U.S. patent application number 12/616029 was filed with the patent office on 2010-05-13 for hybrid wind turbine.
Invention is credited to Thomas McMaster.
Application Number | 20100117372 12/616029 |
Document ID | / |
Family ID | 39674499 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100117372 |
Kind Code |
A1 |
McMaster; Thomas |
May 13, 2010 |
Hybrid Wind Turbine
Abstract
A thermal energy system comprises a primary thermal energy
system, a solar thermal energy system, a burner, and a heat
recovery system. The solar thermal energy system comprises a pipe
for absorbing heat from solar rays. The burner is arranged such
that the pipe of the solar thermal energy system is capable of
absorbing heat from the burner. The heat recovery system uses
thermal energy from at least one of the primary and solar thermal
energy sources.
Inventors: |
McMaster; Thomas;
(Bellingham, WA) |
Correspondence
Address: |
SCHACHT LAW OFFICE, INC.
SUITE 202, 2801 MERIDIAN STREET
BELLINGHAM
WA
98225-2412
US
|
Family ID: |
39674499 |
Appl. No.: |
12/616029 |
Filed: |
November 10, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12022958 |
Jan 30, 2008 |
7615884 |
|
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12616029 |
|
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|
60898619 |
Jan 30, 2007 |
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Current U.S.
Class: |
290/55 ; 126/609;
60/641.8 |
Current CPC
Class: |
F03D 13/20 20160501;
Y10S 415/908 20130101; F03D 9/00 20130101; Y02E 10/728 20130101;
Y02E 10/46 20130101; F05B 2220/70 20130101; Y02E 10/72
20130101 |
Class at
Publication: |
290/55 ; 126/609;
60/641.8 |
International
Class: |
F03D 9/00 20060101
F03D009/00; F24J 2/42 20060101 F24J002/42; F03G 6/00 20060101
F03G006/00 |
Claims
1. A thermal energy system comprising: a primary thermal energy
system; a solar thermal energy system comprising a pipe for
absorbing heat from solar rays; a burner, where the burner is
arranged such that the pipe of the solar thermal energy system is
capable of absorbing heat from the burner; and a heat recovery
system that uses thermal energy from at least one of the primary
and solar thermal energy sources.
2. A method comprising the steps of: providing a primary thermal
energy system; providing a solar thermal energy system comprising a
pipe for absorbing heat from solar rays; arranging a burner such
that, when the burner generate heats, the pipe of the solar energy
system absorbs heat generated by the burner; and recovering the
thermal energy from at least one of the primary and solar thermal
energy sources.
3. A hybrid wind turbine comprising: blades supported on a hub; a
generator operatively connected to the hub such that rotation of
the blades operates the generator; an engine operatively connected
to the generator such that operation of the motor operates the
generator; a solar thermal energy system; and a heat recovery
system; wherein the heat recovery system uses exhaust heat from the
generator and heat collected by the solar thermal energy system.
Description
RELATED APPLICATIONS
[0001] This application (Attorney Matter No. P216290) is a
continuation in-part of U.S. patent application Ser. No. 12/022,958
filed Jan. 30, 2008, now U.S. Pat. No. 7,615,884 issued Nov. 10,
2009.
[0002] U.S. patent application Ser. No. 12/022,958 claims priority
of U.S. Provisional Application Ser. No. 60/898,619 filed Jan. 30,
2007.
[0003] The contents of all related application listed above are
incorporated herein by reference.
TECHNICAL FIELD
[0004] The present invention relates in general to wind turbine
technology, and more particularly to a system combining the
apparatus and method of the wind turbine with other energy
sources.
BACKGROUND
[0005] While wind turbine power has many advantages as an
additional and/or alternative source of energy, it does have the
drawback that there are time intervals where it is not able to
produce any power at all, or only a small amount of power. Thus,
there have been various approaches to combine the wind power source
with other independent power sources to be able to produce power
more reliably, in the form of "firm power".
[0006] A search of the patent literature has disclosed patents
related to solving these problems, and these are summarized in the
following text.
[0007] U.S. Pat. No. 4,204,126 (Diggs) discloses a "Guided Flow
Wind Power Machine With Tubular Fans", which, when powered by the
wind, can generate electricity. Also, when there is enough wind
power it has the capability of also lifting "massive weights"
hydraulically. Then when the wind has subsided, the weights can be
permitted to be drop downwardly to supply energy to drive a
generator. FIGS. 4 and 5 show the weights 114 through 120 arranged
in quadrants.
[0008] U.S. Pat. No. 5,740,677 (Vestesen) shows a system which is
adapted to for use at a location where there is a need for
electricity and also fresh water. However, this residential
community is also near a source of salt water. There is a wind
diesel plant which supplies electricity for various uses and also
operates a distillation unit to supply the fresh water. The
wind/diesel plant comprises at least an internal combustion engine,
a wind turbine, a distillation unit, a first closed fluid circuit
containing heating and cooling devices, and a second open fluid
circuit.
[0009] U.S. Pat. No. 6,127,739 (Appa) issued Oct. 3, 2000, and is
the first of three patents which have the same inventor. In this
patent, there is a forward front rotor 12 having blades that would
cause rotation in one direction, then there is a rear rotor 21
(called a "leeward rotor 21") positioned behind the front rotor 12
and rotating in the opposite direction. This patent states that the
various items added to this apparatus would produce a substantially
higher "value of energy efficiency factor".
[0010] U.S. Pat. No. 6,278,197 (Appa) is the second patent to the
inventor and it discloses a wind turbine where there is a forward
set of turbine blades which rotate in one direction, and a second
set of turbine blades which are in the wake of the first set and
which rotate in the opposite direction. The reason given for this
is that there is still energy in the air that passes through the
first set of turbine blades, and this is utilized in the second set
of turbine blades.
[0011] U.S. Pat. No. 6,492,743 B1 (Appa) is the third (and more
recent) patent to Mr. Appa, and this also shows a basic
configuration of wind turbine where there are forward and rear sets
of blades. There is a heat exchanger having a centrifugal fan to
circulate ambient air to cool an alternator in the apparatus, and
the hot air is directed to a combustion chamber by means of an air
duct in the blades. Natural gas or liquid is also conveyed to the
rotating frame. When wind speed is low, fuel will be injected into
the combustion chamber and burned with a large mass of air. The hot
gasses expand in an exit nozzle to provide thrust to assist wind
power.
SUMMARY
[0012] The present invention may be embodied as a thermal energy
system comprising a primary thermal energy system, a solar thermal
energy system, a burner, and a heat recovery system. The solar
thermal energy system comprises a pipe for absorbing heat from
solar rays. The burner is arranged such that the pipe of the solar
thermal energy system is capable of absorbing heat from the burner.
The heat recovery system uses thermal energy from at least one of
the primary and solar thermal energy sources.
[0013] The present invention may also be embodied as a method
comprising the following steps. A primary thermal energy system is
provided. A solar thermal energy system comprising a pipe for
absorbing heat from solar rays is provided. A burner is arranged
such that, when the burner generate heats, the pipe of the solar
energy system absorbs heat generated by the burner. Thermal energy
from at least one of the primary and solar thermal energy sources
is recovered.
[0014] The present invention may also be embodied as a hybrid wind
turbine comprising blades supported on a hub, a generator, an
engine, a solar thermal energy system, and a heat recovery system.
The generator is operatively connected to the hub such that
rotation of the blades operates the generator. The engine is
operatively connected to the generator such that operation of the
motor operates the generator. The heat recovery system uses exhaust
heat from the generator and heat collected by the solar thermal
energy system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is an elevation view of a hybrid wind turbine system
of a first embodiment of the present invention;
[0016] FIG. 2 is an isometric exploded view showing the components
of a typical wind turbine apparatus, some or all of which can be
combined with the wind turbine apparatus of the embodiments of the
present invention;
[0017] FIG. 3 is a somewhat schematic view of a power generating
section 16 of the first embodiment;
[0018] FIGS. 4, 4A and 4B are views similar to FIG. 3 showing a
second embodiment illustrating alternate locations for the
auxiliary drives;
[0019] FIGS. 5 and 5A are views similar to FIGS. 1 and 3, showing a
third embodiment which shows a heat recovery section in the support
tower;
[0020] FIG. 6 shows yet a fourth embodiment of the invention, where
a steam generator and steam turbine are utilized as the auxiliary
power source;
[0021] FIGS. 7 and 7A are views that show a basic wind turbine
system which also utilizes solar energy to add energy to the
system;
[0022] FIG. 8 is similar to FIG. 7 in that it shows a basic wind
turbine system which also utilizes an engine auxiliary drive with
heat recovery and an associated steam turbine auxiliary drive;
[0023] FIG. 9 shows a system for a solar thermal energy system
which is independent of the wind turbine power generation system
but occupies the same wind turbine structure;
[0024] FIG. 10 is a combination of FIGS. 7 and 8 in that it shows a
basic wind turbine energy system which utilizes an engine auxiliary
drive with heat recovery, an associated steam turbine auxiliary
drive, and a solar thermal energy system which uses the same steam
turbine;
[0025] FIG. 11 shows a basic wind turbine system with the addition
of the nacelle substructure for housing additional heat recovery
and power generation equipment;
[0026] FIG. 12 is a somewhat schematic, elevation view of a hybrid
wind turbine system of a tenth example of the present
invention;
[0027] FIG. 13 is a somewhat schematic, elevation view of a hybrid
wind turbine system of an eleventh example of the present
invention;
[0028] FIG. 14 is an elevation view of a hybrid wind turbine system
of a twelfth example of the present invention;
[0029] FIG. 15 is a section view of an absorber portion of the
hybrid wind turbine system of FIG. 14;
[0030] FIG. 16 is a longitudinal section view of the absorber
portion of the hybrid wind of FIG. 14;
[0031] FIG. 17 is a schematic drawing of an example heat exchange
system that may be used by the system of FIG. 14; and
[0032] FIG. 18 is a schematic drawing of an example heat exchange
system that may be used by the system of FIG. 14.
DETAILED DESCRIPTION
[0033] It is believed that a clearer understanding of the present
invention can be obtained by first reviewing briefly the overall
system of a first example of the present invention, as shown in
FIG. 1. The discussion of the overall system of the first example
will be followed by a more detailed description of a group of
components shown in FIG. 2, which are typically found in related
wind turbine apparatus, and some or all of which can be
incorporated in one or more of the examples of the present
invention described herein. The discussion of the related wind
turbine components will then be followed by a more detailed
description of a number of examples of systems incorporating the
principles of the present invention.
A. General Description of First Example
[0034] To proceed now with the more general description of the
first example, as indicated above, this will be done with reference
to FIG. 1. There is a wind turbine assembly 10 which comprises a
base support section comprising a vertically aligned tower 11 which
is supported by a base 12. At the upper end of the tower 11, there
is a power generating main support structure 13 which is rotatably
mounted to the tower 11 to rotate about a vertical axis of rotation
14 centrally located in the tower 11. This support section 13
provides a support for a power generating section 16 of the first
example, and it may be in the configuration of a nacelle 13
commonly used with wind turbines.
[0035] The entire power generating section 16 comprises a blade
section 18, a rotary speed changing drive section 20, a generator
section 22, and an auxiliary power section 24. The blade section 18
comprises a plurality of turbine blades 28, and a hub or rotor 30
to which the blades 18 are connected.
[0036] The blade section 18 and the speed changing drive section 20
can be grouped as the primary power generating portion while the
auxiliary power section 24 (as well as the auxiliary power or back
up power components, including those that are shown in other
examples) can be considered as being in a secondary power
generating portion.
[0037] The primary and secondary power generating portions together
function in a manner to enable the generator 22 to provide firm
power.
B. Summary of Related Components
[0038] With the overall description of this first example being
presented, attention is now directed to FIG. 2, which, as indicated
above, is an exploded drawing of a number of components which in
themselves exist in the prior art and are commonly used in present
day wind turbines. In FIG. 2 only two of the three blades 28 are
shown and the rotor 30 is not shown. There is a low speed shaft 32,
which (as shown in FIG. 3) connects to a speed changing drive
section 34 which is shown somewhat schematically, and (as its name
implies) provided a power output at a higher RPM than that of the
shaft 32.
[0039] This drive section 34 is commonly in the form of a gear
section. In general, the rotational speed of the low speed shaft 32
would be between about 30 to 60 rotations per minute, and the gear
section 34 is in turn connected to the generator 22 to cause it to
rotate at a speed between about 1,200 to 3,600 RPM. This would
typically be a rotational speed required by a large number of
present day generators to produce electricity. The gear section 34
connects to a shaft 38 which is located in the generator 22.
[0040] There is provided an anemometer 40 which measures the wind
speed, and also a wind vane 42 to ascertain wind direction. Both
the wind speed and the wind direction data are transmitted to a
controller 44. The controller 44, as its name implies, performs
various control functions. For example, it controls a yaw drive 46
and its associated motor 48 to keep the blade section 18 facing
into the wind as the wind direction changes, starts and stops the
wind turbine, etc. There is also provided a disc brake 49 for the
low speed shaft 32, and in the prior art this can be applied
mechanically, electrically, or hydraulically to stop the rotation
of the rotary components in emergencies.
[0041] All, or most all, of the components which are shown in FIG.
2 are, or may be, present in the examples of the present invention.
However, for convenience of illustration (e.g., to avoid cluttering
up the drawings), these are not shown in the following drawings
(FIGS. 3-11) which illustrate a number of examples of the present
invention.
C. First Example
[0042] All (or many) of the components of this first example are
shown in at least one of FIGS. 1, 2 and 3. Reference is now made to
FIG. 3. It will be noted that a number of the components which
appear in FIG. 3 also appear in either FIG. 1 or 2. For
clarification, those components in FIG. 3 which already appear in
either or both of FIGS. 1 and 2, are given like numerical
designations, with an "a" suffix distinguishing those particular
components. Then the components which appear in FIG. 3 and which do
not appear in either FIG. 1 or 2 will be given new numerical
designations.
[0043] To proceed now with a description of the first example of
FIG. 3, as in FIG. 1, there are the blades 28a which are attached
to the hub 30a. The hub 30a in turn connects to and drives the low
speed shaft 32a. The low speed shaft 32a in turn drives the speed
changing drive section 20a which then provides a high rotational
speed power output to the generator 22a.
[0044] The components of this first example described in the
paragraph immediately above, are already found in FIG. 1 or 2. In
FIG. 3 there is also shown an auxiliary drive section 24a capable
of providing a drive output to the generator 22a.
[0045] For convenience of description, in describing the location
of the components in FIG. 3, the hub 30a shall be considered to be
a front or forward location, and the location of the auxiliary
drive unit 24a shall be considered as having a rear location. Also,
the axis of rotation of the hub 30a, the blades 28a, and also of
the low speed shaft 32a, and any other components which rotate on
the same axis, shall be designated the "power generating axis of
rotation 67".
[0046] To return now to the description of this first example, the
auxiliary drive unit 24a provides a rotating drive output to a
torque converter 66. The torque converter 66 in turn has a drive
connection to an overrunning drive member 68 (which can be simply
an overrunning drive clutch) that in turn connects to the rear end
of the high speed shaft 38a of the generator 22a. Then the forward
end of the shaft 38a of the generator 22a connects to a forward
overrunning drive member 69 that connects to the drive output of
the speed changing drive section 34a. The torque converter 66
located between the auxiliary drive unit 24a and the generator 22a
may or may not be required and depends on the design speed of the
generator 22a and the auxiliary drive unit 24a. If the operating
speed of the auxiliary drive unit 24a is a close match to the
generator 22a operating speed, the overrunning clutch 68 would
provide an adequate method of coupling the generator 22a to the
auxiliary drive unit 24a.
[0047] There are many types of conventional drives that could
function as the auxiliary drive unit 24a. For example, this could
include an internal combustion engine, external combustion engine,
steam turbine, steam engine, or hybrid drive. The most common types
of drives would include, but not be limited to, gasoline engines,
diesel engines, natural gas engines, gas turbine engines, steam
turbines, steam engines, sterling engines, gas expanders, or
hydraulic or electric motors with a nearby source of power or
hydraulic energy. Sources of energy for the auxiliary drive unit
24a could include gasoline, diesel, jet fuel, heavy oil, natural
gas, propane, hydrogen, ethanol, coal, wood, or any other energy
source suitable for the auxiliary drive or its cooperating
equipment.
D. Operation of First Example
[0048] To describe now the operating features of this first
example, let us review three different situations, namely: i. the
wind is at a sufficient velocity so that it is able to generate
sufficient power to produce the desired power output of the
generator 22a; ii. the wind velocity is not sufficient to drive the
blade section at all, and the auxiliary drive section 24a is
activated to generate the needed electric power; and iii. the wind
velocity is such that it is able to rotate the blade section 18a to
generate only an electrical power output which is below the desired
output of the generator 22a, and to obtain the desired level of the
total electrical power output, it is necessary to operate the
auxiliary drive section 24a.
[0049] In the first situation (where the wind power is at a
sufficiently high level), the blade section 18a is rotated to drive
the blade sections 18a at full power output or near full power
output. More specifically, the blade section 18a is rotating with
sufficient power output so that the speed augmenting drive section
20a is acting through an overrunning clutch 69 to drive the
generator 22a at a sufficient power output so that sufficient
electrical power is developed. The overrunning drive section 68,
which connects to the shaft 38a of the generator 22a, simply
overruns its connection to the auxiliary drive section 24a, thus,
the auxiliary drive section 24a remains stationary.
[0050] Let us now take the second situation where there is either
no wind or such a small velocity of the wind that the blade section
18a is put in a position where it is stationary or simply not
rotating. In this situation, the auxiliary drive section 24a is
activated manually or automatically so that its rotational output
is directed through the torque converter 66, which in turn acts
through the overrunning drive 68, which is caused to rotate in a
direction so that it drives the generator 22a.
[0051] At the same time, the speed changing drive section 20a
remains stationary, and since the connection between the drive
section 20a and the generator 22a is the overrunning drive member
69, the generator 22a is able to operate to rotate in a manner so
that it has no drive connection with the drive section 20a and is
driven totally by the auxiliary power unit 24a.
[0052] Let us now consider the third situation, which is that the
wind generated power is great enough to achieve a useful lower
power output level, but is not great enough to meet the desired
power output. In this instance, the auxiliary drive section 24a
would be utilized to cause rotation of its torque converter 66 to
act through its drive member 68 and provide power to the rear end
of the shaft 38a of the generator 22a.
[0053] At the same time, the pitch of the blades 28a could be set
at an angle of attack to optimize the power output that is
developed by the use of both power sources. The effect of this is
that the shaft 38a of the generator 22a would be driven at both its
front and rear end portions, so that there would be sufficient
power to generate the desired electrical power output.
[0054] Also, in this third operating mode, the two overrunning
drive members (drive clutches) 68 and 69 are operating in their
engaged position, so that these are providing rotational forces to
the generator 22a at a sufficiently high power output.
E. Applications of First Example
[0055] Let us now turn our attention to some of the possible
applications of the system of the first example of the invention
(i.e., the various ways it might be used). As indicated earlier in
this text, one of the drawbacks of a wind turbine is that it
produces power intermittently. Thus, this puts wind power in the
category of "non-firm energy producers". However, by combining the
wind power turbine in the combination of this first example, this
now becomes a source of firm power that could supply energy to a
power grid on a continuous basis.
[0056] Another situation of possible use is where there is a
municipality which needs a reliable source of electricity. With the
system of the first example, the system could be engineered so that
the auxiliary power source by itself could generate an adequate
level of electric power. In that situation, the auxiliary power
source would be able to operate as the sole power source in that
time interval when the wind turbine power source would be idle.
Then as the wind energy was available, the system could be operated
in the mode mentioned above as Mode 1 or Mode 2 where the electric
power output would be entirely from the wind turbine or as Mode 3,
a dual drive mode, where the combined operation of both the wind
turbine and the auxiliary power section are utilized to drive the
generator 22a.
[0057] From the above comments, it becomes apparent that only the
one generator 22a would be needed in each of the three modes. There
are various expenses incurred in providing electric power through a
generator, such as the cost of switchgear, transformers, etc. With
this arrangement of this example, that extra expense is alleviated
by utilizing the same generator for: i) the "only wind power mode";
ii) the "sole auxiliary power mode"; and iii) the "combined wind
power/auxiliary power mode".
[0058] It is to be understood that all of the components (or a
large number of the components) that are shown in FIG. 2 could be
utilized also in each of the several examples of the present
invention.
i) Generator Types
[0059] To comment generally on the generator 22a, wind turbines are
supplied with several different types of generators, including
induction generators, double fed induction generators (for speed
control), variable slip induction generators (for limited changes
in speed), synchronous generators (directly and indirectly
connected), and DC generators (typically small wind turbines). Most
wind turbines in service are standard induction generators which
are constant speed machines. Variable speed generators, with the
exception of DC generators, can be held at a fairly constant speed
with the control system. This is a plus for the operation of the
auxiliary drive in that the additional energy input to the
generator does not change the generator speed appreciably.
Additional torque input to the generator simply causes more power
output from the generator. The DC generator is not considered an
ideal candidate for the auxiliary drive as too much torque from the
auxiliary drive could speed up the wind turbine to the point where
the wind would not contribute to energy production.
ii) Auxiliary Drive Considerations
[0060] To comment generally about the different possibilities of
the auxiliary drive 24a, it could be coupled directly to the
generator via a torque converter or overrunning clutch or it can be
connected through a gearbox, again using a torque converter or
overrunning clutch. In most cases, an overrunning clutch will be
sufficient; however, if there is a need to run the engine at
constant speed and vary the output shaft speed to the generator, a
torque converter can be used. If the wind turbine is at rest (zero
speed) and the operator wishes to run the generator, he can start
the auxiliary drive 24a. Because the generator is at rest, the
overrunning clutch will engage the generator as soon as the
auxiliary drive commences startup. The generator rotor will rotate
along with the auxiliary drive shaft during startup and will
continue to rotate at the same speed as the auxiliary drive at all
times.
[0061] To connect the generator to the grid, the auxiliary drive
must speed the generator rotor up to a speed that matches the
generator rotating magnetic field. At that point the generator
breaker can be closed to connect the generator to the grid. Any
additional power input from the auxiliary drive to the is generator
will cause power to flow out of the generator to the grid. An
alternate method of starting up the generator would be to use the
soft start feature supplied with most large scale wind turbines to
connect them to the grid. In this case the wind must be used to
rotate the propeller, gear, and generator to get it close to the
normal operating speed before closing the breaker. In some cases
the soft start feature can be used to start the generator from dead
stop. In this case, the generator acts as a motor until it gets up
to speed at which time the wind energy input causes power to flow
out from the generator.
[0062] If the auxiliary drive had a torque converter, the operator
could start the auxiliary drive and run it up to operating speed
before engaging the torque converter to spin up the generator. With
the torque converter the engine speed could be changed and the
output shaft speed from the torque converter could be held at a
constant speed or, conversely, the engine speed could be kept
constant and the output speed could be varied along with the
generator speed.
[0063] The generator can be driven from the wind turbine end, the
auxiliary drive end, or both ends at the same time. The generator
will not know the difference. It only knows that torque is being
applied to its rotor to generate electricity. It would be possible
to use the auxiliary drive to reduce the impact of wind gusts on
the wind turbine. This could be done by applying a certain amount
of power from the auxiliary drive which is over and above the power
being supplied to the generator from the wind. In this case the
wind turbine would not be supplying full rated power to the
generator. When a wind gust hits the wind turbine and increases the
generator output and causes high loads on the gearbox, the
auxiliary drive would receive a governor signal to reduce its power
output so the generator and gear do not experience damaging load
increases. Wind turbine manufacturers are constantly working on
improvements to minimize the damaging effects of wind gusts and
would welcome new solutions to the problem. The current methods to
control the effect of wind gusts are associated with the electrical
control systems and generators. Variable slip generators are used
to help solve the wind gust problem by allowing the generator to
temporarily speed up (increased generator slip) to allow the
additional wind energy to be converted into kinetic energy and not
forcing the energy through the generator. It would be like
installing a clutch between the wind turbine propeller shaft and
gearbox to allow the clutch to slip during wind gusts to avoid
damage to the gears.
iii) Structural Considerations
[0064] An additional benefit of the auxiliary drive arrangement is
to change the center of gravity of the nacelle. The auxiliary drive
acts as a counterweight on the opposite end of the nacelle as the
propeller, hub, shaft and gearbox. Due to the extreme weight of
those components, the wind turbine nacelle must be positioned to
keep its center of gravity above the center of the tower. This
means the propeller is positioned quite close to the tower which
causes the propeller blades to bend every time they pass by the
wind turbine support tower. The wind shadow and flexing of
propeller blades has caused fatigue failures of blades in the past.
The weight of the auxiliary drive on the opposite end of the
nacelle would allow the nacelle to be repositioned so that the
propeller blades are farther away from the tower and less
susceptible to flexing and fatigue failures.
F. Second Example
[0065] Reference will now be made to FIGS. 4, 4A and 4B which are
different configurations of this second example.
[0066] The second example is similar to the first example except
that some of the auxiliary drive components are placed in different
relative positions, and an auxiliary drive speed changing section
is added in FIGS. 4A and 4B to allow the installation of two
auxiliary drives. An example of the foregoing would be the
installation of a natural gas engine as an auxiliary drive and a
steam turbine as the second auxiliary drive. The second auxiliary
drive would be part of an energy recovery system that would recover
waste heat from the first auxiliary drive and convert the waste
heat into steam. The steam would then be used as an energy input to
the second auxiliary drive. Another example of a use for a second
auxiliary drive would be a solar/wind hybrid wind turbine shown in
FIG. 7 where steam generated in the solar collector is routed to
the second auxiliary drive (steam turbine) to provide additional
power to the generator.
[0067] Components of this second example which are the same as, or
similar to, components shown in FIGS. 1, 2 and 3, will be given
like designations with a "b" suffix distinguishing those of the
second example, and the newly mentioned components are given new
numerical designations. Further, to distinguish between the three
different versions, in the version of FIG. 4, a suffix of "b-1"
will distinguish those of the version of FIG. 4, a suffix of "b-2"
will distinguish those of the second version of 4A, and the suffix
of "b-3" will distinguish those of the third version of FIG.
4B.
[0068] All three of these versions of the second example have the
following components, the blades 28b, the hub 30b, the low speed
shaft 32b, the speed changing section 20b, the generator section
22b, and the auxiliary drive section 24b. In FIG. 4, all of these
components are arranged in substantially the same way as
corresponding components in FIG. 3, except that there are two
auxiliary drive sections 24b-1 and 25b-1. Other specific features
are the same, such as having the torque converter and overrunning
clutches located in substantially the same manner as in the first
example of FIG. 3.
[0069] The first version of the second example of FIG. 4 differs
from the first example in that in addition to the auxiliary drive
24b-1 there is a second auxiliary drive 25b-1 which connects to the
speed changing drive section 20b-1. Power from the auxiliary drive
25b-1 is transmitted through the speed changing drive section 20b-1
to the generator 22b-1 for additional power output. In FIG. 4 an
overrunning clutch 27b-1 must be installed to de-couple the wind
turbine shaft 32b-1 from the speed changing drive 20b-1 when there
is insufficient wind to rotate wind turbine shaft 32b-1.
[0070] In FIG. 4A the second version of FIG. 4, we have the same
components of the wind turbine blades 28b-2, the hub 30b-2, the low
speed shaft 32b-2, the speed changing section 20b-2, the generator
section 22b-2, and the auxiliary power section 24b-2. FIG. 4A
differs from FIG. 4 in that there is provided a second speed
changing section 26b-2 which has an operative connection to the
auxiliary drive section 24b-2. Then there is a second auxiliary
drive section 25b-2 which also has an operative connection through
the second speed changing section 26b-2. The second auxiliary drive
section 25b-2 provides additional power to generator 22b-2 as
available from energy recovery systems or energy generation systems
other than wind, which are part of the hybrid wind turbine
system.
[0071] FIG. 4B has substantially the same components as in FIG. 4A,
except that in addition to the auxiliary drive section 24b-3
transmitting power through the second speed changing section 26b-3,
the second auxiliary drive section 25b-3 is located on the same
side of the second speed changing section 26b-3. In other respects,
it functions the same way as the second version of FIG. 4A.
G. Third Example
[0072] A third example of the present invention will now be
described with reference to FIGS. 5 and 5A. Components of this
third example which are the same as, or similar to, components of
the earlier examples will be given like numerical designations,
with a "c" suffix distinguishing those of the third example.
[0073] In this third example, the basic system as shown in FIG. 3
is used, so that the main components and their functions of this
third example are substantially the same as in the third example as
they are in the first example. However, the added feature is that
the auxiliary engine drive is combined with two stages of an
organic rankine cycle heat recovery system to increase the overall
efficiency of the engine drive.
[0074] In this example the two stages of heat recovery 50c and 51c
are located in the wind turbine support tower 11c.
[0075] With this system, the heat recovery process captures waste
heat from the auxiliary engine 24c exhaust and the auxiliary engine
24c coolant. Also, the waste heat is converted into useful
electricity using a separate turbine and generator which is part of
the heat recovery system located in the tower 11c.
[0076] In FIG. 5A the hot exhaust from auxiliary drive engine 24c
flows to an organic rankine cycle boiler 52c to vaporize the
organic working fluid. The cooled exhaust then flows to an emission
control unit 53c before being discharged to atmosphere. The rankine
cycle involves a boiler feed pump 54c which pumps the organic
working fluid to the boiler 52c for vaporization. The vapor then
flows to the expansion turbine 55c which is coupled to a generator
56c. Power from the generator 56c is connected to the wind turbine
electrical switchgear. The vapor then flows out of the expansion
turbine to the air cooled condenser 57c where it is condensed back
into a liquid. The liquid working fluid then flows back to the
boiler feed pump 54c for recirculation.
[0077] In this example the auxiliary drive engine coolant is routed
from auxiliary drive engine 24c to an organic rankine cycle boiler
58c to vaporize the organic working fluid. The cooled engine
coolant is then pumped back to engine 24c using coolant circulation
pump 59c. The rankine cycle involves a boiler feed pump 60c which
pumps the organic working fluid to the boiler 58c for vaporization.
The vapor then flows to the expansion turbine 61c which is coupled
to a generator 62c. Power from the generator 62c is connected to
the wind turbine electrical switchgear. The vapor then flows out of
the expansion turbine 61c to the air cooled condenser 63c where it
is condensed back into a liquid. The liquid working fluid then
flows back to the boiler feed pump 60c for recirculation.
[0078] With the conversion of waste energy into additional
electricity, the auxiliary drive 24c is a very efficient source of
additional power for the hybrid wind turbine.
H. Fourth Example
[0079] FIG. 6 shows a fourth example of the present invention.
Components of this fourth example which are the same as, or similar
to, components of the earlier example will be given like numerical
designations, with a "d" suffix distinguishing those of the fourth
example. This fourth example has the same basic operating
components as shown in the first example, except that in this to
fourth example, the auxiliary drive section 24d is steam powered.
Further, the steam that is generated to supply the power is
generated by a boiler that is located in the support tower 11d. The
fuel can be solid fuel, liquid fuel, gaseous fuel, or other
fuels.
[0080] As shown in FIG. 6, there is the support structure 13d
mounted to the tower 11d, the blade section 18d, a speed changing
drive section 20d, and a generator 22d. There are also the two
overrunning drive members 68d and 69d on opposite sides of the
generator 22d.
[0081] There is a solids fuel hopper 90, which directs the solid
fuel 92 into a furnace area 94, where there is a forced draft
generated by the fan 96. Further, there is a liquid and/or natural
gas burner 98, a steam drum 100, a mud drum 102, a boiler flue gas
discharge 104, and a bag house 106. There is a steam conduit 108
leading to a steam drive turbine 110. The steam drive turbine 110
is positioned to supply power to the generator 22d. The steam
exhaust from the steam turbine 110 flows along a conduit 112 to an
air cooled surface condenser 114 and is cooled by a fan 116. The
condensate then flows to the feed water pump 105 and back to the
boiler steam drum 100.
I. Fifth Example
[0082] A fifth example of the present invention will now be
described with reference to FIG. 7. Components of this fifth
example which are the same as, or similar to, components of any of
the earlier examples will be given like numerical designations,
with an "e" suffix distinguishing those of this fifth example.
[0083] In this fifth example, there is a solar thermal power source
in addition to the wind turbine power and also the auxiliary power
section. In this case, there would be three sources of power to
drive the generator, namely: i) wind; ii) solar generated power;
and iii) the auxiliary drive section which, as indicated previously
in this text, could be fueled by a wide variety of energy sources,
such as an engine driven by diesel fuel, natural gas, ethanol,
etc.
[0084] The wind and solar energy inputs would produce non-firm
energy that cannot be depended upon as a constant source of power.
However, the auxiliary drive 24e (engine or turbine) would be the
ultimate backup for firm power generation. Thus, with these three
options offered with the wind turbine, the customer could purchase
a basic wind turbine, a wind turbine with a solar thermal energy
drive, a wind turbine with an engine or turbine (steam, gas
turbine, etc.) auxiliary drive, or a wind turbine with both a solar
thermal energy drive and an engine or turbine drive. Thus,
different sources of energy input to the wind turbine are not
mutually exclusive and can cooperate to maximize the output of the
wind turbine. With that background information having been given,
FIG. 7 shows the basic components that are shown in the first
example of FIG. 3, and the components discussed above with
reference to FIG. 7.
[0085] Thus, there is the source of firm power in the form of an
auxiliary drive engine 24e or other power source (see FIG. 7A).
[0086] In this example, in FIG. 7 there is the tower 11e which
supports the rotatably mounted support structure 13e, the speed
changing drive section 20e, and the generator 22e. FIG. 7 shows the
engine auxiliary drive 24e-1 and the auxiliary drive 25e-1 in the
form of a steam turbine. There is a condenser 152 which directs the
condensate to the boiler feed pump 134.
[0087] To provide the solar energy, FIG. 7 shows there is a
plurality of heliostats 130 which reflect the sun rays in a
converging pattern to a solar absorber 132 that is mounted in the
tower 11e. FIG. 7 shows there is a boiler feed pump 134 which pumps
water or other liquid up through the solar absorber 132 to a steam
drum 136 so that the steam can be separated from the steam and
water mixture generated in the solar absorber 132. The steam or
other gaseous drive medium then travels upwardly to a steam turbine
25e-1. The steam turbine auxiliary drive 25e-1 provides a rotary
power output to is the generator 22e-1 in combination with the
engine auxiliary drive power output 24e-1, or through another
operative connection to the generator 22e-1.
[0088] In operation, either or both of the non firm power sources
(i.e., the wind power source and the solar power source) are
utilized to provide the energy output to rotate the generator
22e-1. In the event that either or both of the wind power and solar
power are absent because of the surrounding weather environment,
and are producing no usable power, or only a smaller output of
power, then the auxiliary power source 24e-1 can be used to
supplement the power input to an adequate level. However, if the
solar power source and/or the wind power source are adequate, then
the auxiliary power section 24e-1 will not be required.
J. Sixth Example
[0089] A sixth example of the present invention will now be
described with reference to FIG. 8. Components of this sixth
example which are the same as, or similar to, components of any of
the earlier examples will be given like numerical designations with
an "f" suffix distinguishing those of this sixth example.
[0090] In this sixth example, there is an addition of a steam
rankine cycle heat recovery system to recover heat from the engine
auxiliary drive exhaust. To describe this sixth example, reference
is made to FIG. 8.
[0091] Hot engine exhaust leaving the auxiliary drive exhaust flows
to a heat recovery steam generator 144f where the heat in the
exhaust generates steam. The cooled exhaust then flows to the
emission control unit 146f for treatment before it is discharged to
atmosphere.
[0092] A boiler feed water pump 148f pumps water to the heat
recovery steam generator 144f to raise steam. The steam and water
mixture flows to a steam drum 149f, which is part of the heat
recovery steam generator 144f, to allow the steam to separate from
the mixture and flow to a steam turbine auxiliary drive 25f. This
steam turbine 25f converts the steam energy into mechanical work by
turning the turbine wheel and driving the auxiliary speed changing
drive section 26f and the generator 22f through overrunning
clutches 68f and 69f.
[0093] After giving up a portion of its energy to the steam turbine
25f, the steam flows to an air cooled condenser 152f where it is
condensed back into water. The steam condensate then flows through
a vacuum deaerator 154f for oxygen removal before flowing to the
boiler feed water pump 148f which pumps the feed water back to the
heat recovery steam generator 144f to generate more steam.
[0094] The addition of the heat recovery system to the engine
auxiliary drive increases the overall thermal efficiency of the
engine auxiliary drive. Several types of steam drivers can be used
to drive the generator. An example of an alternate type of steam
drive would be a rotary screw steam drive machine.
K. Seventh Example
[0095] A seventh example of the present invention will now be
described with reference to FIG. 9. Components of this seventh
example which are the same as, or similar to, components of earlier
examples will be given like numerical designations, with a "g"
suffix distinguishing those of this seventh example.
[0096] This seventh example comprises a solar thermal energy system
which combines the benefits of wind power with solar power using
the same turbine structure.
[0097] In this example, the entire solar thermal energy system is
separated from the wind turbine power generation system. The solar
thermal system uses an organic ranking cycle heat recovery system
to convert solar energy into electricity. FIG. 9 shows the process
flow for the solar thermal system. The system components can be
located in the support tower or the nacelle substructure of the
ninth example.
[0098] As shown in FIG. 9 there is a solar energy input to a solar
absorber 190g which provides heat to a high temperature heat
transfer fluid which is pumped through the absorber 190g using
circulating pump 189g. The heat transfer fluid then passes through
a heat exchanger 192g where it vaporizes the organic rankine cycle
working fluid. The cooled heat transfer fluid then flows back to
the circulation pump 189g where it is pumped back to the solar
absorber 190g. The vaporized organic fluid flows out of the heat
exchanger 192g and into the expander turbine 193g. The expander
turbine 193g is coupled to a generator 194g which produces electric
power. The vaporized working fluid, usually propane or butane,
passes through the expander turbine to a condenser 195g where it is
condensed back to a liquid. The liquid then flows to a pump 196g
which pumps the working fluid back to the exchanger 192g for
conversion back into a vapor. An expansion tank 197g is provided to
allow for the expansion of the heat transfer fluid in the solar
thermal system.
[0099] In addition to the cost savings of combining the wind and
solar energy to systems in one structure, the solar addition to the
wind turbine has the added benefit of providing additional power
output during the daylight hours when it is needed most.
L. Eighth Example
[0100] An eighth example of the present invention will now be
described with reference to FIG. 10. Components of this eighth
example which are the same as, or similar to, components of earlier
examples will be given like numerical designations, with an "h"
suffix distinguishing those of this eighth example.
[0101] This eighth example comprises a solar thermal energy system
and an engine system with heat recovery which combines the benefits
of wind power, solar power, and engine power using the same wind
turbine support structure.
[0102] FIG. 10 shows the process flow for the combined solar
thermal system and engine system with heat recovery. In the engine
plus heat recovery system, hot engine exhaust leaving the engine
24h flows to a heat recovery steam generator 144h where the heat in
the exhaust generates steam. The cooled exhaust then flows to the
emission control unit 146h for treatment before it is discharged to
the atmosphere. A boiler feed water pump 148h pumps water to the
heat recovery steam generator 144h to raise steam. The steam and
water mixture flows to a steam drum 149h, which is part of the heat
recovery steam generator 144h, to allow the steam to separate from
the mixture and flow to the steam turbine auxiliary drive 25h. The
steam turbine 25h converts the steam energy into mechanical work by
turning the turbine wheel and driving the gear 26h and generator
22h through overrunning clutches. After giving up a portion of its
energy to the steam turbine 25h, the steam flows to an air cooled
condenser 152h where it is condensed back into water. The steam
condensate then flows through a vacuum de-aerator 154h for oxygen
removal before flowing to the boiler feed water pump 148h which
pumps the feed water back to the heat recovery steam generator 144h
to generate more steam.
[0103] In the solar thermal system, the solar energy input to a
solar absorber 132h is converted into steam which drives a steam
turbine 25h which is coupled to the wind turbine main generator
22h. The steam then exits the steam turbine 25h and flows to an air
cooled condenser 152h where the steam is condensed back into water.
The water then flows through a vacuum deaerator 154h to remove
oxygen and then to the feed water circulating pump 148h where it is
pumped back to the solar absorber to generate more steam.
M. Ninth Example
[0104] This ninth example of the present invention will now be
described with reference to FIG. 11. Some of the components in this
ninth example which are substantially the same as, or similar to,
corresponding components of earlier examples will be given like
numerical designations, with an "i" distinguishing those of this
ninth example. Accordingly, there are the propeller blades 28i
along with the hub 30i. There is also the speed changing power
section 20i, the generator 22i, and auxiliary speed changing
section 26i, an auxiliary drive section 24i, and a second auxiliary
drive power 25i, which in this instance is in the form of a steam
driven turbine.
[0105] This ninth example differs from the earlier examples in that
the support structure (i.e., the nacelle 13i) has a nacelle
substructure 141i to provide additional working areas for various
purposes, such as to house heat recovery equipment associated with,
for example, an auxiliary steam turbine drive.
[0106] The existing technology utilizes space in the wind turbine
support tower and nacelle to house all equipment necessary to
operate a wind turbine. At times it can be a challenge to install
all equipment in the allowable space in a cost efficient manner and
there is very little room for any extra equipment. Because the
nacelle rotates to keep the wind turbine blades facing the wind,
any equipment located in the support tower which must cooperate
with equipment in the nacelle must address the problem of rotation.
This means the design must incorporate flexible joints, cables,
hoses and other interconnections that allow the necessary rotation.
By installing a nacelle substructure below the nacelle and on the
downwind side of the support tower, it is possible to provide a
large amount of space to mount equipment which rotates with the
nacelle. Thus, the problem of interfacing equipment that does not
rotate with equipment that does rotate is eliminated.
[0107] Another advantage of nacelle substructures is that it can be
shop fabricated and lifted by crane to attach to the underside of
the nacelle. Because the nacelle substructure is designed with a
width that is no wider than the support tower, there are no
detrimental effects to efficient air flow across the tower which
would have a negative impact on the wind turbine output. To the
contrary, the shape of the nacelle substructure enclosure will act
like a tail behind the tower to assist in yaw control.
[0108] This ninth example can be advantageous to any of the options
described in earlier examples, including a standard wind turbine
without any of these options. The substructure could be used with a
standard wind turbine to house the electrical gear or other
equipment located in the tower to achieve a cost savings during
manufacturing. Due to the extremely tall support towers, it is
possible to design the height of the substructure such that it
extends down the tower as required to house all equipment intended
to be located in the tower.
[0109] Although an auxiliary engine drive 24i and steam turbine
drive 25i are shown coupled to the auxiliary gear 26i, various
other configurations shown in other options are equally suited to
cooperate with the nacelle substructure. For example, in FIG. 11,
there is shown in the upper part of the substructure a heat
recovery steam generator or organic rankine cycle heat recovery
equipment, generally designated 260i. Then below this there are air
cooled condensers indicated at 262i. Below the nacelle substructure
141i there is a support structure 272i which provides support for
the substructure, and which could also provide support for at least
part of the nacelle 13i itself. This support structure 272i
comprises a pair of circumferential rings 274i which are connected
to the tower 11i, and there are roller bearings 268i which are
rotatably mounted for circular movement on the rings 274i around
the tower 11i. Then the support structure 272i of the substructure,
such as indicated at 278i, is supported by these bearing rings.
[0110] The nacelle substructure has the same width as the tower.
Thus, the substructure can be extended further down the tower to
accommodate additional equipment. There are various options which
include the following: i) an engine only configuration in the
nacelle; ii)/HRSG/Steam Turbine/Air Cooled Condenser; iii)
engine/orc heat recovery/ajr cooled condenser; iv) solar steam
generator/steam turbine/air cooled condenser; v) engine/HRSG/solar
steam generator/steam turbine/ajr cooled condenser; vi) solar
thermal heat absorber (heat transfer fluid)/orc heat recovery/air
cooled condenser; vii) engine/solar thermal heat absorber (heat
transfer fluid)/orc heat recovery/air cooler.
[0111] The nacelle substructure 141i is attached to the underside
of the nacelle such that it rotates with the nacelle. Various
pieces of equipment 260i can be located within the substructure on
various levels. Examples are heat recovery equipment 260i, air
cooled condensers 262i and cooling fans 264i. As indicated above,
the structural supports 272i for the nacelle substructure are
supported by the tower using metal support rings 274i enable the
nacelle with roll around the support rings 274i when the nacelle
rotates to face the wind. Solar thermal absorbers 280i are located
on the support tower itself.
[0112] Obviously, the vertical dimension of the nacelle
substructure could vary substantially. In the representation of the
sub-nacelle in FIG. 1, its depth dimension (indicated at "b" in
FIG. 11), is about 40% of the horizontal length dimension
(indicated at "a" in FIG. 11), extending from the forward working
end of the nacelle to the rear working end. Obviously, this
vertical dimension "b" could be increased or decreased
substantially, depending upon various factors. For example, this
40% dimension could be decreased down to about 30%, 20%, 15%, or
10%, or even as low as about 5%. Also, it could be greatly
increased to values of, for example, 50%, 75%, 100%, 150%, 200%,
250%, 300%, 400%, 500%, or even possibly higher.
[0113] The nacelle substructure is an elegantly simple method of
providing large amounts of space for equipment which rotates along
with the nacelle and thereby eliminating the problem of interfacing
rotating and non-rotating equipment. The additional weight will
also be a counterweight to the wind turbine blades and will allow
them to be located further from the tower, thus, reducing the blade
flex when the blades pass by the tower.
[0114] To summarize at least some of the features of the present
invention, the examples of the present invention provide the
following advantages: i) the auxiliary drive system will allow a
wind turbine to generate firm power rather than non-firm energy;
ii) the hybrid wind turbine which incorporates the solar thermal
heat recovery system into the wind turbine allows the same
generator, switchgear, support tower, real estate, and transmission
lines to be used by both the wind turbine and solar thermal power
generator; iii) the nacelle sub-structure provides additional space
to install equipment that must move with the equipment in the
nacelle such as heat recovery steam generators, air coolers,
organic rankine cycle heat recovery systems and electrical gear;
iv) the nacelle sub-structure enclosure will act as a tail fin on
the wind turbine to assist with yaw control; v) the nacelle
sub-structure module can be constructed in a shop with ideal
working conditions thus improving worker productivity and reducing
construction costs; vi) the equipment located in the nacelle
sub-structure can be installed in an upright position and remain in
an upright position throughout the construction process (equipment
located in the support tower must be turned on its side at some
point during the shop fabrication, shipment, or construction
process); vii) the energy conversion efficiency in BTU/KWH of the
hybrid wind turbine which uses wind, and/or solar and/or thermal
energy inputs in one combined system is very efficient when
compared with the heat rate in BTU/KWH of a thermal energy
conversion system alone due to the non-thermal energy inputs from
the wind and solar systems; viii) all components of the hybrid wind
turbine can be procured and constructed using commercially
available equipment and commercially available engineering and
construction practices; and ix) the nacelle sub-structure provides
an alternate escape route for operations personnel in the event of
a fire in the nacelle.
N. Tenth Example
[0115] Referring now to FIG. 12, depicted therein is yet another
example of a hybrid wind turbine system 320 of the present
invention. The example hybrid wind turbine system 320 comprises a
tower structure 322 capable of supporting the system 320 in a
desired orientation. The tower structure 322 in turn supports a
nacelle 324 and blades 326. As is conventional, the example nacelle
324 is mounted on the tower structure 322 such that the nacelle 324
may rotate to optimize the orientation of the blades 326 with
respect to the wind at any point in time. FIG. 12 further shows
that electrical switch gear 328 may be mounted within the nacelle
324.
[0116] The blades 326 are mounted on a hub 330 that is rotatably
supported by the nacelle 324. In particular, the hub 330 may be
conventionally is supported by a generator shaft 332 of a generator
334. Accordingly, air movement rotates the blades 326 to cause the
generator 334 to generate electricity.
[0117] In the example system 320, the generator shaft 332 is in
turn connected to a gearbox 336 through a first overrunning clutch
338. The gearbox 336 is connected to a variable speed drive 340
through a second overrunning clutch 342. The variable speed drive
340 is connected to an auxiliary drive engine 344 through a
coupling 346. The auxiliary drive engine 344 is connected to a fuel
line 348 connected to a conventional fuel source (not shown) such
as fuel storage tanks or utility fuel lines. The fuel line 348
depicted in FIG. 12 represents both a conduit for carrying fuel and
the fuel carried by the conduit.
[0118] Accordingly, when desired, the auxiliary drive engine 344
may be operated to rotate the generator shaft 332 through the
coupling 346, variable speed drive 340, second overrunning clutch
342, gearbox 336, and first overrunning clutch 338. Operation of
the auxiliary drive engine 344 thus causes the generator 334 to
generate electricity.
[0119] As with others of the example systems described above, the
auxiliary drive engine 344 of the example system 320 is located in
the top portion 350 of the system 320. In the example system 320,
the top portion 350 containing the auxiliary drive engine 344 is
located below the nacelle 324 within an upper end of the tower
structure 322.
[0120] An exhaust line 352 connects the auxiliary drive engine 344
to a heat to recovery system 354 located at a lower portion 356 of
the system 320. Again, the exhaust line 352 depicted in FIG. 12
represents both engine exhaust and the conduit for carrying that
exhaust. The example heat recovery system 354 is depicted within a
lower end of the tower structure 322, but this system 354 may be
located at least partly outside of the tower structure 322. The
heat recovery system 354 may be implemented using any suitable
system for reclaiming or generating energy from heat.
[0121] The example configuration depicted in FIG. 12 thus allows
the auxiliary drive engine 344 to be mounted in a nonmovable
section of the wind turbine system 320, in this case the tower
structure 322. Mounting the auxiliary drive engine 344 within a
nonmovable portion of the wind turbine system 320 allows exhaust
from the engine 344 to be ducted down the tower structure 322 to
heat recovery equipment located in the tower, or at the base of the
tower, rather than to a substructure attached to the rotating
nacelle 324.
O. Eleventh Example
[0122] Referring now to FIG. 13, depicted therein is yet another
example of a hybrid wind turbine system 420 of the present
invention. The example hybrid wind turbine system 420 comprises a
tower structure 422 capable of supporting the system 420 in a
desired orientation. The tower structure 422 in turn supports a
nacelle 424 and blades 426. As is conventional, the example nacelle
424 is mounted on the tower structure 422 such that the nacelle 424
may rotate to optimize the orientation of the blades 426 with
respect to the wind at any point in time. FIG. 13 further shows
that electrical switch gear 428 may be mounted within the nacelle
424.
[0123] The blades 426 are mounted on a hub 430 that is rotatably
supported by the nacelle 424. In particular, the hub 430 may be
conventionally supported by a generator shaft 432 of a generator
434. Accordingly, air movement rotates the blades 426 to cause the
generator 434 to generate electricity.
[0124] In the example system 420, the generator shaft 432 is in
turn connected to a gearbox 436. In this example system 420, the
blades 426 are located on an opposite end of the nacelle 424 from
the generator 434, and the gearbox 436 is arranged between the
blades 426 and the generator 434. An overrunning clutch 438 may be
connected between the hub 430 and the gear box 436.
[0125] The gearbox 436 is connected to a fluid drive reduction gear
440 through an overrunning clutch 442. The fluid drive reduction
gear 440 is connected to an auxiliary drive engine 444 through a
coupling 446. The auxiliary drive engine 444 is connected to a fuel
line 448 connected to a conventional fuel source (not shown) such
as fuel storage tanks or utility fuel lines. The fuel line 448
depicted in FIG. 13 represents both a conduit for carrying fuel and
the fuel carried by the conduit.
[0126] Accordingly, when desired, the auxiliary drive engine 444
may be operated to rotate the generator shaft 432 through the
coupling 446, fluid drive reduction gear 440, overrunning clutch
442, and gearbox 436. Operation of the auxiliary drive engine 444
thus causes the generator 434 to generate electricity.
[0127] As with others of the example systems described above, the
auxiliary drive engine 444 of the example system 420 is located in
the top portion 450 of the system 420. In the example system 420,
the top portion 450 containing the auxiliary drive engine 444 is
located below the nacelle 424 within an upper end of the tower
structure 422.
[0128] An exhaust line 452 connects the auxiliary drive engine 444
to a heat recovery system 454 located at a lower portion 456 of the
system 420. Again, the exhaust line 452 depicted in FIG. 13
represents both engine exhaust and the conduit for carrying that
exhaust. The example heat recovery system 454 is depicted within a
lower end of the tower structure 422, but this system 454 may be
located at least partly outside of the tower structure 422. The
heat recovery system 454 may be implemented using any suitable
system for reclaiming or generating energy from heat.
[0129] FIG. 13 thus illustrates another embodiment of a hybrid wind
turbine of the present invention in which the auxiliary drive
engine located in the top portion of the wind turbine tower below
the nacelle. In this example, the generator 434 is a slow speed
multi-pole generator. As with the example discussed in connection
with FIG. 12, the auxiliary drive engine 444 is located in the
non-movable section of the wind turbine, which allows the engine
exhaust 452 to be ducted down through the tower structure 422 to
heat recovery equipment 454 located in the tower structure 422, or
at the base of the tower structure 422, rather than to a
substructure which is attached to or located within the rotating
nacelle 424.
[0130] Accordingly, in the example system shown in FIG. 13, the
wind imparts energy to the wind turbine blades 426 which cause
rotation of the blades 426 and the hub 430. The blade hub 430 is
connected to the generator shaft 432; axial rotation of the
generator shaft 432 turns the generator 434. The example generator
434 is a multi-pole type generator, such as a permanent magnet
generator, and operates at the rotor speed of the wind turbine
blades 426. In this configuration, a speed reduction gear is not
required to allow the generator 434 to be connected to the shaft
432 connected to the hub 430. The generator can operate at various
rotational speeds and produces alternating current which may or may
not be at a standard frequency of 50 or 60 cycles per second. To
correct for any frequency offset from a desired frequency, the
output of the generator is converted to direct current and
subsequently rectified back to 50 or 60 cycle AC current. By
allowing the generator to operate at various speeds, turbine
manufacturers are able to optimize the wind turbine efficiency for
various wind speeds.
[0131] In FIG. 13, the coupling 446 and fluid drive reduction gear
440 reduce the rotational speed of the output shaft of the
auxiliary drive engine 444. Additionally, the example engine 444
and the fluid drive reduction gear 440 are fixed in the axial
center of the tower and do not rotate with the nacelle 424. The
clutch 442 connects the fluid drive reduction gear 440 to the
gearbox 436; the example gearbox 436 is a 90 degree speed reduction
gearbox. The example gearbox 436 thus reduces the rotational speed
of the output shaft of the engine 444 to a speed appropriate for
driving the generator 434. The clutch 442 located between the
gearbox 436 and the fluid drive reduction gear 440 allows the
engine 444 to be disconnected from the gearbox 436 when the engine
444 is not in use. The engine 444 can operate simultaneously with
the wind turbine to provide firm power output or it can operate
independently if the wind turbine is idle (e.g., too little
wind).
[0132] Although not shown in FIG. 13, the components that connect
the fluid drive reduction gear 440 to the gearbox 436 may be a
drive shaft with universal joints or an angle drive gear assembly.
An angle drive gear assembly attached to gearbox 436 is capable of
compensating for the small horizontal offset angle of equipment
located in the nacelle 424. Conventionally, the angular
relationship between the wind turbine equipment mounted in the
nacelle and the wind turbine tower is not perpendicular. When the
blades are driven by wind, this non-perpendicular relationship
allows the blades to maintain a greater distance from the tower
when they pass by the tower during operation, which reduces the
flexing of the blades and, thus, reduces the probability of blade
fatigue failure.
P. Twelfth Example
[0133] Referring now to FIGS. 14-17, depicted therein is a twelfth
example hybrid wind turbine system 520 of the present invention.
The example hybrid wind turbine system 520 comprises a tower
structure 522 capable of supporting the system 520 in a desired
orientation. The tower structure 522 in turn supports a nacelle 524
and blades 526. As is conventional, the example nacelle 524 is
mounted on the tower structure 522 such that the nacelle 524 may
rotate to optimize the orientation of the blades 526 with respect
to the wind at any point in time. FIG. 14 further shows that
electrical switch gear 528 may be mounted within the nacelle
524.
[0134] The blades 526 are mounted on a hub 530 that is rotatably
supported by the nacelle 524. In particular, the hub 530 may be
conventionally supported by a generator shaft 532 of a generator
534. Accordingly, air movement rotates the blades 526 to cause the
generator 534 to generate electricity.
[0135] In the example system 520, the generator shaft 532 is in
turn connected to a gearbox 536 through a first overrunning clutch
538. The gearbox 536 is connected to a variable speed drive 540
through a second overrunning clutch 542. The variable speed drive
540 is connected to an auxiliary drive engine 544 through a
coupling 546. The auxiliary drive engine 544 is connected to a fuel
line 548 connected to a conventional fuel source (not shown) such
as fuel storage tanks or utility fuel lines. The fuel line 548
depicted in FIG. 14 represents both a conduit for carrying fuel and
the fuel carried by the conduit.
[0136] Accordingly, when desired, the auxiliary drive engine 544
may be operated to rotate the generator shaft 532 through the
coupling 546, variable speed drive 540, second overrunning clutch
542, gearbox 536, and first overrunning clutch 538. Operation of
the auxiliary drive engine 544 thus causes the generator 534 to
generate electricity.
[0137] As with others of the example systems described above, the
auxiliary drive engine 544 of the example system 520 is located in
the top portion 550 of the system 520. In the example system 520,
the top portion 550 containing the auxiliary drive engine 544 is
located below the nacelle 524 within an upper end of the tower
structure 522.
[0138] An exhaust line 552 connects the auxiliary drive engine 544
to a heat recovery system 554 located at a lower portion 556 of the
system 520. Again, the exhaust line 552 depicted in FIG. 14
represents both engine exhaust and the conduit for carrying that
exhaust. The example heat recovery system 554 is depicted within a
lower end of the tower structure 522, but this system 554 may be
located at least partly outside of the tower structure 522. The
heat recovery system 554 may be implemented using any suitable
system for reclaiming or generating energy from heat.
[0139] The example configuration depicted in FIG. 14 thus allows
the auxiliary drive engine 544 to be mounted in a nonmovable
section of the wind turbine system 520, in this case the tower
structure 522. Mounting the auxiliary drive engine 544 within a
nonmovable portion of the wind turbine system 520 allows exhaust
from the engine 544 to be ducted down the tower structure 522 to
heat recovery equipment located in the tower, or at the base of the
tower, rather than to a substructure attached to the rotating
nacelle 524.
[0140] As will be explained in further detail below, the example
wind turbine system 520 further comprises a solar absorber system
560. The solar absorber system 560 is secured at a desired
elevation relative to the tower structure 522; a solar heat line
562 carries heated fluid from the solar absorber system 560 to the
heat recovery system 554 as will be described in further detail
below.
[0141] The drawings further illustrate an absorber housing 566 and
a layer of heat absorption material 568 on or forming a part of the
housing 566. The heat absorption material 568 has desirable heat
transfer properties and typically will be, or be coated with, a
color, such as black, that facilitates the absorption of heat.
[0142] FIG. 14 shows the heat recovery system 554 and the solar
absorber system 560 can be configured to recover both solar heat
and heat generated by the auxiliary drive engine 544. FIGS. 14-16
only show the components of solar absorber system 560 on one side
of the wind turbine tower for illustrative purposes. A wind turbine
system incorporating a solar absorber system may have a first
section facing east and a second section facing west to optimize
absorption of solar energy during morning and afternoon.
Additionally, one or more heliostats 564 may be arranged to direct
solar rays onto the solar absorber system 560.
[0143] As is conventional, wind imparts energy to the wind turbine
blades 526 which move the blades 526 and blade hub 530. The blade
hub is connected to a shaft 532 which turns the generator 534. The
example generator 534 used in this embodiment is preferably, but
not necessarily, capable of operating at a very low speed to
obviate the need for a speed reduction gear to allow the generator
to be connected to the generator shaft 532. The example generator
534 is an AC permanent magnet generator that can operate at various
rotational speeds and produces alternating current which may or not
be at a standard frequency of 50 or 60 cycles per second. To
correct for this possible deviation from the desired frequency, the
output of the generator 534 is converted to direct current and
subsequently rectified back to 50 or 60 cycle AC current. By
allowing the generator 534 to operate at various speeds, wind
turbine efficiency can be optimized for various wind speeds.
[0144] FIG. 14 illustrates that the auxiliary engine 544 is
connected to the coupling 546, which is in turn connected to a
fluid drive reduction gear 540 to reduce the speed of the drive
shaft of the auxiliary drive engine 544. The example drive engine
544 and the fluid drive reduction gear 540 are fixed in the center
of the tower and do not rotate with the nacelle. The coupling 542
connects the fluid drive reduction gear 540 to the speed reduction
gearbox 536. The speed reduction gearbox 536 reduces the output
shaft speed of the fluid drive reduction gear 540 to match the
speed of the generator 534. The clutch 538 is located between the
speed reduction gearbox 536 and the generator 534 to allow the
generator 534 to be disconnected from the speed reduction gearbox
536 when the engine 544 is not in use. However, the engine 544 can
operate simultaneously with the wind turbine to provide a firm
power output, or the engine 544 can operate independently if the
wind turbine is idle.
[0145] Referring now to FIGS. 15 and 16, a solar absorber 610 is
mounted within the absorber housing 656. An example engine exhaust
line 612 routes the engine exhaust to an engine exhaust heat
exchanger 620 portion of the heat recovery system 660. The engine
exhaust then flows through an emission control device 670 and an
engine exhaust shutoff damper 650. Engine exhaust then flows from
the engine exhaust shutoff damper 650 to an annular space 656
between solar absorber tubes 630 and tower wall insulation 638 to
transfer more waste heat to the back side of the solar tubes
630.
[0146] A combustion air fan 648 draws ambient combustion air
through an opening 646 in the tower structure 522 and sends it to
the solar absorber burner 640. The burner 640 combusts gas or
liquid fuel 642 with engine exhaust 612, combustion air, or a
mixture of engine exhaust 612 and combustion air. The flue gas from
the burner 640 flows upward in the annular space 656 between the
absorber tubes 630 and tower wall insulation 638 and transfers heat
to the absorber tubes 630. The combination of solar energy directed
onto the outside of the solar absorber tubes 630, waste heat
carried by the exhaust 612, and heat from combusting the
supplemental fuel 642 directed to the inside of the solar absorber
tubes 630 allows the solar absorber 610 to supply thermal energy
continuously, if desired, during daytime or night time hours. This
design feature allows the solar absorber 610 to be classified as a
hybrid solar absorber.
[0147] FIG. 16 further illustrates a heat exchanger inlet 622, heat
exchanger outlet 624, and burner combustion air duct 644. FIG. 15
illustrates optional cooling lines 660.
[0148] A heat transfer fluid is pumped through heat transfer fluid
inlets 632 in the solar absorber tubes 630 to absorb heat from the
solar and thermal energy sources. The hot heat transfer fluid flows
out of outlets 634 in tubes 630 forming the solar absorber 610 to
an organic rankine cycle heat recovery system turbine/generator or
a conventional rankine cycle system turbine/generator to convert
the thermal energy into electrical energy. Components of the
Rankine cycle other than the solar absorption tubes 630, engine
exhaust heat exchanger 620, and emission control device 670,
combustion air fan 648, associated dampers and controls, and burner
640 can be located, if desired, at ground level at the base of the
tower structure 522 as described herein. Thermal insulation 638 is
applied to the outside of the wind turbine tower structure 522 to
prevent overheating due to a mis-directed solar reflector which
normally directs the solar rays onto the solar absorber tubes
630.
[0149] A tower manway 658 allows access to the solar absorber
access duct 656. The solar absorber access duct also allows access
to the fin-fan air coolers 662 which are mounted on the wall of the
solar absorber access duct to 656. The fin-fan air coolers 662
reject waste heat from the rankine cycle heat transfer fluid to
condense the fluid from the vapor state to the liquid state. The
fin-fan coolers 662 can also be mounted on the ground at the base
of the tower structure 522, if desired. The tower manway 658 also
allows access to the solar absorber tubes 630. A tower manway 664
and platform 666 allow access to the burners 640 for
maintenance.
[0150] Referring now to FIG. 17, depicted therein is a process flow
diagram illustrating an example energy recovery system that may be
used with the heat recovery system of the example wind turbine
systems of the present invention. For illustration purposes, the
example energy recovery system shown in FIG. 17 is the heat
recovery system 554 of the example wind turbine system 520
described above.
[0151] The example energy recovery system 554 depicted in FIG. 17
utilizes an organic rankine cycle heat recovery system. As
generally discussed above, a hybrid wind turbine system
incorporating this system 554 utilizes wind energy acting on blades
526 to turn a generator 534 to produce electricity, solar energy
from the sun to produce electricity using an organic rankine cycle,
and an engine 544 to generate supplemental or emergency power using
conventional fossil fuels. The hot flue gas from the engine 544
flows through a heat exchanger 720 where it transfers heat to a
circulating heat transfer fluid. The flue gas then passes through
an emission control device 670 and then to the burner 640 before
entering the solar absorber 610 where it passes by and transfers
heat to the solar absorber tubes 630. Additional heat may be added
to the engine 544 exhaust flue gas by utilizing the burner 640 to
burn additional fuel. The flue gas contains sufficient oxygen to
allow combustion of the supplemental fuel 642.
[0152] If the engine 544 is not operating, the solar absorber can
still receive supplemental heat by operating the combustion air fan
648 to provide oxygen for combustion of the supplemental fuel 642.
If the engine 544 is not operating and it is necessary to operate
the combustion air fan, damper 650 is closed and damper 652 is
opened to prevent combustion air from flowing through the ductwork
backward toward the engine 544. If the engine 544 is running and it
is not necessary or desired to operate the combustion air fan 648,
the damper 652 will be in the closed position and damper 650 will
be in the open position. After passing through the solar absorber
612, the exhaust flue gas 654 is vented to atmosphere.
[0153] A pump 722 is used to circulate the heat transfer fluid
through the solar absorber and engine exhaust heat exchanger 720.
The fluid then flows to the organic rankine cycle boiler 724 where
it vaporizes the working fluid. The heat transfer fluid then flows
back to the circulating pump 722 to be re-circulated through the
system again.
[0154] A pump 730 is used to pump an organic rankine cycle working
fluid such as isopentane to the boiler 724 where it is vaporized.
The vapor then flows to the organic rankine cycle turbine 732 where
it expands and turns a shaft 734 which is connected to a generator
736 using coupling 738. The vapor passes through the turbine 732
and flows to an air cooled condenser 740 which condenses the vapor
into a liquid. The liquid flows back to the circulating pump 730
where it is pumped back to the boiler 724.
[0155] Referring now to FIG. 18, depicted therein is a process flow
diagram illustrating an example energy recovery system that may be
used with the heat energy recovery system of the example wind
turbine systems of the present invention. For illustration
purposes, the example energy recovery system shown in FIG. 18 is
the heat recovery system 554 of the example wind turbine system 520
described above.
[0156] The heat recovery system 554 utilizes a steam rankine cycle
heat recovery system. As generally discussed above, the system 520
utilizes the wind to turn the generator 534 to produce electricity,
solar energy from the sun to produce electricity using an steam
rankine cycle and an engine 544 to generate supplemental or
emergency power using conventional fossil fuels. The hot flue gas
from the engine 544 flows through a heat exchanger 750 where it
transfers heat to a circulating heat transfer fluid. The flue gas
then passes through an emission control device 670 and then to a
burner 640 before entering the solar absorber 612 where it passes
by and transfers heat to the solar absorber tubes 630.
[0157] Additional heat may be added to the engine 544 exhaust flue
gas by utilizing the burner 640 to burn additional fuel 642. The
flue gas contains sufficient oxygen to allow combustion of the
supplemental fuel 642. If the engine 544 is not operating, the
solar absorber 610 can still receive supplemental heat by operating
the combustion air fan 648 to provide oxygen for combustion of the
supplemental fuel 642. If the engine 544 is not operating and it is
necessary to operate the combustion air fan, damper 650 is closed
and damper 652 is opened to prevent combustion air from flowing
through the ductwork backward toward the engine 544. If the engine
544 is running and it is not necessary or desired to operate the
combustion air fan 648, the damper 650 will be in the open position
and damper 652 will be in the closed position. After passing
through the solar absorber 610, the exhaust flue gas 654 is vented
to atmosphere.
[0158] The steam rankine cycle in FIG. 18 utilizes a feedwater pump
752 to pump feedwater to a convection section 754 of the solar
absorber 610 and to the engine exhaust boiler 750. The feedwater
that flows to the convection section 754 of the solar absorber 612
picks up heat from the engine exhaust flue gas 654 before this gas
exits the convection section 754. The feedwater then flows through
the solar absorber tubes 630 where it is converted into steam and
then flows to a steam drum 770 for separation into steam and to
water. The steam flows out of the steam drum 770 to the steam
turbine 760 where it turns the turbine rotor and drives the
generator 764 through coupling 766 to generate electricity. Low
pressure steam exits the steam turbine 760 and flows to a surface
condenser 768 where it is condensed back to water and then flows to
the feedwater pump 752 for recirculation. Water that is separated
out in the steam drum 770 flows to a de-aerator 772 and back to the
boiler feedwater pump 752.
[0159] Feedwater that is pumped to the engine exhaust boiler 750 is
converted into steam and then flows to a steam drum 756 for
separation into steam and water. The steam flows out of the steam
drum 756 to the steam turbine 760 where it turns the turbine rotor
and drives the generator 764 through coupling 766 to generate
electricity. Low pressure steam exits the steam turbine 760 and
flows to a surface condenser 768 where it is condensed back to
water and then flows to the feedwater pump 752 for recirculation.
Water that is separated out in the steam drum 756 flows to a
deaerator 758 and back to the boiler feedwater pump 752.
[0160] While the present invention is illustrated by description of
several examples and while the illustrative examples are described
in detail, it is not the intention of the applicants to restrict or
in any way limit the scope of the appended claims to such detail.
Additional advantages and modifications within the scope of the
appended claims will readily appear to those sufficed in the art.
The invention in its broader aspects is therefore not limited to
the specific details, representative apparatus and methods, and
illustrative examples shown and described. Accordingly, departures
may be made from such details without departing from the spirit or
scope of applicants' general concept.
* * * * *