AIR CONDITIONER AND HEAT EXCHANGER

Abstract

An air conditioner includes a heat exchanger including a first sheet that separates a first heat-exchange channel and a second heat-exchange channel, and a container configured to store water to be supplied to the first heat-exchange channel. The first sheet has a first surface defining the first heat-exchange channel. The first surface includes a reference surface, a first protrusion, and a second protrusion adjacent to the first protrusion The first protrusion and the second protrusion protrude relative to the reference surface in a thickness direction of the first sheet. The reference surface has a groove portion and a non-groove portion. The groove portion is defined between the first protrusion and the second protrusion. The groove portion is contiguous with the non-groove portion.

Claims

1. An air conditioner comprising: a heat exchanger including a first sheet that separates a first heat-exchange channel and a second heat-exchange channel; and a container configured to store water to be supplied to the first heat-exchange channel, wherein the first sheet has a first surface defining the first heat-exchange channel, the first surface including: a reference surface; a first protrusion; and a second protrusion adjacent to the first protrusion, wherein the first protrusion and the second protrusion protrude relative to the reference surface in a thickness direction of the first sheet, and wherein the reference surface has a groove portion and a non-groove portion, the groove portion is defined between the first protrusion and the second protrusion, and the groove portion is contiguous with the non-groove portion.

2. The air conditioner according to claim 1, wherein the reference surface is a flat surface, and wherein each of the first protrusion and the second protrusion has a first length in a longitudinal direction and a second length in a lateral direction orthogonal to the longitudinal direction, and the first length is longer than the second length in a virtual plane parallel to the reference surface.

3. The air conditioner according to claim 2, wherein the longitudinal direction intersects a first direction that extends from an inlet toward an outlet of the first heat-exchange channel.

4. The air conditioner according to claim 1, wherein the heat exchanger further includes a second sheet having a first surface, wherein the first surface of the second sheet faces and is spaced from the first surface of the first sheet in the thickness direction, and the first surface of the second sheet includes a reference surface, and wherein the first heat-exchange channel is defined by: the first surface of the first sheet; the first surface of the second sheet; and a pair of spacers located between the first sheet and the second sheet.

5. The air conditioner according to claim 4, wherein the first protrusion and the second protrusion are located at respective positions to face the reference surface of the second sheet in the thickness direction.

6. The air conditioner according to claim 2, wherein in each of the first protrusion and the second protrusion, at least one of the first length or the second length decreases as each of the first protrusion and the second protrusion protrudes farther from the reference surface.

7. The air conditioner according to claim 2, wherein one of the first length and the second length of the second protrusion is longer than that of the first protrusion.

8. The air conditioner according to claim 2, wherein each of the first protrusion and the second protrusion has the second length in the lateral direction of not less than 0.1 mm and not more than 1 mm, and wherein an interval between the first protrusion and the second protrusion is not less than 0.1 mm and not more than 1.0 mm.

9. The air conditioner according to claim 1, further comprising a water absorber in the first heat-exchange channel, wherein at least one of the first protrusion or the second protrusion is in contact with the water absorber.

10. The air conditioner according to claim 1, wherein the first sheet defines the second heat-exchange channel, and further includes a second surface opposite to the first surface, and wherein the second surface has a first recess that is recessed relative to the second heat-exchange channel.

11. The air conditioner according to claim 10, wherein the second surface of the first sheet further has a second recess, and wherein the first recess is aligned with the first protrusion and the second recess is aligned with the second protrusion.

12. The air conditioner according to claim 1, wherein the heat exchanger further includes a second sheet that faces and is spaced from the first surface of the first sheet in the thickness direction, wherein the second sheet has a first surface, and the first surface of the second sheet includes a reference surface, wherein the first heat-exchange channel is defined by: the first surface of the first sheet; the second sheet; and a first spacer and a second spacer, both being located between the first sheet and the second sheet and extending along a first direction that extends from an inlet toward an outlet of the first heat-exchange channel, wherein at least one of the first spacer or the second spacer is a first protruding wall, and wherein the first protruding wall is integral with the first sheet, protrudes relative to the first protrusion and the second protrusion from the reference surface of the first sheet in the thickness direction, and is in contact with the second sheet.

13. The air conditioner according to claim 12, wherein the heat exchanger further includes a third sheet that faces and is spaced from the first surface of the second sheet in the thickness direction, the third sheet including a reference surface, wherein the second heat-exchange channel is defined by: the first surface of the second sheet; the third sheet; and a third spacer and a fourth spacer, both being located between the second sheet and the third sheet and extending along a second direction that extends from an inlet toward an outlet of the second heat-exchange channel, the second direction intersecting the first direction, and wherein at least one of the third spacer or the fourth spacer is a second protruding wall, and wherein the second protruding wall is integral with the second sheet, protrudes relative to the first protrusion and the second protrusion from the reference surface of the second sheet in the thickness direction, and is in contact with the third sheet.

14. The air conditioner according to claim 13, wherein the second sheet and the third sheet are identical to the first sheet.

15. The air conditioner according to claim 14, wherein the reference surface of the first sheet, the reference surface of the second sheet, and the reference surface of the third sheet are flat surfaces, wherein each of the first sheet, the second sheet, and the third sheet has a square shape with cutouts at its corners in a virtual plane parallel to the respective reference surfaces, wherein the heat exchanger includes a first separator, a second separator, a third separator, and a fourth separator that each separate the first heat-exchange channel and the second heat-exchange channel from each other, and wherein the first separator, the second separator, the third separator, and the fourth separator are located at respective corners, each of the first separator, the second separator, the third separator, and the fourth separator is in contact with a corresponding end of the first protruding wall, a corresponding end of the second protruding wall, and the third sheet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a perspective view of an air conditioner.

[0007] FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 as viewed in a direction of an arrow.

[0008] FIG. 3 is a perspective view of a heat exchanger.

[0009] FIG. 4A is a rear view of a module for the heat exchanger.

[0010] FIG. 4B is a plan view of the module for the heat exchanger.

[0011] FIG. 4C is a right view of the module for the heat exchanger.

[0012] FIG. 5A is a front view of a module for a heat exchanger according to a first aspect.

[0013] FIG. 5B is a cross-sectional view taken along line 5B-5B of FIG. 5A as viewed in a direction of arrows.

[0014] FIG. 6A is a front view of a module for a heat exchanger according to a second aspect.

[0015] FIG. 6B is a cross-sectional view taken along line 6B-6B of FIG. 6A as viewed in a direction of arrows.

[0016] FIG. 7A is a front view of a sheet and water absorbers for a heat exchanger according to a third aspect.

[0017] FIG. 7B is a right view of the sheet and the water absorbers.

[0018] FIG. 8A is a front view of a sheet for a heat exchanger according to a fourth aspect.

[0019] FIG. 8B is a cross-sectional view taken along line 8B-8B of FIG. 8A as viewed in a direction of arrows.

[0020] FIG. 9A is a front view of a module for a heat exchanger according to a fifth aspect.

[0021] FIG. 9B is a right view of the module for the heat exchanger.

[0022] FIG. 9C is a bottom view of the module for the heat exchanger.

DESCRIPTION

[0023] An illustrative embodiment of the disclosure will be described. In FIG. 1, directional terms, left, right, front, rear, up, and down defined by arrows based on an air conditioner 1 placed in a normal usage orientation are used.

[0024] The air conditioner 1 illustrated in FIG. 1 may be, for example, an evaporative cooling type air conditioner that is installed on a floor of a space to be air-conditioned of, such as a factory. As illustrated in FIGS. 1 and 2, the air conditioner 1 includes a housing 14, a dust collection filter 20, a cooling unit 10, a tank unit 7, a water supply unit 15, a first fan 61, a second fan 62, a fan motor 6, and a partition plate 63.

[0025] The housing 14 has a rectangular parallelepiped shape elongated in an up-down direction. The housing 14 has an upper wall, a lower wall, a front wall, a rear wall, a left wall, and a right wall. The housing 14 may be made of resin or metal. The housing 14 is provided with wheels 141 at four corners of its lower wall. The housing 14 has an air inlet 3 at its left wall. The air inlet 3 may be an opening for taking air into the housing 14 from the space to be air-conditioned. The housing 14 has a second air outlet 4 at a right rear portion of its upper wall. The second air outlet 4 may be an opening for blowing out air to the outside of the housing 14 as supply air. The air to be blown out may be a second air stream of air that has been taken into the housing 14 through the air inlet 3 and that has been cooled by passing through the cooling unit 10. The housing 14 has a first air outlet 5 at a left rear portion of its upper wall. The first air outlet 5 may be an opening for blowing out air to the outside of the housing 14 as exhaust air. The air to be blown out may be a first air stream of air that has taken into the housing 14 through the air inlet 3 and that has been subjected to sensible heat exchange with a second air stream. A flow path that extends from the air inlet 3 to the first air outlet 5 and through which a first air stream flows is referred to as a first flow path P1. A flow path that extends from the air inlet 3 to the second air outlet 4 and through which a second air stream flows is referred to as a second flow path P2.

[0026] The dust collection filter 20 collects dust from air taken through the air inlet 3, thereby reducing dust contamination inside the housing 14. The dust collection filter 20 is located between the air inlet 3 and the cooling unit 10 in both the first flow path P1 and the second flow path P2.

[0027] The cooling unit 10 includes an evaporative filter 21 and a heat exchanger 22. The heat exchanger 22 cools the space to be air-conditioned by lowering the ambient temperature using water supplied from the tank unit 7 that stores water to be supplied to first heat-exchange channels R1. As illustrated in FIG. 3, the heat exchanger 22 includes a sheet 23 that separates a first heat-exchange channel R1 and a second heat-exchange channel R2 from each other. According to the illustrative embodiment, the heat exchanger 22 includes multiple sheets 23, multiple first spacers 301, and multiple second spacers 302. In the heat exchanger 22, the sheets 23 are arranged in parallel to each other at predetermined intervals in a front-rear direction to separate the first heat-exchange channels R1 from the second heat-exchange channels R2. The first heat-exchange channels R1 allow a first air stream to flow therethrough. The second heat-exchange channels R2 allow a second air stream to flow therethrough.

[0028] Each sheet 23 may be formed of a thermally conductive resin or metal. Examples of the resin forming each sheet 23 include an ethylene vinyl alcohol copolymer resin (EVOH), and polyethylene terephthalate (PET) subjected to a hydrophilic treatment. Examples of the metal forming the sheets 23 include anodized aluminum, and stainless steel. In the illustrative embodiment, each sheet 23 has a thickness in the front-rear direction, and the thickness is preferably not less than 0.03 mm and not more than 0.1 mm. The sheets 23 include a first sheet 231, a second sheet 232, and a third sheet 233. In the illustrative embodiment, the first sheet 231, the second sheet 232, and the third sheet 233 may be identical in shape. Each sheet 23 has a first surface 25 and a second surface 31 on opposite sides. The first surface 25 defines a first heat-exchange channel R1. The second surface 31 defines a second heat-exchange channel R2. In the heat exchanger according to the illustrative embodiment, the sheets 23 whose first surfaces 25 face the front and the sheets 23 whose first surfaces 25 face the rear are alternately arranged in the front-rear direction, thereby providing the first heat-exchange channels R1 and the second heat-exchange channels R2 alternately in the front-rear direction. The first heat-exchange channels R1 are internal spaces defined in the heat exchanger 22 in the first flow path P1. The second heat-exchange channels R2 are internal spaces defined in the heat exchanger 22 in the second flow path P2. Intervals between the first heat-exchange channels R1 in the front-rear direction are defined by a thickness M1 of the first spacers 301. Intervals between the second heat-exchange channels R2 in the front-rear direction are defined by a thickness M2 of the second spacers 302. The thickness M1 of the first spacers 301 and the thickness M2 of the second spacers 302 represent dimensions of the first spacers 301 and the second spacers 302, respectively, in the front-rear direction, and are preferably not less than 2 mm and not more than 5 mm.

[0029] Hereinafter, a configuration of the heat exchanger 22 will be described using a module 29 for the heat exchanger 22. As illustrated in FIGS. 4A to 4C, the module 29 includes a first sheet 231, a second sheet 232, a third sheet 233, a pair of first spacers 301, and a pair of second spacers 302. The second sheet 232 is located next to the first sheet 231, and the third sheet 233 is located next to the second sheet 232. The pair of first spacers 301 is located between the first sheet 231 and the second sheet 232, and the pair of second spacers 302 are located between the second sheet 232 and the third sheet 233. The module 29 is the smallest repeating unit of the heat exchanger 22. The heat exchanger 22 includes multiple modules 29 arranged in the front-rear direction. As illustrated in FIGS. 4A to 4C, in each sheet 23, the first surface 25 includes a reference surface 26 and multiple protrusions 27 that protrude relative to the reference surface 26 in a thickness direction T of the sheet 23. In the illustrative embodiment, the thickness direction T of the sheet 23 corresponds to the front-rear direction. The reference surface 26 may be a flat surface extending in both the up-down direction and a right-left direction. Each adjacent two of the protrusions 27 defines a groove portion therebetween on the reference surface 26. Each groove portion is contiguous with a non-groove portion of the reference surface 26.

[0030] More specifically, as schematically illustrated in the enlarged view of FIG. 4A, when two adjacent protrusions 27, for example, a protrusion 271 and a protrusion 272, are located adjacent to each other in the up-down direction, a groove portion 281 is defined between the protrusion 271 and the protrusion 272 in the up-down direction. The groove portion 281 is indicated by cross hatching and has a rectangular shape in a rear view of the drawing. A left end and a right end of the groove portion 281 are contiguous with a non-groove portion 283 of the reference surface 26. The non-groove portion 283 is not located between the protrusion 271 and the protrusion 272 in the up-down direction on the reference surface 26, and may correspond to the entirety or part of the reference surface 26 except for the groove portions 281. The non-groove portion 283 is indicated by hatching in the drawing. In the illustrative embodiment, the reference surface 26 is a flat surface. Thus, the reference surface 26 has no asperities or inclinations that may obstruct flow of water due to surface tension, between each groove portion 281 and the non-groove portion 283 on the reference surface 26. When two adjacent two protrusions 27, for example, a protrusion 272 and a protrusion 273, are located adjacent to each other in the right-left direction, a groove portion 282 is defined between the protrusion 272 and the protrusion 273 in the right-left direction. The groove portion 282 is indicated by cross hatching and has a rectangular shape in a rear view of the drawing. An upper end and a lower end of the groove portion 282 are continuous with a non-groove portion 284 of the reference surface 26. The non-groove portion 284 is indicated by hatching in the drawing. That is, groove portions such as groove portions 281 and 282 are not completely surrounded on all four sides by the protrusions 27. Each protrusion 27 is surrounded on all four sides by the reference surface 26, except for a protrusion 27 that is aligned with an edge of a sheet 23.

[0031] Each protrusion 27 has, in a virtual plane parallel to the reference surface 26, a first length L1 in a longitudinal direction and a second length L2 in a lateral direction orthogonal to the longitudinal direction. The first length L1 is longer than the second length L2 in each protrusion 27. In the illustrative embodiment, the protrusions 27 may be identical in shape except for protrusions 27 that are in contact with respective ends of the heat exchanger 22. In each sheet 23 whose first surface 25 faces the front, each projection 27 has a rectangular shape elongated in the right-left direction in a front view, and has a square shape in a right view. The longitudinal direction of each protrusion 27 intersects a first direction K1 that extends from an inlet E1 toward an outlet E2 of a first heat-exchange channel R1. The inlet E1 of the first heat-exchange channel R1 may be an opening that allows a first air stream to enter the heat exchanger 22. The heat exchanger 22 has the inlet E1 at one of side surfaces. The outlet E2 of the first heat-exchange channel R1 may be an opening that allows the first air stream to exit from the heat exchanger 22. The heat exchanger 22 has the outlet E2 at the opposite side surface to the one side surface having the inlet E1. In the illustrative embodiment, the inlet E1 is located at an upper surface of the heat exchanger 22, and the outlet E2 is located at a lower surface of the heat exchanger 22. The longitudinal direction of each protrusion 27 corresponds to the right-left direction, and is orthogonal to a downward direction which may be the first direction K1 that extends from the inlet E1 to the outlet E2 of the first heat-exchange channel R1. The protrusions 27 are grouped by row. Each row includes a group of protrusions 27 that are at the same position in the up-down direction and adjacent protrusions 27 are separated at an interval of L4 in the right-left direction, which corresponds to the longitudinal direction of the protrusions 27. The protrusions 27 included in adjacent rows in the up-down direction are located at different positions in the right-left direction. More specifically, for example, the protrusions 272 and 273 are located below and adjacent to the protrusion 271 in the up-down direction. The protrusion 271 extending in the right-left direction overlaps both a right end portion of the protrusion 272 and a left end portion of the protrusion 273. Any area within a range in which the first sheet 231 extends in the right-left direction includes the extension range of any of the protrusions 27 of the first sheet 231. That is, the extension range of the first sheet 231 in the right-left direction does not include any area that is not within the extension range of any of the protrusions 27.

[0032] The length L1 of the protrusions 27 is preferably not less than 0.2 mm and not more than 10 mm. The length L2 of the protrusions 27 is preferably not less than 0.1 mm and not more than 1 mm. Two adjacent protrusions 27 are separated from each other at an interval of L3 or L4 that is preferably not less than 0.1 mm and not more than 1.0 mm. The protrusions 27 has a height L5 that is preferably not less than 0.1 mm and not more than 1.0 mm. As illustrated in FIG. 4B, the height L5 of the protrusions 27 represents an amount by which the protrusions 27 protrude from the reference surface 26. With consideration given to a water retention capacity of the first heat-exchange channel R1, the height L5 of the protrusions 27 is preferable to be substantially equal to the interval of L3 or L4 between two adjacent protrusions 27. The height L5 of the protrusions 27 is preferably within a range of 0.7 to 1.3 times each of the intervals of L3 and L4 between two adjacent protrusions 27, and more preferably, within a range of 0.8 to 1.2 times each of the intervals of L3 and L4 between two adjacent protrusions 27.

[0033] The first heat-exchange channel R1 is defined by a first surface 25 of the first sheet 231, a first surface 25 of the second sheet 232, and the pair of first spacers 301. The first surface 25 of the second sheet 232 faces and is spaced from the first surface 25 of the first sheet 231 in the thickness direction T. The pair of first spacers 301 is located between the first sheet 231 and the second sheet 232. Each first spacer 301 is elongated in the up-down direction. As illustrated in FIG. 4C, one of the pair of first spacers 301 extends from an upper end to a lower end of the first sheet 231, between a right end portion of the first sheet 231 and a right end portion of the second sheet 232. Likewise, the other of the pair of first spacers 301 extends from the upper end to the lower end of the first sheet 231, between a left end portion of the first sheet 231 and a left end portion of the second sheet 232. In the up-down direction, the positions where the protrusions 27 of the first sheet 231 are located are different from the positions where the protrusions 27 of the second sheet 232 are located. Each protrusion 27 of the first sheet 231 is positioned to face the reference surface 26 of the second sheet 232 in the thickness direction T. A minimum distance between the first sheet 231 and the second sheet 232 in the front-rear direction is equal to the difference between the thickness M1 of the first spacers 301 and the height L5 of the protrusions 27 relative to the reference surface 26.

[0034] The second heat-exchange channel R2 is defined by a second surface 31 of the second sheet 232, a second surface 31 of the third sheet 233, and the pair of second spacers 302. The second surface 31 of the third sheet 233 faces and is spaced from the second surface 31 of the second sheet 232 in the thickness direction T. The pair of second spacers 302 is located between the second sheet 232 and the third sheet 233. As illustrated in FIG. 4B, one of the pair of second spacers 302 extends from a right end to a left end of the second sheet 232, between an upper end portion of the second sheet 232 and an upper end portion of the third sheet 233. Likewise, the other of the pair of second spacers 302 extends from the right end to the left end of the second sheet 232, between a lower end portion of the second sheet 232 and a lower end portion of the third sheet 233. The second surface 31 of each sheet 23 has recesses 33 that define part of a second heat-exchange channel R2 and are recessed relative to the second heat-exchange channel R2. Each recess 33 is located on the second surface 31 and aligned with a respective protrusion 27. The protrusions 27 and the recesses 33 of each sheet 23 may be, for example, formed by embossing a flat sheet.

[0035] As illustrated in FIG. 2, air is taken into the housing 14 through the air inlet 3. A first air stream of the air flows downward through the first heat-exchange channels R1 of the heat exchanger 22. A second air stream of the air flows rightward through the second heat-exchange channels R2 of the heat exchanger 22. That is, a second direction K2 and the first direction K1 are orthogonal to each other. The second direction K2 extends from an inlet E3 toward an outlet E4 of each second heat-exchange channel R2 in the heat exchanger 22. The first direction K1 extends from the inlet E1 toward the outlet E2 of each first heat-exchange channel R1 in the heat exchanger 22. The inlet E3 of each second heat-exchange channel R2 may be an opening that allows second air stream to enter the heat exchanger 22. The heat exchanger 22 has the inlets E3 at one of side surfaces. The outlet E4 of each second heat-exchange channel R2 may be an opening that allows the second air stream to flow out from the heat exchanger 22. The heat exchanger 22 has the outlets E4 at another side surface opposite to the one side surface having the inlets E3. In the illustrative embodiment, the inlets E3 are located at a left side surface of the heat exchanger 22, and the outlets E4 are located at a right side surface of the heat exchanger 22.

[0036] The evaporative filter 21 is configured to lower the temperature around the evaporative filter 21 using the heat of evaporation of water supplied from the tank unit 7, for cooling the space to be air-conditioned. In the illustrative embodiment, the evaporative filter 21 is located downstream of the heat exchanger 22 and upstream of the second air outlet 4 in the second flow path P2 for second air stream. More specifically, the evaporative filter 21 is located to the right of the heat exchanger 22 and below an upper wall of the housing 14. The evaporative filter 21 may be a rectangular filter having water absorbency. The evaporative filter 21 may be formed, for example, of rayon, polyester, or nonwoven fabric. The evaporative filter 21 is located such that a rectangular left surface thereof faces a right surface of the heat exchanger 22. A second air stream passes through the evaporative filter 21 from the right surface of the heat exchanger 22 is primarily cooled by the heat exchanger 22. The evaporative filter 21 is further configured to cool the second air stream that has been primarily cooled by the heat exchanger 22, using heat of vaporization of water supplied from the tank unit 7. That is, the air conditioner 1 is configured to cool the second air stream in two steps using the heat exchanger 22 and the evaporative filter 21.

[0037] The water supply unit 15 includes the tank unit 7, a mineral adsorbent 16, a pump 11, a controller 12, a water pipe 8, a second water-supply unit 17, and a first water-supply unit 18. The tank unit 7 is configured to store water to be supplied to the evaporative filter 21 and the heat exchanger 22. The tank unit 7 includes a drain pan 13, collecting channels 9, a first tank 71, and second tanks 72. The drain pan 13 is located below the heat exchanger 22 and above the first tank 71. The drain pan 13 has a rectangular dish-like shape. The drain pan 13 is configured to receive remaining water that has not been evaporated in the heat exchanger 22.

[0038] The collecting channels 9 are provided for collecting water remaining in the cooling unit 10. The collecting channels 9 include a first collecting channel 91 and a second collecting channel 92. The first collecting channel 91 allows remaining water that has not been evaporated in the evaporative filter 21 to pass therethrough to the first tank 71. The second collecting channel 92 allows water that has been received by the drain pan 13 to pass therethrough to the first tank 71. Each of the first collecting channel 91 and the second collecting channel 92 has one end, which serves as an outlet, located closer to the first tank 71 than the other end. The outlets of the first collecting channel 91 and the second collecting channel 92 are directed toward an opening of the first tank 71. The water to be supplied to the evaporative filter 21 and the heat exchanger 22 includes water collected into the first tank 71 via the collecting channels 9.

[0039] The first tank 71 is an example of a container. The first tank 71 may have, for example, a rectangular box shape and have an opening at its top. The first tank 71 is located below the evaporative filter 21 and the drain pan 13. The first tank 71 is configured to store water to be supplied to the evaporative filter 21 and the heat exchanger 22.

[0040] Each second tank 72 may have, for example, a rectangular box shape. The second tanks 72 are located above the first tank 71, and are detachably attachable to the housing 14. The second tanks 72 are detached from the housing 14 and are filled with, for example, tap water. Then, the second tanks 72 are attached to the housing 14. Each second tank 72 has a bottom surface that is positioned above a bottom surface of the first tank 71. Each second tank 72 has a supply port 73 at its bottom surface. When a water level in the first tank 71 reaches a predetermined level or lower, water is supplied from the second tanks 72 to the first tank 71 via the supply ports 73. In the illustrative embodiment, two second tanks 72 are provided. A total volume of the two second tanks 72 is greater than a volume of the first tank 71.

[0041] The mineral adsorbent 16 is located in the water supply unit 15 and adsorbs mineral content in water. In the illustrative embodiment, the mineral adsorbent 16 may be a cartridge that contains adsorbent beads and is detachably attachable to a bottom of the first tank 71. The adsorbent beads adsorb minerals such as magnesium and calcium contained in water.

[0042] The pump 11 is located in the first tank 71. The pump 11 is configured to supply water stored in the first tank to the evaporative filter 21 and the heat exchanger 22. The controller 12 may be implemented, for example, by a microcomputer or similar device. The controller 12 is connected to the pump 11 by a communication line. The pump 11 is configured to be driven or stopped based on a control signal output from the controller 12. The controller 12 is located, for example, below the first tank 71.

[0043] The water pipe 8 provides communication between the pump 11, the evaporative filter 21, and the heat exchanger 22. That is, the first tank 71 is in communication with the evaporative filter 21 and the heat exchanger 22 via the pump 11 and the water pipe 8. The water pipe 8 is branched into a first water pipe 81 and a second water pipe 82 in the vicinity of the evaporative filter 21 and the heat exchanger 22. The first water pipe 81 is in communication with the second water-supply unit 17. The second water pipe 82 is in communication with the first water-supply unit 18.

[0044] The second water-supply unit 17 is located at an upper portion of the evaporative filter 21. In the illustrative embodiment, the second water-supply unit 17 may be a part of the evaporative filter 21. The water supplied to the second water-supply unit 17 is dropped onto the evaporative filter 21 via a first water supply port. The evaporative filter 21 is made of a water-absorbing material. Thus, the water dropped onto the evaporative filter 21 permeates into the evaporative filter 21.

[0045] The first water-supply unit 18 is located above the heat exchanger 22. In the heat exchanger 22, the closer a portion is to the first water-supply unit 18, the more its temperature decreases due to the water supplied from the first tank 71, as compared with a portion farther from the first water-supply unit 18. The first water-supply unit 18 is located in the vicinity of the evaporative filter 21, that is, above a right end portion of the heat exchanger 22. The location where the first water-supply unit 18 is provided is downstream of the flow of second air stream in the second direction K2. Thus, such an arrangement of the first water-supply unit 18 may increase cooling efficiency for second air stream.

[0046] The first fan 61 is an example of a fan. The first fan 61 is located in the vicinity of the first air outlet 5, and is configured to convey a first air stream. The second fan 62 is located in the vicinity of the second air outlet 4, and is configured to convey a second air stream. Each of the first fan 61 and the second fan 62 may be, for example, a centrifugal fan, such as a sirocco fan or a propeller fan. Air flows through the air conditioner 1 from the air inlet 3 to the second air outlet 4 or to the first air outlet 5. Assuming that the air inlet 3 is the most upstream end and the second air outlet 4 or the first air outlet 5 is the most downstream end in the direction of the air flow, the first fan 61 and the second fan 62 are located downstream of the cooling unit 10 in the direction of the air flow. Since the first fan 61 and the second fan 62 are located downstream of the cooling unit 10, the first fan 61 and the second fan 62 function as intake fans that maintain negative pressure within the airflow path in the air conditioner 1.

[0047] The fan motor 6 is a drive source of the first fan 61 and the second fan 62. A shaft extending leftward from the fan motor 6 is connected to the first fan 61. Another shaft extending rightward from the fan motor 6 is connected to the second fan 62. The partition plate 63 is located between the first fan 61 and the second fan 62 to avoid mixing of the first air stream conveyed by the first fan 61 and the second air stream conveyed by the second fan 62.

[0048] The fan motor 6 is located between the partition plate 63 and the first fan 61. The fan motor 6 is located in the first flow path P1. The first air stream conveyed by the first fan 61 cools the fan motor 6. Thus, the air conditioner 1 may efficiently cool the fan motor 6 using cold energy of the first air stream without increasing the temperature of the second air stream conveyed by the second fan 62.

[0049] Referring to FIG. 2, a description will be provided on an operation of the air conditioner 1 having the above-described configuration. The air conditioner 1 drives the fan motor 6 to take in air from the space to be air-conditioned through the air inlet 3. The air passes the dust collection filter 20 and then enters the heat exchanger 22. The air taken into the heat exchanger 22 splits into a first air stream and a second air stream. The first air stream flows through the first flow path P1 and the second air stream flows through the second flow path P2.

[0050] The air conditioner 1 drives the pump 11 to supply water from the first tank 71 to the first heat-exchange channel R1 and the evaporative filter 21. The water supplied to the first heat-exchange channel R1 and the evaporative filter 21 is collected into the first tank 71 via the collecting channels 9. The first water-supply unit 18 drops, to the first heat-exchange channel R1, the water supplied from the first tank 71 by the pump 11. The reference surface 26 and the protrusions 27 of the first surface 25 of each sheet 23 that defines a corresponding first heat-exchange channel R1 form fine channels. The water dropped from the first water-supply unit 18 spreads along the fine channels defined by the reference surface 26 and the protrusions 27 in both the right-left and up-down directions due to the surface tension of the water, thereby spreading the spaces between the protrusions 27.

[0051] The first air stream flows downward along the fine channels defined by the reference surface 26 and the protrusions 27 that are elongated in the right-left direction. The first air stream and the water dropped from the first water-supply unit 18 are mixed in the first heat-exchange channel R1. The water accumulated in the first tank 71 includes the water that has been collected from the evaporative filter 21 after the air conditioner 1 is operated and that has been cooled by heat of evaporation. Thus, depending on an operating state of the air conditioner 1, the temperature of the water supplied from the first tank 71 may be lower than the temperature of the first air stream immediately after the first air stream enters the first heat-exchange channel R1. The first air stream is cooled by exchanging sensible heat with the water dropped from the first water-supply unit 18. The first air stream is also cooled by the latent heat of evaporation when the water dropped from the first water-supply unit 18 to the first heat-exchange channel R1 evaporates.

[0052] The second direction K2, which extends from the inlet E3 toward the outlet E4 of the second heat-exchange channel R2 in the heat exchanger 22, and the first direction K1, which extends from the inlet E1 toward the outlet E2 of the first heat-exchange channel R1 in the heat exchanger 22, are orthogonal to each other. The first air stream that flows through the first heat-exchange channel R1 is cooled by the water supplied from the first tank 71, and the second air stream is cooled by the first air stream. That is, in the heat exchanger 22, sensible heat is exchanged between the second air stream and the first air stream via the sheets 23. The first air stream flows downward through the first heat-exchange channel R1. When the first air stream reaches the drain pan 13, the flow direction of the first air stream is reversed. Thus, the first air stream then flows upward. As indicated by a dot-and-dash line in FIG. 5, the first flow path P1 includes a section that extends upward from the drain pan 13 to the first air outlet 5 and is located behind the heat exchanger 22. After passing behind the heat exchanger 22, the first air stream passes near the fan motor 6 located in the first flow path P1, and is then discharged through from the first air outlet 5 to the outside of the air conditioner 1. When the first air stream passes near the fan motor 6, the first air stream cools the fan motor 6.

[0053] In the heat exchanger 22, the second air stream that flows rightward through the second heat-exchange channel R2 subsequently passes rightward through the evaporative filter 21. The water supplied from the first tank 71 is dropped onto the evaporative filter 21 via the second water-supply unit 17 located at the upper portion of the evaporative filter 21. The inside of the second flow path P2 is maintained at a negative pressure. Thus, the water supplied from the first tank 71 is drawn into the evaporative filter 21 through a water supply port located at the bottom surface of each second water-supply unit 17, and then permeates into the evaporative filter 21. The water that has permeated into the evaporative filter 21 is evaporated as the second air stream passes through the evaporative filter 21. As a result, the water evaporates and becomes water vapor, which is then contained in the second air stream. At this time, the latent heat of evaporation cools the second air stream, thereby causing the temperature of the second air stream to be lowered. The cooled second air stream is blown out to the space to be air-conditioned through the second air outlet 4 by the second fan 62.

[0054] The above-described configuration may thus enable the air conditioner 1 to perform two-step cooling on the second air stream that is to be blown to the space to be air-conditioned. The two-step cooling includes primary cooling by the heat exchanger 22 and secondary cooling by the evaporative filter 21. Therefore, the air conditioner 1 may further lower the temperature of the second air stream, for example, as compared with a direct evaporation method that uses only the evaporative filter 21.

[0055] The heat exchanger 22 of the air conditioner 1 according to first to fifth aspects will be described. In the air conditioner 1 according to the first to fifth aspects, only the configuration of the heat exchanger 22 differs from that of the above illustrative embodiment, while the other configurations are the same. In the first to fifth aspects, the thickness direction T of each sheet included in the heat exchanger 22 may be the front-rear direction. In the first to fifth aspects, the first direction K1 in which the first air stream flows through the first heat-exchange channel R1 in the heat exchanger 22 may be a downward direction, and the second direction K2 in which the second air stream flows through the second heat-exchange channel R2 in the heat exchanger 22 may be a rightward direction. As in the above illustrative embodiment, the configuration of each heat exchanger according to the first to fifth aspects will also be described using a module. Unless otherwise specified, a module according to each aspect includes a first sheet, a second sheet, a third sheet, a pair of first spacers, and a pair of second spacers. The second sheet is located next to the first sheet, and the third sheet is located next to the second sheet. The pair of first spacers is located between the first sheet and the second sheet. The pair of second spacer is located between the second sheet and the third sheet.

[0056] Referring to FIGS. 5A and 5B, a description will be provided on sheets 75 included in a module 120 for the heat exchanger 22 in the air conditioner 1 according to the first aspect. In FIG. 5B, some of the sheets 75 are schematically illustrated, and the spacers are omitted from the drawing. In the first aspect, the sheets 75 include a first sheet 124, a second sheet 125 next to the first sheet 124 with a gap D2 therebetween in the front-rear direction, and a third sheet 126 next to the second sheet 125 with a gap D3 therebetween in the front-rear direction. The first sheet 124, the second sheet 125, and the third sheet 126 have common structure as described below. More specifically, in the first aspect, each sheet 75 has a first surface 127 and a second surface 133 on opposite sides. The first surface 127 has a flat reference surface 128 and multiple protrusions 129. The protrusions 129 include first protrusions 130 and second protrusions 131. The second protrusions 131 are longer than the first protrusions 130 in a first length in a longitudinal direction or a second length in a lateral direction, or both of a first length in the longitudinal direction and a second length in the lateral direction.

[0057] In each sheet 75 according to the first aspect, the longitudinal direction of the first protrusions 130 and the longitudinal direction of the second protrusions 131 correspond to the right-left direction. The first protrusions 130 have a first length X5 in the longitudinal direction. The second protrusions 131 have a first length X6 in the longitudinal direction. The first length X5 is shorter than the first length X6. The first protrusions 130 have a second length X1 in the lateral direction. The second protrusions 131 have a second length X3 in the lateral direction. The second length X1 is shorter than the second length X3. In each sheet 75, rows Q1 and rows Q2 are alternately arranged at intervals of X2 in the up-down direction. Each row Q1 includes three first protrusions 130 that are aligned in the right-left direction, and adjacent protrusions 130 are separated from each other at an interval of X4. Each row Q2 has two second protrusions 131 that are aligned in the right-left direction and separated from each other at the interval of X4 in the right-left direction. In the first aspect, the interval of X2 and the interval of X4 are equal to each other. The second surface 133 has first recesses 134 and second recesses 135. Each first recess 134 is located on the second surface 133 and aligned with a respective first protrusion 130, and is dimensioned to correspond to the respective first protrusion 130. Each second recess 135 is located on the second surface 133 and at a position behind a respective second protrusion 131, and is dimensioned to correspond to the respective second protrusion 131. Each sheet 75 has a uniform thickness D1. Specifically, the thickness D1 at the first protrusions 130, the second protrusions 131, and the reference surface 128 is substantially the same.

[0058] The first sheet 124 and the third sheet 126 have the same pattern of arrangement of the rows Q1 and Q2 in the up-down direction. Nevertheless, the first sheet 124 and the second sheet 125 have different patterns of arrangement of the rows Q1 and Q2 in the up-down direction. Specifically, the first sheet 124 and the third sheet 126 each have five rows in which rows Q1, Q2, Q1, Q2, and Q1 are arranged in this order at the intervals of X2 in the up-down direction. The second sheet 125 has six rows in which rows Q2, Q1, Q2, Q1, Q2, and Q1 are arranged in this order at the intervals of X2 in the up-down direction. The first protrusions 130 and the second protrusions 131 of the first sheet 124 face the reference surface 128 of the second sheet 125. The first protrusions 130 and the second protrusions 131 of the second sheet 125 face the reference surface 128 of the first sheet 124. Thus, a minimum gap between the first sheet 124 and the second sheet 125 in the front-rear direction is equal to the difference between the gap D2 defined by the thickness of the first spacers and a height D4 of the first protrusions 130 and the second protrusions 131.

[0059] Referring to FIGS. 6A and 6B, a description will be provided on sheets 76 included in a module 210 for the heat exchanger 22 in the air conditioner 1 according to the second aspect. In FIGS. 6A and 6B, some of the sheets 76 are schematically illustrated, and the spacers are omitted from the drawing. In the second aspect, the sheets 76 include a first sheet 224, a second sheet 225 next to the first sheet 224 with the gap D2 therebetween in the front-rear direction, and a third sheet 226 next to the second sheet 225 with the gap D3 therebetween in the front-rear direction. The first sheet 224, the second sheet 225, and the third sheet 226 may be identical in shape. In the second aspect, each sheet 76 has a first surface 227 and a second surface 243 on opposite sides. The first surface 227 has a flat reference surface 228 and multiple protrusions 229. The protrusions 229 include first protrusions 241 and second protrusions 242. In the sheets 76 according to the second aspect, the longitudinal direction of the first protrusions 241 and the longitudinal direction of the second protrusions 242 correspond to the up-down direction.

[0060] Each of the first protrusions 241 and the second protrusions 242 has a first length in the longitudinal direction and a second length in the lateral direction. In each of the first protrusions 241 and the second protrusions 242, at least one of the first length or the second length decreases as each of the first protrusions 241 and the second protrusions 242 protrudes farther from the reference surface 228. In the second aspect, each of the first protrusions 241 and the second protrusions 242 has a truncated rectangular pyramid shape. More specifically, in each of the first protrusions 241 and the second protrusions 242, both the first length and the second length decrease as each of the first protrusions 241 and the second protrusions 242 protrudes farther from the reference surface 228. The first protrusions 241 have a first length X5 in a portion contiguous with the reference surface 228, and have a first length X9 in a portion that is farthest from the reference surface 228. The first length X5 is longer than the first length X9. The first protrusions 241 has a second length X1 in a portion contiguous with the reference surface 228, and have a second length X7 in a portion that is farthest from the reference surface 228. The second length X1 is longer than the second length X7. Similarly, the second protrusions 242 have a first length X6 and a first length X10. The first length X6 is longer than the first length X10. The second protrusion 242 have a second length X3 and a second length X8. The second length X3 is longer than the second length X8. Each first protrusion 241 has a side surface that is inclined by an angle of Z1 with respect to the reference surface 228. The angle of Z1 is preferably within a range from 70 to 89.9 degrees, and more preferably, within a range from 88 to 89 degrees. The same applies to an angle of Z2 of a side surface of each second protrusion 242 with respect to the reference surface 228.

[0061] The second surfaces 243 has first recesses 245 and second recesses 246. Each first recess 245 is aligned with a respective first protrusion 241 and is dimensioned to correspond to the respective first protrusion 241. Each second recesses 246 is aligned with a respective second protrusion 242 and is dimensioned to correspond to the respective second protrusion 242. Each sheet 76 has a uniform thickness. Specifically, the thickness at the first protrusions 241, the second protrusions 242, and the reference surface 228 is substantially the same. The protrusions 27 including the protrusions 241 and 242 are grouped by column. Each column includes a group of protrusions 241 or a group of protrusions 242 that are at the same position in the right-left direction and adjacent protrusions 241 or 242 are separated at the interval of X4 in the up-down direction, which corresponds to the longitudinal direction of the protrusions 241 or 242. In each sheet 76, columns Q3 and columns Q4 are alternately arranged at the intervals of X2 in the right-left direction. Each column Q3 includes three first protrusions 241 that are aligned in the up-down direction, and adjacent protrusions 241 are separated from each other at the interval of X4 in the up-down direction. Each column Q4 includes two second protrusions 242 that are aligned in the up-down direction and separated from each other at the interval of X4 in the up-down direction. In the second aspect, the interval of X2 and the interval of X4 are equal to each other. Each first protrusion 241 of the first sheet 224 is positioned to face a respective first protrusion 241 of the second sheet 225. Each second protrusion 242 of the first sheet 224 is positioned to face a respective second protrusion 242 of the second sheet 225. A minimum gap between the first sheet 224 and the second sheet 225 in the front-rear direction is equal to the difference between the gap D2 defined by a thickness of the first spacers and twice the height D4 of the first protrusions 241 and the second protrusions 242.

[0062] Referring to FIGS. 7A and 7B, a description will be provided on sheets 77 included in the heat exchanger 22 of the air conditioner 1 according to the third aspect. In FIGS. 7A and 7B, some of the sheets 77 are schematically illustrated. In the third aspect, each sheet 77 has a first surface 305 and a second surface 307 on opposite sides. The first surface 305 includes a reference surface 303 and multiple protrusions 304 that protrude relative to the reference surface 303 in a thickness direction T of the sheets 77. In the third aspect, the reference surface 303 may be a flat surface. Each protrusion 304 has a V-shape when viewed from a direction perpendicular to the reference surface 303, that is, in a front view or rear view. Each protrusion 304 also has a V-shape in cross section parallel to the reference surface 303, which is the same V-shape as that of each protrusion 304 of FIG. 7A. Each protrusion 304 has a bottom tip, a portion 341 that extends upward to the right from the bottom tip, and a portion 342 that extends upward to the left from the bottom tip. The longitudinal direction of each of the portions 341 and 342 intersects a downward direction that is the first direction K1 in which the first air stream flows. Each adjacent two of the protrusions 304 define a groove portion therebetween. The groove portion is contiguous with a non-groove portion of the reference surface 303. More specifically, a groove portion 321 defined between a protrusion 311 and a protrusion 312 of the protrusions 304 is contiguous with a non-groove portion of the reference surface 303 at a lower right portion and an upper left portion of the groove portion 321. The groove portion 321 is a part of the reference surface 303 that is defined between a lower end of the protrusion 311 and an upper right end of the protrusion 312. A groove portion 322 defined between the protrusion 311 and a protrusion 313 is contiguous with a non-groove portion of the reference surface 303 at an upper right portion and a lower left portion of the groove portion 322. The groove portion 322 is a part of the reference surface 303 that is defined between a lower end of the protrusion 311 and an upper left end of the protrusion 313. In each sheet 77, rows Q5 and rows Q6 are alternately arranged at intervals of W2 in the up-down direction. Each row Q5 includes three protrusions 304 that are aligned in the right-left direction, and adjacent protrusions 304 are separated from each other at an interval of W1 in the right-left direction. Each row Q6 includes four second protrusions 304 that are aligned in the right-left direction, and adjacent protrusions 304 are separated from each other at the interval of W1 in the right-left direction. In the right-left direction, the bottom tip of each protrusion 304 included in the row Q5 is positioned substantially at the midpoint between adjacent protrusions 304 included in the row Q6.

[0063] In the third aspect, the heat exchanger 22 of the air conditioner 1 further includes strip-like water absorbers 98 and 99 that are positioned in a first heat-exchange channel R1 and to which water is supplied from the first tank 71. The water absorbers 98 and 99 may be made of a material that absorbs water, for example, cloth, nonwoven fabric, or sponge. The water absorbers 98 and 99 each have a thickness that is determined in consideration of a dimension of the first heat-exchange channel R1 in the thickness direction T. The water absorber 98 has a rectangular shape and extends over a left end portion of the first surface 305 from an upper end to a lower end in each sheet 77. The water absorber 99 has a rectangular shape and extends in the right-left direction over the third row Q5 from the top on the first surface 305 of each sheet 77. At least one of the protrusions 304 is in contact with the water absorber 98 or 99. In the third aspect, the leftmost protrusion 304 included in each row is in contact with the water absorbers 98. The three protrusions 304 included in the third row Q5 from the top are in contact with the water absorber 98.

[0064] Referring to FIGS. 8A and 8B, a description will be provided on sheets 78 included in the heat exchanger 22 of the air conditioner 1 according to the fourth aspect. In FIGS. 8A and 8B, one of the sheets 78 is schematically illustrated, and the spacers are omitted from the drawing. In the fourth aspect, each sheet 78 has a first surface 402 and a second surface 409 on opposite sides. The first surface 402 includes a reference surface 403 and multiple protrusions 404 that protrude relative to the reference surface 403 in a thickness direction T of the sheets 78. Each protrusion 404 has a rectangular prism shape that is elongated in the right-left direction. The second surface 409 may be a flat surface, and have no recess. Each sheet 78 has rows Q7, Q8 and Q9. The rows Q7 and Q9 each include three protrusions 404 that are aligned in the right-left direction, and adjacent protrusions 404 are separated from each other at intervals of X14 in the right-left direction. Each row Q8 includes two protrusions 404 that are aligned in the right-left direction and separated from each other at the interval of X14 in the right-left direction. In the up-down direction, a row Q8 is located between a row Q7 and a row Q9. The rows Q7, Q8, and Q9 are arranged in this order from the top at intervals of X12 in the up-down direction. In the fourth aspect, the interval of X12 and the interval of X14 are equal to each other. The first surface 402 has sections R3, R4, and R5. The protrusions 404 are positioned in the sections R3 and R5 but not positioned in the section R4. The section R4 has a flat reference surface 403 only. The section R4 is located between the section R3 and the section R5 in the up-down direction. Each of the sections R3 and R5 has a dimension X15 in the up-down direction. The section R4 has a dimension X16 in the up-down direction. The dimension X15 is shorter than the dimension X16. For example, each sheet 78 may be produced by first producing a sheet that is elongated in the up-down direction, and then cutting the elongated sheet into sheet pieces to conform to the size of heat exchangers. Adjusting the cutting positions of the elongated sheet may accommodate various types of heat exchangers with different sizes. This may facilitate adaptation to model changes of the air conditioner 1 and enable easy expansion of the product lineup. In the heat exchanger 22 according to the fourth aspect, the sheets 78 may include a first sheet and a second sheet. In one example, the sheets 78 may be arranged such that protrusions 404 of the first sheet and protrusions 404 of the second sheet face each other. In another example, the sheets 78 may be arranged such that the protrusions 404 of the first sheet face a reference surface 403 of the second sheet. The sheets 78 may be, for example, injection-molded sheets.

[0065] Referring to FIGS. 9A to 9C, a description will be provided on a module 40 for the heat exchanger 22 of the air conditioner 1 according to a fifth aspect. In FIGS. 9A to 9C, the module 40 for the heat exchanger 22 is schematically illustrated. The module 40 for the heat exchanger 22 includes multiple sheets 50. The sheets 50 includes a first sheet 51, a second sheet 52 next to the first sheet 51, and a third sheet 53 next to the second sheet 52. In the fifth aspect, the first sheet 51, the second sheet 52, and the third sheet 53 may be identical in shape. Each of the first sheet 51, the second sheet 52, and the third sheet 53 has a square shape with its four corners cut out in a virtual plane parallel to its own reference surface 56, that is, in a front view or rear view. That is, each sheet 50 has cutouts 49 at its four corners. Each cutout 49 has an L shape. Each sheet 50 has a first surface 54 and a second surface 55 on opposite sides. The first surface 54 includes a reference surface 56 and multiple protrusions 57 that protrude relative to the reference surface 56 in a thickness direction T of the sheets 50. The reference surface 56 may be a flat surface. The second surface 55 has recesses 60. Each recess 60 is aligned with a respective protrusion 57 and is dimensioned to correspond to the respective protrusion 57. The sheets 50 may be, for example, embossed sheets obtained by embossing a flat sheet. The preferred size and arrangement of the protrusions 57 are the same as those in the illustrative embodiment, and therefore a detailed description will be omitted.

[0066] In the first sheet 51 and the third sheet 53, the longitudinal direction of the protrusions 57 corresponds to the up-down direction. In the second sheet 52, the longitudinal direction of the protrusions 57 corresponds to the right-left direction. The second sheet 52 corresponds to the first sheet 51 rotated by 90 degrees about an axis passing through the center M of the first surface 54 of the first sheet 51 and corresponding to a direction in which the protrusions 57 extend in a thickness direction T. In the fifth aspect, the first surface 54 of each sheet 50 faces toward the front in the heat exchanger 22. In the fifth aspect, the sheets 50 having the protrusions 57 whose longitudinal direction corresponds to the up-down direction and the sheets 50 having the protrusions 57 whose longitudinal direction corresponds to the right-left direction are alternately arranged in the front-rear direction, thereby providing the first heat-exchange channels R1 and the second heat-exchange channels R2 alternately in the front-rear direction in the heat exchanger 22.

[0067] Each first heat-exchange channel R1 is defined by a first surface 54 of a first sheet 51, a second sheet 52, and a pair of first spacers. The second sheet 52 faces and is spaced from the first surface 54 of the first sheet 51 in the thickness direction T. The pair of first spacers is located between the first sheet 51 and the second sheet 52. Each first spacer extends in the first direction K1 that extends from the inlet E1 toward the outlet E2 of the first heat-exchange channel R1. At least one of the first spacers may be a first protruding wall 58 that is integral with the first sheet 51. The first protruding wall 58 protrudes relative to the protrusions 57 from the reference surface 56 of the first sheet 51 in the thickness direction T, and is in contact with the second sheet 52. In the fifth aspect, both of the first spacers are first protruding walls 58 that extend parallel to each other in the up-down direction. The protrusions 57 are positioned between the first protruding walls 58 in the right-left direction. The first protruding walls 58 are identical in shape. The first protruding walls 58 have a length L7 in the longitudinal direction. The length L7 is longer than a first length L1 of the protrusions 57. The first protruding walls 58 have a length L8 in the lateral direction. The length L8 is longer than a second length L2 of the protrusions 57. The first protruding walls 58 have a height L9 from the reference surface 56. The height L9 is greater than twice of a height L5 of the protrusions 57 from the reference surface 56.

[0068] As illustrated in FIG. 9B, each first heat-exchange channel R1 is defined by a first surface 54 of a first sheet 51, a second surface 55 of a second sheet 52, and a pair of first protruding walls 58. The second surface 55 of the second sheet 52 faces and is spaced from the first surface 54 of the first sheet 51 in the thickness direction T. The first protruding walls 58 are in contact with the second surface 55 of the second sheet 52. One of the first protruding walls 58 may also be referred to as a first protruding wall 581, and the other may also be referred to as a first protruding wall 582. The first protruding wall 581 is located at a right end portion of the first sheet 51. The first protruding wall 582 is located at a left end portion of the first sheet 51.

[0069] As illustrated in FIG. 9C, each second heat-exchange channel R2 is defined by a first surface 54 of a second sheet 52, a third sheet 53, and a pair of second spacers. The third sheet 53 faces and is spaced from the first surface 54 of the second sheet 52 in the thickness direction T. The pair of second spacers is located between the second sheet 52 and the third sheet 53. Each second spacer extends in the second direction K2 that extends from the inlet E3 toward the outlet E4 of the second heat-exchange channel R2. At least one of the second spacers may be a second protruding wall 59 that is integral with the second sheet 52. The second protruding wall 59 protrudes relative to the protrusions 57 from the reference surface 56 of the second sheet 52 in the thickness direction T, and is in contact with the third sheet 53. In the fifth aspect, both of the second spacers are second protruding walls 59 that extend parallel to each other in the up-down direction. One of the second protruding walls 59 may also be referred to as a second protruding wall 591, and the other may also be referred to as a second protruding wall 592. The second protruding wall 591 is located at a lower end portion of the second sheet 52. The second protruding wall 592 is located at an upper end portion of the second sheet 52.

[0070] The module 40 for the heat exchanger 22 includes multiple separators 45 that separate a first heat-exchange channel R1 and a second heat-exchange channel R2. Each separator 45 has a square column shape conforming to a respective cutout 49. The separators have a length in the front-rear direction. The length is greater than a gap between a frontmost sheet 50 and a rearmost sheet 50 of the heat exchanger 22 in the front-rear direction. Each separator 45 extends from a front end to a rear end of the heat exchanger 22. Two adjacent surfaces of each separator 45 are in contact with the cutouts 49 of the sheets 50. The separators 45 include a first separator 41, a second separator 42, a third separator 43, and a fourth separator 44. An upper surface and a left surface of the first separator 41 are in contact with the lower right cutout 49 of each sheet 50. The first separator 41 is in contact with a lower end 584 of the first protruding wall 581 of the first sheet 51 and a right end 594 of the second protruding wall 591 of the second sheet 52. A lower surface and a left surface of the second separator 42 are in contact with the upper right cutout 49 of each sheet 50. The second separator 42 is in contact with an upper end 583 of the first protruding wall 581 of the first sheet 51 and a right end 596 of the second protruding wall 592 of the second sheet 52. An upper surface and a right surface of the third separator 43 are in contact with the lower left cutout 49 of each sheet 50. The third separator 43 is in contact with a lower end 586 of the first protruding wall 582 of the first sheet 51 and a left end 593 of the second protruding wall 591 of the second sheet 52. A lower surface and a right surface of the fourth separator 44 are in contact with the upper left cutout 49 of each sheet 50. The fourth separator 44 is in contact with an upper end 585 of the first protruding wall 582 of the first sheet 51 and a left end 595 of the second protruding wall 592 of the second sheet 52. Each separator 45 is located at a respective corner of each sheet 50, and is in contact with the corresponding ends of the first protruding wall 58 and the second protruding wall 59, and the third sheet 53.

[0071] According to the illustrative embodiment and the first to fifth aspects, an air conditioner includes a heat exchanger and a first tank. The heat exchanger includes a sheet that separates a first heat-exchange channel and a second heat-exchange channel. The first tank is configured to store water to be supplied to the first heat-exchange channel. The sheet includes a first surface. The first surface includes a reference surface and multiple protrusions. The first surface defines the first heat-exchange channel. The protrusions protrude relative to the reference surface in a thickness direction T of the sheet. Each adjacent two of the protrusions define a groove portion therebetween on the reference surface. The groove portion is contiguous with a non-groove portion of the reference surface. With this configuration, water is likely to remain around each protrusion due to surface tension of water. Thus, the air conditioner may retain the water in the first heat-exchange channel without a nonwoven fabric. A groove portion defined between two adjacent protrusions is contiguous with the non-groove portion. Thus, as compared with a case where a groove portion is not contiguous with to the non-groove portion, water may be more likely to move to the groove portion in the air conditioner. The water retained in the first heat-exchange channel may dry more easily as compared with a heat exchanger using a nonwoven fabric. Therefore, the sheet of the air conditioner may contribute to facilitating maintenance without reducing the water retention capability of the first heat-exchange channel as compared with the case where a nonwoven fabric is used.

[0072] The reference surface is a flat surface. Each protrusion has, in a virtual plane parallel to the reference surface, a first length in a longitudinal direction and a second length in a lateral direction orthogonal to the longitudinal direction. In each protrusion, the first length is longer than the second length. With this configuration, water is likely to remain around each protrusion due to surface tension of water. Thus, the air conditioner may retain the water in the first heat-exchange channel without a nonwoven fabric. Additionally, as compared with a case where the reference surface is curved or where the first length and the second length are equal to each other, water may be more likely to move to the groove portion in the air conditioner.

[0073] The longitudinal direction of each protrusion intersects a first direction that extends from an inlet toward an outlet of the first heat-exchange channel. Even when the first direction corresponds to an up-down direction, water may be likely to remain around each protrusion in the air conditioner, thereby contributing to maintaining the water retention capability of the first heat-exchange channel.

[0074] The heat exchanger includes multiple sheets. The sheets includes a first sheet and a second sheet. The first heat-exchange channel is defined by a first surface of the first sheet, a first surface of the second sheet, and a pair of first spacers. The first surface of the second sheet faces and is spaced from the first surface of the first sheet in the thickness direction. The pair of first spacers is located between the first sheet and the second sheet. In the air conditioner, as compared with a case where the first heat-exchange channel is in contact with the first surface of the first sheet and the second surface of the second sheet, the presence of the first sheet and the second sheet may contribute to improving the water retention capability of the first heat-exchange channel and the cooling efficiency of the second air stream.

[0075] The air conditioner includes a first fan that causes a first air stream to flow through the first heat-exchange channel. Each protrusion of the first sheet is positioned to face the reference surface of the second sheet in the thickness direction. The first sheet and the second sheet may thus contribute to reducing air resistance when the first air stream flows through the first heat-exchange channel as compared with a case where protrusions are arranged in positions facing each other on the first sheet and the second sheet in the thickness direction. Therefore, since the air conditioner may reduce the pressure loss of the first air stream, a downsized first fan can be used as compared with a case where protrusions are arranged at positions facing each other on the first sheet and the second sheet.

[0076] According to the second aspect of FIGS. 6A and 6B, the protrusions have a first length in the longitudinal direction and a second length in the lateral direction. In each of the protrusions, at least one of the first length or the second length decreases as each of the protrusions protrudes farther from the reference surface. In the air conditioner according to the second aspect, the presence of the protrusions may increase the water-retaining area, along which water spreads along the reference surface, on the first surface, as compared with a case where the first length and the second length of each protrusion are equal regardless of the distance from the reference surface. Therefore, in the air conditioner of the second aspect, the presence of such protrusions may contribute to improving the water retention capability in the first heat-exchange channel and increasing the cooling efficiency of the second air stream.

[0077] According to the third aspect of FIGS. 7A and 7B, the reference surface is a flat surface. The protrusions include at least one protrusion that has a V-shape in cross section parallel to the reference surface. Such a V-shaped protrusion tends to allow water to accumulate at a lower end of an inner apex of the protrusion. Therefore, the presence of the V-shaped protrusion may contribute to improving the water retention capability in the first heat-exchange channel and increasing the cooling efficiency of a second air stream, as compared with an air conditioner without such a V-shaped protrusion in a sheet.

[0078] According to the first aspect of FIGS. 5A and 5B, the protrusions include a first protrusion and a second protrusion, each having a first length in the longitudinal direction and a second length in the lateral direction. At least one of the first length or the second length of the second protrusion is longer than the corresponding length of the first protrusion. In the air conditioner, arranging a combination of first and second protrusions as appropriate on the first surface may contribute to facilitating adjustment of the water retention capacity of the first heat-exchange channel.

[0079] According to the illustrative embodiment and the first to fifth aspects, the length of the protrusions in the lateral direction is preferably not less than 0.1 mm and not more than 1 mm. Further, the interval between two adjacent protrusions is preferably not less than 0.1 mm and not more than 1.0 mm. Such a configuration may allow water to remain around each protrusion, as compared with a case where the length of the protrusions in the lateral direction is greater than 1.0 mm or where the interval between two adjacent protrusions is greater than 1.0 mm. In addition, water may be likely to move to the groove portion due to the surface tension of water. Furthermore, such a configuration may reduce deformation of the protrusions or clogging of the groove portion with foreign matter such as dust, as compared with a case where the length of the protrusions in the lateral direction at the distal end farthest from the reference surface is less than 0.1 mm or where the interval between two adjacent protrusions is less than 0.1 mm.

[0080] The height of the protrusions is preferably not less than 0.1 mm and not more than 1.0 mm. In the air conditioner including such protrusions, water may be likely to move to the groove portion due to surface tension of water, as compared with a case where the height of the protrusions is greater than 1.0 mm.

[0081] According to the third aspect of FIGS. 7A and 7B, the air conditioner includes a water absorber that is positioned in the first heat-exchange channel and to which water is supplied from the first tank. At least one of the protrusions is in contact with the water absorber. Such a configuration may thus enable the water absorber to contribute to supplying water to the first heat-exchange channel without using a water spray unit in the air conditioner. Using a downsized water absorber, as compared to known water absorbers, may increase the ease of maintenance of the air conditioner.

[0082] According to the illustrative embodiment and the first, second, third, and fifth aspects, the sheet has a second surface having a recess. The recess defines part of the second heat-exchange channel and is recessed relative to the second heat-exchange channel. In the air conditioner, the second surface of the sheet may contribute to increasing a surface area of the second surface defining the second heat-exchange channel, as compared with a case where a sheet has no recess as in the fourth aspect. Therefore, the presence of the recess may contribute to increasing the cooling efficiency of a second air stream, as compared with an air conditioner without a recess in the second surface.

[0083] The second surface has multiple recesses. Each recess is aligned with a respective protrusion. Each recess may be formed at a position corresponding to a respective protrusion by a relatively simple process. With this configuration, the heat exchange efficiency may be enhanced as compared with a case where the protrusions and the recesses are not located at respective corresponding positions.

[0084] According to the illustrative embodiment, the air conditioner includes a water supply unit and a mineral adsorbent. The water supply unit includes a first tank and a water pipe. The water pipe is connected to the first tank and allows water to flow therethrough. The mineral adsorbent is located in the water supply unit and adsorbs mineral content in water. In the air conditioner, the mineral adsorbent adsorbs and removes mineral content from the water in the first tank. Thus, the mineral adsorbent may contribute to reducing clogging of a groove portion between two adjacent protrusions by mineral deposits and a decrease of water retention capacity of the first heat-exchange channel.

[0085] According to the fifth aspect, the heat exchanger includes multiple sheets. The sheets includes a first sheet and a second sheet. A first heat-exchange channel is defined by a first surface of the first sheet, the second sheet, and a pair of first spacers. The second sheet faces and is spaced from the first surface of the first sheet in the thickness direction. The pair of first spacers is located between the first sheet and the second sheet. Each first spacer extends in a first direction that extends from an inlet toward an outlet of a first heat-exchange channel. At least one of the first spacers may be a first protruding wall that is integral with the first sheet. The first protruding wall protrudes relative to protrusions from a reference surface of the first sheet in the thickness direction, and is in contact with the second sheet. According to the fifth aspect, the sheets of the air conditioner may contribute to reducing the weight of the heat exchanger as compared with a case where a pair of first spacers are provided separately from the first sheet.

[0086] Both of the first spacers are first protruding walls that extend parallel to each other. Each sheet has a first surface and a second surface opposite to the first surface. A first heat-exchange channel is defined by a first surface of a first sheet, a second surface of a second sheet, and a pair of first spacers. The second surface of the second sheet faces and is spaced from the first surface of the first sheet in the thickness direction. The first spacers are in contact with the second surface of the second sheet. According to the fifth aspect, the sheets of the air conditioner may contribute to reducing the weight of the heat exchanger as compared with a case where at least one of the pair of first spacers is provided separately from the first sheet.

[0087] In the air conditioner according to the fifth aspect, the second sheet is identical to the first sheet in shape. Thus, manufacturing cost of the heat exchanger may be reduced as compared with a case where the first sheet and the second sheet have different shapes.

[0088] The sheets further includes a third sheet. A first heat-exchange channel is defined by a first surface of a second sheet, a third sheet, and a pair of second spacers. The third sheet faces and is spaced from the first surface of the second sheet in the thickness direction. The pair of second spacers is located between the second sheet and the third sheet. Each second spacer extends in a second direction that extends from an inlet toward an outlet of a second heat-exchange channel. At least one of the second spacers may be a second protruding wall that is integral with the second sheet. The second protruding wall protrudes relative to protrusions from a reference surface of the second sheet in the thickness direction, and is in contact with the third sheet. According to the fifth aspect, the sheets of the air conditioner may contribute to reducing the weight of the heat exchanger as compared with a case where a pair of second spacers are provided separately from the second sheet.

[0089] Both of the first spacers are first protruding walls that extend parallel to each other. Both of the second spacers are second protruding walls that extend parallel to each other. According to the fifth aspect, the sheets of the air conditioner may contribute to reducing the weight of the heat exchanger as compared with a case where at least one of a pair of first spacers is provided separately from the first sheet and at least one of a pair of second spacers is provided separately from the second sheet. The first protruding walls, which are the pair of first spacers, extend parallel to each other. Such a configuration may stabilize the air flow in the first heat-exchange channel as compared with a case where the first spacers extend in directions that intersect with each other. The second protruding walls, which are the pair of second spacers, extend parallel to each other. Such a configuration may stabilize the air flow in the second heat-exchange channel as compared with a case where the second spacers extend in directions that intersect with each other.

[0090] According to the fifth aspect, the heat exchanger includes multiple separators that separate a first heat-exchange channel and a second heat-exchange channel. The separators include a first separator, a second separator, a third separator, and a fourth separator. The first separator is in contact with a downstream end of one of the first protruding walls of the first sheet in the first direction, and with a downstream end of one of the second protruding walls of the second sheet in the second direction. The second separator is in contact with an upstream end of the one of the first protruding walls of the first sheet in the first direction, and with a downstream end of the other of the second protruding walls of the second sheet in the second direction. The third separator is in contact with a downstream end of the other of the first protruding walls of the first sheet in the first direction, and with an upstream end of the one of the second protruding walls of the second sheet in the second direction. The fourth separator is in contact with an upstream end of the other of the first protruding walls of the first sheet in the first direction, and an upstream end of the other of the second protruding walls of the second sheet in the second direction. In the air conditioner according to the fifth aspect, the separators may reduce mixing between an air stream that flows through the first heat-exchange channel and an air stream that flows through the second heat-exchange channel, with a relatively simple configuration.

[0091] According to the fifth aspect, the second sheet and the third sheet are identical to the first sheet in shape. Thus, manufacturing cost of the heat exchanger may be reduced as compared with a case where the sheets have different shapes.

[0092] The reference surface is a flat surface. Each of the first sheet, the second sheet, and the third sheet has a square shape with its four corners cut out in a virtual plane parallel to its own reference surface. According to the fifth aspect, the heat exchanger includes multiple separators that separate a first heat-exchange channel and a second heat-exchange channel. Each separator is located at a respective corner of each sheet, and is in contact with the corresponding ends of the first protruding wall and the second protruding wall, and the third sheet. In the air conditioner, the separators may reduce mixing between an air stream that flows through the first heat-exchange channel and an air stream that flows through the second heat-exchange channel, with a relatively simple configuration.

[0093] The air conditioner and the heat exchanger of the disclosure are not limited to the above-described embodiment or aspects. While the disclosure has been described in detail with reference to the specific embodiment thereof, this is merely an example, and various changes, arrangements and modifications may be applied therein without departing from the spirit and scope of the disclosure. For example, the following changes, arrangements and modifications may be applied as appropriate.

[0094] In the air conditioner, at least one of the evaporative filter and the dust collection filter may be omitted, or the arrangement of the evaporative filter in the second flow path may be changed as appropriate. The evaporative filter may have a sheet similar to those provided in the heat exchanger. The air conditioner may have separate air inlets for first air stream and for second air stream. The configuration of the water supply unit may be changed as appropriate. The pump might not necessarily be located inside the first tank. Alternatively, a main body of the pump may be located outside the first tank, and the water in the first tank may be conveyed through a channel that communicates between the pump and the first tank. The controller may be positioned, for example, on an outer peripheral surface of a wall that defines the first flow path extending from the heat exchanger to the first air outlet, and may be cooled by a first air stream via the wall defining the first flow path.

[0095] In the air conditioner, the pump may be omitted, and the heat exchanger may be located at a position where at least one of the protrusions included in the first surface of the sheet defining a first heat-exchange channel can contact the water accumulated in the tank unit. With configuration, the water accumulated in the tank unit moves along fine channels defined by the reference surface and the protrusions, due to the surface tension of the water. In this case, the water accumulated in the tank unit may be supplied to the protrusions through the water absorbers as in the third aspect.

[0096] The configuration of the second tank may be changed as appropriate. For example, the second tank may include an electromagnetic valve that can be controlled by the controller and a sensor that is configured to detect a water level in the first tank. In this case, the second tank may be configured such that the electromagnetic valve is opened for a certain period to supply water to the first tank when the sensor detects that the water level in the first tank is below a predetermined level. The air conditioner may include a single second tank or three or more second tanks. The fan may be omitted as appropriate, and the arrangement of the fan in the housing may be changed. The fan motor may be positioned in the second flow path instead of the first flow path. The fan motor may be provided for each of the fans. The mineral adsorbent may be omitted. The arrangement of the mineral adsorbent may be changed as appropriate. The mineral adsorbent may be positioned at any part of the water supply unit, such as at the water pipe.

[0097] The configuration of the heat exchanger may be changed as appropriate. In a case where the heat exchanger has multiple first heat-exchange channels, protrusions may be provided only at the first surface of the sheet defining at least one of the first heat-exchange channels. The size or shape of each sheet may be changed as appropriate. The first direction in which a first air stream flows through the heat exchanger and the second direction in which a second air stream flows through the heat exchanger may be changed as appropriate, as long as the first direction and the second direction intersect each other. The reference surface of the first surface might not necessarily be a flat surface. In one example, the reference surface may have fine asperities as long as the fine asperities are smaller in size than the protrusions and do not obstruct the flow of water due to surface tension. In another example, the reference surface may be a curved surface. In this case, the height of the protrusions may be defined based on the amount by which a particular protrusion protrudes from a portion of the reference surface having an average thickness. The protrusions might not necessarily be identical in shape, and may be changed as appropriate. For example, the protrusions may have a square shape, circular shape, polygonal shape, or other shape in the virtual plane parallel to the reference surface, in which the first length in the longitudinal direction is equal to the second length in the lateral direction orthogonal to the longitudinal direction. As in the second aspect, the longitudinal direction of the protrusions may be parallel to the first direction that extends from the inlet toward the outlet of the first heat-exchange channel. The longitudinal directions of the protrusions may be the same as or different from each other. The formation density of the protrusions on the first surface may be changed as appropriate. The first surface of each sheet might not necessarily have protrusions on part or entirety of the portion that is contact with at least one of the pair of spacers. The second surface of each sheet might not necessarily have protrusions on part or entirety of the portion that is contact with at least one of the pair of spacers.

[0098] As in the fifth aspect, in a pair of sheets defining a first heat-exchange channel, only a first surface of one of the sheets may have protrusions. Alternatively, in pairs of sheets defining first heat-exchange channels, a first surface of at least one of the pairs of sheets may have protrusions.

[0099] The protrusions of the first sheet may be located at respective positions facing the protrusions of the second sheet in the thickness direction. The first length of the protrusions in the longitudinal direction, the second length of the protrusions in the lateral direction, the intervals between adjacent protrusions, and the height of the protrusions from the reference surface may each be changed as appropriate. The water absorbers in the heat exchanger may have different shapes, may be made of different materials, or may be located at different positions, as appropriate. The second surfaces of the sheets might not necessarily have any recess. In a case where protrusions are provided on a second surface, recesses might not necessarily be located at positions corresponding to the protrusions. Sheets may be produced using any appropriate method in consideration given to the thickness and material of the sheets as well as the shape and size of protrusions to be formed on the sheets.

[0100] In the first sheet according to the fifth aspect, only one of the spacers may be a first protruding wall. In one example, one of the pair of first spacers defining a first heat-exchange channel may be a first protruding wall of the first sheet, and the other may be a first protruding wall of the second sheet located apart from the first sheet in the thickness direction. In this case, the pair of second spacers defining a second heat-exchange channel may be the same spacers as that used in the illustrative embodiment. In another example, one of the pair of first spacers defining a first heat-exchange channel may be a first protruding wall of the first sheet, and the other may be the same spacer as that used in the illustrative embodiment. In the fifth aspect, the first sheet, the second sheet, and the third sheet might not necessarily be identical in shape. In the heat exchanger according to the fifth aspect, some or all of the separators may be omitted. The shape or arrangement of the separators may be changed. The cutouts for separators may be omitted as appropriate, and one or more of the arrangement, shape, and size may be changed. Each separator may be a rod that has an outer peripheral surface conforming to a respective cutout and is elongated in the thickness direction of the sheets. In one example, when each cutout has an arc shape, each separator may have a cylinder having an outer peripheral surface conforming to a respective arc-shaped cutout. Each separator may be an L-shaped plate member configured to contact a respective corner of each sheet having four corners. The first spacers may extend in directions intersecting each other. The second spacers may extend in directions intersecting each other. The above-described changes, arrangements, or modifications may be combined as appropriate as long as no contradiction arises.