heat exchanger device

Abstract

Heat exchanger device (0) comprising: - a block (1) having a density greater than 2 g / cm³ and having a thermal conductivity at 20°C between 0.8 Wm−1.K−1 and 5 Wm−1.K−1, characterized in that the heat exchanger device (0) comprises at least one heat exchange element (2) having a first portion disposed outside the block (1) and at least a second portion embedded in the block (1), said at least one heat exchange element (2) having a thermal conductivity at 20°C that is greater than four times said thermal conductivity at 20°C of the block (1). FIGURE IN ABRIDGED DIAGRAM: Fig. 1

Description

Title of the invention: Heat exchanger device.

[0001] BACKGROUND OF THE INVENTION

[0002] The present invention relates to the field of heat exchanger devices having thermal inertia.

[0003] A heat exchanger device is known comprising a block having a density greater than 2g / cm3, which allows a high thermal inertia of the block, and having a thermal conductivity at 20°C between 0.8 Wm-lK-1 and 5 Wm-lK-1.

[0004] Such a block has:

[0005] - good thermal inertia which allows heat to be stored in the block; and

[0006] - a limited thermal conductivity which allows, over a period of time the diffusion of stored heat is very slow.

[0007] Heat diffusion takes place over a period ranging from ten minutes to several hours, depending on the amount of heat stored, the size of the block and the conditions of thermal diffusion around the block.

[0008] Such a block of prior art is, for example, a block of natural stone.

[0009] This heat exchanger device can be heated intermittently and the accumulated heat is then diffused over time.

[0010] The choice of the material constituting the block and the shape of the block determine the heat storage capacity in the block, the kinetics of heat diffusion by the heat exchanger device and the spatial distribution of the heat thus diffused.

[0011] It would be useful to modify the heat diffusion kinetics and the spatial distribution of the diffused heat while limiting the impact of these modifications on the heat storage capacity of the device.

[0012] SUBJECT OF THE INVENTION

[0013] The invention aims in particular to provide a heat exchanger device that is simple to manufacture and that makes it possible to mitigate all or part of the disadvantages of the aforementioned prior art. Summary of the invention

[0014] For this purpose, according to the invention, a heat exchanger device is provided comprising a block having a density greater than 2g / cm3 and having a thermal conductivity at 20°C between 0.8 W.mAK1 and 5 Wm-'.K-1.

[0015] The heat exchanger device according to the invention is essentially characterized in that it comprises at least one heat exchanger part having a first portion disposed outside the block and at least a second portion embedded in the block, said at least one heat exchanger part having a thermal conductivity at 20°C, which is greater than four times said thermal conductivity at 20°C of the block.

[0016] With a density greater than 2g / cm3, the block exhibits good thermal inertia and consequently a good heat storage capacity, this capacity varying according to the dimensions of the block (total mass, thickness, height, width).

[0017] Furthermore, the thermal conductivity of the block is low compared to the thermal conductivity of said at least one heat exchange part, which allows for heat diffusion to the outside of the device, which is essentially achieved via the heat exchange part.

[0018] This heat exchange part must therefore be specifically defined / dimensioned according to the expected thermal diffusion characteristics for the heat exchanger device without affecting the heat storage capacity of the block.

[0019] The constituent material of the block is, by mass, essentially made up of one or more solid, mineral and non-metallic materials, that is to say a constituent material which is neither a thermal insulator (a thermal insulator having a thermal conductivity at 20°C less than 0.065 Wm K *), nor a metal, nor an alloy of metals (a metal or an alloy of metals has a thermal conductivity at 20°C between 20 and 418 Wm K-1).

[0020] As stated, at least one heat exchange component has a first portion located outside the block and a second portion embedded in the block, resulting in: - a first heat exchange by conduction, within the block, between the block and said at least one heat exchange component; and - a second heat exchange, by convection and / or radiation, outside the block, between said at least one heat exchange part and the environment in which the first portion of said at least one heat exchange part is located.

[0021] Typically, if the medium in which the first portion of said at least one heat exchange part is located is air, or a liquid, the second heat exchange outside the block is essentially an exchange by convection (with a movement of air or liquid) and by radiation.

[0022] The connection by embedding of said at least a second portion of said at least heat exchange part in the block allows to obtain a very good heat exchange by conduction between the block and said at least one heat exchange part.

[0023] Since the heat exchanger has a high thermal conductivity compared to the thermal conductivity of the block, heat is diffused from the block to the environment of the device via the heat exchanger, the block essentially serving as a heat storage reservoir and the heat exchanger of diffuser.

[0024] In summary, the heat exchanger device according to the invention is a composite device (made up of several materials assembled together) which allows the accumulation of heat in the block and the progressive diffusion of this heat via the heat exchange piece which is partly embedded in the block.

[0025] Energy storage in the block can be achieved over a reduced time range, with a strong thermal input to the block while thermal diffusion can be spread over a wider time range.

[0026] Moreover, the heat exchanger device is economical and simple to manufacture, since the connection by embedding of the heat exchange part with the block is easily achieved by overmolding or possibly by gluing (the latter method not being preferred because it complicates the assembly and can affect thermal conduction).

[0027] The block / heat exchange part assembly can be achieved by molding: - either by bringing the constituent material of the block in liquid form, into a mold in which the block can harden and solidify around each second portion of the heat exchange part; - either by bringing the said constituent material to at least one heat exchange part, in liquid form, into a mold in which the heat exchange part can harden and solidify, each second portion of the heat exchange part then solidifying in a corresponding recess formed in the block.

[0028] Thus each heat exchange part is simply embedded in the block, without requiring any additional assembly parts or means of assembly such as nails, screws, pins, glue or welding.

[0029] The mechanical link between the block and the heat exchange part is mechanically resistant and efficient in terms of thermal conduction.

[0030] The heat exchanger device according to the invention is advantageously usable for transmitting heat generated by a discontinuous heat source, this heat being first accumulated in the block and then progressively diffused by conduction towards each at least one heat exchange piece, and then progressively diffused towards the outside of the heat exchanger device via the first portions of each of the heat exchange pieces.

[0031] Other features and advantages of the invention will become apparent from the following description of particular, non-limiting embodiments of the invention. Brief description of the drawings

[0032] Reference will be made to the attached drawings, among which:

[0033] [Fig.1] Fig.1 illustrates a cross-sectional view of a heat exchanger device 0 according to a first embodiment of the invention in which the device 0 comprises several heat exchange parts 2, 2a, 2b, 2c distinct from each other and each having a second portion embedded in the block 1 and a first portion outside the block;

[0034] [Fig.2] [Fig.2] illustrates a cross-sectional view of a heat exchanger device 0 according to a second embodiment of the invention, the device 0 comprising a single heat exchange piece 2 having a plurality of second portions each embedded in the block 1, the heat exchange piece defining with a face of the block 1 several parallel air passage channels 3, 3a, each of these channels being open at its terminal ends and being closed at the periphery when observed in a cross-section plane (this promoting air circulation by convection in each channel);

[0035] [Fig.3] [Fig.3] illustrates a cross-sectional view of a heat exchanger device 0 according to a third embodiment of the invention, the device 0 still comprising a single heat exchange piece 2 having a plurality of second portions each embedded in the block 1, the heat exchange piece 2 comprising tubes 21, 21a, 21b, 21c parallel to each other and located outside the block 1, each given tube forming an air passage to allow air circulation through the given tube and consequently through the heat exchange piece 2 (each tube increasing the heat exchange surface with the air surrounding the heat exchange piece 2). DETAILED DESCRIPTION OF THE INVENTION

[0036] As previously stated and in accordance with each of the embodiments illustrated in Figures 1, 2, 3, the invention relates to a heat exchanger device 0 comprising:

[0037] - a block 1 having a density greater than 2g / cm3 (which allows a strong thermal inertia of the block) and having a thermal conductivity at 20°C between 0.8 W.m'.K1 and 5 W.m'.K1; and

[0038] - at least one heat exchanger 2 having a first portion arranged at the exterior of block 1 and at least a second portion embedded in block 1.

[0039] Said at least one heat exchanger piece 2 has a thermal conductivity at 20°C which is greater than four times said thermal conductivity at 20°C of block 1.

[0040] The heat exchanger device 0 according to any one of the embodiments of the invention has the particularity of having a block 1 in a first material and at least one heat exchange part 2 in a second material distinct from the first material.

[0041] Each at least one heat exchange part 2 is mechanically linked to the block 1 via a fixed connection which promotes thermal conduction to each heat exchange part.

[0042] In other words, each heat exchange part 2 has a second portion which is its own and which is embedded in the block 1 and a first portion which is its own and which is outside the block 1 to carry out a heat exchange with the ambient environment surrounding the heat exchanger device 0.

[0043] As previously stated, the block has significant thermal inertia.

[0044] Each heat exchanger 2, for its part, has a thermal conductivity at least four times greater than the thermal conductivity of the block, which allows it to diffuse heat from the block to an area external to the block via the first portion of the heat exchanger. This provides guidance of the heat flow towards a dedicated area outside the block.

[0045] The fixed connection between the block and the heat exchange part is simple, economical to manufacture, efficient in terms of thermal conduction, mechanically resistant and durable.

[0046] Preferably, the block represents a total volume which is at least 5 times greater than the total volume of all the first portions of the heat exchange parts (the first portion of a given heat exchange part is the portion of that part located outside of block 1).

[0047] The total volume of the block is the total volume of material constituting the block.

[0048] Similarly, the total volume of all the first portions of the heat exchange parts corresponds to the total volume of material constituting these first portions of the heat exchange parts.

[0049] This results in a heat storage capacity at the block level which is significantly greater than the heat diffusion capacity via the heat exchange parts.

[0050] This allows for efficient heat transfer into the ambient environment over a period of time that can extend over several hours, while the heat source for heating the block is discontinuous.

[0051] In addition, the block and each heat exchange part allows heat to be diffused by radiation.

[0052] Preferably, each at least one heat exchange part 2 has a thermal conductivity at 20°C between 20 and 418 W.nr1. K-1.

[0053] This thermal conductivity value at 20°C, between 20 and 418 Wm K 1, corresponds to the thermal conductivity values ​​specific to metals or metal alloys, which implies that each heat exchange part is mainly made of metals.

[0054] Each heat exchanger part 2 metallic and here formed of a metallic alloy such as an aluminium alloy.

[0055] Preferably, block 1 is predominantly made up by mass of at least one of the materials from the group of materials comprising concrete, fiber-reinforced concrete, ultra-high-performance fiber-reinforced concrete, rock, slate, basalt, limestone, chalk, granite, sandstone, marble, lime mortar, shale, ceramic, glass, porcelain, natural stone, plaster, or any mixture of these materials.

[0056] These materials exhibit good mechanical resistance while being widely available and affordable.

[0057] In the present case, block 1 is made of ultra-high-performance fiber-reinforced concrete.

[0058] By definition, ultra-high-performance fiber-reinforced concrete, also called UHPC, is a cementitious matrix material, reinforced with fibers and offering a compressive strength greater than 100 MPa, usually between 100 MPa and 400 MPa.

[0059] The advantage of using ultra-high-performance fiber-reinforced concrete as the constituent material of block 1 is that the block 1 is then very mechanically resistant while having high thermal inertia (without having to use internal reinforcement) and while being easy to shape / implement by molding. These fibers are preferably made of an electrically insulating material, such as polymer(s) and / or mineral and / or plant fibers (plant fibers are only usable in applications where the maximum heating temperature of the block does not exceed 80°C).

[0060] Another advantage of having an ultra-high-performance fiber-reinforced concrete block is that it can be used directly as a heat exchanger facade because this material allows a variety of finishes (choice of smooth, satin, glossy finishes, possibility of adding colors / pigments or playing with textures).

[0061] In addition, UHPC makes it possible to obtain a thin block that is particularly strong and has durable mechanical performance favorable to a strong mechanical bond between the block and each heat exchange part.

[0062] Furthermore, UHPC has a very good heat exchange capacity by conduction to the heat exchange part(s) which is / are embedded in the block.

[0063] Preferably, block 1 is made of a material or a mixture of materials that is molded. This material or mixture of materials is preferably designed to be moldable and hardenable over a temperature range from -20°C to +50°C.

[0064] In addition to simplifying the production of the block and providing freedom in choosing its dimensions, molding the block improves heat exchange between the block and the heat exchange parts.

[0065] In this embodiment, the block is preferably molded around and against each at least a second portion of heat exchange part 2 so as to obtain an embedding of each at least a second portion in block 1.

[0066] With reference to the embodiment of [Fig. 1], the heat exchanger device comprises a plurality of heat exchange parts 2, 2a, 2b, 2c, said at least one heat exchange part 2 belonging to said plurality of heat exchange parts.

[0067] Each of the heat exchange parts 2, 2a, 2b, 2c of the plurality has a first portion which is its own and which is disposed outside the block 1 and at least a second portion which is its own and which is embedded in the block 1.

[0068] The heat exchange parts of the plurality of heat exchange parts have the same thermal conductivity at 20°C (these parts 2, 2a, 2b, 2c are here made of the same material).

[0069] This embodiment can be advantageous because it allows the block 1 to expand freely without differential expansion constraints between the different parts 2, 2a, 2b, 2c, which are fixed in the block independently of each other.

[0070] In the embodiment of [Fig.1], the heat exchange parts 2, 2a, 2b, 2c of the plurality of heat exchange parts are arranged at a distance from each other to delimit air passage channels 3, 3a, 3b between these parts 2, 2a, 2b, 2c.

[0071] Each air passage channel 3, 3a, 3b is: - on one side delimited by a heat exchange surface belonging to one of the heat exchange components 2, 2a, 2b, 2c of said plurality; and - on the other hand delimited by a heat exchange surface belonging to another of the heat exchange parts 2, 2a, 2b, 2c of said plurality of parts.

[0072] Each of these air passage channels 3, 3a, 3b has a side which is delimited by a portion of an external face Fl of the block 1 opposite which extend the first portions of the heat exchange parts 2, 2a, 2b, 2c of the plurality of parts.

[0073] Thus, the air circulating in a given channel receives heat from the block either directly via the face Fl of the block, or indirectly via the first portions of the heat exchange parts 2, 2a, 2b, 2c, which is an efficient and economical way of obtaining a large heat exchange surface.

[0074] Typically, as illustrated in the embodiment of [Fig.1], the heat exchange parts each form a straight fin extending along a longitudinal direction which is preferably vertical to promote natural convection.

[0075] According to the embodiments illustrated in Figures 2 and 3, the heat exchanger device 0 according to the invention comprises a single heat exchanger part 2 which includes several fins 2x, 2y, 2z spaced apart to delimit air passage channels 3, 3a, 3b, 3c, these fins possibly being parallel to each other.

[0076] Each air passage channel 3, 3a, 3b, 3c is delimited on one side by a heat exchange surface belonging to one of the fins 2x, 2y, 2z of the heat exchange part 2 and is delimited on the other side by a heat exchange surface belonging to another of the fins 2x, 2y, 2z of the heat exchange part 2.

[0077] These fins 2x, 2y, 2z of said heat exchange part 2 are connected to each other by a connecting portion 2n which belongs to said at least one heat exchange part 2.

[0078] More particularly, the connecting portion 2n belongs to the first portion of the connecting piece which is arranged outside the block 1.

[0079] This embodiment is advantageous because the connecting portion 2n allows the heat exchange surface between the heat exchange part 2 and the ambient environment in which the first portion of the heat exchange part is located to be increased.

[0080] The connecting portion 2n is located at a distance from the block 1 so as to define the plurality of air passage channels 3, 3a, 3b, 3c, each air passage channel 3, 3a, 3b, 3c being disposed between a face Fl of the block 1 and said connecting portion 2n while being, on one side delimited by a face of one of the fins 2x, 2y, 2z of said at least one heat exchange part 2, and on the other side delimited by a face of another of the fins 2x, 2y, 2z of said at least one heat exchange part 2.

[0081] In this way, each channel 3, 3a, 3b, 3c is closed at its periphery to guide the passage of air in the channel and along the channel, between the heat exchange piece 2 and the face Fl of the block 1.

[0082] With this embodiment, the heat exchange surface area is simply increased by ensuring that the connecting portion 2n is positioned at a distance from the block. This is particularly easy to implement without increasing the manufacturing cost of the heat exchanger device 0.

[0083] In any one of the embodiments of the invention illustrated in figures 1 to 3, it is preferably arranged that each heat exchange part 2, 2a, 2b, 2c has a heat exchange surface in contact with the block (in the block) and a heat exchange surface disposed outside the block.

[0084] Each heat exchange piece 2, 2a, 2b, 2c is shaped so that its heat exchange surface in contact with the block represents between 5% and 25% of its heat exchange surface located outside the block.

[0085] This feature ensures a good mechanical connection between each heat exchanger part and the block while ensuring good heat diffusion from the block to the external environment of device 0 via the heat exchange part(s) 2.

[0086] For a given heat exchange part, its heat exchange surface in contact with block 1 is the sum of all its surfaces in contact with the block and located on the block.

[0087] Similarly, said heat exchange surface of the heat exchange part 2 disposed outside the block 1 is the sum of all the surfaces of the heat exchange part which are in contact with the ambient air in which the device 0 according to the invention is located.

[0088] In the embodiment of the heat exchanger device 0 illustrated in [Fig.3], said at least one heat exchanger part 2 comprises tubes 21, 21a, 21b, 21c which are parallel to each other and which are located outside the block 1.

[0089] Each given tube 21, 21a, 21b, 21c forms an air passage to allow air to circulate through the given tube, between open longitudinal ends of the given tube.

[0090] Thus, each air passage formed through one of the tubes 21, 21a, 21b, 21c of the heat exchange part 2 passes through an opening formed at one end of the tube and through another opening formed at a second end of the tube.

[0091] Ideally, the first end of the tube is a low opening while the second end of the tube is a high opening so that each tube extends vertically.

[0092] This embodiment promotes heat exchange by convection, inside and outside each tube.

[0093] The tubes preferentially have the same shape when observed in cross-sectional plane, in this case they have an octagonal shape but they could also have a circular shape.

[0094] Typically, and in any one of the embodiments of the invention, each heat exchange piece is made to be a profile extending along a longitudinal direction (here the longitudinal direction is vertical), the profile having a constant cross-section in any plane of section perpendicular to said longitudinal direction of the profile.

[0095] This makes it easier to manufacture the heat exchange parts which can be obtained by cutting to the desired length a profile obtained by extrusion in a die.

[0096] The dimensions of the heat exchange parts are thus defined by the shape of the die and by the cutting operation of the extruded profile.

[0097] The manufacturing cost of the heat exchange parts is thus minimized without compromising the quality of these parts.

[0098] In the embodiment of [Fig. 3], the heat exchange part 2 defined with a face Fl of block 1 several air passage channels 3, 3a, 3b, 3c which are parallel to each other.

[0099] Each of these channels 3, 3a, 3b, 3c is open at its terminal / longitudinal ends and is closed peripherally when viewed in a cross-section plane of the channel.

[0100] Each of these channels 3, 3a, 3b, 3c promotes air circulation by convection in the channel, between part 2 and block 1.

[0101] Preferably, in any of the embodiments of the device 0 according to the invention, the block 1 can be in the form of a plate, preferably in the form of a rectangular parallelepiped plate.

[0102] In this embodiment, each first portion of heat exchange part 2 extends opposite the same main face Fl of the plate-shaped block.

[0103] Preferably, in any of the embodiments of the device 0, it may also include supports SI, S2 mechanically connected to block 1 (here the connection is a fixed-type connection).

[0104] These supports SI, S2 are arranged so as to present a flat part suitable for bearing against a wall M against which these supports SI, S2 can be fixed by means of screws.

[0105] These supports carry the block 1 and the heat exchange part(s) 2 while keeping the main face Fl of the block 1 parallel to the wall M.

[0106] Wall M is here symbolized by dotted lines.

[0107] Preferably, in any of the embodiments of the heat exchanger device 0 according to the invention, the device 0 may include at least one first electric heating resistance R in contact with the block 1 to transfer heat from the electric heating resistance R to the block 1.

[0108] Thus, the heat exchanger device is here an electric radiator allowing the heating of air in a room, this device being able to be carried by a support of the type of casters or preferably via supports SI, S2 arranged to be fixed on a wall M, as indicated previously.

[0109] Said at least a first electrical heating resistance R is preferably made of a material which contains graphene or graphene oxide or a mixture of graphene and graphene oxide.

[0110] The constituent material of the first electrical heating resistance may also contain ultra-high performance fiber-reinforced concrete (UHPFRC) and graphene or graphene oxide or a mixture of graphene and graphene oxide.

[0111] This resistance material combining UHPC and graphene or graphene oxide or a mixture of graphene and graphene oxide thus exhibits significant mechanical resistance.

[0112] Furthermore, in embodiments where the block 1 in contact with the resistance also contains ultra-high performance fiber-reinforced concrete, the durability of the mechanical bond between the block and the heating resistance is improved because the ultra-high performance fiber-reinforced concrete of the block and that containing graphene and / or graphene oxide of the electrical resistance have similar mechanical characteristics (the fibers acting as reinforcements minimizing the risks of cracking of the materials).

[0113] The block carries at least one heating resistance R.

[0114] In this embodiment, the heat exchanger device 0 comprises at least first and second electrodes 4a, 4b electrically connected to each other via said at least one first heating resistance R.

[0115] The block which has very good thermal inertia allows on the one hand an accumulation of the heat produced by the first heating resistance R and on the other hand a diffusion of heat long after the electrical supply to the resistance R has been stopped.

[0116] Thus, the heat exchanger device makes it possible to dampen a discontinuous supply of heat from the resistance R.

[0117] The first electrical heating resistance R can be achieved by applying against the block, a crosslinkable liquid mixture containing graphene or graphene oxide or a mixture of graphene and graphene oxide.

[0118] Alternatively, block 1 can be made by molding the block against the first electrical heating resistance R.

[0119] The electrodes 4a, 4b can be arranged between the first electrical heating resistance R and the block 1.

[0120] Alternatively, the electrodes 4a, 4b can be arranged against a face of the first electrical heating resistance R which is oriented opposite to block 1, i.e. which is oriented towards the outside of the heat exchanger device.

[0121] This allows the operations of fixing the resistance R against the block 1 to be separated from the operations of fixing the electrodes 4a, 4b against the heating resistance R.

[0122] In a particular embodiment of the heat exchange device 0 according to the invention, as a replacement or in addition to said heating resistance R, the device 0 could include one or more conduits for transporting a heat transfer fluid.

[0123] Each heat transfer fluid transport duct is in contact with block 1 to transfer heat from the heat transfer fluid circulating in the duct to block 1.

[0124] Such heat transfer fluid transport ducts can be arranged outside of block 1 or be at least partially embedded inside the block, this block being preferably molded against and / or around these heat transfer fluid transport conduits.

Claims

Claims

1. Heat exchange device (0) comprising: - a block (1) having a density greater than 2g / cm3 and having a thermal conductivity at 20°C of between 0.8 W.nr'.K-1 and 5 Wm '.K 1; and - at least one heat exchange part (2) having a thermal conductivity at 20°C which is greater than four times said thermal conductivity at 20°C of the block (1), characterized in that said at least one heat exchange part (2) comprises a first portion arranged outside the block (1) and at least one second portion embedded in the block (1), the block (1) being made of ultra-high performance fiber-reinforced concrete and being molded around and against each at least one second portion of heat exchange part (2) so as to obtain an embedding of each at least one second portion in the block (1).

2. Heat exchange device (0) according to claim 1, wherein said at least one heat exchange part (2) has a thermal conductivity at 20°C of between 20 and 418 W.nr1. K-1.

3. Heat exchange device (0) according to any one of claims 1 or 2, wherein said at least one heat exchange part (2) is metallic.

4. A heat exchange device (0) according to any one of claims 1 to 3, comprising a plurality of heat exchange parts (2, 2a, 2b, 2c), said at least one heat exchange part (2) belonging to said plurality of heat exchange parts, each of the heat exchange parts (2, 2a, 2b, 2c) of the plurality having a first portion arranged outside the block and at least one second portion embedded in the block (1), and said heat exchange parts (2, 2a, 2b, 2c) of the plurality of heat exchange parts having the same thermal conductivity at 20°C.

5. Heat exchange device (0) according to claim 4, wherein the heat exchange parts of the plurality of heat exchange parts are arranged at a distance from each other to delimit air passage channels (3, 3a, 3b, 3c), each air passage channel being on one side delimited by a heat exchange surface belonging to one of the heat exchange parts (2, 2a, 2b, 2c) of said plurality and being on the other side delimited by a surface heat exchanger belonging to another of the heat exchange parts (2, 2a, 2b, 2c) of said plurality.

6. Heat exchange device (0) according to any one of claims 1 to 5, wherein said at least one heat exchange part (2) comprises several fins (2x, 2y, 2z) spaced from each other to delimit a plurality of air passage channels (3, 3a, 3b, 3c), these fins (2x, 2y, 2z) being connected to each other by a connecting portion (2n) belonging to said at least one heat exchange part (2).

7. Heat exchanger device (0) according to claim 6, wherein the connecting portion (2n) is located at a distance from the block so as to define the plurality of air passage channels (3, 3a, 3b, 3c) between a face (Fl) of the block (1) and said connecting portion (2n) while being, on one side delimited by a face of one of the fins (2x, 2y, 2z) of said at least one heat exchange part (2), and on another side delimited by a face of another of the fins (2x, 2y, 2z) of said at least one heat exchange part (2).

8. Heat exchange device (0) according to any one of claims 1 to 7, in which each heat exchange part (2) comprises a heat exchange surface in contact with the block (1) and a heat exchange surface arranged outside the block (2), each heat exchange part (2) being shaped so that its heat exchange surface in contact with the block (1) represents between 5% and 25% of its heat exchange surface arranged outside the block (1).

9. Heat exchange device (0) according to any one of claims 1 to 8, wherein said at least one heat exchange part comprises tubes (21, 21a, 21b, 21c) parallel to each other and located outside the block (1), each given tube (21, 21a, 21b, 21c) forming an air passage to allow air circulation through the given tube, between open longitudinal ends of the given tube.

10. Heat exchanger device (0) according to any one of claims 1 to 9, comprising at least one first electrical heating resistor (R) in contact against the block (1) to transfer heat from the electrical heating resistor (R) to the block (1).

11. Heat exchanger device according to claim 10, wherein said at least one first electrical heating resistor (R) is in a material which contains graphene or graphene oxide or a mixture of graphene and graphene oxide, said block (1) carrying this at least one heating resistor (R) and the heat exchanger device (0) comprising at least first and second electrodes (4a, 4b) electrically connected to each other via said at least one first heating resistor (R).

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