WO2009027975A1

WO2009027975A1 - A system for collecting condensed dew water and a method thereof

Info

Publication number: WO2009027975A1
Application number: PCT/IL2008/001166
Authority: WO
Inventors: Haim Katzir; Patricia Katzir
Original assignee: Haim Katzir; Patricia Katzir
Priority date: 2007-08-28
Filing date: 2008-08-27
Publication date: 2009-03-05
Also published as: IL185565A0

Abstract

A system for condensing of atmospheric air water molecules, comprising: a downward slanted surface covered by water repelling material. Of special interest is a hydrophobic polymer covered with Nanostructures fabricated in a controllable manner. The surface having an elevated temperature over air temperature reaching the dew point, water droplet collecting and directing means and a storage sub-system. A substantial portion of the water droplets are condensed on said water repelling surface are gravitationally flowing down the surface and directed into the storage subsystem.

Description

A SYSTEM FOR COLLECTING CONDENSED DEW WATER AND A METHOD

THEREOF

FIELD OF THE INVENTION

The present invention generally relates to condensing dew and collecting the condensed water. The present invention particularly relates to a system and method for condensing a substantial portion of dew water molecules, accumulating and storing the water for local use.

BACKGROUND OF THE INVNETION

With increasing industrialization and population growth, world's water supplies are reaching their capacity. There is already an acute shortage of potable water in developing countries. Shortage of water is commonly linked to desert areas on the globe. For that reason, those areas are very scarcely populated. Desert areas though, are characterized by intensive dew phenomenon. The dew which is water in the form of droplets condensed from atmospheric water molecules appear on exposed objects in the night hours. Desert area weather is characterized by a sizeable day vs. night temperature differential. Consequently, exposed object surfaces which are not warmed by conducted heat from deep ground, such as: grass, leaves, railings, car roofs, and bridges cool by radiating heat, resulting that atmospheric moisture that condenses at a rate greater than that of which it can evaporate and the formation of water droplets. The temperature at which droplets can form is called the Dew Point. When surface temperature drops, eventually reaching the dew point, atmospheric water vapor condenses to form small droplets on the surface. Sufficient cooling of the surface typically takes place when a surface loses more energy by infrared radiation than it receives as solar radiation from the sun, which is especially the case on clear nights while poor thermal conductivity restricts the replacement of such losses from deeper ground layers which are typically warmer at night.

Desert inhabitants in ancient ages have realized the potential of replacing unavailable water resources with dew condensing, collecting and storing means, which have been applied quite successfully. Modern time techniques have been applied to further enhance the utilization of the dew by collecting a higher number of dew droplets from the condensing areas.

US3318107 incorporated herein by reference discloses a dew collecting method and apparatus. Water is collected at night from surrounding atmosphere by causing the temperature of a collecting surface to be lowered to or below the temperature that the dew condenses (dew point). The apparatus comprises a sheet having water-attracting (hydrophilic) surface, low radiation absorbance in the wavelength range of 0.2μm÷0.3μm and high emissivity of radiation in the range of 5μm÷30μm. The sheet is thermally isolated from a supporting surface by a layer of air being between the sheet and the supporting structure. The apparatus further includes means for collecting accumulated dew on its hydrophilic surface and an inflatable rig structure for carrying the sheet.

US6,644,060 incorporated herein by reference, discloses a an apparatus for extracting potable water from the environment air comprises a moisture collecting system having dew-forming surfaces and disposed so that the air drawn into the apparatus passes there through and moisture from the air condenses in the dew-forming surfaces. The apparatus also comprises a water reservoir capable of receiving water collected as moisture in the moisture collecting system. The water reservoir has a bottom and a side surface constituting a surface of revolution around a longitudinal axis of the reservoir, the reservoir having an outlet port formed at the bottom thereof along the longitudinal axis, for the withdrawal of water from the reservoir, and a circulation inlet port formed in the side surface. The circulation inlet port is designed so as to enable the introduction of water into the reservoir tangentially to the surface. The apparatus further comprises a water circulation line extending from the outlet port to the circulation inlet port of the water reservoir through a water filtration and sterilization system to provide the circulation of water through the reservoir by means of a pumping device, and a water dispensing valve for the external dispensing of water from the circulation water line.

US5201192 incorporated herein by. reference, discloses a water droplet collector for collecting drops of dew condensed from the air onto cool surfaces in a high humid compartment such as a cooling storage cabinet formed to store perishable fresh foodstuffs therein. The water droplet collector is composed of a perforated thin plate and a base plate detachably overlapped with the perforated thin plate in such a manner as to form a .capillary clearance for attraction of drops of dew condensed on the perforated thin plate. Both the plates are detachably mounted within the high humid compartment in such a manner that the base plate is arranged to receive drops of dew falling from a ceiling of the compartment.

Archeological discoveries of ancient desert settlements, as well as recent experimentation with dew collection systems, point out a potential for substantial water quantities obtainable by large scale systems operable for condensing dew droplets, collecting the condensed droplets and storing the water. Hence there is still a long felt need in water short supply desert areas, for providing inexpensive and sufficient supply of water by utilizing air moisture and special weather conditions.

SUMMARY OF THE INVENTION

It is the object of the present invention to disclose a system for condensing of atmospheric air water, comprising: a downward slanted surface covered by a water repelling material. The surface is having an elevated temperature over ambient temperature reaching about the dew point, water droplet collecting and directing channels and pipes and a water storage subsystem. The system is adapted to condensing a substantial portion of the water droplets on the water repelling surface and gravitationally having said droplet flow down said surface and directed into said water storage subsystem.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the water repelling material is a super- hydrophobic polymer having nanometer size particles across said entire surface area.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the water repelling material is selected from a group consisting of Teflon and siloxanes or any combination thereof.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the color of said water repelling material is selectable for providing maximum heat absorption by said water repelling surface.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the shape of the water repelling surface is selected from a group consisting of planar slanted surface, curved slanted surface or any combination thereof.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, further comprising hot air pipes for heating the condensation surface to reach the dew point.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the hot air is heated by energy sources selected from a group consisting of waste, manure, coal, gas fuel, engines solar energy or any combination thereof. Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the storage subsystem is feeding an agricultural irrigation system by a water pump.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the system which is located adjacent to a greenhouse, wherein the greenhouse is adapted to generate water droplets by being covered with a water repelling material.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein a practical area size of said system is capable of providing a fair amount of water supply required by an agricultural irrigation system.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein a home roof is covered with the water repelling surface and the water flowing down the roof is collected by said home gutters and directed into a water storage subsystem.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the water in the storage subsystem is treated and supplied as potable water to the home.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, wherein the roof and walls of an average home can provide a substantial amount of an average home water supply requirement.

Another object of the present invention and any of the above is to disclose a system for condensing atmospheric air water, comprising an infrastructure of water collecting and storage subsystem adjacent to objects selected from a group consisting of tractors, machines, vehicles and air conditioning units covered with said water repelling material.

It is the object of the present invention to disclose a method for condensing of atmospheric air water, comprising: obtaining a system a water repelling downward slanted surface. The surface having an elevated temperature over air temperature reaching about the dew point, a water droplet collecting channels and pipes and a storage sub-system, condensing said air water into air droplets, collecting said water droplets flowing gravitationally down said water repelling surface into a water storage tank. The method is particularly utilizing distinct weather conditions for providing substantial quantity of water. BRIEF DESCRIPTION OF THE DRAWING AND FIGURES

In order to understand the invention and to see how it may be implemented in practice, a plurality of preferred embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawing, in which

Fig. 1 illustrates a non scaled dimensionally, isometric view schematic of a dew collecting structure, according to an embodiment of the present invention;

Fig. 2 illustrates a non scaled dimensionally, isometric view schematic of an agricultural dew collecting system connected to the water supply system, according to. an embodiment of the present invention;

Fig. 3 illustrates a non scaled dimensionally, isometric view schematic of an agricultural dew collecting structure combined with the structure of a greenhouse, according to the present invention; and

Fig. 4 illustrates a--non~scaled dimensionally house water supply system schematic whereas the rooftop is used as a dew collecting surface, according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, will remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide an

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, those skilled in the art will understand that such embodiments may be practiced without these specific details. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment or invention. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. The drawings set forth the preferred embodiments of the present invention. The embodiments of the invention disclosed herein are the best modes contemplated by the inventors for carrying out their invention in a commercial environment, although it should be understood that various modifications can be accomplished within the parameters of the present invention.

The term 'Nanotechnology' refers in a non limited manner broadly to a field of applied science and technology controlling of matter on a scale smaller than normally 1 to 100 nanometers, and the fabrication of devices within that size range.

The term 'super-hydrophobic polymer' refers hereinafter in a non limited manner to a polymer having a nanostructure surface. A novel application of the nanostructures is to reduce friction in liquid flow in micro-fluidic systems. After a hydrophobic surface treatment, the sharp-tip nanostructures make the surface super-hydrophobic, levitating liquid over air pockets trapped between the non-wetting nanostructures on the surface. Then the liquid is in minimal contact with the solid surface, and expected to flow with significantly reduced 'skin friction.

The term 'grafting molecules' refers hereinafter in a non limited manner to a method of planting molecules into a material made of different molecules to fuse the crafting molecules into the material.

The term 'water repelling material' refers hereinafter in a non limited manner to a material that does not absorb water.

The term 'dew point' refers hereinafter in a non limited manner to of a given parcel of air is the temperature to which the parcel must be cooled or heated, at constant barometric pressure, for water vapor to condense into water.

The term 'siloxanes' refers hereinafter in a non limited manner to a class of organosilicon compounds with the empirical formula R₂SiO, where R is an organic group. These compounds can be viewed as a hybrid of both organic and inorganic chemical compounds.

The high efficiency of the dew collecting system is attributed to a large extent to the material used on the droplet generation and surface: a super-hydrophobic polymer. A new chemical manufacturing technology, which is still evolving, yields nanostructure polymer surfaces in a controllable manner. The nanostructure surfaces are fabricated by combining self-assembly of surface grafting molecules with mechanical manipulation of the grafting points in the underlying elastic surface. These surfaces have superior non- wetting and barrier properties in that they are super-hydrophobic and non-permeable. The material characteristics do not deteriorate even after prolonged exposure to water. The contact angle of water on such flat solids is typically of the order of 100° to 120°, but reaches values as high as 160° to 175° if they are rough or micro-textured. This result cannot be generated by surface chemistry alone. On one hand roughness increases the surface .area of the. solid, which geometrically enhances hydrophobicity. On the other hand, air can remain trapped below the drop, which also leads to a super-hydrophobic behavior, because the drop sits partially on air. The material is versatile in terms of color, inexpensive and effortlessly applicable on many materials, hence it is well matched to applications requiring water repelling surfaces including dew generation collection. Water quantity of dew collection calculated from preliminary experiments conducted in the Negev Desert, show that a reasonable size of dew collection area provides the water supply needed for an average agricultural land unit in the desert. A dew collection system is preferably installed in the field. The collected dew water flows gravitationally to be stored in a tank system which is connected to the field irrigation system via a substantially low power water pump.

Reference is now made to Fig. 1 which is a basic dew collecting device 10 mounted on the ground 100. The collecting structure 10 is made of a material selected from a group consisting of, metal, wood, plastic, soil, rocks or any combination thereof. The shape of the device structure surfaces is selected form a group consisting of planar shape surface, curved shape surface or any combination thereof, so that any of the device surfaces is slanted for enabling a continuous gravitational water flow from any surface portion into the storage tank. The surfaces of the device are further covered with water repelling material 11 selected from a group consisting of: super-hydrophobic polymers, Teflon, and siloxanes or any combination thereof accommodating water flowing across the surface by the gravitational force. An optional horizontal hot air pipe 12 and several vertical pipes 13a, 13b and 13c connected to the horizontal pipe at one end and connected to the warm ground at the other end, are added to the device for warming the surfaces of the device and maintaining a temperature differential between the air atmosphere. When water molecules in the air contact the warmer surface the air reaches the dew point and the water molecules are condensing into water droplets. The water droplets are not absorbed by the water repelling surface and hence flow down the surface. Hot air flowing in the hot air pipe 12 is a product of wood or weed burning available in the field. Other sources of energy selected from a group consisting of waste, manure, coal, gas fuel, solar energy, engine heat or any combination thereof can be used for warming the device surfaces. A black surface material used as well as good isolation between the device and the ground are other contributing factors for maintaining a dew point temperature on the device surface.

Reference is now made to Fig. 2 which an agricultural water supply system made of dew collection water. System 20 comprises five dew collection devices 21a, 21b, 21c, 21d and 21e. Five water tanks 22a, 22b, 22c, 22'd, 22e disposed in the ground are each collecting the water flowing down the surfaces of the corresponding dew collecting devices. The water flowing downward is collected by a channels and pipes directing the water flow of each collecting device into the corresponding water storage tank. The separate water storage tanks are connected via water pipe 23 for effectively forming a common storage tank. The common water pipe is further connected to a water pump 23 and the outlet of the water pump is feeding the irrigation system. The system is placed in the field where it is being used so that the system provides a water resource directly where the water is needed. Effective dew collecting device operation requires that the surface temperature of the device should be about 15⁰C higher than the temperature of the surrounding. The rate of condensing depends on the air humidity.

The rate of condensing and collecting water from the system ranges between a minimum level of 20cc of water per minute per Im and a maximum level of lOOcc.of water per minute per Im². Assuming six nightly hours of water generation and 250 nights per year of water generation, a dew collecting device generates water quantity of: 2.25m³ ÷ 9m³.

Agriculture requires an average 1400 m of water per 1000 m agricultural area. Considering an average medium range of water supply of 5m³ of water per year in the long run, for each 1000 m² of agriculture are, the total collecting area of the system is: 1400/5=280 m².

In other words: The collecting area of the system has to be 25% of the agricultural area for full water supply for irrigation. Considering the inexpensive materials of the system, the many years of free water supply and minimal system maintenance, and the alternative of bringing water remotely to desert areas the system provides quite a practical solution to problem of shortage of water.

Reference is now made to'Fig. 3~which fs'another embodiment of the present invention which encompasses the water generating surface with the agricultural area. System 30 is combined from a dedicated water generating device 31 and a greenhouse 32. The greenhouse is covered by the same water repelling surface as the device while the shape of the greenhouse cover is adaptable to generating flowing water. Hence the greenhouse cover is also used as a water generating device. Water from device 31 is flowing into storage tank 33a and water from the green house 32 cover is flowing into storage tank 33b. A dual functioning greenhouse cover saves agricultural area and expenses required for a dedicated device while increasing substantially water generation. The entire system excluding the water storage tanks are constructed on ground level 100.

It is an integral 'core aspect of the invention to provide a system and method for condensing atmospheric air water (dew) on roofs and surfaces of greenhouses, dwellings, shelters, animal shelters, storage shelters, barns, erected covers, which are at least partially coated with the aforementioned hydrophobic material.lt is an integral core aspect of the invention that the roofs surfaces and walls of the the aforementioned greenhouses, dwellings, shelters, animal shelters, storage shelters, engine rooms, barns, and erected covers enclose volumes in which humans, animals, plants, agricultural or horticultural growths or products or any devices and engines emit heat energy.lt is a further aspect of the invention that water condensed and collected in this way is used for agricultural uses or as drinkingwater.

Reference is now made to Fig. 4 which is an embodiment of the system adapted as a house water supply system. System 40 is the house combined with the system. The slanted roof of the house 42 as well as house walls 41 are covered with the water repelling material. Water generated during the night, is flowing through the house gutters through water pipe 43 a into storage tank 46a and through water pipe 43b into storage tank 46b. Water pipe 47 connects the distinct storage tanks into a common storage tank system. Water from the storage tank system is fed into a water treatment system 45, supplying potable water to the house through pipe 44. Being on top of a home assures that the temperature difference between the outdoor air and the water collection surface is effortlessly maintained.

The overall water supply of a house is based on the assumptions of water generation in the preceding section of an average of 5m³ water per year per m². The collecting area of an average home is 170m. Thus the overall average water supply of a house including water for gardening amounts to: 170x5=850 m³. An average water supply requirement is 1400m³ water per year. Hence the system provides about 60% of the requirement. Slanted roofs of other agriculture buildings like goat shed, cow shed and barn can be used as surface of water generation systems as well. There are other outdoor of curved shaped objects utilizable during nights for condensing water molecules, collecting and storing water. Machines, tractors, vehicles, air-conditioning units can have typically higher temperatures than the air and provide dew point temperature to the water molecules content in the air. The generated water is usable by covering the surfaces of the objects with the water repelling material used for the dedicated device and providing on the ground an infrastructure for collecting and storing the water and making the water flow into a central storage tank system. Using surfaces of functioning structures as water collecting areas can be particularly valuable to water generation»system for the obvious reasons of area saving and building structure saving.

It will be appreciated that the above described methods may be varied in many ways including, changing the order of steps, and/or performing a plurality of steps concurrently.

It should also be appreciated that the above described description of methods and apparatus are to be interpreted as including apparatus for carrying out the methods, and methods of using the apparatus, and computer software for implementing the various automated control methods on a general purpose or specialized computer system, of any type as well known to a person or ordinary skill, and which need not be described in detail herein for enabling a person of ordinary skill to practice the invention, since such a person is well versed in industrial and control computers, their programming, and integration into an operating system.

For the main embodiments of the invention, the particular selection of type and model is not critical, though where specifically identified, this may be relevant. The present invention has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. No limitation, in general, or by way of words such as "may", "should", "preferably", "must", or other term denoting a degree of importance or motivation, should be considered as a limitation on the scope of the claims or their equivalents unless expressly present in such claim as a literal limitation on its scope. It should be understood that features and steps described with respect to one embodiment may be used with other embodiments and that not all embodiments of the invention have all of the features and/or steps shown in a particular figure or described with respect to one of the embodiments. That is, the disclosure should be considered complete from combinatorial point of view, with each embodiment of each element considered disclosed in conjunction with each other embodiment of each element (and indeed in various combinations of compatible implementations of variations in the same element). Variations of embodiments described will occur to persons of the art. Furthermore, the terms "comprise," "include," "have" and their conjugates, shall mean, when used in the claims, "including but not necessarily limited to." Each element present in the claims in the singular shall mean one or more element as claimed, and when an option is provided for one or more of a group, it shall be interpreted to mean that the claim requires only one member selected from the various options, and shall not require one of each option. The abstract shall not be interpreted as limiting on the scope of the application or claims.

It is noted that some of the above described embodiments may describe the best mode contemplated by the inventors and therefore may include structure, acts or details of structures and acts that may not be essential to the invention and which are described as^' examples. Structure and acts described herein are replaceable by equivalents which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the invention is limited only by the elements and limitations as used in the claims.

Claims

1. A system for condensing of atmospheric air water, comprising:

(i) a downward slanted surface covered by a water repelling material; said surface having an elevated temperature over ambient temperature reaching about the dew point;

(ii) water droplet collecting and directing channels and pipes; and (iii) a water storage sub-system; wherein said system is adapted to condensing a substantial portion of said water droplets on said water repelling surface and gravitationally having said droplet flow down said surface and directed into said water storage subsystem.

2. The condensing system according to claim 1, wherein said water repelling material is a super-hydrophobic polymer having nanometer size particles across said entire surface area.

3. The condensing system according to claim 1, wherein said water repelling material is selected from a group consisting of Teflon and siloxanes or any combination thereof.

4. The condensing system according to claim 1, wherein the color of said water repelling material is selectable for providing maximum heat absorption by said water repelling surface.

5. The condensing system according to claim 1, wherein the shape of said water repelling surface is selected from a group consisting of planar slanted surface, curved slanted surface or any combination thereof.

6. The condensing system according to claim I₅ further comprising hot air pipes for heating said condensation surface to reach the dew point.

7. The condensing system according to claim 8, wherein said hot air is heated by energy sources selected from a group consisting of waste, manure, coal, gas fuel, engine, solar energy or any combination thereof.

8. The condensing system according to claim I₅ wherein said storage subsystem is feeding an agricultural irrigation system by a water pump.

9. The condensing system according to claim I₃ wherein said system which is located adjacent to a greenhouse, wherein said greenhouse is adapted to generate water droplets by being covered with a water repelling material.

10. The condensing system according to claim 1 , wherein a practical area size of said system is capable of providing a fair amount of water supply required by an agricultural irrigation system.

11. The condensing system according to claim I₅ wherein a home roof is covered with said water repelling surface and said water flowing down the roof is collected by said home gutters and directed into a water storage subsystem.

12. The condensing system according to any of claims 1 or 11, wherein said water in said storage subsystem is treated and supplied as potable water to said home.

13. The condensing system according to claim 11 , wherein said roof and walls of an average home provides a substantial amount of an average home water supply requirement.

14. The condensing system according to claim 11 wherein said said water repelling surface is on a roof or surface selected from a group consisting of roofs or surfaces of greenhouses, dwellings, shelters, animal shelters, storage shelters, and erected covers enclosing volumes in which humans, animals, plants, agricultural or horticultural growths or products or any devices and engines emit heat energy.

15. The condensing system according to claim I₅ comprising an infrastructure of water collecting and storage subsystem adjacent to objects selected from a group consisting of tractors, machines, vehicles and air conditioning units covered with said water repelling material.

16. A method for condensing of atmospheric air water, comprising:

(i) obtaining a system a water repelling downward slanted surface; said surface having an elevated temperature over air temperature reaching about the dew point, a water droplet collecting and directing channels and pipes and a storage sub-system;

(ii) condensing said air water into air droplets;

(iii) collecting said water droplets flowing gravitationally down said water repelling surface into a water storage tank; wherein said method is particularly utilizing distinct weather conditions for providing substantial quantity of water.