Atmospheric aerosol coalescer

Abstract

An atmospheric aerosol coalescer (AAC) is a device for collecting water from cooling tower plumes, fog, and clouds. The AAC may include tapered spiral tube body with a helix shaped skin for atmospheric aerosol to pass through. Micro-droplets of water in air, as in cooling tower plumes, fog, and / or clouds separate inside the AAC due to large density difference and centrifugal forces inside the spiral tube. 3-100-micron diameter water micro-droplets may grow to 1000-4000 micron drops by coalescence on the internal walls of the AAC. Big drops detach to a drain at its base and fall through a spout to a collection pond. A number of AAC arrays may be supported by a net or an inflated pad. The net or inflated pad may be lifted by a tethered aerostat.

Description

ATMOSPHERIC AEROSOL COALESCERBACKGROUND

[0001] The technical field of the disclosed embodiments relate to atmospheric aerosol coalescence devices. More particularly, the disclosed embodiments relate to coalescing micro-droplets of water from cooling tower plumes, fog, and clouds to form large drops of water that fall by gravity.SUMMARY

[0002] Disclosed are various embodiments of an atmospheric aerosol coalescer. It is a light tapered spiral tube section open on both ends. It produces a helix path for gas carrying aerosols. It coalesces fog and cloud water micro-droplets, carried in the atmospheric gas stream passing through it, to large drops that slide to its base then fall to the ground by gravity for collection.

[0003] Fog and cloud liquid micro-droplets suspended in moving air separate and impinge on the coalescer internal surface due to centrifugal forces and surface tension. The micro-droplets grow by coalescence to big drops that fall for collection and use.

[0004] The coalescer may be made from a relatively light and inexpensive strong, UV- treated semi-rigid material. A number of coalescer devices, or “coalesces”, may be deployed extensively and supported by a net or other substrate in the open atmosphere. A tethered aerostat provides lift for higher liquid water content. Large surface area and higher collection efficiency provide commercial quantities of water from fog and clouds.

[0005] In an embodiment, the coalescer may be an atmospheric aerosol coalescer (AAC) having a body with a spiral shape and including an interior surface, a front end, and a rear end. The AAC may include a liquid drain and a drain spout. The AAC may be constructed from a UV treated plastic, and the interior surface including a hydrophobic material.

[0006] In an embodiment, the body has a helical shape. The front end of the body may have a diameter between 1 and 20 centimeters, and may be larger or the same size as the rear end. The AAC may have a mass of about 8 grams or less.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective front-side view of an atmospheric aerosol coalescer according to an embodiment.

[0008] FIG. 2 is a perspective back- side view of the atmospheric aerosol coalescer according to an embodiment.

[0010] FIG. 3 is a perspective view of an atmospheric aerosol coalescer array supported by a net according to an embodiment.

[0011] FIG. 4 is a perspective of a vertically deployed aerostat net in open atmosphere carrying a number of atmospheric aerosol coalescers according to an embodiment.

[0012] FIG. 5 is a perspective view of an inflated pad deploying atmospheric aerosol collectors in inflated pad cavities forming an array for high elevation fog / cloud water collection according to an embodiment.

[0013] FIG. 6 is side view of an atmospheric aerosol coalescer plugged into an inflated pad cavity according to an embodiment.

[0014] FIG. 7 is a flowchart describing a method for collecting water from an aerosolcontaining atmosphere according to an embodiment

[0015] FIG. 8 is a side view of an AAC water collection arrangement for cooling towers according to an embodiment.

[0016] FIG. 9 A is a partial sectional view of the AAC according to an embodiment.

[0017] FIG. 9B is an elevation view showing the angle of the spiral in the AAC according to an embodiment.

[0018] FIG. 10 shows a hook-like element on an edge of the spiral according to an embodiment.

[0019] FIG. 11 is a perspective view of an inflated pad including apertures for accepting AACs according to an embodiment.DETAILED DESCRIPTION

[0020] FIG. 1 shows a perspective front-side view of an atmospheric aerosol coalescer (AAC) 10. AAC 10 is a device for coalescing liquid micro-droplets of about 3-100-micron diameter into large drops of about 1000-4000-micron diameter.

[0021] AAC 10 may have a spiral flute shape. Aerosol-laden gas may enter AAC 10 through entry 12. Atmospheric gas passing through AAC 10 is stripped of its liquid aerosol and exit through exit 14. Liquid drain 22 is located at the helix base 28 of AAC 10. AAC 10 front frame 16 may have a square shape and have a fastener receptor 18 to attach adjacent AAC 10 together. AAC 10 has a very thin helix skin 20 that forms AAC 10 corrugated flute tube 24. Corrugated flute tube 24 has helix ridge 26 and helix base 28. AAC 10 liquid drain 22 is sloped down outwardly relative to gas flow to discharge its coalesced liquid through drain spout 30.

[0022] In an embodiment, the AAC 10 receives atmospheric aerosol-laden gas through its front entry 12. Helix skin 20 of the spiral flute tube 24 forces the aerosol laden gas to spiral inside it. Centrifugal forces created by the helix 12 shape propel aerosol particles to separate from the gas and impinge on the inner skin of the spiral flute 24. In the case of cooling tower plumes, fog and clouds, the aerosol is micro-droplets of water having a density many times greater than that of the air in the open atmosphere. The micro-droplets adhere to the inner surface of spiral flute tube 24 due to surface tension and grow by coalescence to larger drops. When the force of gravity acting on the large drop exceeds the force of surface tension, large drops detach from helix skin 20 and slide down helix base 28 to liquid drain 22. The inside surface of liquid drain 22 may be hydrophobic to maintain spherical shape of large drops, minimize their contact with liquid drain 22 surface, and speed up their discharge through drain spout 30. AAC 10 is tilted downward toward backexit 14. Liquid drain 22 discharges collected liquid through drain spout 30 to the open atmosphere to be collected in a ground lined pond.

[0023] A AC 10 may be made from a light but strong material that can withstand an open environment and exposure to strong sunlight and heat, strong winds, frequent deployment, and retrieval. Examples of materials that may be used in the manufacture of the AAC 10 include semi-rigid plastics such as, polyethylene terephthalate (PET), polyethylene (PE), nylon, polypropylene, polyurethane, polytetrafluoroethylene (PTFE), graphene, and similar materials. The materials may be ultraviolet (UV) treated.

[0024] The coalescer material should be about 8-gram or less per AAC 10 to increase surface area, produce commercial yield, and not exceed the payload limit of the aerostat. AAC 10 may be manufactured using standard plastic processes like thermoforming and blow molding.

[0025] In an embodiment, AAC 10 arrays may be produced in a one square meter mold to produce one hundred coalescers, or two-by-two meters for a yield of four hundred, or more to decreases production, assembly, and installation costs. A number of AACs 10 could be attached to nets of desired size, weight and pull strength. Such nets may be suspended from the aerostat and facing aerosol flow to coalesce aerosols. The internal surface of liquid drain 22 is preferably made hydrophobic to enhance the spherical shape of the large aerosol drops and speed their discharge to the open atmosphere for collection in a pond or on the ground.

[0026] FIG. 2 is a back-side view 32 of the AAC 10. Liquid drain 22 is shown along the length of helix base 28. Liquid drain 22 terminates in drain spout 30 where its collected water is discharged to the atmosphere and fall by gravity for collection in a pond on the ground.

[0027] The AAC 10 front entry 12 may have a substantially circular shape, with a diameter range of about 1 to 20 centimeters, with 5 to 20 cm spirals, and about an 0.5 to 3- centimeter deep flute ridge 34. Front frame 16 may be a semi-flexible square of about 3-30- centimeter range per side. Comers of adjacent AACs 10 may be aligned to be held together using the fastener receptor 18. The fastener receptor 18 joins adjacent coalescers loosely toallow AACs 10 to stack when the net carrying a number of AACs 10 are retrieved to the ground. A number of AACs 10 may be attached together and held by a net to form a large matrix of AACs 10 that coalesce fog and cloud micro-droplets. Such extensive arrangement produces commercial quantities of water for human, agricultural, forestation, industrial and other uses.

[0028] FIG. 3 shows an AAC 10 array 38 supported by an array support structure. In an embodiment, a net 36 serves as the array support structure. The net 36 includes net strings 40 which support an array 38 of AACs 10 to intercept aerosol carrying air. AAC 10 array 38 may intercept atmospheric gas flow when net 36 is deployed vertically and AAC 10 array 38 faces an aerosol-laden gas flow. The advantages of vertical deployment of the net 36 supporting AAC 10 array 38 facing the gas flow are to decrease lateral footprint and increase the yield of aerosol collection. Liquid water content (LWC) increases significantly from the 0.05 grams / m3for fog near the ground to more than 1.0 g / m3for low warm clouds at 50 meters and more from the ground.

[0029] FIG. 4 shows a perspective of a vertically deployed aerostat 44 supporting a fully deployed net 42 in an open atmosphere. Fully deployed net 42 supports plurality of AAC 10 arrays 38. Fully deployed net 42 is lifted by aerostat 44 and anchored to the ground 60 by main tether 46. Aerostat 44 lifts the fully deployed net 42 carrying AAC 10 array 38. Suspension rigid support 48 holds net 42 open. Aerostat 44 along with net 42 and AAC array 38 may be retrieved by winch 54 and marooned to ground 60 if no fog and cloud are present to intercept. Upper stabilizing cable yoke 50 and lower stabilizing cable 52 maintain net 42 facing the wind when deployed. Net 42, carrying AAC 10 array 38 is anchored to ground 60 by fixed tether 56 and anchor point 58. Water falling from liquid drains 22 may be collected in collection pond 58 on the ground 60. The size and orientation of collection pond 58 is determined after field piloting in the site where the system will be installed.

[0030] The fully deployed net 42 carries a number of AAC 10 arrays 38. In an embodiment, fully deployed net 42 may have a surface area of 4000 square meters and carry 400,000 of 10 cm square AACs 10. The AAC 10 arrays 38 are not shown on the net 42 because of their small scale. Each AAC 10 collection surface area is about 0.06 square meters, for the above example.

[0031] The surface area of A AC 10 includes the internal surface that contacts the passing gas and aerosol passing inside it. The total internal surface area of all AAC 10 array 38 that are supported by fully deployed net 42 may be about 25,000 square meters. At a wind speed of 3 meters per second, a liquid water content of 1 gram / m3, fifty foggy and cloudy days of the year’, a collection efficiency of 50%, and water yield efficiency of 90%, the total amount of water collected by AAC 10 arrays 38 supported by net 42 may be about 150,000 cubic meters per year. One major element to consider is the payload balance under prevailing weather conditions when the system is deployed. In the above example, the aerostat 44 is a helium filled balloon of 8-meter diameter. Such an aerostat could be supplied and safely deployed and retrieved from the company Acroballoon.com. The Acroballoon company has a good record of deploying such balloons safely to heights of 350 ft and more the past 20 years. The pay load is about 4000 kilograms. A single AAC 10 may weigh about 8 grams or less. Fully deployed net 42, tether and all other air-borne components are included. The total weight of the airborne components of the system are within the aerostat payload safety limit.

[0032] In an embodiment, the previously described setup may be deployed on a much smaller scale, such as providing a house with water from fog and clouds. A smaller number of AACs 10 in a smaller net could be deployed to much higher elevations. An aerostat that reaches this elevation with a small to medium payload is that supplied by Hcllickitc.co of the UK. It reaches 7000 ft. A very thin and light tube to convey the collected water may be attached to its tether. Such arrangement could transport the collected water from the AAC 10s to a tank to supply a dwelling with its water needs.

[0033] The advantages of various embodiments may include: a) production of good quality water from a renewable source in water stressed locations with fog and low clouds, b) enable commercial production of good quality water, c) provide an economical source of good quality water instead of desalinated seawater pumped to high elevations, d) reduce energy compared to seawater desalination lifted to mountainous regions, e) minimize effluent compared to desalination plants, f) reduced footprint due to the vertical deployment of the fog and cloud water collection system, g) less intrusive as system deploys to high elevations only when it is foggy or cloudy, h) contribute to mitigation of climate change when the system utilizes renewable energy to operate at near zero carbon footprint, I)encourage rural development of agriculture, forestry, industry and other uses that require sustainable and reasonably priced source of water, j) support covid- 19 social distancing recommendations by providing water for rural development and mitigate endemic and pandemic diseases associated with human crowding, k) support industrialization by establishing water bottling plants, and 1) collect water from plumes of thermal water cooling towers.

[0034] The combined deployment of extensive surface area of AAC 10 array 38 vertically and facing rich aerosol gas flow, high LWC due to elevation, and high efficiency of aerosol extraction due to the design of AAC 10, enable commercial production of water from fog and warm clouds. The various embodiments could extend to recovery of water from cooling tower plumes, or recovery of any liquid from a gas for other applications.

[0035] An alternative device shape and deployment are shown in FIGs. 5 and 6. FIG. 5 shows an inflated pad 74 serving as the array support structure. The inflated pad 74 includes a number of AACs 62 (FIG. 6) in an inflated pad cavities 80. The inflated pad 74 with the array of AACs 62 may be deployed at high elevation for fog / cloud water collection. The aerostat 44 lifts the inflated pad 74, which is held in place by suspension support 88. Rigid frame 78 and inflated pad stabilizing cable 88 may hold the inflated pad 74 straight and facing fog / cloud flow. Water collected by AAC 62 is discharged by water collection trough 82 held in place under inflated pad 74 by trough support cable 84 and drained by main drain 86 to a ground reservoir. Using the inflated pad 74 aids deployment with increasing payload as inflated pad 74 is made from a very strong, light and airtight material such as silicone coated nylon as used in large para-sails and may be filled with helium.

[0036] FIG. 6 is partial side view of AAC 62 plugged into inflated pad cavity 80. AAC 62 may be a spiral device with a cylindrical structure to match the shape of the inflated pad cavity. The AAC may be made of light but durable rigid plastic such as PET, aluminum, or other light, rigid materials. It receives gas laden with micro-droplets of liquid, such as in cooling tower plumes, fog, and / or clouds through its front 64. The gas flow pattern is changed by the spiral vane 68, supported by column 70, to rotational flow. Rotational motion produced by vane 68 isolates micro-droplets from gas stream and propels microdroplets of liquid to an internal wall of AAC 62, which is defined by the lining of theinflated pad cavity 80. As micro-droplets of liquid coalesce on lining pad cavity 80 their size grows to where the weight of a liquid drop overcomes the surface tension holding the drop to the pad cavity wall 80, and the drop slides to the bottom of the inflated pad cavity 80 where it is discharged outwardly through drain 72. Gas exits through the back 66 of AAC 62. Discharged liquid from drain 72 is collected in trough 82 of FIG. 5 and discharged to a ground reservoir through the main drain 86.

[0037] FIG. 7 is a flowchart describing a method 700 for collecting water from an aerosol-containing atmosphere according to an embodiment. An atmospheric aerosol coalescer (AAC) array support structure including a number of, e.g., hundreds of, AACs arranged in an array may be elevated 702 with an aerostat. Water collected by the individual AACs is collected and distributed 704 to one or more main drain(s). The collected water is then directing to 706 a water collection reservoir.

[0038] In a private test performed at the University California Irvine, the performance and efficiency of an embodiment of an AAC was compared to the performance and efficiency of a typical mesh fog collector. The AAC had a spiral shape with a 10 cm front opening and weighed 8 grams. Based on similar conditions, i.e., application of a stream of fog, the AAC harvested water with a 52.2% efficiency, compared to 5% water harvesting efficiency of the mesh fog collector erected on posts 2 meters from the ground.

[0039] FIG. 8 is a side view of an AAC water collection arrangement for cooling towers according to embodiment. Cooling tower plumes, e.g., from nuclear power plant cooling towers, are smoke-looking clouds observed when hot water vapor exiting the cooling tower stack condenses to micro-droplets of liquid water in the cooler ambient air as its temperature drops to the dew point. Micro-droplets of liquid water eventually evaporate as the cloud mixes with more ambient air and temperature of the mixture rises above the dew point.

[0040] In an embodiment, an AAC water collection arrangement captures the water micro-droplets in a zone around the outlet (top) of a cooling tower stack 100 using a cylindrical plume fog collection structure 101 with a larger diameter than stack 100 before the micro-droplets evaporate. The plume fog collection structure 101 may be erected some vertical distance over the stack 100 to allow ambient air mixing and cooling to condense thewater vapor exiting stack 100 to micro-droplets of water. AACs 102 populate the cylindrical wall of plume fog collection structure 101. A top 106 of structure 101 may be scaled with insulated material to prevent heating and eventual water evaporation.

[0041] Plume fog exits through AACs 102 due to a pressure difference created by the cylindrical collection structure 101. As plume fog exits through AACs 102 its water is deposited on their internal surfaces. Micro-droplets collected on the internal walls of the AACs 102 due to centrifugal forces and their density being approximately 1000 times that of air coalesce to larger drops and after reaching a critical size dislodge from the internal surface to the bottom of the AACs 102 where a drain discharges liquid water to trough 103. Trough 103 also collects water that may drip from the internal walls of the plume fog collection structure 101.

[0042] Collector structure 101 may be supported by columns 104. Support collector structure 101 and trough 103 may be independent of the cooling tower stack for safety reasons. AACs 102 may be loosely draped by an insulating curtain attached to the edge of insulated top 106 and outer periphery of trough 103. Such an insulating curtain may protect AACs 102 from the sun to reduce evaporation of water and heating of the outer surface of plume fog collection structure 101. Water collected by trough 103 may be discharged to storage or recycled to the base of the cooling tower through a drain 105.

[0043] Fog collection structure 101 and trough 103 may be made from sheets of plastic such as polycarbonates, or metals such as galvanized steel or aluminum, or other corrosion resistant lightweight materials. Collection structure support columns 104 may be made from galvanized steel. Top 106 may be made from polyurethane coated sheets.

[0044] In an alternative embodiment of the spiral AAC shown in 9A, diverters 75 may be provided on the surface of the spiral vane 68 at intervals for further separation of liquid water. The diverters 75 may be extend between the outer edge of the spiral vane to the inner edge of the vane, which is connected to the column. In an embodiment, the diverter may be 1 cm to 2.5 cm high, 3 cm long, depending on the length of the vane, and about 2 mm thick. The top surface of the diverter may have a rectangular shape.

[0045] In an embodiment shown in FIG. 9B, at the entry surface of the coalescer 62, the spiral vane 68 may be 40-45 degrees from the inner diameter of a cavity (also referred to as the easing or envelope) in a horizontal position.

[0046] FIG. 10 shows a hook-like portion 73 provided along the outer edge of the spiral vane, i.e, contacting the pad cavity. The hook-like portion may have an angle of 35 degrees to 55 degrees from the plane of the vane, and may provide additional turbulence as fog flows through the A AC.

[0047] The material of the coalescer may be made from from a lightweight material, each with an overall weight of, e.g., about 7-10 grams. In addition, the color of the material may be selected to minimize heating from the sun, e.g., white, and / or include a UV coating to avoid degradation from heat.

[0048] In an embodiment shown in FIG. 11, the pad holes, or cavities, in the inflated pad 74 may be within about one centimeter between one and the other in the row. Since they are circular of about 7-10 cm in diameter, the second row may be offset to increase the overall number of coalescers in the pad.

[0049] The material of the pad may be made from a very strong and very light material such as a nylon polyester rip-stop material. The outer edges of the pad may be tubular on all sides, and pipes or other structural supports may be inserted to generate a frame to keep the pad straight.

[0050] The edges of the bottom tube may be fitted with T-shaped structures through which a perpendicular pipe may be inserted to support a concave curtain for collecting the water falling from the coalescers. The edges of this water collection curtain edges may be tubular and filled with gas to flatten it. The center of the water collection curtain may include an orifice to discharge the water either to a lined pond on the ground or to a conduit to carry the collected water to the reservoir on the ground.

[0051] The conduit to transport the collected water may be made of very thin but strong lightweight material. The conduit may be tubular and made of one skin or a double skin that can be inflated to increase the buoyancy of the conduit against the pull of the water flowing through it down to the ground reservoir. The conduit may be attached to the tether tominimize the wind forces on it. The conduit is flexible to be rolled when not deployed, and be made of an FDA approved material.

[0052] The aerostat 44 may be any object that can lift the weight of the total system at its full weight including water it collects and any additional rain that may fall on it. Such objects include balloons, kites, parafoils, paragliders and other non-motorized objects. The aerostat may also include a stabilizing device such as an apron at its back to prevent it from spinning.

[0053] The aerostat can be maneuvered to rise and fall and swing right and left by manipulating strings that extend to the operator on the ground for the purpose of locating target clouds.

[0054] The aerostat may be manipulated by computer programs used in autonomous parafoils that carry very large pay loads.

[0055] The aerostat carries the inflated pad in such a way that the inflated pad does not interfere with the aerodynamics of the aerostat. The inflated pad hangs semi-vertically attached to the strings of the aerostat. The tether at the back of the inflated pad helps keep the inflated pad semi-vertical against the wind in addition to the weight of the cascading water from the coalescers.

[0056] Although various construction methods and materials have been described with respect to the various components of one preferred embodiment of the invention, many other materials and construction methods would be acceptable taking into consideration functional and structural considerations.

[0057] The foregoing method descriptions and figures are provided as illustrative examples only. The order of operations in the aspects described herein may be performed in any order. Words such as “thereafter,” “then,” “next,” etc. are used to guide the reader through the description of the methods and systems described herein, and do not limit the order of the operations. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” or “the” is not to be construed as limiting the element to the singular. Also, relative terms such as “top,” “bottom,” “upper,” “lower,” “above,” “below,” and the like as used herein describe the relative positions of elements or features, and are not limitedto the orientations depicted in the drawings. Furthermore, the specific dimensions and other details set forth with regard to specific embodiments arc for illustrative purposes only and are not intended to limit the scope of the claims.

[0058] The preceding description of the disclosed aspects is provided to enable any person skilled in the art to make, implement, or use the claims. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the claims. Thus, the present disclosure is not intended to be limited to the specific embodiments described herein but is to be accorded the widest scope consistent with the claims.

Claims

CLAIMS1. An atmospheric aerosol coalescing system comprising: an atmospheric aerosol coalescer (AAC) array support structure having a front side and a rear side and including a plurality of cavities, each cavity having a length extending from the front side to the rear side to form a cylindrical tube with an inner diameter; and a plurality of AACs, each AAC including a cylindrical column having a length corresponding to the length the cavities, a spiral vane extending along the length of the column in a spiral, the spiral vane having an inner edge connected to the column, and an outer edge, the outer edge forming an outer diameter of the AAC, wherein the outer diameter corresponds to the inner diameter of the cavities, and a plurality of drains positioned at intervals along the outer edge of the spiral vane, each drain comprising an aperture through the outer edge of the spiral vane.

2. The atmospheric aerosol coalescing system of claim 1, wherein the inner diameter of each of the cavities is 1 cm to 20 cm.

3. The atmospheric aerosol coalescing system of claim 1, wherein the plurality of cavities arc arranged in an array including a plurality of rows, and wherein the cavities in one of said rows are offset from the cavities in an adjacent row.

4. The atmospheric aerosol coalescing system of claim 1, wherein the spiral vane further comprises a plurality of diverters at intervals along the length of the AAC, each diverter extending from the outer edge to the inner edge.

5. The atmospheric aerosol coalescing system of claim 5, wherein each diverter has a height of 1 cm to 2.5 cm.

6. The atmospheric aerosol coalescing system of claim 1, wherein each AAC has a white color.

7. The atmospheric aerosol coalescing system of claim 1 , wherein each AAC has a surface with an ultraviolet coating.

8. The atmospheric aerosol coalescing system of claim 1, wherein each AAC includes a hooklike portion along the outer edge of the vane.

9. The atmospheric aerosol coalescing system of claim 1, wherein the AAC array support structure comprises an inflatable structure.

10. The atmospheric aerosol coalescing system of claim 1, further comprising: a main drain configured to receive collected water from a plurality of the AAC drain spouts; an aerostat connected to the AAC array support structure, and operable to elevate theAAC array support structure; an anchor; and a tether connected between the AAC array support structure and the anchor.

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