An evaporative cooling panel for use in an evaporative cooling pad and air treatment unit, methods of manufacture

Abstract

An evaporative cooling pad (1) comprising evaporative cooling panels (2), each panel (2) comprising a sheet (3) having one or more first creases (4), said first creases dividing the sheet in two or more faces (6a, 6b) and giving the panel a three-dimensional configuration, said first creases (4) extending in a main direction (M) of the panel, such that the panel is compressible in a direction (C) transverse to the main direction. An air treatment unit (20) including two or more of the evaporative cooling panels.

Description

[0001] An evaporative cooling panel for use in an evaporative cooling pad and air treatment unit, methods of manufacture

[0002] Technical field

[0003] The present disclosure relates to an evaporative cooling panel adapted to be used in an evaporative cooling pad, a stack of evaporative cooling panels, an evaporative cooling pad comprising the stack of evaporative cooling panels, an air treatment unit including the evaporative cooling pad, and methods of manufacturing an evaporative cooling panel, a stack of evaporative cooling panels and for mounting the stack of evaporative cooling panels in an air treatment unit.

[0004] Background art

[0005] Air treatment units, such as evaporative air coolers and humidifiers, may be used to humidify and cool different types of spaces in buildings. An evaporative air treatment unit is a device that cools or humidifies air by evaporating a liquid cooling medium, typically water. It is an energy-efficient alternative to traditional air conditioning systems, which use refrigerant chemicals to cool the air. Evaporative air coolers are often used in areas where air conditioning is not practical or too expensive, such as in dry regions, outdoor spaces, or in areas with frequent power outages. They are also considered environmentally friendly as they consume less energy than conventional air conditioning units and do not use harmful chemicals. Evaporative air coolers and humidifiers typically comprise cooling pads in the form of stacks of corrugated evaporative cooling panels or sheets with flutes forming passageways through the pad. US5143658 discloses an example of typical prior art evaporative cooling pad.

[0006] There is an ongoing interest in improving pads for evaporative coolers and humidifiers to meet the continuously increasing demands on sustainability and cost reduction.

[0007] Summary of the invention

[0008] The present disclosure aims at providing an improved evaporative cooling panel a stack of evaporative cooling panels, an evaporative cooling pad comprises the stack of evaporative cooling panels, an air treatment unit including the evaporative cooling pad, and methods of manufacturing an evaporative cooling panel, a stack of evaporative cooling panels and for mounting the stack of evaporative cooling panels in an air treatment unit.

[0009] The basic principle behind evaporative air cooling is the process of evaporation of a liquid cooling medium, typically water. When water evaporates, it absorbs heat, and as a result, the surrounding air becomes cooler. An evaporative air treatment unit, or evaporative air cooler, uses this principle to cool the air by blowing it over a wet cooling pad or through a series of wet cooling pads. As the air passes over the wet pad, the water evaporates, which cools and humidifies the air. The cooled air can then be circulated into a space where cooling is desired. The temperature reduction provided by an evaporative air cooler depends on the dryness of the air, and the relative humidity of the environment. It is very effective for use in hot, dry climates, where the air is less humid. In more humid environments, the cooling effect may be less noticeable.

[0010] The cooling pad in an evaporative air cooler plays a critical role in the cooling process by providing a large surface area for the water to evaporate from and cooling the air as it passes through. The cooling pad is usually placed on the intake side of the cooler and is kept wet by a water pump or gravity feed system. Overall, the cooling pad used in air treatment is a critical component of an evaporative air cooler, and its performance can have a significant impact on the cooling efficiency of the device. In order to obtain effective cooling and humidification, it is desirable that the cooling pad is comprised of evaporative cooling panels having a corrugated surface, so as to increase the heat transfer between the air and the cooling liquid. When cooling pads are shipped from a manufacturer to an installation site, they are typically wrapped in protective material and loaded in containers. A large part of the container space is taken up by air due to the corrugated shape of the evaporative cooling panels.

[0011] It is an object of the present disclosure to provide an improved evaporative cooling pad, by means of which effective cooling and humidification of an air flow can be obtained and which can contribute to improved sustainability in the stages from manufacture to installation.

[0012] The present disclosure relates to an evaporative cooling pad comprising evaporative cooling panels, formed from sheets of evaporative cooling media material. Each panel comprises a sheet having one or more first creases, the first creases dividing the sheet in two or more faces and giving the panel a three-dimensional configuration, the first creases extending in a main direction of the panel, such that the panel is collapsible (compressible) and expandable in a direction transverse to the main direction. Thereby, the panel can be in a collapsed state (compressed stated) or in an expanded state. In the present context, the expressions "collapsible" and "compressible" relate to the feature of reducing the volume of the panel or stack of panels by folding the panel(s) down, e.g. when packing them away for shipping. The creases allow the panels to collapse (or be compressed) and expand, in an accordion-like or bellows-like manner, by pressing the sides of the panel to collapse / compress, and drawing the sides of the panel apart to expand into an expanded state. In the collapsed (or compressed) state, the creased sheets of the evaporative cooling panels take up very little space. Thereby, the panels can be collapsed / compressed and compacted before being packed for shipping to an installation site, thus decreasing the volume to be shipped and reducing cost and energy consumption related to shipping. A plurality of panels may suitably be arranged into a stack of evaporative cooling panels, which forms a semi-finished evaporative cooling pad. The panels may then be positioned with the surfaces facing each other, such the entire stack of panels is collapsible / compressible in a direction transverse to the main direction of the panels. When the cooling pad is to be installed in an air treatment unit, the panels of the stack of evaporative cooling panels can again be expanded to unfold and open up into an expanded state to form an evaporative cooling pad, wherein the two or more faces become available for evaporative cooling of an air flow. In the expanded state, the cooling pad thus has the full volume to provide optimal contact between the surfaces of the cooling panels and the cooling medium.

[0013] Further, the present disclosure relates to a method of manufacturing an evaporative cooling panel as described above, comprising providing evaporative cooling panel sheet material; and creating creases in the sheet material, including creating one or more first creases in the sheet material, dividing the sheet in two or more faces and giving the panel a three- dimensional configuration, the first creases extending in a main direction of the panel, such that the panel is compressible in a direction transverse to the main direction. The method may include creating one or more second creases in the sheet material, said second creases extending at an angle between adjacent first creases, and the creases may be created by folding of the sheet material, wherein the steps of creating first creases and second creases by folding are performed alternatingly, until a desired number of crease have been formed in the panel. Various ways of obtaining cooling panels can be contemplated. In its simplest form, only one crease may be present in the main direction of the sheet, typically in the length direction. Preferably, said first creases in the sheet forming the evaporative cooling panel comprise ridge creases and valley creases, giving the cooling pad at least four faces, to further improve cooling. Thus, by including multiple ridge and valley creases running in the main direction of the panel, a larger evaporative cooling surface can be comprised in each panel.

[0014] A ridge crease is a fold that is created by folding the sheet in such a way that the resulting fold line forms a raised ridge or "mountain." Ridge creases may also be referred to as mountain creases. When a ridge crease is folded, the folded portion of the sheet will be on the outside of the model, creating a raised surface. A valley crease is a fold that is created by folding the sheet in such a way that the resulting fold line forms a valley or indentation. When a valley crease is folded, the folded portion of the sheet will be on the inside of the model, creating a concave surface. Ridge creases, together with and valley creases, define the three-dimensional structure of a folded sheet. By combining valley and mountain creases in various ways, intricate and detailed designs can be achieved.

[0015] The valley and mountain creases formed in the sheet give the resulting evaporative cooling panel a jagged or craggy configuration so that when two or more panels are placed together, channels are formed between the panels, which act as air through flow channels during operation of the cooling pad.

[0016] An example of folding including ridge creases and valley creases is the accordion fold, also known as the concertina fold, which is a folding technique that involves folding a sheet back and forth in a zigzag pattern. An accordion fold can be obtained by folding and creasing the sheet lengthwise, aligning the short edges together, to create a desired number of creases running in the length direction of the sheet. Each fold should preferably be made parallel to the previous one. By creating the alternating folds, a pleated or zigzag pattern is obtained, which resembles an accordion, with alternating valley and ridge creases. The bellows or accordion fold allows for easy expansion and compression. By pushing the folded sections together, the panel can be collapsed / compressed, reducing the overall size, and conversely, by pulling the folded sections apart, the panel can be expanded, stretching it out to reveal the entire surface, similar to how an accordion instrument expands and contracts.

[0017] In the sheet forming the evaporative cooling panel, each of said first creases running in the main direction of the panel may preferably be comprised of alternating ridge creases and valley creases, and may advantageously further be combined with a number of second creases, said second creases extending at an angle between adjacent first creases and being alternating ridge creases and valley creases. This gives an improved three-dimensional structure to the sheet, with several faces directed in different directions, which enhances the contact between air and water in the cooling pad and thus further improves the evaporative cooling.

[0018] An example of folding technique that includes both first alternating ridge and valley creases, and second ridge and valley creases extending at an angle between adjacent first creases is herringbone origami, which may also be referred to as "herringbone tessellation" or simply "herringbone fold." The term "tessellation" refers to a repeating pattern of folded units that fit together without gaps or overlaps, similar to how tiles tessellate in a pattern. The name "herringbone" is derived from the resemblance of the folded pattern to the bones of a herring fish. When the panel is collapsed / compressed, the faces of the sheet are brought together so that the panel becomes a dense multi-layer structure.

[0019] Another example of folding including first creases comprising ridge creases and valley creases, and second creases extending at an angle between adjacent first creases and being alternating ridge creases and valley creases, may be the Miura-ori folding, described in e.g. JP2018203532A, which consists of a series of parallel creases in a zigzag pattern. When the sheet is folded along these creases, it can be collapsed / compressed into a compact, flat shape. Conversely, by pulling apart the opposite edges, the folded sheet can be easily expanded into a larger surface.

[0020] Sheets folded by means of the above mentioned herringbone or Miura-ori techniques have an excellent ability to maintain their shape and structural integrity throughout the folding and unfolding process, i.e. compression and expansion, and offers a sufficient balance between rigidity and flexibility, making it useful for folding sheets that require both stability and easy manipulation, as is desired in the collapsible / compressible evaporative cooling pads of the present invention.

[0021] As an alternative to folding, the creases can also be obtained by embossing the sheet between embossing die plates or rollers having a surface pattern corresponding to the desired configuration of the evaporative cooling panel. The embossing can for example be performed in an embossing apparatus, which is somewhat similar to a corrugator. The embossing die can be in the form of a die plate or a die roller having a desired surface pattern that will be transferred onto the sheet material. In order to effectively obtain a desired three-dimensional configuration in the resulting cooling panel, the sheet may be formed between a pair of die plates or rollers that have matching surface patterns. The die plates or roller may typically be made of metal. The sheet material to be embossed is positioned on the feed area of the apparatus and pressure is applied to the material through the embossing die(s) or plate(s). The pressure forces the sheet material into the cavities or recesses of the embossing die, creating the raised or recessed shape of the sheet material. Heat may be applied along with pressure during the embossing process, especially when the sheet material benefit of thermal deformation, such as plastic materials. Once the embossing process is complete, the pressure is released, and the material is allowed to cool and solidify. Cooling ensures that the embossed pattern retains its shape and definition. The embossed sheet can then be removed from the machine, and used as an evaporative cooling panel in a cooling pad. An embossing process can be performed either by forming the panels sheet by sheet, or by feeding sheet material from a supply roll in a continuous manner, and cutting the embossed sheet material into evaporative cooling panels after embossing.

[0022] The evaporative cooling pad may suitably comprise a plurality of evaporative cooling panels arranged in alternating position such that channels are formed between the panels, to improve mass and heat transfer. Thus, a stack of evaporative cooling panels is provided according to the present invention, which stack of panels comprises a plurality of evaporative cooling panels as described herein. The number of panels included in a cooling pad can vary depending on the intended use of the pad. In general, cooling pads can range from a few sheets to multiple layers of panels depending on the desired level of cooling efficiency. The number of panels used in the cooling pad can range for example from 4 to 12, depending on factors such as the size of the pad, the type of cooling medium used, and the required cooling capacity.

[0023] The sheets forming the evaporative cooling panels are advantageously comprised of foldable and water resistant sheet material, preferably resin impregnated paper, cellulose based materials, fiberglass sheet, metal foil or plastic sheet material.

[0024] Resin impregnated paper, for example resin-impregnated kraft paper or resin- impregnated cellulose, is a composite material consisting of paper that has been saturated or impregnated with a synthetic resin, for example phenolic resin or melamine resin, to provide added strength, durability, and other desirable properties to the paper. The resin impregnation process enhances the mechanical strength and dimensional stability of the paper, making it more resistant to tearing, punctures, and deformation, while still allowing it to be molded, shaped, or formed into various complex shapes and sizes, providing flexibility in design and manufacturing. Cellulose based materials may be made from cellulose fibers or a mixture of cellulose fibers and synthetic fibers, and are cost-effective and highly absorbent and can hold a large amount of water, which makes them effective at cooling air.

[0025] Fiberglass sheet material is a composite material composed of fine glass fibers embedded in a resin matrix, such as polyester, epoxy, or vinyl ester. Plastic sheet material may be made from polypropylene (PP), high-density polyethylene (HDPE), or polycarbonate (PC), which are lightweight durable materials that are relatively inexpensive. Metal foil, or metallic sheet material, may be made from aluminum, copper, or stainless steel.

[0026] The sheets are suitably designed to retain water and allow air to flow through them, which creates a cooling effect as the water evaporates.

[0027] The sheet material may preferably be hydrophilic to improve wetting and spreading properties and may be comprised of hydrophilic material, such as cellulose based materials or cotton based materials, or the sheet material may be surface treated with a hydrophilic surfactant. Examples of surfactants that can increase hydrophilicity of the sheet material are nonionic surfactants, such as ethoxylated alcohols; anionic surfactants, such as sodium dodecyl sulfate (SDS); water-soluble polymers, such as polyethylene glycol (PEG); or cationic surfactants, such as cetyltrimethylammonium bromide (CTAB) or poly(diallyldimethyl-ammonium chloride) (PDADMAC).

[0028] The sheets forming the evaporative cooling panels are advantageously perforated by a plurality of through openings. The openings facilitate water distribution over the evaporative cooling panel and improves air flow through the sheets , increasing heat transfer and reduced pressure drop.

[0029] The present disclosure also relates to a method of manufacturing a stack of evaporative cooling panels, comprising the steps of providing a plurality of evaporative cooling panels as described above; arranging the panels in alternating positions such that channels are formed between the panels; and attaching each of the panels to an adjacent panel. The evaporative cooling panels forming the stack of evaporative cooling panels are suitably attached to each other at the edges of the sheets. Thereby the panels can move slightly in relation to each other and part a little during operation, which reduces pressure drop. Suitable means of attaching the evaporative cooling panels to each other are adhesive, preferably polyurethane, silica, PVA, or starch glue; mechanically, preferably by needles, staples of semi-punching, or spot welding. Adhesive joining may be obtained by application of for example hotmelt adhesive that is applied in a molten state and solidifies as it cools, or contact adhesive that is applied to both surfaces and allowed to dry before the two surfaces are pressed together. Spot welding can be accomplished using ultrasonic welding.

[0030] The present disclosure also relates to an air treatment unit, comprising an evaporative cooling pad as described above, a frame adapted to receive the cooling pad, the frame having an air inlet and an air outlet, and an inlet for liquid cooling medium and an outlet for liquid cooling medium. The frame suitably includes attachment devices, such as hooks, to hold the cooling pad. The air treatment unit may further comprise a liquid distributor arranged above the cooling pad and adapted to distribute liquid cooling medium, typically water, over the surfaces of the evaporative cooling sheets, and a fan adapted to draw air through the stack of evaporative cooling panels from the air inlet to the air outlet. The air treatment unit may further comprise a liquid receiving container arranged below the cooling pad, and being adapted to receive liquid cooling medium. A liquid conduit connecting the fluid receiving container with the fluid distributor and a pump adapted to pump liquid cooling medium from the fluid receiving container to the fluid distributor, may also be included in the air treatment unit.

[0031] The present invention will become apparent from the description of embodiments. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

[0032] However, it is to be noted that while the present disclosure is mainly related to cooling and humidifying of air, the pad of the present invention could as well be used in other applications where heat and mass transfer based on evaporation is involved, for example in chemical engineering processes. Hence, in such applications, the terms "cooling" and "humidification" as used in the context of the present disclosure may then be replaced by, or referred to as "heat transfer" and "mass transfer", respectively. Accordingly, in such applications the component herein referred to as a "cooling pad", may then rather be referred to as a "heat transfer pad" or a "mass transfer pad", etc.

[0033] Hence, it is to be understood that the herein disclosed cooling pad and air treatment unit are not limited to the particular component parts of the device described since such device may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting.

[0034] Brief of the

[0035] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and nonlimiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

[0036] Figure 1 is a perspective view of an example of an evaporative cooling panel for an evaporative cooling pad according to the present disclosure;

[0037] Figure 2 shows another example of an evaporative cooling panel for an evaporative cooling pad according to the present disclosure;

[0038] Figure 3 shows schematically how a herringbone pattern is distributed over a sheet for an evaporative cooling panel according to the present disclosure;

[0039] Figure 4 is a schematic perspective view of an evaporative cooling pad comprising a plurality of evaporative cooling panels according to the present disclosure; Figure 5 is a schematic top view of an evaporative cooling pad comprising a plurality of evaporative cooling panels according to the present disclosure;

[0040] Figures 6A and 6B illustrate schematically a portion of an evaporative cooling panel in expanded and collapsed state, respectively;

[0041] Figures 7A-H illustrate schematically an example of how a herringbone folding can be made to form an evaporative cooling pad from a sheet according to the present disclosure;

[0042] Figure 8A is a schematic cross-sectional view of an air treatment unit in which the cooling pad according to an embodiment of the present disclosure can be included;

[0043] Figure 8B is a schematic front view of the air treatment unit in Fig. 8A.

[0044] Figure 9 illustrates schematically an embossing apparatus for forming evaporative cooling media sheet material into evaporative cooling panels.

[0045] Figures 10a and 10b illustrate schematically methods of manufacturing an evaporative cooling panel.

[0046] Figure 11 illustrates schematically a method of manufacturing a stack of evaporative cooling panels.

[0047] Figure 12 illustrates schematically a method of mounting the stack of evaporative cooling panels in an air treatment unit.

[0048] Detailed description of example embodiments

[0049] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in otherforms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

[0050] Figure 1 shows schematically an example of an evaporative cooling panel for an evaporative cooling pad according to the present disclosure. The panel 2 is formed from a sheet 3. The sheet 3 is perforated by a plurality of through openings 10. A plurality of first creases 4 divide the sheet in a plurality of faces 6a, 6b, such that the sheet has a three-dimensional configuration. The arrows illustrate the direction of compression. Figure 1 illustrated how the first creases 4 can be ridge creases 4' and valley creases 4".

[0051] Figure 2 shows another example of an evaporative cooling panel for an evaporative cooling pad according to the present disclosure. In this example, the sheet 3 forming the panel has a herringbone origami folding giving the panel a three-dimensional configuration. The first creases 4 divide the sheet in a plurality of faces 6a, 6b, and extend in a main direction M of the panel, such that the panel is collapsible / compressible in a direction C transverse to the main direction, which is illustrated by the arrows in Fig. 2. In the example of Figure 2, each of the first creases 4 are comprised of alternating ridge creases 4a and valley creases 4b, and second creases 5a, 5b extending at an angle between adjacent first creases are provided as alternating ridge creases 5a and valley creases 5b. The sheet may be perforated by through openings (not shown).

[0052] Figure 3 shows schematically how a herringbone pattern is distributed over a sheet 3 for an evaporative cooling panel according to the present disclosure. Here, valley creases 4b, 5b are represented by dashed lines, and ridge creases 4a, 5a are represented by solid lines.

[0053] Figure 4 shows an evaporative cooling pad comprising a plurality of evaporative cooling panels. In this example, 12 panels are included in the cooling pad. The evaporative cooling panels 2 are arranged in alternating position such that channels 9 are formed between the panels. The sheets are perforated by a plurality of through openings 10. Figure 4 also shows the air and water direction during operation of the cooling pad, as well as the direction of compression / expansion.

[0054] Figure 5 is a top view of an evaporative cooling pad comprising 6 panels 2, where the panels have a herringbone origami configuration. The panels may be perforated by through openings (not shown). As shown in Fig. 5, the evaporative cooling panels 2 can be attached to each other at the edges 11 of the sheets, for example by means of adhesive, preferably polyurethane, silica, PVA, or starch glue, mechanically, preferably by needles, staples of semipunching.

[0055] Figure 6A shows schematically a portion of an evaporative cooling panel in expanded state, and Figure 6B shows the same portion of the evaporative cooling panel when it has been compressed. As shown the creases and the faces have come much closer to each other in the collapsed / compressed state, so that the panel takes up less space. Figures 6A and 6b also indicate the air and water directions during operation of the cooling pad, as well as the direction of compression.

[0056] Figures 7A-H illustrate schematically an example of how a herringbone folding of a sheet of evaporative cooling media material can be made in order to form an evaporative cooling panel according to the present disclosure;

[0057] 1. Start from a sheet 3 of evaporative cooling media sheet material. Fold an edge 101a of the sheet up to the opposite edge 101b, aligning them perfectly. Crease and unfold. This initial fold creates a central crease 102as a reference line. Now, fold the edges 101a, 101b of the sheet to meet the central crease 102, ensuring that the edges align precisely with the central crease and make a sharp crease. The sheet now has first ridge creases 4' and valley creases 4", as shown in Figure 7A.

[0058] 2. Rotate the sheet 90 degrees counter-clockwise so that the central crease 102 is upwards, and fold and crease the left corner 103 of the sheet inward, aligning it with the central crease 102 as shown in Fig. 7B, to form an inclined second crease 104a. The edge 105 of the fold should be parallel to the bottom edge 106 of the sheet. The creases 104 thus obtained are at an angle in relation to the first creases obtained in step 1.

[0059] 3. Unfold the sheet and place it with the central crease 102 as valley crease and form a top row 107a of creases in "V"-configuration, resembling triangles, by pushing the top part of the adjacent ridge creases 108 to the back as shown in Fig. 7C, so that it becomes a valley crease 109.

[0060] 4. Compress the sheet (as shown in Figure 7D) and fold and crease again to make a next inclined second crease 104b as shown in Figure 7E.

[0061] 5. Unfold and push the portion 109b of the first creases that is between the new inclined second creases 104b (from step 4) and the previously formed second creases 104a (from step 2) in an opposite direction compared to the pushed portion 109a from step 3 (Figure 7F), to form a new row 107b of creases in "V"-configuration, which should look as shown in Figure 7G, when seen from the opposite side.

[0062] 6. Repeat steps 4 and 5 until the sheet has the crease pattern over the entire surface (Figure 7H) .

[0063] Figures 8A and 8B shows an example of an air treatment unit 20, comprising an evaporative cooling pad as described above. The air treatment unit 20 also includes a frame 30 adapted to receive the cooling pad 1, the frame having an air inlet 31 and an air outlet 32. The air treatment unit also includes (not shown) an inlet for liquid cooling medium and an outlet for liquid cooling medium. The frame may include attachment devices (not shown), such as hooks, to hold the cooling pad in an expanded state. A liquid distributor 26 is arranged above the cooling pad 1 and is adapted to distribute liquid 24 over the surfaces of the evaporative cooling pad, and a fan 25 is arranged to draw air 29 through the evaporative cooling pad from the air inlet 31 to the air outlet 32. A liquid receiving container 28 arranged below the cooling pad 1, and a liquid conduit connects the liquid receiving container 28 with the liquid distributor 26. A pump 22 is arranged to pump liquid from the liquid receiving container 28 to the liquid distributor 26.

[0064] Figure 9 schematically illustrates an example of a production line 44 an embossing apparatus that may be used to form sheet material 3 into evaporative cooling panels 2 for an evaporative cooling pad. In the shown example, the sheet material is supplied in a roll 48, but it could as well be supplied sheet by sheet. The embossing die roller 42 contains the desired pattern that will be transferred to the sheet material 3. If desired, the production line 44 may comprise an unwind station 50 for the sheet material roll 48 and an impregnation station 52 arranged before the embossing apparatus 54. The embossing roller 42 of the embossing apparatus 54 may be configured to feed a sheet material track 46 from the roll 48. The sheet material 3 is fed to the feed area of the embossing apparatus and pressure is applied to the material through the embossing die roller 42. The pressure forces the sheet material into the cavities or recesses of the embossing die roller, creating the raised or recessed shape of the sheet material, resulting in the desired three dimensional pattern. Heat may be applied along with pressure during the embossing process. Once the embossing process is complete, the pressure is released, and the material is allowed to cool, dry and solidify. The embossed sheet can then be forwarded to a cutting and stacking station 58, and be used as evaporative cooling panels in a cooling pad. An assembling station 60 can be arranged for attaching the cooling panels to each other by for example welding, sewing or gluing. The assembling station 60 may comprise a robot 62 for performing the attachment operation.

[0065] Figures 10a and 10b illustrate schematically methods 100 of manufacturing an evaporative cooling panel 2 comprising providing 101 evaporative cooling panel sheet material; and creating 102 creases in the sheet material, including creating 103 one or more first creases 4, 4a, 4b in the sheet material, dividing the sheet in two or more faces 6a, 6b and giving the panel a three-dimensional configuration, the first creases extending in a main direction M of the panel, such that the panel is collapsible / compressible in a direction C transverse to the main direction, as shown in Fig. 2. In step 104, one or more second creases 5a, 5b are creating in the sheet material, which second creases extend at an angle between adjacent first creases.

[0066] In the embodiment shown in Figure 10a, the steps 102 of creating the creases include folding of the sheet material, wherein the steps of creating first creases 103 and second creases 104 by folding are performed alternatingly.

[0067] In the alternative embodiment shown in Figure 10b, the step 102 of creating the creases includes a step 105 of embossing the sheet material between embossing die plates or rollers, so as to form the creases.

[0068] Figure 11 illustrates schematically a method of manufacturing a stack of evaporative cooling panels, comprising the steps of providing 201 a plurality of evaporative cooling panels 2; arranging 202 the panels in alternating positions such that channels are formed between the panels; and attaching 203 of the panels 2 to an adjacent panel, wherein the evaporative cooling panels 2 are suitably attached to each other at the edges of the sheets. The method may further comprise a step 204 of compressing the stack of evaporative cooling panels in a direction C transverse to the main direction of the panels, to collapse the stack.

[0069] Figure 12 illustrates schematically a method of mounting the stack of evaporative cooling panels in an air treatment unit comprising the steps of: providing 301 a stack of evaporative cooling panels as described above in a collapsed / compressed state; expanding 302 the stack of cooling panels into an evaporative cooling pad by pulling the sides of the panels in a direction C transverse to the main direction of the panels (see Fig. 2), such that the stack of cooling panels is in an expanded state; attaching 303 the outermost panels to a cooling pad receiving frame 30 adapted to receive the cooling pad 1. The method step of Fig 12 is preferably performed after transportation to an assembly site or to an end customer, where the stack of cooling panels is expanded and mounted in a frame. Hereby, it is possible to transport stacks of panels for use as cooling pads, which have a lower volume than what is the case for previously available prior art cooling pads.

Claims

CLAIMS1. An evaporative cooling panel (2) adapted to be used in an evaporative cooling pad (1), characterized in that said evaporative cooling panel (2) comprises a sheet (3) having one or more first creases (4), said first creases dividing the sheet in two or more faces (6a, 6b) and giving the panel a three-dimensional configuration, said first creases (4) extending in a main direction (M) of the panel, such that the panel is collapsible in a direction (C) transverse to the main direction.

2. The evaporative cooling panel of claim 1, wherein said first creases (4) comprise ridge creases and valley creases.

3. The evaporative cooling panel of claim 2, wherein each of said first creases (4) is comprised of alternating ridge creases (4a) and valley creases (4b) and that the sheet further comprises second creases (5a, 5b), said second creases extending at an angle between adjacent first creases and being alternating ridge creases (5a) and valley creases (5b).

4. The evaporative cooling panel of any one of claims 1-3, wherein the sheet is comprised of a foldable and water resistant sheet material, preferably resin impregnated paper, fiberglass sheet, metal foil or plastic sheet material.

5. The evaporative cooling panel of any one of claims 1-4, wherein the sheet (3) is perforated by a plurality of through openings (10).

6. A stack (1) of evaporative cooling panels (2), characterized in that it comprises a plurality of evaporative cooling panels (2) according to any one of claims 1-5, said evaporative cooling panels (2) being arranged in alternating position such that channels are formed between the panels.

7. The stack of evaporative cooling panels of claim 6, wherein the evaporative cooling panels (2) are attached to each other at the edges of the sheets.

8. The stack of evaporative cooling panels of claim 6 or 7, wherein the evaporative cooling panels (2) are attached to each other by means of adhesive, preferably polyurethane, silica, PVA, or starch glue, mechanically, preferably by needles, staples of semi-punching.

9. The stack of evaporative cooling panels of any one of claims 6 - 8, wherein the evaporative cooling panels (2) have been transversely compressed so that they are in a collapsed state.

10. An evaporative cooling pad (1) characterized in that it comprises a stack of evaporative cooling panels of any one of claims 6 - 9, said stack of evaporative cooling panels being in an expanded state.

11. An air treatment unit (20), comprising an evaporative cooling pad (1) according to claim 10 and a frame (30) adapted to receive the cooling pad (1), said frame having an air inlet (31) and an air outlet (32), and an inlet for liquid cooling medium and an outlet for liquid cooling medium.

12. The air treatment unit of claim 11, further comprising a liquid distributor (26) arranged above the cooling pad (1) and adapted to distribute liquid cooling medium (24) over the surfaces of the evaporative cooling sheets and a fan (25) adapted to draw air (29) through the stack of evaporative cooling panels (3) from the air inlet (31) to the air outlet (32).

13. The air treatment unit of claim 12, further comprising a liquid receiving container (28) arranged below the cooling pad (1), and being adapted to receive liquid cooling medium.

14. The air treatment unit of claim 13, further comprising a liquid conduit connecting the fluid receiving container (28) with the fluid distributor (26) and a pump (22) adapted to pump liquid cooling medium from the fluid receiving container (28) to the fluid distributor (26).

15. The air treatment unit of any one of claims 11-14, wherein the liquid cooling medium is water.

16. A method (100) of manufacturing an evaporative cooling panel (2) according to any one of claims 1-5, comprising- providing (101) evaporative cooling panel sheet material; and- creating (102) creases in the sheet material, including creating (103) one or more first creases (4, 4a, 4b) in the sheet material, dividing the sheet in two or more faces (6a, 6b) and giving the panel a three-dimensional configuration, said first creases extending in a main direction (M) of the panel, such that the panel is compressible in a direction (C) transverse to the main direction.

17. The method of claim 16, including creating (104) one or more second creases (5a, 5b) in the sheet material, said second creases extending at an angle between adjacent first creases.

18. The method of claim 16 or 17, wherein the step(s) (102) of creating the creases includes folding of the sheet material, wherein the steps of creating first creases (103) and second creases (104) by folding are performed alternatingly.

19. The method of claim 16 or 17, wherein the step (102) of creating the creases includes embossing (105) the sheet material between embossing die plates or rollers.

20. A method (200) of manufacturing a stack of evaporative cooling panels according to any one of claims 6-9, comprising the steps of providing (201) a plurality of evaporative cooling panels (2) according to claims- arranging (202) the panels in alternating position such that channels are formed between the panels; and- attaching (203) the panels (2) to an adjacent panel.

21. The method of claim 20, comprising the step (203) of attaching the evaporative cooling panels (2) includes attaching the panels to each other at the edges of the sheets.

22. The method of claim 20 or 21, comprising the step (204) of compressing the stack of evaporative cooling panels in a direction (C) transverse to the main direction of the panels.

23. A method (300) of mounting the stack (1) of evaporative cooling panels (2) of any one of claims 6-9 in an air treatment unit (20) comprising the steps of: - providing (301) a stack of evaporative cooling panels (2) of any one of claims 6-9 in a compressed state;- expanding (302) the stack of cooling panels into an evaporative cooling pad by pulling the sides of the panels in a direction (C) transverse to the main direction of the panels, such that the stack of cooling panels is in an expanded state; - attaching (303) the outermost panels to a cooling pad receiving frame (30) adapted to receive the cooling pad (1); wherein the method (300) is preferably performed after transportation to an assembly site.

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