GB2607052A - A wind driven compressed air system - Google Patents

Abstract

A wind driven compressed air system, e.g. for water harvesting, comprising a wind driven rotor 45, a transmission (fig 3 20, 21, 22) and a centrifugal compressor, driven via the transmission by the rotor. Preferably the system is configured for water harvesting such that a condenser is provided for receiving compressed air from the compressor to condense water vapour from the air into liquid water for collection and storage. The system may also comprise a vortex tube to separate compressed air into hot and cold streams. Another separator may be connected to the compressed air source and configured for carbon capture. Preferably the transmission steps up angular velocity of an internal rotor within the compressor compared to the rotor and comprises a circular track in fixed rotation with the wind driven rotor. The system may further comprise a pump for pumping water from the storage container. Preferably the rotor rotates about a vertical axis.

Description

A wind driven compressed air system The invention relates to a system or device for harvesting water from atmospheric air. The system may also be configured for separating carbon dioxide or other gases/compounds from compressed air captured from the atmosphere.

Background to the invention

The provision of drinking water is a major concern globally. There are a number of systems available to process a water supply to a quality acceptable for drinking and other purposes, such as desalination plants and various forms of purification by filtration. Each system has a cost energy and other practical considerations as to whether it is suitable for use in a particular location.

Summary of invention

The present invention seeks to provide a platform for harvesting water directly from atmospheric air, without the need for a liquid water source such as a river, effluent outlet or ocean. In a broader sense, the invention seeks to provide a means for compressing air that can be utilised in downstream processes.

In one aspect the invention is defined according to claim 1. Further features of configuration are outlined in the dependent claims.

The device, as configured for harvesting water, according to the invention is generally comprised of a rotor (to be driven by a natural energy source such as wind), a compressor (driven by the rotor) and a condenser (for receiving compressed air from the compressor and enabling water vapour in the air to be condensed into liquid water for collection and distribution). In a particular form the device includes a vortex tube for receiving at least a portion of the compressed air and separating same into hot and cold streams. When configured for other uses, such as carbon capture, an outlet from the compressor is coupled with a separator means, instead of or in addition to a condenser. The separator may have various configurations depending on the target, e.g. carbon dioxide or other gases, particulates etc. In one form the compressor is a centrifugal compressor, e.g. with an inlet tube coaxial with the rotor. A pump, optionally driven by a portion of the compressed air, may be utilised to pump water from a collection vessel (e.g. part of the condenser chamber) for onwards use. The rotor and/or compressor may be coupled to an electric generator for providing sufficient electricity to power control features.

In one form the device is exemplified by a vertical axis of rotation, i.e. where the rotor turns about a vertical axis, actuated by air movement in a generally lateral flow. The inlet to the centrifugal compressor is likewise substantially vertical, drawing air from about the device. In alternate forms the device may be configured for a horizontal axis of rotation or any angle suitable for maximizing rotor speed.

In principle, the rotor may be actuated by other naturally occurring and hence "free" energy sources, such as a flowing river.

Compressed air is, by its nature, warmer than atmospheric air. The device provides for the hot/compressed air to be cooled, which allows a large amount of water to condense. Once the water is condensed it is then separated from the air. The condensation process is typically completed via an aftercooler, or a heat exchanger that cools the hot compressed air in order to precipitate the water.

The device is self-contained and may be deployed in any environment where there is sufficient wind to drive the compressor. All environments on Earth have a relative humidity, however low, which can potentially be condensed out of the compressed air for use as a potable water source. In any event, compressed air separated into hot and cold streams can be put to various uses, including heating and/or refrigeration.

The invention is a multi-stage device according to the appended claims. In one form the wind driven rotor may be stacked with a second unit and/or is extendable in height to present greater surface area to the wind, thereby increasing torque.

A transmission assembly transmits rotational motion, in a stepped-up ratio, from the first rotor to a second rotor, e.g. a centrifugal compressor. The second rotor is coaxial with the first.

A transmission assembly can be broadly interpreted as any mechanism that transfers and/or steps up/down rotational velocity about one or more rotational axes, i.e. the initial wind powered propeller/rotor is driven by wind at a specific speed measured in revolutions per minute, while a second fan assembly/compressor downstream rotates at a higher rate.

In a form of the invention described herein, the first rotor and compressor each turn in a vertical/perpendicular axis relative to a horizontal/sideways plane associated with the flow of horizontal kinetic/air movement, Any conceivable wind powered rotor design is possible, e.g. an alternative external blade or screw design or a propeller or "aerofoil" within its normally recognised meaning. All alternatives are deemed to be within the scope of the invention. The inventive concept envisages using wind as a motivator to turn a rotor for driving a compressor fan or equivalent means to compress air, ultimately for condensing out water vapour or other uses described herein.

Brief description of the drawings

Figure 1 illustrates an external overview of a device for water harvesting according to the invention; Figure 2 illustrates a variation of the device, having a doubled height; Figure 3 illustrates an internal overview of components for the device; Figure 4 illustrates a further view of internal components where the rotor is removed; Figure 5 illustrates an internal view of components toward a base of the device, particularly showing a transmission and outlet of a centrifugal compressor; Figure 6 illustrates a closer view of the transmission; Figure 7 illustrates a closer view of the transmission and compressor fan; Figure 8 illustrates a view of the base, including a condenser tank; Figure 9 illustrates a schematic view of a vortex tube; Figure 10 graphically illustrates how water content increases with increasing water temperature; Figure 11 illustrates an overview of first alternative device; Figures 12, 13 and 14 illustrate various views of the transmission for the first alternative; Figure 15 illustrates an overview of a second alternative device; Figure 16 illustrates an internal view of transmission and compressor for the second device; and Figure 17 illustrates a view of carbon capture end use for the system.

Detailed description of an embodiment of the invention Advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings that illustrate various aspects of a main embodiment of the invention. However, the scope of the invention is not intended to be limited to the precise details of the main embodiment, with variations apparent to a skilled person deemed also to be covered by the description of this invention.

Terms for components and materials used herein are to be given a broad interpretation that also encompasses equivalent functions and features. Descriptive terms should be given the broadest possible interpretation; e.g. the term "comprising" as used in this specification means "consisting at least in part of". Additionally, the present description refers to embodiments with particular combinations of features, however, it is envisaged that additional combinations and cross-combinations of compatible features between embodiments will be possible. Indeed, isolated features may function independently from other features and not necessarily be implemented as a complete combination.

Figure 1 shows a tower 10 comprised of a rotating cylinder 11, mounted from a rotationally fixed base 12, associated with a ground surface G. The base may have an access hatch 13 for maintenance by a workman at the ground level.

Figure 2 shows an overhead view where the height of cylinder 11 has been doubled, denoted 11a, e.g. by telescopic extension or as a stacked unit. From the perspective shown, cut-outs 14 in the cylinder 11 are visible which facilitate aerodynamic rotation of the cylinder in a vertical configuration defined by axle 15. Air movement generally occurs laterally to the cylinder, e.g. wind blowing in a direction as denoted by arrow A. The rotor structure 16 may take various forms of known vertical axis wind turbine design.

Internal components of the tower are shown by Figure 3, e.g. a rotor 16 that provides a mounting frame for cylinder 11. Rotor 16 is supported by a bearing 17 to enable free rotation about a vertically oriented hollow shaft 18 that serves as a longitudinal axis (V) and an inlet for a centrifugal compressor 19 at a base of the rotor structure.

A circular track 20, having a diameter corresponding to rotor 16 (although it may be greater or lesser in diameter), defines part of a transmission mechanism for driving the centrifugal compressor 19, shown in more detail by Figure 6. Specifically, a toothed cog 21 mounted on a laterally extending bracket engages with an internal toothed surface of track 20 which, as the track rotates about a central axis, causes a significant step-up in revolutions per minute. Cog 21 may transfer rotational movement 1:1 or via another step change by a belt 22 to a drive shaft 23 of the centrifugal compressor 19, thereby spinning its fan 24, as shown by Figure 7. Cog 21 may be engaged permanently or via a clutch and/or gear arrangement or the like to ensure there is sufficient power in the rotor assembly to overcome the torque required to initiate rotation of compressor fan 24.

It will be apparent, by way of the configuration explained above, that as the wind blows in direction A cylinder 11 begins to rotate along with ring 20 and, following engagement with a step up transmission, the centrifugal compressor is activated to draw in atmospheric air through inlet 18 and eject compressed air via an outlet 25, in communication with a condenser chamber 26. The centrifugal compressor operates at significantly greater rpm than the external rotor.

At the outlet 25 or downstream thereof, a vortex tube 27 provides for splitting at least a portion of the compressed air stream into hot and cold streams in accordance with the properties discovered by Ranque and Hilsch in the early twentieth century. A representation of a vortex tube is shown by Figure 9 where compressed air X separates into a hot stream H, outlet proximate to a conical nozzle end of the tube, and a cold stream C. The hot and cold streams may be utilised to improve operation of the condenser chamber 26 that is otherwise arranged according to known principles, e.g. where the cold stream refrigerates a plate in the condenser and moisture precipitates out of the hot compressed air. The hot stream may join back to the main compressed air.

Compressed air, which by its nature has an elevated temperature, contains water content that condenses/precipitates when in contact with a colder surface (e.g. in part refrigerated by cold stream C). Figure 10 shows a water content curve (to temperature) for air having 40% relative humidity.

Figure 8 illustrates a view of the base 12 which serves as a cover for an underground collection vessel 29 for water obtained in condenser 26 that is in communication therewith. Base 12 features a central column 28, upon which the centrifugal compressor is mounted, an access hatch 30 and an outlet pipe 31. A siphon (not visible) may extend toward an internal base of the vessel 29 in order to pump out collected water; e.g. by an internal pump (not visible), such as an impeller pump powered by compressed air from a lateral airline 32 seen in Figure 5. Water can be piped for delivery into a building, stored or transported as needed.

Figure 11 illustrates an alternative form of wind driven tower for harvesting water. In this embodiment a support column 33 provides the necessary height to mount a rotor 34 from which radiate a plurality of blades 35. The general configuration is still "vertical" as in Figures 1 to 10, where the scooped blades 35 capture energy from wind flowing transversely to column 33. Rotational energy is transmitted via a main drive shaft 36 that extends from the hub of a fan 37 at the opening to a compressor housing 38.

Referring to Figures 12 to 14, an edge/rim of fan 37 (driven by rotor 34) includes an annular toothed surface 39 engaged with a small cog 40, serving as a step-up gear via transmission shaft 41 to a belt drive 42. Belt drive 42 ultimately causes rotation of a drive shaft 43 of a centrifugal compressor (not shown). An outlet pipe 44 delivers fluid for onwards use/processing. A condenser may be built into the compressor housing 38 (in which case pipe 44 carries water to a storage vessel) or pipe 44 may carry compressed air for subsequent condensing and/or carbon capture etc. Figures 15 to 17 illustrate a further alternative embodiment, namely where a roof mounted system is provided. A wind capture (mini) tower 45 is located on a tiled roof surface or any other suitable elevated position. Tower 45 may be disguised behind a gauze material, e.g. to appear like a chimney or other common structure. When the wind blows the rotor column 45 (comprised of multiple vertical fins) is caused to move and, via a transmission 46/47, drives a compressor (e.g. centrifugal compressor) to create a vacuum for drawing air into the device, compressing it for onwards use. As in the embodiment of Figures 11 to 14, a base of the rotor 45 includes a fan 48 for assisting/directing air into the centrifugal compressor.

An outlet pipe 49 carries compressed air from the compressor, as powered by the wind, for onwards processing; e.g. the pipe 49 is connected to a junction box 50 housing a CO2 filter/separator 51 and a gas storage bottle 52. The separator 51 may be of a hollow fiber carbon membrane type, where millions of hollow fibers are combined to form a module within a separator housing having an inlet for compressed gas (49), a first outlet for a CO2 rich stream 53 and a second outlet 54 of cleaned air.

The carbon cleaned air 54 is very hot and may be directed into a heat exchanger in contact with water to provide hot water for domestic use.

In summary, the invention involves provision of a water harvesting and/or carbon capture system, comprising a wind driven rotor, a transmission and a centrifugal compressor (19) driven via the transmission by the rotor. An outlet of the centrifugal compressor may be directed to a condenser and/or a carbon capture means such as a CO2separator.

The system is thereby configured for condensing water vapour in the air into liquid water for collection and storage. A vortex tube, separating compressed air into hot and cold streams, improves efficiency of the condenser by refrigerating a surface in contact with the hot compressed air. Alternatively, or in addition, the system may be configured for capturing CO2 from compressed air.

Claims (13)

1. Claims 1. A wind driven compressed air system, comprising: a wind driven rotor; a transmission; a centrifugal compressor, driven via the transmission by the rotor, having an inlet for drawing in atmospheric air and an outlet for supplying compressed air.
2. 2. The system of claim 1, further comprising a condenser for receiving compressed air from the outlet, configured for condensing water vapour in the air into liquid water for collection.
3. 3. The system of claim 2, further comprising a vortex tube for receiving at least a portion of compressed air from the compressor, configured for separating said compressed air into hot and cold streams.
4. 4. The system of claim 3, wherein hot and/or cold streams of the vortex tube are utilised for enhancing operation of the condenser.
5. 5. The system of any preceding claim, further comprising a separator.
6. 6. The system of any preceding claim, wherein the inlet is coaxial with an axis of rotation of the rotor.
7. 7. The system of any preceding claim, wherein the transmission steps up angular velocity of an internal rotor within the compressor, compared to the rotor.
8. 8. The system of any preceding claim, wherein the transmission comprises a circular track in fixed rotation with the wind driven rotor driving a drive shaft 10 of the compressor.
9. 9. The system of any preceding claim2 to 4, further comprising a pump, optionally driven by a portion of the compressed air, for pumping water from a storage container in communication with the condenser
10. 10. The system of any preceding claim, wherein the rotor and/or compressor are coupled to an electric generator for providing sufficient electricity to power a controller.
11. 11. The system of any preceding claim, wherein the rotor is configured for rotation about a vertical axis.
12. 12. The system of claim 5, wherein the separator comprises hollow fiber tubes for separation of carbon dioxide.
13. 13. The system of claim 5 or 12, wherein the separator comprises a first outlet coupled to a gas storage container and a second outlet for hot gas.