AN AIR CONDITIONING APPARATUS

Technical Field

The present invention relates to air conditioning apparatus and more particularly but not exclusively to air conditioning apparatus that also provides for the harvesting of water.

Background of the Invention

Described in USA Patents 682900, 6935132 and 5829513 as well as Australian Patent Applications 2004215315 and 2005266848 are various air conditioning apparatus that employ heat exchangers. The abovementioned air conditioning apparatus do not provide for the harvesting of water from the air being treated.

Typically air conditioning apparatus have employed a refrigerant that is compressed and expanded and pass through various heat exchangers to provide air of a desired temperature. These known heat exchangers require considerable energy for their operation and therefore are costly to run.

Object of the Invention

It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

Summary of the Invention There is disclosed herein an air conditioning apparatus including: a heat exchanger having a first air path and a second air path, each air path having an inlet and an outlet, with heat transfer to take place between air passing along the first path with respect to the air passing along the second path; a first air pump, said first air pump providing for the flow of air along the first path from the inlet to the outlet of the first path; a second air pump, said second air pump providing for the flow of air along said second path from the inlet to the outlet of said second path; a delivery member to deliver a dissolved desiccant to said first path so that an exothermic reaction will take place along said first path to heat air passing therealong and therefore heat air passing along said second path;

a collection chamber located to receiving the dissolved desiccant from the first path outlet; and a water/desiccant pump to take the dissolved desiccant from said chamber to provide for the delivery of the dissolved desiccant to said delivery member. Preferably, said delivery member is a nozzle, and apparatus includes a further nozzle, said further nozzle being positioned to deliver a water spray to the inlet of said second path to thereby lower temperature of air passing along said second path.

Preferably, said apparatus includes an evaporative cooling pad downstream of said first path outlet through which air passes to be delivered to a room interior. Preferably, said apparatus includes a medium to which the dissolved desiccant is delivered, and a further air pump operatively associated with said medium to cause air to pass therethrough to cause water in said medium to be evaporated.

Preferably, said apparatus includes a reservoir to receive water from said medium with the desiccant disclosed therein, and wherein said water pump communicates with said reservoir and said first nozzle to provide for the delivery of the dissolved desiccant to said first nozzle.

Preferably, said apparatus includes a further collection chamber, said further collection chamber receiving air from said second path and air from said medium, and a further reservoir, said further reservoir being provided to collect water from said further collection chamber.

In a further preferred form, said apparatus includes a heater to heat air from said first path prior to delivery to said interior.

Preferably, said apparatus is adapted to receive air from said interior for delivery to said second air pump. Preferably, said heat exchanger is a first heat exchanger, and said apparatus further includes: a second heat exchanger, said second heat exchanger providing a third air path and a fourth air path each with an inlet and an outlet, with heat transfer to take place between air passing along the fourth air path with respect to air passing along the third air path; and a duct to provide for delivery of air from said third path to said second path.

Preferably, said apparatus further includes a delivery member to deliver dissolved desiccant to said third path.

Preferably, said apparatus further includes a delivery member to deliver water to said fourth path.

Preferably, the or each heat exchanger includes: a plurality of stacked frames, each frame being of a rectangular configuration so as to have four sides, a plurality of baffles extending between two opposite sides of said four sides so that adjacent baffles define a passage extending between said opposite sides; a sheet material located between adjacent frames and covering the passages of the adjacent frames and providing for the transfer of heat between fluid passing between the passages of adjacent frames; a plurality of the passages of each frame include an entry passage portion, a generally central passage portion and an exit passage portion, with the generally central passage portion extending diagonally relative to said opposite sides; and wherein a plurality of the frames provide passages providing said first path, while other frames provide a plurality of passages providing said second path. Preferably, in respect of each passage, arcuate passage portions join the entry passage portion and the exit passage portion to the central passage portion.

Preferably, said central passage portion extends at approximately 45° to said opposite sides.

Preferably, each of said opposite sides includes a first side portion and a second side portion, with the first side portions being located directly opposite each other, and the second side portions being located directly opposite each other and wherein in respect of each passage of said plurality of passages, the inlet portions extending from a first one of the first side portions, and the exit portions extending from the second side portion of the other opposite side. Preferably, each side portion extends approximately half the length of the respective side.

Preferably, said entry portions and said exit portions extend generally normal to their respective side.

Preferably, said frames are arranged so that the central passage portions of adjacent frames are substantially perpendicular.

Preferably, said sheet material is substantially moisture impervious.

Preferably, said sheet material is sheet Mylar (Registered Trademark).

There is further disclosed herein a method of cooling air, said method including the steps of: delivering air containing water to a first path; delivering air to a second path that is in a heat transfer relationship to the first path; delivering a desiccant to said first path so that water in said first path and said desiccant provide a solution passing along said first path to thereby generate heat that is at least partly transferred to said second path; delivering water in liquid form to said second path so as to at least partly travel therealong with air passing along said second path and so that heat transferred from said first path to said second path causes at least part evaporation of water in said second path to thereby cool the air passing along said second path.

Preferably, said method includes the steps of collecting the dissolved desiccant from said first path and evaporating water therefrom and returning the desiccant for delivery to said first path.

Preferably, when said desiccant is delivered to said first path it is delivered in a water solution.

Preferably, said water and desiccant solution is delivered to said first path in spray form. Preferably, said desiccant is delivered to said first path at a downstream location thereof.

In an alternative preferred form, said desiccant is delivered to said first path at an upstream location thereof.

Preferably, water is delivered to said second path in spray form. Preferably, said method includes: passing air along a third path; passing air along a fourth path, with the third path being in heat transfer relationship with said fourth path with air from said first path being delivered to a downstream position of said fourth path so that warm air from said first path pass along said fourth path.

Preferably, water is delivered to said third path so as to pass therealong and to be heated by heat transfer from said fourth path to cause at least part evaporation of water passing along said third path to cool air passing along said third path.

Brief Description of the Drawings

Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Figure 1 is a schematic sectioned side elevation of an air conditioning apparatus; Figure 2 is a schematic sectioned side elevation of a modification of the apparatus of Figure 1;

Figure 3 is a schematic sectioned side elevation of a modification of the apparatus of Figure 2;

Figure 4 is a schematic parts exploded isometric view of a portion of a heat exchanger including frames and sheet materials to separate the frames;

Figure 5 is a schematic sectioned end elevation of portion of the heat exchanger of Figure 4;

Figure 6 is a schematic sectioned side elevation of portion of the heat exchanger of Figure 4; Figure 7 is the schematic plan view of a frame employed in the heat exchanger of

Figure 4;

Figure 8 is a schematic end elevation of the frame of Figure 7;

Figure 9 is a schematic end elevation of the frame of Figure 7;

Figure 10 is a schematic end elevation of the frame of Figure 7; Figure 11 is a schematic isometric view of a stack of the frames of Figure 7;

Figure 12 is a schematic top plan view of the stack of Figure 11;

Figure 13 is a schematic sectioned side elevation of a modification of the apparatus of Figure 1;

Figure 14 is a schematic sectioned side elevation of a sole operated evaporator employed with the apparatus of Figure 13; and

Figure 15 is a schematic sectioned side elevation of a modification of the apparatus of Figure 1.

Detailed Description of the Preferred Embodiments

In Figures 4 to 12 of the accompanying drawings there is schematically depicted a heat exchanger 10. The heat exchanger 10 includes a plurality of heat exchanger frames

12 that are arranged in a stack 13, with adjacent frames separated by a length 14 of sheet material 15, as best seen in Figure 5. The length 14 is arranged along a serpentine path so

as to provide a plurality of pockets 16. Located in each pocket is a respective one of the frames 12.

In this embodiment each of the frames 12 is of a rectangular configuration and more particularly a square configuration as best seen in Figure 8. The stack 13 is of a parallelepiped configuration as best seen in Figure 12.

Each frame 12 is generally flat (generally planar) and in this embodiment is square in configuration. Each frame 12 has four sides 16, 17, 18 and 19. The sides 17 and 19 are generally flat strips 21 and do not have any apertures. The opposite sides 16 and 18 each include a first side portion 22 or 23, and second side portions 24 or 25. The side portions 23 and 24 are also generally flat strips and do not have any apertures, while the side portions 22 and 25 each have a plurality of apertures 26 or 27.

Extending between the side portions 22 and 25 is a plurality of baffles 28 that are essentially strips or flanges, with a passage 29 being located between each adjacent pair of baffles 28. The baffles 28 are arranged so that each aperture 26/27 is aligned with a respective one of the passages 29. Preferably at least some of the passages 29 are divided longitudinally by a dividing baffle 30. Accordingly in operation a fluid can enter via one of the apertures 26/27 and flow along the respective passage 29 to exit via the other aperture 26/27. The passages 29 of adjacent passages 29 are separated by the length 14.

Support members 31 extend between the sides 17, 18, 19 and 20 to aid in supporting the baffles 28 and 30 in the positions illustrated. In that regard it should be appreciated the support members 31 do not block the passages 29.

Each of the passages 29 includes a first passage portion 32 that extends from the side portion 22. Each passage 29 further includes a second passage portion 33 that extends from the side portion 25. In that regard the passage portions 32 and 33 extend generally normal form the respective side portions 22 and 25.

Each passage 29 further includes a diagonal generally central passage portion 34 that may be divided longitudinally by a respective one of the baffles 30. Each passage portion 34 is joined to its respective passage portions 32 and 33 by arcuate passage portions 35. As is best seen in Figure 11, each diagonal passage portion 34 extends at approximately 45° to the opposite sides 16 and 18. Accordingly at the passage portions 34 the baffles 28 and 30 also extend at approximately 45° to the sides 16 and 18.

The side portions 22 and 25 are provided with projections 36 that would aid the mounting thereto of ducting when the frames 12 are arranged in the stack 13.

Preferably the sides 16 and 18 are provided with ridges 37 that are engaged with a corresponding longitudinal recess 38 of the next adjacent frame 12 to provide for the alignment of the frames 12 and there securing in a stack 13.

As best seen in Figure 6, each frame 12 has a recess 38 within which the length 14 is located to be securely attached to the frames 12 by engagement of the ridges 37 on the recess 38.

The stack 13, as best seen in Figure 11 has four side faces 40 to 43, with the faces 41 and 43 having strips 21 so that they are essentially closed off. The faces 40 and 42 have the apertures 26 and 27 with the passages 29 extending therebetween so that fluid may flow between the faces 40 and 42.

The stack 13 is particularly formed by a plurality of the frames 12, that are stacked as follows. Each alternate frame is arranged in the orientation as shown in Figure

11. Every other frame is arranged with the frame 12 as shown in Figure 12 but rotated through 180° about the transverse axis 44. Accordingly the stack 13 provides four face portions, 45, 46, 47 and 48. The face portion 45 has apertures 26 as does the face portion

46. The face portions 47 and 48 have apertures 27. The passages 29 extending from the apertures 26 of face portion 46 communicate with the apertures 27 of the face portion 48.

Simultaneously the passages 26 of the face portion 45 communicate with the apertures 27 of the face portion 47. Accordingly the diagonal passage portions 34 of adjacent frames 12 are generally perpendicular.

Because the length 14 is interposed between adjacent frames 12, the passages 29 of adjacent frames 12 do not communicate in respect of fluid flow however there is transfer of heat between adjacent passages 29 of adjacent frames 12. For example, a fluid could enter the apertures 26 of the face 46 and travels through the passages 29 to exit via the apertures 27 in the face 48, while a fluid entering the apertures 27 of the face 47 would flow via passages 29 to the apertures 26 of the face 45, to provide for the transfer of heat from fluid passing from face portion 46 to face portion 48 to fluid passing from face portion 47 to face portion 45. To prevent water transfer through the sheet material

15 it could be formed of plastics material. Preferably it is Mylar (Registered Trade Mark).

The passages 29 extending between the face portions 46 and 48 provide a first fluid path, while the passages 29 extending between the face portions 45 and 47 provide a second fluid path.

The face portions 45, 46, 47 and 48 are generally planar with the apertures 26 and 27 arranged in linear rows. The rows of face portion 45 are offset relative to the rows of face portion 46, while the rows of face portion 48 are offset relative to the rows of face portion 47. As is best seen in Figure 12, the diagonal portions 34 of adjacent frames 12 are generally perpendicular. Marked in Figure 12 are two diagonal passage portions 34, as can be seen they are generally perpendicular.

In Figure 1 of the accompanying drawings there is schematically depicted an air conditioning apparatus 50. The apparatus 50 includes a heat exchanger 10, as described with reference to

Figures 5 to 13. However the heat exchanger 10 could also be a heat exchanger as described in any one of USA Patents 6829900, 6935132 or 5829513, or any one of the heat exchangers described in Australian Patent Applications 2004215315 or 2005266840, or International Patent Publication WO93.18360. The apparatus 50 is mounted on a wall 54 separating a room interior 53 from the exterior 55. The apparatus 50 has a housing 51 providing an inlet 52 that communicates with the interior 53 so as take the air thereform. The housing 51 also has an outlet 56 that delivers conditioned air to the interior 53.

The housing 51 also provides a collection chamber 57, which chamber 57 also serves as an inlet that takes air from the exterior 55. Below the chamber 57 is a further chamber 58 that also takes air from the exterior 55. An outlet 59 exhausts air to the exterior 55.

Located within the housing 51 is a heat exchanger that may be the heat exchanger 10 described with reference to Figures 4 to 12. The heat exchanger 10 has a first air path 60 and a second air path 61. The air path 60 would pass from face portion 46 to face portion 45, while the second air path 61 would pass from the face portion 47 to the face portion 48. Accordingly the first path 60 takes air from the chamber 57 (air from the exterior) for delivery to the outlets 56. The second path 61 takes air from the interior 53 via the inlet 52, for delivery to the outlet 59. Communicating with the first path 60 is a nozzle 62 that delivers a spray 63 to the face portion 48. The spray 63 is desiccant dissolved in water. Typically the desiccant would be lithium chloride however calcium chloride and lithium bromide may also be employed. The water with the dissolved desiccant enters the path 60 and flows

therealong to be received in the chamber 57. While passing along the path 60, the water with the desiccant absorbs further water from the air passing along the path 60 so that there is an exothermic reaction. This exothermic reaction raises the temperature within the path 60 and therefore heats air passing along the path 61. This therefore cools the air in the path 60. The more the dissolved desiccant is cooled, the greater the amount of water it will absorb from the air passing along the path 60, thereby adding to the exothermic reaction.

Air leaving the path 60 and entering the chamber 64 is therefore very dry prior to engaging the evaporative cooling pad 65. Operatively associated with the pad 65 are nozzles 66 that deliver water in spray form at the pad 65.

Air is drawn through the path 60, through the chamber 64 and through the pad 65 via an air pump in the form of a fan 67. The fan 67 delivers the air to the outlet 56 via a heater 68. The heater 68 is only active when required.

Associated with the path 61 is an air pump in the form of a fan 69. The fan 69 takes air from the inlet 52 (air from the interior 53) and delivers it via a chamber 70.

Located in the chamber 70 is nozzle 71 that delivers a water spray 72 to the downstream end of the path 61. The water delivered to the path 61 via the nozzle 72 cools the air passing along the path 61, to thereby reduce the temperature of the air passing along the path 61. The moist air and water passing along the path 61 is delivered to a chamber 73, the chamber 73 communicating with the outlet 59.

The water with the dissolved desiccant entering the chamber 57, flows to the lower end of the chamber 57 to be delivered to a porous medium in the form of an evaporative pad 74. An air pump in the form of a fan 75 causes air to pass through the pad 74 to cause the water therein to at least partly evaporate. The pad 74 communicates with a reservoir 77 that receives water and the dissolved desiccant. A pump 78 takes the water and dissolved desiccant from the reservoir 77 and delivers it under pressure to the nozzle 62 for reuse.

The fan 75 takes air from the chamber 58 and therefore from the exterior 55.

Between the fan 75 and the pad 74 is a heater 79 that is operated to cause water in the pad 74 to evaporate, thus concentrating the desiccant.

Air delivered to the chamber 73 from the path 61 is cooler than the substantially saturated hot air being delivered to the chamber 73 via the pad 74, thus causing water to

condense in the chamber 73 for delivery and accumulation in the reservoir 76. The water in the reservoir 76 is potable and therefore is most usable.

Preferably the fans 67, 69 and 75 are electrically operated and can source power from solar panels or a mains power supply. In the embodiment of Figure 1 air flows through the paths 60 and 61 are in general opposite directions.

In Figure 2 there is schematically depicted an air conditioning apparatus 80 that is a modification of the apparatus 50. The apparatus 80 is mounted on a wall 81 that separates the interior 82 of a building to the exterior 83. The apparatus 80 has an outer housing 84 that provides an inlet 85 that takes air from the interior 82, and an outlet 86 that delivers air to the interior 82. The apparatus 80 has a further outlet 87 that delivers air to the exterior 83 as well as two further inlets 88 and 89 that take air from the exterior 83.

Located internally of the housing 84 is a heat exchanger 10. In this embodiment the heat exchanger 10 has two paths 90 and 91, with the air flowing in the same general direction through the heat exchanger 10. The path 90 extends from face portion 47 to face portion 45, while the path 91 extends from face portion 48 to face portion 46.

A first air pump in the form of a fan 92 delivers air to the path 91, while second air pump in the form of a fan 93 delivers air to the path 90. The fan 92 takes air from the inlet 88 and delivers it to the path 91 from where it exits via the outlet 86. The fan 93 takes air from the inlet 85 and delivers it to the path 90 to exit via the outlet 87.

Located between the path 91 and the fan 92 is a nozzle 173 that delivers a spray

94 of water in which there is dissolved a desiccant such as lithium chloride. The spray enters the path 91, with an exothermic reaction taking place in the path 91 to heat the air passing therethrough. Essentially the water with the lithium chloride dissolved therein dissolves further water contained in the air stream delivered in the path 91.

There is a heat transfer between the paths 91 and 90 so that air passing along the path 91 is cooled by air passing along the path 90. The air passing along the path 90 is cooled via a water spray 95 delivered via the nozzle 96. The spray is directed at face portion 47.

The dried air is delivered to a collection chamber 97 communicating with the outlet 86.

The outlet 86 includes an evaporative cooling pad 98 which is operative to cool air being delivered to the interior 82. A heater 99 is also provided and is operated should the air being delivered to the interior 82 require heating.

The chamber 97 collects water and desiccant coming from the path 91 and drains it to a lower end thereof communicating with a regenerative pad 100. The pad 100 is a porous medium allowing for the passage of water with the desiccant therethrough as well as the passage of air across the pad 100. The water (with the desiccant dissolved therein) is delivered to a reservoir 101 after being concentrated by the removal of water evaporating from the pad 100. An air pump in the form of a fan 102 takes air from the inlet 89 and causes it to pass through the pad 100. Water exiting the pad 100 is delivered to the reservoir 101. A pump 103 takes the water with the desiccant dissolved therein from the reservoir 101 and delivers it under pressure to the nozzle 137.

A heater 104 is located between the fan 102 and pad 100 and is operated to heat air delivered to the pad 100 to aid in evaporating water in the pad 100. Down stream of the path 90 is an outlet chamber 105 to which cooled moist air from the path 90 is delivered.

The hot almost saturated air entering the chamber 105 via the pad 100 is cooled by air entering the chamber 105 from the path 90. Accordingly water condenses in the chamber 105. The water that condenses in the chamber 105 is collected in the reservoir 106 from where it can be pumped to the nozzle 96 or used for other purposes. In that regard it should be appreciated the water in the reservoir 106 is potable.

Associated with the pad 98 is a nozzle or pipe 107 that delivers water to the evaporative cooling pad 98. The nozzle 107 could receive water from the reservoir 106. The pump 108 delivers water to the nozzle 96 and nozzle 107.

In Figure 3 there is schematically depicted an air conditioning apparatus 110.

The apparatus 110 is a modification of the apparatus 50 and the apparatus 80. In this embodiment the apparatus 110 is located externally of the building and communicates with the interior of the building via ducts 111 and 112. Air via the duct 112 delivers air to the interior of the building while the duct 111 takes air from the interior of the building.

The apparatus 110 has a housing 113 that has an outlet 114 that provides for communication with the duct 112, and an inlet 115 that communicates with the duct 111 to receive air therefrom.

The housing 113 has a further outlet 116 that exhausts air to the exterior, as well as inlets 117 and 118 that take air from the exterior.

Located internally of the housing 115 is a heat exchanger 10 that provides air paths 119 and 120. The apparatus 110 has a first air pump in the form of a fan 121 that takes air from the duct 111 and delivers it to the path 119 from where it exits via the outlet 116. A second air pump in the form of a fan 122 draws air from the path 120, the path 120 taking air from the inlet 118. As can be seen from Figure 3, air along the paths 119 and 120 pass in opposite directions. Downstream of the path 120 is a chamber 123 that has a nozzle 124 that delivers a spray 125 to the face 48 to which the path 120 extends. The spray is a water having dissolved in it a desiccant such as lithium chloride. The spray enters the path 120 with an exothermic reaction taking place due to the absorption of moisture in the air passing along the path 120. Accordingly air in the path 120 is heated. Located downstream of the nozzle 124 is an evaporative cooling pad 125 that receives water from nozzles 126. Accordingly air being delivered to the duct 112 has been dried by passing along the path 120, and subsequently cooled by the pad 125 through which it passes. A heater 127 is also provided should the air being delivered to the fan 122 require heating. Downstream of the fan 121 is a nozzle 128 that delivers a water spray to the face

47 to cool the air passing along the path 119. Accordingly air passing along the path 120 is cooled by the air passing along the path 119.

The inlet 118 communicates with a collection chamber 128, that collects water and desiccant exiting the lower end of the path 120 and directs it to a lower end communicating with a regenerative pad 129. The pad 129 is a porous medium through which the water may pass to be collected in a reservoir 130. Air may also pass transversely through the pad 129, with the air stream being provided by a fan 131 that takes air from the inlet 117. A pump 133 takes the water (with the desiccant dissolved therein) from the reservoir 130 and delivers it to the nozzle 124. A heater 134 is provided to heat the air being delivered to the pad 129 to cause evaporation of water from the pad 129, thus concentrating the desiccant in the water delivered to the reservoir 130.

The warm moist air leaving the pad 129 and being delivered to the chamber 132, is cooled by the air exiting the path 119. This causes water in the chamber 132 to condense.

The condensed water is delivered to a reservoir 135. The water is potable and can be used for any number of purposes. However a pump 136 takes at least some of the water from the reservoir 135 and delivers it to the nozzles 126 and 128.

In the above described preferred embodiments, the reservoirs 77, 101 and 130 maybe enlarged to provide for the prolonged supply of dissolved desiccant. These enlarged reservoirs can provide for the delivery of the water and desiccant to the heat exchanger 10 to continue the heating of air passing therethrough should the heaters 79, 104 or 134 be inoperative. For example if these heaters are powered via solar panels, then they maybe inoperative at night.

In Figure 13 there is schematically depicted and air conditioning apparatus 150. The apparatus 150 is a modification of the embodiments of Figures 1, 2 and 3. The apparatus 150 receives air 151 and delivers air 152 back to the interior.

The apparatus 150 has an outer housing 153 provided with an outlet 154 and an inlet 155. The housing 153 has a further inlet 156 that takes in ambient air.

Located internally of the housing 153 is the heat exchanger 10. The face 48 takes air from the inlet 151 with the passages 91 extending therefrom to the face 48 that delivers the air to a chamber 157. The path 162 delivers air to the chamber 158.

A nozzle 159 delivers a concentrated desiccant in spray form to the face 48 so that the desiccant in droplet form is delivered to the path 161. A nozzle 160 delivers cooling water in spray form to the path 162.

The dissolved desiccant passing along the path 161 absorbs further water from air also passing along the path 161. This results in an exothermic reaction as described previously. Accordingly the temperature of air passing along the path 161 is raised. This therefore cools the air passing along the path 162 by causing evaporation of the water passing along path 162, so the cooled air is delivered to the chamber 158.

Any water entering the chamber 158 is delivered to a reservoir 163. Water from the reservoir 163 is delivered by pump 164 to the nozzle 160. The water and desiccant delivered to the chamber 157 passes through a pad 165 from which further water is evaporated and delivered to the chamber 158. The evaporated water upon reaching the cooled air in chamber 158 condenses and is delivered to the reservoir 163. A

concentrated dissolved desiccant is delivered to the reservoir 166. The water and dissolved desiccant is then taken via pump 167 and delivered under pressure to the nozzle 159.

Air is extracted from the chamber 158 via a spray suppression pad 168 by a circulating fan 169 that delivers the air via duct 170 to the face 47. Accordingly the air under pressure is caused to pass along the path 162 for delivery to the chamber 158. The fan 169 by creating a lower pressure in the chamber 158 draws air in through the inlet 156 and causes it to pass along the path 161 for delivery to the chamber 157.

The air 151 is drawn into the inlet 155 by a fan 171 and caused to pass through the pad 165. A heater 172 may also be provided to heat air prior to delivery to the pad 165.

A mist suppression pad 173 is provided at the outlet 154 and through which the air 152 passes.

In the embodiment of Figure 13, the air 151 would come from the interior or exterior of the room and the air 152 returned to the interior of the room. The air taken in through the inlet 156 would be taken from the exterior. However it should be appreciated that the air conditioning apparatus 151 could also be an air conditioning apparatus in respect of a refrigeration system in that the air conditioning apparatus 150 could take the air 151 from an internal space of a refrigerator and return the air 152 to the interior of the refrigerator. In such instances, the air 152 could have a temperature in the range of I ⁰ C to 10 ⁰ C.

In the above described preferred embodiment of Figure 13, the apparatus 150 could also be used to harvest water by taking exterior air that is moist and extracting the water from it. Any of the above described preferred embodiments may be used with a solar operated evaporative assembly 200 as shown in Figure 14. The assembly 200 would include a tank 201 that would receive the dissolved desiccant to be concentrated via evaporation. A further storage tank 202 could be connected to the tank 201. As a particular example, the pump 167 could deliver the dissolved desiccant to a header tank 203 with it then flowing down a heated surface 204 for delivery to the tank 201. The surface 204 would be typically a black heat absorbing surface to heat the liquid flowing thereover to cause water to evaporate and thereby concentrate the dissolved desiccant for delivery to the tank 201. A transparent sheet (glass) 205 would aid in raising the

temperature of the surface 204. Still further if required, a fan 206 could pass air over the liquid stream to aid in evaporation with the air exiting via an outlet 207. The concentrated dissolved desiccant would then be delivered to the nozzle 159.

Typically the assembly 200 would be mounted on the roof 208 of a building 209. The assembly 200 could also be used to concentrate the desiccant when the associated air conditioning system is non operative. For example, the dissolved desiccant could be circulated from the tanks 201 and 202 to the tank 203 for continued concentration. This concentrated desiccant could then be used when the assembly 200 is no longer receiving sunlight. In Figure 15 there is schematically depicted an air conditioning apparatus 250.

In that regard the apparatus 250 may merely condition air for delivery to a room or alternatively may condition air for a refrigerator.

The apparatus 250 has an outer housing 281 providing a number of air inlets 251, 252, 253 and 254, as well as an outlet 255. Located internally of the housing 250 is a first heat exchanger 256 and a second heat exchanger 257, the heat exchangers 256 and 257 may be each a heat exchanger 10 as previously described. The heat exchanger 256 has a first path 258 and a second path 259, while the heat exchanger 257 has a first path 260 and a second path 261.

The paths 258 and 260 deliver air to a chamber 262 that is provided with a plurality of vent openings via which air is exhausted to the exterior. Air from the chamber 265 is delivered to a fan 266 at the outlet 255. From there air is delivered to the interior of a room or the interior of a refrigerator or cool room.

Upstream of the path 258 is a spray nozzle 278 that delivers a water mist to the path 258 to pass therealong with the air being delivered to the path 258. The nozzle 278 receives water under pressure from a pump 268 that takes water from the reservoir 264.

The air passing along the path 258 comes from a fan 269 that takes air from the inlet 254 and delivers it under pressure to the path 258.

Upstream of the path 260 is a nozzle 270 that receives water under pressure from the pump 268 so as to deliver a water mist to the path 260. Air passing along the path 260 comes from a fan 271 that takes air from the inlet 253 and delivers it under pressure to the path 260.

A nozzle 272 downstream of the path 261 delivers a spray mist to the path 261 in a manner that the mist passes along the path 261 in the opposite direction to the flow of

air therealong. The mist delivered via the nozzle 272 is a dissolved desiccant, delivered to the nozzle 272 by a pump 273, the pump 273 takes the dissolved desiccant from a reservoir 274.

Air from the inlet 251 enters a chamber 275 that feeds the air to the path 261. Moisture in the air passing along the path 261 further dilutes the desiccant resulting in an exothermic reaction as previously discussed. The dissolved desiccant is delivered to the chamber 275 from where it drains to an evaporation pad 276. A fan 277 causes an air stream to pass through the pad 276 to evaporate water therefrom thereby condensing the desiccant for delivery to the reservoir 274. Air passing through the pad 276 is delivered to the chamber 262 and mixes with the air from paths 258 and 260.

The pump 268 also delivers water under pressure to a nozzle 278 that sprays water for delivery to the path 258. The water in spray form cools air passing along the path 258, with the cooled air being delivered to the chamber 252. Still further, air exiting the path 261 passes through a spray suppression pad 279 for delivery to the path 259. As mentioned previously air passing along the path 261 is heated, and therefore warm air is delivered to the path 259 which aids evaporation of the water passing along the path 258 to thereby cool the air passing therealong. A further pad 280 is provided to further inhibit mist. In operation of the above described apparatus 250, cool dry air exits via the outlet 255 while return air from the interior of the room or refrigerator is delivered to the inlets 253 and 254. Exterior air is delivered to the inlets 251 and 252.

In a modification of the above described 250, part of the cold dry air exiting the outlet 265 is delivered via a duct 283 to the inlet 254. Preferably the duct 283 would include a valve that could adjustably regulate the flow rate passing along the duct 283. In a further modification between the fan 277 and pad 276 is a heater 282. In the embodiment of Figure 15, the apparatus 250 can provide dry cooled air, heated air and also provides for the harvesting of water from the outside air taken in through the inlets 251 and 252. In the above described preferred embodiments the nozzles 71, 96, 128, 160, 270 and 278 maybe "turned off. Accordingly air being delivered to the outlets 56, 86, 114 154 and 255 is heated as maybe required during winter.

A further advantage of the above described preferred embodiments is that desiccants such as lithium chloride act to sterilize the air being delivered to the outlets 56, 86, 114 and 154 from the paths 60, 91, 120, 160, 270 and 278.