CN101046331B - Comb cross-section spiral channel solar heat collector tube - Google Patents

Abstract

The solar heat collecting pipe with comb-shaped cross section and spiral flow channel has huge transparent vacuum pipe with vacuum glass pipe as outer layer, inner layer and expanded flexible arc; inside spiral metal flow channel with comb-shaped cross section, outer coating and blower or pump forced flowing work medium gas or liquid, inside vacuum glass sleeve and vacuum disc with reflecting aluminum-plastic film, central shaft for hoisting with heat insulating cap, end cap and hoop, and other parts. The huge very long solar heat collecting pipe can provide great heat resource.

Description

Comb cross-section spiral channel solar heat collector tube

technical field

The invention belongs to the technical field of solar energy utilization and relates to a large-energy heating device, in particular to a comb-shaped cross-section spiral channel solar heat collection tube.

Background technique

The heating temperature of the glass vacuum heat collecting tubes in the prior art is relatively low, and the energy is relatively small, and there are the following problems:

1. Through thermal radiation, it is a better design for the spectral absorption layer heat on the metal tube in the vacuum tube to be conducted to the working medium. However, to provide high-energy heat energy, since the increase of the heating area of the metal tube is smaller than the increase of its volume: the volume increases, the heat capacity of the working medium is also large, and the efficiency drops sharply, which is a contradiction; 2. The vacuum tube is equipped with a metal tube with fins In the design of conventional materials, the heating area is increased by the fins, but a large energy heat source is to be provided, and the thermal efficiency is improved by the fins, which will show the following contradictions. The bigger the fins are, the longer the path of heat conduction to the working fluid is, and the more the efficiency drops. The reason is that there is no working medium in the fins, and the fins also need to store heat and radiate heat. 3. Use a glass vacuum tube with a larger diameter to pass water directly, which not only saves the water tank but also increases the light-receiving area. Deposition and freezing explosion. The temperature difference between the inner and outer layers is large, and it is easy to burst due to cold and heat. Because the inner layer has a selective absorption layer, the temperature is higher, but glass is not a good heat conductor, and the thermal resistance is large, resulting in high emissivity of the heat collecting layer, so the radiation loss is also large.

Contents of the invention

The purpose of the present invention is to provide a high-energy solar energy utilization device for industry, agriculture and sunshine buildings, so the working medium is forced to flow through the comb-shaped cross-section spiral flow channel by the fan and the liquid pump, so as to facilitate high-efficiency heat exchange.

The technical solution of the present invention is to include a glass tube made of fully transparent glass, and a metal flow channel is arranged in the glass tube, and it is characterized in that: the glass tube is composed of inner and outer glass tubes with different diameters, One end of the inner and outer glass tubes is fused to form a ring mouth, and an interlayer is formed between the inner and outer glass tubes; the other end of the inner and outer glass tubes is made into an annular expansion deflection arc before welding , using the deflection of the glass to offset the expansion difference between the inner and outer glass tubes; the glass tube interlayer is evacuated; the metal flow channel is a spiral flow channel with a metal comb-shaped section, and the metal comb The surface of the helical channel with a cross-section is coated with a spectrally selective coating, and a working fluid is arranged in the helical channel with a metal comb-shaped section, and the working fluid is water, air, or an antifreeze liquid.

Butt one end of the annular mouths of the two glass tubes with each other.

The helix of the helical channel of the metal comb-shaped cross-section is a single-headed helix or a multi-headed helix, and an interval is provided between the helical flow channels of the metal comb-shaped cross-section of the single-ended helix, so as to maintain a certain helix angle and work Mass flow rate; there is no gap between the cross-sections of the metal comb-shaped cross-section of the multi-head spiral, which can maintain a large helix angle and increase the flow rate of the working fluid and the heating area.

The beneficial effect of the present invention is: utilize the advantage of low heat loss of glass vacuum tube, be equipped with metal comb-shaped cross-section spiral flow channel inside it, (parts 3 and 4 and Fig. 6 of Fig. 1), flow working medium in the flow channel. As far as the general spiral device is concerned, it already has a large surface area. Now the circular tube section is made into a comb-shaped section, so it has a large volume, and has the advantages of large heating area and conduction area. At the same time, it takes advantage of the high heat transfer efficiency of the metal flow channel and the selective film coating on its surface with high absorption ratio and low emissivity, so that the thermal resistance and heat capacity are small, and the thermal efficiency is extremely high.

Description of drawings

Fig. 1 is a structural diagram of the docking of the tails of two large vacuum glass tubes and the non-butting of the comb-shaped cross-section spiral flow channel.

Fig. 2 is part number 11 hoops of Fig. 1 (and bolts are all galvanized steel).

Fig. 3 is the part number 8 end cap (reinforced engineering plastics) of Fig. 1 .

Fig. 4 is the part number 12 vacuum disk (vacuum glass disk) of Fig. 1.

Fig. 5 is the part number 13 vacuum sleeve (vacuum glass cylinder) of Fig. 1.

Fig. 6 is item number 4 of Fig. 1, which is a cross-sectional view of a comb-shaped cross-section spiral flow channel.

Figure 7, Figure 8 and Figure 6 show the number of teeth in the comb-shaped cross-section of the comb-shaped spiral flow channel, which can be determined according to the diameter of the vacuum pipe; the larger the diameter of the vacuum pipe, the more teeth in the cross-section of the flow channel.

Fig. 9 is a schematic diagram of the manufacture of the expansion deflection arc in which item number 6 in Fig. 1 is.

Figure 10 shows that when the diameter of the glass vacuum tube is less than φ150mm, the spiral channel with trapezoidal section can be used.

Fig. 11 shows that when the glass vacuum tube diameter < φ80mm, an approximate triangular cross-section or spiral tube internal diameter < φ5mm can be used with a circular cross-section flow channel, (as shown in a and b of Fig. 11).

Detailed ways

The purpose of the present invention is to provide a high-energy solar energy utilization device for industry, agriculture and sunshine buildings. Therefore, the working medium is forced to flow through the comb-shaped cross-section spiral channel by the fan and the liquid pump, so as to facilitate high-efficiency heat exchange. The so-called working medium: air is used in drying industry; sea water is used in seawater desalination; tap water is used in sunshine building. The comb-shaped cross-section of the working fluid flow channel can withstand the tap water pressure and tolerate the advantages of freezing anti-expansion.

Manufacture of comb-shaped cross-section spiral flow channel: roll it with a thin metal skin (such as copper, aluminum or stainless steel) on a forming roll machine. There are corresponding comb-shaped cross-sectional concave-convex annular ribs on the circumferential direction of the roll (to make the roll devices mesh with each other, and the concave-convex ribs are transitioned with arcs, which is conducive to metal extension and stretching during the rolling process. According to The principle of the three-roller sheet rolling machine is to form a helical curved comb-shaped cross-section spiral channel shell (W in Figure 6) when it is rolled out, and then add a narrow and long metal sheet as the bottom layer (t in Figure 6). The h and h1 places are completed by rolling welding, and of course also available (Fig. 7 and Fig. 8) forms are pressed together with the swivel buckle structure.

Generally speaking: the larger the diameter of the vacuum tube, the more teeth it should have in the comb section, and vice versa. In the helix of a single thread in this design, there are five parallel lines, which is like a stave with five lines. Its cross-section is shown in Figure 6. The helix on the machine has a single thread and a multi-thread. In addition, the flow path in the vacuum tube can also be made into a multi-start thread with a large lead.

Winding of the comb-shaped cross-section spiral flow channel: ① First, two layers of heat-resistant aluminum-plastic composite film 5 are wound (and partially bonded) on the outer cylindrical surface of the vacuum sleeve (13 and 5 in Fig. Two functions: (1) The reflective layer is all outward, reducing the heat radiation of the working medium: ② Make the comb-shaped cross-section spiral flow channel easy to wrap around the outer cylindrical surface of the vacuum sleeve. The vacuum sleeve 13 is a glass vacuum cylinder (as shown in Figure 5). When winding, it must be wound on the outer cylindrical surface of the vacuum sleeve according to the right-handed helical rule, and there must be no gap in the middle. Wrap around until the outer cylindrical surface of the entire vacuum sleeve. Vacuum sleeve 13 can also be extended if necessary, and a heat-insulating elastic washer is placed in the interlayer of the joint.

Central shaft installation: The central shaft is an aluminum-zinc-plated seamless steel pipe (10 in Figure 1). First, several layers of (and partially stuck) aluminum-plastic are wound on both ends of a length of its vacuum sleeve. Composite film, the reflective layer is all outward. In the middle section between the two ends, a few layers are wound less, the purpose is to make it easier to put on the vacuum sleeve, and it is required to put it on, just not loose and not too tight. This is The multi-layer composite film is used for the purpose of a little elasticity and reflection of heat radiation. The central axis only plays the role of a skeleton for lifting and installation.

A vacuum disc (12 of Fig. 1) and Fig. 4 are placed on the central axis 10 at the two ends of the vacuum sleeve 13, respectively, and a heat-insulating elastic cap (7 of Fig. 1) is respectively adorned outside. Put an end cover 8 and a hoop 11 on each end (Fig. 1), and tighten the bolts so that they are fastened together with the central shaft (refer to Fig. 2 and Fig. 3).

The diameter of the outlet pipe of the comb-shaped cross-section spiral flow channel is round, (there is a short section at the beginning that transitions from a rectangle to a round pipe). The coupling nut 15 and the heat-insulating elastic ring 14 " are used as the positioning effect (Fig. 1) of the joint of two butt vacuum pipes. Because the shape and effect of the coupling nut 15 are the same as the split nuts of the mechanical industry lathe screw mandrel. Use the butt joint The measure of the vacuum tube is to take into account the technical difficulties in the manufacture of too long large vacuum tubes, so Figure 1 shows the structure of the butt-connected vacuum tube and the comb-shaped cross-section spiral flow channel that does not need to be connected.

The design of the expansion deflection arc 6, because the requirements of the diameter and length of the vacuum tube far exceed the national standard, and because the deflection of the glass is very small, the deflection is only shown when the span is quite large. Figure 9 is the production of the expansion deflection arc: a is blown into a waisted double-layer circular glass body with a mold; b uses an automatic notch machine or laser to cut off the remaining material at the dotted line on the edge; c uses the inner glass tube of the vacuum tube It is welded with R-R; d is welded with the outer glass tube of the vacuum tube at j-j. When the inner and outer glass tubes are welded with the deflection arc, it is better to use a concentric (coaxial) clamp instead of the commonly used metal elastic bracket. For example, in Figure C, use the three-point positioning of the inner hole circumference of the deflection arc, and then locate the three-point positioning of the inner hole circumference of the inner glass tube, so that the two three points of the fixture determine the center of a circle and keep it concentric. In Figure d, The same fixture is positioned at three points on the outer diameter circumference of the outer glass tube. The gap between the expansion deflection arc and the surrounding rigid parts is filled with glass wool.

Usually the getter piece and the getter are welded on the elastic bracket, but now they can only be welded on the copper wire or Dumet wire with a diameter of <φ0.8mm, and then put into the suction pipe to hang the evaporable barium-titanium getter in the vacuum In the layer, the metal wire and the suction pipe are melted and sealed together.

Vacuum disc 12, in the vacuum sleeve 13, preferably use vacuum-plated magnesium reflective layer, (this technology is economical and simple than electroless silver plating, although performance is slightly inferior).

The present invention must be installed and used in conjunction with the compound parabolic concentrator CPC, so that the entire cylindrical surface of the glass large vacuum tube heat collector is irradiated by sunlight, and the effect of the maximum heating surface is exerted.

These spiral flow channels can also be in the form of multi-head spirals, that is, there can be no gaps between each flow channel section, one next to each other, and the spectrally selective coating in Figure 10 at this time is omitted, and only the metal spiral flow channels The outer surface is coated with a spectrally selective coating.

Claims (3)

1. A comb-shaped cross-section spiral channel solar collector tube, comprising a glass tube made of fully transparent glass, a metal flow channel is housed in this glass tube, and it is characterized in that: the glass tube is made of different pipe diameters. Inner and outer glass tubes are formed, one end of the inner and outer glass tubes is welded to form an annular mouth, and an interlayer is formed between the inner and outer glass tubes; the other ends of the inner and outer glass tubes are made before welding. form a circular expansion deflection arc, and use the deflection of the glass to offset the expansion difference between the inner and outer glass tubes; the glass tube interlayer is evacuated; the metal flow channel is a spiral with a metal comb-shaped section The flow channel is coated with a spectrally selective coating film on the surface of the spiral flow channel of the metal comb-shaped section, and a working medium is set in the spiral flow channel of the metal comb-shaped section. The working medium is water, air, or antifreeze liquid. 2. The comb-shaped cross-section spiral channel solar heat collection tube according to claim 1, characterized in that: the ends of the two annular openings of the glass tubes are butted with each other. 3. According to claim 1, the comb-shaped cross-section spiral channel solar heat collector tube is characterized in that: the spiral of the spiral flow channel of the metal comb-shaped cross-section is a single-head spiral or a multi-head spiral, and the metal comb of a single-head spiral There is a gap between the spiral flow channels of the cross-section, so as to maintain a certain helix angle and flow rate of the working medium; there is no gap between the sections of the spiral flow channels of the metal comb-shaped cross-section of the multi-head spiral, which can maintain a large spiral lift. Angle, increase the flow rate of working fluid and heating area.

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