CN106091416A - A kind of interpolation three fin straight ribbed pipe vacuum tube collector - Google Patents

Abstract

The invention discloses a vacuum tube heat collector inserted with three fins straight rib tubes, comprising a glass vacuum sleeve, characterized in that a straight rib tube is arranged in the center of the glass vacuum sleeve; the two ends of the glass vacuum sleeve are There is a sealing ring, and the two ends of the straight rib tube pass through the sealing ring and are fixed by the sealing ring; there are three fins on the straight rib tube; the angle between the three fins is 120°, and one of the fins is vertical straight up. The present invention can eliminate the shortcoming (cosine efficiency) of two-finned straight tubes or two-finned U-shaped tubes with relatively small sunlight effective absorption area (cosine efficiency) when the sun altitude angle is relatively low, ensuring that the sunlight effective absorption area is relatively constant at any time, and improves Thermal efficiency and operational stability of collectors. The three-fin straight-finned tube is relatively independent of the glass vacuum casing. While ensuring thermal efficiency, it is relatively convenient to install and maintain, and is convenient for engineering application and promotion.

Description

An Evacuated Tube Heat Collector with Inserted Three-Fin Straight Fin Tubes

technical field

The invention belongs to the technical field of heat energy utilization, and in particular relates to a vacuum tube heat collector inserted with three-fin straight fin 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. The use of solar collectors is flexible. It can be used alone to provide solar hot water, or it can be used together with air source heat pumps to form a solar assisted air source heat pump hot water system to provide hot water for hotels, hospitals, dormitories, factories, and communities.

Solar collectors are the key to solar water heating systems. Judging from the current market promotion, although vacuum tube collectors have high efficiency, they are prone to fouling and poor pressure resistance. They can only be used in small systems such as household solar water heaters. , Its application in engineering is not as popular as flat plate collectors.

The glass vacuum tube collector has an important application prospect because it eliminates the convective heat dissipation loss between the solar heat absorbing surface and the outside air, and has high thermal efficiency. However, vacuum tube collectors have the disadvantages of easy fouling, large heat sink, and poor pressure resistance, which are limited in large-scale applications.

Improved vacuum tube collectors, such as U-tube vacuum tube collectors inserted, heat tube vacuum tube collectors inserted, or vacuum tube collectors filled with phase-change energy storage materials, etc., all have complex structures, low thermal efficiency, or Inadequacies such as expensive price, difficult promotion, few practical applications.

CN104016432A discloses a plug-in copper water heat pipe vacuum solar water distiller, which includes a solar vacuum tube heat collector main body and an insulated water tank. The solar vacuum tube heat collector main body includes a heat pipe heat collecting element, several heat transfer sleeves and supports; The components include vacuum heat collecting tubes and plug-in copper water heat pipes, which are characterized in that the closed end of the heat transfer sleeve extends into a horizontally arranged evaporation flow channel; the cold end of the copper water heat pipe is connected with the heat transfer sleeve; the evaporation flow The end of the channel is connected to a concentrated water discharge pipe through a concentrated water valve; the insulated water tank contains a built-in condensing pipe, and the inlet and outlet of the built-in condensing pipe are respectively connected with the evaporation flow channel and a distilled water connection pipe.

CN101699191A discloses a combined curved surface concentrating vacuum tube heat collection integrally encapsulated solar heat collector, which is composed of a combined curved surface concentrator, a vacuum tube heat collector, an adjustable tracker, and a packaging shell. After the sunlight enters the combined curved surface concentrator through the transparent glass cover plate, it is reflected by its inner surface and collected on the vacuum tube collector, and is absorbed by the vacuum tube collector to generate high-temperature heat energy, which is then conducted by the vacuum tube collector. The heat-conducting working fluid is delivered to the user.

The current types of solar collectors are flat-plate solar collectors, all-glass vacuum tube collectors, U-tube vacuum tube collectors, heat pipe vacuum tube collectors and direct-flow vacuum tube collectors. Each type of collector has certain advantages, but also has obvious disadvantages:

1) Flat-plate solar collectors are under pressure and are not easy to scale, but the heat-absorbing convective heat dissipation loss is large and the thermal efficiency is relatively low;

2) The all-glass vacuum tube collector has high thermal efficiency, but it cannot operate under pressure, it is easy to freeze and crack, and it is easy to scale, so it is not suitable for use in large-area solar water heating systems. It is mostly used as a heat collecting component of household solar water heaters.

3) The U-tube vacuum tube collector is under pressure and is not easy to scale, but the fluid is easy to short circuit. In addition, the heat-absorbing surface is mostly flat, and the absorption efficiency of sunlight on the heat-absorbing surface is not high.

4) The heat pipe vacuum tube collector is under pressure, not easy to scale, and has relatively high thermal efficiency, but the price is relatively expensive, and the performance of the heat pipe is easy to decay and age.

5) The direct-flow vacuum tube collector is under pressure, is not easy to scale, and has relatively high thermal efficiency, but the absorption efficiency of sunlight on the heat-absorbing surface is not high.

Aiming at the disadvantages of low thermal efficiency, easy fouling, or relatively high cost, the present invention proposes a straight-line three-fin interpolated heat-absorbing surface with high solar absorption efficiency, pressure resistance, and difficult structure, which can be used in large-area solar water heating systems. Finned tube evacuated tube collector scheme. Provide technical support for the promotion and engineering application of vacuum tube solar collectors.

Technical solutions:

In order to solve the problems existing in the current solar heat collector, the invention discloses a vacuum tube heat collector with three-finned straight fin tubes inserted.

The present invention is realized by adopting the following technical solutions:

A vacuum tube heat collector with three-finned straight-finned tubes inserted, comprising a glass vacuum sleeve, a straight-finned tube is provided at the center of the glass vacuum sleeve; sealing rings are provided at both ends of the glass vacuum sleeve, and the straight-finned tube The two ends of the tube pass through the sealing ring and are fixed by the sealing ring; there are three fins on the straight rib tube; the angle between two of the three fins is 120°, and one of the fins is vertically upward.

As a further improvement, the straight-finned pipe is a copper straight-finned pipe or an aluminum straight-finned pipe.

As a further improvement, the thickness of the fins is 2-3 mm, the height is 20-30 mm, and the length of the fins is 80-120 mm shorter than that of vacuum glass.

As a further improvement, the straight rib tube and the fins are provided with a spectrally selective coating.

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

1) The three fins of the three-fin straight-finned tube are evenly distributed along the circumferential direction of the circular tube, which can eliminate the comparison of the effective absorption area of sunlight between the two-finned straight tube or the two-finned U-shaped tube when the solar altitude angle is relatively low. The small deficiency (cosine efficiency) ensures that the effective absorption area of sunlight at any time is relatively constant, and improves the thermal efficiency and operational stability of the collector.

2) The three-fin straight-finned tube and the glass vacuum sleeve are relatively independent. While ensuring the thermal efficiency, the installation and maintenance are relatively convenient, and it is convenient for engineering application and promotion.

Description of drawings

Fig. 1 is the structural representation of embodiment 1;

Fig. 2 is A-A sectional view in Fig. 1;

Fig. 3 is the B-B sectional view among Fig. 1;

Figure 4 is a schematic diagram of heat absorption efficiency.

detailed description:

The present invention will be described in detail or described below by way of examples, rather than limiting the present invention.

Example 1:

As shown in Figure 1, a vacuum tube collector with three-finned straight-finned tubes inserted includes a glass vacuum sleeve, and a straight-finned tube is arranged at the center of the glass vacuum sleeve; two ends of the glass vacuum sleeve are provided with Sealing ring, the two ends of the straight ribbed tube pass through the sealing ring and are fixed by the sealing ring; there are three fins on the straight ribbed tube; the angle between the three fins is 120°, and one of the fins is vertically upward . The straight rib tube is made of copper or aluminum. One end of the straight-finned tube is the fluid inlet and the other end is the fluid outlet. The thickness of the fins is 2-3 mm, the height is 20-30 mm, and the length of the fins is 80-120 mm shorter than that of the vacuum glass. Spectrum selective coatings are provided on the straight rib tubes and fins to improve sunlight absorption efficiency and reduce their own infrared radiation heat loss. In order to improve the solar heat conversion efficiency, the thermal efficiency of the collector is improved.

As shown in the fin distribution in Figure 2, the fin 1 is arranged along the vertical direction, the fin 2 is located on the left side, and the fin 3 is located on the right side. When the sun is on the right side, the fins 1 and 3 absorb sunlight and turn it into a heat source, heating the fluid flowing through the tube. When the sun is on the left side, fins 1 and 2 absorb sunlight and turn it into a heat source, heating the fluid flowing through the tube. When the sun is in the middle position, the fins 1, 2 and 3 absorb the sun at the same time and become heat sources to heat the fluid flowing through the tube.

The inner and outer layers of glass form a glass casing, and the middle is evacuated to eliminate the convective heat dissipation loss of the heat-absorbing fins. As shown in Figure 3, the sealing ring forms a closed cavity between the three-fin straight-finned tube and the inner glass space, preventing the air in the closed cavity from absorbing the heat of the finned tube and dissipating it to the surrounding environment, reducing the thermal efficiency of the heat-absorbing surface. At the same time, the sealing ring also plays a role in supporting and fixing the straight rib tube.

As shown in Figure 4, my country is located in the northern hemisphere, and solar collectors are generally arranged due south, with an inclination angle of about 20° to the horizontal plane. Due to the movement characteristics of the sun rising in the east and setting in the west, the sun's altitude angle is relatively low in the morning and afternoon. At this time, the cosine effect of the two-finned straight-finned tube on the plane is large, and the effective heat absorption area of the heat-absorbing plate is small, and the thermal efficiency of the system is low. , as shown in Figure 4(a) (only draw the case where the sunrise sun elevation angle is relatively small, and the sunset case is similar). Under the same vacuum glass tube diameter, if a three-fin straight-finned tube is used, the cosine effect of the heat-absorbing surface is relatively weak regardless of the sun's altitude angle. Compared with Figure 4(a) and Figure 4(b), the sunlight is effective It can be seen from the absorption surface that the three-fin straight-finned tube has a large area of effective sunlight absorption surface and high thermal efficiency, as shown in Figure 4(b) (only the sunrise and sun altitude angles are relatively small, and the sunset situation is similar).

Claims (4)

1. a kind of three-fin straight-fin tube vacuum tube heat collector inserted, comprising a glass vacuum sleeve, is characterized in that, the central position in the glass vacuum sleeve is provided with a straight rib tube; the two ends of the glass vacuum sleeve are provided with Sealing ring, the two ends of the straight ribbed tube pass through the sealing ring and are fixed by the sealing ring; there are three fins on the straight ribbed tube; the angle between the three fins is 120°, and one of the fins is vertically upward . 2. A vacuum tube heat collector with three-finned straight-finned tubes inserted as claimed in claim 1, characterized in that the straight-finned tubes and fins are made of red copper or aluminum. 3. A vacuum tube collector with three-finned straight fins inserted as claimed in claim 1, characterized in that the thickness of the fins is 2-3 mm, the height is 20-30 mm, and the length of the fins is longer than that of vacuum tubes. The length of the glass is 80-120mm. 4. A vacuum tube heat collector with three-finned straight-finned tubes inserted as claimed in claim 1, characterized in that said straight-finned tubes and fins are provided with a spectrally selective coating.