US20020073988A1 - Solar collector element - Google Patents
Solar collector element Download PDFInfo
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- US20020073988A1 US20020073988A1 US10/029,493 US2949301A US2002073988A1 US 20020073988 A1 US20020073988 A1 US 20020073988A1 US 2949301 A US2949301 A US 2949301A US 2002073988 A1 US2002073988 A1 US 2002073988A1
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- Prior art keywords
- solar collector
- element according
- collector element
- layer
- absorber part
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/20—Bonding
- B23K26/21—Bonding by welding
- B23K26/22—Spot welding
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S10/00—Solar heat collectors using working fluids
- F24S10/70—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits
- F24S10/75—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits with enlarged surfaces, e.g. with protrusions or corrugations
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/20—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
- F24S70/225—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption for spectrally selective absorption
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/20—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
- F24S70/25—Coatings made of metallic material
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/30—Auxiliary coatings, e.g. anti-reflective coatings
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
- Y02E10/44—Heat exchange systems
Definitions
- the present invention relates to a solar collector element having an absorber part and having a tube for a heat-transfer liquid.
- the absorber part is a composite material having a metallic substrate with an optically active coating on a second side of the absorber part opposite the tube.
- absorber parts are required to have a maximum absorptivity in the solar wavelength region (approximately 300 to approximately 2500 nm) and a maximum reflectivity in the thermal radiation region (above approximately 2500 nm).
- Absorbers for flat collectors in which solar collector elements of the type described above with coated absorber parts that satisfy this demand for selective absorption to a high level, are known under the name Tinox.
- the material of the absorber parts comprises a copper strip substrate to which a layer of titanium oxynitride has been applied, followed by a covering layer of silicon dioxide.
- the tube which is connected to an absorber part likewise consists of copper and is soldered to the absorber part.
- the present invention is based on the object of providing a solar collector element of the type described in the introduction which, on the one hand, leads to a high light absorption and a high reflectivity in the solar radiation region and, on the other hand, which has improved use characteristics in particular under high thermal load operating conditions, and has a longer service life, in combination with a production method that involves minimum possible capital outlay. Furthermore, the invention is also intended to allow an optimum solution to the problem with regard to ensuring a strong mechanical joint and good heat transfer between the absorber part and the tube. Finally, the solar collector element is to be distinguished by the possibility of steady temperatures within the range of use of high-temperature collectors and also by high long-term chemical stability.
- the coating comprises a multilayer system which is composed of three layers, of which the top layer is a dielectric layer, preferably an oxide, fluoride or nitride layer of chemical composition MeO z , MeF r , MeN s , having a refractive index n ⁇ 1.8, and of which the middle layer is a chromium oxide layer of chemical composition CrO x , and of which the bottom layer consists of gold, silver, copper, chromium, aluminium and/or molybdenum.
- the indices x, z, r and s indicating a stoichiometric or non-stoichiometric ratio in the oxides, fluorides or nitrides.
- the optical multilayer system which is present according to the invention can firstly be applied advantageously, since there is no need for environmentally hazardous, in some cases toxic, salt solutions during production.
- the metallic layer of the optical multilayer system may be a sputtered layer or a layer which is produced by vaporization, in particular by electron bombardment or from thermal sources.
- the two upper layers of the optical multilayer system may likewise be sputtered layers, in particular layers produced by reactive sputtering, CVD or PECVD layers or layers produced by vaporization, in particular by electron bombardment or from thermal sources, so that the entire optical multilayer system comprises layers which are applied in vacuum order, in particular in a continuous process.
- the top layer may alternatively be a silicon oxide layer of chemical composition SiOy, where the index y once again indicates a stoichiometric or non-stoichiometric ratio in the oxide composition.
- the solar collector element according to the invention is also distinguished, on account of the ease of processing, in particular deforming, the composite material from which the absorber part is produced. This is primarily achieved on account of the metallic substrate, which may be made from copper or preferably from aluminium, by a production method which involves little complexity and by a high thermal conductivity. The latter property is particularly important since it allows rapid, highly efficient transfer of the heat taken up as a result of the light absorption to the heat-transfer liquid.
- the above processes for applying the layers of the system also advantageously enable the chemical composition MeO z , MeF r , MeN s of the top layer and the chemical composition CrO x of the chromium oxide layer, with regard to the indices x, y, z, r and s, to be not only set at defined, discrete values but also allows a stoichiometric or non-stoichiometric ratio between the oxidized substance and the oxygen to be varied continuously within defined limits.
- the refractive index of the reflection-reducing top layer (which is also responsible for increasing the mechanical load-bearing capacity (DIN 58196, part 5)) and the absorptivity of the chromium oxide layer (the absorptance decreasing as the value of the index x rises).
- a total light reflectivity determined in accordance with DIN 5036, part 3, on the side of the optical multilayer system to a preferred level of less than 5%.
- a high resistance to ageing it is also possible to ensure a high thermal stability, in such a manner that under a thermal load of 430° C./100 hours, only changes of less than 7%, and preferably of less than 4%, in the reflectivity occur.
- the substrate layer for example its excellent deformability, by means of which it withstands stresses produced in the production process of the solar collector element according to the invention during the shaping processes which are to be performed without problems, for example its high thermal conductivity and—in particular in the case of aluminium as substrate material—the capacity for a surface patterning which in the light wavelength region additionally promotes adsorption and is then followed by the other layers in relief, and moreover with a reflectance in the solar radiation region which reinforces the action of the metallic layer of the optical three-layer system;
- the metallic layer which, on account of its constituents, which have a high reflectivity and therefore a low emission in the thermal radiation region, takes account of the fact that, according to the Lambert-Bouguer law, the radiation characteristic is absorbed exponentially as the penetration depth grows, and for most inorganic substances is available as a store or thermal energy which can be passed on at even a very low depth (less than approximately 1 ⁇ m);
- top, in particular silicon oxide, layer the advantages of which have to some extent already been pointed out above and which, in addition to its antireflective action, also has a high transmittance and, as a result, increases the proportion of the radiation values in the solar region which can be absorbed by the chromium oxide layer;
- the solar collector element according to the invention is eminently suitable for the production of the solar collector element according to the invention. Therefore, by using the solar collector element according to the invention, not only is it possible to produce low-temperature collectors with an operating temperature of up to 100° C., but also it is possible to produce high-temperature collectors, in which steady temperatures of over 250° C. are possible.
- Beneath the optical multilayer system it is also possible to provide an intermediate layer on the substrate, the intermediate layer being responsible firstly for mechanical and corrosion-inhibiting protection for the substrate and secondly for high adhesion for the optical multilayer system.
- a lower layer may be applied to the substrate—likewise as a protection layer—on the side which is remote or opposite from the side to which the optical multilayer system is applied.
- both layers may consist of aluminium oxide, which can be produced from the anodically oxidized or electrolytically brightened and anodically oxidized substrate material.
- a further layer with a reflection-increasing action, can be applied to the substrate or to the lower layer.
- these two parts can advantageously be joined to one another (even if a layer consisting of aluminium oxide is present on the substrate) by laser welding.
- radiation from a CO 2 or Nd-YAG laser with sufficient power can be used for the welding.
- the use of laser welding has advantages over soldering.
- One advantage is that there are no unnecessary metallic interfaces (no solder).
- Another advantage is that it is possible to achieve a higher mechanical strength of the joint and, therefore, a greater resistance to vibrations and impacts.
- a further advantage is that the permissible operating temperature (steady temperature) of the absorber part according to the invention is increased. Still another advantage is that a greater operational reliability is ensured.
- the tube and the absorber part may be joined where they are in abutment with one another by spot-welded seams which run on both sides of the tube and are produced by a pulse welding process.
- weld spot dimensions are primarily dependent on the thermal conductivity, with surface temperature, irradiation time, thickness of the absorber part and type of material representing factors which influence one another. There is a proportional relationship between the fusion depth and the mean laser power.
- FIG. 1 shows an outline sectional illustration through an absorber part of a solar collector element according to the invention
- FIG. 2 shows a perspective view of an area of an embodiment of a solar collector element according to the invention.
- FIG. 3 shows a plan view of an embodiment of a solar collector element according to the invention with a meandering tube path.
- the absorber part (reference symbol 10 in FIG. 2) of the solar collector element (reference symbol E in FIG. 2) according to the invention consists of a composite material with a highly selective absorptivity and reflectivity in the solar wavelength region and in the thermal radiation region.
- This composite material for its part comprises a strip-like substrate 1 , which in particular can be deformed and consists of aluminium, an intermediate layer 2 which is applied to the substrate 1 on a side A, and an optically active multilayer system 3 which is applied to the intermediate layer 2 .
- the substrate 1 may preferably have an in particular regular rolled structure of grooves which run substantially parallel to one another in a preferred direction.
- a structure of this type if these grooves are oriented parallel to the north/south direction, enables the absorptance of a solar collector element E, according to the invention, to attain a level which is as far as possible independent of the particular angle of the sun, which changes over the course of the day.
- a total light reflectivity, determined according to DIN 5036, part 3, on side A of the optical multilayer system 3 may preferably be less than 5%.
- the composite material may preferably be processed in the form of a coil with a width of up to 1600 mm, preferably of 1250 mm, and with a thickness D of approximately 0.1 to 1.5 mm, preferably of approximately 0.2 to 0.8 mm, it being possible to produce the solar collector element E according to the invention from this coil in a simple manner by stamping out a plate-like absorber part 10 and joining it to a tube (reference symbol 11 in FIG. 2).
- the substrate 1 of the composite material may preferably have a thickness D 1 of approximately 0.1 to 0.7 mm.
- the aluminium of the substrate 1 may in particular be more than 99.0% pure, which promotes a high thermal conductivity.
- the intermediate layer 2 consists of anodically oxidized or electrolytically brightened and anodically oxidized aluminium, which is applied to the substrate material.
- the multilayer system 3 comprises three individual layers 4 , 5 , 6 , an upper and middle layers 4 , 5 being oxide layers and a bottom layer 6 being a metallic layer applied to the intermediate layer 2 .
- the top layer 4 of the optical multilayer system 3 is, preferably, a silicon oxide layer of chemical composition SiO y .
- the middle layer 5 is a chromium oxide layer of chemical composition CrO x
- the bottom layer 6 consists of gold, silver, copper, chromium, aluminium and/or molybdenum.
- the indices x, y indicate a stoichiometric or non-stoichiometric ratio of the oxidized substance to the oxygen in the oxides.
- the stoichiometric or non-stoichiometric ratio x may preferably lie in the range 0 ⁇ 3, while the stoichiometric or non-stoichiometric ratio y may adopt values in the range 1 ⁇ y ⁇ 2.
- the two upper layers 4 , 5 of the optical multilayer system 3 may be sputtered layers, in particular layers produced by reactive sputtering, CVD or PECVD layers or layers produced by vaporization, in particular by electron bombardment or from thermal sources, means that it is possible to adjust the ratios x, y continuously (i.e. to set them to non-stoichiometric values of the indices), with the result that the layer properties can in each case be varied.
- the top layer 4 of the optical multilayer system 3 may advantageously have a thickness D 4 of more than 3 nm. At this thickness D 4 , the layer is already sufficiently efficient, yet the outlay on time, material and energy is low.
- An upper limit for the layer thickness D 4 in view of these aspects, is approximately 500 nm.
- An optimum value for the middle layer 5 of the optical multilayer system 3 in view of the abovementioned aspects, is a minimum thickness D 5 of more than 10 nm and a maximum thickness D 5 of approximately 1 ⁇ m.
- the corresponding value for the bottom layer 6 is a thickness D 6 of at least 3 nm, at most approximately 500 nm.
- the bottom layer 6 of the optical multilayer system 3 should preferably be more than 99.5% pure.
- the layer may be a sputtered layer or a layer which is produced by vaporization, in particular by electron bombardment or from thermal sources, so that the entire optical multilayer system 3 advantageously comprises layers 4 , 5 , 6 which are applied in vacuum order in a continuous process.
- a lower layer 7 which—like the intermediate layer 2 —consists of anodically oxidized or electrolytically brightened and anodically oxidized aluminium, is applied to that side B of the strip-like substrate 1 which is remote from the optical multilayer system 3 .
- the intermediate layer 2 and the lower layer 7 may advantageously be produced simultaneously by wet-chemical means, in which case the pores in the aluminium oxide layer can be as far as possible closed off by hot-sealing during the final phase of the wet-chemical process sequence, resulting in a surface with long-term stability. Therefore, the lower layer 7 —like the intermediate layer 2 —offers mechanical and corrosion-inhibiting protection to the substrate 1 .
- the layer structure it is possible, in particular, for the layer structure to be assembled in such a manner that the total light reflectivity, determined in accordance with DIN 5036, part 3, on side A of the optical multilayer system 3 , under a thermal load of 430° C./100 hours, undergoes changes of less than 7%, preferably of less than 4%.
- FIG. 2 illustrates the overall structure of a solar collector element E according to the invention.
- the absorber part 10 consists of the composite material having the substrate 1 consisting of aluminium and the multilayer system 3 built up from three layers 4 , 5 , 6 , as has been explained above.
- the absorber part 10 which can be produced at low cost and in an environmentally friendly manner, results in high light absorption and dissipation of heat to the tube 11 , while, under collector operating conditions which involve high thermal loads, it is possible to ensure a comparably long service life.
- the nature of the joint between the absorber part 10 and the tube 11 (which consist in particular of copper) is produced by means of a laser welding process, in particular in the form of a pulse welding process, also contributes to the latter effect.
- Laser welding is a fusion welding process, i.e. the parts which are to be joined are melted under the action of the laser radiation.
- a particular feature is the high power density and, when using pulse welding, the rapid cooling associated with the short duration of action.
- the material-to-material bond which is formed between the two parts which are to be joined consists only of the respective materials of the absorber part 10 and of the tube 11 ; on account of the lower melting point of aluminium, drop-shaped solidified small molten balls 12 predominantly comprising aluminium are formed on the absorber part 10 , and the aluminium has diffused into the copper of the tube 11 .
- the small molten balls 12 are responsible for bridging any gap or air cushion which may be present between absorber part 10 and tube 11 .
- the power density of the laser during welding should not exceed 10 7 W/cm 2 , preferably 10 6 W/cm 2 .
- the total energy for a weld spot should be active for a time of up to approximately 10 ms, preferably distributed over the course of time.
- the actual spatial and temporal intensity distribution at the location of action should also be taken into account (spiking, hot spots).
- the tube 11 and the absorber part 10 may—as illustrated in FIG. 2—be joined where they are in contact with one another by weld seams which run on both sides of the tube 11 and are formed from welds spots (small molten balls 12 ) which are spaced apart from one another (distance a) and are in particular arranged at regular intervals.
- the heat transfer from the absorber part 10 to the tube 11 takes place predominantly at the weld spots, the size of the small molten balls 12 and the distance a between the small molten balls 12 are the decisive factors in determining the efficiency of the collector.
- the heat resistance of the absorber part 10 in its plane of extent, limits the efficiency of the collector. This heat resistance of the absorber part 10 is determined substantially by the thermal conductivity of the composite material, primarily that of the substrate 1 , on the one hand, and by the thickness D of the absorber part 10 , on the other hand.
- the optimum distance a between the small molten balls 12 for a predetermined composite material of the absorber part 10 and a fixed size (diameter d) of the small molten balls 12 , therefore depends on the thickness D of the absorber part.
- a thickness D of the absorber part of approximately 0.3 to 0.8 mm
- a diameter d of the small molten balls 12 of approximately 0.2 to 3.2 mm
- this optimum distance a (center-to-center distance of the small molten balls 12 ) is approximately 0.5 to 2.5 mm.
- the greater the thickness D of the absorber part 10 the shorter the distance a between the weld spots has to be.
- the present invention is not restricted to the exemplary embodiment which has been described, but rather encompasses all means and measures which achieve the same effect within the context of the invention.
- the bottom layer 6 of the optical multilayer system 3 it is also possible for the bottom layer 6 of the optical multilayer system 3 to comprise a plurality of partial layers of gold, silver, copper, chromium, aluminium and/or molybdenum arranged above one another.
- the top layer may alternatively also consist of fluorides or nitrides.
- copper is also eminently suitable as the substrate material, although aluminium, for approximately the same heat transfer properties, achieves a higher strength without it being necessary to provide beads.
- aluminium strip as substrate 1 , there is a wide range of different rolled surfaces available, in particular surfaces with a grooved structure, which, when used as absorber composite material, advantageously minimize and homogenise the extent to which the absorptance is dependent on the angle of the sun, given a suitable orientation.
- the tube 11 may in particular be laid in straight form or, as illustrated in FIG. 3, in meandering form on the absorber part 10 . If the tube is laid in meandering form, the welding can be restricted to straight sections I of tube, while curved sections K of tube are not welded.
- the invention is not restricted to the combination of features defined in claim 1 , but rather may also be defined by any other desired combination of specific features of all the individual features disclosed. This means that in principle virtually any individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. In this respect, claim 1 is only to be understood as an initial attempt at putting an invention into words.
Abstract
The invention relates to a solar collector element having an absorber part and a tube for a heat transfer liquid connected thereto on a first side. The absorber part consisting of a composite material having a metallic substrate and an optically active coating on a second side of the substrate. The coating is a multilayer system having three layers. The top layer is a dielectric layer, preferably an oxide, fluoride or nitride layer of chemical composition MeOz, MeFr, MeNs, having a refractive index n<1.8. The middle layer is a chromium oxide layer of chemical composition CrOx. The bottom layer is gold, silver, copper, chromium, aluminium and/or molybdenum. The indices x, z, r and s indicate a stoichiometric or non-stoichiometric ratio in the oxides, fluorides or nitrides.
Description
- The present invention relates to a solar collector element having an absorber part and having a tube for a heat-transfer liquid. The absorber part is a composite material having a metallic substrate with an optically active coating on a second side of the absorber part opposite the tube.
- It is known to use solar collectors to obtain energy from solar radiation. The solar radiation is converted into heat at an absorber part, which is in the form of a plate, for example, of a solar collector and heats a heat-transfer liquid contained in the collector. For the heat-transfer liquid, there is a circuit system composed of tubes that enables the heat which has been taken up to be released again to a consumer, such as for example to a heat exchanger, in which service water can be heated, or to heat a swimming pool.
- In general, when radiation impinges on an object—as is the case with the coated surface of an absorber part—it is split into a reflected fraction, an absorbed fraction and a transmitted fraction, which are determined by the reflectivity (reflectance), the absorptivity (absorptance) and the transmissivity (transmittance) of the object. Reflectance, absorptance and transmittance are optical properties which, depending on the wavelength of incident radiation (e.g. in the ultraviolet region, in the region of visible light, in the infrared region and in the region of thermal radiation) can adopt different values for the same material. Kirchhoff's law, according to which the absorptivity, in each case at a defined temperature and wavelength, has a constant ratio to the emittance, is known to apply to the absorptance. Therefore, Wien's displacement law and Planck's radiation law as well as the Stefan-Boltzmann law are of importance for the absorptance, describing defined relationships between radiation intensity, spectral distribution density, wavelength and temperature of a black body. Calculations should take account of the fact that the black body per se does not exist, and real substances each deviate in a characteristic way from the ideal distribution. To ensure highly effective utilization of energy, absorber parts are required to have a maximum absorptivity in the solar wavelength region (approximately 300 to approximately 2500 nm) and a maximum reflectivity in the thermal radiation region (above approximately 2500 nm).
- Absorbers for flat collectors, in which solar collector elements of the type described above with coated absorber parts that satisfy this demand for selective absorption to a high level, are known under the name Tinox. In these collectors, the material of the absorber parts comprises a copper strip substrate to which a layer of titanium oxynitride has been applied, followed by a covering layer of silicon dioxide. The tube which is connected to an absorber part likewise consists of copper and is soldered to the absorber part.
- In connection with solar collectors a distinction is drawn between low-temperature collectors, with operating temperatures of up to 100° C., and high-temperature collectors, with operating temperatures of over 100° C. In the case of tower installations, which are used to provide process heat, the absorber temperature may be up to 1200° C. The so-called steady temperature, which is to be understood as meaning the theoretically possible maximum temperature of use of a collector at which the material is in thermal equilibrium with the environment, is often referred to as a characteristic variable for a solar collector. Steady temperatures in the low-temperature range are characteristic of the Tinox absorbers described. In higher temperature ranges, for the known solar collector element with the Tinox coating or with other coatings which are known to be used, such as black paints or pigmented plastics, there is a risk of decomposition of the layer, of gases being evolved, but also of the capacity of the collector element falling at least for a relatively short time, for example on account of bleaching of the black layer.
- With regard to the joining of the absorber part and tube, it should be noted that this jointing only has to ensure the required strength, but also has to provide a sufficiently high heat transfer. In connection therewith, it should be ensured that, in the event of any desired changes in the absorber part/tube combination of materials (no longer Cu/Cu), problems do not arise with regard to finding a suitable joining technique.
- The present invention is based on the object of providing a solar collector element of the type described in the introduction which, on the one hand, leads to a high light absorption and a high reflectivity in the solar radiation region and, on the other hand, which has improved use characteristics in particular under high thermal load operating conditions, and has a longer service life, in combination with a production method that involves minimum possible capital outlay. Furthermore, the invention is also intended to allow an optimum solution to the problem with regard to ensuring a strong mechanical joint and good heat transfer between the absorber part and the tube. Finally, the solar collector element is to be distinguished by the possibility of steady temperatures within the range of use of high-temperature collectors and also by high long-term chemical stability.
- According to the invention, this is achieved by the fact that the coating comprises a multilayer system which is composed of three layers, of which the top layer is a dielectric layer, preferably an oxide, fluoride or nitride layer of chemical composition MeOz, MeFr, MeNs, having a refractive index n<1.8, and of which the middle layer is a chromium oxide layer of chemical composition CrOx, and of which the bottom layer consists of gold, silver, copper, chromium, aluminium and/or molybdenum. The indices x, z, r and s indicating a stoichiometric or non-stoichiometric ratio in the oxides, fluorides or nitrides.
- The optical multilayer system which is present according to the invention can firstly be applied advantageously, since there is no need for environmentally hazardous, in some cases toxic, salt solutions during production. For example, the metallic layer of the optical multilayer system may be a sputtered layer or a layer which is produced by vaporization, in particular by electron bombardment or from thermal sources. The two upper layers of the optical multilayer system may likewise be sputtered layers, in particular layers produced by reactive sputtering, CVD or PECVD layers or layers produced by vaporization, in particular by electron bombardment or from thermal sources, so that the entire optical multilayer system comprises layers which are applied in vacuum order, in particular in a continuous process.
- The top layer may alternatively be a silicon oxide layer of chemical composition SiOy, where the index y once again indicates a stoichiometric or non-stoichiometric ratio in the oxide composition.
- In addition to having a high long-term thermal and chemical stability, the solar collector element according to the invention is also distinguished, on account of the ease of processing, in particular deforming, the composite material from which the absorber part is produced. This is primarily achieved on account of the metallic substrate, which may be made from copper or preferably from aluminium, by a production method which involves little complexity and by a high thermal conductivity. The latter property is particularly important since it allows rapid, highly efficient transfer of the heat taken up as a result of the light absorption to the heat-transfer liquid.
- The above processes for applying the layers of the system also advantageously enable the chemical composition MeOz, MeFr, MeNs of the top layer and the chemical composition CrOx of the chromium oxide layer, with regard to the indices x, y, z, r and s, to be not only set at defined, discrete values but also allows a stoichiometric or non-stoichiometric ratio between the oxidized substance and the oxygen to be varied continuously within defined limits. In this way it is possible to specifically set, by way of example, the refractive index of the reflection-reducing top layer (which is also responsible for increasing the mechanical load-bearing capacity (DIN 58196, part 5)) and the absorptivity of the chromium oxide layer (the absorptance decreasing as the value of the index x rises).
- According to the invention, it is in this way possible to set a total light reflectivity, determined in accordance with DIN 5036,
part 3, on the side of the optical multilayer system to a preferred level of less than 5%. In addition to a high resistance to ageing, it is also possible to ensure a high thermal stability, in such a manner that under a thermal load of 430° C./100 hours, only changes of less than 7%, and preferably of less than 4%, in the reflectivity occur. Moreover, in the event of a thermal load of this nature, there is advantageously also no evolution of gases. - The composite material which is used for the absorber part according to the invention therefore, on account of its synergistic combination of properties
- of the substrate layer, for example its excellent deformability, by means of which it withstands stresses produced in the production process of the solar collector element according to the invention during the shaping processes which are to be performed without problems, for example its high thermal conductivity and—in particular in the case of aluminium as substrate material—the capacity for a surface patterning which in the light wavelength region additionally promotes adsorption and is then followed by the other layers in relief, and moreover with a reflectance in the solar radiation region which reinforces the action of the metallic layer of the optical three-layer system;
- of the metallic layer which, on account of its constituents, which have a high reflectivity and therefore a low emission in the thermal radiation region, takes account of the fact that, according to the Lambert-Bouguer law, the radiation characteristic is absorbed exponentially as the penetration depth grows, and for most inorganic substances is available as a store or thermal energy which can be passed on at even a very low depth (less than approximately 1 μm);
- of the chromium oxide layer, with its high selectivity of the absorptivity (peak values over 90% in the wavelength region from approximately 300 to 2500 nm, minimum values below 15% in the wavelength region>approx. 2500 nm) and its capacity for modification (index x) which has already been explained, and
- of the top, in particular silicon oxide, layer, the advantages of which have to some extent already been pointed out above and which, in addition to its antireflective action, also has a high transmittance and, as a result, increases the proportion of the radiation values in the solar region which can be absorbed by the chromium oxide layer;
- is eminently suitable for the production of the solar collector element according to the invention. Therefore, by using the solar collector element according to the invention, not only is it possible to produce low-temperature collectors with an operating temperature of up to 100° C., but also it is possible to produce high-temperature collectors, in which steady temperatures of over 250° C. are possible.
- Beneath the optical multilayer system, it is also possible to provide an intermediate layer on the substrate, the intermediate layer being responsible firstly for mechanical and corrosion-inhibiting protection for the substrate and secondly for high adhesion for the optical multilayer system. A lower layer may be applied to the substrate—likewise as a protection layer—on the side which is remote or opposite from the side to which the optical multilayer system is applied. In the case of an aluminium substrate, both layers may consist of aluminium oxide, which can be produced from the anodically oxidized or electrolytically brightened and anodically oxidized substrate material. In addition, a further layer, with a reflection-increasing action, can be applied to the substrate or to the lower layer.
- Preferably, in the case of an aluminium substrate material of the absorber part and a copper tube, these two parts can advantageously be joined to one another (even if a layer consisting of aluminium oxide is present on the substrate) by laser welding. This leads to a material-to-material bond as a result of melted and resolidified aluminium and as a result of migration of the aluminium into the copper. By way of example, radiation from a CO2 or Nd-YAG laser with sufficient power can be used for the welding.
- Irrespective of the combination of materials used for the absorber part/tube, the use of laser welding has advantages over soldering. One advantage is that there are no unnecessary metallic interfaces (no solder). Another advantage is that it is possible to achieve a higher mechanical strength of the joint and, therefore, a greater resistance to vibrations and impacts. A further advantage is that the permissible operating temperature (steady temperature) of the absorber part according to the invention is increased. Still another advantage is that a greater operational reliability is ensured.
- In particular, the tube and the absorber part may be joined where they are in abutment with one another by spot-welded seams which run on both sides of the tube and are produced by a pulse welding process. When determining the laser power and pulse frequency, it should be noted that the weld spot dimensions are primarily dependent on the thermal conductivity, with surface temperature, irradiation time, thickness of the absorber part and type of material representing factors which influence one another. There is a proportional relationship between the fusion depth and the mean laser power.
- Further advantageous embodiments of the invention are given in the subclaims and in the detailed description which follows.
- The invention is explained in more detail on the basis of an exemplary embodiment which is illustrated by the appended drawing, in which:
- FIG. 1 shows an outline sectional illustration through an absorber part of a solar collector element according to the invention;
- FIG. 2 shows a perspective view of an area of an embodiment of a solar collector element according to the invention; and
- FIG. 3 shows a plan view of an embodiment of a solar collector element according to the invention with a meandering tube path.
- Throughout the various figures of the drawing, identical parts are always provided with identical reference symbols and are therefore generally also in each case only described once.
- The absorber part (
reference symbol 10 in FIG. 2) of the solar collector element (reference symbol E in FIG. 2) according to the invention consists of a composite material with a highly selective absorptivity and reflectivity in the solar wavelength region and in the thermal radiation region. This composite material for its part comprises a strip-like substrate 1, which in particular can be deformed and consists of aluminium, anintermediate layer 2 which is applied to thesubstrate 1 on a side A, and an opticallyactive multilayer system 3 which is applied to theintermediate layer 2. - The
substrate 1 may preferably have an in particular regular rolled structure of grooves which run substantially parallel to one another in a preferred direction. A structure of this type, if these grooves are oriented parallel to the north/south direction, enables the absorptance of a solar collector element E, according to the invention, to attain a level which is as far as possible independent of the particular angle of the sun, which changes over the course of the day. - A total light reflectivity, determined according to DIN 5036,
part 3, on side A of theoptical multilayer system 3 may preferably be less than 5%. - The composite material may preferably be processed in the form of a coil with a width of up to 1600 mm, preferably of 1250 mm, and with a thickness D of approximately 0.1 to 1.5 mm, preferably of approximately 0.2 to 0.8 mm, it being possible to produce the solar collector element E according to the invention from this coil in a simple manner by stamping out a plate-
like absorber part 10 and joining it to a tube (reference symbol 11 in FIG. 2). Thesubstrate 1 of the composite material may preferably have a thickness D1 of approximately 0.1 to 0.7 mm. - The aluminium of the
substrate 1 may in particular be more than 99.0% pure, which promotes a high thermal conductivity. - (The
intermediate layer 2 consists of anodically oxidized or electrolytically brightened and anodically oxidized aluminium, which is applied to the substrate material. - The
multilayer system 3 comprises threeindividual layers 4, 5, 6, an upper andmiddle layers 4, 5 being oxide layers and a bottom layer 6 being a metallic layer applied to theintermediate layer 2. The top layer 4 of theoptical multilayer system 3 is, preferably, a silicon oxide layer of chemical composition SiOy. Themiddle layer 5 is a chromium oxide layer of chemical composition CrOx, and the bottom layer 6 consists of gold, silver, copper, chromium, aluminium and/or molybdenum. - The indices x, y indicate a stoichiometric or non-stoichiometric ratio of the oxidized substance to the oxygen in the oxides. The stoichiometric or non-stoichiometric ratio x may preferably lie in the range 0<×<3, while the stoichiometric or non-stoichiometric ratio y may adopt values in the
range 1≦y≦2. - The fact that the two
upper layers 4, 5 of theoptical multilayer system 3 may be sputtered layers, in particular layers produced by reactive sputtering, CVD or PECVD layers or layers produced by vaporization, in particular by electron bombardment or from thermal sources, means that it is possible to adjust the ratios x, y continuously (i.e. to set them to non-stoichiometric values of the indices), with the result that the layer properties can in each case be varied. - The top layer4 of the
optical multilayer system 3 may advantageously have a thickness D4 of more than 3 nm. At this thickness D4, the layer is already sufficiently efficient, yet the outlay on time, material and energy is low. An upper limit for the layer thickness D4, in view of these aspects, is approximately 500 nm. An optimum value for themiddle layer 5 of theoptical multilayer system 3, in view of the abovementioned aspects, is a minimum thickness D5 of more than 10 nm and a maximum thickness D5 of approximately 1 μm. The corresponding value for the bottom layer 6 is a thickness D6 of at least 3 nm, at most approximately 500 nm. - With a view to achieving high efficiency, the bottom layer6 of the
optical multilayer system 3 should preferably be more than 99.5% pure. As has already been mentioned, the layer may be a sputtered layer or a layer which is produced by vaporization, in particular by electron bombardment or from thermal sources, so that the entireoptical multilayer system 3 advantageously compriseslayers 4, 5, 6 which are applied in vacuum order in a continuous process. - A
lower layer 7 which—like theintermediate layer 2—consists of anodically oxidized or electrolytically brightened and anodically oxidized aluminium, is applied to that side B of the strip-like substrate 1 which is remote from theoptical multilayer system 3. Theintermediate layer 2 and thelower layer 7 may advantageously be produced simultaneously by wet-chemical means, in which case the pores in the aluminium oxide layer can be as far as possible closed off by hot-sealing during the final phase of the wet-chemical process sequence, resulting in a surface with long-term stability. Therefore, thelower layer 7—like theintermediate layer 2—offers mechanical and corrosion-inhibiting protection to thesubstrate 1. - According to the invention it is possible, in particular, for the layer structure to be assembled in such a manner that the total light reflectivity, determined in accordance with DIN 5036,
part 3, on side A of theoptical multilayer system 3, under a thermal load of 430° C./100 hours, undergoes changes of less than 7%, preferably of less than 4%. - FIG. 2 illustrates the overall structure of a solar collector element E according to the invention. The drawing diagrammatically depicts the
absorber part 10 and the tube 11 (for a heat-transfer liquid) as parts of the solar collector element E. Theabsorber part 10 consists of the composite material having thesubstrate 1 consisting of aluminium and themultilayer system 3 built up from threelayers 4, 5, 6, as has been explained above. Theabsorber part 10, which can be produced at low cost and in an environmentally friendly manner, results in high light absorption and dissipation of heat to thetube 11, while, under collector operating conditions which involve high thermal loads, it is possible to ensure a comparably long service life. - The nature of the joint between the
absorber part 10 and the tube 11 (which consist in particular of copper) is produced by means of a laser welding process, in particular in the form of a pulse welding process, also contributes to the latter effect. Laser welding is a fusion welding process, i.e. the parts which are to be joined are melted under the action of the laser radiation. A particular feature is the high power density and, when using pulse welding, the rapid cooling associated with the short duration of action. Since the laser welding of theabsorber part 10 to thetube 11 is preferably carried out without filler, the material-to-material bond which is formed between the two parts which are to be joined consists only of the respective materials of theabsorber part 10 and of thetube 11; on account of the lower melting point of aluminium, drop-shaped solidified smallmolten balls 12 predominantly comprising aluminium are formed on theabsorber part 10, and the aluminium has diffused into the copper of thetube 11. The smallmolten balls 12 are responsible for bridging any gap or air cushion which may be present betweenabsorber part 10 andtube 11. To produce an optimum joint, the power density of the laser during welding, taking account of the criteria listed above, should not exceed 107 W/cm2, preferably 106 W/cm2. The total energy for a weld spot should be active for a time of up to approximately 10 ms, preferably distributed over the course of time. As well as the criteria which have already been listed, the actual spatial and temporal intensity distribution at the location of action should also be taken into account (spiking, hot spots). - In particular, the
tube 11 and theabsorber part 10 may—as illustrated in FIG. 2—be joined where they are in contact with one another by weld seams which run on both sides of thetube 11 and are formed from welds spots (small molten balls 12) which are spaced apart from one another (distance a) and are in particular arranged at regular intervals. - Since, when a solar collector is operating, the heat transfer from the
absorber part 10 to thetube 11 takes place predominantly at the weld spots, the size of the smallmolten balls 12 and the distance a between the smallmolten balls 12 are the decisive factors in determining the efficiency of the collector. On the other hand, the heat resistance of theabsorber part 10, in its plane of extent, limits the efficiency of the collector. This heat resistance of theabsorber part 10 is determined substantially by the thermal conductivity of the composite material, primarily that of thesubstrate 1, on the one hand, and by the thickness D of theabsorber part 10, on the other hand. The optimum distance a between the smallmolten balls 12, for a predetermined composite material of theabsorber part 10 and a fixed size (diameter d) of the smallmolten balls 12, therefore depends on the thickness D of the absorber part. In the case of asubstrate 1 made from aluminium, a thickness D of the absorber part of approximately 0.3 to 0.8 mm, and a diameter d of the smallmolten balls 12 of approximately 0.2 to 3.2 mm, this optimum distance a (center-to-center distance of the small molten balls 12) is approximately 0.5 to 2.5 mm. The greater the thickness D of theabsorber part 10, the shorter the distance a between the weld spots has to be. - The present invention is not restricted to the exemplary embodiment which has been described, but rather encompasses all means and measures which achieve the same effect within the context of the invention. For example, it is also possible for the bottom layer6 of the
optical multilayer system 3 to comprise a plurality of partial layers of gold, silver, copper, chromium, aluminium and/or molybdenum arranged above one another. - As has already been mentioned, the top layer may alternatively also consist of fluorides or nitrides. As is known, copper is also eminently suitable as the substrate material, although aluminium, for approximately the same heat transfer properties, achieves a higher strength without it being necessary to provide beads.
- With aluminium strip as
substrate 1, there is a wide range of different rolled surfaces available, in particular surfaces with a grooved structure, which, when used as absorber composite material, advantageously minimize and homogenise the extent to which the absorptance is dependent on the angle of the sun, given a suitable orientation. - Furthermore, the person skilled in the art can supplement the invention by means of additional advantageous measures without departing from the scope of the invention. For example, the
tube 11 may in particular be laid in straight form or, as illustrated in FIG. 3, in meandering form on theabsorber part 10. If the tube is laid in meandering form, the welding can be restricted to straight sections I of tube, while curved sections K of tube are not welded. - Furthermore, the invention is not restricted to the combination of features defined in
claim 1, but rather may also be defined by any other desired combination of specific features of all the individual features disclosed. This means that in principle virtually any individual feature ofclaim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. In this respect,claim 1 is only to be understood as an initial attempt at putting an invention into words.
Claims (43)
1. Solar collector element comprising an absorber part and a tube adapted to contain a heat-transfer liquid, the tube being connected to the absorber part on a first side, the absorber part being a composite material having a metallic substrate and having an optically active coating on the substrate on a second side (A), the coating further comprising a multilayer system having three layers, the top layer being a dielectric layer having a refractive index n<1.8, the middle layer being a chromium oxide layer of chemical composition CrOx, and the bottom layer being of a material selected from the group consisting of gold, silver, copper, chromium, aluminium and molybdenum, the index x indicates a stoichiometric or non-stoichiometric ratio.
2. Solar collector element according to claim 1 , wherein the top layer is a silicon oxide layer of chemical composition SiOy, the index y indicating a stoichiometric or non-stoichiometric ratio.
3. Solar collector element according to claim 1 wherein the top layer is of a chemical composition selected from the group consisting of MeOz, MeFr and MeNs the indices z, r and s indicating a stoichiometric and non-stoichiometric ratio.
4. Solar collector element according to claim 1 wherein an intermediate layer is applied to the substrate beneath the multilayer system.
5. Solar collector element according to claim 1 wherein a lower layer is applied to the substrate on the first side thereof.
6. Solar collector element according to claim 1 wherein the substrate is formed of aluminium.
7. Solar collector element according to claim 6 wherein the aluminium is more than 99.0% pure.
8. Solar collector element according to claim 4 wherein the intermediate layer is formed of anodically oxidized aluminium.
9. Solar collector element according to claim 4 wherein the intermediate layer is formed of electrolytically brightened and anodically oxidized aluminium.
10. Solar collector element according to claim 5 wherein the lower layer is formed of anodically oxidized aluminium.
11. Solar collector element according to claim 5 wherein the lower layer is formed of electrolytically brightened and anodically oxidized aluminium.
12. Solar collector element according to claim 1 wherein the substrate has a rolled structure of grooves which run substantially parallel to one another in a preferred direction.
13. Solar collector element according to claim 1 wherein the substrate is formed of copper.
14. Solar collector element according to claim 1 wherein the stoichiometric or non-stoichiometric ratio x lies in the range 0<×<3.
15. Solar collector element according to claim 2 wherein the stoichiometric or non-stoichiometric ratio y lies in the range 1≦y≦2.
16. Solar collector element according to claim 1 wherein the bottom layer includes a plurality of partial layers, arranged one above the other and be formed of at least one material selected from the group of gold, silver, copper, chromium, aluminium and molybdenum.
17. Solar collector element according to claim 1 wherein at least one of the top and middle layers are sputtered layers.
18. Solar collector element according to claim 17 wherein the layers are produced by reactive sputtering.
19. Solar collector element according to claim 1 wherein at least one of the top and middle layers are produced by vaporization.
20. Solar collector element according to claim 19 wherein vaporization is by electron bombardment.
21. Solar collector element according to claim 19 wherein the vaporization is by thermal sources.
22. Solar collector element according to claim 1 wherein at least one of the upper and middle layers are CVD layers.
23. Solar collector element according to claim 1 wherein at least one of the upper and middle layers are PECVD layers.
24. Solar collector element according to claim 1 wherein the bottom layer is a sputtered layer.
25. Solar collector element according to claim 1 wherein the bottom layer is a layer produced by vaporization.
26. Solar collector element according to claim 25 wherein vaporization is by electron bombardment.
27. Solar collector element according to claim 25 wherein vaporization is from thermal sources.
28. Solar collector element according to claim 1 wherein the multilayer system is applied in vacuum order in a continuous process.
29. Solar collector element according to claim 1 wherein the top layer has a thickness in the range of 3 nm to about 500 nm.
30. Solar collector element according to claim 1 wherein the middle layer has a thickness in the range of 10 nm to about 1 μm.
31. Solar collector element according to claim 1 wherein the bottom layer of the optical multilayer system has a thickness (D6) of at least 3 nm and at most approximately 500 nm.
32. Solar collector element according to claims 1 wherein a total light reflectivity on second side is less than 5%.
33. Solar collector element according to claim 1 wherein a total light reflectivity on the second side under a thermal load of 430° C./100 hours undergoes changes of less than 7%.
34. Solar collector element according to claim 33 wherein the change is less than 4%.
35. Solar collector element according to claim 1 wherein the absorber part is of plate-like form and has a thickness in the range of 0.1 to about 1.5 mm.
36. Solar collector element according to claim 35 wherein the thickness is in the range of about 0.2 to about 0.8 mm.
37. Solar collector element according to claim 1 wherein the tube is formed of copper.
38. Solar collector element according to claim 1 wherein the absorber part and the tube are connected to one another by means of a material-to-material laser welded bond.
39. Solar collector element according to claim 38 wherein the bond is formed by a pulse welding process.
40. Solar collector element according to claim 38 wherein the bond between the absorber part and the tube is made up of only of the respective materials of the absorber part and of the tube.
41. Solar collector element according to claim 24 wherein the absorber part and the tube with the absorber part having a substrate made from aluminium and the tube is formed of copper, is formed by a series of molten balls which have solidified on the absorber part and predominantly made up of aluminium and by diffusion of the aluminium into the copper of the tube.
42. Solar collector element according to claim 24 wherein the tube and the absorber part are joined where they are in abutment with one another by weld seams running on both sides of the tube and are formed from weld spots which are spaced apart from one another.
43. Solar collector element according to claim 41 wherein the tube and the absorber part, with the absorber part having a thickness in the range of about 0.3 to about 0.8 mm and a diameter of the molten balls in the range of about 0.2 to about 3.2 mm spaced at a distance in the range of about 0.5 to about 2.5 mm between centers of the molten balls.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE20021644U DE20021644U1 (en) | 2000-12-20 | 2000-12-20 | Solar collector element |
DE20021644.9 | 2000-12-20 |
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EP (1) | EP1217315B1 (en) |
CN (1) | CN1368627A (en) |
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DE (2) | DE20021644U1 (en) |
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ES (1) | ES2232557T3 (en) |
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US20090139514A1 (en) * | 2007-11-01 | 2009-06-04 | Acktar Ltd. | Improved Solar Collector |
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US20100057068A1 (en) * | 2008-08-29 | 2010-03-04 | Kwangyeol Lee | Gold nanostructure and methods of making and using the same |
US20100065958A1 (en) * | 2005-11-10 | 2010-03-18 | Hynix Semiconductor Inc. | Pad redistribution chip for compactness, method of manufacturing the same, and stacked package using the same |
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Publication number | Priority date | Publication date | Assignee | Title |
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3990784A (en) * | 1974-06-05 | 1976-11-09 | Optical Coating Laboratory, Inc. | Coated architectural glass system and method |
US4246892A (en) * | 1978-05-17 | 1981-01-27 | Waiche Meir R | Solar energy collector panel |
US4343533A (en) * | 1980-12-31 | 1982-08-10 | Dow Corning Corporation | Solar radiation reflector with a cellulosic substrate and method of making |
US4777936A (en) * | 1982-09-08 | 1988-10-18 | Sharp Kabushiki Kaisha | Selective absorption film of a solar heat collector |
US5004308A (en) * | 1990-05-23 | 1991-04-02 | Rockwell International Corporation | Rugate reflector |
US5730852A (en) * | 1995-09-25 | 1998-03-24 | Davis, Joseph & Negley | Preparation of cuxinygazsen (X=0-2, Y=0-2, Z=0-2, N=0-3) precursor films by electrodeposition for fabricating high efficiency solar cells |
US6234166B1 (en) * | 1999-06-30 | 2001-05-22 | Acktar Ltd. | Absorber-reflector for solar heating |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4334523A (en) * | 1980-06-23 | 1982-06-15 | Owens-Illinois, Inc. | Solar energy collector having solar selective coating of low reflectance |
US4416916A (en) * | 1982-03-04 | 1983-11-22 | Engelhard Corporation | Thin film solar energy collector |
DE3308790C2 (en) * | 1982-05-27 | 1984-08-02 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Process for the production of a selectively absorbing layer for solar collectors |
JPS58224261A (en) * | 1982-06-22 | 1983-12-26 | Toshiba Corp | Manufacture of solar heat collecting plate |
US4582764A (en) * | 1982-09-24 | 1986-04-15 | Energy Conversion Devices, Inc. | Selective absorber amorphous alloys and devices |
EP0107412B1 (en) * | 1982-10-08 | 1987-12-09 | The University Of Sydney | Solar selective surface coating |
JPS60216148A (en) * | 1984-04-11 | 1985-10-29 | Fuji Electric Corp Res & Dev Ltd | Solar heat collector |
DE19721657A1 (en) * | 1997-05-23 | 1998-12-10 | Nova Solar Gmbh | Heat exchanger for solar collectors for heating and cooling systems |
-
2000
- 2000-12-20 DE DE20021644U patent/DE20021644U1/en not_active Expired - Lifetime
-
2001
- 2001-11-24 ES ES01127975T patent/ES2232557T3/en not_active Expired - Lifetime
- 2001-11-24 AT AT01127975T patent/ATE288057T1/en active
- 2001-11-24 DK DK01127975T patent/DK1217315T3/en active
- 2001-11-24 PT PT01127975T patent/PT1217315E/en unknown
- 2001-11-24 EP EP01127975A patent/EP1217315B1/en not_active Expired - Lifetime
- 2001-11-24 DE DE50105189T patent/DE50105189D1/en not_active Expired - Lifetime
- 2001-12-20 US US10/029,493 patent/US20020073988A1/en not_active Abandoned
- 2001-12-20 CN CN01143349A patent/CN1368627A/en active Pending
-
2003
- 2003-02-27 HK HK03101467.9A patent/HK1049366A1/en unknown
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3990784A (en) * | 1974-06-05 | 1976-11-09 | Optical Coating Laboratory, Inc. | Coated architectural glass system and method |
US4246892A (en) * | 1978-05-17 | 1981-01-27 | Waiche Meir R | Solar energy collector panel |
US4343533A (en) * | 1980-12-31 | 1982-08-10 | Dow Corning Corporation | Solar radiation reflector with a cellulosic substrate and method of making |
US4777936A (en) * | 1982-09-08 | 1988-10-18 | Sharp Kabushiki Kaisha | Selective absorption film of a solar heat collector |
US5004308A (en) * | 1990-05-23 | 1991-04-02 | Rockwell International Corporation | Rugate reflector |
US5730852A (en) * | 1995-09-25 | 1998-03-24 | Davis, Joseph & Negley | Preparation of cuxinygazsen (X=0-2, Y=0-2, Z=0-2, N=0-3) precursor films by electrodeposition for fabricating high efficiency solar cells |
US6234166B1 (en) * | 1999-06-30 | 2001-05-22 | Acktar Ltd. | Absorber-reflector for solar heating |
Cited By (26)
Publication number | Priority date | Publication date | Assignee | Title |
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Also Published As
Publication number | Publication date |
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DE50105189D1 (en) | 2005-03-03 |
EP1217315B1 (en) | 2005-01-26 |
HK1049366A1 (en) | 2003-05-09 |
DE20021644U1 (en) | 2002-05-02 |
DK1217315T3 (en) | 2005-05-09 |
CN1368627A (en) | 2002-09-11 |
PT1217315E (en) | 2005-03-31 |
EP1217315A1 (en) | 2002-06-26 |
ATE288057T1 (en) | 2005-02-15 |
ES2232557T3 (en) | 2005-06-01 |
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