A kind of plate solar collector absorbing film
Technical field
The present invention relates to the plate solar collector technical field, more specifically, relate to a kind of plate solar collector absorbing film.
Background technology
Solar energy generally refers to the emittance of sunshine, in the modern times generally as generating.Form the biological just main light and heat existence that provides with the sun from the earth, and also understand with sun dry spare from the ancient human, and as the method for preserving food, as salt manufacturing and solarization cured fish etc.But under fossil fuel reduces, just intentionally solar energy is further developed.The utilization of solar energy has Passive use (photo-thermal conversion) and opto-electronic conversion dual mode.A kind of emerging regenerative resource of solar electrical energy generation.
Plate solar collector is a kind of device that absorbs solar radiation and the thermal energy transfer that produces is arrived heat transfer medium.Although solar thermal collector itself is not whole solar energy utilization system, the end product that neither directly satisfy the needs of consumers, it is the critical component that forms various Solar Energy Heat Utilization System.No matter be solar water heater, solar cooker, solar energy greenhouse, or solar refrigeration and air-conditioning, solar seawater desalination, solar energy thermal-power-generating etc., all be unable to do without solar thermal collector, be all with power or the core component of solar thermal collector as system.Solar thermal collector can be classified with several different methods, comprising the type by heat transfer medium classify, by the solar radiation that enters aperture whether change direction classify, by whether follow the tracks of the sun classify, by whether having the vacuum space to classify, classify by operating temperature etc.Comprehensive various heat collector type, vacuum tube collector and flat plate collector are used the most general, wherein compare vacuum tube collector, and it is high that flat plate collector has absorption efficiency, simple installation, long service life, floor space is little, is easy to and the characteristics such as Integration of building.The solar energy heating product of the state such as American-European, mainly in the majority with flat-plate collector at present, domesticly be dominant with the vacuum tube heat collecting type.In recent years along with the development in the fields such as technology of preparing, novel absorption film system, flat plate collector development is at home also more and more paid attention to.The hot property of heat collector is the major criterion in solar product, its major technique comes from the absorber coatings of heat collector, the optional membrane is an important subject in technical field of solar utilization technique always, according to statistics, 70% heat collector uses PVD or the splash coating of high selectivity, 11% adopts black chromium, the solar energy coating that 19% heat collector uses paint to be coated with.The preparation method of solar spectrum selective absorbing film system is sputter coating, and equipment operating is simple and easy, and prepared rete absorptivity is higher, and film is that quality is higher, is applicable to the large tracts of land batch production.Magnetically controlled sputter method is to use aspect preparation comparatively extensively at selective absorbing film, but still has further improved space.
The critical component of heat collector is exactly plate core of solar heat-collecting, mostly adopts now the compound board-like material of copper aluminium to make.The existing most absorptivity of plate solar collector absorbing film is lower, and emissivity is higher, and film structure is complicated, and rete is insecure, unstable.
Summary of the invention
The present invention is for overcoming the described at least a defective of above-mentioned prior art, and a kind of plate solar collector absorbing film that can realize absorbing the solar spectral of visible waveband and reflective infrared wave band is provided.
For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of plate solar collector absorbing film, wherein, film structure is
G ︱ α
1M
1β
1Cα
2M
2β
2C ︱ A, wherein, G represents substrate, A represents air, M
1Represent metallic reflector, M
2Represent metal absorption layer, C represents dielectric layer, α
1Represent metallic reflector M
1Thickness, α
2Metal absorption layer M
2Thickness, β
1, β
2Represent the thickness of dielectric layer C.Absorbing film single face on substrate G is coated with metallic reflector M
1, dielectric layer C, metal absorption layer M
2, dielectric layer C.The plate solar collector absorbing film structure of the novel absorption visible waveband that single face is coated with and reflective infrared wave band, this film structure makes absorbing film have the absorptivity of higher effective solar thermal collector absorption spectrum under the prerequisite of visual field absorption and near-infrared reflection, and has lower emissivity.This absorbing film has improved the endothermic effect of plate solar collector, and by wider infrared external reflection design, the plate solar collector emissivity is declined to a great extent, and can effectively improve the heat absorption degree of depth.
Further, the material of described substrate G is copper or stainless steel; Described metallic reflector M
1Material be Ag or Al; The material of described dielectric layer C is Al
2O
3Or SiO
2Described metal absorption layer M
2Material be W or Mo.
Wherein the absorbing membranous layer except substrate all adopts magnetically controlled sputter method preparation, described metallic reflector M after preparation
1Thickness alpha
1Be not less than 50nm; The thickness β of described dielectric layer C
1Be 65~90nm, β
2Be 75~100nm; Described metal absorption layer M
2Thickness alpha
2Be 5~20nm.
It is by metallic reflector M that film owner of the present invention wants structure
1, dielectric layer C, metal absorption layer M
2With the four-layer structure that dielectric layer C forms, it is a kind of absorbing film that can realize absorbing visible waveband and reflective infrared wave band.By choosing metal material and dielectric material formation inteferometer coating with selection absorbent properties be, and be that bottom is introduced the metallic red outer reflective layer at film, making film is that the effect that reaches is: realize high the absorption at the 380nm-1000nm wave band, the average absorption rate is greater than 95%, realize high reflection at the above wave band of 2500nm, average reflectance is greater than more than 95%.The present invention has the high reflective design of the high absorber portion of wider visible light and infrared band.
Compared with prior art, beneficial effect is: the broad absorption band design of plate solar collector absorbing film of the present invention can effectively improve the endothermic effect of absorbing film, make it have high-absorbility greater than 90%, in the high reflective design of infrared band, the relative existing products in markets of emissivity of film system is further reduced simultaneously.The single-sided structure of absorbing film has advantages of that spectral characteristic is stable, film structure is simple, rete is firm, weatherability is strong, satisfies the long-term instructions for use of plate solar collector, and has good preparation repeatability.Film structure is fit to general Optimization Software, can reach better effect.
Description of drawings
Fig. 1 is absorbing film structural representation of the present invention.
Fig. 2 is each layer function schematic diagram (reflectivity) schematic diagram of absorbing film of the present invention.
Fig. 3 is that before optimizing, integral membrane is design absorbance curves schematic diagram.
Fig. 4 is that after optimizing, integral membrane is design absorbance curves schematic diagram.
Fig. 5 is that after optimizing, integral membrane is design reflectivity rate schematic diagram.
Fig. 6 absorbing film actual measurement absorption spectrum schematic diagram.
The specific embodiment
Accompanying drawing only is used for exemplary illustration, can not be interpreted as the restriction to this patent; For better explanation the present embodiment, some parts of accompanying drawing have omission, zoom in or out, and do not represent the size of actual product; To those skilled in the art, in accompanying drawing some known features and explanation thereof may to omit be understandable.
As shown in Figure 1, a kind of plate solar collector absorbing film, wherein, film structure is
G ︱ α
1M
1β
1Cα
2M
2β
2C ︱ A, wherein, G represents substrate, A represents air, M
1Represent metallic reflector, M
2Represent metal absorption layer, C represents dielectric layer, α
1Represent metallic reflector M
1Thickness, α
2Metal absorption layer M
2Thickness, β
1, β
2Represent the thickness of dielectric layer C.Absorbing film single face on substrate G is coated with metallic reflector M
1, dielectric layer C, metal absorption layer M
2, dielectric layer C.The novel absorption visible waveband that single face is coated with and the plate solar collector absorbing film of reflective infrared wave band, this film structure makes absorbing film have the absorptivity of higher effective solar thermal collector absorption spectrum under the prerequisite of visual field absorption and near-infrared reflection, and has lower emissivity.
Further, the material of substrate G is copper or stainless steel; Metallic reflector M
1Material be Ag or Al; The material of dielectric layer C is Al
2O
3Or SiO
2Metal absorption layer M
2Material be W or Mo.It is metallic reflector M that the film owner wants structure
1, dielectric layer C, metal absorption layer M
2Four-layer structure with dielectric layer C composition.
As shown in Figure 1, the flat-plate solar collector absorbing film of this structure, it mainly comprise heat collector substrate 1, be formed on metallic red outer reflective layer 2 in copper substrate 1, be formed on medium interfering layer 3 on metallic red outer reflective layer 2, be formed on metal absorption layer 4 on medium interfering layer 3, be formed on anti-reflection layer 5 on metal absorption layer 4.Film be each layer function as shown in Figure 2, underlying metal infrared reflecting layer 2 is realized full wave high reflection, reduces heat collector inside to external radiation, reduces heat loss; Medium interfering layer 3 has the anti-reflection effect, and forming inteferometer coating with metal absorption layer 4 and anti-reflection layer 5 simultaneously is to widen the absorption bands scope; Metal absorption layer 4 is realized the selective absorption function of film system; Anti-reflection layer 5 reduces the reflection loss of sunshine on film system surface and plays simultaneously the protective effect of film system.
Wherein, the absorbing membranous layer except substrate all adopts magnetically controlled sputter method preparation, described metallic reflector M after preparation
1Thickness alpha
1Be not less than 50nm; The thickness β of described dielectric layer C
1Be 65~90nm, β
2Be 75~100nm; Described metal absorption layer M
2Thickness alpha
2Be 5~20nm.
This structure is the absorbing film that is comprised of metal and dielectric material that is coated with at the substrate single face:
G︱α
1M
1β
1Cα
2?M
2β
2C︱A
Fig. 3 is with the integral membrane of 1/4th centre wavelength optical thicknesses system design absorbance curves, in order to access the absorption spectrum of better absorption visible waveband and reflective infrared wave band, from point of view of practicability, all retes are only carried out thickness optimization, and the optimization precision is 2 significant digits.Optimization Software uses " Essential Macleod " commercial optical coating software, and the concrete film structure after optimization is: 65.19 M
177.78C11.86 M
292.50C M wherein
1, M
2Represent metal, C represents dielectric material, and each concrete numerical value is each layer thickness value under the 550nm supervisory wavelength.Optimum results absorption line as shown in Figure 4, Fig. 5 are the reflection spectral lines after optimizing, and use the high accuracy coating machine can realize this design result fully.
The present invention uses domestic full-automatic magnetic control radio frequency coating machine to carry out experiment and is coated with.Select copper product as substrate, being coated with selective absorbing film is due to the requirement of tester test condition, to put into simultaneously different base materials (Si, SiO
2The surface twin polishing) as the characteristic test sample substrate.Base vacuum air pressure is controlled at 5 * 10
-4Handkerchief.Jet-plating metallization membrane material method adopts radio-frequency sputtering, passes into argon gas (flow 70sccm), and air pressure maintains 0.3 handkerchief, and the sputtering power of metallic reflector and metal absorption layer is respectively 280W and 100W; Generate the deielectric-coating material and adopt the reaction sputter, sputtering power 280W passes into argon gas (flow 60sccm) and oxygen (flow 10sccm), and operating air pressure maintains 0.3 handkerchief.Whole film is to be coated with by automatic control mode to realize, gets sheet until be coated with to complete.
Based on above-mentioned theory design and experiment preparation, with the spectrophotometer of Shimadzu company, model UV-3101PC, the absorption spectra of measurement wave-length coverage 380nm to 3200nm, as shown in Figure 6.Experimental result shows, repeatedly be coated with measure in shown good stability and repeated.
No longer narrate at this, describe position relationship in accompanying drawing and only be used for exemplary illustration, can not be interpreted as the restriction to this patent.
Obviously, the above embodiment of the present invention is only for example of the present invention clearly is described, and is not to be restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here need not also can't give all embodiments exhaustive.All any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in the protection domain of claim of the present invention.