WO1999026840A1

WO1999026840A1 - Airship with neutral buoyancy fuel bladder

Info

Publication number: WO1999026840A1
Application number: PCT/US1998/023228
Authority: WO
Inventors: Richard Coleman; Lathan Collins
Original assignee: Richard Coleman; Lathan Collins
Priority date: 1997-11-21
Filing date: 1998-11-19
Publication date: 1999-06-03
Also published as: US5890676A; AU1582299A

Abstract

A neutral buoyancy fuel bladder (25) uses hydrogen and oxygen to power an airship (20). The neutral buoyancy fuel bladder (25) includes a fuel cell (33), electrolyzer (32), means for storing hydrogen (26), means for storing oxygen (29), and means for storing water (27). The fuel cell (33) uses the hydrogen and oxygen to create heat, water, and current flow. An energy source (10) transmits a beam (70) to an energy receiving unit (24) on the airship (20) where the energy from said beam (70) is used to power said airship (20), and replenish the supply of hydrogen and oxygen.

Description

AIRSHIP WITH NEUTRAL BUOYANCY FUEL BLADDER

Field of the Invention

The present invention relates to power systems for airships, and in particular, power

systems that allow airships to remain aloft for indefinite periods of time.

Background of the Invention

A typical airship is comprised of a hull which can be either non-rigid, semi-rigid, or rigid.

A non-rigid airship nominally comprises a pressurized, gas tight fabric envelope constructed of

several layers of impregnated cloth, and it relies upon internal pressure to enable it to endure

compressive or bending loads. A rigid airship comprises a hull normally constructed of metal or

wood which is covered with a doped fabric to form the airship's envelope. A rigid airship does

not depend on internal pressure for strength and stability. Semi-rigid airships contain the features

of both rigid and non-rigid airships.

An airship achieves most of its lift from the lighter-than-air gas contained within its

envelope. The two most frequently used gases are hydrogen and helium, although helium is more

commonly used because it is readily available, nonflammable and inert. The mobility of an

airship comes from its propulsion system which may include an internal combustion engine, a

fuel source, and a propeller and rudder system. One of the major advantages of an airship is its

ability to remain aloft for extended periods of time without the need for returning to the earth for

refueling as is required by conventional aircraft. This ability to remain aloft for extended periods

of time results from the fact that an airship s loft is achieved primarily by the helium or hydrogen

contained within its envelope, not from any lift resulting from its propulsion system. While an - airship has the ability to remain aloft for an extended period of time, such time period is not

unlimited, but rather is limited by the airship's fuel capacity.

Summary of the Invention

The present invention relates to a novel system for generating power to propel an airship

and for aiding in the buoyancy of the airship. The novel system employs a neutral buoyancy fuel

bladder, when used in conjunction with an energy transmission source which supplies energy to

the airship without the airship renaming to the earth, the airship can remain aloft for an indefinite

period of time. The ability of an airship powered by the neutral buoyancy fuel bladder to remain

aloft for an indefinite period of time makes such an airship ideally suited for telecommunications

and/or remote surveillance.

An airship upon which a neutral buoyancy fuel bladder may be installed is comprised of a

hull or envelope, a standard propulsion system, propellers, and a rudder system as a means of

navigation. The main envelope clothe hull is filled with helium to supply the bulk of the

buoyancy to the airship, although the neutral buoyancy fuel bladder also supplies some

buoyancy. The neutral buoyancy fuel bladder comprises a separate compartment within the hull

of the airship, and it is divided into two sections by a diaphragm. One section of the neutral

buoyancy fuel bladder contains hydrogen and the other section contains water in the form of

steam. The neutral buoyancy fuel bladder is insulated to maintain the water in the form of steam

faith minimal energy input. The section of the neutral buoyancy fuel bladder which contains the

hydrogen may also contain an electrolyzer and a fuel cell. Alternatively, the electrolyzer and fuel

cell may be located outside or the neutral buoyancy fuel bladder.

The airship further contains a pressurized oxygen container and an energy receiving unit,

such as a rectifying antenna (rectenna) for receiving power from the energy transmission source. The energy receiving unit receives a beam or other laser form from the energy transmission

source which is normally located on the surface of the earth. Such a beam may be a polarized

beam from a microwave transmitter Alternatively, the energy receiving unit can be positioned on

the airship to receive power from another airship or other extraterrestrial source. The energy

receiving unit receives the beam, and uses the energy therefrom for two purposes. First, the

beam supplies energy directly to the airship for the propulsion system and for other energy needs.

Second, the beam powers the electrolyzer which converts the steam stored in the neutral

buoyancy fuel bladder into its component parts of hydrogen and oxygen. The hydrogen is stored

in one section of the neutral buoyancy fuel bladder, and the oxygen is stored in the pressurized

oven storage container.

When the airship is not in range or the energy transmission source, the fuel cell provides

power to the airship. The fuel cell uses the hydrogen and oxygen to produce heat, water, and

current flow. The water is stored as steam in the neutral buoyancy fuel bladder for later

conversion back to hydrogen and oxygen, the heat is used to maintain the water as steam, and the

current flow is used to power the airship. The water is kept in the form of steam because it, along

with the hydrogen in the other section of the neutral buoyancy fuel bladder, aids in the buoyancy

of the airship.

The above-described system permits the airship to use the hydrogen and oxygen as a fuel

source and travel to an area which is remote from the energy transmission source. The airship

system could also be employed in a geosynchronous orbit over the power beam and could

receive power either continuously or intermittently. In either instance, the airship may serve a

telecommunication or remote surveillance function. When positioned at a remote site, and the

airship's supply of hydrogen and oxygen needs replenishing, the airship travels back to the area

of the energy transmission source for "refueling", i.e. receiving power from the energy transmission source and converting the steam into its component parts of hydrogen and oxygen.

Multiple airships and energy transmission sources could be used thereby allowing at least one

airship to constantly remain aloft over an area remote from the ground station. Such a setup

would be particularly beneficial if the airship must remain aloft over an area, such as a densely

populated city, where it may not be convenient to place an energy transmission source.

Consequently, it is an object of the present invention to provide an airship with a power

system which allows it to remain aloft for an indefinite period of time.

It is another object or the present invention to provide and replenish the power within said

airship via an energy transmission source.

It is a further object of the invention to provide said airship with a fuel cell on board to

power said airship when it is not within range of said energy transmission source.

It is a still further object of the invention to use said airship for telecommunications,

including, but not limited to, data, Internet access, video and voice.

It is another object of the invention to use said airship for remote surveillance, remote

reconnaissance, and remote surveying.

Brief Description of the Drawings

Figure 1 is an illustration of the neutral buoyancy fuel bladder of the present invention

located within an airship.

Figure 2 is a detailed illustration of the neutral buoyancy fuel bladder of the present

invention.

Figure 3 is a detailed illustration of a fuel cell used in the present invention. Detailed Description of the Preferred Embodiment

An airship 20 in connection with which the present invention may operate is illustrated in

Figure 1. The airship 20 can be of the non-rigid, semi-rigid, mid, or heaver-than-air type. It

comprises a hull formed by an envelope 21 which serves to contain helium or hydrogen, and

further comprises rudders 22, and propellers 23. On the belly of the airship 20 is an energy

receiving unit 24, which for the purposes of this detailed description will be a rectifying antenna

(rectenna). In lieu of being placed on the belly of the airship, the rectenna 24 can also be located

within the confines of airship 20. In another embodiment, a solar panel 30 is located on the top

writhe airship 20. Within the hull of the airship 20 is a neutral buoyancy fuel bladder 25. The

neutral buoyancy fuel bladder 25 comprises a compartment 26 which stores hydrogen, and a

compartment 27 which stores steam. Compartment 26 also contains an electrolyzer 32 and a fuel

cell 33. In an alternative embodiment, the electrolyzer 32 and the fuel cell 33 are located outside

of the neutral buoyancy fuel bladder 25. The neutral buoyancy fuel bladder 25 is surrounded by

an insulating layer 34, and compartments 26 and 27 are separated by a diaphragm 28. In a

preferred embodiment, insulating layer 34 consists of several layers containing dead air space as

the insulating medium. Also contained within the hull is a pressurized oxygen storage container

29.

Figure 2 illustrates in more detail the relationship between the neutral buoyancy fuel

bladder 25, the fuel cell 33, the electrolyzer 32, and the oxygen storage tank 29. Figure 2 also

illustrates a heat exchanger 35 and a condenser 36, both of which are in communication with

compartment 27. Figure 2 further illustrates a power-out line 37.

The helium or hydrogen in the main portion of the envelope 21 provides the bulk of the

buoyancy to the airship 20 although the steam in compartment 27 also provides some buoyancy.

When the airship 20 is airborne, a beam 70 is transmitted to it from an energy transmission source 10 preferably located on the surface or the earth. One type or energy transmission source

that can be used is a microwave transmitter. The beam 70 is received by the rectenna 24.

Appropriate levels of energy and frequency ranges for a similar microwave/aircraft system are

disclosed in U.S. Patent No. 5,503,350, which is incorporated herein by reference. The energy

from the beam 70 is used for two purposes. First, it is used to directly power the propulsion

system of the airship 20. In such a case, power received by the rectenna 24 is supplied directly to

an electric motor or other means which is used to drive the propeller 23. The energy received by

the rectenna 24 can also be stored for later use, for example in an on-board battery. Second, the

energy from the beam 70 is used to convert the steam m compartment 27 into its component

parts of hydrogen and oxygen. The resulting hydrogen is stored in compartment 26, and the

oxygen is stored in pressurized container 29.

When the airship 20 is not in the range of the energy transmission source 10, the airship

20 is powered by fuel cell 33. Figure 3 illustrates that the fuel cell 33 consists of three basic

parts—the hydrogen-in system 41, the proton exchange membrane 42 (PEM), and the

oxygen/water removal system 43. Hydrogen from compartment 26 enters into the hydrogen-in

portion 41 or the fuel cell 33. The hydrogen comes into contact with the PEM 42 which performs

two functions. It breaks the molecular hydrogen (H₂) into atomic hydrogen (H⁺) and transfers the

atomic hydrogen to the oxygen side 43 of the fuel cell 33. Second, the PEM 42 collects the

electrons given off from the disassociation of the hydrogen molecule as direct current to power

the airship via power-out line 37. In addition to powering the airship 20 with direct current from

the fuel cell 33, power can be generated by an on-board thermal engine or from the solar panel

30.

On the oxygen side 43 of the fuel cell 33, the molecular oxygen (O₂) comes into contact

with the PEM 42 where it takes up four electrons, thereby being converted to atomic oxygen (2O ²). The atomic oxygen and hydrogen then react to produce heat and two molecules of water.

The reactions are illustrated below in equations (1), (2) and (3).

(1) 2H₂ → 4H⁺ + 4e^"

(2) O₂ + 4e^" - 2O-²

(3) 4H⁺ + 2O^'2 → 2H₂O

The water and heat produced by the above reactions are transported to heat exchanger 35

contained within compartment 27 of the neutral buoyancy fuel bladder 25. The heat exchanger

operates at 180° F and 45 psia. The steam side of the heat exchanger 35 operates at 100° F and

0.65 psia. The temperature difference between the heat exchanger 35 and the steam drives the

transfer of heat from the heat exchanger 35 to the steam.

The waste water from the fuel cell is at 180° F and 45 psia. When the waste water is

injected onto the outside or the heat exchanger a fraction of the water flash evaporates to produce

saturated steam at 0.65 psia and 90° F (the boiling point or water at that pressure). The remaining

waste water is saturated water at 0.65 psia and 90° F. This water, in contact with the heat

exchanger, is evaporated and then heated to 100° F resulting in all the water becoming steam.

When the airship 20 is within range of energy transmission source 10, the power from the

energy transmission source 10 is used to drive the above reactions in the reverse direction to

produce H₂ and O₂. Specifically, the condenser 36 condenses the steam in compartment 27 into

water and supplies the water to the electrolyzer 32. The electrolyzer 32 splits a molecule of water

into an oxygen atom (O^"2) and two hydrogen atoms (2H⁺). The oxygen atom releases two

electrons to become a molecule of oxygen (O₂), and the two hydrogen atoms each take up an

electron to make a hydrogen molecule (H₂). The hydrogen is stored in compartment 26, and the

oxygen is stored in pressurized oxygen container 29. The hydrogen and oxygen can then be used by the fuel cell 33 to produce power when the airship 20 is not within range of energy

transmission source 10. The driving or the above reactions in the reverse direction to produce

oxygen and hydrogen is referred to as "charging" the fuel cell 33.

The heat exchanger 35 has three modes of operation depending upon the amount of heat

created or consumed. In the steady state balanced operation, all the thermal waste energy is put

into the neutral buoyancy fuel bladder 25 to maintain the water as steam and to overcome the

heat loss through the wall of the neutral buoyancy fuel bladder 25. If the amount of heat

produced is in excess of the heat lost through the wall of the bladder, an external heat exchanger

is used to dissipate the excess heat. If the heat loss through the wall of the neutral buoyancy fuel

bladder is greater than the waste heat from the fuel cell 33,. heat must be added to the system by

means of a burner to combust the hydrogen and oxygen thereby producing steam and excess

heat. The excess heat is supplied to the neutral buoyancy fuel bladder 25 to maintain the water

within it in the form of steam. Heat from solar panel 30 can also be used to maintain the steam in

the compartment 27.

The airship 20 with neutral buoyancy fuel bladder 25, because of its ability to "refuel"

without returning to the earth, can remain aloft for indefinite periods of time. This feature is

especially advantageous if the airship 20 is used for telecommunications or surveillance.

Although particular embodiments of the invention have been described, it will be

apparent to those skilled in the art, and it is contemplated, that variations and/or changes in the

embodiments illustrated and described herein may be made without departure from the present

invention. Accordingly, it is intended that the foregoing is illustrative only, not limiting, and that

the true spirit and scope of the present invention will be determined by the appended claims.

Claims

Claims:

1. A neutral buoyancy fuel bladder comprising:

an outer envelope forming said bladder;

a first compartment within said bladder, said first compartment containing hydrogen;

a second compartment within said bladder, said second compartment containing water in

the form of steam;

means for storing oxygen;

a diaphragm within said bladder, said diaphragm separating said first compartment from

said second compartment;

a condenser in communication with said second compartment, said condenser

transforming said steam from said second compartment into water;

an electrolyzer, said electrolyzer receiving said water from said condenser and

disassociating said water into hydrogen and oxygen molecules;

a fuel cell, said fuel cell receiving hydrogen from said first compartment and

oxygen from said means for storing oxygen, and said fuel cell producing heat, water and current

flow from said hydrogen and said oxygen; and

a heat exchanger in communication with said second compartment, said heat

exchanger dissipating heat produced by the hydrogen and oxygen reactions in said fuel cell.

2. The neutral buoyancy fuel bladder according to claim 1, wherein said bladder is

insulated.

3. The neutral buoyancy fuel bladder according to claim 1, wherein said hydrogen

produced by said electrolyzer is stored in said first compartment.

4. The neutral buoyancy fuel bladder according to claim 1, wherein said oxygen

produced by said electrolyzer is stored in said means for storing oxygen.

SUBSI I╬ôU ╬ôE SHEET (RULE 26)

5. The neutral buoyancy fuel bladder according to claim 1, wherein said heat exchanger

further supplies neat to said second compartment thereby maintaining the water in the form of

steam in said second compartment.

6. The neutral buoyancy fuel bladder according to claim 1 , wherein said means for

storing oxygen is a pressurized oxygen container.

7. The neutral buoyance fuel bladder according to claim 2, wherein said insulation laver

comprises two or more layers of dead air space.

8. A system for powering an airship said system comprising:

an energy transmission source;

an energy receiving unit located on said airship; and

a neutral buoyancy fuel bladder located on said airship, said neutral buoyancy fuel

bladder comprising:

an outer envelope forming said bladder;

a first compartment within said bladder, said first compartment containing

hydrogen;

a second compartment within said bladder, said second compartment

containing water in the form of steam;

means for storing oxygen;

a diaphragm within said bladder, said diaphragm separating said first

compartment from said second compartment;

a condenser in communication with said second compartment, said condenser

transforming said steam from said second compartment into water;

an electrolyzer, said electrolyzer receiving said water from said condenser

and disassociating said water into hydrogen and oxygen molecules; a fuel cell, said fuel cell receiving hydrogen from said first compartment

and oxygen from said means for storing oxygen, and said fuel cell producing heat, water and

current flow from said hydrogen and said oxygen; and

a heat exchanger in communication with said second compartment, said heat

9. The system for powering an airship of claim 8, wherein said energy transmission

source is a microwave transmitter.

10. The system for powering an airship of claim 8, wherein said energy receiving unit

is a rectifying antenna.

11. A method to power an airship comprising the steps of:

transmitting a beam to said airship from an energy transmitting source;

receiving said beam with an energy receiving unit located on said airship;

disassociating water contained within a neutral buoyancy fuel bladder on said airship into

hydrogen and oxygen molecules;

storing said hydrogen and oxygen molecules in separate containers on said airship; and

powering said airship with energy from said energy transmitting source.

12. The method for powering an airship according to claim 11, further comprising the

steps of:

transporting said airship to an area outside the range of said energy transmitting source

using said hydrogen and oxygen in a fuel cell on said airship; and

transporting said airship back to said energy transmitting source to replenish said

hydrogen and said oxygen by disassociating water with an electrolyzer.

13. The method to power an airship of claim 11, wherein said energy transmission source

is a microwave transmitter.

14. The method to power an airship of claim 11, wherein said energy receiving unit is a

rectifying antenna.