FR3138507A1 - Improved indirect evaporative cooling air conditioning system - Google Patents

Abstract

An air conditioning device with indirect evaporative cooling, the device being intended to blow cooled air into a room, the device comprising: an air intake, intended to admit air to be cooled; a plurality of plates, forming a stack, each plate comprising a dry side opposite a wet side, the wet side of each plate being configured to be kept wet by water, each plate being intended to be cooled under the effect from an evaporation of water, from the wet side; the device being such that: two adjacent plates are spaced from one another, along a transverse axis, so as to form a channel, the channel being: either a dry channel, delimited by two dry faces of two adjacent plates, or a wet channel, delimited by two wet faces of two adjacent plates.

Description

Improved air conditioning system using indirect evaporative cooling

The technical field of the invention is an air cooling device by indirect evaporative cooling.

PRIOR ART

Indirect evaporative cooling air coolers, also referred to as indirect adiabatic dew point coolers, have been known for several decades.

The principle of such coolers is schematized on the . It is based on the use of an evapo-exchanger, within which the incoming air (arrow F ₁ in solid line on the ), is cooled, without humidification, potentially to its dew point. Cooling is produced by air circulation in contact with a plate P ₁ , called a cooling plate, cooled by evaporation of water. The cooling plate has a dry side, in contact with which the air to be cooled flows, and a wet side, wetted by water, the water being symbolized by circles on the surface. . On the , the mixed dashed arrows represent cooled or cooling air.

Part of the cooled air, in contact with the dry side of the cooling plate, is evacuated, so as to cool a part: arrow F ₂ . Another part of the cooled air is reinjected into the cooler and directed so as to flow in contact with the wet face of the cooling plate: arrow F ₃ . The air thus reinjected heats up, evaporating the water present on the wet side of the cooling plate. This results in a drop in the temperature of the cooling plate. The air thus heated, loaded with humidity, is then evacuated outside the room.

Compared to the most common air conditioning devices, a notable advantage of such coolers is the absence of refrigerant. These devices must only be powered by water. This results in a more favorable environmental impact than usual air conditioners, based on the compression of a refrigerant. We know that refrigerants can have harmful consequences on the environment.

An example of an indirect cooling device has been described in WO2016134417. In this device, the air to be cooled flows in channels parallel to each other. The same is true for air circulating through channels with wet faces. But the arrangement of coplanar channels, separated from each other, is not optimal in terms of pressure loss.

An example of an indirect evaporative cooling device has been described in application PCT/EP2022/055490. The invention described below is an improvement of this device, making it possible to improve the compactness as well as certain performances, in particular by reducing the pressure losses induced by air flows.

A first object of the invention is an air conditioning device with indirect evaporative cooling, the device being intended to blow cooled air into a room, the device comprising:

• an air intake, intended to admit air to be cooled;
• a plurality of plates, forming a stack, the plates being spaced from each other along a transverse axis, each plate having a dry side opposite a wet side, the wet side of each plate being configured to be wetted by water , each plate being intended to be cooled under the effect of evaporation of water, from the wet side, each plate extending along a longitudinal axis, between a first border and a second border, each border forming a end of the plate in a plane perpendicular to the transverse axis;

the device being such that:

• two adjacent plates delimit a channel, the channel being:
  • either a dry channel, delimited by two dry faces of two adjacent plates,
  • either a wet channel, delimited by two wet faces of two adjacent plates;
• the plates are arranged so as to form an alternation between dry channels and wet channels, each dry channel being adjacent to a wet channel, two adjacent dry and wet channels respectively being connected by a fluid junction;
• each dry channel extends, along the longitudinal axis, between an air inlet, connected to the air intake, and a cold outlet, the cold outlet being intended for an evacuation of cooled air following the air flow in the dry channel;
• each wet channel extends along the longitudinal axis, between the fluid junction and a wet outlet, the wet outlet being intended for an evacuation of humidified air following the flow in the wet channel;

the device being characterized in that:

• two adjacent plates, extending on either side of the same wet channel or the same dry channel are connected by partitions distributed along a lateral axis, perpendicular to the longitudinal axis and to the transverse axis, the partitions closing the wet channel or the dry channel;
• between two adjacent partitions, the respective first edges of said two adjacent plates include a curved part, approaching their respective second edges;
• the respective curved parts of said adjacent plates delimit, along the transverse axis, openings, each opening allowing a passage of air between said plates, between two adjacent partitions.

Thus, at a curved part, the first edge of a plate approaches the second edge of said plate.

According to one possibility:

• the adjacent plates extending on either side of the same wet channel are connected by wet partitions distributed along the lateral axis;
• along the lateral axis, the space between adjacent plates alternately forms wet partitions and wet openings, the wet openings extending, along the transverse axis, between two curved parts of the first edge of each plate, each wet opening forming a wet outlet from the wet channel.

According to one possibility:

• the adjacent plates extending on either side of the same dry channel are connected by drywalls distributed along the lateral axis;
• along the lateral axis, the space between the adjacent plates alternately forms drywalls and dry openings, the dry openings extending, along the transverse axis, between two curved parts of the first edge of each plate, each dry opening forming a dry inlet, intended to admit air to be cooled into the dry channel.

According to one possibility:

• the first respective borders of different adjacent plates, delimiting wet channels and dry channels, comprise a succession of curved parts;
• along the lateral axis, the curved parts of adjacent plates alternately delimit partitions or openings, so that:
  • when the plates delimit a wet channel, each opening forms a wet outlet;
  • when the plates delimit a dry channel, each opening forms a dry entrance;
• along the transverse axis:
  • two adjacent wet outlets are separated by a drywall closing a dry channel;
  • two adjacent dry entrances are separated by a damp wall closing a wet channel.

The distance, along the transverse axis, between two adjacent plates delimiting the same wet channel is variable, such that the distance between said plates can be less, at the level of each wet partition, than the distance between said plates at the level of every wet outing.

The two plates delimiting the same wet channel can come closer to each other at the level of each wet partition.

The distance, along the transverse axis, between two adjacent plates delimiting the same dry channel, is variable, such that the distance between said plates is less, at the level of each dry wall, than the distance between said plates at the level of each dry entrance.

The two plates delimiting the same dry channel can come closer to each other at the level of each drywall.

According to one possibility, each curved part extends, parallel to the longitudinal axis, according to a depth, the depth being greater than or equal to 5 mm or 10 mm or 15 mm. The depth corresponds to a distance, along the longitudinal axis, between the closest and furthest point from the second edge of the plate.

The device may include two joints, parallel to the transverse axis, between two adjacent plates, respectively on either side of the same opening.

According to one possibility, a dry sealing wall, extending along the transverse axis, is arranged:

• facing dry openings of different dry channels, aligned along the transverse axis;
• and facing wet partitions of different wet channels, aligned along the transverse axis;
• so as to distribute air to be cooled towards the different dry channels, the wet partitions and the dry shutter wall confining the air to be cooled between two successive dry channels.

The dry sealing wall can rest on the previously defined joints, each joint extending on either side of the dry openings.

According to one possibility, a wet sealing wall, extending along the transverse axis, is arranged:

• facing wet openings of different wet channels, aligned along the transverse axis;
• and facing drywalls of different dry channels, aligned along the transverse axis;
• so as to evacuate the humid air flowing from the different wet channels, the drywall and the wet shutter wall confining the humid air between two successive wet channels.

The wet seal wall can rest on the previously defined joints, each joint extending on either side of the wet openings.

According to one possibility, at least one wet partition is formed by folding a plate around the lateral axis.

A second object of the invention is a system comprising two devices according to the first object of the invention, in which the devices respectively form a first stack of first plates, and a second stack of second plates, the system being such that the first edge of each plate of the first stack is connected to a first edge of a plate of the second stack, so that:

• the wet openings of two opposing plates face each other;
• the dry openings of two opposite plates are face to face;
• the wet partitions of two opposing plates are face to face;
• drywall from two opposing plates faces each other.

so as to form:

• a humid air collector, extending between wet openings and drywall aligned along the transverse axis;
• a dry air distributor, extending between dry openings and damp partitions aligned along the transverse axis.

The invention will be better understood on reading the presentation of the exemplary embodiments presented, in the remainder of the description, in connection with the figures listed below.

FIGURES

There describes the principles of adiabatic cooling.

There shows an example of a device according to the invention.

There shows an example of the dry side of a plate of the device shown on the .

There shows a sectional view of the device shown on the , along an axis drawn on the .

There shows an example of the wet side of a plate of the device shown on the .

There shows a sectional view of the device shown on the , along an axis drawn on the .

There corresponds to the , on which the air flow through an adjacent dry channel has been superimposed.

There illustrates a configuration according to the prior art, intended to be compared with the .

There shows another example of a wet side of a plate.

There shows another example of the dry side of a plate.

Figures 5A and 5B show an embodiment, in which:

• a wet shutter wall allows collection and evacuation of air circulating in wet channels;
• a dry shutter wall allows distribution of the air to be cooled in dry channels.

There shows a partial three-dimensional view of the configuration shown in Figures 5A and 5B. On the , the dry sealing walls, described in connection with Figures 5A and 5B, have not been shown.

There shows a three-dimensional view of the configuration shown in Figures 5A and 5B.

There represents an embodiment in which each plate has reliefs, making it possible to delimit openings and form partitions.

Figures 7A and 7B illustrate an embodiment comprising an assembly of plates by their respective first edges.

There shows another embodiment, in which the wet partitions delimiting a wet channel are obtained by folding.

PRESENTATION OF SPECIAL MODES OF REALIZATION

Figures 2A to 2F represent an example of a device according to a first embodiment of the invention. Whatever the embodiment, the device 1 comprises a stack of plates 10. The stack may include a few dozen or even hundreds of plates, for example between 30 and 1000 plates 10. The plates 10 are arranged parallel to each other , perpendicular to a transverse axis Z. Each plate 10 extends parallel to a plane P _XY . Each plate extends, parallel to a longitudinal axis , and, parallel to a lateral axis Y, along a width . The stack extends, parallel to the transverse axis Z, at a height . The height depends on the number of plates.

Along the longitudinal axis the second border defines the length of each plate. Thus, each plate is delimited, in a plane perpendicular to the transverse axis Z, by the first border and by the second border, said borders forming a lateral contour of the plate. By lateral contour, we mean a contour extending along the lateral axis Y, and which can be inclined relative to the lateral axis at an angle of inclination less than 90°. Each plate does not extend beyond the first border or beyond the second border: the first border and the second border form ends of the plate.

The length can be between 5 cm and 1m, and preferably between 10 cm and 30 cm. The length is preferably:

• less than the width , for example at least 1.5 times less, or even at least 2 times less or at least 3 times less than the width .
• and/or less than the height , for example at least 1.5 times lower, or even at least 2 times lower or at least 3 times lower than the height .

Two adjacent plates 10 are spaced from one another, parallel to the Z axis, at a distance preferably less than 2 cm, or even less than 1 cm or 0.5 cm. The spacing between two adjacent plates can advantageously be between 0.5 mm and 2 mm. The spacing between two adjacent plates has been exaggerated on the as well as in Figures 2C and 2E.

In the example shown, each plate is flat at each edge. According to possible variants, the edges of two adjacent plates can move closer or further away from each other. An example is described in connection with the . Bringing two adjacent plates together and moving them apart makes it possible to form openings and partitions respectively.

Device 1 is intended to blow cooled air into a room. The air to be cooled is sucked into the device by a ventilation system, not shown, through an intake. The ventilation system includes one or more fans. Depending on the configurations, the air to be cooled comes from outside the room, and/or from inside the room. In this first example, the air is admitted parallel to the longitudinal axis X, as shown in Figures 2A and 2C, in the form of solid arrows. The ventilation system is configured to allow airflow through dry channels and wet channels.

Apart from the first and last plates, delimiting the device along the transverse axis Z, each plate 10 has a wet face 10 _w and a dry face 10 _d . The respectively dry and wet faces of the same plate are opposite, in the sense that they are spaced apart by the thickness of the plate. The thickness of each plate, along the Z axis, is as small as possible, taking into account mechanical strength constraints. The thickness depends on the material forming the plate. It is generally less than 1 cm, and advantageously less than 5 mm, or even 2 mm or 1 mm. The thickness can be between 10 µm and 1 mm, or even between 10 µm and 500 µm. The invention exploits the conduction of heat along the Z axis, through each plate 10.

A 10 _w wet face is intended to be wetted with water as regularly as possible. The water can be placed directly on the plate, or indirectly, the plate comprising, at the wet side, a material, called wet material, soaked in water. It may for example be a material allowing water to be pumped by capillary action, from a water supply. The material may for example include cellulose or a polymer structure. Wetting of a wet face can also be ensured by fluidic channels, provided along the wet face, and allowing pumping of water by capillary action, from the water supply. In the remainder of the description, the term plaque includes a possible capillary structure formed or deposited on the plaque.

The stacking is such that the wet (respectively dry) sides of two consecutive plates face each other. Two wet faces 10 _w , facing each other, and belonging to two adjacent plates, delimit a wet channel 20 _w . Two dry faces 10 _d , facing each other, and belonging to two adjacent plates, delimit a dry channel 20 _d . The channels, dry or wet, are delimited by two lateral uprights, not shown, extending along a plane XZ. The side uprights are spaced from each other by the width of each plate, along the lateral axis Y.

Thus, the stack is formed by an alternation between dry channels 20 _d and wet channels 20 _w . Each dry channel extends, along the longitudinal axis X, between an air inlet 20 _d,in and a cold outlet 20 _d,out . The cold outlet 20 _{d, out} can be intended to be connected to a cooled air exhaust, configured to blow the cooled air inside the room.

Each dry channel 20 _d is connected to an adjacent wet channel 20 _w by a fluid junction 21. Each wet channel 20 _w extends, along the longitudinal axis X, between the fluid junction 21 and a wet outlet 20 _{w, out} . The fluid junction 21 is arranged between the air inlet 20 _d,in and the cold outlet 20 _d,out , or at the level of the cold outlet 20 _d,out . The fluid junction 21 is advantageously closer to the cold outlet 20 _d,out than to the air inlet 20 _d,in . Thus, considering the direction of air flow in the dry channel, the fluid junction 21 is arranged in the dry channel 20 _d , upstream of the cold outlet 20 _{d, out} or at the level of the cold outlet. The device 1 is such that under the effect of the ventilation system, part of the air flowing through a dry channel 20 _d is admitted into a wet channel 20 _w adjacent to it through the fluid junction 21. The fluid junction 21 can be formed by a simple opening made in the plate separating the wet channel from the dry channel. In the examples shown, the fluid junction 21 is formed at a second edge, forming a longitudinal end of the plate. Part of the cooled air is then sucked into at least one wet channel 20 _w adjacent to the dry channel 20 _d , at the level of the cold outlet 20 _{d, out} . The air flow flowing into the wet channel 20 _w is adjusted by the device's ventilation system. This is facilitated by the fact that the flow, in each dry channel, is preferably carried out according to a laminar regime, the air speed being for example between 0.5 ms ^-1 and 3 ms ^-1 .

The fluid junction 21, coupled to the ventilation system, can be such that 50 to 75% of the air flow flows towards the cold outlet 20 _{d, out} , while 25% to 50% of the air flow flows flows through the fluidic junction, towards the wet channel 20 _w . Note that the flow of air through each wet channel 20 _w is carried out in a direction opposite to the flow of air in the dry channel adjacent to it. The device is thus configured to operate against the current.

Preferably, the distance, according to the direction of air flow, in a dry channel 20 _d , between a dry air inlet 20 _{d, in} and a fluid junction 21, is between 5 cm and 1 m, of preferably between 10 and 30 cm. Likewise, the distance, according to the direction of air flow, in a humid channel 20 _w , between the fluid junction 21 and the humid air outlet 20 _{w, out} is between 5 cm and 1m, preferably between 10 and 30 cm.

There shows a perspective view of an example of a device according to the invention. An important aspect of the invention is that for different plates, and preferably for each plate, the first border is not rectilinear along the lateral axis Y. Thus:

• two adjacent plates, extending on either side of the same wet channel 20 _w are connected by wet partitions 13 distributed along the lateral axis Y, the wet partitions closing the wet channel, extending along the transverse axis Z;
• between two adjacent wet partitions, the first respective borders of the adjacent plates delimiting the same wet channel comprise a curved part, approaching their respective second borders;
• each curved part of the first edges delimits, along the transverse axis Z, a wet opening 13', each wet opening allowing air to pass between said plates, in the wet channel 20 _w between two adjacent wet partitions 13. Each wet opening forms a 20 _{w wet outlet,out} of the wet channel.

and or

• two adjacent plates, extending on either side of the same dry channel 20 _d are connected by dry walls 15 distributed along the lateral axis Y, the dry walls closing the dry channel, extending along the transverse axis Z;
• between two adjacent drywalls, the first edges of the adjacent plates delimiting the same dry channel include a curved part, approaching their respective second edges;
• each curved part of the first edges delimits, along the transverse axis Z, dry openings 15', each dry opening allowing air to pass between said plates, in the dry channel 20_dbetween two adjacent drywalls 15. Each dry opening 15’ forms a dry air inlet 20_{d, in} of the dry channel.

In the example shown on the , each curved part forms, in a plane P _XY perpendicular to the transverse axis, a triangular shape.

We understand from the above that the length of each plate is variable: it extends between a maximum length, between the curved parts, and a minimum length, in each curved part.

There shows an example of a dry face 10 _d of a plate 10 delimiting a dry channel 20 _d of the device shown on the . As previously indicated, the plate 10 extends between a first border 11 and a second border 12. We have shown, on the , air flows along the dry channel 20 _d . Air is admitted into the dry channel 20 _d through the dry openings 15', bypassing the dry walls 15. The dry openings 15' are distributed along the lateral axis Y; they form the air inlets 20 _d,in of the dry channel. The air flows to a cold outlet 20 _d,out .

There is a cross section of a device according to the invention, in a plane passing through the axis in phantom drawn on the . In this figure, we observe a superposition of plates, forming an alternation between dry channels 20 _d and wet channels 20 _w . In this section plane, the dry air inlet 20 _d,in of each dry channel 20 _d is obstructed by a dry wall 15. Air is admitted into each dry channel 20 _d through dry openings 15', distributed along the lateral axis Y, between the drywalls 15.

There shows an example of a wet face 10 _w of a plate 10, delimiting a wet channel 20 _w , forming the device shown on the . We represented, on the , air flows along the wet channel 20 _w . The air evacuates from the wet channel 20 _w , through the wet openings 13', bypassing the wet partitions 13. The wet openings 13' are distributed along the lateral axis Y, between each wet partition 13.

The management of humid air flows and air to be cooled can be ensured by a collection zone 22 and a distribution zone 22'. The collection zone 22 ensures the collection of humid air evacuating from the humid channels 20 _w . The distribution zone 22' allows the distribution of air to be cooled in the different dry channels 20 _d . The collection zone 22 and the distribution zone 22' are shown in Figures 2C and 2E.

There is a cross section of a device according to the invention, in a plane passing through the axis in phantom drawn on the . In this figure, we observe a superposition of plates, forming an alternation between dry channels 20 _d and wet channels 20 _w . In this sectional plane, the wet outlet 20 _{w, out} of each wet channel 20 _w is obstructed by a wet partition 13. The air evacuates from each wet channel 20 _w through wet openings 13', distributed according to the lateral axis Y, between the wet partitions 13.

If we take into account two adjacent dry and humid channels respectively, the distribution of the dry openings, through which the air to be cooled is admitted into the dry channel, and of the humid openings, through which the hot and humid air enters. evacuates from the wet channel, favors a counter-current fluid configuration. According to such a configuration, the air circulates along a dry channel, parallel to, and in the opposite direction, the air circulating along the adjacent wet channel. There show it , on which the air circulation in the adjacent dry channel has been superimposed, as it appears on the . It is observed that counter-current circulation is obtained over most of the length of the channels.

In the configuration described in connection with Figures 2A to 2F, each opening, whether a dry or wet opening, is formed between the first edges of two adjacent plates, at the level of curved parts of said plates. It is recalled that in each curved part of a plate, the length of the plate, that is to say the distance, along the longitudinal axis X, between the first border and the second border, is less than the maximum length of the plate. That is, in each curved part, the first border approaches the second border.

In comparison with the configuration described in applications PCT/EP2022/055490 and WO2016134417, the presence of each curved part makes it possible to optimize the thermal length _th of the device, that is to say the length along which the air flows in a dry channel and in an adjacent wet channel are parallel and in opposite directions. The ratio between the thermal length and the maximum length of each plate, along the X axis, is higher thanks to the presence of the curved parts. Thus, the “useful” portion of the plates, that is to say that contributing to heat exchange, is optimal.

There schematizes a 10 _d-AA plate delimiting a dry channel representative of the prior art as described in application PCT/EP2022/055490. The solid arrows represent hot air intended to be cooled, and entering the dry channel. The mixed dashed arrows schematize the air flowing in the dry channel. The air admitted into the dry channel bypasses transverse channels C, the latter collecting the humid air flowing from an adjacent wet channel. The dashed arrows symbolize moist air flowing through the adjacent moist channel. In the wet channel, the air is evacuated through the transverse channels C. We observe that the hatched zone of the dry channel does not contribute, or in a negligible way, to the heat exchange.

An advantage of the curved parts of the plates, delimiting openings through which dry air or humid air flows, is to optimize the quantity of material used. In fact, it involves removing the material which, on each plate, is useless, or of little use, for heat exchange, that is to say the hatched portion represented on the . This reduces the quantity of unnecessary material and reduces the pressure loss. On the , we have represented, by hatching, “useless” material which would be present if we had rectangular plates, as described in the prior art. Removal of unnecessary material results in curved parts. The inventor estimates that by removing the quantity of unnecessary material, the pressure loss can be reduced by approximately 5% to 10%.

Each notch can extend, along the longitudinal axis, to a depth p greater than or equal to 5 mm, or even 10 mm, or even 15 mm, regardless of the shape of the notch. By depth of a notch , we mean the difference, along the longitudinal axis X, between the closest and furthest point from the second border. The depth has been schematized by a double arrow on the , on which we have also indicated the first border 11 and the second border 12.

In the configuration shown in Figures 2A to 2F, the curved parts have, in the plane of the plates, triangular shapes. Other forms are possible. In Figures 4A and 4B, plates are shown whose first edges define curved parts whose shape is ellipsoidal. According to a variant not shown, the edges forming the curved parts are in the shape of a crenel.

Another advantage is the presence of curved parts facilitates the arrangement of a shutter wall, described below, in connection with Figures 5A and 5B, to distribute the air to be cooled in different dry channels or evacuate the air wet from different wet channels.

We observe that the width, along the lateral axis Y, is greater for the 15' dry openings than for the 13' wet openings. This takes into account the fact that only part of the air entering a dry channel is returned to the wet channel. The dimension, along the lateral Y axis, of the dry and wet openings is determined to take into account the fact that the flow of air to be cooled is generally 2 to 3 times greater than the flow of humid air leaving the wet channels.

Figures 5A and 5B schematize a configuration according to which the wet openings and the dry walls formed at each curved part are closed by a wet sealing wall 18. Each wet sealing wall 18 makes it possible to form a collector, allowing to collect the humid air resulting from wet channels, and to transport the humid air, in a sealed manner, through the dry channels. The wet closing walls 18 can be grouped together to form a wet collector, the latter being intended to be applied against the respective first edges of each plate, to close each wet opening and each dry wall. Applying the wet collector against the plates allows the wet openings to be closed.

Complementarily or alternatively, the device can also include a dry sealing wall 19. The dry sealing wall 19 is applied against the dry openings 15' of different dry channels, and against the wet partitions 13 of different wet channels. . This allows the air to be cooled to be transported through wet channels and diffused into the dry channels, through the dry openings.

Each dry shutter wall 19 makes it possible to distribute the air to be cooled along the transverse axis Z, and towards the different dry channels. Each humid shutter wall 18 makes it possible to collect the humid air resulting from different humid channels and to direct it along the transverse axis.

In Figures 5A and 5B, the closing walls are ellipsoidal. Alternatively, they can be flat. Such a possibility is illustrated and schematized by a dotted line in Figures 5A and 5B. We then take advantage of the presence of the curved parts, which make it possible to form a sufficient space to collect air (facing a wet opening), or to distribute air (through a dry opening) or to confine the air. air (between a blanking wall and a dry or wet wall). This results in a gain in compactness of the device, the dimension along the longitudinal axis being able to be reduced.

On the , we have shown the configuration shown in Figures 5A and 5B, by removing the dry sealing walls. On the , the dry sealing walls are shown. Figures 5C and 5D make it possible to visualize the circulation of air in the dry channels, between the inlets 20 _{d, in} and the outlets 20 _{d, out} of the dry channels. They also make it possible to visualize the circulation of air along the wet channels, between the 20 _{w inlets, in} 20 _{w outlets, out} of the wet channels.

In the preceding embodiments, the plates 10 are flat. The partitions, dry or wet, extend along the transverse axis, so as to connect two adjacent plates between two wet openings 13' or between two dry openings 15'.

There illustrates a variant according to which the plates are not flat. The distance, parallel to the transverse axis, between two adjacent plates delimiting the same wet channel is variable, such that the distance between said plates is less at the level of each wet partition 13 than at the level of each wet opening 13' : Thus, the distance between the two plates varies between a minimum distance and a maximum distance. When the distance is minimum, a damp wall 13 is formed between the plates. The two plates can be in contact with each other, in which case the contact between the two plates forms the wet partition 13. In the example shown in the , each damp wall results from a rapprochement between two adjacent plates.

Analogously, the distance between two adjacent plates delimiting the same dry channel is variable, such that the distance between said plates is less at the level of each dry wall 15 than at the level of each dry opening 15': Thus, the distance between the two plates varies between a minimum distance and a maximum distance. When the distance is minimal, a drywall 15 is formed between the plates. The two plates may be in contact with each other, in which case the contact between the two plates forms the drywall. In the example shown on the , each drywall 15 results from a rapprochement between two adjacent plates.

The assembly between the close parts of two adjacent plates can be obtained by thermoforming. On the , the gray areas correspond to a joint against which a sealing wall can be applied.

There shows an assembly of two plates 10 ₁ and 10 ₂ , each plate being as described in connection with Figures 2A to 2F. The plates are assembled together by their respective first edges 11 ₁ , 11 ₂ . The plates demarcate a wet channel. The first plate 10 ₁ has a first edge 11 ₁ arranged against the first edge 11 ₂ of the second plate 10 ₂ .

The first edge 11 ₁ of the first plate 10 ₁ comprises curved parts 13 ₁ , forming wet partitions. The first edge 11 ₂ of the second plate 10 ₂ comprises curved parts 13 ₂ , forming wet partitions. When assembling the first edges 11 ₁ , 11 ₂ respectively of the first plate and the second plate, the wet partitions face each other. This makes it possible to form a distributor of air to be cooled, extending around an axis parallel to the transverse axis, that is to say perpendicular to the plates 10 ₁ and 10 ₂ . The air to be cooled distributor allows the admission of air to be cooled transversely to the wet channel, towards an adjacent dry channel.

The first edge 11 ₁ of the first plate 10 ₁ comprises curved parts 13' ₁ , forming wet openings. The first edge 11 ₂ of the second plate 10 ₂ comprises curved parts 13' ₂ , forming wet openings. The assembly of the respective first edges 11 ₁ , 11 ₂ of the first plate and the second plate makes it possible to form a humid air collection zone, extending around an axis parallel to the transverse axis, c that is to say perpendicular to the plates 10 ₁ and 10 ₂ . The collection zone allows the evacuation of the air having flowed into the wet channel, the flow of which is represented on the , through a collector as described in connection with the .

Seals 19 ensure sealing during assembly of the first edges 11 ₁ , 11 ₂ .

There shows a system comprising an assembly of two plates 10 ₁ and 10 ₂ , each plate being as described in connection with Figures 2A to 2F. The plates are assembled together by their respective first edges 11 ₁ , 11 ₂ . The plates demarcate a dry channel. The first plate 10 ₁ has a first edge 11 ₁ arranged against the first edge 11 ₂ of the second plate 10 ₂ .

The first edge 11 ₁ of the first plate 10 ₁ comprises curved parts 15 ₁ , forming drywalls. The first edge 11 ₂ of the second plate 10 ₂ comprises curved parts 15 ₂ , forming drywalls. The assembly of the respective first edges 11 ₁ , 11 ₂ of the first plate and the second plate makes it possible to form a sealed collector, allowing the evacuation of humid air coming from a collection zone, as described in link with the , of an adjacent wet channel. The collector extends around an axis parallel to the transverse axis, that is to say perpendicular to the plates 10 ₁ and 10 ₂ .

The first border 11₁of the first plate 10₁features curved parts 15’₁, forming dry openings. The first border 11₂of the second plate 10₂features curved parts 15’₂, forming dry openings. Assembling the first edges 11₁.11₂ respective of the first plate and the second plate makes it possible to form a distributor of air to be cooled in the dry channel, the flow of which is shown schematically by mixed dashed lines.

There represents an embodiment in which several wet channels 20 _w are delimited by wet partitions 13 obtained by folding the same plate 10, around the lateral axis Y. The folding of the plate makes it possible to face each other screw the wet sides of said plate. This allows the 10 _w wet faces delimiting the same wet channel to be placed opposite each other. The formation of a damp partition by folding is considered an advantageous alternative to the formation of a damp partition by heat-sealing two opposite damp faces 10 _w , as described in connection with the . Each 10 _w wet face is usually covered with a damp material, intended to moisten, for example paper. However, such a material is not very compatible with heat-sealing processes, due to adhesion difficulties. Thus, when one wishes to obtain a wet partition by thermoforming, it is necessary to locally remove the material covering the wet faces. Folding prevents such shrinkage. Thus, it is not necessary to delimit, on each opposite wet face, an area within which the wet material is removed.

In the embodiment shown on the , the drywalls 15 are obtained by heat-sealing two opposite dry faces _10d delimiting a dry channel _20d .

Claims (14)

Air conditioning device (1) with indirect evaporative cooling, the device being intended to blow cooled air into a room, the device comprising:

• an air intake, intended to admit air to be cooled;
• a plurality of plates (10), forming a stack, the plates being spaced from each other along a transverse axis (Z), each plate comprising a dry face (10 _d ) opposite a wet face (10 _w ), the face wet of each plate being configured to be wetted by water, each plate being intended to be cooled under the effect of evaporation of water, from the wet face, each plate extending along a longitudinal axis , between a first border and a second border, each border forming one end of the plate in a plane perpendicular to the transverse axis;

the device being such that:

• two adjacent plates delimit a channel, the channel being:
  • either a dry channel (20 _d ), delimited by two dry faces (10 _d ) of two adjacent plates,
  • either a wet channel (20 _w ), delimited by two wet faces (10 _w ) of two adjacent plates;
• the plates are arranged so as to form an alternation between dry channels and wet channels, each dry channel being adjacent to a wet channel, two adjacent dry and wet channels respectively being connected by a fluid junction (21);
• each dry channel (20 _d ) extends, along the longitudinal axis (X), between an air inlet (20 _{d, in} ), connected to the air intake, and a cold outlet (20 _{d, out} ), the cold outlet being intended for an evacuation of cooled air following the flow of air in the dry channel;
• each wet channel (20 _w ) extends along the longitudinal axis, between the fluid junction (21) and a wet outlet (20 _{w, out} ), the wet outlet being intended for an evacuation of humidified air following the flow in wet channel;

the device being characterized in that:

• two adjacent plates, extending on either side of the same wet channel or the same dry channel are connected by partitions (13, 15) distributed along a lateral axis (Y), perpendicular to the longitudinal axis (X) and the transverse axis (Z), the partitions closing the wet channel or the dry channel;
• between two adjacent partitions, the respective first edges of said two adjacent plates comprise a curved part, approaching their respective second edges;
• the respective curved parts of said adjacent plates delimit, along the transverse axis (Z), openings, each opening allowing a passage of air between said plates, between two adjacent partitions.

Device according to claim 1, in which:

• the adjacent plates extending on either side of the same wet channel (20 _w ) are connected by wet partitions (13) distributed along the lateral axis;
• along the lateral axis (Y), the space between adjacent plates alternately forms wet partitions (13) and wet openings (13'), the wet openings extending along the transverse axis (Z) , between two curved parts of the first edge of each plate, each wet opening forming a wet outlet from the wet channel.

Device according to claim 1 or claim 2, in which:

• the adjacent plates extending on either side of the same dry channel are connected by dry walls (15) distributed along the lateral axis;
• along the lateral axis (Y), the space between the adjacent plates alternately forms the drywalls (15) and dry openings (15'), the dry openings extending, along the transverse axis, between two curved parts of the first edge of each plate, each dry opening forming a dry inlet, intended to admit air to be cooled into the dry channel.

Device according to claims 2 and 3, in which:

• the first respective borders of different adjacent plates, delimiting wet channels and dry channels, comprise a succession of curved parts;
• along the lateral axis, the curved parts of adjacent plates alternately delimit partitions or openings, so that:
  • when the plates delimit a wet channel, each opening forms a wet outlet;
  • when the plates delimit a dry channel, each opening forms a dry entrance;
• along the transverse axis:
  • two adjacent wet outlets are separated by a drywall closing a dry channel;
  • two adjacent dry entrances are separated by a damp wall closing a wet channel.

Device according to claim 4, in which the distance, along the transverse axis, between two adjacent plates delimiting the same wet channel is variable, such that the distance between said plates is less, at the level of each wet partition, than the distance between said plates at each wet outlet. Device according to claim 5, in which the two plates delimiting the same wet channel come closer to each other at the level of each wet partition. Device according to any one of claims 5 and 6, in which the distance, along the transverse axis (Z), between two adjacent plates delimiting the same dry channel, is variable, such that the distance between said plates is less , at each drywall at the distance between said plates at each dry entrance. Device according to claim 7, in which the two plates delimiting the same dry channel come closer to each other at the level of each dry wall. Device according to any one of the preceding claims, in which each curved part extends, parallel to the longitudinal axis, according to a depth (p), the depth being greater than or equal to 5 mm or 10 mm or 15 mm . Device according to any one of the preceding claims, in which two joints, parallel to the transverse axis, extend between two adjacent plates, respectively on either side of the same opening. Device according to any one of the preceding claims, in which a dry sealing wall (19), extending along the transverse axis, is arranged:

• facing dry openings (15') of different dry channels, aligned along the transverse axis;
• and facing wet partitions (13) of different wet channels, aligned along the transverse axis;
• so as to distribute air to be cooled towards the different dry channels, the wet partitions and the dry shutter wall confining the air to be cooled between two successive dry channels.

Device according to any one of the preceding claims, in which a wet sealing wall (18), extending along the transverse axis, is arranged:

• facing wet openings (13') of different wet channels, aligned along the transverse axis;
• and facing drywalls (15) of different dry channels, aligned along the transverse axis;
• so as to evacuate the humid air flowing from the different wet channels, the drywall and the wet shutter wall confining the humid air between two successive wet channels.

Device according to any one of the preceding claims, in which at least one wet partition (13) is formed by folding a plate around the lateral axis. System comprising two devices according to any one of claims 1 to 13, in which the devices respectively form a first stack of first plates, and a second stack of second plates, the system being such that the first edge of each plate of the first stack is connected to a first edge of a plate of the second stack, so that:

• the wet openings of two opposing plates face each other;
• the dry openings of two opposite plates are face to face;
• the wet partitions of two opposing plates are face to face;
• drywall from two opposing plates faces each other.

so as to form:

• a humid air collector, extending between humid openings and drywalls aligned along the transverse axis;
• a dry air distributor, extending between dry openings and damp partitions aligned along the transverse axis.