Classifications

• • 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
  • F24S10/73—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits the tubular conduits being of plastic material
• • 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
  • F24S10/50—Solar heat collectors using working fluids the working fluids being conveyed between plates
  • F24S10/501—Solar heat collectors using working fluids the working fluids being conveyed between plates having conduits of plastic material
• • 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
  • F24S10/80—Solar heat collectors using working fluids comprising porous material or permeable masses directly contacting the working fluids
• • 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 invention relates to a solar-powered radiation collector of thermoplastic material and a method for its production.
• Air collectors also called solar air heaters are radiant heat exchanger with which z.
• solar hot air collectors are predominantly manufactured with absorbers made of aluminum or other metals.
• the reason for this is the good conductivity of metals, because due to the low heat transfer of air to a flat surface, the solar heat in hot air collectors must be distributed over a large surface area (e.g., fins on the rear of the absorber).
• Absorbers with perforation and boundary layer extraction have two advantages over backflow absorbers: First, the perforation causes a significant improvement in the heat transfer from the absorber to the air; secondly, suction prevents convection in the collector, drastically reducing thermal losses from the absorber to the glazing, and eliminating the need for a well-cooled absorber (ie having high heat transfer coefficient from the absorber to the air) to achieve high efficiency , In absorbers for boundary layer extraction so the heat conduction in the absorber plays a minor role in terms of the efficiency of the collector. Extremely thin absorbers or absorbers with low thermal conductivity can therefore be used.
• a disadvantage of the known from the prior art air collectors is the relatively high weight of the absorber, the frame and the cover, since they are made of metal.
• the object of the invention is therefore to provide a radiation collector made of thermoplastic material, which comparatively simple, i. with little technical effort, can be produced, and a method for its production.
• the invention relates to a radiation collector at least comprising a multi-wall sheet based on thermoplastic material comprising a first, second and third Horizontal web, which are interconnected by vertical webs, wherein the first horizontal web is transparent and the second horizontal web, which is arranged between the first and third horizontal web, radiation-absorbing and is provided with holes.
• a radiation collector which is characterized in that the horizontal webs and the vertical webs form at least two superimposed rows of juxtaposed chambers, which are separated from each other and can flow through the heat transfer gas, in particular air.
• the superimposed chambers are interconnected by a plurality of holes.
• a particularly preferred radiation collector is characterized in that the chambers are closed at their ends and the chambers located above the second horizontal web have at least one inlet for a heat carrier gas and the chambers located under the second horizontal web at least one outlet for heated heat transfer gas.
• a further preferred variant of the radiation collector is characterized in that the chambers are connected to a fan, which may be arranged in a pumping circulation, and in particular a heat exchanger is connected downstream of the outlet of the chambers.
• the chambers preferably have a cross-sectional area of 0.25 to 3600 mm 2 .
• the horizontal webs are also sometimes referred to simply as straps and the vertical webs simply as webs.
• Another object of the invention is a method for producing the radiation collector according to the invention, wherein in a first step by coextrusion of a transparent and a radiation-absorbing plastic a Mehrfachstegplatte having at least a first, second and third horizontal web, which are interconnected by vertical webs, is formed, the second Horizontal web contains the radiation-absorbing plastic and in the second step, a laser beam is directed through the first horizontal bar on the second horizontal bar and the second horizontal bar is perforated by means of the laser beam and provided with a plurality of holes.
• the new radiation collector consists z. B. from a multiple web plate.
• Multiple web plates are well known in the art.
• the preferably used multiple web plate has at least three, preferably arranged parallel to each other, horizontal webs.
• the horizons zontalstege are interconnected by preferably arranged perpendicularly to vertical webs'.
• the vertical webs are preferably arranged parallel to one another. In this way, at least two superposed layers of juxtaposed, cuboidal chambers, which are traversed by the operation of the radiation collector of air or other gas.
• the horizontal webs and vertical webs may be the same or different thickness. They have a thickness of preferably 0.2 to 2 mm.
• the second horizontal web is designed in the region of the perforations (eg laser perforation) with wall thicknesses of preferably 0.2 to 0.5 mm.
• the vertical webs have a height of 3 to 50 mm.
• the height of the vertical webs determines the height of the chambers, which can be made equal or different levels.
• the vertical webs are preferably lower towards the center of the multiple web plate than in the edge regions of the web plate, in order to minimize their own shading in the case of lateral solar radiation.
• the diameter of the holes of the absorbing layer of the radiation collector is preferably 0.1 to 1.2 mm, more preferably 0.2 to 0.5 mm.
• the first horizontal bar is transparent to the radiation to be absorbed.
• the transmittance in the wavelength range of 400 to 1300 nm is preferably at least 60%.
• the transparent horizontal bar faces the sun.
• the sunlight falls through the first horizontal bar on the second horizontal bar, which forms the absorber surface.
• the second horizontal ridge which is disposed between the first and third horizontal ridge, is radiation absorbing, i. in particular it has an absorption capacity of at least 80% in the wavelength range from 400 to 2500 nm.
• the second horizontal web with a comparatively high absorption capacity must be able to absorb as much sunlight as possible during operation of the radiation collector.
• the second horizontal web is colored and / or coated, for example, with a black compound.
• a black color of the second horizontal bar can be achieved, for example, by printing with black paint, coating with black chrome or black aluminum or by direct coloring of the plastic composition with suitable colorants, preferably carbon black.
• the second horizontal web is also referred to below as the absorber surface.
• the partial transparency of the second horizontal ridge of up to 20% in the visible wavelength range can be achieved by a compound with or without high reflectivity in the infrared wavelength range or in combination, for example in the form of an additional layer, can be achieved with such a compound.
• the radiation collector is then also suitable as a partially transparent glazing element, e.g. in a building envelope.
• the second horizontal ridge has a selective absorber layer on the side facing the sun during operation.
• the second horizontal bar coated with one or more compounds which have a reflectivity of at least 70% in the infrared wavelength range. If the second horizontal bar is colored black and / or additionally carries a coating of a black compound, the compound with high reflectivity in the infrared wavelength range can be largely transparent to visible light. Examples of such compounds are indium tin oxide (ITO), zinc oxide (ZnO) and tin oxide (SnO).
• ITO indium tin oxide
• ZnO zinc oxide
• SnO tin oxide
• the infrared wavelength range is understood to be the wavelength range above 800 nm.
• the second horizontal bar is perforated.
• the proportion of the hole area on the total area of the second horizontal ridge is in particular at most 3%, preferably at most 1%, particularly preferably 0, 1 to 0.4%.
• the third horizontal web may be transparent or absorbent, for example colored and / or coated. During operation of the radiation collector, it is turned away from the sun.
• further layers of adjacent chambers may be provided.
• further horizontal webs are provided, which in turn are connected via vertical webs.
• a fourth horizontal web can be arranged below the third horizontal web. This creates a third layer of adjacent chambers. This third layer faces away from the sun during operation of the radiation collector.
• the chambers of this third layer serve as isolation chambers.
• the multiple web plate is particularly open on two opposite sides, i. the two perpendicular to the horizontal and vertical webs surfaces are not limited. In this way it is possible to flow through the chambers of the multiple web plate with gas.
• the two other, opposite sides complete with vertical webs and are therefore not open.
• the multiple web plate may be provided with a groove-spring system on the two non-open sides, as described for example in DE10 304 536 A and in WO 2004/070287.
• the chambers of the first layer between the first and the second horizontal web are facing the sun. They are also referred to below as absorption chambers.
• the chambers of the second layer between the second and the third horizontal web are facing away from the sun. They are also referred to below as collection chambers.
• the chambers of both layers are filled with heat carrier gas or flowed through by gas.
• the gas is air.
• other gases or mixtures of different gases can be used, for example, those having a higher Have heat capacity as air such as argon.
• Cold gas (temperature in the range of -10 to -30 0 C) is introduced into the sunlit absorption chambers. From there, the gas passes through the perforations of the second horizontal bar in the voltage applied to the back of the collecting chambers. When passing through the perforations, the gas heats up. The heated gas flows out of the collection chambers.
• the multiple web plate of the radiation collector according to the invention is made of thermoplastic material.
• suitable transparent, thermoplastic plastics are polycarbonates, polymethyl methacrylate, polystyrene, polyethylene, polyethylene terephthalate, polyvinyl chloride and thermoplastic polyurethane.
• suitable transparent, thermoplastic plastics are polycarbonates, polymethyl methacrylate, polystyrene, polyethylene, polyethylene terephthalate, polyvinyl chloride and thermoplastic polyurethane.
• suitable transparent, thermoplastic plastics are polycarbonates, polymethyl methacrylate, polystyrene, polyethylene, polyethylene terephthalate, polyvinyl chloride and thermoplastic polyurethane.
• ABS acrylonitrile-butadiene-styrene
• thermoplastic polyurethane or Blends of polycarbonate and ABS.
• a laser beam is directed through the first horizontal web on the second horizontal web, which is perforated by means of the laser beam.
• the wavelength of the laser beam is preferably in the range of 800 to 1200 nm.
• Suitable lasers are, for example, diode lasers or Nd: Yag lasers. Accordingly, the transparency of the first horizontal ridge must be so large that the laser beam penetrates it substantially unhindered.
• the laser beam is first absorbed by the second horizontal bar.
• the energy of the laser locally burns the material of the second horizontal bar, creating a hole.
• the laser energy is preferably 10 to 100 W.
• a plurality of holes can be produced in the second horizontal bar. This can be done serially or sequentially.
• the upper layer of the chambers between the first and second horizontal web is acted upon by compressed air from one of the two open sides of the multiple web plate.
• the resulting gas flow through the chambers, the combustion residues are blown out in the laser irradiation, so that they can not settle on the walls of the multi-wall plate.
• the method according to the invention is preferably carried out directly after the extrusion of the multiple web plate, so that the extrusion and the perforation of the multi-web plate take place in one operation.
• a series of laser beams is arranged behind the extrusion die in such a way that the laser beams are directed through the first horizontal web to the second horizontal web when the multiple web plate exits the extrusion die.
• Fig. 1 is a side view with a cross section through a collector according to the invention
• Fig. 2 is a schematic representation of the operation of the collector of FIG. 1 with
• FIG. 1 shows a multiple web plate 10 with a first, second and third horizontal web 11,
• the first horizontal web 11 is transparent. As a result, laser beams 20 through the first
• Horizontal web 11 are directed through the second horizontal web 12. The direction of the
• Laser beams are indicated in Fig. 1 by the arrows 20.
• the laser beams 20 penetrate the first horizontal web 11 and are absorbed by the second horizontal web 12, which is colored with soot, for example, whereby holes 1 are formed.
• Such a multiple web plate was used as a solar-powered radiation collector with a first horizontal web 11 (ie, a sun facing, transparent horizontal web) made of polycarbonate (Makrolon DP 1-1853 Fa. Bayer MaterialScience AG, Germany), which with an outer UV protective layer Makrolon DP 1-1816 (Bayer MaterialScience AG, Germany), a second horizontal bar 12 (ie an absorber surface) of non-transparent Makrolon 9415 (Bayer MaterialScience AG, Germany). The absorber surface was colored with carbon black.
• the perforation of the absorber surface was carried out with a Nd: Yag laser at a wavelength of 1064 nm.
• the proportion of the holes 1 in the total area was 0.1%, wherein the holes 1 were made with a diameter of 0.3 to 1 mm.
• Fig. 2 demonstrates the use of the radiation collector of FIG. 1 as a solar collector with the heat carrier air.
• the solar radiation 2 passes through the transparent first horizontal web 11 on the second horizontal web 12, which serves as an absorber. This creates heat.
• air is transported through the inlet 3 into the collector via a suction device 5 and passed through the collector so as to be passed through the laser perforation (holes 1) and transported to the outlet 4.
• the chambers 8, 8a must be closed at the terminals 9 and 9a.
• an air-pumping circuit 6, which may be open or closed, and which supplies heated air to a heat user 7, is created.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Sustainable Development (AREA)
• Physics & Mathematics (AREA)
• Sustainable Energy (AREA)
• Thermal Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Dispersion Chemistry (AREA)
• Laminated Bodies (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Nonwoven Fabrics (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2004
  • 2004-12-22 DE DE102004061712A patent/DE102004061712A1/de not_active Withdrawn
• 2005
  • 2005-12-13 CN CNA2005800444020A patent/CN101087980A/zh active Pending
  • 2005-12-13 EP EP05824071A patent/EP1831614A1/de not_active Withdrawn
  • 2005-12-13 WO PCT/EP2005/013339 patent/WO2006072369A1/de not_active Ceased
  • 2005-12-13 JP JP2007547261A patent/JP2008524549A/ja not_active Withdrawn
  • 2005-12-20 US US11/313,035 patent/US20060130827A1/en not_active Abandoned

Non-Patent Citations (1)

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