inner glass tube. A vacuum layer is formed between the outer glass tube and the inner glass tube, and the inner glass tube The middle wear is equipped with a straight rib tube for the passage of heat medium fluid. The straight rib tube is fixed on the axis of the inner glass tube by a spring, and a sealing ring is installed at both ends of the inner glass tube; two arc-shaped tubes are arranged in the vacuum layer. The heat shield, the heat shield respectively extends toward the inner side of the outer glass tube and the direction of the mirror surface of the trough concentrator along the two ends of the diameter of the outer glass tube perpendicular to the symmetrical line of the mirror of the trough concentrator;

Two fins are installed on the outside of the straight rib tube, and the two fins are arranged along the radial direction of the straight rib tube. The mirror symmetry lines of the optics coincide.

As a preference of the present utility model, the central angle of the inner glass tube covered by the two heat insulation boards is 60°; the included angle between the two fins is 120°.

As a preference of the present utility model, the vacuum heat collector and the trough concentrator are fixedly installed on a rotating device that tracks the position of the sun.

As a preference of the present invention, the inner surface of the trough concentrator is provided with an evaporated aluminum film that enhances reflectivity.

As a preference of the present invention, the material of the fins is copper or aluminum, the thickness is 0.08mm-1mm, and the length is 100mm shorter than that of the inner glass tube.

As a preference of the present invention, the material of the heat shield is aluminum alloy, the side of the heat shield corresponding to the inner glass tube is a reflective surface with high reflectivity, and the side corresponding to the outer glass tube is Heat absorbing surface provided with selective absorbing coating.

As a preference of the present invention, the outer surfaces of the fins and the straight-finned tubes are coated with spectrally selective coatings.

The beneficial effects of the utility model are:

Compared with the best existing technology, the utility model has the advantages of high light-gathering and heat-collecting efficiency, relatively uniform heat flux density received by the heat-collecting tube, less external radiation heat loss of the inner glass tube, less fouling of the heat-collecting tube, and long service life. :

1. There are two arc-shaped heat shields in the vacuum layer, which reflect the primary reflected light from the concentrator for the second time. The trough concentrator and the secondary reflector can gather sunlight at different angles from the top and bottom of the cut-off surface. While fully absorbing the direct light, it can effectively use the scattered light in the environment, effectively improve the uneven heat flux received by the heat collecting tube, and can reflect most of the heat from the straight rib tube covered by the heat shield to the outside through the inner glass part. On the straight fin tube and the inner glass part, the external radiation heat loss of the straight fin tube part is reduced, so that the solar vacuum heat collector tube can optimize the light and heat collection effect.

2. The side corresponding to the heat shield and the outer glass tube is a heat-absorbing surface with a selective absorption coating. The temperature of the heat shield will rise when the sun irradiates directly, and the inner glass part covered by the heat shield The radiation heat exchange with the heat shield will be greatly reduced, thereby indirectly reducing the external radiation heat loss.

3. The outer surface of the fins and straight-finned tubes can be coated with a spectrally selective coating. By increasing the solar light absorption area, the convective heat transfer intensity between the fluid and the heat-absorbing surface of the straight-finned tubes is enhanced, and the solar radiation light-to-heat conversion efficiency is improved. The fluid (water) is forced to flow in the straight rib tube, the flow rate is fast, the temperature is low, it is not easy to scale, and it is easy to clean even if scale is formed.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the main cross-sectional view of the structure of vacuum heat collector 1 of the present utility model;

Fig. 3 is a cross-sectional view at A-A in Fig. 2;

Fig. 4 is a schematic diagram of the solar light propagation path of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

As shown in Figure 1, a straight-fin tube-finned trough concentrating vacuum solar collector includes a vacuum collector 1 and a trough concentrator 2, and the trough concentrator 2 adopts the The reflective mirror surface of the trough for light reflection and collection is set, and the inner surface is provided with an evaporated aluminum film to enhance the reflectivity. The vacuum heat collector 1 is arranged at the concentrating position of the trough concentrator 2; the vacuum heat collector 1 and the trough concentrator 2 are fixedly installed on a rotating device (not shown in the figure) tracking the position of the sun, The collector tracks the sun for maximum heat collection.

The trough concentrator is used as a reflective material with metal aluminum, aluminum and metal coating. Silver and copper have good reflective properties, but the surface is easily oxidized. Among the metals, aluminum is the best metal to directly reflect sunlight. The reflectivity of the evaporated aluminum film can reach 0.95, which is slightly lower than 0.97 of the silver-plated film. When a metal plate is chosen as a reflector, it doubles as a substrate. When the reflective material is aluminum, the protective film of the surface mirror can be anodized film.

As shown in Figures 1 and 2, the vacuum heat collector 1 includes a straight-through glass vacuum sleeve 101, and the straight-through glass vacuum sleeve 101 includes an outer glass tube 1011, an inner glass tube 1012, and the outer glass tube 1011 and A vacuum layer 1013 is formed between the inner glass tubes 1012. The inner glass tube 1012 is equipped with a straight rib tube 102 for the passage of heat medium fluid. The straight rib tube 102 is fixed on the axis of the inner glass tube 1012 by a spring 103, and A sealing ring 104 is installed at both ends of the inner glass tube 1012 .

As shown in Figure 3, two arc-shaped heat shields 105 are arranged in the vacuum layer 1013, and the heat shields 105 are respectively along two diameters of the diameter of the outer glass tube 1011 perpendicular to the mirror symmetry line of the trough concentrator 2. The end is extended toward the inner side of the outer glass tube 1011 and the mirror surface of the trough concentrator 2; the central angle of the inner glass tube 1012 covered by the two heat shields 105 is 60°, and the heat shield 105 is directly irradiated by the sun. And it can ensure that the sunlight propagation path reflected by the trough concentrator 2 is not blocked. The heat shield 105 is made of aluminum alloy, the side of the heat shield 105 corresponding to the inner glass tube 1012 is a reflective surface with high reflectivity, and the side corresponding to the outer glass tube 1011 is provided with a selective absorbing coating heat-absorbing surface. The reflective surface is provided with a reflective layer with high reflectivity and low emissivity characteristics, which can reflect the reflected spot of the trough concentrator 2 to the back of the inner glass tube 1012 for a second time, and can improve the reception of the vacuum heat collector 1. The problem of uneven heat flux. And the portion of the inner glass tube 1012 covered by the heat shield 105 reflects most of the externally radiated heat back to the inner glass tube 1012, reducing heat loss.

The heat-absorbing surface of the heat shield 105 is provided with a selective absorption coating with high absorptivity and low emissivity in the solar radiation band, the temperature of the heat shield will rise when the sun irradiates directly, and the inner layer covered by the heat shield As the temperature difference between the glass tube 1012 and the heat shield 105 decreases, the radiation heat transfer will be greatly reduced, thereby indirectly reducing the external radiation heat loss of the inner glass tube 1012 .

Therefore, the heat insulation board 105 is added. Although the direct solar radiation rays that can be received by part of the inner layer glass tube 1012 are blocked, the heat absorption of the reduced inner layer glass tube 1012 is very little. Because the utility model increases the sunlight absorption area, the fin The outer surface of the sheet 106 and the straight-finned tube 102 can be plated with a spectrally selective coating to improve the solar radiation light-to-heat conversion efficiency. The radiant heat loss reduced by the thermal plate 105 is greater than the direct solar radiant heat that the inner layer glass tube 1012 part covered by the thermal insulation plate 105 can obtain.

Two fins 106 are installed on the outside of the straight ribbed tube 102, and the two fins 106 are arranged along the radial direction of the straight ribbed tube 102. The angle between the two fins 106 is 120°, and the angle subdivision line and the groove The direction of the mirror surface of the trough-type concentrator 2 is consistent, and coincides with the symmetry line of the arc surface of the trough-type concentrator 2. The vacuum layer 1013 can eliminate convective heat loss of the fins 106 . The material of the fins 106 is copper or aluminum, the thickness is 0.08mm-1mm, and the length is 100mm shorter than that of the inner glass tube 1012 . Both the fins 106 and the outer surfaces of the straight-finned tubes 102 are coated with a spectrally selective coating, which enhances the convective heat transfer intensity between the heat medium fluid and the heat-absorbing surface of the straight-finned tubes 102 by increasing the solar light absorption area, and improves the solar radiation. Light-to-heat conversion efficiency. The heat medium fluid is forced to flow in the straight-finned tube 102, the flow velocity is fast, the temperature is low, it is not easy to scale, and even if scale is formed, it is easy to clean.

In the application of the trough-type concentrating solar vacuum collector in the actual solar thermal power generation system engineering, with the constant change of the sun's altitude angle, the application of the trough-type concentrating solar collector needs to track the sun to achieve the maximum heat collection effect. According to the above-mentioned requirements, the direct sunlight will be parallel to the bisector of the two fins 106 angles of 120°, and the heat shield 105 will always be directly irradiated against the sun, and can ensure that the sun reflected by the trough concentrator 2 is not blocked. The light propagation path, so the integrated tracking method of the trough concentrator 2 and the vacuum collector is required, that is, the trough concentrator 2 and the vacuum collector tube 1 are fixed together to rotate and track the sun. This integrated tracking method is durable and convenient. The tracking device facility has a simple structure and is easy to manufacture.

In addition, the trough concentrator 2 of the present invention can also be equipped with a specially designed reflector surface, and reflector surfaces with different radians are provided at both ends of the original parabolic reflector, so that the secondary reflection effect of the heat shield 105 is better.

The described embodiments are only some of the embodiments of the present utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Claims (7)

1. A straight rib tube finned trough concentrating vacuum solar heat collector is characterized in that it comprises a vacuum heat collector and a trough concentrator, and the trough concentrator adopts a method capable of reflecting and gathering sunlight The trough reflector surface is set, and the vacuum heat collector is set at the light-gathering position of the trough concentrator; The vacuum heat collector includes a straight-through glass vacuum sleeve, and the straight-through glass vacuum sleeve includes an outer glass tube and an inner glass tube. A vacuum layer is formed between the outer glass tube and the inner glass tube, and the inner glass tube The middle wear is equipped with a straight rib tube for the passage of heat medium fluid. The straight rib tube is fixed on the axis of the inner glass tube by a spring, and a sealing ring is installed at both ends of the inner glass tube; two arc-shaped tubes are arranged in the vacuum layer. The heat insulation board extends relatively along the two ends of the diameter of the outer glass tube perpendicular to the symmetrical line of the trough-type concentrator mirror to the inner side of the outer layer glass tube and the direction of the mirror surface of the trough-type concentrator; Two fins are installed on the outside of the straight rib tube, and the two fins are arranged along the radial direction of the straight rib tube. The mirror symmetry lines of the optics coincide. 2. The straight-fin tube-finned trough concentrating vacuum solar heat collector according to claim 1, wherein the central angle of the inner layer glass tube covered by the two heat shields is 60°; There is an angle of 120° between the two fins. 3. The straight-fin tube-finned trough concentrator vacuum solar collector according to claim 1, wherein the vacuum collector and the trough concentrator are fixedly installed on a rotating device that tracks the position of the sun superior. 4. According to any one of claims 1-3, the straight-finned tube-finned trough concentrating vacuum solar heat collector is characterized in that, the inner surface of the trough concentrator is provided with a vapor-depositing layer that enhances reflectivity. Aluminum film. 5. According to any one of claims 1-3, the straight-finned tube-finned trough concentrating vacuum solar heat collector is characterized in that the material of the fins is copper or aluminum, and the thickness is 0.08mm-1mm , the length is 100mm shorter than the inner glass tube. 6. According to any one of claims 1-3, the straight-fin tube-finned trough concentrating vacuum solar collector is characterized in that, the material of the heat shield is aluminum alloy, and the heat shield and the inner glass The side corresponding to the tube is a reflective surface with high reflectivity, and the side corresponding to the outer glass tube is a heat-absorbing surface provided with a selective absorbing coating. 7. According to any one of claims 1-3, the straight-finned tube-finned trough concentrating vacuum solar heat collector is characterized in that the outer surfaces of the fins and the straight-finned tubes are coated with spectrally selective coatings. Floor.