EP0393107B1 - Heat-exchanger - Google Patents

Abstract

The invention concerns a heat-enchanger comprising at least one cross-flow heat-exchanger module (M) having two alternately attached sets of plates (1a, 1b). Each plate (1a, 1b) has internal channels (5a, 5b) for gas circulation which extend longidutinally, parallel and unidirectionally inside the plate (1a, 1b). The channels (5a, 5b) in one set of plates (1a, 1b) are aligned in the same direction and at a predetermined angle to the direction of alignment of the channels (5a, 5b) in the other set of plates (1a, 1b). According to the invention, a certain number of plates (1a, 1b) of said module have at least one opening (E), obtained in particular by cutting, which facilitates heat exchange between the gas streams. The invention is useful in ventilation or air-conditioning installations in enclosed spaces such as offices, cinemas, theatres, conference rooms, indoor stadia, private homes, apartment blocks, factories, etc.

Description

The present invention relates to an energy recuperator, in particular finding application in ventilation or air conditioning installations of loudspeakers, such as for example offices, cinema, theater and conference halls, sports halls, individual houses or collectives, factories, etc., the internal temperature of which is different from the external temperature according to the preamble of claim 1. Such a recuperator is known according to FR-A-2 469 684.

It is known that in ventilation or air conditioning systems, stale air heated or cooled is extracted by a fan through a network of ducts, while fresh air respectively cold or hot is injected, whence results in a loss of calories.

Many energy recuperators have therefore been designed, in particular to reduce the energy losses resulting from the use of such ventilation or air conditioning systems. The basic idea is to recover part of the lost calories transported by the air leaving the enclosure, to transfer it to the air entering the enclosure.

Such known recuperators generally comprise one or more energy exchanger modules, capable of being crossed by two gas streams circulating in a crossed manner, and intended for the transfer of part of the calories from one of said gas streams to the other. .

Many designs have been envisaged for the production of these exchangers, the problem consisting in searching for materials, and a configuration guaranteeing an optimal yield (quantity of energy recovered and transferred), and satisfactory overall mechanical strength.

The solution adopted for the production of these energy exchanger modules consists of the assembly of plates having an internal configuration allowing the cross circulation of the two gas streams.

This is how we know in particular from document FR-A-2 469 684 a module comprising two sets of plates joined together alternately, each plate being provided with channels internal gas circulation extending substantially longitudinally, parallel and unidirectionally inside said plate, the channels of the plates of one of the assemblies being oriented in the same direction, forming with the direction of orientation of the channels of the plates on the other of the two sets a predetermined angle.

However, such plates generally comprise two external walls, between which the aforementioned channels are defined, and it is understood that the two gas streams circulating, in a crossed fashion, in two consecutive plates, are in fact separated by a double thickness, this which reduces the efficiency of the exchanger.

Document FR-A-2,290,646 discloses a plate exchanger of a different type, the plates used not having a configuration of channels and not being arranged alternately to allow the circulation of two intersecting gas streams.

The document EP-A-0.044.561 also describes a plate exchanger, certain embodiments of which correspond substantially to the teaching of the document FR 2,469,684.

We therefore find here the same drawbacks as those described above with reference to the documents cited.

In addition, certain embodiments in accordance with document EP-A-0.044.561 lead to recuperators having an improved yield to the detriment of the overall mechanical strength.

The present invention aims to solve the aforementioned drawbacks by proposing an energy recuperator of a new design, with improved efficiency, and the mechanical strength of which remains satisfactory.

The solution, in accordance with the present invention, to solve this technical problem consists of a recuperator of the aforementioned type, characterized in that a certain number of plates of the energy exchanger module have at least one recess, obtained in particular by cutting, and thus allowing a better exchange of energy between the gas streams, and in that, in the case where two consecutive plates have a recess, these are separated, so that the gas streams do not mix, by a sheet (7 ) made of a gas-impermeable material, chosen in particular according to its thermal characteristics, and possibly sealed, for example by gluing, on one of these plates.

According to a first embodiment of the invention, all the plates of one of the assemblies forming said energy exchanger module have at least one such recess.

According to another embodiment of the invention, all the plates constituting the energy exchanger module, with the exception of the end plates, have at least one such recess; two consecutive plates being further separated by a sheet made of a gas-impermeable material, chosen in particular as a function of its thermal characteristics, possibly bonded to one of these two plates.

According to a particular characteristic of the invention, the exchanger module further comprises means for modifying the flow rate of the gas streams and / or for creating gas turbulence passing through, these means being preferably arranged at the recessed parts of the plates.

According to a particular embodiment of the invention, the aforementioned means for modifying the flow rate of the gas streams and / or for creating a turbulence of the gases passing through the module, are formed by an element of the same constitution as the plates, which can be attached or obtained during the aforementioned cutting of the plates aiming to create at least one recess.

• La figure 1 est une vue générale de principe, en perspective avec arrachement, d'un module échangeur d'énergie d'un récupérateur à flux croisés selon l'état de la technique ;
• La figure 2 est une vue partielle éclatée d'un module échangeur d'énergie d'un récupérateur selon un premier mode de réalisation de l'invention, montrant trois plaques dont l'une est évidée ;
• Les figures 3a à 3d illustent quatre variantes de réalisation d'une plaque évidée telle que représentée à la figure 2 ou à la figure 4 ; et
• La figure 4 est une vue partielle éclatée d'un module échangeur d'énergie d'un récupérateur conforme à un second mode de réalisation de l'invention, montrant trois plaques évidées, chacune étant pourvue d'une feuille de séparation.

The invention will be better understood, and other objects and advantages thereof will appear more clearly on reading the explanatory description which follows, made with reference to the appended schematic drawings, given solely by way of non-limiting example illustrating several currently preferred embodiments of the invention, and in which:

• Figure 1 is a general view in principle, in perspective with cutaway, of an energy exchanger module of a cross flow recuperator according to the prior art;
• Figure 2 is a partial exploded view of an energy exchanger module of a recuperator according to a first embodiment of the invention, showing three plates, one of which is hollowed out;
• Figures 3a to 3d illustrate four alternative embodiments of a hollow plate as shown in Figure 2 or Figure 4; and
• Figure 4 is a partial exploded view of an energy exchanger module of a recuperator according to a second embodiment of the invention, showing three hollow plates, each being provided with a separation sheet.

FIG. 1 therefore represents an energy exchanger module of a recuperator according to the state of the art closest to the invention.

As we have seen, the energy recuperators known up to now generally comprise one or more energy exchanger modules, arranged and assembled according to arrangements varied.

The module M shown in FIG. 1 comprises two sets of plates 1a, 1b, joined together, for example by gluing or by means of threaded rods passing through all the plates, and of bolts.

Each plate 1a, 1b, has two plane external walls 2, 3, identical and spaced, extending substantially parallel, between which are arranged a set of walls 4a, 4b, longitudinal, parallel and spaced forming a network of internal channels 5a, 5b, of gas circulation extending unidirectionally inside each plate 1a, 1b, respectively.

The walls 4a, 4b, are arranged, in the example shown, transversely to the external walls 3, 4, of each plate, in order to ensure better rigidity.

However, this is only a preferred embodiment, the walls 4 can also be arranged by forming any acute angle with the outer walls 3, 4, mentioned above.

The plates 1a, 1b, can be made of various materials, but, for reasons of rigidity, it will be preferred to use rigid plastics, such as for example polyethylene or polycarbonate. In this case, the plates can be obtained relatively easily by extrusion.

As shown in FIG. 1, the plates 1a, 1b are assembled in an alternating manner, the channels 5a of the plates 1a being oriented in a direction which is substantially normal to the direction of orientation of the channels 5b of the plates 1b.

Again, this is only an embodiment given by way of example, since the angle formed between the directions of orientation of the channels 5a and 5b can of course be different from a right angle.

Thus, as can be understood, the module M is capable of being crossed by two gas streams circulating in a crossed fashion, in directions A and B which correspond to the respective directions of orientation of the channels 5a, 5b, of the plates 1a, 1b.

This module therefore allows the recovery and transfer of calories from one of the gas streams, for example hot stale air leaving an overheated enclosure, to the other gas stream, for example fresh air entering the pregnant. It is obvious that the two gas streams must in no case be brought into contact, and provision will therefore be made for sealing means of the module, well known to those skilled in the art.

It will be noted that all the plates 1a, 1b, forming the module M are identical, and in the example shown have the shape of a square. Generally, the plates will have a general shape of a regular polygon symmetrical with respect to a diagonal, comm for example a square, a hexagon or a rhombus, the production of the module thus requiring the manufacture of only one type of plates.

The plates can also be different, for example in the form of a rectangle.

Referring to Figures 2 and 4, we will now describe the characteristics of an energy exchanger module of a recuperator according to two embodiments of the invention. The general principle governing these new designs is that a better heat exchange is sought between the gas flows or streams passing through the module, without harming the overall rigidity and the tightness of the latter. Indeed, as can be understood with reference to FIG. 1, the gas streams passing through two successive plates 1a, 1b, are separated by a double thickness corresponding to the thickness of the external wall 3 of the plate 1a and to the thickness of the outer wall 2 of the adjacent plate 1b.

The originality of the invention consists in that a certain number of plates of the exchanger module M have at least one recess, obtained in particular by cutting, which will allow better heat exchange between the gas streams, by eliminating the double thickness. mentioned above. The thermal energy savings will be all the more important as said recesses will be important.

Thus, according to a first embodiment of the invention, shown in FIG. 2, all the plates 1b of one of the two above-mentioned assemblies forming the exchanger module M have at least one recess E, extending over a major part of the plate surface.

The shape of this recess, which will preferably be obtained by cutting a plate 1b, as described with reference to FIG. 1, can be entirely arbitrary, for example circular (FIG. 2), rectangular, square, polygonal, etc. The number of recesses can be arbitrary and will essentially depend on the dimensions of the plate. However, for these recessed parts obtained by cutting, in the case where the plates are identical, we will choose symmetrical shapes with respect to the plane perpendicular to said plates, containing the diagonal relative to which said plates are symmetrical.

This embodiment is particularly simple since it only requires the use of two types of plates. It also makes it possible to easily obtain the desired seal both at the level of the whole recuperator and at the level of the plate recesses.

According to a second embodiment of the invention, shown in FIG. 4, all the plates 1a, 1b, constituting the heat exchanger module M, with the exception of the end plates (not shown) have at least one recess E; two consecutive plates 1a, 1b, being separated by a sheet 7 covering the above-mentioned recess (s), and made of a gas-impermeable material, chosen according to its thermal characteristics, for example treated or untreated paper, treated or untreated fabric , nonwoven, metallized or not metallized plastic films, or metallic films, in particular aluminum.

This sheet 7 can be interposed between two plates, then sealed, for example by gluing or welding, to one of the two plates, during the assembly of the plates in module, or previously sealed, for example by gluing or welding, on one of these plates before assembly.

The nature of the sheet 7 can also be chosen as a function of specific objectives relating to the separation of the gas streams. Thus, it is possible to choose a sheet impermeable to gases, but which will allow moisture to pass through, to intervene in particular on the rate of hygrometry. This particular aspect of the invention is not limited to the energy exchanger module of the type represented in FIG. 1, and which constitutes the closest state of the art to the invention, but can be transposed to any type. energy exchanger module, and in particular exchangers with rigid U-shaped separating plates.

In the example shown, the sheet 7 of treated paper is sealed by bonding, before assembly, on one of the external walls of each plate 1a, 1b, so that a single wall (in fact constituted by the sheet 7 ) separates two successive plates 1a, 1b.

According to a particular characteristic of the invention, which applies to the two embodiments described above, the recuperator module M further comprises means for modifying the flow rate of the gas streams and for creating turbulence of the gases passing through it, and these means are preferably arranged at the recessed parts E of the plates.

It is known in fact that the flow variations, or the turbulence of the gases inside the module make it possible to obtain a significant increase in the heat exchanges between the gases passing through the module.

The aforementioned means, for modifying the flow rate of the gas streams and / or for creating a turbulence of the gases passing through the module are preferably formed by an element of the same constitution as a plate, that is to say comprising two parallel external walls in which is disposed a network of internal channels.

These means can be shaped differently from the plates, and produced for example in the form of a strip or bar of cellular material, whether or not honeycombed.

FIGS. 3a to 3d show four alternative embodiments of hollow plates comprising such means respectively referenced 8a to 8d.

As can be seen, these means can be added (8b) and positioned during the assembly of the plates aiming to constitute the module, or obtained during the cutting of the plate (8a, 8c, 8d).

The shape and arrangement of the elements 8a, 8b, 8c, 8d can be arbitrary, for example rectilinear (8b, 8c) or in inverted V (8a).

When the internal channels of the elements 8a, 8b, 8c are open, there is creation at the entry and at the exit of these channels of turbulence of the gases passing through these elements. Part of the internal channels of these elements can be partially or completely blocked (Figure 3d) and this creates variations in the flow of gas streams passing through the plates. Such variations can also be obtained by closing off some of the internal channels 5a, 5b, of the plates, in the most suitable places, for example on the contour of the recessed parts of the plates.

• Ils peuvent être obtenus facilement, à faible coût, à partir des composants habituels des récupérateurs existants ;
• Ils permettent un rendement amélioré avec une séparation des deux flux ou courants gazeux, et une rigidité d'ensemble inchangée.
• Ils peuvent être de grandes dimensions comme de petites dimensions et leurs applications ne sont pas limitées par ces dimensions.

The advantages of the energy recuperators which have just been described are numerous:

• They can be obtained easily, at low cost, from the usual components of existing recuperators;
• They allow an improved yield with a separation of the two gas streams or streams, and an overall rigidity unchanged.
• They can be of large dimensions as well as small dimensions and their applications are not limited by these dimensions.

It should be noted that the energy recuperator in accordance with the present invention is not limited only to the applications described above. In particular, such an energy recuperator can be used in particular as a condenser, for example in combination with machines such as a dryer.

Claims (10)

1. Recuperator of energy intended notably for use in installations for cooling or air-conditioning enclosures such as for example offices, cinemas, theaters and conference halls, sports halls, private or collective dwellings, factories, etc., in which the indoor temperature is different from the outdoor temperature, of the type comprising at least one energy exchanging module through which two streams of gas can flow in crossed fashion without blending, which module is intended for transferring part of the calories from one of said gas stream to the other, and comprises two sets of plates (1a, 1b) fixed side by side in alternating fashion, each plate being provided with internal gas flowing channels (5a, 5b) extending substantially longitudinally, in parallel and unidirectionally inside said plate, the channels (5a) of the plates (1a) of one of the sets being oriented in the same direction which forms a predetermined angle with the direction of orientation of the channels (5b) of the plates (1b) of the other of the two sets, characterized in that at least some of the plates of said module have at least a recess (E) which extends preferably over most of the surface of the plate, which recess is normally obtained by cutting and improves the exchange of energy between the gas streams, end in that, when two consecutive plates are provided with a recess, said plates are separated, so that the gas streams do not blend, by a sheet (7) produced in a gastight material, selected especially as a function of its thermal characteristics, and optionally sealed, for example by bonding, on one of said plates.
2. Recuperator of energy according to claim 1, characterized in that all the plates (1b) of one of said sets forming the exchanger module have at least one recess (E) which preferably extends over most of the surface of the plate.
3. Recuperator of energy according to claim 1, characterized in that all the plates constituting said exchanger module, with the exception of the end plates, have at least one recess (E).
4. Recuperator of energy according to one of claims 1 to 3, characterized in that said module further comprises means (8a, 8b, 8c, 8d) for modifying the flowrate of the gas streams and/or for creating a turbulence of the gases flowing through it, and in that said means are provided at the level of the recessed parts of the plates.
5. Recuperator of energy according to claim 4, characterized in that said means are formed by an element having the same constitution as a plate which can be added or obtained during said cutting of the plate for the purpose of creating at least one recess.
6. Recuperator of energy according to one of claims 1, 2, 4 or 5, characterized in that all said uncut plates comprise two external, flat, identical and spaced out walls (23) extending substantially in parallel and between which a set of spaced out, parallel longitudinal walls (4) is disposed, preferably crosswise, to form said internal channels (5a, 5b).
7. Recuperator of energy according to claim 6, characterized in that said uncut plates are identical and have the general shape of a regular polygon symmetrical with respect to a diagonal, such as for example a square or a lozenge.
8. Recuperator of energy according to one of claims 6 or 7, characterized in that said cut plates are obtained by cutting out parts in said uncut plates.
9. Recuperator of energy according to claim 8, characterized in that said cut out parts in the cut plates are symmetrical with respect to the plane perpendicular to said plates containing the diagonal relatively to which said plates are symmetrical.
10. Recuperator of energy according to claim 3, characterized in that said sheet (7) is produced in a material selected from treated or non-treated paper, treated or non-treated fabric, non-woven, metallized or non-metallized plastic films or metallic films, in particular in aluminium.

Images