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Louis MICHAUD
Atmospheric Vortex Engine
ATMOSPHERIC VORTEX ENGINE DESCRIPTION
Louis Michaud, P. Eng. - April 2021
[ PDF ]
https://www.worldgreenbridge.org/page105.html
AVETEC ENERGY CORPORATION CANADA
LOUIS MICHAUD // CAMARON BECCARIO
Louis Michaud is the President of of AVEtec Energy Corporation residing in Ontario Canada.
INVENTION OF THE AVE
Based on the huge amount of mechanical and thermal energies of cyclones, Louis Michaud proposed the atmospheric vortex engine (AVE). A very original and unusual device for capturing mechanical energy during upward heat-convection in the atmosphere.
BREAKOUT LABS
His version of atmospheric vortex engine (AVE) was back in 2012 granted by Peter Thiel's Breakout Labs. Breakout Labs is an initiative of Peter Thiel and Elon Musk that awards revolutionary technical proposals.
ESTIMATED ATMOSPHERIC EXERGY BUDGET
The AVE will capture the energy that is produced when heat is carried upward by convection in the atmosphere. (Just like in hurricanes, tornadoes or dust devils.) Such a man-made vortices will reach high into the sky and act like a very tall chimney.
ALTERNATIVE ENERGY SOURCES
The heat source can be solar energy, warm sea water, warm humid air, or even waste heat rejected in a cooling tower.
AVE
The developed atmospheric vortex engine (AVE)consists of a cylindrical wall, open at the top and with tangential air entries around the base. Heating the air within the wall using a temporary heat source such as steam starts the vortex. Once the vortex is established, it could be maintained by the natural heat content of warm humid air or by the heat provided by cooling towers.
Cooling towers are commonly used to transfer waste heat to the lower atmosphere. Louis Michaud’s AVE is supposed to increase the effciency of a thermal power plant by reducing the temperature of the heat sink from plus 30 degrees Celsius at the bottom of the atmosphere to — 70 degrees Celsius at the bottom of the stratosphere.
The AVE process can provide large quantities of renewable energy, alleviate global warming, providing precipitation.
RELUCTANCE
Of course, there is reluctance to attempt to reproduce such destructive phenomenon as a tornado. But AVE created tornadoes are very controllable by means of the tangential air entries. A small vortex firmly anchored over a strongly built station would not be a hazard.
https://inhabitat.com/atmospheric-vortex-engine-harnesses-the-power-of-tornadoes-to-create-clean-energy/
Atmospheric Vortex Engine Harnesses the Power of Tornadoes to Create Clean Energy
https://macleans.ca/education/a-man-made-vortex-is-creating-carbon-free-energy-from-waste-heat/
A man-made vortex is creating carbon-free energy from waste heat
Louis Michaud is collaborating with Lambton College to create vast quantities of low-cost carbon-free electricity from waste heat
Lambton had been working with local energy innovators since 2009, so in 2013, after patenting the AVE (for atmospheric vortex engine), Michaud approached the college for help building a prototype and attracting capital to commercialize his discovery (one early backer, PayPal founder Peter Thiel, contributed $350,000). The college’s testing process involved Lambton faculty and students studying instrumentation and control systems, as well as data gathering and processing...
https://en.wikipedia.org/wiki/Vortex_engine
Vortex engine
The concept of a vortex engine or atmospheric vortex engine (AVE), independently proposed by Norman Louat [1] and Louis M. Michaud,[2] aims to replace large physical chimneys with a vortex of air created by a shorter, less-expensive structure. The AVE induces ground-level vorticity, resulting in a vortex similar to a naturally occurring landspout or waterspout.
An Australian experimental atmospheric vortex using smoke as the tracer. Geoffrey Wickham.
Michaud's patent claims that the main application is that the air flow through the louvers at the base will drive low-speed air turbines, generating twenty percent additional electric power from the heat normally wasted by conventional power plants. That is, the vortex engine's proposed main application is as a "bottoming cycle" for large power plants that need cooling towers.
The application proposed by Louat in his patent claims is to provide a less-expensive alternative to a physical solar updraft tower. In this application, the heat is provided by a large area of ground heated by the sun and covered by a transparent surface that traps hot air, in the manner of a greenhouse. A vortex is created by deflecting vanes set at an angle relative to the tangent of the outer radius of the solar collector. Louat estimated that the minimum diameter of the solar collector would need to be 44+ metres in order to collect "useful energy". A similar proposal is to eliminate the transparent cover.[3] This scheme would drive the chimney-vortex with warm seawater or warm air from the ambient surface layer of the earth. In this application, the application strongly resembles a dust devil with an air-turbine in the center.
Since 2000, Croatian researchers Ninic and Nizetic (from the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture University of Split) have also developed this technology[4] and patents.[5][6]
The solar research team at Universiti Teknologi PETRONAS (UTP), Malaysia, headed by Prof. Hussain H. Al-Kayiem, developed the first experimental prototype of a solar vortex power generation (SVPG) technology that uses solar energy as a heat source.[7] The basic prototype was then subjected to a series of developments and performance enhancements by integration with sensible thermal energy storage (TES) and modification in the design of the vortex generator. The team carried out and published an experimental evaluation, theoretical analysis, and computational simulations of the SVPG and compiled the findings in a book which summarizes the fundamentals of this technology.[8]
Theory of operation
In operation, the vortex centripetally expels heavier, colder external air (37), and therefore forms a large, low-pressure chimney of hot air (35). It uses about twenty percent of a power-plant's waste heat to drive its air motion. Depending on weather, a large station may create a virtual chimney from 200 m to 15 km high, efficiently venting waste power plant heat into colder upper atmosphere with minimal structure.
The vortex is begun by briefly turning on a diffuse heater (83) and electrically driving the turbines (21) as fans. This moves mildly heated air into the vortex arena (2). The air must have only a mild temperature difference because large temperature differences increase mixing with cold ambient air and reduce efficiency. The heat might be from flue gases, turbine exhaust or small natural gas heaters.
The air in the arena rises (35). This draws more air (33, 34) through directing louvers (3, 5), which cause a vortex to form (35). In the early stages, external airflow (31) is restricted as little as possible by opening external louvers (25). Most of the heat energy is at first used to start the vortex.
In the next stage of start-up, the heater (83) may be turned off and the turbines (21) by-passed by louvers (25). At this time, low-temperature heat from an external powerplant drives the updraft and vortex via a conventional crossway cooling tower (61).
As the air leaves the louvers (3, 5) more rapidly, the vortex increases in speed. The air's momentum causes centrifugal forces on the air in the vortex, which reduce pressure in the vortex, narrowing it further. Narrowing further increases the vortex speed as conservation of momentum causes it to spin faster. The speed of spin is set by the speed of the air leaving louvers (33, 34) and the width of the arena (2). A wider arena and faster louver speed cause a faster, tighter vortex.
Heated air (33, 34) from the crossway cooling tower (61) enters the concrete vortex arena (2) via two rings of directing louvers (3, 5, height exaggerated for clarity) and rises (35). The upper ring of louvers (5) seals the low-pressure end of the vortex with a thick, relatively high-speed air-curtain (34). This substantially increases the pressure difference between the base of the vortex (33) and the outside air (31). In turn, this increases the efficiency of the power turbines (21).
The lower ring of louvers (3) convey large masses of air (33) almost directly into the low-pressure end of the vortex. The lower ring of louvers (3) are crucial to get high mass flows, because air from them (33) spins more slowly, and thus has lower centripetal forces and a higher pressure at the vortex.
Air-driven turbines (21) in constrictions at the inlet of the cooling tower (61) drive electric motor-generators. The generators begin to function only in the last stages of start-up, as a strong pressure differential forms between the base of the vortex arena (33) and the outside air (31) At this time, the bypass louvers (25) are closed.
The wall (1) and bump (85) retain the base of the vortex (35) in ambient winds by shielding the low-velocity air-motion (33) in the base of the arena, and smoothing turbulent airflow. The height of the wall (1) must be five to thirty times the height of the louvers (3, 5) to retain the vortex in normal wind conditions.
To manage safety and wear of the arena (2), the planned maximum speed of the vortex base (33) is near 3 m/s (10 ft/s). The resulting vortex should resemble a large, slow dust-devil of water-mist more than a violent tornado. In uninhabited areas, faster speeds might be permitted so the vortex can survive in faster ambient winds.
Most of the unnamed numbered items are a system of internal louvers and water pumps to manage air velocities and heating as the engine starts.
Criticism and history
In early studies it was not absolutely clear that this could be made workable due to cross-wind disruption of the vortex.[9][10] This motivated later studies with wind tunnel empirical validation of the CFD model, which conclude, "The full scale simulations subjected to cross wind show that the power generation capacity is not affected by the cross winds."[11]
Michaud has built a prototype in Utah with colleague Tom Fletcher.[12]
Also, according to Michaud's patent application, the design was initially prototyped with a gasoline-powered 50 cm "fire-swirl".
The University of Western Ontario's wind-tunnel laboratory, through a seed investment from OCE's Centre for Energy, is studying the dynamics of a one-metre version of Michaud's vortex engine.[13]
PayPal founder Peter Thiel's Breakout Labs sponsored an AVE test with a (2012) $300,000 grant.[14] The preliminary results (2015) for which were reported in The Atlantic.[15]
Disambiguation
The term « Vortex Engine » also refers to a new kind of internal combustion engine.[16]
References
Louat's International Patent Application is PCT/AU99/00037. International publication number WO0042320 [1]
Michaud's U.S. Patent is US 2004/0112055 A1, "Atmospheric Vortex Engine"
Atmospheric Vortex Engine
Sandro Nizetic (2011). "Technical utilisation of convective vortices for carbon-free electricity production: A review". Energy. 36 (2): 1236–1242. doi:10.1016/j.energy.2010.11.021.
Ninic Patent is HRP20000385 (A2), published in 2002, title: "SOLAR POWER PLANT INCLUDING A GRAVITATIONAL AIR VORTEX" [2]
Nizetic Patent is WO2009060245, published in 2009, title: "SOLAR POWER PLANT WITH SHORT DIFFUSER" [3]
Al-Kayiem, Hussain H.; Mustafa, Ayad T.; Gilani, Syed I. U. (2018-06-01). "Solar vortex engine: Experimental modelling and evaluation". Renewable Energy. 121: 389–399. doi:10.1016/j.renene.2018.01.051. ISSN 0960-1481. S2CID 115355306.
"Solar Vortex Engine / 978-3-330-06672-4 / 9783330066724 / 3330066725". www.lap-publishing.com. Retrieved 2020-06-29.
Michaud LM (1999). "Vortex process for capturing mechanical energy during upward heat-convection in the atmosphere" (PDF). Applied Energy. 62 (4): 241–251. doi:10.1016/S0306-2619(99)00013-6. Archived from the original (PDF) on 2006-09-28. Retrieved 2006-07-10.
Michaud LM (2005) "Atmospheric Vortex Engine" (PDF). (198 KiB)
Diwakar Natarajan PhD Thesis
Staedter, Tracy (9 November 2005). "Fake tornado gives energy new twist". ABC Science. Retrieved 18 September 2015.
Christensen, Bill (24 July 2007). "Vortex Engine - Tame Tornadoes May Generate Power". Technovelgy LLC. Retrieved 18 September 2015.
Boyle, Rebecca (18 December 2012). "Peter Thiel's Latest Pet Project: Tornado-Powered Energy". Popular Science. Retrieved 18 September 2015.
"How To Build a Tornado".
"Un Moteur Rotatif à Vortex Torique".
https://www.theatlantic.com/video/index/384905/how-to-build-a-tornado/
How to Build a Tornado // Video by The Atlantic
https://aeon.co/videos/meet-the-man-bent-on-powering-the-world-with-vortexes
Tornado Man
https://www.youtube.com/watch?v=9ybGcgqQzCM
The Man who Wants to Power the World with Tornadoes // The Adaptors
https://www.youtube.com/watch?v=IJB33rh2EhQ
The Solar Vortex Engine
R. Murry-Smith
https://1lib.sk/book/17892420/7ddf06/freestanding-chimneys-brick-liners-design-and-execution.html
Free-Standing Chimneys. Brick Liners. Design and Execution
British Standards Institute Staff
[ PDF ]
MICHAUD LOUIS:
ENHANCED VORTEX ENGINE
US7938615
[ PDF ]
The invention covers improvements to the Atmospheric Vortex Engine. A tornado-like convective vortex is produced by admitting air at the base of a cylindrical wall via tangential entry ducts. The heat required to sustain the vortex is provided in peripheral heat exchange means located outside the cylindrical wall. The heat source for the peripheral exchange means can be waste industrial heat or warm sea water. The preferred heat exchange means is a cross-flow wet cooling tower. The mechanical energy is produced in a plurality of turbines. The air can enter an arena via tangential entries or via an opening at the center of the arena floor. The invention can be used to produce mechanical energy, to reduce the temperature of cooled water or to produce precipitation. The invention includes a circular forced draft cooling tower that can operate in non-vortex mode or in vortex mode.
CROSS REFERENCE TO RELATED APPLICATION
[0001] This specification is a Continuation-in-Part of issued U.S. Pat. No. 7,086,823.
FIELD OF INVENTION
[0002] The invention relates to the electrical energy industry and captures energy produced when heat is carried upward by convection in the atmosphere. The invention relates to renewable energy specifically to the solar chimney. The invention relates to the waste heat disposal industry specifically to the cooling tower and the fin-fan cooler industry. The invention relates to the field of meteorology and involves the production of a vortex similar to a natural tornado. The invention can produce precipitation and alleviate global warming.
BACKGROUND OF THE INVENTION
Review of Prior Art
[0003] Over half of the thermal energy input to a power plant is rejected as low temperature waste heat. Waste heat disposal is a costly part of the power production. Cooling options include once-through heat rejection to water body, and recirculating heat rejection to the atmosphere. Once-through cooling is only practical where a large water body is available and when returning warm water is not environmentally objectionable. Cooling towers and fin-fan coolers are commonly used to dispose of waste heat in the atmosphere. The most common device for transferring waste heat to the atmosphere is the wet cooling tower. There are two main types of wet cooling towers: natural draft cooling towers and mechanical draft cooling towers. Natural draft cooling towers are among the largest structures built and have a very high capital cost. Natural draft cooling towers can be 200 m high. Mechanical draft cooling towers are less expensive than natural draft cooling towers but require fans to circulate the air through falling water and electrical power to drive fans. Up to 1% of the electrical power produced in the power plant can be consumed in driving the cooling tower fans. The invention replaces the physical stack of the natural draft cooling tower with a vortex eliminating both the hyperbolic stack and the need for fan power.
[0004] A solar chimney is a solar engine that captures the energy produced during upward heat convection. A solar chimney requires a very high physical chimney surrounded by a very large area of solar collector. The present invention replaces the physical chimney with a vortex and eliminates the need for the solar collector by using waste industrial heat, warm humid air or warm sea water as its heat source.
BACKGROUND OF THE INVENTION
Objects and Advantages
[0005] The vortex engine is a major improvement on conventional waste heat disposal systems. The invention could be used to replace conventional cooling towers with superior devices. The invention increases the output of thermal power plants by capturing the mechanical energy produced when waste heat is carried upward in the atmosphere. In addition, the invention increases the output of thermal power plants by reducing cooled water temperature. The invention could be used to produce precipitation, to reduce surface temperature, to reduce instability and severity of storm, to reduce pollution by washing or lifting surface air, or to alleviate global warming by expediting upward heat transport and by reducing fossil fuel consumption.
[0006] The invention produces its maximum power during periods of high insulation and low wind. Its peak power production period corresponds to periods of high electrical load and to periods of low wind when conventional wind power is unavailable. Wet cooling towers are large water consumers because the cooling results from evaporating a small fraction of the water circulating in the cooling tower. Lack of water is forcing some thermal power plants to use less efficient and more costly dry cooling tower. With conventional wet cooling towers, the upward heat convection and associated precipitation occurs well away from the cooling tower and does not contribute to the local rainfall. A vortex cooling tower could produce precipitation in the local watershed thereby making up for the water evaporated in the cooling tower.
SUMMARY
[0007] An Atmospheric Vortex Engine uses a tornado-like vortex to capture the mechanical energy produced when heat is carried upward by convection in the atmosphere. The vortex is produced by admitting air tangentially in the base of a vertical axis cylindrical wall. The volume within the cylindrical wall wherein the vortex forms is called the “arena”. The air entering the arena can have natural heat content, can be heated in a peripheral heat exchanger located upstream of the tangential entries and outside the cylindrical wall, or can be heated by solar radiation in a solar collector surrounding the cylindrical wall. The heat source for the peripheral heat exchanger can be waste industrial heat or warm sea water. The vortex can be started using a variety of devices including: heating the air in the arena with fuel or steam, using steam jets to entrain air in the tangential entries while at the same time increasing the temperature and vapor content of the air, or by pushing air in the arena via the tangential entries with forced draft fans. Once the vortex has been established, the starting device can be turned off. The mechanical energy is captured with turbo-generators located upstream of the tangential entries. The invention turns costly to dispose of waste heat into an energy producing asset.
a) Cooling Towers
[0008] The heat exchanger can be any of the many heat exchanger types used in industry. The preferred heat exchange means is a cross-flow wet cooling tower. Alternate types of heat exchangers could include: other types of wet cooling towers, dry cooling towers, finned tubes process coolers and direct steam condensers. The invention can incorporate any of the prior cooling tower industry inventions. Known features of cooling towers are therefore not detailed in this specification. Given the heat duty the cooling industry is able to design an appropriate cooling tower.
[0009] The normal purpose of cooling towers is to reduce the temperature of water or other fluids. The process fluid, usually water, is cooled by transferring heat from the process fluid to the atmosphere. Cooling towers are heat exchangers which simultaneously reduce the heat content of the fluid to be cooled and increase the heat content of air. The heat exchanger transfers enthalpy from water to air; the enthalpy decrease of the water is equal to the enthalpy increase of the air. A cooling tower is both a water cooler and an air heater-humidifier. In the cooling tower industry, the primary purpose of a cooling tower is to cool the process fluid. In the atmospheric vortex engine, the primary purpose of the cooling tower is to heat the air. The term “cooling tower” is retained because it is widely used in industry. This specification uses standard cooling tower terminology where applicable. A “cooling cell” is the smallest subdivision of a cooling tower which can function as an independent unit with regard to air and water flow. A “cooling cell” includes: cell fill, drift eliminators, louvers, warm and cold water basins, and associated fan. A “vortex engine sector” is a cooling cell and associated equipment not located within the cooling cell such as: turbo-generator, tangential entry duct, and associated flow restrictors.
[0010] Alternately the device for heating the air can be a solar heat collector covered with a transparent roof similar to the solar collector of solar chimney. The solar heat collector would surround the cylindrical wall. Ambient air would enter the open outer rim of the solar collector. Heated air would leave the inner rim of the solar collector and enter the cylindrical wall via tangential entries. The cylindrical wall of the vortex engine would protect the solar collector from damage by the vortex. Alternatively the solar collector could be solar ponds from which solar heated water would be pumped to cooling cells to transfer heat form water to air.
b) Expanders
[0011] Devices within which a gas is expanded to produce work are generically known as expanders. Expander types include: turbines, and positive displacement pistons. Turbines can have axial or radial flow. Axial flow turbines are the more common type. Given air flow and differential pressure the expander industry is able to design an appropriate expander. The turbo-generators can incorporate any prior turbo-generator industry inventions. The terms expander, turbo-expander, expansion turbine and turbine will be used interchangeably. A turbo-generator is a turbine with an attached generator. An ideal expander has an efficiency of 100% and its outlet entropy equals its inlet entropy. Real expanders have efficiency of 80% to 90% and outlet entropy slightly higher than inlet entropy. Efficiency reduction is associated with entropy increase.
[0012] The preferred expander is an axial turbine. There are two types of axial turbines:
Turbines with inlet nozzles and with fixed pitch rotating blades similar to the last few stages of the expander part of a gas-turbine. In a vortex engine, the compressor part of the gas-turbine is not required. The air flow is controlled by covering and uncovering fixed inlet nozzles. The expander does not have to withstand the high temperatures encountered in gas-turbines. Turbines with inlet nozzles could be the preferred expander at turbine differential pressure above approximately 1 kPa. More than one stage may be appropriate at turbine differential pressure over 5 kPa.
Turbines without inlet nozzles and with variable pitch blades similar to helicopter rotors. There are no inlet nozzles and the air flow is controlled by varying blade pitch and electrical load. Turbines without inlet nozzles could be the preferred at differential pressure under approximately 1 kPa.
[0015] Both turbines with and without inlet nozzles have significantly higher differential than conventional wind turbines. The mechanical energy produced per unit area of rotor blade increases with differential pressure. The diameter of a vortex engine turbine with a given mechanical energy rating is much smaller than the diameter of conventional wind turbine of the same rating. Turbines without inlet nozzles can be made to act as fans by using the generator as a motor. Turbines with inlet nozzles cannot be used as fans. The forced draft fan used to start the vortex could become a turbine once the vortex is established.
[0016] Enhancements covered by this continuation specification are described in a new elements section following the presentation and description of the new drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Parent Specification U.S. Pat. No. 7,086,823 uses figure numbers 1 to 6. This Continuation-in-Part Specification uses figure numbers starting at 7. A better understanding of the present invention can be obtained when the following detailed description of the preferred embodiment is considered in conjunction with the following drawings, in which:
[0018] FIG. 7 is a plan view of atmospheric vortex engine with tangential entry ducts.
[0019] FIG. 8 is an elevation view of atmospheric vortex engine with tangential entry ducts.
[0020] FIG. 9 is a plan view of circular cooling tower with forced draft fans in the tower inlet.
[0021] FIG. 10 is an elevation view of circular cooling tower with forced draft fans in the tower inlet.
[0022] FIG. 11 is a plan view of circular cooling tower capable of operating in vortex or non-vortex mode.
[0023] FIG. 12 is an elevation view of circular cooling tower capable of operating in vortex or non-vortex mode.
[0024] FIG. 13 is a plan view of vortex engine with an uninterrupted front face and a circular cooled water channel.
[0025] FIG. 14 is a cross-section through a cooling cell/heat exchanger.
[0026] FIG. 15 is a plan view of vortex engine with elevated floor.
[0027] FIG. 16 is a cross-sectional view of a vortex engine with elevated floor.
DRAWING REFERENCE NUMERAL
FIGS. 7 and 8
[0028]
401 Heat exchanger
403 Arena floor
404 Arena
405 Cylindrical wall
406 Inter annular ring air entry
407 Warm water inlet
408 Cooled water outlet
411 Turbo-generator (outlet to cooling cell)
412 Forced draft fan (optional)
415 Turbo-generator (optional) (outlet to tangential entry duct)
421 Linear tangential entry duct
422 Tangential entry duct restrictor
423 Reverse circulation air entry
425 Tangential entry duct straightening vanes
426 Steam jet
431 Underground airways for intermediate radius floor tangential air entry (with steam injector)
432 Airway curved exit
433 Airway steam injector
434 Underground airways for
435 Underground air tunnel
441 Circular underground room
442 Circular room roof
445 Circular room roof opening
451 Convergence roof
452 Annular ring
455 Convergence roof circular opening
461 Cylindrical wall lower end
462 Cylindrical wall upper end
463 Cylindrical wall upper end opening
467 Turbine
468 Generator
481 Cylindrical wall lower end air opening
482 Tangential entry duct air inlet
483 Tangential entry duct air outlet
487 Tangential entry duct inner wall
488 Tangential entry duct outer wall
491 Heat exchanger air inlet
492 Heat exchanger air outlet
DRAWING REFERENCE NUMERAL
FIGS. 9 and 10
301 Heat exchanger
304 Arena
305 Cylindrical wall
325 Radial air entry
326 Forced draft fan
340 Convergence roof
342 Convergence roof opening
346 Stack
350 Cooled water basin
351 Pump sump
352 Cooled water equalizing pipes
DRAWING REFERENCE NUMERAL
FIGS. 11 and 12
501 Heat exchanger
505 Cylindrical wall
521 Linear tangential entry air duct
525 Radial or reversed rotation air-entry
526 Forced draft fan or Turbo-generator
540 Convergence roof
541 Convergence roof opening
550 Cooled water basin
551 Pump sump
552 Water equalizing line
DRAWING REFERENCE NUMERAL
FIG. 13
702 Cylindrical wall
704 Cooling tower uninterrupted front
706 Heat exchanger
712 Turbo-generator
714 Linear tangential entry duct
716 Convergence roof
718 Convergence roof opening
732 Warm water Inlet pipe
734 Underground cooled water pipe
736 Circular cooled water channel
738 Cooled water pump sump
781 Cylindrical wall lower end opening
782 Tangential entry duct air inlet
783 Tangential entry duct air outlet
DRAWING REFERENCE NUMERAL
FIG. 14
802 Cylindrical wall
804 Heat exchanger
805 Cooling cell air inlet wall
806 Cooling air outlet wall
807 Cooling cell sub-atmospheric enclosure
810 Warm water inlet pipe
812 Warm water distributor tray
813 Cross-flow nozzles
814 Cooling tower fill
816 Louvers
818 Drift eliminators
820 Cooled water drain pipe
822 Cooled water seal
824 Circular cooled water channel
826 Cooled water pump
828 Pump motor
830 Cooled water pipe
840 Outside grade
842 Arena floor
850 Turbine
852 Generator
854 Baffle
856 Linear tangential entry duct
858 Convergence room
865 Turbine air inlet
866 Turbine air outlet
891 Heat exchanger air inlet
892 Heat exchanger air outlet
DRAWING REFERENCE NUMERAL
FIGS. 15 and 16
[0033][0000]
901 Heat exchanger
902 Grade level base
903 Elevated floor
904 Arena
905 Cylindrical wall
906 Under floor plenum
907 Warm water inlet
908 Cooled water outlet
911 Turbo-generator
916 Under floor air entry restrictor
917 Circular room entry peripheral wall or deflector ring
921 Linear tangential entry duct
925 Steam jet
932 Intermediate radius floor tangential air entry
941 Circular central room
942 Circular room roof
945 Circular room roof opening
951 Convergence roof
952 Annular ring
953 Inter ring air entry
955 Convergence roof opening
961 Cylindrical wall lower end
962 Cylindrical wall upper end
963 Cylindrical wall upper end opening
966 Turbine
967 Generator
981 Cylindrical wall lower end opening
982 Tangential entry duct air inlet
983 Tangential entry duct air outlet
987 Tangential entry duct inner wall
988 Tangential entry duct outer wall
991 Heat exchanger air inlet
992 Heat exchanger air outlet
Description—FIGS. 7 and 8
[0034] FIGS. 7 and 8 show plan and elevation views of a large Atmospheric Vortex Engine with the main tangential entry ducts 421 located inside the cylindrical wall 405. Cylindrical wall 405 has a lower end 461, an upper end 462, a large upper end opening 463 and a plurality of air openings 481 at the lower end. The complete system is called the “station” while the volume within the cylindrical wall 405 is called the “arena” 404. The cylindrical wall is a regular 20 sided polygon. The heat exchangers 401 shown in the figure are one sided wet cross-flow cooling tower but other types of heat exchangers such as counter-flow cooling towers or finned tubes could be used. Each heat exchanger 401 has a linear tangential entry duct 421 into arena 404. Each tangential entry duct 421 has an air inlet 482 and an air outlet 483. Each tangential entry duct has an inner wall 487 and an outer wall 488. Each linear tangential entry duct 421 can have air inlet flow restrictor 422, entraining steam jet 426, and outlet straightening vanes 425. Each heat exchanger 401 has an air inlet 491 and an air outlet 492. Each heat exchanger 401 air outlet 492 is connected to the air inlet 482 of the tangential entry duct 421 via opening 481 in the lower end 461 of the cylindrical wall 405.
[0035] Each heat exchanger 401 has an inlet turbo-generator 411 and can have an inlet forced draft fan 412. Turbo-generator 411 comprises turbine 467 driving a generator 468. Additional turbo-generators 415 can discharge directly in the tangential entry duct 421 without going through the cooling cell 401. Injecting steam in the tangential entry duct 421 with steam jet 426 is the preferred method of starting the vortex. Alternative vortex starting devices include: forced draft fans 412 in cooling cell inlets, or heating the air in arena 404 with fuel or steam. Cooling cells 401 operate at sub-atmospheric pressure because the air outlet is connected to the base of the vortex via linear tangential entry duct 421 and because the pressure at the base of the vortex is less than ambient pressure. The layer of air next to arena floor 403 acts as a channel because friction reduces tangential velocity in this layer and there is no similar tangential velocity reduction at higher levels. There can be friction enhancing devices including friction flaps, surface roughness, or small protrusions on arena floor 403. There can be a hump like hump 85 in FIG. 4 of U.S. Pat. No. 7,086,823, in the center of arena floor 403 to help keep the base of the vortex in the center of arena 404. The air velocity in the cooling cell 401 is limited by restrictions that can be part of turbo-generator 411 at the cooling cell 401 inlets and by restrictors 422 in linear tangential entry duct 421 at cooling cell 401 outlets to prevent excessive velocity from damaging the cooling cell fill 814 of FIG. 14. Air velocity across the fill is limited to approximately 3 m/s.
[0036] Cylindrical wall 405 could be 200 m in diameter by 100 m high. The number of cooling cells, ten in FIG. 7, is reduced for clarity. A 200 m diameter atmospheric vortex engine could have forty cells and each cell could have a 5 MW turbo-generator 411 for a total electrical power production of 200 MW.
[0037] There is a convergence roof 451 with a central opening 455 over arena 404. There is a circular underground room 441 at the center of the station; the underground room has a roof 442 with an opening 445 which can be adjustable. Linear tangential entry duct 421 is the main air entry into the arena 404, reverse rotation air entries 423 can be used to bring air with reverse rotation in the arena 404. The circulation of the air within the arena can be reduced or reversed by closing restrictors 422 in main tangential air entries 421 and opening reverse direction air entries 423.
[0038] The air rotation in a vortex engine can be clockwise or counter-clockwise. The direction of the rotation produced by main tangential entries 421 is called direct rotation. The direction of the rotation produced by reversed air entries 423 is called indirect rotation. In the figures the direct rotation has been shown as counter-clockwise; indirect rotation is therefore clockwise. In the northern hemisphere counter-clockwise rotation is cyclonic and clockwise rotation is anti-cyclonic. Direct rotation in a vortex engine can be either cyclonic or anti-cyclonic; there may be advantages in using one direction over the other but either should work.
[0039] Underground airways 431 and 434 can be used to let air in through station floor 403 tangentially at reduced radii. Underground airway 431 and 434 can have curved ends 432 that rise gradually, or can enter the circular underground room 441 tangentially. Underground airways 431 with direct rotation are used to help establish the vortex and can have steam injectors. Underground airways with reverse rotation, not shown, are used to stop the vortex and do not have steam injectors. Ambient air or warm humid air from the cooling cell 401 can be routed to the underground circular room 441 via tunnel 435. Only one tunnel 435 is shown; there could be a plurality of tunnels. Tunnel 435 can enter the circular room 441 tangentially as shown or radially. When the floor is elevated, see FIG. 16, airways 431 and 434 and tunnel 435 do not need to be underground. The term “under-floor” herein, is used to designate passageways, partitions, components and the like located under the floor, whether the floor is elevated or not.
[0040] Heat exchanger 401 is a wet cross-flow tower cooling cell. A cooling cell is a type of heat exchanger. Heat exchanger 401 has a warm water inlet 407 and a cooled water outlet 408. Water flow is described in more detail in the description of FIG. 13 and FIG. 14.
[0041] Transition rings 452, only one of which shown for simplicity, inhibit ambient air entrainment downward along the inside of the cylindrical wall 405. Entrainment of non-rotating ambient air can reduce vortex rotation. Inter-ring air entry 406 in the transition zone between rings permits the introduction of air with appropriate tangential velocity. Inter-ring air entries 406 can have restrictors and steam injection.
Operation—FIGS. 7 and 8
[0042] A vortex engine can operate with one or more cooling sectors in service. The vortex engine would be started by establishing the vortex with only a few sectors in service. There are many alternative ways of putting a vortex engine in service. A vortex engine would have a remote control room with a sophisticated control system capable of monitoring numerous process parameters and of manipulating valves and restrictors. For startup, the air inlets and outlets on the unused cells would be closed and the water flow to the unused cells would be closed. The vortex would be started by filling basin 55 in FIG. 4 of U.S. Pat. No. 7,086,823 or cooled water channel 736 in FIG. 13 with water possibly by pumping warm water through one of the startup cooling cells. The air flow through the starting cells would be started by injecting steam in their tangential entry ducts 421. Alternatively the air flow could be started by using forced draft fan 412 or underground intermediate tangential air entries 431. The quantity and quality of the steam would be controlled using steam valves and de-superheater water valves. Pressure would be monitored: at the center of the station, in the cooling cell and at other points. There could be video cameras to observe the vortex.
[0043] Establishing a vortex takes spin-up time. Once the vortex is established it may be necessary to quickly restrict the air flow to prevent damage to cell fill. The turbo-generators on the cell inlet would be then be started and brought up to load. The flow of air in each cooling cell would be monitored with flowmeters located either in the cell inlet or in the tangential entry duct. The water flow to each cooling cell and the temperature of the water entering and leaving the cells would be monitored. Once the vortex is established the additional cooling cells would be put in service by first establishing water flow and then air flow through the cell.
[0044] The pressure reduction at the base of the vortex would be monitored and the air flow would be restricted either at the cooling cell inlet turbine or in the tangential entry duct to keep the vortex at the desired intensity. The vortex would be stopped by reducing the direct air flow and if necessary opening reverse air flow.
Description FIGS. 9 and 10
[0045] FIGS. 9 and 10 show plan and elevation view of a circular cross-flow cooling tower with four heat exchangers (cooling cells) 301. These figures are for a small four cell cooling tower; the internal diameter of the arena 304 could be 50 m. Cylindrical wall 305 has an octagonal shape. Large circular forced draft cooling towers would have more cooling cells 301 and would be more circular in shape. The term “circular” should be interpreted to mean “not linear” and not “strictly circular”. Arena 304 is the volume within cylindrical wall 305.
[0046] Forced draft fans 326 on the air inlet of each cell push air through the cell fill; the warmed air enters arena 304 via radial entries 325. Convergence roof 340 located above the radial air entries 325 has a circular opening 342 at its center. Arena 304, the volume under the convergence roof 340, forms a manifold where air from a number of radial entries 325 joins together before exiting through common stack 346. Cooled water basins 350 are located under each cell 301. The cooled water pumps are located in extension 351 of two of the cooling tower water basins 350. The cooled water basins 350 are joined by underground equalizing lines 352.
[0047] Stack 346 above central opening 342 can have convergent and divergent sections. Stack 346 can be supported on thin posts. Solid stack 346 extends high enough to reduce fogging and recirculation. The buoyancy of the warm air in the nozzle reduces the energy required to push the air through the cooling towers. With a high enough stack it may be possible to turn off forced draft fan 326 once the flow has been established. Physical stack 346 can be a fabric tube with a restricted opening at the upper end.
Operation—FIGS. 9 and 10
[0048] The operation of the circular cooling tower is similar to that of a conventional cross-flow forced cooling tower. It is not necessary for all cells 301 to be in operation. Cells 301 that are not in service can be isolated with dampers located either in the inlet of forced draft fan 326 or in radial entry 325. The circular cooling tower is started by first establishing warm water flow and then establishing air flow. The cell 301 would operate at close to atmospheric pressure and the warm water distributor tray need not be within the cell. The water flow to the individual cells could be adjusted with valves. The air flow and the temperature of the water at the individual cells would be monitored and controlled by manipulating the speed or pitch of the forced draft fan.
Description—FIGS. 11 and 12
[0049] FIGS. 11 and 12 show plan and elevation views for a forced draft circular cooling tower capable of operating in vortex or non-vortex mode. Forced draft fans 526 push the air through heat exchanger (cooling cell) 501 and up through opening 541 in arena roof 540. Cylindrical wall 505 extends higher than cylindrical wall 305 of FIG. 10; stack 346 of FIG. 10 is not required.
[0050] The circular cooling tower can be switched from non-vortex mode to vortex mode by opening tangential entries 521 and by closing radial entries 525. Tangential entry 521 and radial entry 525 have restrictors. Restrictors could be rotating vanes. The rotating vanes in the tangential entry 521 could rotate in opposite direction about the horizontal axis. The rotating vanes in radial entry 525 could rotate in the same direction about the vertical axis to permit admitting air in the arena either radially or with reverse rotation. Alternatively radial entries 525 could be closed with removable panels when there is no need to operate in non-vortex mode. Restrictors at the inlet of forced draft fan 526 and in tangential entry duct 521 prevent the air flow from getting too large when the vortex mode becomes established.
[0051] There are cooled water basins 550 under each cell 501. The cooled water pumps are located in basin extension 551 of two of the cooling tower water basins. The cooled water basins are joined by underground equalizing lines 552.
Operation—FIGS. 11 and 12
[0052] This circular cooling tower can be designed to operate in one-mode or two-modes. In the one-mode model the unused air entry, either radial entry 525 or tangential air entry 521, would be closed with removable panels. The non-vortex mode would be a backup in case the owner does not want to operate in the vortex mode. Operation in the non-vortex mode would be similar to the operation of the non-vortex circular cooling tower of FIGS. 9 and 10. Operation in the vortex mode would be similar to the operation of the vortex cooling tower of FIGS. 7 and 8.
[0053] In the two-mode model, the mode would be switched from non-vortex to vortex by gradually closing radial entries 525 with vanes rotating about the vertical axis and gradually opening tangential entries 521 with rotating vanes. It may be necessary to reduce the flow in some of the cells 501 during the transition.
Description—FIG. 13
[0054] FIG. 13 shows a plan view of a vortex engine where the air inlet is not interrupted by gaps between cooling cells. The vortex engine has a uninterrupted front face 704. In FIGS. 7 and 11 every second side of the polygonal cylindrical wall has a cooling cell. In FIG. 13 every side of the polygon has a heat exchanger. The absence of gaps between heat exchangers reduces cooling tower cost. It is economically advantageous for circular vortex engine to have uninterrupted face and to have a heat exchanger on every side of the polygon.
[0055] Ambient air enters the heat exchanger 706 through turbine 712. Warmed air enters cylindrical wall 702 via opening 781 at the lower end of cylindrical wall 702 and via linear tangential entry duct 714. Linear tangential entry duct 714 has an air inlet 782 and an air outlet 783. The area within cylindrical wall 702 has a convergence roof 716 with a circular opening 718 at its center. Warm water enters the top of heat exchanger 706 via warm water inlet pipe 732. Cooled water from the cooled water collector located under the heat exchanger drains to open circular channel 736 via underground cooled water pipe 734. The cooled water flows to pump sump 738 whence it is pumped to through process coolers before returning to heat exchanger 706 via warm water inlet pipe 732. Circular cooled water channel 736 is an alternative to cooled water basin 55 of FIG. 4 of U.S. Pat. No. 7,086,823 located under the cooling cell. Circular water channel 736 facilitates the use of shared cooled water pumps located in sumps 738 away from the heat exchangers 706.
Operation—FIG. 13
[0056] The cooling tower of FIG. 13 operates similarly to the cooling tower of FIGS. 7 and 8.
Description—FIG. 14
[0057] FIG. 14 shows a side view of a heat exchanger 804. Heat exchanger 804 of FIG. 14 is a wet cross-flow cooling tower cell and is referred to as a cooling cell in the following description. Cooling cell 804 abuts the outside of cylindrical wall 802. Cooling cell 804 has a sub-atmospheric enclosure 807. Ambient air enters cooling cell 804 through turbine 850 which drives generator 852. Turbine 850 has an air inlet 865 and an air outlet 866. Perforated baffle 854 distributes the air evenly across the face of the cell fill 814. Air flows horizontally through fill 814; entrained liquid is separated from the warmed air by drift eliminators 818. The fill 814 slopes inwardly to correspond to the pull back drag effect of the air on the falling water. Inlet louvers 816 bring water not dragged sufficiently by the air flow back towards fill 814. The warmed air enters the arena via tangential entry 856. Convergence roof 858 forces the warm air to converge before it can rise.
[0058] Cooling cell 804 has an air inlet wall 805 and an air outlet wall 806. The outside of cylindrical wall 802 serves as the outlet wall 806 of cooling cell 804. Linear tangential entry duct 856 is inside cylindrical wall 802. The inside of cylindrical wall 802 serves as the outside wall of tangential entry duct 856. The air outlet of cooling cell 804 is connected directly to the air inlet of linear tangential entry duct 856 through an opening in cylindrical wall 802. Tangential entry duct 856 is parallel to the side of polygonal cylindrical wall 802 adjacent to the side along which associated cooling 804 cell abuts. Heat exchanger 804 has an air inlet 891 and an air outlet 892.
[0059] Warm water enters cooling cell 804 via warm water pipe 810. The warm water then goes to warm water distributor tray 812. Warm water distributor tray 812 is similar to the warm water distributor tray in conventional cross-flow cooling tower. Warm water distributor tray 812 has a large number of cross-flow nozzles 813 on its bottom. Cross-flow nozzles 813 are widely used in cross-flow cooling towers. There could be over one thousand cross-flow nozzles per warm water distributor tray. The cross-flow nozzles 813 are located on a grid approximately 30 cm apart. The cross-flow nozzles 813 could have an internal diameter of 1 to 2 cm and a built-in target downstream of the nozzle to breaks up the water jet into small droplets. The water level in distributor tray 812 could be 2 to 20 cm. The flow through cross-flow nozzles 813 depends on the pressure difference between cross-flow nozzle 813 inlet and cross-flow nozzle 813 outlet. Cross-flow nozzle 813 pressure difference is affected by both the water level in distributor tray and by the difference in pressure between the top and bottom of distributor tray 812. Warm water distributor tray 812 must be located within sub-atmospheric enclosure 807 to ensure that the pressure on the top and bottom of warm water distributor tray 812 are the same and that cooling cell 804 pressure does not affect warm water flow through the cross-flow distributor nozzles 813. With equal pressures on the top and bottom of warm water distributor tray 812, the only factor affecting water through cross-flow nozzles 813 is the height of water in warm water tray 812.
[0060] In FIG. 4 of U.S. Pat. No. 7,083,823, warm water distributor tray 53 is located outside sub-atmospheric pressure enclosure 23. While ambient pressure is typically 100 kPa the pressure in the cooling cell 61 can vary between 100 and 80 kPa. With the distributor tray outside sub-atmospheric enclosure 61, the effect of small changes in cooling cell pressure on cross-flow nozzles 813 flow can be greater than the effect of the water level in distributor tray 53. For this reason the warm water distributor 812 tray must be within cooling cell 804. Installing warm water distributor tray within cooling cell 804 ensures that cross-flow nozzle 813 flow is only a function of the water level in distributor tray 812 and that flows in the cross-flow nozzle are independent of cooling cell 804 pressure.
[0061] Cooled water drains from the collection area at the bottom of cooling cell 804 through drain pipe 820 and flows to open cooled water channel 824. The water level in cooled water channel 824 is approximately one meter higher than the top of cooled water pipe 820. The water level in cooled water channel 824 forms a seal 822 preventing ambient air from entering the cooling cell via cooled water drain 820. Water level in drain pipe 820 is slightly higher than in cooled water channel 824 because the pressure in the cooling cell is sub-atmospheric. The elevation of the floor of the arena 842 is close to grade 840. The water level in channel 824 is maintained at a few meters below grade 840 and approximately one meter above the top of drain pipe 822. Cooled water pump 826 driven by motor 828 circulates the cooled water via pipe 830. The cooled water inventory of the cooling system is mainly held in circular cooled water channel 824 and its pump sump 738 in FIG. 13.
Operation—FIG. 14
[0062] The tower of FIG. 14 operate's similarly to the tower of FIGS. 7 and 8.
Description—FIGS. 15 and 16
[0063] FIGS. 15 and 16 show plan and elevation views of a vortex cooling tower with an elevated floor 903. Under-floor plenum 906 can be used to route starting air tangentially at intermediate radius in lieu of underground airway 431 of FIGS. 7 and 8 or to route air to the center of the vortex in lieu of underground tunnel 435 of FIGS. 7 and 8. Underground plenum 906 can be divided into compartments with radial walls or can be an open space except for support columns. FIGS. 15 and 16 show the preferred embodiment.
[0064] Vertical axis cylindrical wall 905 is polygonal in shape, has a lame opening 963 at the top end 962, and a multiplicity of small openings 981 at the lower end 961. The station has a multiplicity of heat exchangers 901 which in the figure are one-sided wet cross-flow cooling cells. Each heat exchanger 901 has a tangential entry duct 921 into arena 904. Each heat exchanger 901 has an air inlet 991 and an air outlet 992. Heat exchanger air outlet 992 is connected to air duct air inlet 982 via via opening 981 at lower end 961 of cylindrical wall 905. Tangential entry duct 921 has an inlet end 982 and an outlet end 983. Tangential entry duct has an inner wall 987 and an outer wall 988. Tangential entry ducts 921 have adjustable inlet flow restrictors 922, entraining steam jets 925, and can have outlet straightening vanes not shown. Each cooling cell has an inlet turbo-generator 911 and can have an inlet forced draft fan not shown.
[0065] The cylindrical wall could be 200 m in diameter by 100 m high. A 200 m diameter atmospheric vortex engine could have 40 cells and each cell could have a 5 MW turbo-generator 911 for a total electrical power production of 200 MW. Turbo-generator 911 comprises turbine 966 driving generator 967.
[0066] There is a convergence roof 951 with a central opening 955 over arena 904. Tangential entry ducts 921 are the primary air entry into arena 904. The air circulation within arena 904 can be reduced by closing main restrictors 922 and opening reverse direction restrictors 927. Intermediate radius air entries 932 in elevated floor 903 can be used to let in air from plenum 906 enter arena 904 tangentially at reduced radii. Intermediate radius tangential entries 932 can have direct rotation to help establish the vortex or can have reverse rotation to help stop the vortex. Intermediate radius entries with direct rotation can have steam injectors.
[0067] Under-floor circular room 941 located at the center of the station has a roof 942 with a circular opening 945. Opening 945 can have an adjustable diameter. Warm humid air from the cooling cell can be routed to the under-floor plenum 906 via restrictors 916. Ambient air can also be routed to floor opening 945 without going through cooling cell 901 via under floor plenum 906, not shown. The ambient air can go through turbines located upstream of plenum 906. There can be a peripheral wall 917 with air entries between plenum 906 and circular room 941. Alternatively 917 can be a ring of adjustable deflectors allowing air to be directed tangentially or radially. Alternatively peripheral wall 917 can be omitted.
[0068] Heat exchanger 901 has a warm water inlet 907 and a cooled water outlet 908. Water flow is described in more detail in the description of FIG. 13 and FIG. 14.
[0069] Transition rings 952 inhibit ambient air entrainment downward along the inside of the cylindrical wall. Inter-ring air entry 953 in the transition zone between convergence roof 951 and transition rings 952 permits the introduction of air with appropriate tangential velocity. Inter-ring air entries 953 can have restrictors and steam injection.
New Elements
[0070] U.S. Pat. No. 7,086,823 described a generic vortex engine. The present specification describes enhancements to the original invention and new combinations of elements. This New Element section describes the new features.
(a) Linear Tangential Entry Duct
[0071] Linear tangential entry ducts 921 of FIG. 15 are an improvement over tangential entry deflectors 103 of FIG. 1 of U.S. Pat. No. 7,083,823. The angle of entry of the air in the arena can be closer to tangential with ducts than with deflectors. Achieving entry as tangentially as possible with deflectors requires a large number of deflector vanes per cooling cell. The linear entry duct approach only requires one duct per cooling cell. The deflector approach requires a multiplicity of vanes for each cooling cells. Accessories such as steam jet 925 and restrictors 922 of FIG. 15 have to be duplicated for each deflector while they are only required once per cooling cell with linear tangential entry ducts.
[0072] The linear tangential entry ducts are located inside the cylindrical wall. The straight sides of the polygonal cylindrical wall permit having straight entry ducts. The duct is located along the inside of the polygon. The air outlet of the heat exchanger is connected directly to the air inlet of the linear tangential entry duct via an opening in the cylindrical wall.
[0073] Internal linear tangential entry ducts arrangement have several advantages:
1. Makes possible angle of entry closer to tangential.
2. A large number of deflector vanes would be required to achieve the same tangential entry result as can be achieved with a single linear tangential entry duct.
3. Locating the tangential entry duct on the inside of the cylindrical wall and the cooling cell on the outside of the cylindrical wall minimizes the length and cost of the duct.
4. A polygonal cylindrical wall permits the use of straight tangential entry ducts.
5. Restrictor can be provided within the entry duct.
6. There can be more than one device for blocking the duct to ensure that the air flow to the arena can be shut off to stop the vortex in an emergency.
7. Steam can be injected in the duct to entrain and heat the air, thereby initiating the vortex.
8. The turbulence in the air entering the arena can be reduced by providing straightening vanes or perforated screens within the duct.
9. The velocity of the air entering the arena can be manipulated by adjusting the cross sectional area of the duct.
10. Closing the duct provides a way of servicing the equipment upstream of the duct, namely the cooling tower and the turbine, without stopping the vortex.
11. The air circulation in the arena can be reversed by closing the direct entry air entry via the tangential entry duct and by opening air entries with reverse circulation.
12. The tangential entry duct can be divided in a lower and an upper part, wherein the lower part is used to bring air next just above floor level, and wherein the upper part is used to bring in air at higher level.
13. The invention can be operated in non-vortex mode by closing the tangential entries and by opening radial entries.
(b) Floor Central Opening
[0087] There can be a circular opening in the center of the arena floor whereby air can be routed to the center of the vortex. The diameter of the opening can be adjustable. Ambient air or warm air from the heat exchangers can be routed to the central floor opening via underground tunnels or via a plenum under an elevated floor. The quantity of air entering the vortex via the central air entry can be controlled with restrictor.
(c) Under-Floor Circular Room
[0088] There can be a circular room under the floor central opening. There can be a ring of deflectors around the periphery of the circular room whereby the tangential velocity of the air can be controlled. The air can thus enter the circular room either tangentially or radially. Admitting air radially in the center of the vortex eliminates centrifugal force thereby increasing turbines differential pressure and mechanical energy production.
[0089] In U.S. Pat. No. 7,086,823 the angle of entry of the air in the arena is controlled by adjusting deflector orientation or by selecting deflectors with the appropriate orientation. In U.S. Pat. No. 7,086,823 the air entering the arena via the upper deflectors can have a more tangential angle of entry than the air entering the arena via the lower deflectors. In the present specification the tangential velocity of the air entering the arena is maximized through the use of tangential entry ducts. In both U.S. Pat. No. 7,086,823 and in the present specification the tangential velocity of the air immediately above the floor can be reduced by surface friction, by surface roughness or by surface friction flaps. In the present specification the tangential velocity of the air in a lower entry level can be eliminated by routing air to the center of the vortex via a floor central opening. In the present specification the tangential velocity profile is controlled by varying the flow distribution between the tangential entry duct and the central floor opening.
(d) Elevated Floor
[0090] The surface under the vortex, called the floor, is a very important element in a convective vortex because tangential velocity is reduced by friction more next to the floor than at higher elevation. At higher elevation the horizontal pressure gradient is balanced by centrifugal force. The reduced centrifugal force next to the floor makes it easier for the air to converge next to the floor than higher up. As a result air convergence occurs mainly in the layer next to the floor. Convergence can be enhanced by increasing the roughness of the floor surface or by providing friction enhancing devices such as: a rough surface, friction flaps or small protrusions on the floor. The floor of a vortex engine can be at grade as shown in FIG. 8 floor 403 or can be elevated as shown in FIG. 16 floor 903.
[0091] An elevated floor has the following advantages:
1. The air entering the arena comes preferentially from the upper part of the cooling cell where the air is warmest.
2. The downward distance air from the top of the heat exchanger has to travel to get to the vortex floor is reduced.
3. The requirement for providing guide vanes to prevent the air from being taken preferentially from the bottom of the cooling cell is reduced.
4. The area under the elevated floor can serve as a plenum for routing air to the central room.
5. Warm air from the cooling cells can be routed radially to the center of the vortex via the under-floor plenum by closing the tangential entry duct and opening adjustable restrictors between the cooling cell and the under-floor plenum.
6. Turbine exhaust can be routed to the center of the vortex via the under-floor plenum with or without going through cooling cells.
7. Radial entry in the center of the vortex via the under-floor plenum eliminates centrifugal force and increases the differential pressure available at the turbine.
8. The cost of a concrete elevated floor is less than the cost of a multiplicity of underground ducts and tunnel.
9. The under-floor plenum can be divided into compartments separated by radial wall or left open except for the columns required to support the floor.
(e) New Vortex Cooling Tower Features
[0101] The preferred heat exchanger is a single sided cross-flow cooling tower. The cooling tower differs from normal cross-flow cooling tower in that it operates at sub-atmospheric pressure. The cooling tower has a warm water distributor tray with distributor nozzles at the top and can have a cooled water basin at the bottom (FIG. 4 basin 55, of U.S. Pat. No. 7,086,823). Alternatively the cooled water can drain to a peripheral circular channel via a water seal (FIG. 13 channel 736, FIG. 14 channel 824). The warm water distributor tray is located within the sub-atmospheric enclosure to provide a constant differential pressure across the distributor tray nozzles. The annular warm water basin extends radially outward from the cooled water basin. The fill slopes inward from top to bottom to match pull back of the falling water by the air flow. The front face of the cooling tower has louvers to catch any water not pulled back by the air flow and return it to the cold water basin. The fill can be splash bar type or film type. Drift eliminators downstream of the fill remove entrained water droplets and return them to the cooled water basin.
[0102] The fill with associated inlet louver, drift eliminators, warm water distributor basin, cooled water basin, and drift eliminator and their enclosure, is called the “cooling cell”. A cooling cell with associated turbo-expander, optional forced draft fan, and tangential entry duct is called a “sector”. An ensemble of cooling cells including the cooled water pumping system is a “cooling tower”. A circular cooling tower with a vortex at its center is a “vortex cooling tower”. The generic term “Atmospheric Vortex Engine” designates the device for producing a convective vortex. The heat exchanger and the turbines are not essential to an atmospheric vortex engine. The heat exchange means is not required when the ambient air has sufficient temperature and humidity. When there is no heat exchanger, the turbines exhaust directly into the tangential entry duct.
[0103] Atmospheric vortex engine cooling cells must be fully enclosed to permit operation at sub-atmospheric pressure. Cooling cells require an inlet wall not present in conventional cross-flow cooling tower. Air enters the cooling cell through an opening in the cell air inlet wall. Inlet baffles distribute the air evenly over the louvered face of the fill. Warm-humid air exits the cooling cell via the tangential entry duct. The tangential entry duct is inside of the cylindrical wall. The tangential entry duct of a cooling cell runs along the adjacent side of the polygonal cylindrical wall. Guides vanes may be provided to ensure that the air entering the tangential entry duct is taken form all levels of the cooling cell. There can be additional adjustable air entries from the cooling cell to the arena. These additional air entries may be radial air entries or reverse rotation air entries.
[0104] It is not necessary for all sectors to be in service. Sectors can individually be taken out of service by closing their tangential entry duct. A cooling cell and its turbine can be taken out of service by closing its warm air outlets, by shutting off its water inlet, and by opening its air inlet.
[0105] The sectors must be separate on the air side and on the water side. There must be seals on the cooled water side to prevent air from traveling between cells. The seal can be achieved by a variety of methods including:
[0000] (a) extending the inter cell wall to the bottom of the cooled water basin (FIG. 4 air seal wall 49 of U.S. Pat. No. 7,086,823),
(b) providing a water seal by having the cooled water enter a cooled water channel below the water level in the cooled water channel (FIG. 14 cooled water seal 822),
(c) forcing the cooled water from the cooling cell flow down through an upright “U” located upstream of the cooled water channel, not shown.
[0106] The preferred cooled water system replaces the conventional cooled water basins located under cooling cells with a sloped cooled water collection floors. The cooling cell floors drain to the open circular cooled water channel via underground pipes. The water in the channel forms a seal and prevents air from entering the cooling cells via the cooled water return. The cooled water flows to a sump where the circulating water pumps are located. The inventory of cooled water is mainly in the circular cooled water channel and in the sump.
[0107] Air must be prevented from entering the cooling cells via the cooled water return because the pressure in the cooling cells is lower than atmospheric pressure. The water level in the channel should be high enough above the top of the cooled water pipe to prevent air from entering the individual cell through the cooled water outlet. The water level in the circular channel is controlled with conventional cooling towers makeup techniques. There can be more than one pump basin permitting sections of the circular cooled water channel to be taken out of service for maintenance without stopping the vortex. The circulating water does not normally enter the arena. There would be drains at low points in the arena to remove water that may inadvertently enter the arena.
(f) Convergence Roof
[0108] The atmospheric vortex engine and the circular cooling tower can both have a convergence roof with an opening in its center above the main air entry. The diameter of the opening at the center of the roof can be adjustable. In the vortex mode, the convergence roof creates a convergence area wherein tangential velocity must increase as the air converges in order to conserve angular momentum. In the non-vortex mode the convergence roof serves to bring the multiplicity of cooling tower air outlets together in a single plume. In a non-vortex circular cooling tower, there can be a stack above the convergence roof opening.
[0109] Convergence roof 951 of FIG. 16 is similar to the annular roof 11 of FIG. 4 in parent specification U.S. Pat. No. 7,086,823 but the purpose is different. The purpose of the parent patent annular roof was to keep the air entering through the lower and upper levels of deflectors separate. The parent specification annular roof had to be located immediately above the lower deflector 3 of FIG. 4 of U.S. Pat. No. 7,086,823. The purpose of the new convergence roof 951 of FIG. 16 is to force convergence thereby forcing tangential velocity to increase in order to conserve angular momentum. Convergence roof 951 of FIG. 16 can be a distance above the top of tangential entry ducts 921.
[0110] While the convergence roof is shown flat in the figures, it can have other shapes, including:
[0111] a constant upward slope from rim to central opening,
[0112] a nozzle consisting of an increasing upward slope from rim to central opening,
[0113] a dome with a central opening.
(g) Transition Rings
[0114] An atmospheric vortex engine can have a plurality of transition rings between the main convergence roof and the top of the cylindrical wall. The vortex transitions from a confined vortex to a free vortex as it moves up from the opening in the convergence roof to the free atmosphere. Transitions rings ease the transition. The transition rings reduce the quantity of ambient air entrained downward along the inside of the cylindrical wall. Entrainment of ambient air in the vortex can reduce angular velocity. There can be tangential air entries between the convergence roof and the transition ring and between transition rings to provide air with rotation for entrainment in the vortex during the transition. These inter-ring air entries can have restrictors and steam injection.
(h) Entraining and Heating Steam
[0115] There are several options for starting the vortex:
1. Using steam jets in the tangential entry duct to entrain air into the arena while heating and humidifying the air.
2. Heating the air within the arena with fuel or steam,
3. Pushing the air through the tangential entries with forced draft fans located at the cooling tower inlets or outlets.
[0119] Steam jets in the tangential entry duct are the preferred starting method because steam is usually available at cooling tower sites and because steam injection equipment is less costly to purchase and maintain than fans. The steam can be superheated to make the mixture invisible or water can be injected in the steam in a de-superheater to make the vortex visible.
(i) Intermediate Radii Floor Tangential Air Entries
[0120] Intermediate radii air entries can introduce air tangentially through the arena floor. The air could be brought to the intermediate radii floor tangential air entries via underground airways or via air plenum located under an elevated floor. Underground airways could enter the arena tangentially and could have a curved rising section at their downstream end. The curved section would rise gradually over an arc of roughly 30 to 120 degrees. Intermediate radii floor air entries could have direct and indirect rotation. There would be devices for controlling the air flow in the floor air entries. The intermediate radii floor tangential air entries with direct rotation could have steam jets. Starting a vortex with air entry at the cylindrical wall only can require a long spin-up time. Introducing air with direct rotation tangentially at intermediate radii would help start the vortex by reducing spin-up time. Airways with indirect rotation would be used to help stop the vortex and would not have steam injection.
(j) Non-Vortex Circular Cooling Tower
[0121] Cooling towers with fans are called “mechanical cooling towers”. The fans in mechanical cooling towers can be in either of two locations. Forced draft cooling towers have their fans in the air inlet, usually at grade. Induced draft cooling towers have their fans in the air outlet, normally at the top of the cooling tower. Induced draft cooling tower are more common than forced draft cooling towers because the low exit-velocity of cooling tower with forced draft towers results in fogging and recirculation. Fans in induced draft cooling towers are invariably vertical axis axial flow fans. Fans in forced draft cooling towers are usually horizontal axis centrifugal blowers.
[0122] There are two ways of contacting the air and the water. In counter-flow tower the water flows down and the air flows up. In cross-flow towers the water flows down and the air flows horizontally across the falling water.
[0123] The cooling cells of mechanical cooling towers can be arranged in linear or circular arrays. Mechanical circular cooling towers usually have a plurality of top mounted induced draft fans. A circular arrangement reduces recirculation and fogging because a single large plume retains its buoyancy longer than a multiplicity of small plumes, and because the circular shape alleviates recirculation on the downwind side by allowing the wind to flow around the tower.
[0124] Mechanical circular cooling towers usually have induced draft fans. Mechanical circular cooling towers were developed after the advantage of induced draft fans over forced draft fans had been demonstrated in linear cooling towers. The idea that a circular cooling with a central air outlet could permit reverting to the earlier forced draft fan approach does not seem to have been considered.
[0125] The fans in the circular cooling tower of the non-vortex circular cooling tower can be located in: the cooling cell outlet, in the cooling cell radial outlet, or in the tangential entry duct, but not in the combined cooling tower outlet. Locating the fans in the combined outlet would preclude having a single large plume. Locating the fans in the air inlet to the cooling cell as shown in FIG. 9 fan 326 is the preferred arrangement. Fans located at the cooling cell inlets have the following advantages: fans are easily accessible for maintenance, the fan position is suitable for either non-vortex or vortex mode. Fans located at cooling cell outlets eliminate the need for entrance walls and their resistance to flow, but are less easily accessible.
[0126] Fans in induced draft circular cooling towers are grouped together at the top of the tower. The fans can be grouped in the center of the tower or can be located on the periphery of a circle located inward of the heat exchange area. The need for a multiplicity of fans and for horizontal spacing between fans increases plume diameter, reduces average plume upward velocity, and increases opportunity for entrainment of surrounding air into the plume. Circular cooling tower technology is described in U.S. Pat. No. 3,743,257 by Fordyce.
[0127] U.S. Pat. No. 4,164,256, by Kelp, describes a counter-flow natural draft cooling tower with forced draft fans. There are stubby fan assisted natural draft cross-flow cooling towers that have vertical axis fans grouped at the top of a central area. Circular wet cooling towers comprising: cross-flow cells, forced draft fans at individual cell inlets or horizontal axis fans at individual cell outlet, and a central stack significantly smaller in diameter than the inner diameter of ring of cooling cells have not been used.
[0128] A circular cooling tower with fans at cooling cell inlets or outlets has the following advantages:
1. The single large plume retains its buoyancy longer than a multiplicity of small plumes.
2. Circular cooling towers cause less fogging and recirculation than linear cooling towers because their shape provides less opportunity for recirculation. In circular cooling towers the plume is carried down wind and away from the tower; in linear cooling tower the tower blocks cross wind causing recirculation.
3. The cross-flow cooling cells exhaust radially in the central arena.
4. A convergence roof with a circular opening at its center brings the air outlet from a multiplicity of cooling cell together into a single large plume.
5. A stack, similar to the cylinder of an induced draft fan, can be provided above the central opening. The stack reduces entrainment of ambient air in the plume. The stack reduces fogging by raising the base of the plume. The upward velocity of the air at the outlet of the stack would be comparable to the outlet velocity of individual induced draft fans and higher than the average upward velocity of grouped induced draft fans. The stack raises the base of the plume thereby reducing fogging and recirculation.
6. The buoyancy of the air rising in the stack assists the forced draft fans in producing circulation thereby reducing the fan power requirement. The fans can be turned off when not needed such as in cold weather or at low cooling loads.
7. The stack could be a tall fabric tube. The fabric tube could be slipped over a short physical stack and raised gradually. The size of the opening at the upper end of the fabric tube could be adjustable. The fabric tube would be raised by blowing air in the tube with the forced draft fans. The fabric tube could extend higher than a physical tube and could be less costly. The fabric tube could be fabricated of sail material such as Dacron or nylon.
8. Forced draft fans located at ground level do not require the strong supporting structure required for induced draft fans thereby reducing structure cost. Supporting induced draft fans located near the center of a circular cooling tower requires a sophisticated and costly structure.
9. Induced draft circular cooling towers with a single fan are impractical because of the limitation on fan size. A forced draft circular cooling tower permits combining the flow from a multiplicity of forced draft fans in a single large plume. The stack could be 20 to 50 m in diameter.
10. The circular cooling tower can be provided with both radial air entries and tangential air entries ducts permitting the mode of operation to be switched from non-vortex to vortex mode by closing radial entries and opening tangential entries.
11. In the vortex mode the fans are only required for startup and can be turned into a power producing turbines once the vortex has been established.
12. A forced draft circular cooling tower can be a useful and economical device by itself without the use of the vortex mode.
Thermodynamic Basis
(a) Troposphere as a Heat Sink
[0141] Thermodynamic or thermal engines are devices wherein heat is converted to work. A solar engine is a thermal engine wherein the heat source is the sun. Thermal engines function by converting a fraction of the heat or thermal energy transported from a hot source to a cold source to mechanical energy. The cold source is commonly called the cold sink or simply the sink. The fraction of the heat input converted to work called the efficiency increases with the temperature difference between the heat source and the heat sink. The maximum possible efficiency of a thermal engine is the Carnot efficiency (n) defined as
[0000]
n=1−(Tc/Th)
[0000] where Th and Tc are respectively the temperatures of the hot source and of the cold source in degrees absolute. The Carnot efficiency of an engine with a hot source temperature of 300 K (27° C.) and a cold source temperature of 240 K (−33° C.) is 20%. Carnot efficiency can be increased by increasing hot source temperature or by decreasing cold sink temperature. The heat sink temperature for the vast majority of thermal engine is the lowest temperature available at the engine location which is usually close to the temperature of the air or water at the engine location.
[0142] Carnot efficiency is merely the maximum possible efficiency for a given temperature difference. The actual efficiency of an engine is typically significantly lower than the Carnot efficiency. Thermal engines require that the heat be transported in a process involving compressing and expanding a gas or a vapor. The efficiency reduces to near zero if the heat is transported by conduction, by convection with a liquid, or by gaseous convection without the use of an expander.
[0143] The troposphere is the bottom 10 to 20 km of the atmosphere, the layer of the atmosphere wherein temperature normally decreases with height. Temperature in the troposphere typically decreases in the upward direction by about 6 K/km. The temperature at the bottom of the troposphere is typically 290 K. The temperature at the top of the troposphere is typically 220 K. The troposphere radiates heat to space at an average temperature of around 250 K. Radiation to space cools the troposphere by roughly 1 to 2 K/day. The bottom layer of the troposphere is called the boundary layer and typically extends from the earth's surface to the level of the bottom of fair weather cumulus which is typically at the 0.5 to 3 km level.
[0144] The invention is described using the term “lower troposphere” to designate the bottom 1000 m of the atmosphere, and the term “upper troposphere” to designate the atmosphere above the 1000 m level. The invention involves transferring heat from the lower layer of the troposphere to the upper layer of the troposphere. Using the troposphere as a heat sink can provide a lower heat sink temperature than simply using the air at the bottom of the atmosphere. Using the high troposphere as a cold sink has not been considered previously because it is generally considered impractical either to bring the cold air down or to bring the fluid to be cooled up.
[0145] A thermal engine involves: transferring heat to the hot source, transferring heat away from the cold source, and transporting heat from the hot source to the cold source. The work is produced when the heat is transported from the hot source to the cold source and not necessarily when the heat is received by the hot source or given up by the cold source. In most engines the three processes occur simultaneously, but they need not be simultaneous. Simply adding heat to or removing heat from reservoirs does not produce the work. Transporting heat from the hot source to the cold sink with an engine is what produces work. There is no need for the heat transfer to occur at the same time as the heat transport. The heat transported by the atmospheric vortex engine can be accumulated in the boundary layer over a long period of time and the radiation to space from the cold upper troposphere can occur long after the upward heat transport and can take place far away from where the upward heat transport occurred. The raised air can be cooled gradually by radiation to space as it subsides.
[0146] The availability of a cold source significantly colder than the temperature at the bottom of the atmosphere makes it possible to produce work from low temperature heat sources such as natural warm humid air. The vast majority of thermal engines use gas or vapor to transfer heat from the hot source to the cold source. Gas and vapor engines are typically comprised of compressors and expanders. Compressors and expanders typically have efficiencies in the 80% to 95% range which reduce the overall cycle efficiency. Compressing a low density gas requires huge machines and is very costly. In the atmosphere subsiding air is compressed as it descends. The efficiency of this atmospheric compressor can be close to 100%. There are virtually no friction loss as the slowly subsiding air descends. When air is compressed its temperature increases. The temperature increase when air is compressed through atmospheric subsidence is lower than the temperature increase when air is compressed in a conventional compressor because there is less friction and because heat is radiated to space during the compression process. Air typically takes approximately 30 days to subside from the top to the bottom of the troposphere while being cooled by radiation to space. Without radiation to space, the subsiding air would have a temperature of 340 K when it would reach the bottom of the atmosphere. With radiation to space the subsiding air has a temperature of around 290 K at the bottom of the atmosphere.
[0147] Industrial processes using the troposphere as the cold sink, include:
Solar chimneys,
Natural draft cooling towers,
Aircraft engines (reciprocating and jet engines),
The atmospheric vortex engine.
[0152] Natural draft cooling towers have been used to avoid having to supply mechanical energy to drive fans but have not been used to produce energy. The mechanical energy produced by aircraft engines must be used locally and can not be transmitter to the ground. The solar chimney is the only existing process capable of producing mechanical energy at a fixed ground based location. Solar chimneys higher than 1 km are not presently practical and therefore solar chimneys can not make use of the part of the troposphere above 1 km as a heat sink. The atmospheric vortex engine is the only stationary engine that can use the upper troposphere as a heat sink. The efficiency increases with height as cold sink temperature decreases. The maximum efficiency of a 200 m high solar chimney is 0.7%. The maximum efficiency of a vortex engine where the vortex extends to a height of 20 km could be up to 30%. The atmospheric vortex engine is the first practical method of using the extremely cold upper layers of the troposphere as a heat sink.
(b) Unaltered Natural Heat Collector
[0153] Engines, which produce mechanical energy in the form of shaft work, usually require a temperature differential of well over 100° C. Convective processes such as natural draft cooling towers, reboilers and coffee percolators, which do not usually produce shaft work, operate with lower temperature differential. Since the cold source temperature is normally the temperature at the bottom of the atmosphere, the minimum hot source temperature for engines that produce shaft work is usually well over 100° C. Engines producing shaft work usually require a minimum working fluid temperature of over 100° C. at the start of the expansion process.
[0154] The working fluid in the atmospheric vortex engine is warm humid air. The work produced when air is raised depends on both the temperature and the humidity of the air. Enthalpy is a measure of the combined heat content of air. The enthalpy of air with 100% relative humidity at 30° C. is higher than the enthalpy of 40° C. air with 40% relative humidity. Water at 30° C. can be used to increase the heat content of [[with]] low humidity air or low temperature air. The use of water as the heat source further increases the ability to use low temperature heat sources. Water at 30° C. can be used to increase the enthalpy of 40° C. air.
[0155] By using the upper troposphere as the cold source, the atmospheric vortex engine is able to use a hot source close to the temperature at the bottom of the atmosphere. The availability of a low temperature heat sink makes possible the use of low temperature heat sources including the use of working fluid having temperatures close to the temperature at the bottom of the atmosphere at the start of the expansion process. The atmospheric vortex engine is the only thermal engine that can use hot sources at temperatures of less than 50° C. to produce shaft work with heat to work conversion efficiencies of 5% or greater. The atmospheric vortex engine is the only solar engine wherein the Earth's land and sea surface in their unaltered state can be used as the heat collector.
[0156] The cost of solar collectors alone prevents solar engines from being competitive with conventional power sources. The atmospheric vortex engine can eliminate the need for the costly solar collector. Through the use of a low temperature heat sink, the atmospheric vortex engine eliminates the need for the solar heat collector. The atmospheric vortex engine is the only solar engine that can use the earth's surface in its unaltered state as a solar heat collector.
Alternatives Arrangements
[0157] While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the claims.
[0158] It is not necessary that each sector have a heat exchanger with a tangential entry into the arena and an entry in the plenum. In FIGS. 15 and 16 each heat exchanger 901 has a tangential entry 921 into the arena 904 and an under-floor air entry 916 to the plenum 906 both of which have restrictors. It is not necessary for each heat exchanger to have both kinds of entries. Some heat exchangers could have only tangential entry 921, some heat exchangers could have only under-floor entry 916, and some heat exchangers could have both tangential entry 921 and under-floor entry 916. The design could permit having the warm air outlet of every second or fourth heat exchangers 901 routed to arena 904 and the air warm air outlet of the remaining cells 901 routed to the under-floor plenum 906 only. There could be sectors without heat exchangers 901. Sectors without heat exchangers could have turbines exhausting either into the arena 904 via tangential entry ducts 921 or into the under floor plenum 906. In FIGS. 15 and 16, there could be turbines, located in the space between heat exchangers 901, exhausting into the under-floor plenum 906. These turbines could exhaust into the under-floor plenum 906 via radial passageways located under tangential entries 921. There could be sectors without heat exchangers or turbines set aside for possible future vortex engine capacity expansion. Sectors without heat exchanger or turbines could be used to provide access for operation, observation or maintenance.
[0159] All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the Figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood. Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “top”, “bottom”, “first”, “second”, “inside”, “outside”, “edge”, “side”, “front”, “back”, “length”, “width”, “inner”, “outer”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention.
[0160] Although the method and apparatus of the present invention has been described in connection with the preferred embodiment, it is not intended to be limited to the specific form set forth herein, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents, as can be reasonably included within the spirit and scope of the invention as defined by the appended claims.
[0161] The Abstract of the Disclosure is provided to comply with 37 C.F.R. section 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate preferred embodiment.
Atmospheric vortex engine
US7086823
[ PDF ]
BACKGROUND OF THE INVENTION
FIELD OF INVENTION
The atmospheric vortex engines has applications in several fields. The invention could produce a large quantity of mechanical energy from solar energy, from naturally occurring heat sources, or from waste heat. The invention depends on differences of elevation and works on the principle that work can be produced when heat is transported upwards by convection. The vortex engine could enhance the power output of thermal power plants by producing mechanical energy in cooling towers and could also improve the efficiency of the conventional part of the power plant by reducing cooling water temperature. The vortex engine is a major improvement on conventional waste heat disposal systems, and its initial use could be to replace conventional cooling towers with superior devices. The improvement in the efficiency of the combined cycle is the result of reducing the temperature of the cold sink from the temperature at the bottom of the atmosphere, typically 30 C, to the average temperature at which the troposphere radiates to space, typically -20 C. In the meteorology field, the atmospheric vortex engine could be used to enhance precipitation, to reduce surface temperature, to reduce instability and severity of storm, to reduce pollution by washing or lifting surface air, or to alleviate global warming by expediting upward heat transport and by reducing fossil fuel consumption.
References Cited
U.S. Patent
4,070,131 1/1978 Yen 415/3
4,275,309 6/1981 Lucier 290/1R
4,391,099 6/1983 Sorensen 60/641.6
International Patent Application
PCTAU99/00037 January 1999 Louat
Other Publications
Byram, G. M. and Martin, R. E, 1962: Fire whirl in the laboratory. Fire Control Notes, U.S. Fire Service.
Michaud, L. M., 1975: Proposal for the use of a controlled tornado-like vortex to capture the mechanical energy produced in the atmosphere from solar energy. Bull. Amer. Meteor. Soc., 56: 530-534.
Michaud, L. M., 1998: Entrainment and detrainment required to explain updraft properties and work disipation. Tellus, 50A, 283-301.
Michaud, L. M., 1999: Vortex process for capturing mechanical energy during upward heat-convection in the atmosphere. Applied Energy, 62/4, 241-251.
Michaud, L. M., 2000: Thermodynamic cycle of the atmospheric upward heat convection process. Meteorol. Atmos. Phys. 72, 29-46.
Michaud, L. M., 2001: Total energy equation method for calculating hurricane intensity. Meteorol. Atos. Phys. 78, Issue 1/2, 35-43.
Mullett, L. B., 1987: The solar chimney overall efficiency, design and performance. International Journal of Ambient Energy, 8(1), 35-40.
SUMMARY OF THE INVENTION
The invention describes an Atmospheric Vortex Engine in which a controlled convective vortex is produced by admitting air tangentially in the base of a cylindrical wall. Naturally occurring convective vortices include dust-devils, tornadoes, water spouts, and hurricanes. The size of a controlled vortex could range from a large dust-devil to a small tornado. The vortex is started by heating the air within the circular wall with fuel. The heat required to sustain the vortex once established can be the naturally occurring heat content of ambient air or can be provided in a peripheral heat exchanger mean located outside the circular wall. The heat source for the peripheral exchanger mean can be waste industrial heat or warm sea water. The preferred heat exchange mean is a crossflow wet cooling tower. The mechanical energy is produced in a plurality of peripheral turbines.
The cylindrical wall could be 50 to 500 m in diameter and 50 to 150 m high. The diameter of the vortex at its radius of maximum tangential velocity at ground level, the eyewall diameter, could be a half to a quarter of the diameter of the circle of deflectors. The vortex could extend to a height of up to 15 km. The power output of a 300 m diameter station could be in the 100. to 500 MW range.
An vortex cooling tower could increase the electrical output of a thermal 500 MW thermal power plant from 500 to 700 MW by converting 20% of its 1000 MW of waste heat to work and increase the power output of a power plant by up to 40%. The power output could be larger when the ambient has instability and smaller when the atmosphere is stable. The chimney effect of the vortex would extend higher than the chimney effect of a natural draft cooling tower even when the atmosphere is stable.Prior Art Without Vortex
U.S. Pat. No. 4,275,309, Lucier 1981, describes a solar energy system consisting of a chimney located in the center of a transparent solar collector. A solar chimney power plant similar to the one described in Lucier's patent, was built in Manzanares Spain in the 1980's. The Manzanares plant had a chimney 200 m high by 10 m in diameter located at the center of a solar collector 200 m in diameter; the turbine was located in the base of the chimney. The plant operated successfully for 7 years and had a power output of 50 kw, see Mullett (1987).
There are two major problems with the solar chimney: the chimney has to be very high to achieve significant heat to work conversion efficiency and a solar collector with a transparent roof has to cover a large area. Sorensen realised the height difficulty and proposed using an inflatable pressurized rising conduit suspended from a buoyant balloon, U.S. Pat. No. 4,391,099.Prior Art with Vortex
Louat's, international patent application PCT/AU99/00037, replaced the physical chimney an unbounded vortical chimney. In the Louat patent application, the air is deflected tangentially as it enters the circular heat collector with the transparent roof, and exits the collector as a vortex via a central opening in which the turbine is located. The Louat system eliminates the need for the physical chimney, but the transparent collector is still required and the power production is limited by the area of the collector. The Louat system has several shortcomings and the embodiment described by Louat may not be practical. There is no means of preventing the vortex from wandering; the fragile transparent roof is located next to the vortex where it could easily be damaged; the turbine in the central opening could adversely affect the formation of the vortex; establishing a strong vortex without artificial heating may not be practical.
Louat's application states: "In a smoke stack, the pressure, at the same height, of the air moving inside is lower than that of still air outside by an amount that increases steadily with the distance from the top of the stack. Thus, the wall of the stack acts as a barrier, that is to say it provides a force which acts to prevent the inward flow of air . . . . Crucial to the operation of the engine is the fact that the barrier to this inward flow need not be material but can be provided through the centrifugal force associated with rotation." Michaud (1975) wrote: "The operation of a natural draft chimney depends on the fact that a chimney is a cylinder in radial compression which prevents convergence in the horizontal plane in spite of the fact that at a given level the pressure is less inside than outside . . . . The centrifugal force produced by the rotation of a mass of air can prevent horizontal convergence just as well as the solid wall of a chimney". The concept of replacing the physical chimney with a vortex was described by Michaud prior to Louat's application. Michaud (1998) showed that, without a tube or a vortex, lateral entrainment rapidly reduces the buoyancy of rising air.
The vortex power station shown in FIG. 1 of Michaud (1975) is closer to the present invention than the Louat application. Louat and Michaud both realized the possibility of replacing the physical chimney with a vortex, but the mechanism described in Louats application was not an improvement on system previously described by Michaud in 1975.
The solar chimney, the unbounded vortical chimney, and the vortex engine have the same thermodynamic basis. This thermodynamic basis is essentially the same as that of tornadoes, dust devils, waterspouts, hurricanes and firewhirls. Upward heat convection is responsible for producing circulation in numerous industrial processes including: boilers, reboilers, natural draft chimneys, and natural draft cooling towers.
Yen, U.S. Pat. No. 4,070,131, proposed a tornado-type power system where the energy of the vortex is derived from the kinetic energy of wind entering tangentially in the side in a tall vertical circular tower. Yen's patent is not relevant because it is not based on thermodynamic conversion of heat to work during upward heat convection.Prior Art by the Inventor
Michaud (1975) realized that the heat content of surface air can be sufficient to produce work when air is raised, and that this upward heat convection process is the source of the energy of tornadoes. Michaud tried to interest atmospheric scientists in the energy production possibility of the tornado process in several peer reviewed articles published mainly in meteorological journals.
Michaud (1975, 1999) proposed using heat from a fire to start the vortex and using either tangential entry deflectors or a rotating screen to give the converging air circulation. Michaud (1998, 1999, 2000, and 2001) developed the thermodynamic basic of the process, pointed out the huge energy production potential of the process, and need for development work.New Elements Not Previously Disclosed
The purpose of this patent specification is to protect specific embodiments not previously disclosed in order to make developing the process financialy attractive. The concept of using a convective vortex to replace a physical chimney was placed in the public domain by the inventor, this patent covers specific embodiments not yet in the public domain.
New mechanism described in this patent and not revealed in the prior disclosures include:
the use of a cylindrical wall significantly higher than the tangential entries of its base,
the use of a heat exchange mean upstream of the tangential deflectors,
the use of waste heat or warm seawater to heat the air and enhance energy production,
the use of tangential entry deflectors preceded by adjustable restrictors,
the use of peripheral turbines,
the use of two levels of deflectors to permit independent control of tangential velocity in the bottom layer and the layer immediately above.
The use of combinations of fixed deflectors to control the circulation of the converging air.
The concept of using a cylindrical wall 5 to 30 times higher than the deflectors located in the base of the wall is a key feature of this patent. The wall acts as a short chimney producing enough differential pressure to get the vortex started. The wall prevents air from entering the vortex without going through the deflectors and prevents the vortex from drifting away as a result of horizontal wind. The wall makes it possible to control of the vortex by adjusting the angle of entry of the air with deflectors and the quantity of air entering the station with adjustable restrictors. The vortex intensity can be reduced by orienting the deflectors in the radial direction and restricting the flow. The area of the tangential entry openings is small relative to the area of the cylinder. Tangential entries a few meters high could be sufficient for a vortex engine with a circular wall 300 m in diameter by 80 m high.
The concept of using a lower layer of air with little rotation and an upper layer air with higher rotation is another important novel feature. The rotation of the upper layer is responsible for producing the centrifugal force which prevents entry of ambient air into the vortex above the cylindrical wall; the relative absence of rotation in the bottom layer eliminates centritugal force in the bottom layer and lets surface air converge into the base of the vortex without being opposed by centrifugal force. As a result of the absence of centrifugal force in the bottom layer, the pressure at the turbine outlet approaches the pressure at the eyewall of the vote The difference in pressure between ambient air and the turbine outlet pressure is used to drive the turbines and to produce the work. Movies of tornadoes occasionally show a layer of dust hugging the ground and rushing into the base of the vortex.
Firewhirls are common in large fires. Large fires have occasionally started tornadoes: San Luis Obispo Calif. tank farm fire, Hamburg bombing and others: Laboratory firewhirls are produced using vertical cylindrical enclosures with a few lone vertical tangential entry slots in their side, Byram and Martin (1962). The inventor built a physical model using a vertical cylinder 50 cm in diameter by 60 cm high with fixed tangential entries 5 cm high at the tube base. An intense vortex was produced by burning a small amount of gasoline spread on the concrete base on which the model was placed. A firewhirl generator with a ring of short tangential entries at the bottom of the cylindrical wall is an improvement over a firewhirl generator with long vertical tangential entries.
The cylindrical wall concept separates the chimney mean from the heat collection mean. The collector could be a solar pond located at a distance from the vortex. The energy produced as a result of increasing the effective height of the chimney would be more than make up for the energy required to pump brine up to the top of the cooling tower.
Replacing the physical tube with a vortex opens the possibility of increasing the height of the chimney effect from 200 m to 15000 m or more. The air rising in the vortex behaves like a spinning top; friction would reduce the rotation of a massive top very slowly. The spinning rising air would lose little of its rotational inertia in the 30 minutes or so required for the air to rise from the surface to its level of neutral buoyancy. In addition, the kinetic energy of the spiraling air is recovered at the top of the vortex as the vortex diverges.
The heat content of the air at the bottom of the atmosphere is often sufficient to sustain a vortex and can be supplemented with waste heat from power plant or with warm sea water. Wet cooling towers are the preferred heat exchange mean; they widely used in power plants because they are ideally suited for transferring waste heat from water to air.Thermodynamic Basisa. Work Production During Upward Heat Convection
The atmosphere is heated from the bottom and cooled from the top because it is transparent to short wave solar radiation and opaque to long wave radiation. Heat is transported upward by convection and mechanical energy is produced during the upward heat convection process because the work produced by the expansion of heated air is greater than the work required to compress the same air after it has been cooled. The upward heat flux at the bottom of the atmosphere averages 100 to 150 W/m<2> . The average temperature at which the heat is received at the bottom of the atmosphere is about 20 C.; the average temperature at which heat is given up by the atmosphere averages about -20 C., the average temperature at which the troposphere radiates to space. The fraction of the heat carried upward which is converted to work is determined by Camot efficiency (nc) which is equal to nc=1-Tc/Th, where Th and Tc are the temperatures of the hot and cold sources respectively, in degrees Kelvin. The average heat to work conversion efficiency for heat carried upward in the atmosphere is approximately 15%. The efficiency is essentially independent of whether the heat is carried upward as sensible or latent heat. In the absence of a mechanism to capture the mechanical energy, the mechanical energy dissipates and reverts to heat.b. Work Production when a Mass of Air is Raised
The work produced when a unit mass of air is raised to its level of neutral buoyancy is known in meteorology as Convection Available Potential Energy (CAPE). In tropical oceanic areas CAPE is usually between 800 and 1800 J/kg. In continental areas CAPE can be as high as 4000 J/kg during periods of insolation; CAPE can be negative during stable periods with low insolation.
CAPE is defined as the work produced when air with the average properties of the bottom 500 m of the atmosphere is raised to its level of neutral buoyancy. The term convective energy (CE) will be used to describe the work produced when any unit mass of air is raised to any level to avoid conflicts with the rigid CAPE definition. The CE of surface air is at a maximum when it is raised up to its level of neutral buoyancy, which is usually near the top of the troposphere. The maximum CE of surface air is usually slightly higher than CAPE because the enthalpy of surface air is usually higher than the average enthalpy of the bottom 500 m of the atmosphere. A CE of 1000 J/kg corresponds to the energy which can be produced when a kilogram of water is lowered 100 m; there is an abundance of air,at the bottom of the atmosphere whose CE is 1000 J/kg or higher.
CE is often negative up to the level of free convection, which is usually 500 to 1500 m high. Beyond the level of free convection, CE increase gradually with height reaching a maximum at the level of neutral buoyancy which usually around 10 to 15 km. Surface air is frequently in a metastable state wherein a small quantity of mechanical energy is required to raise the air to the level of free convection and wherein a much larger quantity of energy is produced as the air rises from the level of free convection to the level of neutral buoyancy. The process is analogous to a syphon; a small quantity of energy must be provided to release a much larger quantity of energy. Transmitting the energy produced in the upper part of the lifting process downward requires a leak tight tube. Adding heat to the air at the bottom of the atmosphere increases its buoyancy and reduces the level of free convection. For air which rises its level of neutral buoyancy, the increase in the CE as a result of heat addition is typically 15 to 30% of the added heat, whether the heat is added as sensitive or latent heat.
CE is equal to the decrease in the enthalpy of air raised isentropically minus the increase in the potential energy of the same air.
CE=-[Delta]h-[Delta]gz
which is a form of the well known total energy equation, where -[Delta]h is the change in the enthalpy of the raised air, and where -[Delta]gz is the change inpotential energy of the raised air. The troposphere is the earth's ultimate heat sink; rejecting waste heat to the upper troposphere has the potential of reducing the cold source temperature of a thermal power plant from 30 C. to -20 C. and of increasing the efficiency of:the power plant.
The cold source temperature depends on the height to which the air is raised. The theoretical efficiency of the solar chimney is, n=0.033 z, where n is the efficiency and z is the height in kilometers, Mullett (1987). The theoretical efficiency of the 200-m Manzanares solar chimney was 0.16%. The work produced in the Manzanares solar chimney was 0.16% .of the heat received. The solar collector increased the air ternperature by 20 C.; the heat received was therefore 20000 J/kg. The work produced was 130 J/kg of which 70 J/kg was extracted by the turbine. The power output of 50 kw is simply the product of the work extracted per unit mass by the flow: 50 kw=60 J/kg*833 kg/s, Michaud (1999). Increasing the height of the chimney by a factor of 50 would increase its efficiency from 0.1% to 5%; increasing the diameter of chimney from 10 to 50 m would increase the flow by 25 fold; the combined effect could increase the power output by a factor of 1250 increasing the power output from 50 kW to 62 MW.
Michaud (1999; 2000, and 2001) explained the thermodynamic cycle of the atmosphere and described methods for calculating the work produced per unit mass of air raised; the theory is directly applicable to the vortex engine. A more complete explanation of the energy conversion process can be found in the cited articles.
DRAWING LIST
FIG. 1 Basic vortex engine consisting of a circular wall with tangential entry slots at its base, plan view.
FIG. 2 Basic vortex engine consisting of a circular wall with tangential entry slots at its base, elevation view.
FIG. 3 Preferred embodiment, vortex engine with peripheral air heater consisting of crossflow cooling tower with turbines in the cooling tower inlet, plan view.
FIG. 4 Preferred embodiment, vortex engine with peripheral air heater consisting of crossflow cooling tower with turbines in the cooling tower inlet, elevation view.
FIG. 5 Vortex engine without the heat exchange mean, plan view.
FIG. 6 Vortex engine without the heat exchange mean, elevation view.
DESCRIPTION OF DRAWINGS
FIGS. 1 and 2 show the basic Atmospheric Vortex Engine consisting of a vertical cylindrical wall 101, with a plurality of tangentially oriented entry slots at its base, the slots are separated by a plurality of adjustable deflector vanes 103. The complete vortex generator is called "the station" while the volume within the cylindrical wall 102 is called "the arena". The direction at which the air enters into the arena is depends on the orientation of the deflector vanes 103. The height of the deflectors is in the order of one twentieth of the height of the circular wall. The convective vortex is started by burning fuel inside the arena in a ring of burners 183. The quantity of air entering the vortex is controlled by adjustable restrictors vanes 107. The restrictors and deflectors are shown oversize in FIG. 1 for clarity, a real vortex station would have a larger number of smaller restrictors and deflectors. The air 131 converging towards the base of the station is deflected tangentially as it passes between the deflector vanes 103, the airs tangential component of velocity increases to conserve angular momentum as the air converges towards the center of rotation; and the air then rises in a vortex 137 near the center of the station.
The functional terms: "restrictors and deflectors" will be used to avoid confusion with the terms: "vanes, louvers and dampers". Restrictors and deflectors can both be made up of vanes. Restrictors, commonly called dampers, have vanes that rotate in alternate direction to restrict flow without affecting its direction. Deflectors vanes can be adjustable or fixed; they can be straight or can have an air foil shape. To produce tangential velocity about the vertical axis, deflector vanes must be vertical and adjustable deflector vanes must be rotatable about the vertical axis. Adjustable vanes can be adjusted manually or remotely. Vanes can be linked together so that one actuating arm can adjust many vanes. The flow direction can be altered by either rotating the whole deflector or just the tip of the deflector. Restrictor vanes should be installed horizontally to prevent the restrictor from affecting tangential velocity. Remotely adjustable deflectors are very costly, therefore fixed deflectors would be used unless deflector adjustment is essential. Manually adjustable deflectors are less costly than remotely adjustable deflectors and would be used where appropriate.
Deflector can act as restrictor because changing their orientation affects the angle of entry of the air in the arena and also changes the size of the slot bet deflectors. Restricting the flow by reducing the size of the slot between deflectors would increase tangential velocity and would not be as effective as using separate restrictors and deflectors.
FIGS. 3 and 4 shows the preferred embodiment of the Atmospheric Vortex Engine complete with peripheral air heater consisting of crossflow cooling tower 61, and with turbines 21 in the air inlets to the cooling tower. The arena 2 is surrounded by a strong impermeable cylindrical wall 1. The cylindrical wall is smooth on the inside and can have a support structure on the outside. The station has a concrete base 48; a concrete cooling tower basin 55, and a concrete floor and can have a hump in the center of the station 85. The circular wall is surrounded by a plurality of crossflow cooling tower bays 61. The two sets of deflectors at the base of the circular wall 3 and 5 serve as the air outlet for the cooling tower and as tangential air entry into the arena. The air supply to the lower set of deflectors 3 comes from the cooling tower 61. The air supply to the upper set of deflector can come from the cooling tower via restrictor 13 or can be unheated ambient air entering via restrictor 15. The height of deflectors 3 and 5 are exaggerated in FIG. 4 for clarity. In an actual station, deflectors 3 and 5 could be 2 to 4 meters high, while the height of the cooling tower bay 61 and of circular wall 1 could be 30 m and 80 m respectively.
The cooling tower 61 serves as the heat sink for the thermal power plant and as heat source for the atmospheric vortex engine. The cooling tower 61 is similar to a conventional crossflow cooling tower complete with cooled water collection basin 55, inlet hot water distributor 53, inlet louvers 63, mist eliminator 65, and inverted "vee" or high efficiency fill 67. The cooled water would be pumped out of the basin via cooled water outlet 57 typically via a submersible pump installed in a sump connected to basin 55. Warm water is returned to the cooling tower water distributor pan 53 via hot water inlet pipe 51. The construction of the cooling tower will be familiar to those familiar with the cooling tower art; each cooling bay 61 is equivalent to half of a conventional crossflow cooling tower. The cooling bays differ from conventional crossflow cooling tower in that the air outlet is via deflectors 3 and 5 instead of via an induced draft fan located at the top of the cooling tower and in that the air inlet is via turbine 21. Entry of air into the cooling tower other than via turbine 21 is prevented by an air tight enclosure 23 which is not needed in conventional cooling towers. The cooling tower has to be air tight and strong enough to withstand the compressive force because the pressure in the cooling tower could be 5 to 15 kPa below ambient pressure. The pressure reduction at the base of the vortex is transferred to the cooling tower, the differential pressure at the cooling tower inlet drives the turbines to produce mechanical energy. The lateral walls between cooling bays extend down in the cooling water basin 55 to form a seal 49 and prevent air exchange between bays.
Turbine 21 can consist of a rotating blades with or without adjustable inlet nozzles. During operation, the turbines are the main restriction to the air flow. In turbines with inlet nozzles, the flow through the turbine can be increased by increasing either the number or the size of the inlet nozzles In turbines without inlet nozzles the electrical load on the turbine could be manipulated to control air flow. People skilled in the turbine art would determine the most appropriate turbine type and arrangement. In a turbine with inlet nozzles, the differential pressure across the nozzle accelerates the air giving it kinetic energy; the rotating turbine blades located immediately downstream of the nozzles capture the kinetic energy of the air coming out of the nozzles. The turbine inlet nozzles thus act as both a restriction in the air inlet to the turbine and as a restriction in the air flow to the cooling tower and permit restricting the flow so that the cooling tower can be operated at sub-atmospheric pressure. Adjustable turbine bypass restrictor 25, located in parallel with turbine 61, permits operating the cooling tower without using the turbine or can be used to supplement the air flow in the cooling tower during startup when the draft is too small to get sufficient flow via the turbines.
The velocity of the air in the cooling tower must be kept under approximately 3 m/s to prevent damaging the fill. The cross-sectional areas of turbines 21 or outlet deflectors 3 and 5 are much smaller than the cross-sectional area of the fill 67 to keep the velocity in the fill low. The purpose of diffusers 23 is to reduce the velocity at the turbine outlet and to distribute the air evenly to the fill. The diffuser 23 located downstream of the cooling tower inlet could consist of solid panels or of perforated screens. The velocity of the air at the outlet of the turbine inlet nozzle could be 40 to 80 m/s. The velocity of the air entering arena 2 at the outlet of lower deflector 3 could be 10 to 30 m/s.
The cooling bays 61 are separated by radial passageways 41 which can be used to admit unheated ambient inside the circular wall via deflectors 143, 145 and restrictors 144 146. Restrictors 144 and 146 could be replaced with turbines and used to produce energy in addition to the energy produced by the turbines located in the cooling tower inlets. Some of passageways 41 may be used simply for gaining access to the center of the station; access passageways would require air locks consisting of double air tight doors. The inter-bay passageways may not be essential and could be eliminated or reduced in number. The cooling tower could consist of one circular structure if inter-bay passageways 41 are not provided. The air supply to the upper deflectors 5could come from the inter-bay passageway via a circumferential duct with an appropriate inlet restrictor instead of via restrictor 15 located above deflector 5. The inlet to the upper deflectors 5 is shown at the top of the cooling tower in FIG. 4 to illustrate the fact that the upper deflector air does not have to go through the cooling tower. Supplying the air to the upper deflectors from the radial passageways would be more practical in an real station since the heights of deflectors 3 and 5 are exagerated in FIG. 4 for clarity.
The vortex would be started by temporarily heating the air inside the circle of deflector with heater 83. There are many possible heater arrangements and heat sources. The heated air used to start the vortex should not be too warm because entrainment of ambient air into the free vortex above the cylindrical wall increases with horizontal temperature differential. The preferred startup burner arrangement would be a ring of many small propane burners designed to aspirate lots of air and to produce a warm gas of low temperature. The burners could be oriented close to tangentially to assist vortex formation. Alternatively the hot gas for starting the vortex could be produced in burners located outside the station and brought to the starting heat ring via an underground duct; in which case the starting gas could be furnace flue gas or gas turbine exhaust. Using the startup heater for 10 to 30 minutes should be sufficient to establish the vortex.
The station has two levels of converging air corresponding to lower deflectors 3 and upper deflector 5. The two layers are separated by an annular roof 11 which could be supported on thin columns. The two layers arrangement permit giving the air in the bottom layer less tangential velocity than the air in the layer above. The purpose of giving the lower layer less tangential velocity that than the upper layer is to reduce centrifugal force is to prevent centrifugal force from opposing convergence in the lower layer so that the pressure at lower deflector outlet approaches the pressure at the base of the vortex. The purpose of supplying ambient air to the upper deflector 5 via restrictor 15 is to provide a source of air at higher pressure than the air in the cooling tower to ensure that there is sufficient flow through the upper deflector. The purpose of restrictor 13 is to permit the use of warmed cooling tower air when the pressure in the cooling tower is sufficient to produce the required flow in upper deflector 5. One of the two restrictors 13 and 15 supplying air to upper deflector 5 must be fully kept fully closed to prevent ambient air from entering the cooling tower via the air supply to deflectors 5.
The hump in the center of the station 85 helps turn the converging flow upward. Removing the circulation in the bottom layer makes it possible for the air to converge right up to the center of the vortex. The two layers system increases the effective area of the updraft tube and the quantity of energy which can be produced for a given diameter vortex; upward flow can occur right up to the axis of the vortex and not just in the eyewall annulus thereby increasing the area of the updraft. Radial friction flaps 81 could be used on the floor of the station or on the upper surface of annular roof 11 to further reduce tangential velocity next to these surfaces and enhance convergence. Adjustable radial friction flaps could eliminate the need for two levels of deflectors by reducing the tangential velocity of the air near the floor of the station.
Having a sub-atmospheric pressure in the cooling tower increases the heat transfer between the air and the water because for the same temperature air can hold more water vapor at lower pressure, Michaud (2001). The ratio of the mass flow of air to the mass flow of water in a cooling tower is typically 1:1. A vortex cooling tower should permit increasing the air flow without increasing the cost of the energy required to circulate air. The combination of higher air flow and lower pressure should reduce the cooled water temperature and result in an improvement in efficiency of the conventional part of a thermal power plant beyond the energy produced in cooling tower peripheral turbines 61. The spraying of the air with warm water is the source of the energy in hurricanes, in waterspouts, and in the wet cooling tower vortex engine. Michaud (2001) showed that the maximum pressure reduction in hurricanes can be explained by the air approaching equilibrium with the warm sea surface temperature at the reduced eyewall pressure. Bringing air in equilibrium with 30 C. sea water at reduced pressure is sufficient to produce a central pressure reduction of 15 kPa.
Ambient air 31 enters the cooling tower via turbine 61 and heated air 33 leaves the cooling via lower deflector 3. A parallel stream of air 32 and 34 enters the arena via restrictor 15 and upper deflector 5 without being heated. The two streams are seperated by annular roof 11 as they enter the arena. The combined streams turn upward as they approach the center of the station and spiral upwards as they rise 35 forming the vortex 37. The lower 3 and upper 5 deflectors are adjusted so that the lower layer has less circulation than the upper layer.
The vortex engine would be provided with a state of the art control system from which the position of restrictors and remotely adjustable deflectors and other control valves could be manipulated. The system would have sophisticated instrumentation to measure: pressure, differential pressure, temperature, humidity, air flow direction and velocity. There could be observation post at the inner end of a some of the interbay passageways and a radial observation tunnel under the floor of the station.
The CAPE of surface air is often sufficient to produce a vortex without heat addition. Under such conditions, increasing the heat content of the rising air may not be desirable and could make the vortex more difficult to control. FIGS. 5 and 6 show a vortex generator without the continuous heat mean and illustrates other alternative features. Cylindrical wall 201 curves inward like a short hyperbolic cooling tower, using an inward curving wall has the advantages of reducing entrainment of air from above the wall into the base of the vortex and could be less costly for large stations.
Lower air 233 enters the station via turbine 221, which drives generator 222, and goes through a diffusing screen 227 before being ducted to lower deflector 203. Upper air enters via restrictor 215 goes through diffuser 229 and enters the arena via upper deflector 205. The vortex 237 is started by burning fuel in fuel ring 283. Radial friction flaps 287 near the central hump 285 reduce the tangential velocity and encourage convergence in the center of the vortex.Alternative Embodiments
The vortex can have clockwise or counter-clockwise rotation; a vortex engine could be designed to produce a vortex with clockwise or counter-clockwise rotation or both. The primary direction of rotation for which the station is designed will be called the positive direction. Adjustable deflectors would facilitate control, but a large number of adjustable deflectors would be very expensive. Combinations of fixed deflectors could be used as an alternative to adjustable deflectors. In FIG. 4, deflectors 3 and 5 could have fixed positive direction while deflectors 43 and 45 could have fixed negative orientation, the net circulation of the air flowing in the arena could be reduced by restricting the flow to deflectors with positive orientation and opening the flow to deflectors with negative orientation. It is not necessary the that the air flow through all the cooling bays be the same or that all cooling bays be in use. Fixed deflectors 3 and 5 could be oriented close to tangentially on a few the bays used for startup and more radially on the other bays.
The velocity at the outlet of a restriction or deflector is proportional to the square of the differential pressure across the restriction or deflector. A differential pressure of 5.7 kPa across a restrictor produces outlet velocity of 100 m/s; a differential pressure of 0.06 kPa produces an outlet velocity of 10 m/s. The open area of the restrictors can be smaller than area of the restrictor because the differential pressure across the restrictor is larger. Using combinations of fixed deflectors could reduce the number and area of the adjustable surfaces by 50 to 80%.
In dry climates, dry cooling tower could be more appropriate than wet cooling towers; dry cooling tower would have the advantage of eliminating water consumption. The heat transfer mechanism in dry cooling towers is similar to that in dust-devil where the converging air comes in intimate contact with the hot soil and with hot sand spray. In arid climates, wet natural draft cooling tower do not work as well as forced draft cooling towers because the evaporative cooling is so high that it tends to reduce the temperature of the air. For the same reason, vortex engines with dry cooling tower might be preferable in dry climates.
While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the claims.
DESCRIPTION OF OPERATION
Start Up Procedure for the Preferred Embodiment with Remotely Adjustable Deflectors
1. Position lower inlet deflectors 3 to give the converging air maximum tangential deflection.
2. Position upper inlet deflectors 5 to give the converging air maximum tangential deflection. Close both air inlets restrictors 13 and 15 to upper deflector 5.
3. Ensure that radial air passages 44, 46 are close.
4. Open the turbine 61 inlet nozzles and the turbine bypass damper 25.
5. Fill cooling tower basin 55, start the water circulation, start warming the circulating water with waste process heat.
6. Gradually increase central startup heat source 83.
7. Monitor central pressure and air velocity, control the vortex intensity by reducing firing, by decreasing the deflection 3, and by restricting the flow at the cooling tower inlet 21, 25.
8. Gradually open ambient air inlet to upper deflector 5 via louver 15.
9. Gradually move lower inlet deflectors 3 towards the radial direction to reduce the pressure in the cooling tower.
10. Close the turbine bypass restrictor 25 and turbine 61 inlet nozzles as necessary to keep the velocity in the cooling bay from getting too high.
11. Reduce the deflection at lower deflectors 3 and upper deflectors 5 and restrict the flow to upper and lower deflector.
12. The convective vortex could tend to rapidly increase in intensity because a large vortex will keep rising until the rising air reaches its level of neutral buoyancy. The base pressure reduction is proportional to the height of the vortex. At an upward velocity of 10 m/s a vortex could reach a height of 10 km in 20 minutes.
13. Gradually increase the temperature and flow of the warm cooling water entering the cooling tower.
Stopping Procedure.
1. Gradually restrict the flow to the turbine at the turbine inlet nozzles, restrict the flow of air to the upper deflector with louvers 15, orient upper and lower deflectors 3 and 5 as necessary to reduce the tangential velocity of the converging air to zero, use negative orientation on some deflectors if necessary.
2. For a station with fixed deflectors restrict the flow to positive orientation deflectors 3 and 5 and open the open the flow to negative orientation deflectors 43 and 45.
3. Reduce or stop the cooling water circulation.
4. In an emergency, douse the vortex with cold water from remote operated fire hydrants located at the inner end of radial passageways.
US4070131 -- Tornado-type wind turbine
Inventor(s): YEN JAMES T
Applicant(s): GRUMMAN AEROSPACE CORP
[ PDF ]
Atmospheric wind is admitted tangentially into a vertically extending structure and directed against the interior curved surface of the structure to produce vortex flow. The structure is open ended and spaced from ground or connected to a ram-air subterranean tunnel. The vortex flow and corresponding low pressure core draws ambient and/or ram air into the bottom of the structure to drive a horizontal turbine.
BACKGROUND OF THE INVENTION
The use of the wind to provide power for various uses including pumping and grinding dates back to the fifteenth century in Europe. In general, windmills provided mechanical work only on a limited scale for very local use.
With the ever increasing demands on energy sources, all possible sources are being researched. This is particularly true if the new source is (i) nonpolluting and inexhaustible, (ii) capable of supplying energy on a national scale, for example, exceeding 100,000 MW in capacity (the present U.S. electrical generating capacity is around 400,000 MW), (iii) relatively simple in technology so that it can be developed in a decade, and (iv) economically feasible so that the new power plant can compete with the existing or forthcoming fossil or nuclear power plants.
Wind energy has enough potential to qualify as such a new energy source. However, its energy density is low (its kinetic energy is equivalent to 15 watts per square foot cross-section at 15 mph) and it is highly fluctuating in speed and in direction, particularly near the ground.
The challenge is then to build wind energy systems of large unit size. Each unit can collect large amounts of wind to generate many megawatts of energy, can extend to great heights (e.g. several thousand feet above the ground) where wind is more steady and abundant, and can withstand the extreme winds of hurricanes and tornadoes.
For various reasons discussed below, the standard type windmill, i.e., a propeller assembly positioned to face the wind, has failed to meet this challenge. When adapted to drive an electrical generator, a standard windmill of more than 25 feet in diameter is needed to generate sufficient power for a single home. A long-range program is being pursued by the U.S. government to build a 125 feet diameter unit for generating 100 kilowatts. And the largest unit ever built generated only 1 megawatts with blades of 200 feet in diameter.
As to the standard windmill design it has significant drawbacks which make them undesirable for small energy production and unacceptable for large energy production.
These drawbacks fall into basically three categories: fluid dynamics, stress and electrical. The fluid dynamics difficulties may be best appreciated from a consideration of the Betz momentum theory. The column of air (wind) impinging on the windmill blades is slowed down, and its boundary is an expanding envelope. Disregarding rotational and drag losses, a theoretical maximum power output, due to the slowing of the wind and corresponding expansion of the boundary envelope, is approximately 60% of the power contained in the wind. Additionally, the structure used to support the blades of the windmill and the less than ideal performance of the blades themselves present interference losses further decreasing the power output.
Mechanical stresses induced on the blading and supporting structure present a further limitation, especially for large windmills. On the supporting structure, the axial stress, representing the force tending to overturn the stationary windmill, or the thrust on the bearing must be kept within limits at all wind speeds. To accomplish these results and to generate sufficient power, large diameter blades with built-in mechanisms for adjusting the pitch angles of the blades have to be utilized. The mechanisms make the blades fragile and costly.
Large diameter blades over 100 feet in diameter present significant dynamic stress problems when used in standard windmills. The combination of gravitation force and torque force on each blade element functions to cyclically stress the element as it rotates in a rising direction and then falling direction. Moreover, with vertically rotating blades, changes in median wind velocity and the specific wind velocity at different elevation along the path of the blade greatly influence the cyclical stresses and power output of the wind turbine.
Long blades supported at their roots and under the influence of the aforementioned oscillating forces are subjected to an increasingly severe and complex system of dynamic instabilities. It becomes increasingly difficult (and expensive) to safeguard against instabilities. Blade stiffness to weight ratio improvements and advanced design methods can help, but there will always be a practical maximum to the size of a conventional wind turbine.
Finally, wind turbines of the windmill type are not well suited for use in major power installations, particularly in power grids. In order to provide stability of the network, energy generators coupled to power grids must be maintained within critical voltage and frequency ranges and must be capable of furnishing the required amount of power whenever called upon by the grid dispatcher. The standard windmill is particularly sensitive to changes in median wind speed resulting in highly variable voltage, frequency or power output produced by the generators driven thereby. Moreover, large power output required for economic operation are not feasible due to stress problems; and difficulties arise in coupling the blade shaft, which rotates in the range of 20-100 rpm, with electric generators used in power grids which operate in the range of 600-3600 rpm.
SUMMARY OF THE INVENTION
The present invention overcomes many of the drawbacks of the standard windmill type wind turbine by utilizing a structure that operates on the principle of a tornado type vortex flow regime. This type of device is unlimited in size and can withstand the extreme winds of hurricanes or tornadoes.
The present invention (particularly, the preferred embodiment of the present invention) includes a stationary structure in which ordinary wind flow is transformed into a vortex. The structure is open at the top and bottom, and sides are comprised of a system of vertical vanes. The vanes in the direction of the wind are opened to admit the wind and direct it in a generally circular path around the interior of the structure. The circularity of flow and acceleration produces a laminar or turbulent flow vortex having a low pressure core.
The structure is raised from ground elevation so that the low pressure core draws ambient air into the bottom and through the structure. The vortex flow exits through the top of the structure for degradation in the atmosphere. The inertia of the rotating vortex partially overcomes and compensates for fluctuations in wind speed to enable a turbine, which is located within the structure, to be driven more uniformly. The turbine is positioned for rotation in a horizontal plane and is driven by the ambient air drawn into the bottom of the structure by the vortex. The vortex is driven along substantially the entire height of the structure and deceleration occurs downstream of the structure.
Cables are used to hold down the stationary structure to the ground. As a consequence, both the structure and the turbine may be built in large sizes sufficient for generating many megawatts of electricity, yet strong enough to withstand extreme winds of hurricanes or tornadoes.
An alternate embodiment, showing a different variation in tower shape and air inlet, is also specifically described in the present invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic top plan view of a wind turbine device in accordance with the present invention in which the structure is generally hyperbolic in shape;
FIG. 2 is a side elevation view of the wind turbine of FIG. 1;
FIG. 3 shows a spiral as a possible shape of the tower structure; and
FIG. 4 shows a subterranean tunnel and a ram-air inlet for admitting ram-air to the turbine located at the bottom of the tower structure.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will hereinafter be described in detail a preferred embodiment of the invention, and alternatives thereto with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.
INTRODUCTION
Before proceeding with a description of the preferred embodiment, a short introduction to vortex flow will be presented to provide a clear understanding of the operation of this invention.
There are basically three different types of rotating flow regimes commonly referred to as a vortex. The first flow regime is rigid body rotation in which the fluid rotates as a solid body and the tangential velocity increases with radial distance from the center of rotation, as observed in flows where the viscous effect is dominant.
The second flow regime, laminar potential vortex includes the condition of negligible viscous effect. In this regime the tangential velocity will increase as radial distance decreases toward the center of rotation. When the circulation (.GAMMA. = V0 R) or Reynolds number (Re = .GAMMA./.nu.) is not large (Re < 10@5 to 10@6) then laminar potential vortex flow exists.
The third flow regime is the turbulent potential vortex and is characterized by Reynolds number greater than 10@6. In this vortex flow random eddies appear within the vortex to create turbulence.
Both laminar and turbulent vortices are characterized by a small concentrated core in which the pressure is low and axial flow is concentrated. The degree of lowering in the core pressure is related to the Reynolds number and differs with the type of vortex. Turbulent vortices produce the greatest reduction in core pressure. The greater reduction of core pressure is not due to the turbulence, but rather the high Reynolds number which allows the potential vortex structure to prevail closer into the center where velocity increases sharply and which also inevitably results in turbulence at the core. The natural tornado has a Reynolds number exceeding 10@7 or 10@8 and is therefore highly turbulent.
The tower structure of the invention, as will be described in greater detail below, preferably has a diameter of several hundred feet and the vortex flow produced therein will have a Reynolds number preferably greater than 10@7 at ordinary wind speed, however laminar potential vortex flow may also be utilized.
THE TOWER STRUCTURE
FIGS. 1 and 2, show a wind turbine 10 in accordance with the present invention. The apparatus includes a vertical tower structure 12 of generally hyperbolic configuration although other shapes, including cylindrical, may also be used.
Tower 12 is a stationary structure with movable vanes. With the aid of a system of cables 50, the tower is able to withstand extreme winds of hurricanes or tornadoes. Cables 50, are attached to the tower at various locations 52, and link the tower to foundations, 54 in the ground G. Sufficient number of cables are spread from the tower in various directions, so that they can absorb large stresses due to extreme winds from any direction. Tower 12 is formed by a bottom intake portion 14 which is generally bell shaped and supported at an elevated position from the ground G by struts 15. The shape of portion 14 is designed to act as a funnel to permit ambient air to be drawn into the structure from a large surrounding area and accelerated as it passes through the structure.
The intake portion 14 defines a throat 16 at its upper portion which has the minimum cross section of the tower. Extending upwardly from the intake portion is a wind inlet portion comprised of a plurality of vertical vanes 18 which circumvent and form the periphery of the tower. Each vane 18 is rotatably mounted at each end so that the vane may be operated in much the same manner as a venetian blind. The bottom end of each vane is mounted on the top of the intake portion 14 and the top end is attached to an exhaust portion 20 at the top of the tower.
By selectively opening the vanes in the direction of the wind, a vortex flow regime is introduced in the tower. To this end, each vane is independently operated by a control mechanism 22 (only one being illustrated) to open and close the vane. A wind direction sensor 24 is coupled to each control mechanism 22. Those vanes facing the wind W are opened and are preferably opened to an orientation where the vanes are tangent to the circular periphery of the tower and a 180 DEG portion of the vanes are opened. The remaining vanes are closed and define a curved flow boundary or convolute chamber which cooperates with the tangential opened vanes to induce the incoming wind to go to a vortex flow regime.
The incoming wind W thus creates a vortex having a low pressure core which produces an upward flow to draw air from beneath and around the bottom of the tower. Preferably, a tower of the invention is at least two hundred feet in diameter at the throat and has a height in the range of 2-4 times the throat diameter.
The upward flow of air produced by the vortex is utilized to drive turbine blades 30 which are mounted to a vertical shaft 32 for rotation in a horizontal plane. Shaft 32 is supported in a ground bearing 34 and carries a combination flywheel pulley 36. Flywheel-pulley 36 stores rotational energy and drives an electrical generator 40 by means of drive belt 42.
THE TOWER FLOW REGIME
While not wishing to be restricted to any particular theory of operation, it is believed that the gross flow regime produced by this invention can best be explained by the following considerations. The wind turbine of this invention operates on a totally different principle as compared to the standard windmill type discussed above. Rather than using only kinetic energy, wind turbine 10 utilizes also the potential or pressure energy of the wind. For a wind of 15 m.p.h., the ratio of the kinetic energy to the pressure energy is about 0.03%. Thus, the potential reservoir of energy of this type is very significant.
The induced vertical air velocity in the tower will be several times the velocity of the incoming wind. Since the power output of the turbine will be proportional to the product of the volume flow rate (which depends linearly on the axial velocity) and the pressure drop available across the turbine, the power output achievable by the wind turbine will be significantly greater than that of the ordinary wind turbine.
The wind turbine 10 has significant advantages over standard windmills. The vortex created within the tower is driven by the incoming wind along substantially the entire height of the tower. Thus, there is no decay of the vortex within the tower and substantial inertia is developed to provide stability. Moreover, wind velocity generally increases with increased height above ground. Thus, the vortex strength may increase and core pressure decrease with height above the turbine blades, thus creating a favorable pressure gradient for the vortex core.
After exiting from the top of the tower, the vortex faces a rising or adverse pressure gradient because the pressure must return to atmospheric level. The vortex core may begin to break down after exit from the tower but incoming wind W passing over the top of the tower along a curved streamline S will impart energy through mixing to the exited vortex. The curved streamline of the top wind allows the vortex core to remain at a pressure lower than atmosphere for gradual breakup at a distance from the tower. Additionally, a suction or low pressure zone is created on the side of the tower where the vanes are closed. This zone further facilitates exhaust and degradation of the vortex as it exits from the tower.
Since the blades 30 of the turbine rotate in the horizontal plane near the ground and are driven by a high speed wind, e.g., 2-6 times wind speed, several major advantages can be achieved. Ultra-high speed flywheels may be used to store the energy of the turbine. Because the induced flow velocity is high, the blades may be rotated at a higher speed than standard windmills for coupling with electric generators operating at 1800 r.p.m. and higher.
With the turbine rotating horizontally, it is under a constant and uniform gravitational force, and it does not interact strongly with its supporting structure. Moreover, the fluctuations and the nonuniformities of the incoming wind may be greatly smoothened by the adjustments of the vertical vanes, and the inertia of the vortex, the flywheels, and the blades. Hence, in contrast to the standard windmill, the size of the tower structure or of the turbine of this invention is not restricted by dynamic stress loadings or instabilities. They are unlimited in size. They can be made large enough (e.g., 400 feet or more in tower diameter and 800 to 1200 feet or more in height) to capture large quantities of wind, generate in a single unit many megawatts of electricity, and be highly competitive in cost against fossil or nuclear power plants.
ALTERNATIVE EMBODIMENT
An alternative tower structure 60 is shown in FIG. 3 in which the tower walls 61 define a spiral cross-section in the horizontal plane. In this manner 61 provides a vertical inlet 62 for admitting wind W into the convoluted chamber 63 to induce a vortex flow regime.
Tower 60 is carried on a system of trolleys 70 at its lower end which ride in a circular track 72 corresponding to the central portion of the tower spiral. Trolleys 70 are powered by suitable means, such as electric motors or engines, and are controlled by a wind direction sensor 75. In this manner, the tower is rotated by the trolleys to position inlet 62 in an orientation tangent to wind W. It will be appreciated that in those circumstances where wind direction is generally constant, the tower may be positioned directly on the ground without provision for turning.
A subterranean tunnel 80 leading from the center of the tower to a location remote therefrom is utilized to admit driven air to the turbomachinery 82. When tunnel 80 is utilized, it is preferable to use a ram-air inlet 84 at the entrance of the tunnel. Inlet 84 has the advantage of slightly increasing the pressure head or stagnation pressure of the air by the ram effect.
Turbomachinery 82 is similar to that described above and include a set of blades 86 which are driven by the air drawn through tunnel 80 by the vortex. The blades in turn drive shaft 88, which is mounted by bearings 89 and carries a high speed flywheel 90. The power output of turbomachinery 82 is thus utilized to drive an electrical generator or other energy conversion system (not shown).