CN201463295U - Medium temperature solar collector - Google Patents

Abstract

The utility model discloses a medium-temperature solar heat collector. This utility model medium-temperature solar heat collector is provided with a header box for connecting all-glass vacuum solar heat collector tube groups and headers in the frame mainly composed of its frame and bottom plate, and on the opposite side of the header box, A tailstock and a tailstock for fixing the heat collecting tubes are provided, a reflecting plate is provided on the bottom plate, and a transparent transparent plate encapsulating the all-glass vacuum solar heat collecting tube group with the frame and the bottom plate is provided on the light-receiving surface of the heat collector. The cover plate; the U-shaped tube matched with the heat collecting tube is plated with anti-oxidation coating or adopts a metal with strong anti-oxidation ability. The medium-temperature solar heat collector based on the technical solution of the utility model has low cost and high working temperature.

Description

Medium temperature solar collector

(1) Technical field

The utility model relates to a medium-temperature solar heat collector, which adopts all-glass vacuum solar heat collecting tubes as heat collecting elements, and puts one or two groups of heat collecting tubes together through headers, tailstocks and tailstocks within prefabricated borders.

(2) Background technology

It is known that the heat collection efficiency of solar collectors using all-glass vacuum solar collector tubes as heat collecting elements is low, and its working temperature is 40°C to 80°C, which belongs to the low temperature zone, which is much lower than that of metal vacuum heat collector tubes, although the cost is relatively low , but its application range is relatively narrow, mainly used to provide domestic hot water.

In principle, the all-glass vacuum solar collector is based on the all-glass vacuum solar collector tube as the heat collecting element, which is assembled in the prefabricated rectangular frame through the header, tailstock and tailstock. Among them, the heat collecting tube is used to enrich the heat, and there is a U-shaped tube inside it, also called a U-shaped regulator, which is fixed in the heat collecting tube through the heat conducting sheet, and the U-shaped tube is connected with a circulating medium for exchanging the enriched heat to the tank. At present, in order to improve the heat collection efficiency of solar heat collectors, those skilled in the art all use the method of improving the heat collecting tube, specifically, coating the inner glass tube of the said all-glass vacuum solar heat collecting tube to absorb Coatings have been used in this way for a long time. For example, the Al-N/Al gradient film disclosed in Chinese patent CN85100142 is widely used in China. The advantage of this coating is that it uses a single Al target DC magnetron sputtering coating , which simplifies the structure of the sputtering system, improves the sputtering efficiency, shortens the production cycle, and lowers the cost. 100°C, it cannot work for a long time under the condition of higher than 100°C.

China Intellectual Property Office No. 200810224525.8 utility model patent application discloses a medium-temperature glass-metal structure solar vacuum heat collector tube, which improves the vacuum life of the all-glass vacuum solar heat collector tube after the long-term working temperature is extended to above 140°C. The heat collection using this kind of medium-temperature heat collector is defined as a medium-temperature heat collector, but at present, the medium-temperature heat collector is an improvement of the heat collector on the basis of the existing heat collector. After the working temperature reaches a certain level, every It is difficult to increase by one degree, and the cost of a single-tube heat collector is very high.

(3) Contents of the invention

Therefore, in order to overcome the above-mentioned defects of the prior art, the utility model provides a medium-temperature solar heat collector mainly based on the improved structure of the heat collector, which has low cost and high working temperature.

The utility model adopts the following technical solutions:

This utility model medium-temperature solar heat collector is provided with a header box for connecting all-glass vacuum solar heat collector tube groups and headers in the frame mainly composed of its frame and bottom plate, and on the opposite side of the header box, A tailstock and a tailstock for fixing the heat collecting tubes are provided, a reflecting plate is provided on the bottom plate, and a transparent transparent plate encapsulating the all-glass vacuum solar heat collecting tube group with the frame and the bottom plate is provided on the light-receiving surface of the heat collector. The cover plate; the U-shaped tube matched with the heat collecting tube is plated with anti-oxidation coating or adopts a metal with strong anti-oxidation ability.

The medium-temperature solar heat collector according to the technical solution of the utility model is different from the existing heat collector which mainly relies on improving the heat collection efficiency of the heat collection tube, and further improves the structure of the heat collection itself. Of course, it does not rule out the use of a new type of heat collection tube. .Firstly, reflectors are used to increase the energy received by the heat collecting tubes from solar radiation, that is to say, the heat collecting tubes can not only receive the radiant energy of sunlight directly irradiated on them, but also receive the radiation reflected from the reflectors between the heat collecting tubes Even if the flat reflector is used, the heat collection efficiency can be increased by about 5%. In addition, the cover plate structure can not only protect the heat collection tube, but also prevent dust from covering the heat collection tube and affecting the heat collection efficiency. , but also prevent other garbage from entering the collector, and can also prevent heat loss and play a certain role in heat preservation. On the other hand, the existence of the transparent cover makes a greenhouse inside the collector, and the existence of the greenhouse effect can reduce heat loss. losses and improve heat collection efficiency.

Due to the above measures, the heat collection efficiency of the heat collector is improved. Therefore, the U-shaped pipe matched with the heat collection pipe is coated with an anti-oxidation coating to improve its oxidation resistance under high temperature conditions and prolong its use. life.

In the above-mentioned medium-temperature solar heat collector, the reflector is a plane reflector or a reflective arc plate with a strip-shaped reflective concave surface corresponding to each heat collecting tube, and the reflected light of the reflective arc plate is projected on the corresponding heat collecting tube.

Considering that the reflection plate is located under the heat collecting tube, the existence of the cover plate can overcome the defect that dust is difficult to clean the reflection plate from polluting it.

Another solution of the reflective plate is that it includes a reflective unit corresponding to each heat collecting tube, and the light reflecting unit includes two concave parts connected by a connecting part located directly under the corresponding heat collecting tube.

The section arc of the concave portion is an involute or compound parabola of the corresponding heat collecting tube section circle.

The projected area of the two arc-shaped parts on the heat collecting tube is equal to the surface area of the used heat collecting tube.

The opening width of the reflector is 115-145mm, and the opening width here is aimed at the outer diameter of the inner tube of the heat collecting tube of 37mm; when the outer diameter of the inner tube of the heat collecting tube is other sizes, the opening width is different, and those skilled in the art can use it accordingly Make adjustments.

The reflective mirror surface of the curved surface is a highly reflective mirror surface.

The heat collector is a vertical single-row structure, a horizontal single-row structure or a horizontal double-row structure; the assembly of the cover plate and the frame is provided with a sealing strip; the space in the header box is filled with thermal insulation materials except for the collection parts; The transparent cover has an anti-reflection film.

The heat collecting tube adopts a medium-temperature heat collecting tube.

(4) Description of drawings

The technical scheme of the utility model is further described below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the utility model, wherein:

Fig. 1 is a bottom sectional view of an embodiment of a medium-temperature solar heat collector of the present invention.

Fig. 2 is a top view structural diagram of an embodiment of a medium-temperature solar heat collector of the present invention.

Fig. 3 is a structural schematic diagram of the reflective monomer in the reflector in the embodiment of the medium-temperature solar heat collector of the present invention.

Fig. 4 is a schematic diagram of a medium-temperature solar collector with a horizontal single-row structure in an embodiment of the utility model.

Fig. 5 is a schematic diagram of a medium-temperature solar collector with a horizontal double-row structure in an embodiment of the utility model.

Fig. 6 is an efficiency curve diagram of a medium-temperature heat collector in an embodiment of the utility model.

Fig. 7 is a schematic diagram of light rays of a two-dimensional compound parabolic concentrator with a cylindrical absorber.

In the figure: 1. Connector, 2. Header, 3. Cover plate, 4. Sealing strip, 5. Insulation layer, 6. Frame, 7. Header, 8. Tailstock, 9. Tailstock, 10. Collector Heater, 11, heat conducting sheet, 12, reflection plate, 13, sealing ring, 14, U-shaped pipe, 15, connection part, 16, concave part, 17, assembly part.

(5) Specific implementation methods

The technical scheme of the utility model is described as an example below:

Accompanying drawing 1 of the description shows a kind of medium-temperature solar heat collector with a vertical single-row structure. Taking it as an example, the frame 6 and the bottom plate of this medium-temperature solar heat collector are mainly provided with a set for connecting all glass Vacuum solar heat collection tube group, header 7 with header 2, and on the opposite side of the header, a tailstock 9 and its tailstock 8 for fixing the heat collection tube 10 are provided, and a reflector is provided on the bottom plate plate 12, and on the light-receiving surface of the heat collector, a transparent cover plate 3 that encapsulates the all-glass vacuum solar heat collection tube group with the frame and the bottom plate; the U-shaped tube 14 that matches the heat collection tube is coated with anti- Oxidation coating or metal with strong oxidation resistance.

Said metal with high anti-oxidation ability can be metals such as copper, copper-nickel alloy or stainless steel; said anti-oxidation coating can be made of galvanized, nickel, chromium, aluminum or other anti-oxidation materials. As for which solution to adopt, the main consideration is cost. Although there are many metals with strong oxidation resistance, stainless steel is relatively low in cost and has good machinability. As for the anti-oxidation coating, the requirements for satisfying the machinability of the base material of the U-shaped tube are relatively low, and the range of material selection for the U-shaped tube can be expanded.

If the reflector is a plane reflector or a reflective arc plate with a strip-shaped reflective concave surface corresponding to each heat collecting tube, the reflected light of the reflective arc plate is projected on the corresponding heat collecting tube. The reflective arc plate can improve the heat collection efficiency by 8-9%.

Preferably, this solution tends to adopt that the reflective plate includes a reflective unit corresponding to each heat collecting tube, and the light reflecting unit includes two concave surfaces 16 connected by a connecting portion 15 located directly under the corresponding heat collecting tube. Compared with the above two reflectors, this kind of reflector has higher efficiency and can increase the efficiency of the collector by about 15%. According to the test, the working temperature of the medium-temperature solar collector with the above structure is 80 ° C ~ 160 ° C, instantaneous The efficiency intercept reaches above 0.66, and when working at 120°C, the efficiency intercept reaches above 0.49.

In order to improve the heat collection efficiency in the heat collection period more effectively, the cross-sectional arc of the concave portion is the involute or compound parabola of the corresponding heat collection tube section circle; the projected area of the two arc portions on the heat collection tube is equal to the used collector The surface area of the heat pipe.

The reflective mirror surface of the curved surface adopts a highly reflective mirror surface, where the high reflective mirror surface refers to a reflective mirror surface with a mirror reflectivity greater than 0.70, and the reflectivity is high. In order to improve the reflection efficiency of the curved surface, the preferred reflectance of this solution is higher than 0.80 reflective mirror surface.

An embodiment based on the technical solution of the utility model adopts a composite parabolic reflector with an opening width of 115mm, a U-shaped tube coated with a metal coating, and a medium-temperature solar collector with a medium-temperature all-glass vacuum solar collector tube. Accordingly, the specification is attached Figure 6 shows the efficiency curve for a maximum operating temperature of 120°C.

It can be seen from the curve that the instantaneous efficiency intercept of the solar collector is 0.660, and the efficiency when the operating temperature is 120°C is 0.491.

Another embodiment based on the technical solution of the present utility model adopts a compound parabolic reflector with an opening width of 135mm, a U-shaped tube coated with a metal coating, a medium-temperature solar collector with a glass cover plate, and a medium-temperature all-glass vacuum solar collector tube. , the instantaneous efficiency intercept is 0.641, and the efficiency when the operating temperature is 120°C is 0.505.

Based on the technical solution of the utility model, in one embodiment, a compound parabolic reflector with an opening width of 145 mm, a U-shaped tube with a metal coating, a glass cover plate, and a medium-temperature solar collector with a medium-temperature all-glass vacuum solar collector tube are adopted. , the instantaneous efficiency intercept is 0.630, and the efficiency when the operating temperature is 120°C is 0.518.

Just as the cross-sectional curve of the reflecting plate above adopts the involute or compound parabola corresponding to the section circle of the heat collecting tube, those skilled in the art can also use other cross-sectional curves of the reflecting plate to increase the light-receiving area and intensity of the heat collecting tube.

Referring to Figure 7 of the specification, it shows the principle of light from a two-dimensional compound parabolic concentrator of a cylindrical absorber. The inner circle of the above-mentioned involute is the inner circle of the vacuum tube collector, that is, the surface of the absorber. The coordinate system yoz shown in Figure 7 is established with the y-axis as the axis of symmetry, and θ is the angle between the line connecting the Q point to the origin and the negative semi-axis of the y-axis. The radius of the inner diameter of the heat absorber is r, and the distance from point Q to P on the heat absorber is t. For any point P on the reflective surface, its coordinates are:

x=rsinθ-tcosθ

y=-rcosθ-tsinθ

Wherein, when _θ≤θi +π/2, t=rθ;

When π/2+θ _i ≤θ≤3π/2-θ _i , $t=\frac{r[(\mathrm{\θ}+{\mathrm{\θ}}_i+\mathrm{\π}/2)-\cos (\mathrm{\θ}-{\mathrm{\θ}}_i)]}{[1+\sin (\mathrm{\θ}-{\mathrm{\θ}}_i)]}$

θ is the angle value of polar coordinates, θ _i is the half-acceptance angle, and t is the polar radius. The above formula is used as the basis for the design of the compound parabolic reflector.

The heat collector can adopt a vertical single-row structure, a horizontal single-row structure or a horizontal double-row structure according to practical applications.

In order to improve the sealing level between the heat collector tube group and the outside world, a sealing strip is provided at the assembling place between the cover plate and the frame.

In order to improve the thermal insulation effect of the heat collector, the space in the header except the collection parts is filled with thermal insulation material.

The heat collecting tube adopts a new type of heat collecting tube, which is a medium-temperature heat collecting tube, which can greatly improve heat collecting efficiency and service life.

In order to improve the transmittance of sunlight, the cover plate is provided with an anti-reflection film.

Since the working temperature of the heat collector based on this scheme has been greatly improved compared with the existing heat collector, its application is not limited to providing domestic hot water, and its maximum working temperature has reached the temperature required for power generation, which greatly expands its scope of application.

Claims (9)

1. temperature solar heat collector in a kind, at its frame (6) and base plate is to be provided with the header (7) that collects the complete glass vacuum sun thermal-collecting tube group, has union pipe (2) in order to join in the main framework that constitutes, and at the heteropleural of header, be provided with the tailstock (9) and the tailstock (8) that are used for fixing thermal-collecting tube (10), it is characterized in that: on described base plate, be provided with reflecting plate (12), and be provided with the transparent cover plate (3) that all glass vacuum heat collection tube of solar energy group is encapsulated with described frame and base plate at the heat collector sensitive surface; The U type pipe (14) that is complementary with described thermal-collecting tube is coated with ORC or adopts the strong metal of oxidation resistance.

2. temperature solar heat collector in according to claim 1, it is characterized in that: described reflecting plate is the reflective arc plate of plane reflection plate or the reflective concave surface that all has a bar shaped corresponding to every thermal-collecting tube, and the reverberation of this reflective arc plate is incident upon on the respective episode heat pipe.

3. temperature solar heat collector in according to claim 1, it is characterized in that: described reflecting plate comprises the reflecting unit corresponding to every thermal-collecting tube, and this reflecting unit comprises two the concave surface portions (16) that connect by the connecting portion that is positioned at the positive bottom of respective episode heat pipe.

4. temperature solar heat collector in according to claim 3 is characterized in that: the cross section camber line of described concave surface portion is the involute or the compound parabolic of respective episode heat pipe cross section circle.

5. temperature solar heat collector in according to claim 4, it is characterized in that: described two projected areas of cambered surface portion on thermal-collecting tube equal the surface area of used thermal-collecting tube.

6. temperature solar heat collector in according to claim 5, it is characterized in that: the A/F of described reflecting plate is 115～145mm.

7. temperature solar heat collector in according to claim 5 is characterized in that: the mirror surface of described cambered surface portion is the high reflection mirror face.

8. temperature solar heat collector in according to claim 1 is characterized in that: this heat collector is perpendicular single row configuration, horizontal single row configuration or horizontal two-row structure; Described cover plate and frame assembling place are provided with sealing strip; Space in the described header except that connection collection parts is filled with insulation material; Described transparent cover plate has anti-reflection film.

9. temperature solar heat collector in according to claim 1 is characterized in that: warm thermal-collecting tube during described thermal-collecting tube adopts.

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