CN202813845U - U-shaped multitubular evacuated collector tube - Google Patents

Abstract

The utility model relates to the technical field of solar energy and discloses a U-shaped multitubular evacuated collector tube. The U-shaped multitubular evacuated collector tube comprises a transparent shell and a plurality of U-shaped slim tubes, wherein the U-shaped slim tubes are arranged in parallel with each other in the shell; the U-shaped slim tubes are connected in parallel; a vacuum is arranged formed between the shell and the U-shaped slim tubes; and selective absorbing coatings are respectively coated on the surfaces of the U-shaped slim tubes. Multiple collector tube bundles are intensively used, so that the U-shaped multitubular evacuated collector tube disclosed by the utility model has the advantages that the temperature rise is rapid, the temperature difference is small, the heat exchange efficiency is high, and the application range is broad.

Description

U-shaped multitube vacuum heat collection pipe

Technical field

The utility model relates to technical field of solar, particularly a kind of U-shaped multitube vacuum heat collection pipe.

Background technology

In the heat utilization of solar energy, key is that the radiant energy with the sun is converted to heat energy.Because solar energy relatively disperses, and must manage it is put together, so solar thermal collector is the various key components of utilizing solar energy equipment.Solar thermal collector is to absorb solar radiation to make it the device that is converted to heat energy and passes to thermal medium.Although solar thermal collector is not the end product that directly satisfies 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, all is as the power of system or core component with solar thermal collector.Common are plate, vacuum tube type and focus solar collector.

The 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.Commonly used is the all-glass vacuum tube type thermal-collecting tube, consisted of by inside and outside two glass tubes, form vacuum chamber between the inner and outer pipe, the outer surface of inner tube is provided with solar selectively absorbing coating, transmission heat transfer medium (water) in the 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, and heat transfer rate is slow, and available hot water amount is few, all the time according to the time heat loss increase, can not export the hot water of higher temperature.Present vacuum tube type heat collection pipe generally is applied in the low temperature domestic solar water heater occasion about 20-80 ℃, can't 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 efficient, low thermal emissivity, elevated operating temperature.

The utility model content

The purpose of this utility model is to provide a kind of U-shaped multitube vacuum heat collection pipe, solves the existing lower limitation of vacuum heat collection pipe operating temperature, promotes the high temperature of thermal-collecting tube to use.

For solving the problems of the technologies described above, the utility model provides U-shaped multitube vacuum heat collection pipe, comprising: transparent shell; Many U-shaped tubules are arranged in enclosure interior parallel to each other, are connected in parallel between the many U-shaped tubules; Be set to vacuum between housing and many U-shaped tubules, many U-shaped tubule surfaces apply coating for selective absorption.

Optionally, the diameter of many U-shaped tubules is 3-10mm.

Optionally, the pipe thickness of many U-shaped tubules is 0.3mm-1mm.

Optionally, many U-shaped tubules are metal tube or glass tube.

Optionally, between coating for selective absorption and the U-shaped tubule of Duo Gen, lay metallic reflector.

Optionally, metallic reflector is silver foil or aluminium foil.

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

Optionally, the transparent shell lateral wall applies anti-reflection film.

Optionally, manage with mother after many U-shaped tubule parallel connections and be connected.

The utility model compared with prior art, the main distinction and effect thereof are: the sectional area that many U-shaped tubules are compared with single bassoon is less, and is few with oil mass, so the preheat temperature loss is less, the short distance temperature rise is faster, has good, the advantage such as have a narrow range of temperature of heat exchange, greatly reduces pre-heat loss.The optimal design of many U-shaped tubule radiuses, conversion and the exchange efficiency of solar energy optical-thermal have greatly been improved, the coating for selective absorption that is plated in the vacuum heat-collecting tube outer surface is used for absorbing the sunshine visible light, reduce infra-red radiation, raising is to the absorption efficiency of sunshine, reduce radiation efficiency, thereby improve the operating temperature of thermal-collecting tube; The highly reflective coatint that is plated in the vacuum heat collection pipe below is used for reducing radiation loss as far as possible, thereby further improves the operating temperature of thermal-collecting tube.

Description of drawings

Fig. 1 is the structural representation of the first embodiment of the U-shaped multitube vacuum heat collection pipe of the utility model;

Fig. 2 is the cutaway view of the first embodiment of the U-shaped multitube vacuum heat collection pipe of the utility model;

Fig. 3 is the diameter optimal datagram of the U-shaped multitube vacuum heat collection pipe of the utility model;

Fig. 4 is the structural representation of the second embodiment of the U-shaped multitube vacuum heat collection pipe of the utility model.

The specific embodiment

In the following description, in order to make the 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 with based on many variations and the modification of following each embodiment, also can realize each claim of the application technical scheme required for protection.

For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with accompanying drawing embodiment of the present utility model is described in further detail.Same or analogous member uses the same reference numerals to represent among the figure.

Referring to Fig. 1, Fig. 2, show the first embodiment of U-shaped multitube vacuum heat collection pipe of the present utility model, as shown in the figure, this thermal-collecting tube comprises: the transparent shell 1 of elliptical cylinder-shape; Be arranged in parallel to each other many U-shaped tubules 2 of housing 1 inside, rear and female pipe 3 in parallel is connected between the many U-shaped tubules 2; Seal between housing 1 and many U-shaped tubules 2, be set to vacuum, many U-shaped tubule 2 surfaces apply coating for selective absorption.Many U-shaped tubules 2 can be metal tube or glass tube.Metal tube can be applied in the occasion of higher pressure, and lower, the technology maturation of the cost of glass tube is with a wide range of applications.

The sectional area that many U-shaped tubules are compared with single bassoon is less, and is few with oil mass, so the preheat temperature loss is less, the short distance temperature rise is faster, has good, the advantage such as have a narrow range of temperature of heat exchange, greatly reduces pre-heat loss.Many vacuum heat collection pipes that are connected in parallel have improved heat exchange area and heat exchange efficiency, can be with fluid heating to a higher temperature of flowing through in situation about inputting with homenergic.Ellipsoidal structure can be saved the volume of thermal-collecting tube, greatly reduces taking up room of thermal-collecting tube, improves the space hold rate.

The diameter of many U-shaped tubules is 3-10mm, and the pipe thickness of many U-shaped tubules is 0.3mm-1mm.Referring to Fig. 3, in the pipeline fluid heat transfer process, the relation between heat flow density q and the heat transfer temperature difference Δ T is as follows: q=h Δ T, h are convection transfer rate, and 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 the exchange capability of heat of considering fluid and tube wall, still need and consider pipeline heat radiation itself, the media flow required drive consumes, pipeline itself heat storage etc., guaranteeing to consider the total amount adduction of above-mentioned each amount in the identical coefficient of heat transfer situation.

The heat dissipation capacity of pipeline own is:

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

$=n\frac{T-T_a}{\frac{\ln (({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA00002084644100031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n+2{\mathrm{\&delta;}}_{\mathrm{insulate}})/({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA00002084644100031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n))}{2\mathrm{\&pi;\&lambda;}}+\frac{1}{\mathrm{h\&pi;}({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA00002084644100031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n+{2\mathrm{\&delta;}}_{\mathrm{insulate}})}}$

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:

$P_{h-\mathrm{heating},\mathrm{steel}}={\mathrm{nc}}_{p,\mathrm{steel}}{\mathrm{\&rho;}}_{\mathrm{steel}}\frac{\mathrm{\&pi;}}{4}{(({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA00002084644100031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n)+{2\mathrm{\&delta;}}_{\mathrm{wallthick}})}^2-{({\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA00002084644100031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0/n)}^2)\mathrm{\&Delta;T}/t/3600$

$P_{h-\mathrm{heating},\mathrm{oil}}=c_{p,\mathrm{oil}}{\mathrm{\&rho;}}_{\mathrm{oil}}\frac{\mathrm{\&pi;}}{4}\left(\frac{{\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA00002084644100031.png"\; state="\{\{state\}\}">d</figure-callout>}}_0^2}{n}\right)\mathrm{\&Delta;T}/t/3600$

N is pipeline quantity, and take 70mm as diameter, pipeline quantity is long-pending identical with product and 70mm pipe section that pipe section amasss.When coefficient of heat transfer h remains unchanged, above-mentioned every merging is investigated, its result as shown in Figure 3, so the minimum power consumption place is the pipeline optimum size, the therefore more excellent diameter 3-10mm that is of a size of of many U-shaped tubules, wall thickness 0.3mm-1mm.The optimal design of many U-shaped tubule radiuses has improved conversion and the exchange efficiency of solar energy optical-thermal greatly.

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 little not plane surface to consist of.The materials such as Si/Ge/-Al/Au/Cu/Al/Pt/W/Ni can be selected in semiconductor absorption-metallic reflection tandem surface.The 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.Little not plane surface is optional with materials such as Cu, Ni, SS, Re or W.In the present embodiment, coating for selective absorption is made of metallic reflector and the semiconductor absorption layer that is formed on the metallic reflector.The metallic reflection layer material is Ge, and the material of semiconductor absorption layer is Al.The coating for selective absorption that is plated in the vacuum heat-collecting tube outer surface is used for absorbing the sunshine visible light, reduces infra-red radiation, improves the absorption efficiency to sunshine, reduces radiation efficiency, thereby improves the operating temperature of thermal-collecting tube.

Between coating for selective absorption and the U-shaped tubule 2 of Duo Gen, lay metallic reflector.Metallic reflector is silver foil or aluminium foil.Be used for reducing radiation loss as far as possible, improve the operating temperature of U-shaped multitube vacuum heat collection pipe.

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 utility model, the difference of this embodiment and the first embodiment is: transparent shell 1 is shaped as cylindrical, and cylindrical structural is because vacuum heat-insulating layer is thicker, have better heat insulation effect, can be applied in the occasion that insulation is had relatively high expectations.

Although by reference some preferred embodiment of the present utility model, the utility model is illustrated and describes, 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 do not depart from spirit and scope of the present utility model.

Claims (9)

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

Transparent shell;

Many U-shaped tubules are arranged in described enclosure interior parallel to each other, are connected in parallel between the many U-shaped tubules;

Be set to vacuum between described housing and many U-shaped tubules, many U-shaped tubule surfaces apply coating for selective absorption.

2. thermal-collecting tube according to claim 1 is characterized in that, the diameter of described many U-shaped tubules is 3-10mm.

3. thermal-collecting tube according to claim 2 is characterized in that, the pipe thickness of described many U-shaped tubules is 0.3mm-1mm.

4. thermal-collecting tube according to claim 3 is characterized in that, described many U-shaped tubules are metal tube or glass tube.

5. thermal-collecting tube according to claim 4 is characterized in that, lays metallic reflector between described coating for selective absorption and described many U-shaped tubules.

6. thermal-collecting tube according to claim 5 is characterized in that, described metallic reflector is silver foil or aluminium foil.

7. thermal-collecting tube according to claim 6 is characterized in that, described transparent shell is cylindrical or elliptical cylinder-shape.

8. thermal-collecting tube according to claim 7 is characterized in that, described transparent shell lateral wall applies anti-reflection film.

9. thermal-collecting tube according to claim 8 is characterized in that, manages with mother after the described many U-shaped tubule parallel connections to be connected.

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