U.S. patent application number 13/275493 was filed with the patent office on 2013-04-18 for hydrogen storage system.
The applicant listed for this patent is Jorg Wellnitz. Invention is credited to Jorg Wellnitz.
Application Number | 20130092561 13/275493 |
Document ID | / |
Family ID | 47215477 |
Filed Date | 2013-04-18 |
United States Patent
Application |
20130092561 |
Kind Code |
A1 |
Wellnitz; Jorg |
April 18, 2013 |
Hydrogen Storage System
Abstract
A Hydrogen storage system comprising storage elements coupled to
each other to form one or more containers disposed in a space
having a volume V where the volume of each of the storage elements
is much smaller than the volume V resulting in the storage elements
experiencing reduced stress at their inner surfaces. Thus, Hydrogen
can be stored at relatively high pressure within these storage
elements due to the reduced stress experienced by their inner
surfaces. Consequently, materials having relatively lower tensile
strength and stiffness can be used to construct the storage
elements of the Hydrogen storage system. Further, the storage
elements can be shaped and sized to conform to a volume of space
having an arbitrary shape and dimensions.
Inventors: |
Wellnitz; Jorg;
(Walting/Gungolding, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wellnitz; Jorg |
Walting/Gungolding |
|
DE |
|
|
Family ID: |
47215477 |
Appl. No.: |
13/275493 |
Filed: |
October 18, 2011 |
Current U.S.
Class: |
206/.6 |
Current CPC
Class: |
F17C 2203/0621 20130101;
F17C 2203/0663 20130101; F17C 2270/0178 20130101; F17C 2201/0104
20130101; F17C 2203/0643 20130101; F17C 2203/0646 20130101; F17C
2223/036 20130101; F17C 2201/0147 20130101; F17C 2209/2154
20130101; F17C 2205/0352 20130101; F17C 2203/0604 20130101; F17C
2260/018 20130101; F17C 2201/0138 20130101; F17C 2205/0146
20130101; F17C 2260/036 20130101; F17C 2270/0168 20130101; F17C
2270/0581 20130101; F17C 1/005 20130101; Y02E 60/32 20130101; F17C
2201/0157 20130101; F17C 2221/012 20130101; Y02E 60/321 20130101;
F17C 2203/0648 20130101 |
Class at
Publication: |
206/6 |
International
Class: |
B65D 85/00 20060101
B65D085/00 |
Claims
1. A Hydrogen storage system to be disposed within a defined space
of volume V, the hydrogen storage system comprising: N storage
elements coupled to each other to form one or more containers that
fit within the defined space where each storage element has a
volume equal to a fraction of the volume V and N is an integer
equal to 1 or greater.
2. The Hydrogen storage system of claim 1 where each of the storage
elements has a volume and shape that are the same as other storage
elements.
3. The Hydrogen storage system of claim 1 where some or all of the
storage elements have different volumes and shapes.
4. The Hydrogen storage system of claim 1 where each of the storage
elements has an inner layer made of hydrogen impermeable material
and an outer layer made from a composite material.
5. The Hydrogen storage system of claim 1 further comprising one or
more other containers not made from coupled storage elements and
the one or more other containers are positioned proximate the one
or more containers such that both types of containers fit within
the defined space of volume V.
6. The Hydrogen storage system of claim 1 where the storage
elements comprise long cylinders, short cylinders and bent
cylinders all of which have an inner layer with equal inner and
outer diameters and with corresponding inner and outer surfaces and
where such inner layer is made from aluminum of a certain
thickness.
7. The Hydrogen storage system of claim 6 where the bent cylinders
are curved cylinders with a curve radius equal to kD.sub.0 where k
is an integer equal to a real number greater than zero and D.sub.0
is the outer diameter of the bent cylinder.
8. The Hydrogen storage system of claim 7 where k is equal to
2.
9. The Hydrogen storage system of claim 6 where the long cylinders,
short cylinders and bent cylinders are coupled to form a serpentine
cylindrical container having the inner layer and an outer layer
made of a composite material adhered to the outer surface of the
inner layer.
10. The Hydrogen storage system of claim 9 where the outer layer
comprises resin applied to the outer surfaces of the inner layer
and Basalt fibers wound onto the resin applied to the outer
surfaces of the inner layer at a 45 degree angle with respect to a
longitudinal axis of each of the coupled storage elements.
11. The Hydrogen storage system of claim 9 where the outer layer
comprises resin applied to the outer surfaces of the inner layer
and Innegra fibers wound onto the resin applied to the outer
surfaces of the inner layer at a 45 degree angle with respect to a
longitudinal axis of each of the coupled storage elements.
12. The Hydrogen storage system of claim 9 comprising a plurality
of serpentine containers positioned proximate each other to fit
within the defined space of volume V.
13. The Hydrogen storage system of claim 6 where the long
cylinders, short cylinders and bent cylinders are coupled to form
one or more serpentine cylindrical containers and one or more other
containers not formed from the long cylinders, short cylinders and
bent cylinders and all of the containers are positioned proximate
each other to fit within the defined space of volume V.
14. The Hydrogen storage system of claim 13 where the one or more
other containers are spherical containers.
15. The Hydrogen storage system of claim 6 where each of the
storage elements has a circular cross section profile.
16. The Hydrogen storage system of claim 6 where the storage
elements have different cross section profiles.
17. The Hydrogen storage system of claim 1 where the storage
elements are coupled to each other via a common distribution
conduit.
18. The Hydrogen storage system of claim 17 where the storage
elements are U-shaped cylinders.
19. The Hydrogen storage system of claim 17 where the storage
elements are capsules.
20. A Hydrogen storage system to be disposed within a defined space
of volume V having an arbitrary shape and dimensions, the hydrogen
storage system comprising: N storage elements each having a volume
equal to or less than V N ##EQU00008## where N is an integer equal
to 2 or greater and the storage elements are coupled to each other
to form a container that conforms to the shape and dimensions of
the defined space.
21. The Hydrogen storage system of claim 20 where the container
comprises one or more sections coupled to each other and positioned
in relatively close proximity to each other or are attached to each
other.
22. The Hydrogen storage system of claim 21 where each of the
sections comprises a plurality of the N storage elements coupled
together.
23. The Hydrogen storage system of claim 20 where each of the
storage elements is made from a Hydrogen impermeable material
having an outer surface to which a composite material is
adhered.
24. The Hydrogen storage system of claim 23 where the composite
material comprises resin and fibers made from Basalt rock
25. The Hydrogen storage system of claim 23 where the composite
material comprises resin and fibers made from Innegra.
26. A Hydrogen storage system to be disposed within a defined space
of volume V having an arbitrary shape and dimensions, the hydrogen
storage system comprising: N storage elements each having a volume
equal to or less than V N ##EQU00009## where N is an integer equal
to 2 or greater and the storage elements are coupled to each other
to form one or more containers that fit within the defined
space.
27. The Hydrogen storage system of claim 26 where the one or more
containers are coupled to each other.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to hydrogen storage
systems for a defined space and more particularly relates to the
architecture, size, shape and positioning of such systems for a
defined space in vehicles or in storage areas.
[0003] 2. Description of the Related Art
[0004] Hydrogen is increasingly becoming a fuel used in all types
of vehicles including bi-fuel vehicles where the other fuel is
gasoline. There is however a key practical consideration associated
with the use of Hydrogen as a fuel for vehicles. The key
consideration is the storage of the hydrogen fuel itself; this
consideration raises several issues. In particular, the size, cost
of manufacture, and weight of hydrogen tanks are issues that
complicate the design and practicability of such tanks Also, the
storage mass of the Hydrogen is itself a key consideration.
[0005] A first issue is the size of the tanks relative to the space
allocated to them in vehicles. Current hydrogen fuel tanks store
hydrogen at a typical pressure of 200-350 bars where a "bar" is a
unit of pressure defined in terms of kilopascals; that is 1 bar is
equal to 100 kilopascals or 100 kPa; 1 kPa.ident.1000 Pa; 1
MPa.ident.1,000,000 Pa. The "pascal" is a well-known defined unit
for the measurement of pressure, internal pressure, stress, Young's
modulus (measure of stiffness of an isotropic elastic material),
and tensile strength. At a pressure in the range of 200-350 bars,
the amount of Hydrogen needed to be stored in a Hydrogen tank to be
comparable to the energy content of a conventional gasoline tank
often makes the size of the Hydrogen tank impractically large and
in many cases impossible to install in the space allocated for the
tank or in available space in the vehicle. Often the only available
space is the trunk of an automobile and in many cases the size of a
200-350 bar tank would, for many vehicles, use virtually the entire
trunk space reducing the overall usefulness of the vehicle.
Typically, current hydrogen tanks have dimensions that are nearly
the same as the dimensions of the space allocated to them. For
example, many tanks occupy most if not the entire space of a trunk
of a vehicle, which is the space that is usually allocated to such
tanks
[0006] Current Hydrogen tanks are often cylindrical in shape and
thus their design considerations are based on well known laws of
physics regarding the internal pressure experienced by their inner
surfaces when such cylinders contain gas, liquid or other matter.
The effect of the internal pressure experienced by the internal
surface of a cylindrical tank is expressed in terms of the stresses
in the longitudinal axis of the cylinder and the stresses in the
tangential directions (perpendicular to the longitudinal axis). The
following equations, known as Kessel's equations, express the two
types of stresses (axial stress or .sigma..sub.a and tangential
stress or .sigma..sub.t) in terms of p (measurable pressure), D
(diameter of cylinder) and s (thickness of the tank walls):
.sigma. a = p D 4 s ( 1 ) .sigma. t = p D 2 s ( 2 )
##EQU00001##
[0007] As can be clearly seen from the above equations, the
stresses experienced by the internal surface of the cylinder in the
axial and tangential directions are directly proportional to the
inner diameter of the cylinder. Thus, for relatively large
cylinders such as the 200-350 bar cylinders, there is increased
stress due to the relatively large diameters, D. Because of the
resulting higher stresses that occur, relatively strong fibers are
needed to construct these tanks The cylindrical tanks are typically
constructed using a relatively thin walled metallic cylinder
reinforced with relatively strong fibers wound on the surface of
the cylinder to which some type of polymer has been applied. Thus,
the wound fibers are embedded in the polymer applied to the surface
of the cylinder to form a FRP (Fiber Reinforced Polymer), which
when cured serves as a strong shell adhered to the outer surface of
the metallic cylinder so as to assist the inner metallic surface of
the cylinder to withstand the resulting stresses as defined by
equations (1) and (2) above.
[0008] The fibers used to construct the tanks are usually
relatively strong fibers (such as carbon fibers), which have the
requisite amount of tensile strength and stiffness to withstand the
stresses resulting from relatively large diameter dimensions of the
tanks The issue with these relatively strong fibers is their cost.
Such fibers although used in many industrial and commercial
products are not made in the quantity necessary to provide the
benefits of the economies of scale typically provided by parts
manufactured en masse in relatively high quantities. Carbon fibers
and other fibers with comparable physical characteristics are
relatively very expensive and thus the costs of manufacture of
conventional hydrogen tanks are accordingly expensive.
[0009] Further, as previously stated, the 200-350 bar tanks do not
have an energy capacity comparable to gasoline tanks Therefore, in
order to increase the energy content of these tanks, the amount of
hydrogen per unit volume is increased thus increasing the mass of
hydrogen per unit volume and thus the energy content of the tank;
this is done by increasing the internal pressure at which the
Hydrogen is stored within the tank. For example, tanks having an
internal pressure of 700 bars can be used. Such tanks will
necessarily have more stress applied to their inner walls because
of the increased pressure (See equations 1 and 2 above). With
increasing pressure comes the need for strong fibers, which as
described above makes the costs of such tanks relatively
expensive.
[0010] A review of equations 1 and 2 above shows that one approach
at reducing the stress on the inner walls of the 700 bar tanks, is
to design tanks with thicker inner walls--that is, increasing s
reduces .sigma.. However, a tank with thicker inner walls will
weigh more than the same tank with thinner inner walls. For storage
tanks used in vehicles, the weight of the tank is clearly an
important factor in the overall fuel efficiency of the vehicle.
Also, in many cases the cost of manufacturing such thicker wall
tanks increases due to the extra cost of additional wall material
and modification in the manufacturing process for these tanks.
BRIEF SUMMARY OF THE INVENTION
[0011] The present invention provides a Hydrogen storage system
comprising N storage elements coupled to each other to form one or
more containers that occupy or fit within boundaries of a defined
space with boundaries, dimensions, and shape resulting in a volume
V where N is an integer equal to 2 or greater. Each of the storage
elements has a volume that is a fraction of (or substantially less
than) the volume V resulting in each storage element and the one or
more containers having reduced dimensions compared to the
dimensions of the defined space of volume V. A fraction of the
volume V refers to a volume of space occupied by one of N storage
elements such that all N storage elements fit within the boundaries
of the defined space of volume V. Because each of the storage
elements has a volume that is substantially less than the overall
volume V, the inner surfaces of each of the storage elements
experience substantially less stress compared to the stress
experienced by inner surfaces of one storage tank of volume V. That
is, the volume of each of the storage elements is reduced to a
value that allows usage of less costly but adequately strong fibers
in the construction of such storage elements. As a result, the
reduced stress experienced by the inner surfaces of each of the
storage elements allows the usage of fiber material (e.g., Innegra,
Basalt or other fiber having similar such properties) having
relatively lower tensile strength and stiffness in the construction
of each such storage element thus reducing the cost of the storage
system.
[0012] The respective volumes of each of the storage elements are
not necessarily equal to each other. For a system having N storage
elements, each storage element has a volume defined by dimensions
and shape that may be the same or different from the other storage
elements. When all of the storage elements are coupled to each
other to form one or more containers, the one or more containers
have architectures defined by their shape and size and dimensions.
All of the storage elements when coupled together fit in the
defined space of Volume V either by conforming substantially to the
shape and dimensions of the defined space or by being able to be
disposed totally within the defined space of certain dimensions,
boundaries and shape resulting in a volume V. The terms
"conforming" or "conform" refer to the one or more containers
forming a defined space that has substantially the same shape,
dimensions, boundaries and volume, V of the defined space.
[0013] Each of the storage elements has an inner layer made of a
Hydrogen impermeable material and an outer layer adhered to the
outer surface of the inner layer. The outer layer may be a
composite material made by first applying a resin (e.g., an epoxy
resin) onto the outer surface of the inner layer and then winding a
fiber onto the outer surface at a certain angle with respect to a
defined point(s) of reference (e.g., longitudinal axis of a
cylinder) thus embedding the fiber into the resin and allowing the
fiber-resin combination to cure to form a relatively hard shell.
Alternatively, the fiber can be wound first onto the outer surface
of the inner layer and then a resin is applied; the fiber-resin
combination is then allowed to cure to form a relatively hard
shell. Yet further, the fiber material can be first weaved as a
"sock" that is then snugly fit over the outer surface of the
Hydrogen impermeable material. Resin is then applied to the fitted
material and allowed to cure to form a relatively hard shell for
the storage element. The process of slipping on the "sock" and then
adding resin to the sock can be repeated as many times as desired.
The "sock" refers to fibers weaved into the shape of a storage
element so that a snug fit (i.e., a `glove` fit) can be achieved
when the "sock" is slipped on or over the outer surface of the
storage element made from a Hydrogen impermeable material.
Preferably, the Hydrogen impermeable material is aluminum or an
aluminum alloy and the fiber is made from Basalt, Innegra, or other
material with properties similar to Basalt or Innegra. Other
Hydrogen impermeable materials and fiber materials that meet design
requirements of the storage system of the present invention may be
used. It will be readily obvious that the storage system of this
embodiment and other embodiments of the present invention are not
limited to the Hydrogen impermeable material and the fiber
materials mentioned above.
[0014] In a first embodiment of the storage system of the present
invention, all of the storage elements may be coupled to each other
to form one or more containers positioned proximate each other
within the boundaries of the defined space of volume V where the
containers may be different in size, shape and architecture or they
may all be the same in size, shape and architecture.
[0015] In a second embodiment of the storage system of the present
invention, the storage elements may be coupled to each other to
form one or more containers each of which is positioned within the
boundaries of the defined space of volume V. Additionally, one or
more other containers--not formed from storage elements--can also
be positioned within the boundaries of the defined space of volume
V. The containers formed from storage elements and containers not
formed from the storage elements all fit within the boundaries of
the defined space of volume V.
[0016] A particular implementation which can be used for the first
and/or second embodiments of the present invention comprises
storage elements having two types of shapes, viz., straight
cylinders and bent cylinders having equal outer diameters (D.sub.0,
where 2*r.sub.0=D.sub.0; r.sub.0 is the outer radius) and inner
diameters (D.sub.i, where 2*r.sub.i=D.sub.i; r.sub.i is the inner
radius); all of the bent cylinders have equal curve radii
(r.sub.c). The curve radius for each of the bent cylinders is equal
to kD.sub.0 (i.e., r.sub.c=kD.sub.0) where k is a real number
greater than zero. Each of the bent and straight cylinders has a
volume that is relatively much less than the volume V of a defined
space within which these storage elements are disposed. The
straight and bent cylinders are coupled to each other to form one
or more serpentine cylindrical containers. Also, with the diameter
having some measurable thickness so that there is an inner diameter
D.sub.i and an outer diameter D.sub.0, the diameter value used in
the Kessel equations is
D = D M = D 0 + d i 2 . ##EQU00002##
D.sub.M is thus the mid-diameter or average diameter.
[0017] For the embodiments discussed above and any other
embodiments falling within the claimed storage system of the
present invention, the dimensions and shapes of the storage
elements and/or containers (made and/or not made from storage
elements) can be varied to construct a storage system in accordance
with arbitrary design requirements. One particular set of design
requirements puts limits on the size, cost and weight of the
storage system. Also, depending on the shape of the defined space,
the design requirements may also dictate the shape of the storage
elements and the shape of containers made or not made from the
storage elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings shown in this application represent various
embodiments of the Hydrogen storage system of the present
invention. The various embodiments are not necessarily drawn to
scale and are shown for illustrative purposes to further facilitate
the description and explanation of Hydrogen storage system of the
present invention. A brief description of the drawings is as
follows:
[0019] FIG. 1 shows a serpentine cylindrical container of the
Hydrogen storage system of the present invention;
[0020] FIG. 2 shows a straight cylinder section of the serpentine
cylindrical container of FIG. 1;
[0021] FIG. 2A shows a cross sectional view of FIG. 2 cut along
line 2A-2A and also shows the tangential and axial stress lines due
to internal pressure from stored Hydrogen;
[0022] FIG. 3 shows a bent cylinder section of the serpentine
cylindrical container of FIG. 1;
[0023] FIG. 4 shows the straight cylinder section of FIG. 2 with a
hardened shell made of a composite material;
[0024] FIG. 5 shows the straight cylinder section of FIG. 2 with a
fiber wound thereon at a particular angle;
[0025] FIG. 5A is a top view of FIG. 5 and shows the angles formed
by lines tangential to the wound fiber and the longitudinal axis of
the straight cylinder section of FIG. 5;
[0026] FIG. 6 depicts a graph that shows the relationships between
different parameters in designing cylinders made from different
fibers, having different diameters, mass and weight, and operated
at different internal pressures;
[0027] FIG. 7 shows a serpentine cylindrical container with certain
dimensions;
[0028] FIG. 8 shows one embodiment of the Hydrogen storage system
of the present invention.
[0029] FIG. 9 shows another embodiment of the Hydrogen storage
system of the present invention where the storage elements are
U-shaped;
[0030] FIG. 9A shows a front view of FIG. 9 depicting the angular
arrangement of the storage elements with respect to each other;
[0031] FIG. 10 shows yet another embodiment of the present
invention where the storage elements are capsule shaped;
[0032] FIG. 11 shows a generalized embodiment of the storage system
of the present invention having a volume of arbitrary shape and
comprising three Sections where each section having three
layers;
[0033] FIG. 12 shows the individual storage elements of one section
of the storage system of FIG. 11;
[0034] FIG. 13 shows an exploded view of the three layers of the
section depicted in FIG. 12 and all of the individual storage
elements of that section; and
[0035] FIG. 13A shows how two adjacently positioned storage
elements of the section depicted in FIG. 12 are coupled to each
other.
DETAILED DESCRIPTION
[0036] The present invention provides a Hydrogen storage system
comprising N storage elements coupled to each other to form one or
more containers that occupy or fit within boundaries of a defined
space with boundaries, dimensions, and shape resulting in a volume
V where N is an integer equal to 2 or greater. Each of the storage
elements has a volume that is a fraction of (or substantially less
than) the volume V resulting in each storage element and the one or
more containers having reduced dimensions compared to the
dimensions of the defined space of volume V. A fraction of the
volume V refers to a volume of space occupied by one of N storage
elements such that all N storage elements fit within the boundaries
of the defined space of volume V. Because each of the storage
elements has a volume that is substantially less than the overall
volume V, the inner surfaces of each of the storage elements
experience substantially less stress compared to the stress
experienced by inner surfaces of one storage tank of volume V. That
is, the volume of each of the storage elements is reduced to a
value that allows usage of less costly but adequately strong fibers
in the construction of such storage elements. As a result, the
reduced stress experienced by the inner surfaces of each of the
storage elements allows the usage of fiber material (e.g., Innegra,
Basalt or other fiber having similar such properties) having
relatively lower tensile strength and stiffness in the construction
of each such storage element thus reducing the cost of the storage
system.
[0037] The respective volumes of each of the storage elements are
not necessarily equal to each other. For a system having N storage
elements, each storage element has a volume defined by dimensions
and shape that may be the same or different from the other storage
elements. When all of the storage elements are coupled to each
other to form one or more containers, the one or more containers
have architectures defined by their shape and size and dimensions.
All of the storage elements when coupled together fit in the
defined space of Volume V either by conforming to substantially the
shape and dimensions of the defined space or by being able to be
disposed totally within the defined space of certain dimensions,
boundaries and shape resulting in a volume V. The terms
"conforming" or "conform" refer to the one or more containers
forming a defined space that has substantially the same shape,
dimensions, boundaries and volume, V of the defined space.
[0038] Each of the storage elements has an inner layer made of a
Hydrogen impermeable material and an outer layer adhered to the
outer surface of the inner layer. The outer layer may be a
composite material made by first applying a resin (e.g., an epoxy
resin) onto the outer surface of the inner layer and then winding a
fiber onto the outer surface at a certain angle with respect to a
defined point(s) of reference (e.g., longitudinal axis of a
cylinder) thus embedding the fiber into the resin and allowing the
fiber-resin combination to cure to form a relatively hard shell.
Alternatively, the fiber can be wound first onto the outer surface
of the inner layer and then a resin is applied; the fiber-resin
combination is then allowed to cure to form a relatively hard
shell. Yet further, the fiber material can be first weaved as a
"sock" that is then snugly fit over the outer surface of the
Hydrogen impermeable material. Resin is then applied to the fitted
material and allowed to cure to form a relatively hard shell for
the storage element. The process of slipping on the "sock" and then
adding resin to the sock can be repeated as many times as desired.
The "sock" refers to fibers weaved into the shape of a storage
element so that a snug fit (i.e., a `glove` fit) can be achieved
when the "sock" is slipped on or over the outer surface of the
storage element made from a Hydrogen impermeable material.
Preferably, the Hydrogen impermeable material is aluminum or an
aluminum alloy and the fiber is made from Basalt, Innegra, or other
material with properties similar to Basalt or Innegra. Other
Hydrogen impermeable materials and fiber materials that meet design
requirements of the storage system of the present invention may be
used. It will be readily obvious that the storage system of this
embodiment and other embodiments of the present invention are not
limited to the Hydrogen impermeable material and the fiber
materials mentioned above.
[0039] In a first embodiment of the storage system of the present
invention, all of the storage elements may be coupled to each other
to form one or more containers positioned proximate each other
within the boundaries of the defined space of volume V where the
containers may be different in size, shape and architecture or they
may all be the same in size, shape and architecture.
[0040] In a second embodiment of the storage system of the present
invention, the storage elements may be coupled to each other to
form one or more containers each of which is positioned within the
boundaries of the defined space of volume V. Additionally, one or
more other containers--not formed from storage elements--can also
be positioned within the boundaries of the defined space of volume
V. The containers formed from storage elements and containers not
formed from the storage elements all fit within the boundaries of
the defined space of volume V.
[0041] A particular implementation which can be used for the first
and/or second embodiments of the present invention comprises
storage elements having two types of shapes, viz., straight
cylinders and bent cylinders having equal outer diameters (D.sub.0,
where 2*r.sub.0=D.sub.0; r.sub.0 is the outer radius) and inner
diameters (D.sub.i, where 2*r.sub.i=D.sub.i; r.sub.i is the inner
radius); all of the bent cylinders have equal curve radii
(r.sub.c). The curve radius for each of the bent cylinders is equal
to kD.sub.0 (i.e., r.sub.c=kD.sub.0) where k is a real number
greater than zero. Each of the bent and straight cylinders has a
volume that is relatively much less than the volume V of a defined
space within which these storage elements are disposed. The
straight and bent cylinders are coupled to each other to form one
or more serpentine cylindrical containers. Also, with the diameter
having some measurable thickness so that there is an inner diameter
D.sub.i and an outer diameter D.sub.0, the diameter value used in
the Kessel equations is
D = D M = D 0 + D i 2 . ##EQU00003##
D.sub.M is thus the mid-diameter or average diameter.
[0042] For the embodiments discussed above and any other
embodiments falling within the claimed storage system of the
present invention, the dimensions and shapes of the storage
elements and/or containers (made and/or not made from storage
elements) can be varied to construct a storage system in accordance
with arbitrary design requirements. One particular set of design
requirements puts limits on the size, cost and weight of the
storage system. Also, depending on the shape of the defined space,
the design requirements may also dictate the shape of the storage
elements and the shape of containers made or not made from the
storage elements.
[0043] Referring to FIG. 1, there is shown a particular
implementation of an embodiment of the present invention wherein a
serpentine cylindrical container designed to fit within the base
area 12 (with corresponding volume V) of the trunk of a 2007
Mitsubishi Evo 9, which is a bi-fuel vehicle able to operate on
gasoline and/or Hydrogen. The serpentine cylindrical container
design is described in the context of a trunk of a Mitsubishi Evo 9
for illustrative purposes only. It will be readily obvious that
such an embodiment is not limited to the space defined by the trunk
of the Evo 9 vehicle. It is clear that this embodiment and its
variations can be used in different types of spaces within
automobiles, or storage spaces of different environments. The
boundaries of the base area of the trunk are clearly shown. In
addition to the boundaries shown for the base area of the trunk are
boundaries that delineate and define the volume of the trunk
discussed infra. Accordingly, for ease of explanation, this
embodiment of the Hydrogen storage system of the present invention
will be described in the context of the trunk space of the
Mitsubishi Evo 9 vehicle. The design requirements are that a
Hydrogen storage system capable of storing 3 kg of Hydrogen is to
be located in the trunk of the Mitsubishi Evo 9. The storage system
weight, cost and size are to be as low as possible.
[0044] Continuing with the description of FIG. 1, the serpentine
cylindrical container of FIG. 1 comprises six (6) long straight
cylinder sections (36, 38, 40, 42, 44, 46), four (4) short straight
cylinder sections (32, 34, 48, 50) and nine (9) bent cylinder
sections (14, 16, 18, 20, 22, 24, 26, 28, 30). The various long,
short and bent cylinder sections are arranged as shown in FIG. 1 to
form serpentine cylindrical container 10 that fits within the
spatial boundaries of the trunk of the Mitsubishi Evo 9. The inner
diameter D.sub.i of each of the cylinders (long, short or bent) is
36 mm. Each of the long cylinders is 736 mm in length and the short
cylinders are 336 mm long. Each of the bent cylinders has an arc
length of 113.1mm and a curve radius (r.sub.c) of 76mm and they are
bent to form substantially circular arcs. The curve radius is
defined with respect to the longitudinal axis 220 as mentioned in
the description of FIG. 3. The serpentine storage system of FIG. 1
thus comprises three types of storage elements, viz., short
cylinders, long cylinders and bent cylinders. The thickness, s, of
the cylinders is 1 mm for this embodiment and other embodiments
discussed herein in which aluminum is used to construct the
cylinders or storage elements.
[0045] Referring to FIG. 2, there is shown a perspective view of a
straight (long or short) cylinder section 200 with longitudinal
axis 220 having an inner radius r.sub.i (with corresponding inner
diameter D.sub.i=2r.sub.i) and an outer radius r.sub.0 (with
corresponding outer diameter D.sub.0=2r.sub.0). Cylinder section
200 has a thickness 240 of the Hydrogen impermeable material (e.g.,
aluminum) with which it is made. The geometry of cylinder 200 is
the same or similar to the geometry of the long and short cylinders
of FIG. 1. The cylinder 200 is formed through well-known extrusion
processes or other well known cylinder forming or tube forming
processes.
[0046] FIG. 2A shows FIG. 2 cut along lines 2A-2A of FIG. 2 to
illustrate the direction of the axial stress .sigma..sub.a and
tangential stress .sigma..sub.t forces acting on the inner surface
of cylinder section 200 due to the internal pressure of stored
Hydrogen gas. FIG. 3 shows a bent cylinder storage element 300
having the same inner radius (r.sub.i), outer radius (r.sub.0) and
thickness 240 as the straight cylinder storage elements such as
cylinder section 200. Bent cylinder storage element 300 has a curve
radius r.sub.c; the curve radius is defined with respect to the
longitudinal axis 220 as shown. The curve radius, r.sub.c, is equal
to kD.sub.0 where k is a real number greater than zero; for this
embodiment k=2; this relationship defines the degree of bending
that can be performed on a cylinder. The value of k=2 is currently
the state of the art in aluminum bending technology. The geometry
of bent cylinder storage element 300 is the same or similar to the
geometry of the bent cylinder storage elements of FIG. 1. Each of
the storage elements (bent and straight sections) of the serpentine
container is preferably an extruded aluminum section that can be
made from Aluminum alloy 6xxx (for example Aluminum 6061), which
has a certain strength, thickness and density.
[0047] The storage elements of short, long and bent cylinders
depicted in FIGS. 2, 2A and 3 all have circular cross-section as
they are clearly cylindrical in shape and geometry. It will be
readily obvious to one skilled in this art that the present
invention may also comprise storage elements of the claimed storage
system having cross section profiles that are rectangular,
elliptical, diamond shaped and various other cross sections that
are not circular.
[0048] The volume V of the available trunk space of the 2009
Mitsubishi Evo 9 is 430 dm.sup.3. The formula for the volume of a
cylinder (bent or straight) of length L, diameter D.sub.M (where
D.sub.M=2r.sub.M;
r M = r 0 + r i 2 ##EQU00004##
and thickness s has a volume V.sub.cyl=.pi.r.sub.M.sup.2L or
D M 2 4 L . ##EQU00005##
The inner surface of a cylinder experiences stress from the
pressure, p, of the stored Hydrogen in accordance with the axial
and tangential stress equations (1) and (2) above which are hereby
reproduced below for ease of reference:
.sigma. a = p D 4 s ( 1 ) .sigma. t = p D 2 s ( 2 )
##EQU00006##
[0049] Using the dimensions of the cylinders and the formula for
the volume of a cylinder, the volume for each of the long cylinders
is 0.75 dm.sup.3. The volume for each of the short cylinders is
0.34 dm.sup.3 and for each of the bent cylinders is 0.75 dm.sup.3.
It is clear that the volume of the storage elements (i.e., long
cylinders, short cylinders, and bent cylinders) are much smaller
than the volume V of the defined space, viz., the volume of the
trunk of the 2009 Mitsubishi Evo 9.
[0050] Each of the cylinder storage elements has a hardened shell
adhered to its outer surface. The shell is made of a composite
material, which includes fibers preferably made from Basalt
(C.sup.2 fiber) or Innegra. One implementation of a cylinder
storage element with a hardened shell is depicted in FIG. 4 where
cylinder section 200 (made from aluminum) with thickness 240 has a
hardened outer shell 280 (i.e., fiber--epoxy resin composite
material allowed to cure) of thickness 260 adhered thereon. It
should be noted that the thicknesses 240 and 260 of the inner
cylinder section 200 and outer shell 280 respectively are not
necessarily drawn to scale. The thicknesses may be equal to each
other or either thickness may be greater or less than the
other.
[0051] To form the hardened outer shell or outer layer for the bent
and/or straight cylinder sections, an epoxy resin is first applied
to the outer surfaces of the extruded aluminum sections; the resin
has a certain tensile strength, stiffness and density. A fiber is
then wound (at a certain angle with respect to the longitudinal
axis of the bent or straight cylinder) onto the outer surface at a
certain angle (preferably 54.7.degree.) with respect to the
longitudinal axis 220 (or some other point of reference) of the
cylinder. Alternatively, a fiber is first wound (at a certain
angle--preferably 54.7.degree.--with respect to the longitudinal
axis of the bent or straight cylinders) and then the epoxy resin is
applied to the outer surfaces of the extruded aluminum sections.
The fibers are interwoven with each other creating a thickness of
fibers.
[0052] Referring to FIG. 5, there is shown cylinder section 200
with longitudinal axis 220 and with fiber 232 wound in the
direction shown by curved arrow 222. The angle at which the
fiber(s) is/are wound is obtained as follows. A portion of
longitudinal axis 220 is projected onto the surface of cylinder
section 200 resulting in a line 226 defined by at least two points
A and B located at the two respective ends of cylinder section 200.
Line 226 is the shortest distance between two aligned points at
each end of the cylinder sections and thus, line 226 spans exactly
the length of cylinder section 200. Therefore line 226 is parallel
to and aligned with longitudinal axis 220. It will be readily
obvious that line 226 intersects the wound fiber 232 at multiple
points, some of which are indicated as intersection points 230. At
intersecting points 230 tangential lines 228 are shown which
represent lines drawn tangentially to the intersection points in
the direction of winding (as shown by the arrows of lines 228) at
those points. Each of the resulting tangential lines thus forms an
angle with longitudinal axis 220.
[0053] FIG. 5A shows a top view of FIG. 5 and fiber 232 is not
shown for ease of explanation. The tangential lines 228 in relation
to longitudinal axis 220 and line 226 show the angle--labeled
.alpha.--formed between the tangential lines 228 and longitudinal
axis 220. FIG. 5 shows only one fiber 232 wound around cylinder
section 200 for ease of explanation and clarity of illustration
only. It will be readily understood that a plurality of fibers can
be wound around cylinder section 200 to form composite material
(i.e., hardened shell) 280 having a certain thickness 260 as shown
in FIG. 4. As previously stated, for the serpentine cylindrical
container of FIG. 1, the angle .alpha. is preferably
54.7.degree..
[0054] Another method that can be used to form the hardened outer
shell is to use a fiber tubing process. In this process the fiber
is first weaved onto a mandrel to follow the shape and dimensions
of the mandrel forming a tube or "sock" or a weaved fiber having
the shape of the storage element for which a hardened shell is
being constructed. The mandrel has the same shape and dimensions as
the storage element. The sock (or weaved fiber shape) is then
frictionally and/or snugly fit over the outer surface of the
storage element. Resin is then added to the fiber. The process can
then be repeated with additional layers of fiber (with the proper
adjustments made for the dimensions of the weaved fiber sock or
weaved fiber shape) and resin as needed or desired. The layers of
fibers and resin are then allowed to cure to form the hardened
shell.
[0055] A fiber primarily made from volcanic rock such as Basalt
rock is preferably used in the storage system of the present
invention. For example, a Basalt fiber referred to as C.sup.2 fiber
having a mineralogical composition comprises at least is 52%
SiO.sub.2, 17% Al.sub.2O.sub.3, 9%CaO, 5% MgO and 17% of various
other substances typically found in volcanic rock. Depending on the
mechanical and chemical properties of the fibers that are
desirable, various adjustments can be made to the composition. The
fiber can also be an Innegra fiber. By using storage elements with
reduced dimensions, the need for relatively very strong and
expensive fibers is eliminated. Thus, fibers not as strong as the
strongest fibers (e.g., carbon, steel or silicon carbide), which
have acceptable mechanical and chemical properties (such as the
properties of Basalt and Innegra) and are relatively inexpensive
become excellent candidates for the construction of the storage
elements and containers used in the storage system of the present
invention. A comparative look at some representative fibers and
their relative properties is shown in the table below:
TABLE-US-00001 Tensile Specific Density Stiffness Strength
Elongation Strength Strength Price [Kg/dm.sup.3] [N/mm.sup.2]
[N/mm.sup.2] [%] per density per costs [ /kg] Innegra 0.84 18,000
590 5 702 176 4 DP1000-steel 7.83 210,000 1000 10 128 18 7 Dyneema
0.97 100,000 3200 3.4 3300 43 77 Vectran 1.4 103,000 3000 3.3 2143
48 45 Glass 2.7 80,000 1800 3.5 667 56 12 Basalt 2.7 100,000 2150 4
796 159 5 Silicon Carbide 2.5 420,000 3400 0.05 1360 27 50 Carbon
1.8 400,000 4500 1 2500 125 20 Aramid 1.5 130,000 3500 2.8 2333 117
20
[0056] The strongest fibers listed in the table above are those
with the highest stiffness and tensile strength, viz., Dyneema,
Silicon carbide, and Carbon. These fibers also have some of the
highest specific strengths (or strength per density) in the table.
The strength per density is the ratio of tensile strength to
density, which is highest for Carbon and Dyneema. However when the
strength of a fiber is related to its cost, the Basalt and Innegra
fibers yield the highest value for the fibers in the table
(specific strength per cost for Basalt is 159 and Innegra 176);
this is because Basalt and Innegra are the least expensive fibers
per unit weight (4 Euros per Kg for Innegra and 5 Euros per Kg for
Basalt) of any of the fibers in the table. Therefore, Basalt,
Innegra and other fibers with similar strength per cost values
become excellent candidates for the storage system of the present
invention because the sizes of the storage elements relative to
conventional Hydrogen tanks allow the use of fibers that are not as
strong as Carbon or Silicon carbide.
[0057] Various parameters related to the materials used to
construct the storage elements and/or containers and the geometries
of the containers and storage elements have a direct impact on the
design of the storage system of the present invention. As discussed
above, the three main considerations for the Hydrogen storage
system of the present invention are its weight, size and cost. Some
of the parameters that directly impact the weight, size and cost of
the storage system of the present invention include choice of fiber
material, thickness of the aluminum cylinders (or thickness of
Hydrogen impermeable material), fiber fraction, (i.e., the ratio of
amount of fiber to the amount of composite material made from fiber
and epoxy resin) fiber angular positioning on the inner layer, the
pressure at which the Hydrogen is stored and the dimension (in this
case, the diameter of the cylinders) of the storage elements.
[0058] To design the storage elements and containers, one approach
is to vary a dimension (say for example diameter, D) of a storage
element. Through this approach, the varying parameter will
determine the value of the parameters that are related to the size,
weight and cost of the storage elements. For example, varying one
key parameter such as increasing the diameter of the storage
elements will decrease the weight of the storage element per
Hydrogen unit and increase the mass of the Hydrogen that can be
stored. This is because the increase in D increases the volume in a
square relationship and increases the stresses in a linear
relationship. For example, if D is doubled, the stresses increase
by a factor of 2, but the volume increases by a factor of 2.sup.2
or 4. Thus, the volume increases much more than the stresses for
the same increase in D; keeping the amount of Hydrogen constant
while increasing D results in a decrease of the weight per Hydrogen
of the storage system. Clearly, however, the amount of Hydrogen
that can be stored increases as D is increased. An increase in D
will increase the stresses accordingly as already discussed and
thus the fiber needed to withstand the resulting stress may be more
expensive than what is called for by the design requirements. FIG.
6 is a chart showing the interrelationships between the diameter of
cylinder storage elements, the mass of the cylinders (thus their
weight) and the mass of the stored Hydrogen.
[0059] Referring to FIG. 7, there is shown the maximum length of a
serpentine cylindrical container that can fit within the footprint
(and also within the volume) of the trunk of the 2007 Mitsubishi
Evo 9. The maximum length is obtained by decreasing the diameter of
the cylindrical storage elements. Complying with the requirement
that the curve radius is equal to twice the diameter
(r.sub.c=kD.sub.0=2r.sub.0), decreasing the diameter decreases the
curve radius thus allowing more long and short sections to be
coupled to each other in the space provided which serves to
increase the overall length of the serpentine cylindrical
container. For a diameter of 10 mm, the container shown in FIG. 7
has eight (8) short cylinders (each 432 mm in length), 18 long
cylinders (each 832 mm in length) and twenty-five (25) curved
cylinders (each having a curve radius of 76 mm and a length of 75.4
mm). For cylinders having diameters of 5mm or less, no hardened
outer shell is used. Generally, for storage elements in which the
volume of such an element is relatively small, no outer shell is
used.
[0060] A modified version of the already discussed design approach
for the storage system of the present invention is to define ranges
for an acceptable minimal mass of Hydrogen and a maximum weight of
the storage system. The diameter of the storage elements can then
be calculated or determined to meet these design requirements. It
is easily seen that the value of the diameter will determine the
weight of the storage system, the size of the storage system.
Further, the diameter value will determine the stress and thus the
choice of fiber for the storage elements, which is a significant
factor in the overall cost of the storage system.
[0061] Referring now to FIG. 8, there is shown an embodiment in
which one container is made from the coupling of storage elements
(i.e., straight cylinders and bent cylinders) to each other to form
a serpentine cylindrical container 600 and the other two containers
602, 604 are spherical containers not formed from storage elements.
The three containers are positioned proximate each other and are
disposed within the boundaries a space 606 of volume V=430 dm.sup.3
defined by the boundaries of the trunk of the 2007 Mitsubishi Evo
9.
[0062] The storage elements are not necessarily limited to
cylinders or elements having circular profiles. Storage elements
having rectangular, square, triangular, elliptical, arbitrarily
configured profiles and other profiles can be considered as tubes
(of various lengths) which can be coupled to each other to form
containers that conform to the particular shape and contours of a
defined space (with defined boundaries) having a volume V and which
fit within the boundaries of the defined space. These tubes may be
bent or shaped in various ways so that they fit within a particular
defined space delineated by boundaries.
[0063] Referring now to FIG. 9, there is shown another embodiment
700 of the storage system of the present invention where each of
the storage elements is a U-shaped element 702 that is constructed
using a bent cylinder section as in FIG. 3 and two short cylinder
sections (similar to FIG. 4) or constructed with an integral
one-piece U-shaped section. Whether constructed as a one piece
storage element or a three piece storage element, the cylindrical
sections are manufactured in the same or similar fashion (and made
with the same materials) as the cylindrical sections described with
respect to FIGS. 2-5A. Each of the U-shaped storage elements 702
has the same shape and dimensions. However, one can easily conceive
a storage system where all of the storage elements are U-shaped but
some or all are of different sizes. Each of the U-shaped storage
elements 702 is connected to a common distribution conduit 704
(which may be a cylinder or a pipe or other shape), which serves as
a coupling member to all of the U-shaped storage elements 702.
Thus, all of the storage elements are coupled to each other via
this common conduit. Another conduit 706 is coupled to the
distribution conduit 704 as shown. Conduit 706 (similar to conduit
704) can be made and/or manufactured with the same materials and in
the same or similar fashion as the storage elements described with
respect to FIGS. 2-5A. Conduits 704 and 706 can also be made from
any appropriate Hydrogen impervious material; preferably conduits
704 and 706 can be made from stainless steel or the hydrogen
impervious material and composite material shell described with
respect to the serpentine containers discussed above. The conduits
704 and 706 may be coupled to each other via a threaded T-connector
or other well known threaded connector.
[0064] FIG. 9A shows a front view of the storage system of FIG. 9
positioned on or adhered to a flat surface 705. Each of the storage
elements 702 defines a plane 703 with its U-shape geometry. Thus,
each of the storage elements forms an angle .theta. defined by
plane 703 and surface 705. The particular value of .theta. will
depend on any number of factors including volume V within which the
resulting container (comprising a plurality of U-shaped containers
coupled to each other via conduit 704) is disposed.
[0065] The embodiment shown in FIGS. 9 and 9A is an example of what
is referred to as a "straight pipe" design where each of the
storage elements is coupled to a common conduit (e.g., a pipe)
through which Hydrogen gas is delivered to the various storage
elements. Such an arrangement or configuration is relatively more
conducive to automated manufacturing and assembly. In particular,
each of the storage elements and the common conduit can be made
from material similar to the storage elements used in the
serpentine containers discussed above. Further, the assembly of the
individual storage elements to the common conduit can also be
achieved in an automated fashion making the manufacture of such
straight pipe designs more efficient and thus relatively less
costly than other types of designs. Also, the "straight pipe"
design is a modular design approach because one set of storage
elements coupled to a common conduit can be coupled to another
similar set. For example, for a given space of volume V, the
embodiment shown in FIG. 9 can be replicated K times (K is an
integer equal to 2 or greater) and each of the K straight pipe
designs can be coupled to another similarly configured straight
pipe design forming a modularized embodiment of the storage system
of the present invention. Further, different types of "straight
pipe" designs can be coupled to each other to form yet another type
of modularized embodiment of the storage system of the present
invention.
[0066] FIG. 10 shows another straight pipe embodiment of the
storage system of the present invention where the storage elements
802 are shaped as capsules and are coupled to a conduit 804 via
straight connectors 810. In the example depicted by FIG. 10, there
are 16 capsule storage elements. It will be readily understood that
the storage system may contain any number of capsules as necessary
to meet a particular design requirement. At the ends of the conduit
804, the storage elements are coupled to conduit 804 via
right-angled connectors 808. Each of the storage elements is shaped
as a capsule; that is, each element is cylindrical in form, but the
ends of the cylinder are semi-spherical in shape. Another conduit
812 is coupled to conduit 804 with the use of a T-connector 806 as
shown. Conduit 804, straight connector 810, right angle connector
808 and T-connector 806 can all be made from stainless steel or
other appropriate Hydrogen impermeable material; these parts can
also be made from the same materials used to construct the
serpentine containers discussed above.
[0067] The storage system shown in FIGS. 9 and 10 are referred to
as "straight pipe" systems because each such system has a conduit
(704 in FIGS. 9 and 804 in FIG. 10) to which the storage elements
are coupled. Such an arrangement or configuration of storage
elements is more conducive to automated assembly. Further, storage
systems using the "straight pipe" configuration or arrangement can
be modified more quickly.
[0068] The various embodiments described above all comprise storage
elements that are cylindrical in shape and appropriately sized and
dimensioned such that their relatively small volumes allow the use
of relatively inexpensive materials having relatively lower tensile
strength and stiffness to construct them. The following embodiment
depicts a storage system in which the storage elements are not
cylindrical but are arbitrary in shape and dimension and but they
have relatively small volumes that allow the use of inexpensive
materials in their construction. Thus, for the embodiments
described above and the embodiment to be discussed below (FIGS.
11-13A) Hydrogen of pressure equal to 700 bars or greater can be
stored in such storage systems.
[0069] FIG. 11 shows a storage system 900 of the present invention
having a volume V of arbitrary shape and dimensions divided into N
different storage elements, which when coupled to each other as
shown form the storage system shown in FIG. 11. Arbitrary shape and
dimensions mean any space of volume V, which can be defined by a
particular shape with particular dimensions where such shape and
dimensions are created in arbitrary fashion or are created for any
conceivable purpose. Each of the storage elements has a volume
V i .ltoreq. V N ; ##EQU00007##
with i=2, 3, 4, 5, . . . , N and where each such volume V, is
relatively small (compared to V; i.e., V.sub.i<<V) such that
the materials and techniques used in constructing the storage
elements described with respect to FIGS. 1-5A can also be used to
construct these storage elements. That is, the storage system of
FIG. 11 comprises N storage elements (N is an integer equal to 2 or
greater) each having a volume V.sub.i which allows the use of a
Hydrogen impermeable material (such as Aluminum) with a fiber-resin
shell where the fiber can be made from such materials as Innegra,
Basalt or materials with properties similar to those of Innegra and
Basalt. When these storage elements are coupled together as shown,
they form the storage system of the present invention, viz., a
container having a particular shape and volume. The winding of the
fiber process or the fiber tubing process described above with
respect to the construction of the hardened outer shell for
cylindrical storage elements can be used to construct the fiber
hardened outer shells of the storage elements for the storage
system of FIG. 11.
[0070] The particular embodiment shown in FIG. 11 has a shape that
conforms to the shape of the volume V within which this storage
system is disposed; that is, the storage system of the present
invention has substantially the same or similar shape and has
substantially the same dimensions as the available space of volume
V so that the storage system can fit within the defined space or
the storage system defines a space that is similar to or is exactly
the shape and dimensions of the defined space. Because this
embodiment of the storage system of the present invention conforms
to the shape of the volume within which it occupies, an efficient
use of the volume space can be achieved. The various storage
elements are shaped and dimensioned such that when they are all
coupled to each other and positioned as shown, the resulting
storage system conforms to the shape of the available volume V.
Thus, such an embodiment can be used to replace previous tanks
having arbitrary shapes that were used to contain other fuels such
as natural gas, gasoline, liquid fuels and/or other matter.
Further, the same space can now be used to store Hydrogen at
relatively high pressures (e.g., 700 bars or higher) for various
applications such as a vehicle storage system, storage system for
generating electricity, storage system for home heating, storage
system for industrial applications, storage systems used to
transport Hydrogen and other types of storage systems. This
particular embodiment of the storage system of the present
invention can take on the exact shape or a similar shape of the
tanks used to store these various fuels. The storage system shown
in FIG. 11 can be described as having three layers L.sub.1,
L.sub.2, and L.sub.3 and three sections S.sub.1, S.sub.2 and
S.sub.3 as shown. Thus, the storage elements are coupled to each
other to form a container comprising one or more sections.
[0071] Referring now to FIG. 12, the storage system of FIG. 11 is
shown with a detailed depiction of section S.sub.1. As with the
other sections, Section S.sub.1 comprises three layers 902, 904 and
906, which are portions of layers L.sub.1, L.sub.2, and L.sub.3
respectively. As shown for this specific storage system, each of
the layers (902, 904 or 906) comprises seven (7) storage elements
coupled together via openings in the same or similar manner as the
storage elements of the serpentine storage elements discussed
above. Layer 902 of section S.sub.1 comprises storage elements
902A, 902B, 902C, 902D, 902E, 902F and 902G. Layer 904 of section
S.sub.1 comprises storage elements 904A, 904B, 904C, 904D, 904E,
904F and 904G. Layer 906 of section S.sub.1 comprises storage
elements 906A, 906B, 906C, 906D, 906E, 906F and 906G.
[0072] Referring now to FIG. 13, an exploded perspective view of
section S.sub.1 is shown. More particularly, FIG. 13 illustrates
how each of the layers forms a portion of section S.sub.1.
Referring temporarily to FIG. 13A, there is shown how storage
element 902A is coupled to 902B via openings 903A and 903B. The
openings at which the storage elements 902A and 902B are coupled
can be tapered in complementary fashion (not shown) to promote
coupling. Another embodiment of this storage system may have a
circular opening (not shown) at the side where openings 903A and
903B are located and a cylindrical tube can then be used to couple
the two storage elements 902A and 902B together. Various other
methods and techniques can be used to properly couple the storage
elements to each other. The methods and techniques shown and
discussed do not at all represent the entire set of techniques and
methods that can be used to couple the storage elements of the
storage system of the present invention to each other. It should be
noted that sections of storage elements or individual storage
elements are said to be "coupled" to each other when their openings
align with each other to define a container for Hydrogen with
virtually no leakage. However, storage elements which are attached
to each other or which are positioned in relatively close proximity
to each other mean storage elements that are placed physically
sufficiently close to each other but are not necessarily "coupled"
to each other.
[0073] Referring back to FIG. 13, each of the storage elements of
each layer has at least one opening to allow the coupling of each
such storage element to adjacently positioned storage elements of
that layer. It will be clear from a review of FIGS. 12 and 13 that
except for storage element 902A, each of the storage elements
902B-902G has two openings. Further, storage element 902G couples
to storage elements of different layers and is thus a layer
coupling storage element as its opening 1000A aligns with an
opening 1000B of storage element 904G of layer 904. Layer 904
comprises storage elements 904A-904G. Similar to layer 902, each of
the storage elements of layer 904 has two openings. Storage element
904A, however, is also a layer coupling storage element as its
opening 2000A is aligned with opening 2000B of storage element 906A
of layer 906. Layer 906 comprises storage elements 906A-906G. When
the three layers 902, 904 and 906 are coupled to each other via the
layer coupling storage elements as discussed, they define a space
or section S.sub.1. A similar arrangement can be constructed in
sections S.sub.2 and S.sub.3 and all three sections can be coupled
(S.sub.1 to S.sub.2 and S.sub.2 to S.sub.3) to define the overall
space of this embodiment of the storage system of the present
invention. For example, section S.sub.1 can be coupled to section
S.sub.2 via openings (not shown) at particular adjacently
positioned storage elements from sections S.sub.1 and S.sub.2.
Further, section S.sub.2 can then be coupled to section S.sub.3
also via openings (not shown) at particular adjacently positioned
storage elements from these two sections. The three sections can be
coupled as described above and positioned in close proximity to
each other (or attached to each other) to form the storage system
of the present invention as depicted in FIG. 11. Thus a plurality
of the N storage elements are coupled to each other to form one or
more sections each of which is coupled to another section and can
be attached or positioned in relatively close proximity to each
other so that all the sections fit within the space of volume V
having an arbitrary shape and dimensions that conform to the shape
of the embodiment of the storage system of the present invention as
shown in FIG. 11. The coupled sections S.sub.1, S.sub.2, and
S.sub.3, form a container, which conforms to the shape and
dimensions of the defined space of volume V. The coupled sections
may form more than one container all of which when coupled together
may conform to the shape and dimensions of the defined space of
volume V and/or may fit within the boundaries of the defined space
of volume V.
[0074] The storage system of the present invention has been
described in terms of storage elements that are coupled to each
other to form containers within which Hydrogen is stored to power
vehicles. It will be readily obvious however that the Hydrogen
storage system of the present invention can be used for storage
systems for various other applications such as storage systems for
vehicles used to distribute Hydrogen to refill stations. These
vehicles transport large amounts of Hydrogen in large tanks; the
storage system of the present invention can be used to replace
these large tanks The transported Hydrogen is delivered to refill
stations for vehicles and is stored in storage tanks at those
locations. Further the transported Hydrogen can be delivered to
households or places of business, which use the delivered Hydrogen
for heating systems and electricity generating systems. The storage
system of the present invention can thus be used to transport
Hydrogen to distribute the Hydrogen to refill stations. The present
invention can be used to store Hydrogen at the refill stations.
Further, the storage system of the present invention can be used to
store Hydrogen in households or commercial buildings for heating or
for generating electricity. Yet further, containers built in
accordance with the storage system of the present invention and
which are located at power stations can be used to generate
electricity.
[0075] The storage system of the present invention has been
described in terms of the various embodiments disclosed herein. It
will be readily understood that the various embodiments discussed
do not at all limit the scope of the present invention. One of
ordinary skill to which the present invention belongs can, after
reading this specification and the claims, implement the storage
system of the present invention using other embodiments and
implementations that are different from those disclosed herein but
which are well within the scope of the claimed hydrogen storage
system of the present invention.
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