Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0266—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/50—Cooling arrangements
  • F21V29/51—Cooling arrangements using condensation or evaporation of a fluid, e.g. heat pipes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/50—Cooling arrangements
  • F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
  • F21V29/71—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks using a combination of separate elements interconnected by heat-conducting means, e.g. with heat pipes or thermally conductive bars between separate heat-sink elements
  • F21V29/717—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks using a combination of separate elements interconnected by heat-conducting means, e.g. with heat pipes or thermally conductive bars between separate heat-sink elements using split or remote units thermally interconnected, e.g. by thermally conductive bars or heat pipes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0233—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes the conduits having a particular shape, e.g. non-circular cross-section, annular
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2105/00—Planar light sources
  • F21Y2105/10—Planar light sources comprising a two-dimensional array of point-like light-generating elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]

Definitions

• the invention relates to a cooling system for a device comprising electronic and / or electrical components to be cooled, the system comprising an oscillating heat pipe comprising a tube in which a coolant flows in a pulsed manner, the tube being wound so as to form a coil.
• the invention also relates to a device comprising electronic and / or electrical components to be cooled and at least one such cooling system.
• a cooling system including at least one heat pipe of which at least one cold part is in heat exchange with a cold source by convection. They implement a heat exchange means by convection with the cold source, transmitting the heat captured by at least one thermal conduction tube transmitting them laterally to a plurality of cooling radiators in thermal convection with air.
• the cold source unfortunately requires the use of forced convection.
• the flow direction of the heat pipe is important. This results in a difficulty of implementation of mass industrialization.
• the object of the present invention is to provide a cooling system that overcomes the disadvantages listed above.
• an object of the invention is to provide such a cooling system that is inexpensive to produce and assemble, simple, having good performance, and regardless of the relative positions occupied by the hot and cold sources that are in exchange thermal with the cooling system.
• a cooling system for a device comprising electronic and / or electrical components to be cooled
• the system comprising an oscillating heat pipe having a tube in which a coolant circulates from pulsed way, the tube being wound to form a coil, and at least one thermal conduction member in contact with the components and in contact with a main surface of the coil, the thermal conduction member being in contact with a portion of said main surface so that the oscillating heat pipe has at least one hot evaporation portion of the coolant situated at the contact zone between the coil and the heat conduction element and serving to evacuate heat from the components and at least a cold part of condensation of the coolant located outside the contact zone between the coil and the heat conduction element and serving to dissipate the heat absorbed by the oscillatory heat pipe, each cold part of the oscillating heat pipe being in thermal contact by natural or forced convection with air.
• FIGS. 1 and 2 are perspective views of a first example of a cooling system according to the invention
• FIG. 3 is a detailed view of the multiport tube used in FIGS. 1 and 2,
• FIGS. 4 and 5 are perspective views, respectively in the assembled and exploded state, of a second example of a cooling system according to the invention.
• FIGS. 6 to 8 show in perspective three possible embodiments for the arrangement of the cold parts of the oscillating heat pipe
• FIGS. 9 and 10 show a third example of a cooling system according to the invention, respectively in perspective and in view from below,
• FIGS. 11 and 12 represent a fourth example of cooling system according to the invention, respectively in perspective and in view from below,
• FIGS. 13 to 15 show in perspective respectively fifth, sixth and seventh examples of cooling systems according to the invention.
• FIGS. 16 to 20 illustrate five possible embodiments for organizing the coil-wound tube.
• a cooling system 10 for a device that itself comprises electronic and / or electrical components 100 to be cooled comprises an oscillating heat pipe 11 comprising a tube in which a coolant heat transfer fluid for example acetone at 50% of the total internal volume of the tube) flows in a pulsed manner.
• the tube is wound so as to form a coil 12.
• This heat-exchange type 1 1 oscillator is also known by the name of "heat pipe” or under the acronym "PHP" for "pulsating heat pipe” in English terminology.
• the tube is partially filled with heat transfer fluid, in particular of heat-transfer nature, which naturally takes the form of a succession of vapor bubbles and liquid plugs.
• heat transfer fluid in particular of heat-transfer nature, which naturally takes the form of a succession of vapor bubbles and liquid plugs.
• This phase separation results mainly from surface tension forces.
• the oscillating heat pipe 11 is heated in a hot part and cooled in a cold part, the resulting temperature differences generate both temporal and space, themselves associated with the generation and growth of vapor bubbles in the evaporator and their implosion in the condenser. These fluctuations act as a pumping system to transport liquid and vapor bubbles between hot and cold parts.
• the components 100 are chosen in particular from at least one electronic circuit, a thyristor type electronic power component or a bipolar insulated gate transistor, a lighting device comprising light-emitting diodes, a photovoltaic device, a battery, a battery fuel or any other power system.
• the cooling system 10 also comprises at least one heat conduction element 13 in contact with the components 100 and in contact with a main surface 12a of the coil 12.
• the device as such comprises the electronic and / or electrical components 100 to be cooled and at least one such cooling system 10 for cooling these components 100 which are then in contact with the thermal conduction element 13, which last being in contact with the main surface 12a of the coil 12.
• the components 100 include for example an electronic circuit board 101 of the type "MPCB” (for "Metal Printed Circuit Board” in English terminology) equipped with light-emitting diodes 1 02, a collimator device 1 03 and a cover 1 04.
• MPCB Metal Printed Circuit Board
• the heat conduction element 1 3 is preferably constituted by at least one plate or base affixed to the main surface 1 2a of the coil 1 2 and on which the components 1 00 are fixed.
• the plate is fixed to the main surface 1 2a by brazing, welding, bonding, or any equivalent means and adapted to the desired function.
• the circuit 1 01 is fixed to the plate for example by means of fixing screws.
• a thermal interface material thermal grease, thermal conductive polymer or any equivalent solution
• each plate is formed of a material having a thermal conductivity greater than 1 50 W-m "1 - K " 1 .
• the plate is advantageously metallic: it may preferably consist of aluminum or an alloy of aluminum or copper.
• the fourth example according to FIGS. 1 1 and 1 2 and the seventh example according to FIG. 1 correspond to a cooling system 10 in which several plates are in contact with the main surface 1 2a of the coil 1 2, in different zones of it.
• the tube is wound in a main plane so as to form a planar coil 12.
• the tube comprises two opposite main surfaces 12a and 12b, which are outer surfaces of the tube and forming the slice of the heat pipe.
• Each of the two main surfaces 12a and 12b is advantageously flat and oriented in the main plane formed along the X and Y directions. These two surfaces are interconnected by a lateral surface defining the thickness of said tube.
• a lower main surface 12a is defined, part of which is intended to be in contact with the heat conduction element 13 and an upper main surface 12b.
• the thermal conduction element could be in contact with the upper main surface 12b.
• the coil 1 2 thus comprises the upper main surface 12b, which is also flat and oriented in a plane (X, Y).
• the thickness of the coil 12 corresponds to the shift in the Z direction between the main surfaces 12a and 12b.
• the solution described here provides a heat conduction with the hot source to cool, at a main surface of the tube.
• the tube it remains conceivable, however, for the tube to be wound so as to form a coil 1 2 of left shape.
• the plate has significantly greater dimensions in the X and Y directions than in the Z direction. It is for example of parallelepipedal shape. It comprises two opposite faces in the Z direction respectively in mechanical contact with the main surface 1 2a of the coil 1 2 and with the components 100, here the circuit 1 01.
• the zone of the main surface 1 2a of the coil 1 2 in contact with the heat conduction element 1 3 is plane (preferably even in the case of a coil of left form) and parallel at least one plane in which the heat transfer fluid circulates inside the tube.
• the tube may advantageously be constituted by an extruded multiport tube delimiting channels 14 ( Figure 3) parallel to each other, in each of which pulsed circulation of a fraction of the total amount of coolant circulating in the tube.
• the winding of the tube is carried out so that each channel 14 extends in a plane (X, Y) so that the fraction of heat transfer fluid circulating there flows in a plane (X, Y).
• These flow planes are all parallel and offset in pairs, in particular in the direction Z.
• the zone of the main surface 12a of the coil 12 in contact with the heat conduction element 13 is parallel to these planes in which the coolant fractions circulate separately.
• the extruded tube multiport is organized in particular so that the channels 14 are all shifted in pairs in the same direction, especially in the direction Z.
• the tube then has the general shape a ribbon and the channels 14 are distributed along the width of this ribbon.
• the width of this ribbon is directed in the direction Z.
• the ribbon is wound in the aforementioned main plane to form the coil 12. All the channels 14 are parallel and stacked in the direction Z.
• each channel 14 may be independent of one another and may not communicate with one another fluidically with respect to the coolant.
• Figure 16 corresponds to an embodiment in which each channel 14 has the form of an open loop.
• each channel 14 constitutes an individual oscillatory heat pipe forming an open loop.
• the embodiment according to Figure 17 provides that each channel 14 has the form of a closed loop.
• each channel 14 constitutes an individual oscillatory heat pipe forming a closed loop.
• FIGS. 18 to 20 With reference to FIGS. 18 to 20, several of the channels 14, or even all the channels 14 delimited by the multiport tube, are interconnected with one another, in particular at their ends, so as to form a coil-shaped conduit wound in one direction. perpendicular to the main surface 12a, that is to say in the direction Z in the illustrated example.
• FIG. 18 corresponds to an embodiment in which this duct has the form of an open loop while the embodiment according to FIG. 19 provides that this duct has the shape of a closed loop.
• Figure 20 provides that at both ends of the multiport tube, all channels 14 are interconnected by a common collector 16 to all channels. It is possible to provide that only one end of the multiport tube is equipped with such a collector 16.
• the common collector 16 is intended to allow a parallel connection of all the channels.
• the selection and implementation of an embodiment chosen from those of FIGS. 16 to 20 depend on the design of end plugs intended to be butted at the ends of the tube so as to arrange the channels 14 of the desired manner according to the selected embodiment.
• the coil 12 is of advantageously flat shape for reasons of ease of winding and bulk, it is preferably shaped so as to be among one of the following types: with parallel turns, with spirals in a square spiral, with turns circular spiral.
• the third example according to FIGS. 9 and 10 corresponds to a cooling system 10 in which the coil 12 is shaped so as to present spirals in a square spiral.
• An advantage of this configuration is the fact of being able to provide a spacing between the turns having a lower value than in the configuration with parallel turns. This makes it possible to avoid too small radii of curvature on the multiport tube, which adversely affects the performance of the oscillating heat pipe 1 1.
• the spacing between the turns being smaller, it is possible to obtain a more compact assembly because more surface is developed for convection with air.
• There is a minimum value of the spacing between the turns known to those skilled in the art, below which it is however necessary not to go down so as not to slow down the natural convection.
• the volume in the center of the spiral can be used to house the control electronics of the diodes 102.
• the fourth example according to FIGS. 11 and 12 corresponds to a cooling system 10 in which the coil 12 is shaped so as to have circular spiral turns. It has the same advantages as the example with spiral spirals. Moreover, the radius of curvature of the multiport tube being further increased, the performance is improved compared to the example with spiral spirals square.
• the organization of the turns within the coil 12 can however be any such that the illustrated examples are in no way limiting the scope of the solution.
• the heat conduction element 13 is constituted in particular by one or more plates.
• the thermal conduction element 13 is in contact via said at least one plate on a part only of the main surface 12a so that the oscillating heat pipe 1 1 has:
• the oscillating heat pipe 1 1 comprises a hot part at each platen in contact with the main surface 12.
• the hot part corresponds, at each platen, to the serpentine surface 12 delimited in the plane (X, Y ) by the contour of the contact surface between said plate and the main surface 12a.
• Each cold part is formed on the other hand outside the contact areas between the (the) plate (s) and the main surface 12a.
• the heat pipe 1 1 may comprise one or more cold parts.
• the first example according to FIGS. 1 to 3, the second example according to FIGS. 4 and 5, the third example according to FIGS. 9 and 10 and the sixth example according to FIG. 14 each correspond to a cooling system 10 in which the oscillating heat pipe 1 1 comprises a single hot portion (at the contact surface between the single plate and the main surface 12a) located in a central zone of the coil 12 in the X direction and two cold parts located in the lateral zones of the coil 12 shifted together in the direction X and arranged on either side of the hot part in this direction X.
• Each hot and cold part extends over the entire width of the heat pipe oscillating 1 1 in the lateral direction Y.
• the hot part is disposed only on a part of the heat pipe width in the lateral direction Y.
• the heat pipe oscillating 1 1 forms loops which are naturally convected in the air so as to constitute the two cold parts.
• the fourth example according to FIGS. 11 and 12 corresponds to a cooling system 10 in which the oscillating heat pipe 11 comprises four hot parts (at the level of the contact surface between the four plates and the main surface 12a) angularly distributed in the plane (X, Y) around the circular spiral and four cold parts delimited two by two by the hot parts. It goes without saying that the number of plates may be different from four.
• the fifth example according to FIG. 13 corresponds to a cooling system 10 in which the oscillatory heat pipe 11 comprises a single hot part (at the level of the contact surface between the single plate and the main surface 12a) located in a lateral zone. of the coil 12 in the direction X and only one cold part located in the other lateral zone of the coil 12 in the direction X.
• Each hot and cold part extends over the entire width of the heat pipe oscillating January 1 in the lateral direction Y.
• the hot part is disposed only over a portion of the width of the heat pipe oscillating January 1 in the lateral direction Y.
• the seventh example according to FIG. 15 corresponds to a cooling system 10 in which the oscillatory heat pipe 11 comprises three hot parts (at the level of the contact surface between the three plates constituting the heat conduction element 13 and the main surface 12a).
• the three hot parts extend over the entire width of the heat pipe oscillating January 1 in the lateral direction Y.
• the three plates are spaced apart from each other in the direction X so as to delimit two cold parts.
• the two plates are spaced from the lateral edges of the coil 12 so as to delimit two additional cold parts.
• the oscillating heat pipe 11 comprises an alternation of four cold parts and three hot parts. It goes without saying that the number of plates may be different from three.
• each cold part of the oscillating heat pipe 11 is in thermal contact by natural or forced convection with air. It is in this way that the heat pipe 1 1 1 dissipates the heat previously captured from the components 100.
• the cooling system 10 may include a device for moving air, such as a fan not shown.
• the system 10 may optionally comprise heat exchange fins 15 arranged between the turns of the coil 12 so as to connect them in pairs.
• heat exchange fins 15 may be arranged at least at the level of said at least one cold part, or possibly at the level of said at least one hot part. They are for example formed of aluminum.
• FIG. 6 represents the case where such heat exchange fins 15 are absent between the turns of the coil 12.
• heat exchange fins 15 attached to the outer walls of the tube between two adjacent turns, allow to increase the exchange surface in natural or forced convection of each cold part provided with such fins. They can be accordion and fixed between the turns of the coil 12 in the manner shown in Figures 7 and 8. They can be rectangular, triangular or any other known and adapted form.
• the heat exchange fins 15 may be corrugated, perforated, offset, louvers .... More generally, they may have any other means for improving the heat exchange coefficient with the air to increase heat transfer in natural or forced convection.
• the use of fins 15 increases the compactness of the cooling system by increasing the exchange surface with air.
• the solution described above has the advantage of being inexpensive to produce and assemble, to be simple while having good performance, and regardless of the relative positions occupied by the hot and cold sources that are in heat exchange with the 10.
• the cooling system 10 described above has good performance irrespective of the spatial orientation of the oscillatory heat pipe 11 (to which the reference (X, Y, Z) is bound) in an absolute reference.
• the cooling performance is very good even in the case illustrated in Figures 2 and 4 where the components 100 to cool, constituting the heat source in thermal coupling with the hot part of the pulsed heat pipe, is arranged spatially in an absolute benchmark above the cold parts of the pulsed heat pipe that are in thermal coupling with the air by natural or forced convection.
• this solution has at least the advantage of reducing the thermal resistance in the hot and cold parts, not requiring complex assembly and being simple to implement and to achieve, to present very good thermal performance and to benefit from a high exchange surface between the channels of the coil and the air by natural or forced convection, to require little material and to be inexpensive.
• Each component supplied with a current of 700 mA dissipates a thermal power of 1.5 W for a luminous flux of about 220 lumens.
• the thermal power to be dissipated is 37.5 W for a light output of 5500 lumens.
• heat transfer fluid acetone, methanol, ammonia, n-heptane, tetrafluoroethane, fluorocarbons,
• thickness of the fins 15 between 0.1 and 0.3 mm
• space between the fins 15 between 1 and 15 mm.
• the plate has a dimension of 40 to 90 mm along the X and Y axes (width and length) and from 2 to 10 mm along the Z axis (thickness).
• the length of each cold part of the tube is between 20 and 200 mm and the width of each cold part of the tube is between 40 and 200 mm.
• the implementation of the device can provide the following steps:
• the tube may comprise only one channel, preferably wound plane in the X, Y plane disposed on the side of the thermal conduction element.
• the tube is optionally stiffened by a stiffening core, in particular a solid core directed along Z on the side opposite to the thermal conduction element with respect to the single channel.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

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Citations (6)

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• 2013
  • 2013-06-18 FR FR1355744A patent/FR3007122B1/fr active Active
• 2014
  • 2014-06-13 EP EP14729900.2A patent/EP3011249B1/de active Active
  • 2014-06-13 WO PCT/EP2014/062334 patent/WO2014202474A1/fr active Application Filing

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