Method and device for obtaining water from ambient air

Abstract

A method for obtaining water from ambient air is disclosed that includes bringing the ambient air into contact with at least one liquid absorption agent for absorbing at least one part of the water contained in the ambient air, conveying an absorption agent diluted by the absorbed water to a first heat exchanger, and transferring the diluted absorption agent in at least one desorption device. Water desorbed in the desorption device is transported to the first heat exchanger, the desorbed water being cooled by means of the diluted absorption agent by means of the first heat exchanger. A device for obtaining water from ambient air is also disclosed.

Claims

1. A device for obtaining water from ambient air comprising: at least one device configured for at least one of applying a liquid absorption agent onto a first absorption structure and conducting the liquid absorption agent to the first absorption structure, wherein the first absorption structure is formed for absorbing at least a part of the water contained in the ambient air; at least one conveying device for conveying an absorption agent diluted by the absorbed water to a first heat exchanger; and at least one desorption device, wherein the first heat exchanger is connected to the desorption device in a liquid conducting manner such that water desorbed in the desorption device is cooled by means of the diluted absorption agent, wherein at least one evaporation structure is formed in the desorption device, and wherein at least a part of the water of a heated and diluted absorption agent supplied to the desorption device evaporates at and in the evaporation structure, or at least a part of the water of a heated and diluted absorption agent supplied to the desorption device evaporates at or in the evaporation structure, wherein at least one condensation structure soaked with water for condensation of the water evaporated by means of the evaporation structure is formed in the desorption device, and wherein the device includes at least one line system, wherein the line system is formed such that the at least one condensation structure is at least partially soaked with desorbed water cooled by the first heat exchanger.

2. The device according to claim 1, wherein the liquid absorption agent is a hygroscopic saline.

3. The device according to claim 1, wherein the desorption device includes means for transporting the water evaporated by means of the evaporation structure to the condensation structure.

4. The device according to claim 1, wherein the device includes means for generating a negative pressure in the desorption device.

5. The device according to claim 1, wherein the device includes at least one device for removing the desorbed water from a system circuit.

6. The device according to claim 1, wherein the line system is formed such that concentrated absorption agent flowing off from the desorption device is supplied to the first absorption structure with or without interposition of a third heat exchanger.

7. The device according to claim 6, wherein the third heat exchanger is arranged after the first heat exchanger in a flow direction of the diluted absorption agent, wherein heating of the diluted absorption agent is effected by the third heat exchanger before entry into the desorption device.

8. The device according to claim 1, wherein the device includes at least one heating device for heating the diluted absorption agent, and wherein the heating device(s) is/are arranged before, after, outside of, or within the desorption device.

9. The device according to claim 8, wherein the heating device includes at least one second heat exchanger arranged between the first heat exchanger and the desorption device, and wherein the second heat exchanger is connected to the first heat exchanger in a liquid conducting manner on the one hand and to the desorption device in a liquid conducting manner on the other hand.

10. The device according to claim 9, wherein the heating device(s) include(s) heat exchangers, solar modules or line systems for heat transfer liquids.

11. The device according to claim 9, wherein the heating devices include at least one of a heat exchanger, a solar module and a line system for heat transfer liquids.

12. The device according to claim 9, wherein the second heat exchanger is in operative connection to at least one heating device.

13. The device according to claim 9, wherein the at least one heating device in operative connection to the second heat exchanger includes at least one solar module and at least one hose system with a heat transfer liquid.

14. The device according to claim 12, wherein the at least one heating device in operative connection to the second heat exchanger includes at least one solar module or at least one hose system with a heat transfer liquid.

Description

(1) Therein, the FIGURE shows a schematic representation of a device according to the invention.

(2) The device 10 for obtaining water from ambient air 14 includes a device (not illustrated) for spreading a liquid absorption agent 16 to an absorption structure 12 in the illustrated embodiment. For spreading or applying the liquid absorption agent 16, a suitable pipe system with corresponding openings or valves or comparable spraying devices can be used. Therein, the liquid absorption agent 16 is in particular distributed over an entire upper surface of the absorption structure 12 and thus soaks the absorption structure 12. Subsequently, the absorption agent 16 slowly flows into the lower areas of the absorption structure 12, where it again flows out of it and is again collected by a suitable tub system (not illustrated). One recognizes that the absorption structure 12 is honeycombed formed in the illustrated embodiment. Thereby, a very large surface arises, on which an absorption of at least a part of the water contained in the ambient air 14 can be effected. Therein, the absorption of the water from the ambient air 14 is effected in the liquid absorption agent 16, wherein the condensation heat arising thereby is immediately again released to the ambient air 14 from the absorption agent 16 by the large surface of the honeycombed absorption structure 12. By the absorption of water from the ambient air 14, the liquid absorption agent 16 is diluted and exits the absorption structure 12 as a diluted absorption agent 18.

(3) In the illustrated embodiment, the ambient air 14 is brought into contact with the liquid absorption agent 16 in large-surface manner. The liquid absorption agent 16 is for example a concentrated lithium chloride solution. Therein, the absorption structure 12 can be formed such that it can be set up outdoors and can be passed by natural wind. Thereby, energy and plant cost can be saved since additional blowers are not required. However, if the natural wind conditions should not allow sufficiently large passage of the ambient air 14 through the absorption structure 12, corresponding auxiliary means such as for example blowers can of course be additionally employed. The absorption structure 12 is to be selected with suitable permeability, suitable strength and suitable size. Such structures are for example very inexpensively available in a robust cardboard design protected against decomposition and are for example nowadays used in the evaporative cooling of henhouses.

(4) In the further description of the embodiment, the straight lines provided with arrows represent liquid lines such as for example pipes or hoses, in which the liquids used in the device flow in arrow direction. The pumping devices required thereto are known to the expert and illustrated only in one design variant in the FIGURE.

(5) They are the conveying device or the pump 48 for conveying the absorption agent 18 diluted by the absorbed water to a first heat exchanger 20. One recognizes that the first heat exchanger 20 is connected to a desorption device 30 via a line system 54 in liquid conducting manner such that water 42 desorbed in the desorption device 30 is cooled by means of the diluted absorption agent 18. In addition, first heating of the diluted absorption agent 18 is effected via the first heat exchanger 20 since the desorbed water 42 coming from the desorption device 30 has a higher temperature than the diluted absorption agent 18.

(6) In the illustrated embodiment, the diluted absorption agent 18 is supplied to a further heat exchanger 24 after the first heat exchanger 20. The heat exchanger 24 serves for heat recovery of the heat of a concentrated absorption agent 38, which is returned or supplied from the desorption device 30 to the heat exchanger 24 via a line system 52. Therein, the concentrated absorption agent 38 has a higher temperature than the diluted absorption agent 18 coming from the first heat exchanger 20. The concentrated absorption agent 38 flowing off from the desorption device 30 is then again supplied to the upper area of the absorption structure 12 after the heat exchanger 24 in flow direction. This is again effected via the line system 52.

(7) In the further course, the diluted absorption agent 18 is supplied to a second heat exchanger 22, where it is heated by a heat transfer liquid of a heating device, namely a solar module 26 and a corresponding hose system 28 of the solar module 26. The now thus heated liquid absorption agent 36 is then starting from the second heat exchanger 22 transferred into a housing 46 of the desorption device 30 via a line system 56. One recognizes that the heated, diluted absorption agent 36 is supplied to an evaporation structure 32, which is formed within the desorption device 30, and soaks it. The evaporation structure 32 is again honeycombed formed. A part of the heated, diluted absorption agent 36 evaporates with formation of water vapor at the evaporation structure 32. The water vapor, which is released by the heated, diluted absorption agent 36, is carried along by a regeneration airflow 40 and subsequently brought into contact with a condensation structure 34 soaked with water within the housing 46. The condensation structure 34 serves for condensing the water evaporated with the aid of the evaporation structure 32. One recognizes that the condensation structure 34 is also honeycombed formed to form a surface as large as possible. In an advantageous configuration of the desorption device 30, the evaporation structure 32 and the condensation structure 34 are spatially arranged very close to each other, for example parallel to each other, whereby the transport of the water vapor can occur via the regeneration airflow 40 from the evaporation structure 32 to the condensation structure 34 for example by natural diffusion and/or natural convection. Thus, an additional blower can optionally be omitted, which entails savings in the electricity consumption and in the plant cost. The regeneration air 40 always remains completely within the housing 46. Therein, the temperature of the heated, diluted saline 36 is to be selected such that the partial pressure of the water vapor in the regeneration air 40 exceeds the saturation pressure at ambient temperature.

(8) Since the water, with which the condensation structure 34 is soaked, has a temperature slightly above the ambient temperature and thus a considerably lower temperature than the heated, diluted saline 36, the water vapor condensates from the regeneration air 40 within the condensation structure 34 and thus serves for obtaining water from the ambient air 14. One recognizes that the heat again released in the condensation of the water vapor is transferred out of the condensation structure 34 via the desorbed water 42 and delivered to the diluted absorption agent 18 by means of the first heat exchanger 20. Thereby, a large and expensive air/air heat exchanger can be omitted. Additional cooling devices or for example blowers for cooling can also be omitted, which again entails savings in the electricity consumption and in the plant cost.

(9) Furthermore, one recognizes that the absorption agent 38 again concentrated by the partial evaporation of the water on the evaporation structure 32 is discharged out of the housing 46 of the desorption device 30 via the line system 52 and is again delivered to the absorption structure 12 via the third heat exchanger 24. Thus, the process cycle can be readily repeated.

(10) Furthermore, it becomes clear from the FIGURE that at least a part of the desorbed water 42 is again delivered to an upper area of the condensation structure 34 in the desorption device 30 via a line system 50 according to the illustrated embodiment. Since the desorbed water 42 has been cooled by the first heat exchanger 20, this cooled desorbed water is denoted by 44.

(11) In the above description of the embodiment, for the sake of convenience, it is represented such that the complete mass flow of the absorption agent 16, 18, 36, 38 or of the water flows through the complete circuit. The system can be thus operated and will achieve the represented result. However, it is clear to an expert that possibly for optimizing the heat flows and depending on absorption rates and evaporation rates, not the complete mass flow, but only a part of the absorption agent 16, 18, 36, 38 or of the water has to flow through the complete circuit. Another part of the absorption agent 16, 18 can be conveyed for example from the lower to the upper area of the absorption structure 12 by means of a separate pump. Similarly, a part of the heated, diluted absorption agent 36 can be conveyed from a lower to an upper area of the evaporation structure 32 and therein possibly partially flow through the second heat exchanger 22 for absorbing further heat. And a part of the desorbed water 42 can be conveyed from a lower to an upper area of the condensation structure 34. All of the above mentioned mass flows or partial flows can also at least partially be passed past the second and/or third heat exchanger 22, 24 instead of through them. The volume flows of the cold and the warm absorption agent, respectively, (e.g. by suitable pumping powers) and the volume flows of the airflows (e.g. by a suitable permeability of the honeycomb structures) can also be adapted. The present invention explicitly includes such possible combinations and variants for optimizing the overall system with regard to the yield of water and/or to the energy consumption and/or to the plant cost.

(12) In order to produce drinking water from the desorbed water 42, a filter and disinfection process and a mineralization process, respectively, optionally also have to be installed downstream. These processes correspond to the prior art. It is pointed out that the concentrated absorption agents and salines, respectively, proposed in the present invention already have a highly disinfecting effect. For the sake of convenience, the mineralization of the water obtained from the air could occur in that the water is passed through a gravel bed.

(13) In the following, further embodiments of the device 10 for obtaining water from the ambient air 14 not shown in the FIGURE are described.

(14) Therein, the heated, diluted absorption agent 36 can for example be again heated multiple times within or outside of the desorption device 30 in that it is again passed through one or more heat exchangers after it has flown over/through the evaporation structure 32. The heat exchanger(s) can be arranged within or outside of the housing 46 of the desorption device 30. One/multiple elements for heating the absorption agent 36 can also be attached within the housing 46, which are for example passed by the heat transfer liquid of the solar modules 26. The evaporation process can thus be greatly assisted. In a further exemplary embodiment, the elements for heating the absorption agent 36 can be large-surface configured such that the absorption agent 36, which flows over these elements, immediately evaporates on the surface thereof.

(15) Furthermore, there is the possibility that a reduced pressure exists within the housing 46 of the desorption device 30 in that the air is completely or partially removed. This can for example be achieved by means of a vacuum pump or also in that the water within the housing 46 is brought to the boil by heating by an additional heating element and the water vapor can exit the housing 46 via a valve. Therein, the air contained in the housing 46 is carried along by the water vapor through the valve and removed from the housing 46. When the heating element is turned off thereupon, the water in the housing 46 again cools down and only the vapor pressure of the water vapor exists within the housing 46 thereafter. By the reduced pressure, the transport of water vapor from the evaporation structure 32 to the condensation structure 34 can now be greatly accelerated. If the gas within the housing 46 contains (almost) no air, but only water vapor, a diffusion or convection is no longer required, but the water vapor can directly flow from the evaporation structure 32 to the condensation structure 34.

(16) At this place, it is to be clarified that the term “water vapor” describes the gaseous aggregate state of water and not a mixture of air and water droplets.