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
  • F24S10/75—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits with enlarged surfaces, e.g. with protrusions or corrugations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S80/00—Details, accessories or component parts of solar heat collectors not provided for in groups F24S10/00-F24S70/00
  • F24S80/30—Arrangements for connecting the fluid circuits of solar collectors with each other or with other components, e.g. pipe connections; Fluid distributing means, e.g. headers
• • 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 method for ensuring optimal heat exchange within an assembly consisting of a thermally conductive absorbent plate and a heat transfer fluid flowing in at least one thermally conductive tabular duct. It applies in particular but not exclusively to the collectors of thermal solar panels.
• a plate generally made of copper or aluminum, the upper face of which is coated with a selective layer favoring the absorption of sunlight; • pipes having a cross-section which are welded to the underside of said plate, these pipes generally being made of copper or aluminum;
• the heat transmission from the wall of a pipe to the heat transfer liquid is optimal when the temperature difference between said wall and the heat transfer liquid is large or, in the vicinity from the wall, the temperature of the heat transfer liquid is close to that of this wall;
• the flow of the heat transfer liquid in the pipes is laminar and the temperature distribution is not uniform indeed, the temperature of the heat transfer liquid decreases from the upper layers located near the wall of a pipe towards the center liquid therefore, the heat exchanges within the heat transfer liquid and between the pipes and the heat transfer liquid are not optimal.
• the object of the invention is therefore more particularly to eliminate these drawbacks by proposing a method making it possible to optimize the heat exchanges:
• a method for optimizing the heat exchanges between a thermally conductive absorbent plate exposed to heat radiation and a heat transfer fluid circulating in at least one thermally conductive tabular duct in thermal contact with said plate as well as within heat transfer fluid characterized in that, in order to promote heat exchange, it consists in using zones of said plate to constitute a part of the wall of said duct so that the heat transfer fluid is in direct contact with said plate way to reduce the thermal resistance between the absorbent plate and the heat transfer liquid circulating inside said conduit.
• the conduits can be arranged on the two faces of the plate, they can then communicate with each other by means of orifices making it possible to create sinuous paths thus forcing the heat-transfer liquid to sudden changes in direction during its passage through these orifices. which accentuates the turbulence and ensures stirring of the heat transfer liquid thereby promoting uniformity of temperatures and reduction of the laminar effect.
• a material absorbing the heat radiation can be applied to one of the two faces of said plate as well as possibly to the external walls of said conduits located on this face.
• the conduits may be arranged in particular on said plate "in harp” or in "serpentine".
• the conduits may consist of profiled elements having a longitudinal central concavity bordered by two opposite lateral wings which extend substantially in the same plane, these two lateral wings being fixed with sealing on one face of the plate.
• the concavities of these profiled elements may be closed at their ends by convex transverse walls provided with a flange which extends in the above-mentioned plane, in line with the above-mentioned lateral wings.
• the fixing of the conduits on the plate at the level of said lateral wings advantageously makes it possible to extend the zone of direct contact between a conduit and the plate, thus optimizing the thermal conduction.
• Figure 1 is a sectional view of an assembly arranged according to the implementation of the method according to the invention and comprising a plate on which are fixed tabular conduits.
• Figure 2 is a sectional view showing the circulation of fluids within an assembly of the above type which is constituted by a plate and tabular conduits.
• Figure 3 is a sectional view showing the circulation of fluids within an assembly of the above type consisting of a plate on which the tabular conduits are arranged in a serpentine.
• Figure 4 is a schematic view of an assembly of the above type comprising a plate on which the conduits are arranged in a coil.
• Figure 5 is a schematic view of an assembly of the above type comprising a plate on which the conduits are arranged in a harp.
• the method according to the invention consists in arranging on a thermally conductive absorbent plate 1 thermally conductive tabular conduits 2 in which circulate a heat transfer fluid 3 (shown schematically in Figures 2 and 3 by arrows), the arrangement of tabular conduits 2 on the plate 1 is made in such a way that zones of the plate 1 constitute a part of the wall of the said conduits 2 so as to allow the heat transfer fluid 3 to be in direct contact with the said plate 1 thus reducing the thermal resistance between the plate 1 and the heat transfer liquid 3 circulating inside said conduits 2.
• each tubular conduit 2 may consist of a profiled element 10 having a longitudinal central concavity 11 bordered by two opposite lateral wings 12 which extend substantially in the same plane, these two lateral wings 12 being fixed with sealing on one side of the plate 1.
• the fixing of the conduits 2 on the plate 1 at the level of the lateral wings 12 advantageously makes it possible to extend the zone of direct contact between each conduit 2 and the plate 1, thus optimizing the thermal conduction.
• the fixing of the conduits 2 on the plate 1 which takes place at the level of the lateral wings 12 can be carried out in particular by welding or by brazing or by gluing.
• the conduits 2 may be arranged on both sides of the plate 1 in this case, the plate 1 will include orifices 4 facing which will be arranged the ends of the conduits 2 in this way, the heat transfer liquid 3 circulating in the conduits 2 will be forced to sudden changes of direction during its passage through the orifices 4 which will accentuate the turbulence and ensure mixing of said liquid 3 favoring this so the temperature uniformity and the reduction of the laminar effect.
• the concavities 11 of the profiled elements 10 can be closed at their ends by convex transverse walls 13 provided with a flange 14 which extends in the plane of the lateral wings 12, in their extension.
• the conduits 2 may be arranged in particular on said plate 1: • In the manner of harps: as illustrated in FIG. 5, the conduits 2 are placed parallel, at equal distances, on one face of the said plate 1.
• One of the ends of each of the conduits 2 communicates via the 'through an orifice 4 of the above type with a single intake duct 6 formed by a profile which extends at right angles to the other face of the plate 1, the other end of each of the ducts 2 communicates by by means of an orifice 4 of the aforementioned type with an outlet duct 6 ′ constituted by a profile which extends at right angles to the other face of the plate 1.
• the intake duct 6 distributes the heat transfer liquid 3 in the heat exchange ducts 2, during their passage through these ducts 2, the heat transfer liquid 3 absorbs the calories stored by the plate 1 under the effect of solar radiation, a once heated, this heat transfer fluid 3 is recovered for a u use by the outlet manifold 6 '.
• conduits 2 are placed two by two almost parallel on one face of the plate 1, these conduits 2 being connected by junction conduits 2 'arranged transversely on the other face of the plate 1 and with which they communicate via orifices 4 of the aforementioned type thus, the heat-transfer liquid which circulates in the conduits 2 will be forced to sudden changes of direction during its passage in the junction conduits 2 'which will make it possible to accentuate turbulence within this liquid 3.
• a material absorbing heat radiation can be applied to one of the two faces of said plate 1 as well as possibly on the external walls of said conduits 2 located on this face.
• the absorbent plate 1 will preferably be made of copper or aluminum.
• the conduits 2 will have a thickness of between 0.2 and 0.3 millimeters and will be made of copper.

Landscapes

• 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)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Sorption Type Refrigeration Machines (AREA)
• Road Signs Or Road Markings (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2005
  • 2005-03-21 FR FR0502752A patent/FR2883364B1/fr not_active Expired - Fee Related
• 2006
  • 2006-03-20 CN CNA2006800139639A patent/CN101166940A/zh active Pending
  • 2006-03-20 US US11/909,352 patent/US8136583B2/en not_active Expired - Fee Related
  • 2006-03-20 WO PCT/FR2006/000650 patent/WO2006100393A1/fr active Application Filing
  • 2006-03-20 EP EP06743596A patent/EP1869373A1/de not_active Withdrawn

Non-Patent Citations (1)

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