CN103673343A - Snakelike multi-tube evacuated collector tube - Google Patents

Abstract

The invention relates to the technical field of solar energy, and discloses a snakelike multi-tube evacuated collector tube which comprises a transparent shell and a snakelike thin tube formed by connecting a plurality of parallel thin tubes in series. The space between the shell and the snakelike thin tube is vacuum. According to the snakelike multi-tube evacuated collector tube, multiple heat collector tube bundles are connected in series, and the snakelike multi-tube evacuated collector tube has the advantages of being fast in temperature rise, small in temperature difference, high in heat exchange efficiency, wide in application range and the like.

Description

Snakelike multitube vacuum heat collection pipe

Technical field

The present invention relates to technical field of solar, particularly a kind of snakelike multitube vacuum heat collection pipe.

Background technology

In the heat utilization of solar energy, key is that the radiant energy of the sun is converted to heat energy.Because solar energy relatively disperses, must manage it to put together, so solar thermal collector is the various key components of utilizing solar energy equipment.Solar thermal collector is to make it for absorbing solar radiation the device that is converted to heat energy and passes to thermal medium.Although solar thermal collector is not the end product directly satisfying the needs of consumers, solar thermal collector is the critical component that forms various Solar Energy Heat Utilization System.Being that solar water heater, solar cooker, active solar house, solar energy greenhouse or solar energy drying, solar industry heating, solar energy thermal-power-generating etc. all be unable to do without solar thermal collector, is all to using solar thermal collector as the power of system or core component.Common are plate, vacuum tube type and focus solar collector.

Vacuum tube type solar energy heat collector can be subdivided into all-glass vacuum tube type, heat-tube vacuum tubular type, U-shaped pipe vacuum tube formula.Conventional is all-glass vacuum tube type thermal-collecting tube, by inside and outside two glass tubes, formed, between inner and outer pipe, form vacuum chamber, the outer surface of inner tube is provided with solar selectively absorbing coating, transmission heat transfer medium (water) in inner tube, the thermal-collecting tube of this structure has safety, energy-saving and environmental protection, economic dispatch advantage.But its shortcoming is to bear that hydraulic pressure is low, water-holding quantity is many, heat transfer rate is slow, and available hot water amount is few, all the time according to time heat loss increase, can not export the hot water of higher temperature.Current vacuum tube type heat collection pipe is generally applied in the low temperature domestic solar water heater occasion of 20-80 ℃ of left and right, cannot be used in the occasion that needs elevated operating temperature in 150-400 ℃.

Therefore, this area is in the urgent need to researching and developing the solar energy heat collection pipe of a kind of high heat absorption efficiency, low thermal emissivity, elevated operating temperature.

Summary of the invention

The object of the present invention is to provide a kind of snakelike multitube vacuum heat collection pipe, solve the lower limitation of existing thermal-collecting tube operating temperature, promote the high temperature application of thermal-collecting tube.

For solving the problems of the technologies described above, the invention provides snakelike multitube vacuum heat collection pipe, comprising: transparent shell; Snakelike tubule, is composed in series by many tubules parallel to each other; Between housing and snakelike tubule, be set to vacuum.

Preferably, the diameter of snakelike tubule is 3-10mm.

Preferably, the pipe thickness of snakelike tubule is 0.3mm-1mm.

Preferably, snakelike tubule is metal tube or glass tube.

Preferably, the generating surface at snakelike tubule arranges corrugated heat absorbing fins, heat absorbing fins surface coating coating for selective absorption.

Preferably, between heat absorbing fins and coating for selective absorption, lay metallic reflector.

Preferably, metallic reflector is silver foil or aluminium foil.

Preferably, snakelike tubule is two-layer.

Preferably, transparent shell is cylindrical or elliptical cylinder-shape.

Preferably, transparent shell lateral wall applies anti-reflection film.

The present invention compared with prior art, the main distinction and effect thereof are: the sectional area that the snake pipe that many tubules are in series is compared with single bassoon is less, few by oil mass, therefore preheat temperature loss is less, short distance temperature rise is faster, have that heat exchange is good, the advantage such as have a narrow range of temperature, greatly reduce pre-heat loss.The optimal design of snakelike tubule radius, conversion and the exchange efficiency of solar energy optical-thermal have greatly been improved, the waveform heat absorbing fins that is arranged on coiled pipe top forms light trapping, make light at heat absorbing fins surface multiple reflections, improve absorptivity, be plated in the coating for selective absorption of waveform heat absorbing fins outer surface for absorbing sunshine visible ray, reduce infra-red radiation, further improve the absorption efficiency to sunshine, reduce radiation efficiency, thereby improve the operating temperature of thermal-collecting tube; Metal reflective coating is used for reducing radiation loss as far as possible, thereby further improves the operating temperature of thermal-collecting tube.

Accompanying drawing explanation

Fig. 1 is the structural representation of the first embodiment of the snakelike multitube vacuum heat collection pipe of the present invention;

Fig. 2 is the cut-away view of the first embodiment of the snakelike multitube vacuum heat collection pipe of the present invention;

Fig. 3 is the diameter optimal datagram of the snakelike multitube vacuum heat collection pipe of the present invention;

Fig. 4 is the structural representation of the second embodiment of the snakelike multitube vacuum heat collection pipe of the present invention.

The specific embodiment

In the following description, in order to make reader understand the application better, many ins and outs have been proposed.But, persons of ordinary skill in the art may appreciate that even without these ins and outs and the many variations based on following embodiment and modification, also can realize each claim of the application technical scheme required for protection.

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, embodiments of the present invention are described in further detail.In figure, same or analogous member uses the same reference numerals to represent.

Referring to Fig. 1, Fig. 2, show the first embodiment of snakelike multitube vacuum heat collection pipe of the present invention, as shown in the figure, this thermal-collecting tube comprises: columniform transparent shell 1; Between snakelike tubule 2,1 housings that are composed in series by many tubules parallel to each other and snakelike tubule 2, be set to vacuum.Snakelike tubule 2 can be metal tube or glass tube.Metal tube can be applied in the occasion of higher pressure, and the cost of glass tube is lower, technology maturation, is with a wide range of applications.

The sectional area that the snake pipe that many tubules are in series is compared with single bassoon is less, few by oil mass, therefore preheat temperature loss is less, short distance temperature rise is faster, has that heat exchange is good, the advantage such as have a narrow range of temperature, and greatly reduces pre-heat loss.

The diameter of many tubules is 3-10mm, and the pipe thickness of many tubules is 0.3mm-1mm.Referring to Fig. 3, in pipeline fluid heat transfer process, the relation between heat flow density q and heat transfer temperature difference △ T is as follows: q=h △ T, and h is convection transfer rate, it is as follows with the interior velocity of medium u of pipe and pipeline inner diameter d relation:

therefore,

consider the heat transfer effect of a heat exchange pipeline, except considering the exchange capability of heat of fluid and tube wall, still need and consider pipeline heat radiation itself, media flow required drive consumes, pipeline itself heat storage etc., guaranteeing, in identical coefficient of heat transfer situation, to consider the total amount adduction of above-mentioned each amount.

The heat dissipation capacity of pipeline own is:

$P_{h\_\mathrm{pipe}}=n\frac{T-T_a}{\frac{\ln ((d+2{\mathrm{\δ}}_{\mathrm{insulate}})/d)}{2\mathrm{\π\λ}}+\frac{1}{\mathrm{h\π}(d+2{\mathrm{\δ}}_{\mathrm{insulate}})}}$

$=n\frac{T-T_a}{\frac{\ln (({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="DEST\_PATH\_HDA00002589515200031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n+2{\mathrm{\&delta;}}_{\mathrm{insulate}})/({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="DEST\_PATH\_HDA00002589515200031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n))}{2\mathrm{\&pi;\&lambda;}}+\frac{1}{\mathrm{h\&pi;}({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="DEST\_PATH\_HDA00002589515200031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n+2{\mathrm{\&delta;}}_{\mathrm{insulate}})}}$

The consumption of power is:

$P_{h-\mathrm{pump}}=\frac{5\mathrm{\&rho;\&xi;\&pi;}{d}_0{u}^3}{16}$

The thermal capacitance of pipeline own:

$P_{h-\mathrm{heating},\mathrm{steel}}={\mathrm{nc}}_{p,\mathrm{steel}}{\mathrm{\&rho;}}_{\mathrm{steel}}\frac{\mathrm{\&pi;}}{4}{(({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="DEST\_PATH\_HDA00002589515200031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n)+2{\mathrm{\&delta;}}_{\mathrm{wallthick}})}^2-{({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="DEST\_PATH\_HDA00002589515200031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n)}^2)\mathrm{\&Delta;T}/t/3600$

$P_{h-\mathrm{heating},\mathrm{oil}}=c_{p,\mathrm{oil}}{\mathrm{\&rho;}}_{\mathrm{oil}}\frac{\mathrm{\&pi;}}{4}\left(\frac{{\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="DEST\_PATH\_HDA00002589515200031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0^2}{n}\right)\mathrm{\&Delta;T}/t/3600$

N is pipeline quantity, take 70mm as diameter, and the product that pipeline quantity is long-pending with pipe section and 70mm pipe section are long-pending identical.When coefficient of heat transfer h remains unchanged, above-mentioned every merging to be investigated, as shown in Figure 3, so minimum power consumption place is pipeline optimum size to its result, the therefore more excellent diameter 3-10mm that is of a size of of many tubules, wall thickness 0.3mm-1mm.The optimal design of many tubule radiuses, has improved conversion and the exchange efficiency of solar energy optical-thermal greatly.In certain specific embodiment, the single tube of snakelike tubule is of a size of Φ 6*0.6mm, and tube pitch is 10mm, and interlamellar spacing is 6mm.

Generating surface at snakelike tubule arranges corrugated heat absorbing fins 3, is arranged on the waveform heat absorbing fins 3 of coiled pipe top for chamber structure, can form light trapping, makes light at the surperficial multiple reflections of heat absorbing fins 3, improves absorptivity and heat transfer rate.

Heat absorbing fins surface applies coating for selective absorption.Coating for selective absorption can select the material structures such as semiconductor absorption-metallic reflection tandem surface, metal-dielectric composite, dielectric-metal interference stack surface, intrinsic selective absorption surface or micro-not plane surface to form.The materials such as Si/Ge/-Al/Au/Cu/Al/Pt/W/Ni can be selected in semiconductor absorption-metallic reflection tandem surface.Metal-dielectric composite can be selected Pt-Al ₂o ₃, Ni-SiO ₂, Ni/Co/Mo/Au/W/Pt-Al ₂o ₃, Al-AlN; Mo-MoO ₂or the material such as W-WO2.ZrB can be selected in dielectric-metal interference stack surface ₂, Mo/Co/Cr-Cr ₂o ₃, Mo-AlN or Au-TiO ₂the materials such as/MgO.Intrinsic Gettering selective absorption surface W, HfC or Cu ₂the materials such as S.Micro-not plane surface is optional with materials such as Cu, Ni, SS, Re or W.In the present embodiment, coating for selective absorption consists of metallic reflector and the semiconductor absorption layer being formed on metallic reflector.Metallic reflection layer material is Ge, and the material of semiconductor absorption layer is Al.Be plated in the coating for selective absorption of vacuum heat-collecting tube outer surface for absorbing sunshine visible ray, reduce infra-red radiation, improve the absorption efficiency to sunshine, reduce radiation efficiency, thereby improve the operating temperature of thermal-collecting tube.

Between coating for selective absorption and heat absorbing fins 3, lay metallic reflector.Metallic reflector is silver foil or aluminium foil.For reduce radiation loss as far as possible, improve the operating temperature of thermal-collecting tube.

Snakelike tubule 2 is two-layer.Double-deck heat absorption serpentine coil can more large-area contact heat absorbing fins, improves heat absorption efficiency.Porch at snakelike tubule is connected header 4 with exit, as the joint of snakelike multitube thermal-collecting tube.

Transparent shell 1 lateral wall applies anti-reflection film.Anti-reflection film is used for improving the impingement rate of sunshine, thereby further improves the operating temperature of thermal-collecting tube.

Referring to Fig. 4, show the second embodiment of the present invention, the difference of this embodiment and the first embodiment is: transparent shell 1 is shaped as ellipse, and ellipsoidal structure can be saved the volume of thermal-collecting tube, greatly reduce taking up room of thermal-collecting tube, improve the area utilization of thermal-collecting tube.

Although pass through with reference to some of the preferred embodiment of the invention, the present invention is illustrated and described, but those of ordinary skill in the art should be understood that and can do various changes to it in the form and details, and without departing from the spirit and scope of the present invention.

Claims (10)

1. a thermal-collecting tube, is characterized in that, comprising:

Transparent shell;

Snakelike tubule, is composed in series by many tubules parallel to each other;

Between described housing and snakelike tubule, be set to vacuum.

2. thermal-collecting tube according to claim 1, is characterized in that, the diameter of described snakelike tubule is 3-10mm.

3. thermal-collecting tube according to claim 2, is characterized in that, the pipe thickness of described snakelike tubule is 0.3mm-1mm.

4. thermal-collecting tube according to claim 3, is characterized in that, described snakelike tubule is metal tube or glass tube.

5. thermal-collecting tube according to claim 4, is characterized in that, at the generating surface of described snakelike tubule, corrugated heat absorbing fins is set, and heat absorbing fins surface applies coating for selective absorption.

6. thermal-collecting tube according to claim 5, is characterized in that, between heat absorbing fins and coating for selective absorption, lays metallic reflector.

7. thermal-collecting tube according to claim 6, is characterized in that, described metallic reflector is silver foil or aluminium foil.

8. thermal-collecting tube according to claim 7, is characterized in that, described snakelike tubule is two-layer.

9. thermal-collecting tube according to claim 8, is characterized in that, described transparent shell is cylindrical or elliptical cylinder-shape.

10. thermal-collecting tube according to claim 9, is characterized in that, described transparent shell lateral wall applies anti-reflection film.

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