US20200386970A1

US20200386970A1 - Aerostatically Stabilized Atmospheric Reflector To Reduce Solar Irradiance

Info

Publication number: US20200386970A1
Application number: US16/855,817
Authority: US
Inventors: Narayanan Menon Komerath
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-09-24
Filing date: 2020-04-22
Publication date: 2020-12-10
Also published as: US20200249427A1; US10775586B2; US10890735B2; US20200096731A1

Abstract

A method is described to stabilize a reflector in the upper atmosphere to reflect solar irradiance back into Space before it can be absorbed or scattered by Earth's atmosphere. Thin reflective sheets are flown under control in the upper atmosphere above Earth, in contrast to reflecting from Space orbits or the ground. The high altitude enables nearly total reflection. This embodiment uses buoyant aerostatic lift and pneumatic pressure to support and hold sheets stretched while providing aerostatic lift. During the daytime solar power is used to provide energy for propulsion and gain altitude by volume expansion. During the night the aerostatic lift holds the system above controlled airspace. Edgewise gliding permits seasonal movement of the system and station-keeping. In one example application, a swarm of aerostatically stabilized reflectors placed around the edge of the Antarctic continent will reduce summer melting of ice, in order to reverse the rise in sea level.

Description

REFERENCE TO PRIOR APPLICATION

This specification discloses and claims subject matter disclosed in prior application Ser. No. 16/140,161, filed on Sep. 24, 2018 [2018 Sep. 24]. The subject matter is directed to an invention that is independent and distinct from that claimed in the prior application, and names the inventor named in the prior application.

FIELD OF THE INVENTION

The primary field of application is to reduce Global Warming. This method is related to lighter-than-air vehicles.

BACKGROUND OF THE INVENTION

Anthropogenic climate change threatens humanity. Heat and heat-absorbing Green House Gases (GHG) released into the atmosphere are raising Earth's surface temperature. Reference [1] reports that Earth's atmosphere is retaining heat at a net rate of 2.29 Watts per square meter of the Earth's surface. Normalized to the disc area of Earth seen by the Sun, this gives 9.16 Watts per square meter. This is compared to the nominal value of 1350 Watts per square meter of solar energy falling on Earth's atmosphere. The prescribed remedies are controversial because they hinder economic growth or prevent the advancement of subsistence economies. Implementation if any will take a long time. Residents of islands and low-lying coastal areas are threatened by rising sea levels because of the polar ice caps melting. Extreme weather events are already attributed to climate change.
One way to control Global Warming is to reflect a part of the sunlight back into Space. Such a remedy has been proposed by several methods in prior art. These include reflectors or bubbles in Space [2-3], reflective particles or balloons released along with industrial exhaust and other aerosols [4-8], extracting carbon dioxide (CO2) from the atmosphere and ejecting purified air [9,10] and wind turbines pumping Antarctic sea-water to the ice-cap [11,12]. Ground-based tiltable reflectors have been proposed [13]. US national laboratory researchers [14,15] have proposed increasing the albedo of urban areas by mandating white paint on roofs and sidewalks. The above shows that the Prior Art consists of difficult methods that have proved to be impractical, harmful and ineffective. Their long-term effects are not understood. They are not easy to remove once deployed. The above survey also illustrates the extreme measures that have been proposed, implying huge expense and strong and varied concerns. None has to-date been adopted on a large scale.
Prior application No. [Ser. No. 16/140,161] proposed and advanced a solution called the Glitter Belt. The solution is to float reflective sheets in the upper atmosphere. The deployment may be nominally at altitudes near 30,480 m (100,000 ft), using means that ensure that they will not sink below 18,288 m (60,000 ft, the edge of controlled airspace) in the night time. The reflectors are anticipated to be made of thin sheets with low areal density. They will have highly reflective upper surfaces, and the option of flat black lower surfaces. The former is to reflect sunlight in the daytime. The latter is to absorb radiation from Earth at night, so that most of it will then be transmitted by conduction to the upper surface and radiated out into Space. The concept is shown in FIG. 1 (repeated from Prior application [Ser. No. 16/140,161]), the reflectors being highly exaggerated to make them visible to the reader. High-altitude reflectors are far more effective compared to ones on the ground, while being several orders of magnitude less expensive than Space-based reflectors. Simple consideration of optics shows that diffraction will prevent the reflectors from being seen from the ground with the unaided eye.
FIG. 2 is reproduced from Prior application [Ser. No. 16/140,161] and represents one general implementation of the Glitter Belt, where a thin reflective sheet is supported in a stretched attitude to be generally horizontal when in steady level flight. An architecture that is ultimately deployed, may use some combination of this with some other implementation.

SUMMARY OF THE INVENTION

The subject of the present invention is an implementation of the aforementioned Glitter Belt where the reflective sheet is supported in the atmosphere by means of aerostatic lift. One example of this implementation is shown in FIG. 3. This is referred to as the “Balloon Beanie”. This is a subset of the class of aerial vehicles described as “lighter than air”. This designation means that at ground level the overall density of the vehicle, defined as total mass divided by total volume occupied, is lower than that of air at ground level. It uses buoyancy or aerostatic lift to rise to an altitude where it remains at equilibrium with the air at that altitude. In the implementation shown, hydrogen-filled balloons support the reflector sheet, with solar-powered rotors at the periphery providing control, transportation and station-keeping in wind when needed. An inflatable rim filled with hydrogen provides tension to keep the sheet stretched in tension.
It is obvious that helium could be used instead of hydrogen. Helium is generally denser and more expensive compared to hydrogen. Hydrogen is adequate when no humans are carried on the vehicle. Further implementations, for example, ones that combine this implementation with that claimed in the Prior application [Ser. No. 16/140,161] are also anticipated.
While prior work as shown, has anticipated the use of hydrogen and helium balloons, it did not show the way to alleviate a disadvantage of hydrogen. Hydrogen diffuses through the balloon shell. The present invention includes means of alleviating this problem. The means are to incorporate a double-layered thin sheet shell for each balloon and the rim. As claimed in Prior application [Ser. No. 16/140,161], a vacuum pump driven by solar power pulls hydrogen from the space between the two shells and pumps it back into the inner space. In this way the loss of hydrogen by leakage is reduced to negligible level where it no longer becomes the limiting factor on the longevity of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is incorporated from Prior application [Ser. No. 16/140,161]. The sketch in FIG. 1 exaggerates the sizes of individual reflectors to illustrate the Glitter Belt concept. Reflectors in the preferred embodiment of the invention may be concentrated in selected bands or clusters rather than being uniformly spread over the globe. In one implementation the bands are positioned and moved to follow daily northward or southward drift of the summer Sun's daytime trajectory with respect to the local sky, and cross the Earth's Equator twice a year. However this is not essential.

FIG. 2 is incorporated from Prior application [Ser. No. 16/140,161]. It illustrates the Flying Leaf concept, an aerodynamically supported reflector. The Earth's horizon is shown as a thick curved line.

FIG. 3 illustrates one implementation of the Balloon Beanie concept. The reflective sheet is aerostatically supported by lighter than air balloons, typically hydrogen-filled balloons. In this implementation an inflated tube around the periphery provides tension to the sheet and supports solar-powered rotors. These rotors serve one or more of several possible purposes. One such purpose is to provide attitude control. Another purpose is to enable station keeping. A third purpose is to drift with the seasons. A fourth purpose is to change the attitude of the sheet. Framework if any is required, and solar panels, are not shown in FIG. 3. The double-layered structure of the shell with vacuum pump is not detailed in the drawings. In one implementation the solar panels will be attached to the framework at suitable locations.

LIST OF REFERENCE TERMS, NUMERALS AND SYMBOLS


	1	Sun
	2	Hydrogen balloon package used to support Balloon Beanie
	3	Reflective sheet of Balloon Beanie
	4	Inflated peripheral structure of Balloon Beanie
	5	Rotor used to control Balloon Beanie
	6	Central support balloon with telemetry and flight controls

Description of the Aerostatically Supported High-Altitude Reflector

In the present invention, the method to implement one aspect of the Glitter Belt system is to support a reflective sheet using a set of hydrogen balloons. This is shown in FIG. 3. A light, rigid structure will be required. The reflector sheet in the present implementation is circular in shape as shown in FIG. 3. In this implementation, said reflector sheet is stretched over an inflated ring or series of concentric inflated rings with radial supports.
The aerostatically supported reflector concept avoids the need to provide continuous aerodynamic lift, and therefore minimizes the night-time glide requirement. As the sun sets the balloons will cool, so that the gas inside them will increase in density. As a result, balloon volume will decrease, so that the vehicle will come down to lower altitude.
Such altitude loss motion need not be entirely a vertical motion. The altitude loss can be minimized by tilting the sheet so that it glides edgewise through the night, generating aerodynamic lift using the sheet as a large lifting surface. This is anticipated by the fixed-wing aerodynamic implementation in the prior application Ser. No. 16/140,161.
The gliding motion described above can be used to change the position of the vehicle as needed to optimize position with respect to the sun for the next day.
The balloons can be used to hold the sheet in an attitude that is tilted to large angles. Such tilting can be used to maximize reflection of sunlight even where the sun is quite low on the horizon. An example of this is the case in summer over the Antarctic Circle.

The Polar Necklace

Some concepts are anticipated to improve the effectiveness of the first deployed systems. The most urgent visible symptom of Climate Change is the breakup of the Antarctic Ice Shelves [16]. These are large sheets of ice formed by the flow from glaciers coming off the higher elevations of Antarctica. Large portions of these ice sheets are floating on the ocean. As ocean temperature increases the balance shifts between summer-time melting and winter ice accumulation. As a result the sheets become thinner and weaker. Fractures appear. Large chunks drop into the ocean and float away to warmer parts of the ocean, and melt. Their melting raises the mean sea level. Thus, the problem is not so much the heating of the Antarctic plateau, but the rise in the ocean temperature bordering Antarctica. By decreasing summer sunlight on the ocean at the coastline, the balance between summer melting and winter ice accumulation may be reduced enough to reverse the present trend. An array of reflectors located appropriately over the coastline of Antarctica in summer will assist in this process.
In prior art, Kawai [13] has suggested ground-based reflectors along the coast on the glacier edge to reduce solar this. However, the high installation cost and the dubious environmental acceptability of such reflectors are not addressed. Also such reflectors cannot be installed beyond the stable edge of the glacier or rock. In particular, they do not reduce sunlight falling on the sea ice bordering the coast.
The present invention offers a scalable, automatic-controlled and remotely deployed solution that is superior to installing ground based reflectors in Antarctica. The installation of a ring of such upper atmosphere reflector arrays around the polar circle is named the Polar Necklace. As the Antarctic summer ends, the reflectors can be drifted and redeployed to follow the summer Sun using the small solar-powered rotors.
Even in summer, the polar Sun is quite shallow, and hence reflectors must incline at a steep angle to be normal to sunlight. The Balloon Beanies are well suited to this problem, since the lift needed from the balloons is the same at any inclination.

Semi-Annual Migration

The reflectors can be moved constantly to best reflect sunlight. Unlike birds that wait for late autumn and spring before undertaking long flights, the reflectors can be drifted slowly and continuously to track the midsummer Sun daily as the seasons change over the planet. The drift speed required is miniscule, well under 1 m/s according to calculations presented in [17] and [18]. The Balloon Beanies can be used for this purpose by using small solar-powered propellers during daytime, and an edgewise glide at night. This flight is in a manner that is superficially similar to that of a frisbee toy.

Reversing Deployment as Needed

Unlike space-based concepts, the Glitter Belt can be deployed one at a time, brought down and individual elements can be replaced as required. Each swarm of sheets can be slowly and benignly directed to descend through the atmosphere, to touch down either on land or in water. Except for the sheets that may get damaged, most of the rest of the vehicles may be recovered.
The Glitter Belt invention referenced to Prior application [Ser. No. 16/140,161] is to place ultra-light reflector sheets, not in orbit in Space, but at the edge of the atmosphere. Above 24,000 meters (roughly 80,000 feet) altitude, the sky appears black to the unaided eye, from horizon to horizon. This is true even in bright sunlight. This is because there is not sufficient air to scatter the light and give the blue appearance that is seen from below.
The above-referenced sheets can be equipped with sufficient structure and means for automatic guidance, navigation and control, so that they can fly in autonomous mode with only minor supervision from ground-based controllers. Over most of the planet Earth, wind speeds and weather variations are small at such altitudes where the invention is to be flown in its usual application.

Merits of the Present Invention

The advantages of the Glitter Belt concept compared to the Space-based reflectors of prior art, are obvious. The energy required to place the reflectors at the selected altitude is less than two parts in a million (2/1,000,000) of that required to place the same area of reflectors in Earth orbit in Space. On the other hand, objects that are placed in orbit require very little additional energy to stay in orbit for a long time, whereas vehicles in the atmosphere need power addition to counter winds and stay in position. However, sunlight provides plentiful and inexhaustible energy to power such vehicles. Unlike Space vehicles which incur high launch costs, the Balloon Beanie vehicles can be launched from the ground almost anywhere on a clear morning, to climb to the required altitude. They can be repositioned easily by means of small rotary propellers, compared to the high expenditure of energy required to change the orbital plane of a spacecraft. The aerostatically supported reflector vehicles can be launched one or severally at a time. They can be removed from flight when it is so required. Such removal can be accomplished with safe recovery. The vehicles can be launched again if desired.
Reflective sheets of aluminized Mylar, as an example, reflect nearly 100% of broadband sunlight. With the reflectors located at a nominal altitude, for instance near 30,480 meters (100,000 feet), almost all of the reflected radiation will exit permanently into Space. Higher or lower altitudes are also possible. In comparison, a ground-based reflector will only send about 50% of solar radiation back into Space, with most of the remaining 50% being absorbed in the lower atmosphere.
Because they avoid allowing sunlight to be absorbed through a round-trip through the atmosphere, high-altitude reflectors are roughly twice as effective per unit area as ground-based reflectors. They do not need permission from landowners. They can float above the oceans and icecaps as well. They are not affected by cloud cover and receive direct sunlight for more hours per day than ground-based reflectors. The ability to drift with the seasons to say under the summer sun, makes them more efficient than ground-based reflectors.

Need, Advantages, Feasibility and Differences Relative to Prior Art

Several references below describe prior art and basic knowledge that are applied in the new use described in the present invention.
Solar-powered aircraft in general are described in References [19] and [20]. These generally show that sufficient solar power can be absorbed during the daytime to enable a heavier-than-air aircraft to stay aloft in the atmosphere using aerodynamic lift. Patent US 2016/0144969 A1 [Reference 19] describes a high-aspect ratio wing with vertical winglets and multiple electrically driven propellers. This is generally similar to the NASA Solar Pathfinder and its derivatives. More recent inventions from Airbus Industries describe newer versions of high-altitude, long-endurance aircraft that bear several similarities to the PathFinder concept, but still use energy storage means to survive the night-time gliding period. Unlike all of these prior art, the present invention does not have to use stored electrical energy to sustain night-time altitude because the aerostatic lift continues during the night.
U.S. Pat. No. 4,415,133A [Reference 20] describes a solar-powered aircraft. The idea of keeping the solar panels perpendicular to the Sun by flying the aircraft at a large bank angle is considered there. The Balloon Beanie example of the present invention renders banked flight unnecessary. The mass distribution can be changed to tilt the sheet to a different orientation when the balloon is static above a given location. Alternatively or complementarily, the gas pressure to the different balloons can be altered. This will change the volumes of the different balloons and thus the individual aerostatic lift of each This can assist in changing the orientation of the sheet. The cost and complexity of flying complex maneuvers to reflect more light, has to be traded against the cost of manufacturing and launching more sheets. In one implementation, the first vehicles may be equipped with more sophisticated controls to maximize effectiveness, while mass production of sheets and carrier vehicles is ramping up.
U.S. Pat. No. 3,452,464 [Reference 21] describes a reflective Mylar sheet. Patent US20140252156A1 [Reference 22] describes a High Altitude Aircraft, Aircraft Unit and Method for Operating an Aircraft Unit, generally similar to Reference [23] in design but incorporating thin Mylar sheets for covering the structure. U.S. Pat. No. 9,475,567B1 [Reference 24] describes a double-layered balloon for the purpose of reducing gas leakage. It does not anticipate placing a solar-powered pump to evacuate and re-use the gas from between the two layers, as is specified above and claimed in the present invention.
Technology that is relevant to the Glitter Belt architecture has been developed and presented by several researchers and inventors. References [24] and [25] describe the technology of solar sails. These promise to reduce the thickness and the areal density of the reflective sheets by orders of magnitude. Hence their future use is an obvious extension of the use of Mylar sheets used in one implementation of the present invention.
Reference [26] defines the International Standard Atmosphere, used in calculations for the present invention. Reference [27] describes the performance achieved with the NASA Pathfinder aircraft. Unlike the Pathfinder, the Balloon Beanie does not require auxiliary energy storage or other night-time power generation means.
References [28] and [29] describe engineering aspects of aircraft that are intended for long-endurance flight in the upper atmosphere, including the use of solar-powered airplanes. These aspects are mostly included in the design of the Pathfinder and related aircraft. Again, the need for auxiliary energy storage forces these aircraft to have significantly higher wing loading than the implementations of the Glitter Belt invention. In addition they require the carriage of concentrated loads such as fuel cells, which imposes additional requirements on the structural strength and thus the weight of these aircraft.
Reference [30] presents experience from communications with a high-altitude solar-powered vehicle. This shows that remote operation of such vehicles has been studied, and is feasible. References [31], [32] and [33] discuss technical aspects of flying several aircraft or birds in close formation. Such flight has been used since the large bomber formations of World War II to increase range, while aerobatic exhibitions demonstrate extremely close formation flight even at very high speeds. Thus it is clear that formation flight in swarms, and communication with high-altitude swarms, are both solvable problems. Reference [34] describes the properties of the material used to make high-altitude balloons in the 1960 s.

SPECIFIC EXAMPLES, MAJOR COMPONENTS AND ALTERNATIVES

Example 1: Balloon Beanie

Referring to FIG. 3, the Balloon Beanie, aerostatically supported reflector sheet concept, is shown with 5 balloons. The balloons (2) are deployed from the ground, and they lift the central sheet (3) to the desired altitude. The inflated rim (4) holds the sheet steady and carries solar cells, while small rotors (5) driven by solar power provide control and steering power. The arrangement of the balloons can be varied depending on the desired sheet shape and orientation. In FIG. 3, an optional central balloon (6) is shown located under the sheet as an illustration of configurations that are possible. This could incorporate the telemetry system. In another implementation rigid or semi-rigid spokes could be incorporated to hold the sheet and rotors.
Solar-powered rotors around the periphery provide trim, counter winds, and allow the twice-a-year migration. Some energy storage may be added to provide emergency power at night. The issue of hydrogen leakage is addressed with a double-shell provided with an evacuation pump in between. The shell structure can be made with present materials, but future implementations may offer opportunities to use advanced ultralight materials such as Silica AeroGel. The reflective coated Mylar membrane of the balloons reduces the tilt needed to reflect evening, morning and polar summer sun. The size of the inner hydrogen-inflated shell can vary, constrained by the dimensions of the outer shell, so that the risk of bursting when exposed to direct sunlight is alleviated.
Various configurations are anticipated for the Balloon Beanie. The configuration shown in FIG. 3 is simplified for explanation. Other implementations may use different configurations and shapes of the balloons or integrate them with the sheets in different ways depending on the nature of the deployed mission, and the expected trajectory of the Sun through the azimuth.

CONCLUSIONS

As described above, the Glitter Belt invention presents a low-cost, scalable and reversible method and apparatus which can be deployed rapidly to reduce the rate at which the temperature of the Earth's atmosphere is rising. It reduces the solar irradiance to the atmosphere. It is anticipated that initial deployment tests using full-scale or small-scale models will establish the performance and effects of the invention, permitting rapid scaling up. It is understood that a large number of reflectors will be needed to significantly reduce the rate of atmospheric heat retention. High impact can be obtained early with concepts such as Polar Necklace, and summer-following sheet swarms. It is also anticipated that the reflector sheet systems may be combined with other uses, thereby improving their economic viability.
The Balloon Beanie invention as an implementation of the Glitter Belt invention proves that at least one near-term solution exists, for the problem of Global Climate Change. It is possible to reverse atmospheric heating back to desired levels. Such a large change will require a large number of reflectors, to be deployed, over a period of 1 or two decades, with the participation of many nations around the world. Unlike prior concepts, the Glitter Belt is not known to cause any adverse effects. All the deployed systems may be removed from high altitude and the material recovered on demand. These aspects may be verified by actual testing which can proceed during the initial phase before significant expenditure of time or financial resources. In these respects and others, the Glitter Belt invention provides advantages superior to those of any prior inventions.

REFERENCES

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Claims

1. (canceled)

2. Method of arranging reflective sheets above the coastline of the Antarctic continent such that summer heating of the sea ice off the coast is reduced.

3. Method of supporting reflective sheet at high altitude for extended periods by aerostatic means, where

(a) balloons inflated with hydrogen are attached to a tubular structure which is attached to the periphery of the sheet;

(b) in one embodiment hydrogen leakage from an aerial vehicle is reduced, said method comprising of extracting hydrogen from between two shells of a double-shelled balloon envelope, by means of a vacuum pump, and pumping it back into inner gas envelope of said double-shelled balloon envelope.

TABLE 1 Summary of Claims Status: Complete Listing of All Claims Ever Presented, With Status and Amended Version No. (Original) Status (Amended) if any 1 A method to reduce solar Deleted irradiance to the atmosphere of Earth by aerostatic means, comprising of 1.1 launching multiple reflectors from the ground by the use of lighter-than-air vehicles; 1.2 deploying said reflectors in the upper atmosphere; 1.3 maintaining the altitude of said reflectors above a specified altitude through numerous days and nights; and holding said reflectors in a stretched form with a smooth surface. 2 Method of Claim 1 where Amended Method of arranging reflective sheets are arranged reflective sheets above above the South Polar region the coastline of the of Earth in order to alleviate Antarctic continent such the rise in the ocean that summer heating of temperature at the edge of the the sea ice off the coast Antarctic Continent in is reduced. summer. 3 Method of supporting Amended Method of supporting reflective sheets at high reflective sheet at high altitude for extended altitude for extended periods by aerostatic periods by aerostatic means, including: means, where 3.1 an embodiment where (a) balloons inflated with balloons inflated with hydrogen are attached to hydrogen are attached to a a tubular structure which tubular structure which is is attached to the attached to the periphery periphery of the sheet; of the sheet; 3.2 an embodiment which (b) in one embodiment includes reducing hydrogen hydrogen leakage from leakage from each balloon. an aerial vehicle is by extracting hydrogen from reduced, said method between the two shells of a comprising of extracting double-shelled balloon hydrogen from between envelope, by means of a two shells of a double- vacuum pump, and shelled balloon envelope, pumping it back into the by means of a vacuum inner gas envelope. pump, and pumping it back into inner gas envelope of said double- shelled balloon envelope.