Indirect evaporative cooling system

Abstract

Indirect evaporative cooling air conditioning device (1) comprising: an air inlet; a plurality of plates (10), forming a stack (30), the plates being spaced from each other along a transverse axis (Z), each plate having a dry face (10d) opposite a wet face (10w), the wet face of each plate being configured to be wetted by water, each plate being intended to be cooled by the effect of water evaporation, from the wet face, each plate extending along a longitudinal axis, between a first border and a second border, each border forming an end of the plate in a plane perpendicular to the transverse axis; the device comprises, at each wet face, a first capillary structure, formed of a first capillary material, each wet face being covered by a second capillary structure, extending to the first capillary structure.

Description

Title of the invention: Air conditioning device using indirect evaporative cooling Technical field

[0001] The technical field of the invention is an air cooling device by indirect evaporative cooling. PREVIOUS ART

[0002] Indirect evaporative cooling air coolers, also referred to as indirect adiabatic dew point coolers, have been known for several decades.

[0003] The principle of such coolers is shown schematically in [Fig. 1]. It is based on the use of an evaporator exchanger, within which the incoming air (dotted Dien arrow in [Fig.l]), is cooled, without humidification, potentially down to its dew point. Cooling is produced by air circulation in contact with a Pb plate called a cooling plate, cooled by water evaporation. The cooling plate has a dry face, in contact with which the air to be cooled flows, and a face, called a wet face, wetted by water, the water being symbolized by circles in [Fig.l]. In [Fig.l], the dashed arrow corresponds to the air to be cooled, the mixed dashed arrow represents the cooled air or air in the process of cooling, the solid arrow corresponds to the air circulating in the humid channel, and the evaporation of which causes cooling of the plate. This nomenclature is retained on the application.

[0004] A portion of the cooled air, in contact with the dry face of the cooling plate, is evacuated, so as to cool a room: arrow D2. Another portion 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 D3. The air thus reinjected heats up, evaporating the water present on the wet face of the cooling plate: arrow D4. 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.

[0005] Compared to the most common air conditioning devices, a notable advantage of such coolers is the absence of refrigerant. These devices only need to be powered by water. This results in a more favorable environmental balance than conventional air conditioners, based on compression of a refrigerant. It is known that refrigerants can have harmful consequences on the environment.

[0006] Examples of indirect cooling devices have been described in WO2016134417 and in WO2022184871.

[0007] An important aspect of this type of device is the need to maintain wetted faces, in contact with which the water can be evaporated upon contact with the air, which generates the cooling of the plate. This assumes appropriate management of a liquid phase, for example water, so as to maintain sufficient humidity along the wetted faces of a multitude of channels. The invention described below meets this need. Statement of the invention

[0008] 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 comprising a dry face opposite a wet face, the wet face 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;

[0009] the device being such that, in the stack: - 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; - each dry channel extends, along a longitudinal axis, between an air inlet (20 djn), connected to the air intake, and a cold outlet (20d.out), the cold outlet being intended for evacuation of cooled air following the flow of air in the dry channel; - each wet channel (20w) extends along the longitudinal axis, between a wet inlet (20Wjin) and a wet outlet (20WjOUt), the wet outlet being intended for evacuation of humidified air following the flow in the wet channel, the wet channel being configured so as to receive a portion of the air emerging from the dry channel;

[0010] the device being characterized in that: - each wet channel comprises a first capillary structure, formed from a first capillary material, configured to be wetted by water, the first capillary structure being arranged in contact with at least one wet face delimiting each wet channel; - at least one wetted face of each wet channel comprises a second capillary structure, the second capillary structure extending from the first capillary structure, along the wetted face, the second capillary structure being thinner than the first capillary structure; - the stack comprises a water inlet, configured to receive water, the water inlet being in fluid contact with at least a first capillary structure.

[0011] The second capillary structure may be formed from a second capillary material, different from the first capillary material. The second capillary material may be a woven or non-woven fabric or a paper.

[0012] Preferably, the capillary rise height of the first capillary material is less than the capillary rise height of the second capillary material, the capillary rise height corresponding to a height reached, by capillary pumping, in the first or second material arranged vertically.

[0013] The second capillary structure can be formed by structuring each wet face.

[0014] According to one possibility, two first capillary structures, extending along two adjacent wet channels, are in contact with each other, so as to allow circulation of water from one first capillary structure to the other. The contact between the first capillary structures can be carried out by direct contact or by a capillary connecting material.

[0015] Each wet channel may be delimited by two lateral borders, extending parallel to the longitudinal axis, each wet channel comprising a first capillary structure extending along at least one lateral border.

[0016] The first capillary structure of at least one wet channel may extend, along the transverse axis, with a thickness greater than 0.3 mm and / or less than 10 mm.

[0017] The second capillary structure covering the wetted faces of at least one wet channel can extend, along the transverse axis, with a thickness of less than 1000 μm.

[0018] According to one possibility: - each wet channel in the stack is assigned a row, the row increasing with the distance, along the transverse axis, from the water inlet; - the wet channel of rank 1 is adjacent to the water inlet; - two first successive capillary structures, arranged respectively in two wet channels of successive rows are in fluidic contact with each other.

[0019] The fluid contact may be effected by direct contact of the first two successive capillary structures or by an auxiliary material, extending between the first two capillary structures, so that when the transverse axis is vertical, water, admitted through the water inlet, flows by gravity and by capillarity between the first two successive capillary structures.

[0020] The device may comprise: - a water outlet configured to allow a flow of water flowing from the first maximum rank capillary structure; - a receptacle, intended to receive the water flowing through the water outlet - a pump, configured to pump the water collected in the receptacle, so as to admit the water into the fluid water inlet.

[0021] The pump may be configured to sequentially pump water collected in the receptacle FIGURES

[0022] [Fig.l] describes the principles of adiabatic cooling.

[0023] [Fig.2] shows an example of stacking plates, forming dry channels and wet channels.

[0024] Figures 3A, 3B, 3C represent a wet channel according to one embodiment.

[0025] [Fig.3D] shows a diagram of a wet channel according to a variant of the embodiment described in connection with Figures 3A to 3C.

[0026] [Fig.4] shows a top view of a wetted face of a plate.

[0027] Figures 5A to 5E represent an example of a stack of plates. Figures 5A to 5E show the outlet, called the cold outlet, of each dry channel of the stack, as well as the inlet, called the wet inlet, of each wet channel.

[0028] [Fig.5F] shows a device comprising four stacks.

[0029] [Fig. 6] shows the stack shown schematically in Figures 5A to 5E. In [Fig. 6], we are facing the outlet, called the wet outlet, of each wet channel of the stack, as well as the inlet of each dry channel. PRESENTATION OF SPECIAL EMBODIMENTS

[0030] [Fig.2] shows a detail of a stack 2 of plates of a device which is the subject of the invention. The device is intended to blow cooled air into a room.

[0031] By room is meant an enclosure whose air is to be cooled. The room may be a room in a building, of the residential or industrial type, or a room in a means of transport, for example a cabin of a vehicle.

[0032] The geometry of the stack is similar to that described in application WO2022184871. Figure 2 shows 4 plates. The stack may comprise 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 PXY. Each plate extends, parallel to a longitudinal axis X, along a length l, and, parallel to a lateral axis Y, along a width L. The stack extends, parallel to the transverse axis Z, along a height h. The height h depends on the number of plates. The length / , the width L and the height h are shown in [Fig.5A]. The stack is delimited by a lower plate and an upper plate.

[0033] During operation of the device, the Z axis is assumed to be vertical, oriented upwards, to within ± 30° or within ± 10°. This allows water to flow by gravity from the upper plate to the lower plate, as described later.

[0034] Each plate 10 has a wet face 10w and a dry face 10d. The dry and wet faces respectively of the same plate are opposite, in the sense that they are distant from each other by the thickness of the plate. The thickness of each plate, along the Z axis, is as small as possible, taking into account the mechanical strength constraints. The thickness depends on the material forming the plate. 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.

[0035] The stack is such that the wet (respectively dry) faces of two consecutive plates face each other. Two wet faces 10w, facing each other, and belonging to two adjacent plates, delimit a wet channel 20w. Two dry faces 10d, facing each other, and belonging to two adjacent plates, delimit a dry channel 20d.

[0036] Each wetted face 10w is intended to be, as regularly as possible, wetted with water. An important aspect of the patent application concerns the way in which the humidity is maintained on the plate.

[0037] In [Fig.2], each plate has been assigned a rank n, n being a natural integer, n is incremented between two successive plates along the Z axis, in the opposite direction to the Z axis. Thus, the plates 10n, 10n+i, 10n+2 and 10n+3 have been represented. Each plate has a wet face, indicated by the index w, and a dry face, indicated by the index d. The wet faces 10n>w, 10n+ijW, of the respective plates 10n, 10n+i delimit a wet channel 20w. The dry faces 10n+i>d, 10n+2jd, of the respective plates 10n+i, 10n+2 delimit a dry channel 20d. The wet faces 10n+2jW, 10n+3jW, of the respective plates 10n+2, 10n+3 delimit a wet channel 20w.

[0038] Thus, the stack is formed by alternating dry channels 20d and wet channels 20w. Each dry channel extends, along the longitudinal axis X, between a hot inlet 20djin, through which the hot air to be cooled flows, and an outlet cold 20djOUt. The ventilation system is configured to allow airflow through dry channels and wet channels. The cold 20djOUt outlet can be intended to be connected to a cooled air exhaust, configured to blow the cooled air into the room.

[0039] The air to be cooled is blown or sucked into the device by a ventilation system, not shown in [Fig. 2], through an inlet. The ventilation system comprises one or more fans. In the example of [Fig. 2], the air to be cooled is admitted parallel to a longitudinal axis X.

[0040] Each dry channel 20d is connected to an adjacent wet channel 20w by a fluid junction 20'. Each wet channel 20w extends, along the longitudinal axis X, between the fluid junction 20' and a wet outlet 20WjOUt. The fluid junction 20' is arranged between the air inlet 20djin and the cold outlet 20djOUt, or at the cold outlet 20djOUt. The fluid junction 20' is advantageously closer to the cold outlet 20djOUt than to the hot inlet 20djin. Thus, considering the direction of air flow in the dry channel, the fluid junction 20' is arranged in the dry channel 20d, upstream of the cold outlet 20djOUt or at the cold outlet. The device 1 is such that under the effect of the ventilation system, a portion of the air flowing through a dry channel 20d is admitted into a wet channel 20w adjacent to it through the fluid junction 20'.The fluid junction 20' may 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 20' is formed at a longitudinal end of the plate. A portion of the cooled air is then drawn into at least one wet channel 20w adjacent to the dry channel 20d, at the cold outlet 20djOUt. The air flow rate flowing in the wet channel 20w is adjusted by the ventilation system of the device. 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 '. .

[0041] The fluid junction 20', coupled to the ventilation system, may be such that 50 to 75% of the air flow flows toward the cold outlet 20djOUt, while 25% to 50% of the air flow flows through the fluid junction, toward the wet channel 20w. It is noted that the air flow through each wet channel 20w, represented by solid arrows in [Fig. 2], is carried out in a direction opposite to the air flow in the dry channel adjacent to it, the latter being represented by a dashed arrow in [Fig. 2]. The device is thus configured to operate counter-currently. The cooled air, emanating from each dry channel, is represented by a dot-dash arrow.

[0042] In the following figures, the legend associated with the arrows, representing the flows, is identical: dashed arrow for dry air, mixed dashed arrows for cooled air, and solid line arrows for humid air.

[0043] The length l can be between 5 cm and 1 m, and preferably between 10 cm and 30 cm. The length / is preferably: - less than width I, for example at least 1.5 times less, or even at least 2 times less or at least 3 times less than width L. - and / or lower than the height h, for example at least 1.5 times lower, or even at least 2 times lower or at least 3 times lower than the height h.

[0044] Two adjacent plates 10n, 10n+i are spaced apart from each other, parallel to the Z axis, by 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.

[0045] Figures 3A to 3C show two plates 10n, 10n+i according to a first embodiment. In [Fig.3A], the dry face 10d>n of the plate 10n can be seen. The respective wet faces 10w>net 10w n+i of the plates 10n, 10n+i delimit a wet channel 20w. The latter extends between a wet inlet 20Wjin and a wet outlet 20WjOUt. Each outlet 20WjOUt is formed at a notch 17 made on the plates. A notch corresponds to a localized reduction in the length of the plate. Between two successive notches, along the lateral axis, two successive plates delimiting a wet channel are joined to each other, which forms a wet partition 13. At each notch 17, the successive plates delimiting a wet channel 20w are spaced from each other, so as to define an opening 13' forming a wet outlet 20WjOUt. Such a configuration is described in more detail in application FR2207710.

[0046] Each plate is delimited by two lateral edges 11, 12 extending parallel to the longitudinal axis X, and spaced from each other along the lateral axis Y. At each lateral edge 11, 12, a wet channel is delimited by a first capillary structure 21. The first capillary structure 21 is formed by a first capillary material, spongy, allowing diffusion of liquid, in this case water, by capillarity, as well as storage of said liquid. In this example, the liquid considered is water, which constitutes the preferred embodiment, without excluding the possibility of using another liquid.

[0047] The term capillary material designates a material permeable to a liquid, and allowing diffusion of the liquid by capillarity, which generates a capillary pumping phenomenon. By capillary structure, we mean a structure allowing capillary pumping of a liquid.

[0048] Each first capillary structure 21 extends along the entire lateral edge of the wet channel. The thickness of each first capillary structure, defined along the transverse axis Z, is preferably greater than 0.3 mm or 0.5 mm. Preferably, the thickness of each first capillary structure is less than 5 or 10 mm. The thickness range 0.5 mm - 5 mm is considered optimal. Preferably, the thickness of each first capillary structure 21 is such that the first capillary structure is in contact with the two wetted faces delimiting a wet channel.

[0049] Advantageously, the first material may have a capillary rise height of the order of a few centimeters. By capillary rise height is meant a height at which the water migrates, by capillary pumping, into the first material kept vertical.

[0050] [Fig.3B] shows an example of a wetted face 10w n+i of the plate 10n+i shown in [Fig.3A]. Along the lateral axis Y, each first capillary structure 21 extends with a width of between 1 mm and 30 mm, preferably between 3 mm and 10 mm. Each first capillary structure 21 is intended to form a water buffer reservoir, at each wet channel. The fact that each first capillary structure forms a buffer reservoir makes it possible to avoid a continuous supply of water.

[0051] In this example, each first capillary structure 21 extends, along the longitudinal axis X, along two opposite longitudinal ends 21x. In the example shown, the water feeds each first capillary structure 21, by capillarity, from each longitudinal end 21x, along the arrows Fi. The migration takes place parallel to the longitudinal axis X.

[0052] The water supply of the first capillary structures belonging to adjacent wet channels is described below, in connection with [Fig.5A]: the first capillary structures 21 of two adjacent wet channels, aligned along the Z axis, are in contact with each other, so as to allow circulation of water from one first capillary structure to the other, the contact between said first capillary structures forming a fluidic contact (or bridge).

[0053] The wet face 10wn+i is coated with a second capillary structure 22 formed from a second capillary material. In this example, the second capillary structure is a thin sheet of the second material. The second capillary structure 22 is arranged in contact with the plate 10n+i. The second capillary structure 22 extends from at least one first capillary structure 21. In the example shown in [Fig.3B], the second capillary structure 22 extends between the two first capillary structures 21, the latter forming the lateral borders of the wet channel. The thickness of the second capillary structure 22 is less than the thickness of each first capillary structure 21. Preferably, the thickness of the second capillary structure 22 is at least 2 times or 3 times less than the thickness of each first capillary structure 21. Thus, the thickness of the second capillary structure 22 is less than 1000 μm.The thickness of the second capillary structure 22 is preferably between 10 μm and a few hundred μm, for example between 10 μm. pm and 400 pm. The second material may be a paper-like material, for example blotting paper or a non-woven or woven material. It is thin enough to allow cooling of the plate due to the evaporation of the water soaking the second capillary structure. However, it is thick enough to allow sufficient capillary pumping.

[0054] The dimension of the second capillary structure 22, along the lateral axis Y, is greater than that of the first capillary structure. The dimension of the second capillary structure, along the lateral axis Y, is for example greater than 2 times or even 3 times or 4 times the dimension of the first capillary structure along the lateral axis Y.

[0055] The capillary rise height of the second material, or more generally of the second capillary structure, is greater than the capillary rise height of the first material. The capillary rise height of the second material is preferably greater than 10 cm, or even greater than 20 cm or 30 cm.

[0056] Under the effect of capillary pumping, the water stored in each first capillary structure 21 migrates through the second capillary structure 22, along the wetted face. The migration of water through each second capillary structure 22 is shown by the arrows F2.

[0057] Thus, at the level of a wet channel, the migration of the liquid takes place: - along the longitudinal axis X, through each first capillary structure 21, from at least one longitudinal end 21x; - then from each first capillary structure 21, through the second capillary structure 22, along the wet face.

[0058] [Fig.3C] represents a section, along a YZ plane, of a wet channel 20w adjacent to a dry channel 20d. The wet faces 10w delimiting the wet channel 20w are coated with a second capillary structure 22 as previously described. Each second capillary structure 22 is in fluidic contact with a first capillary structure 21. Each second capillary structure 22 is applied in contact with a plate, so as to promote the cooling of the plate under the effect of evaporation.

[0059] The amount of water evaporating from each second capillary structure is compensated by the capillary pumping of the water stored in each first capillary structure. This makes it possible to maintain, along each wet face, a sufficient amount of water to allow evaporation in the wet channel. This results in cooling of the plate, allowing cooling of the air circulating in the adjacent dry channel, according to the operating principle described in connection with [Fig.l].

[0060] In the configuration shown in Figures 3A to 3C, each first capillary structure 21 forms a lateral border of a wet channel. This configuration is advantageous because under the effect of humidification, each first capillary structure ensures a seal of the wet channel, in a direction parallel to the longitudinal axis. This simplifies the manufacturing process, for example by avoiding the formation of a partition, closing the wet channel, along the longitudinal axis.

[0061] In [Fig.3D], another configuration is shown, according to which the first capillary structure 21 of a wet channel 20w extends parallel to the longitudinal axis, not at the level of the lateral edge of the channel, but at the center of the latter.

[0062] In [Fig. 4], the wet face is shown as described in connection with Figures 3A to 3C. The first two capillary structures 21 are distinguished, extending along the lateral edges 11, 12 of the plate, as well as a second capillary structure 22, extending between the first capillary structures, along the wet face.

[0063] At each dry channel, along each notch 17, the adjacent plates, delimiting the dry channel, join, forming a curved dry partition. Thus, a dry partition, closing a dry channel, extends between two wet outlets 20 WjOUt of two adjacent wet channels.

[0064] In the example shown, each first capillary structure is supplied by the two opposite longitudinal ends 21x. According to one possibility, each first capillary structure is supplied by a single longitudinal end 21xpu by one or more zones located along said first capillary structure.

[0065] Closure walls 18, called wet closure walls, are applied against the stack of plates 10, facing each wet outlet. Each wet closure wall 18 makes it possible to collect the wet air leaving different wet channels. Thus, each wet closure wall 18 makes it possible to form an evacuation chamber 20, making it possible to collect the wet air resulting from wet channels, and to transport the wet air, in a sealed manner, facing the dry partitions, the latter being formed at the level of each notch.

[0066] [Fig.5A] represents a stack 2 of plates 10, alternately delimiting dry channels and wet channels. The stack is housed in a frame 3, part of which is shown in [Fig.5A]. Longitudinal ends 21x of the first capillary structures 21 can be seen, at each lateral edge of the stack.

[0067] In [Fig.5B], a detail of the stack is shown. The first three plates 10i, 102, 103 of the stack have been identified. The rank n assigned to each plate is lower the higher the plate is when the transverse axis is vertical. The plate 10i corresponds to the upper plate of the stack. Each longitudinal end 21x of a first capillary structure is connected to a longitudinal end of an adjacent first capillary structure by a fluid connection. In the example shown, a permeable capillary connecting material 23 provides a fluid bridge between the different first capillary structures. As described below, a water inlet makes it possible to wet the first upper capillary structure, that is to say the first capillary structure formed at the wet channel delimited by the plates of the lowest rank (n = 1 and 2 when the first plates delimit a wet channel, or n = 2 and 3 when the first plates of rank 1 and 2 delimit a dry channel). The water migrates, by capillarity, along the first capillary structure 21, along the longitudinal axis. In addition, under the effect of gravity, the water migrates, step by step, between the successive first capillary structures, by means of the connecting material 23. Thus, the wetting of the first capillary structures is carried out: - along each first capillary structure 21, by capillarity, along the longitudinal axis X; - between two first successive capillary structures, extending into two adjacent wet channels, by the combined action of capillarity and gravity, along the transverse axis Z.

[0068] According to one possibility, the longitudinal ends 21x of two successive first capillary structures are in contact with each other. The longitudinal ends 21x then act as a connecting material.

[0069] The fact that the different first capillary structures 21 are in contact with each other, or by means of a capillary connecting material 23, makes it possible to maintain an identical hydraulic pressure, or one that can be considered as such, at each end 21x. The hydraulic pressure is, in this example, close to or equal to atmospheric pressure. This allows uniform humidification, or one that can be considered as such, of the first capillary structures 21, and this independently of the rank n. This makes it possible to ensure uniform wetting, or one that can be considered as such, of all the wetted faces of the stack. Thus, the wetting of each wet face can be considered as similar, and independent of the rank n. A wet face is wetted in the same way, whether it is close to the upper plate or close to the lower plate.

[0070] We understand the complementarity of each capillary structure: the first capillary structure essentially has a water reservoir function, to supply the second capillary structure with which it is in contact. The second capillary structure allows diffusion of water, by capillarity, along a wet face, and this in the most uniform way possible. Each first capillary structure also allows transfer of water between the different plates, by capillarity and gravity.

[0071] In [Fig.5C], the complete chassis 3 is shown. The chassis 3 defines water inlets 25, taking the form of a well, intended to be supplied with water. Each well 25 is in fluid contact with each first upper capillary structure. Each first upper capillary structure is wetted by water flowing from the well 25 arranged directly above said first capillary structure. The water migrates by capillarity along the first capillary structure, as well as, by capillarity and gravity, towards the adjacent first capillary structure. The migration of water towards the different first capillary structures is thus carried out by combining longitudinal diffusion and transverse diffusion.

[0072] The water inlet is connected to a water inlet, coming from outside the device. A portion of the water distributed at the water inlet may come from a receptacle 27 connected to a water outlet 26.

[0073] In [Fig.5D], a detail of the upper part of the stack shown in [Fig.5C] is shown. The upper wet channel is delimited by the plates 101 and 102. The well 25 is supplied with water, so as to wet the first capillary structure arranged between the plates 101 and 102, then, step by step, the first capillary structures arranged between the plates 103 and 104, then 105 and 106....

[0074] According to an alternative, several first capillary structures of the same stack are formed by the same part, formed of the first material, applied against a lateral edge 11, 12 of each plate. The part can be applied against the stack 2, so as to engage, under the effect of mechanical pressure applied parallel to the Y axis, in the wet channels. The part thus forms a lateral partition of different wet channels. The part can be monolithic. It can be applied against all the plates of the same stack.

[0075] [Fig.5E] shows the lower part of the stack. The water outlet 26 allows the flow of excess water flowing from the first lower capillary structure, i.e. the first lowest capillary structure. The excess water is collected in a receptacle. A pump 28 is configured to recover the water from the receptacle, so as to re-supply the water inlet 25. The water supply to the water inlet 25 comprises water coming from outside the device, as well as water collected in the receptacle. It is noted that the excess water, collected in the receptacle 27, has not undergone evaporation. It is therefore not concentrated in insoluble impurities, of the mineral type, present in the water. It can therefore be readmitted into the water inlet 25, without risk of fouling the device.

[0076] In [Fig.5F], a device is shown comprising four frames 3, each frame carrying a stack 2. Each frame 3 comprises a water outlet 26, as well as a fluid circuit making it possible to collect the water resulting from each water outlet in the receptacle 27. The pump 28 is arranged to supply each water inlet 25 from the water collected in the receptacle.

[0077] Due to its thickness, greater than the thickness of the second structures ca pillars 22 with which it is in contact, each first capillary structure 21 behaves as a buffer reservoir. Thus, part of the water intended for wetting the second capillary structures 22 is temporarily stored in the first capillary structures. This buffer storage function allows sequential supply of each water inlet 25.

[0078] The arrangement of the first capillary structures 21 and the second capillary structures 22 allows controlled wetting of each wetted face delimiting wet channels. The diffusion of water by capillarity, along the wetted faces, makes it possible to maintain sufficient wetting to allow effective cooling of the plates.

[0079] A continuous supply is not necessary, given the buffer storage exerted by each first capillary structure 21. The sequential supply can be determined based on calibration tests. The pumping of water from the receptacle can be carried out based on the water level in the latter.

[0080] [Fig.6] shows a view of the stack 2 facing the hot inlets 20djin of the dry channels 20d. The hot inlets 20djin are intended to receive the air to be cooled, the latter coming from the air intake of the device. At each hot inlet 20djin, the plates delimiting each dry channel are spaced apart from each other, so as to form an opening 15'. Between each opening 15', a dry partition is provided, along the notches 17, by contact between the plates delimiting the dry channel.

[0081] According to one possibility, the second capillary structure is formed by structuring each wetted face, for example by providing channels configured to allow capillary pumping.

[0082] According to one possibility, the first capillary material is identical to the second capillary material. However, it is preferable that the first capillary material is different from the second capillary material, and has a capillary rise height greater than the second capillary material, as previously described.

[0083] The previously described configuration allows controlled wetting of each wetted face delimiting wet channels. The water supply to the device can be sequential, thanks to the buffer storage function provided by the first capillary structures 21. The excess water is collected at the level of receptacles 27, and can be pumped to be directed towards the water inlet 25. As a result, the device does not have a water outlet. This facilitates its implementation, by minimizing installation constraints. This is particularly true in individual housing.

[0084] The diffusion of water by capillarity, along the wetted faces, makes it possible to maintain a sufficient quantity of water to allow effective cooling of the plates. The supply of each water inlet allows renewal of the circulating water in the device.

[0085] Although described in connection with water, the device can be implemented with another liquid.

Claims

Claims

1. An indirect evaporative cooling air conditioning device (1), 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 (2), the plates being spaced from each other along a transverse axis (Z), each plate comprising a dry face (10d) opposite a wet face (10w), the wet face 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; the device being such that, in each stack: - two adjacent plates delimit a channel, the channel being: • either a dry channel (20d), delimited by two dry faces (10d) of two adjacent plates, • either a wet channel (20w), delimited by two wet faces (10w) 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; - each dry channel (20d) extends, along a longitudinal axis (X), between an air inlet (20djin), connected to the air intake, and a cold outlet (20djOUt), the cold outlet being intended for evacuation of cooled air following the flow of air in the dry channel; - each wet channel (20w) extends along the longitudinal axis, between a wet inlet (20Wjin) and a wet outlet (20WjOUt), the wet outlet being intended for evacuation of humidified air following the flow in the wet channel, the wet channel being configured so as to receive a portion of the air emerging from the dry channel; the device being characterized in that: - each wet channel has a first structure ca- pillar (21), formed of a first capillary material, configured to be wetted by water, the first capillary structure being arranged in contact with at least one wetted face delimiting each wet channel; - at least one wetted face of each wet channel comprises a second capillary structure (22), the second capillary structure extending from the first capillary structure, along the wetted face, the second capillary structure being thinner than the first capillary structure; - the stack comprises a water inlet (25), configured to receive water, the water inlet being in fluid contact with at least one first capillary structure.

2. The device of claim 1, wherein the second capillary structure is formed from a second capillary material.

3. A device according to claim 2, wherein the second capillary material is a woven or non-woven fabric or a paper.

4. Device according to claim 2 or claim 3, in which the capillary rise height of the first capillary material is less than the capillary rise height of the second capillary material, the capillary rise height corresponding to a height reached, by capillary pumping, in the first or second material arranged vertically.

5. Device according to claim 1, in which the second capillary structure is formed by structuring each wetted face.

6. Device according to any one of the preceding claims, in which two first capillary structures, extending along two adjacent wet channels, are in contact with each other, so as to allow circulation of water from one first capillary structure to the other.

7. Device according to claim 6, wherein the contact between the first capillary structures is made by direct contact or by a capillary bonding material (23).

8. Device according to any one of the preceding claims, in which each wet channel is delimited by two lateral edges (11, 12), extending parallel to the longitudinal axis, each wet channel comprising a first capillary structure extending along at least one of the longitudinal edges. less a side border.

9. Device according to any one of the preceding claims, in which the first capillary structure of at least one wet channel extends, along the transverse axis (Z), with a thickness greater than 0.3 mm and / or less than 10 mm.

10. Device according to any one of the preceding claims, in which the second capillary structure covering the wetted faces of at least one wet channel extends, along the transverse axis, with a thickness of less than 1000 μm.

11. Device according to any one of the preceding claims in which: - each wet channel of the stack is assigned a rank, the rank increasing with the distance, along the transverse axis, from the water inlet; - the wet channel of rank 1 is adjacent to the water inlet; - two first successive capillary structures, arranged respectively in two wet channels of successive ranks are in fluid contact with each other.

12. Device according to claim 11, in which the fluid contact is effected by direct contact of the first two successive capillary structures or by an auxiliary material, extending between the first two capillary structures, so that when the transverse axis is vertical, water, admitted through the water inlet, flows by gravity and by capillarity between the first two successive capillary structures.

13. Device according to any one of claims 11 or 12, comprising: - a water outlet (26) configured to allow a flow of water flowing from the first capillary structure of maximum rank; - a receptacle (27), intended to receive the water flowing through the water outlet - a pump (28), configured to pump the water collected in the receptacle, so as to admit the water into the fluidic water inlet.

14. The device of claim 13, wherein the pump is configured to sequentially pump water collected in the receptacle.

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