U.S. patent application number 14/686641 was filed with the patent office on 2015-10-08 for modular thermoelectric units for heat recovery systems and methods thereof.
The applicant listed for this patent is Alphabet Energy, Inc.. Invention is credited to Christopher Hannemann, Adam Lorimer, Matthew L. Scullin, Sravan Kumar R. Sura.
Application Number | 20150287902 14/686641 |
Document ID | / |
Family ID | 48796224 |
Filed Date | 2015-10-08 |
United States Patent
Application |
20150287902 |
Kind Code |
A1 |
Lorimer; Adam ; et
al. |
October 8, 2015 |
MODULAR THERMOELECTRIC UNITS FOR HEAT RECOVERY SYSTEMS AND METHODS
THEREOF
Abstract
Apparatus and method for generating electricity. The apparatus
includes one or more first components configured to extract heat
from at least a first fluid flow at a first temperature to one or
more devices configured to convert thermal energy to electric
energy. The first fluid flow is in a first direction. Additionally,
the apparatus includes one or more second components configured to
transfer heat from the one or more devices to at least a second
fluid flow at a second temperature. The second temperature is lower
than the first temperature, and the second fluid flow is in a
second direction. Each first part of the first fluid flow
corresponds to a first shortest distance to the one or more
devices, and the first shortest distance is less than half the
square root of the total free flow area for a corresponding first
cross-section of the first fluid flow.
Inventors: |
Lorimer; Adam; (Walnut
Creek, CA) ; Scullin; Matthew L.; (San Francisco,
CA) ; Sura; Sravan Kumar R.; (Fremont, CA) ;
Hannemann; Christopher; (Berkeley, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Alphabet Energy, Inc. |
Hayward |
CA |
US |
|
|
Family ID: |
48796224 |
Appl. No.: |
14/686641 |
Filed: |
April 14, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13749470 |
Jan 24, 2013 |
|
|
|
14686641 |
|
|
|
|
61590597 |
Jan 25, 2012 |
|
|
|
Current U.S.
Class: |
136/201 ;
136/205 |
Current CPC
Class: |
F28F 2250/106 20130101;
H01L 35/32 20130101; F28F 2009/029 20130101; F28F 2250/06 20130101;
H01L 35/30 20130101; F28F 9/0246 20130101; F28F 9/0253 20130101;
H01L 35/34 20130101 |
International
Class: |
H01L 35/32 20060101
H01L035/32; H01L 35/30 20060101 H01L035/30 |
Claims
1. An apparatus for generating electricity, the apparatus
comprising: one or more first components configured to extract heat
from at least a first fluid flow at a first temperature to one or
more devices configured to convert thermal energy to electric
energy, the first fluid flow being in a first direction; and one or
more second components configured to transfer heat from the one or
more devices to at least a second fluid flow at a second
temperature, the second temperature being lower than the first
temperature, the second fluid flow being in a second direction;
wherein: each first part of the first fluid flow corresponds to a
first shortest distance to the one or more devices, the first
shortest distance being less than half the square root of the total
free flow area for a corresponding first cross-section of the first
fluid flow, the first cross-section being perpendicular to the
first direction; and each second part of the second fluid flow
corresponds to a second shortest distance to the one or more
devices, the second shortest distance being less than half the
square root of the total free flow area for a corresponding second
cross-section of the second fluid flow, the second cross-section
being perpendicular to the second direction.
2. The apparatus of claim 1 wherein the first direction varies with
movement of the first fluid flow.
3. The apparatus of claim 1 wherein the first direction is fixed
regardless of movement of the first fluid flow.
4. The apparatus of claim 1 wherein the second direction varies
with movement of the second fluid flow.
5. The apparatus of claim 1 wherein the second direction is fixed
regardless of movement of the second fluid flow.
6. The apparatus of claim 1 wherein: the one or more first
components include a first heat exchanger; and the one or more
second components include a second heat exchanger.
7. The apparatus of claim 1 wherein the one or more devices are one
or more thermoelectric devices.
8. The apparatus of claim 7 wherein each of the one or more
thermoelectric devices includes at least one thermoelectric
material.
9. A thermoelectric apparatus, the apparatus comprising: one or
more first channels configured to receive one or more first parts
of a first fluid flow at a first temperature; one or more second
channels configured to receive one or more parts of a second fluid
flow at a second temperature, the second temperature being lower
than the first temperature; one or more third channels configured
to receive one or more second parts of the first fluid flow, the
one or more third channels being separated from the one or more
first channels by at least the one or more second channels; one or
more first thermoelectric materials located between the one or more
first channels and the one or more second channels; and one or more
second thermoelectric materials located between the one or more
second channels and the one or more third channels.
10. The thermoelectric apparatus of claim 9 wherein: the one or
more first channels are one or more parts of a first heat
exchanger; the one or more second channels are one or more parts of
a second heat exchanger; and the one or more third channels are one
or more parts of a third heat exchanger; wherein the first heat
exchanger and the third heat exchanger are separated by at least
the second heat exchanger.
11. The thermoelectric apparatus of claim 10 wherein: the one or
more first thermoelectric materials are located between the first
heat exchanger and the second heat exchanger; and the one or more
second thermoelectric materials are located between the second heat
exchanger and the third heat exchanger.
12. The thermoelectric apparatus of claim 9 wherein: the one or
more first channels are one or more parts of a first heat
exchanger; the one or more second channels include multiple
channels, at least one of the multiple channels being at least a
part of a second heat exchanger, at least another one of the
multiple channels being at least a part of a third heat exchanger;
and the one or more third channels are one or more parts of a
fourth heat exchanger.
13. The thermoelectric apparatus of claim 12 wherein the first heat
exchanger and the fourth heat exchanger are separated by at least
the second heat exchanger and the third heat exchanger.
14. The thermoelectric apparatus of claim 12 wherein the second
heat exchanger and the third heat exchanger are in contact with
each other.
15. The thermoelectric apparatus of claim 12 wherein: the first
heat exchanger and the second heat exchanger are parts of a first
modular thermoelectric unit; and the third heat exchanger and the
fourth heat exchanger are parts of a second modular thermoelectric
unit.
16. The thermoelectric apparatus of claim 12 wherein: the one or
more first thermoelectric materials are located between the first
heat exchanger and the second heat exchanger; and the one or more
second thermoelectric materials are located between the third heat
exchanger and the fourth heat exchanger.
17. The thermoelectric apparatus of claim 9 wherein: the one or
more first thermoelectric materials are not in direct contact with
the one or more first channels or the one or more second channels;
and the one or more second thermoelectric materials are not in
direct contact with the one or more second channels or the one or
more third channels.
18. The thermoelectric apparatus of claim 9 wherein the one or more
second channels are further configured to receive all parts of the
second fluid flow.
19.-27. (canceled)
28. A thermoelectric apparatus, the apparatus comprising: a first
heat exchanger configured to transfer heat to or extract heat from
a first fluid flow at a first temperature; a second heat exchanger
configured to extract heat from or transfer heat to a second fluid
flow at a second temperature, the second temperature being
different from the first temperature; a third heat exchanger
configured to transfer heat to or extract heat from a third fluid
flow at the first temperature, the third heat exchanger being
separated from the first heat exchanger by at least the second heat
exchanger; one or more first thermoelectric materials sandwiched
between the first heat exchanger and the second heat exchanger; one
or more second thermoelectric materials sandwiched between the
second heat exchanger and the third heat exchanger; and one or more
components extending from the first heat exchanger to the third
heat exchanger without making any thermal contact with the second
heat exchanger; wherein: the one or more first thermoelectric
materials, the second heat exchanger, and the one or more second
thermoelectric materials are located between the first heat
exchanger and the third heat exchanger; and the one or more
components are configured to apply one or more compressive forces
to at least the one or more first thermoelectric materials, the
second heat exchanger, and the one or more second thermoelectric
materials.
29. The thermoelectric apparatus of claim 28 wherein the one or
more components are not in any thermal contact with the one or more
first thermoelectric materials and are not in any thermal contact
with the one or more second thermoelectric materials.
30. The thermoelectric apparatus of claim 28 wherein the second
temperature is higher than the first temperature.
31. The thermoelectric apparatus of claim 28 wherein the second
temperature is lower than the first temperature.
32. The thermoelectric apparatus of claim 28 wherein: the one or
more first thermoelectric materials are not in direct contact with
the first heat exchanger or the second heat exchanger; and the one
or more second thermoelectric materials are not in direct contact
with the second heat exchanger or the third heat exchanger.
33. The thermoelectric apparatus of claim 28 wherein the one or
more components include one or more bolts extending from the first
heat exchanger to the third heat exchanger without making any
thermal contact with the second heat exchanger.
34. A method for generating electricity, the method comprising:
extracting heat from at least a first fluid flow at a first
temperature to one or more devices configured to convert thermal
energy to electric energy, the first fluid flow being in a first
direction; and transferring heat to at least a second fluid flow at
a second temperature, the second temperature being lower than the
first temperature, the second fluid flow being in a second
direction; wherein: each first part of the first fluid flow
corresponds to a first shortest distance to the one or more
devices, the first shortest distance being less than half the
square root of the total free flow area for a corresponding first
cross-section of the first fluid flow, the first cross-section
being perpendicular to the first direction; and each second part of
the second fluid flow corresponds to a second shortest distance to
the one or more devices, the second shortest distance being less
than half the square root of the total free flow area for a
corresponding second cross-section of the second fluid flow, the
second cross-section being perpendicular to the second
direction.
35. The method of claim 34 wherein the one or more devices are one
or more thermoelectric devices.
36. A thermoelectric method for generating electricity, the method
comprising: receiving, by one or more first channels, one or more
first parts of a first fluid flow at a first temperature;
receiving, by one or more second channels, one or more parts of a
second fluid flow at a second temperature, the second temperature
being lower than the first temperature; receiving, by one or more
third channels, one or more second parts of the first fluid flow,
the one or more third channels being separated from the one or more
first channels by at least the one or more second channels; and
generating electricity by at least one or more first thermoelectric
materials and one or more second thermoelectric materials, the one
or more first thermoelectric materials located between the one or
more first channels and the one or more second channels, the one or
more second thermoelectric materials located between the one or
more second channels and the one or more third channels.
37. (canceled)
38. A method for thermoelectric conversion, the method comprising:
transferring heat to or extracting heat from a first fluid flow at
a first temperature by a first heat exchanger; extracting heat from
or transferring heat to a second fluid flow at a second temperature
by a second heat exchanger, the second temperature being different
from the first temperature; transferring heat to or extracting heat
from a third fluid flow at the first temperature by a third heat
exchanger, the third heat exchanger being separated from the first
heat exchanger by at least the second heat exchanger; and applying,
by one or more components, one or more compressive forces to at
least one or more first thermoelectric materials, the second heat
exchanger, and one or more second thermoelectric materials, the one
or more first thermoelectric materials sandwiched between the first
heat exchanger and the second heat exchanger, the one or more
second thermoelectric materials sandwiched between the second heat
exchanger and the third heat exchanger, the one or more first
thermoelectric materials, the second heat exchanger, and the one or
more second thermoelectric materials being located between the
first heat exchanger and the third heat exchanger; wherein the
process for applying, by one or more components, one or more
compressive forces includes extending the one or more components
from the first heat exchanger to the third heat exchanger without
making any thermal contact with the second heat exchanger.
39. The method of claim 38 wherein the process for applying, by one
or more components, one or more compressive forces includes
extending the one or more components from the first heat exchanger
to the third heat exchanger without making any thermal contact with
the one or more first thermoelectric materials and without making
any thermal contact with the one or more second thermoelectric
materials.
40. The method of claim 38 wherein the one or more components
include one or more bolts.
Description
1. CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/590,597, filed Jan. 25, 2012, commonly assigned
and incorporated by reference herein for all purposes.
2. BACKGROUND OF THE INVENTION
[0002] The present invention is directed to conversion between heat
and electricity. More particularly, the invention provides systems
and methods for recovery of waste heat. Merely by way of example,
the invention has been applied to a modular thermoelectric unit
that can be easily assembled and scaled up to an optimal sized
system for providing solutions for various heat recovery
applications including industrial combustion processes with
enhanced power output, reduced parasitic power losses, and lowered
manufacture cost. However, it would be recognized that the
invention has a much broader range of applicability.
[0003] Any process that consumes energy usually is not 100%
efficient and often generates waste energy, usually in the form of
heat. For example, the industrial combustion process generates a
substantial amount of waste heat via an exhaust gas flow at high
temperature. In order to improve the efficiency of the combustion
process, effectively capturing and converting some of this waste
heat into a useful form without disturbing the primary operation
would be desired. A conventional technique that has been considered
is to place thermoelectric (TE) devices onto the exhaust system
associated with the combustion process.
[0004] The thermoelectric devices are made from thermoelectric
materials that can convert an appreciable amount of thermal energy
into electricity in an applied temperature gradient (e.g., the
Seebeck effect) or pump heat in an applied electric field (e.g.,
the Peltier effect). Interest in the use of thermoelectric devices
that comprise thermoelectric materials has grown in recent years
partly due to the heightened need for systems that recover waste
heat as electricity to improve energy efficiency in the industrial
combustion process.
[0005] To date, thermoelectrics have had limited commercial
applicability often due to poor cost effectiveness and low
conversion performance in comparison with other technologies that
accomplish similar energy generation or refrigeration. Where there
are almost no other technologies as suitable as thermoelectrics for
lightweight and low footprint applications, thermoelectrics have
nonetheless been limited by their high costs in thermoelectric
materials and the manufacture of high-performance thermoelectric
devices. The thermoelectric materials in conventional
thermoelectric modules are generally comprised of bismuth telluride
or lead telluride, which are toxic, difficult to manufacture with,
and expensive to procure and process.
[0006] More recently, advances in developing and manufacturing
nano-structured materials with enhanced thermoelectric performance
have been initiated. In particular, the thermoelectric performance
of the nano-structured material is characterized by, e.g., high
efficiency, high power density, or high "thermoelectric figure of
merit" ZT (where ZT is equal to S.sup.2 .sigma./k, and S is the
Seebeck coefficient, .sigma. is the electrical conductivity, and k
is the thermal conductivity). This technical development drives a
need for devices and/or systems in both alternative energy
production and microelectronics that usually requires high
manufacturability and low cost. This technical development also
drives the need for converting waste heat in exhaust from many
industrial systems, such as industrial combustion process, into
useful electrical power.
[0007] FIG. 1 is a simplified diagram showing a conventional heat
recovery system using one or more thermoelectric device components
for generating power from a waste heat source. As shown, in a
conventional heat recovery system 4000 (e.g., a conventional
thermoelectric generation system), one or more thermoelectric (TE)
device components 4010 are attached on one side to a hot plate 4020
of a hot-side heat exchanger 4022 and leave the other side
subjecting to one or more cold fluid flows 4030 (e.g., one or more
cold air flows, one or more cold gas flows). As shown, the one or
more thermoelectric device components 4010 are disposed entirely
outside the main hot flow region 4040. The hot plate 4020 is
thermally connected to an extended conductor 4024 with multiple
fins 4026 sticking into the hot flow region 4040. For example, one
or more hot fluid flows 4042 (e.g., one or more hot air flows, one
or more hot gas flows) move out of an exhaust pipe or a chimney
4044, and the extended conductor 4024 and the multiple fins 4026
serve as an indirect thermal energy collector. But such indirect
thermal energy collector often is quite inefficient in utilizing
the one or more hot fluid flows 4042 of the waste heat.
[0008] To take advantage of the high-temperature thermoelectric
devices and flexibly apply these devices for various industrial
combustion processes without disturbing the operation of the
primary process, it is highly desirable to make an improved
thermoelectric system for enhanced power output, lowered parasitic
power loss, and reduced cost.
3. BRIEF SUMMARY OF THE INVENTION
[0009] The present invention is directed to conversion between heat
and electricity. More particularly, the invention provides systems
and methods for recovery of waste heat. Merely by way of example,
the invention has been applied to a modular thermoelectric unit
that can be easily assembled and scaled up to an optimal sized
system for providing solutions for various heat recovery
applications including industrial combustion processes with
enhanced power output, reduced parasitic power losses, and lowered
manufacture cost. However, it would be recognized that the
invention has a much broader range of applicability.
[0010] According to one embodiment, an apparatus for generating
electricity includes one or more first components configured to
extract heat from at least a first fluid flow at a first
temperature to one or more devices configured to convert thermal
energy to electric energy. The first fluid flow is in a first
direction. Additionally, the apparatus includes one or more second
components configured to transfer heat from the one or more devices
to at least a second fluid flow at a second temperature. The second
temperature is lower than the first temperature, and the second
fluid flow is in a second direction. Each first part of the first
fluid flow corresponds to a first shortest distance to the one or
more devices, and the first shortest distance is less than half the
square root of the total free flow area for a corresponding first
cross-section of the first fluid flow. The first cross-section is
perpendicular to the first direction. Each second part of the
second fluid flow corresponds to a second shortest distance to the
one or more devices, and the second shortest distance is less than
half the square root of the total free flow area for a
corresponding second cross-section of the second fluid flow. The
second cross-section is perpendicular to the second direction.
[0011] According to another embodiment, a thermoelectric apparatus
includes one or more first channels configured to receive one or
more first parts of a first fluid flow at a first temperature, and
one or more second channels configured to receive one or more parts
of a second fluid flow at a second temperature. The second
temperature is lower than the first temperature. Additionally, the
apparatus includes one or more third channels configured to receive
one or more second parts of the first fluid flow, and the one or
more third channels are separated from the one or more first
channels by at least the one or more second channels. Moreover, the
apparatus includes one or more first thermoelectric materials
located between the one or more first channels and the one or more
second channels, and one or more second thermoelectric materials
located between the one or more second channels and the one or more
third channels.
[0012] According to yet another embodiment, a heat recovery system
includes a thermoelectric apparatus, a first duct coupled to the
thermoelectric apparatus, and a second duct not coupled to the
thermoelectric apparatus. The first duct and the second duct both
are connected to a third duct and configured to receive by the
first duct a first fluid flow at a first temperature from the third
duct if the second duct does not receive the first fluid flow and
to receive by the second duct the first fluid flow from the third
duct if the first duct does not receive the first fluid flow. The
thermoelectric apparatus is configured to receive at least a second
fluid flow at a second temperature. The second fluid flow moves
into the thermoelectric apparatus from one or more first perimeter
parts of the thermoelectric apparatus in a first direction. The
first direction is towards the second duct, and the second
temperature is lower than the first temperature. Also, the
thermoelectric apparatus is configured to discharge the second
fluid flow into a fourth duct, and the fourth duct is the second
duct or is substantially parallel with the second duct.
[0013] According to yet another embodiment, a thermoelectric
apparatus includes a first heat exchanger configured to transfer
heat to or extract heat from a first fluid flow at a first
temperature, and a second heat exchanger configured to extract heat
from or transfer heat to a second fluid flow at a second
temperature. The second temperature is different from the first
temperature. Additionally, the apparatus includes a third heat
exchanger configured to transfer heat to or extract heat from a
third fluid flow at the first temperature, and the third heat
exchanger is separated from the first heat exchanger by at least
the second heat exchanger. Moreover, the apparatus includes one or
more first thermoelectric materials sandwiched between the first
heat exchanger and the second heat exchanger, one or more second
thermoelectric materials sandwiched between the second heat
exchanger and the third heat exchanger, and one or more components
extending from the first heat exchanger to the third heat exchanger
without making any thermal contact with the second heat exchanger.
The one or more first thermoelectric materials, the second heat
exchanger, and the one or more second thermoelectric materials are
located between the first heat exchanger and the third heat
exchanger, and the one or more components are configured to apply
one or more compressive forces to at least the one or more first
thermoelectric materials, the second heat exchanger, and the one or
more second thermoelectric materials.
[0014] According to yet another embodiment, a method for generating
electricity includes extracting heat from at least a first fluid
flow at a first temperature to one or more devices configured to
convert thermal energy to electric energy. The first fluid flow is
in a first direction. Additionally, the method includes
transferring heat to at least a second fluid flow at a second
temperature. The second temperature is lower than the first
temperature, and the second fluid flow is in a second direction.
Each first part of the first fluid flow corresponds to a first
shortest distance to the one or more devices, and the first
shortest distance is less than half the square root of the total
free flow area for a corresponding first cross-section of the first
fluid flow. The first cross-section is perpendicular to the first
direction. Each second part of the second fluid flow corresponds to
a second shortest distance to the one or more devices, and the
second shortest distance is less than half the square root of the
total free flow area for a corresponding second cross-section of
the second fluid flow. The second cross-section is perpendicular to
the second direction.
[0015] According to yet another embodiment, a thermoelectric method
for generating electricity includes receiving, by one or more first
channels, one or more first parts of a first fluid flow at a first
temperature, and receiving, by one or more second channels, one or
more parts of a second fluid flow at a second temperature. The
second temperature is lower than the first temperature.
Additionally, the method includes receiving, by one or more third
channels, one or more second parts of the first fluid flow. The one
or more third channels are separated from the one or more first
channels by at least the one or more second channels. Moreover, the
method includes generating electricity by at least one or more
first thermoelectric materials and one or more second
thermoelectric materials. The one or more first thermoelectric
materials are located between the one or more first channels and
the one or more second channels, and the one or more second
thermoelectric materials are located between the one or more second
channels and the one or more third channels.
[0016] According to yet another embodiment, a method for heat
recovery includes receiving, by a first duct, a first fluid flow at
a first temperature from a third duct connected to both the first
duct and a second duct if the second duct does not receive the
first fluid flow. The first duct is coupled to a thermoelectric
apparatus, and the second duct is not coupled to the thermoelectric
apparatus. Additionally, the method includes receiving, by the
second duct, the first fluid flow from the third duct if the first
duct does not receive the first fluid flow. Moreover, the method
includes receiving, by the thermoelectric apparatus, at least a
second fluid flow at a second temperature, and the second fluid
flow moves into the thermoelectric apparatus from one or more first
perimeter parts of the thermoelectric apparatus in a first
direction. The first direction is towards the second duct, and the
second temperature is lower than the first temperature. Also, the
method includes discharging, by the thermoelectric apparatus, the
second fluid flow into a fourth duct. The fourth duct is the second
duct or is substantially parallel with the second duct.
[0017] According to yet another embodiment, a method for
thermoelectric conversion includes transferring heat to or
extracting heat from a first fluid flow at a first temperature by a
first heat exchanger, and extracting heat from or transferring heat
to a second fluid flow at a second temperature by a second heat
exchanger. The second temperature is different from the first
temperature. Additionally, the method includes transferring heat to
or extracting heat from a third fluid flow at the first temperature
by a third heat exchanger, and the third heat exchanger is
separated from the first heat exchanger by at least the second heat
exchanger. Moreover, the method includes applying, by one or more
components, one or more compressive forces to at least one or more
first thermoelectric materials, the second heat exchanger, and one
or more second thermoelectric materials. The one or more first
thermoelectric materials are sandwiched between the first heat
exchanger and the second heat exchanger, and the one or more second
thermoelectric materials are sandwiched between the second heat
exchanger and the third heat exchanger. The one or more first
thermoelectric materials, the second heat exchanger, and the one or
more second thermoelectric materials are located between the first
heat exchanger and the third heat exchanger. The process for
applying, by one or more components, one or more compressive forces
includes extending the one or more components from the first heat
exchanger to the third heat exchanger without making any thermal
contact with the second heat exchanger.
[0018] Depending upon the embodiment, one or more benefits may be
achieved. These benefits and various additional objects, features,
and advantages of the present invention can be fully appreciated
with reference to the detailed description and accompanying
drawings that follow.
4. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a simplified diagram showing a conventional heat
recovery system using one or more thermoelectric device components
for generating power from a waste heat source.
[0020] FIG. 2A is a simplified diagram showing a conventional
modular thermoelectric unit.
[0021] FIGS. 2B-2C are simplified diagrams showing a modular
thermoelectric unit according to certain embodiments of the present
invention.
[0022] FIGS. 3A-3B are simplified diagrams showing a modular
thermoelectric unit according to some embodiments of the present
invention.
[0023] FIG. 4A is a simplified diagram showing a conventional
modular thermoelectric unit.
[0024] FIG. 4B is a simplified diagram showing a modular
thermoelectric unit according to certain embodiments of the present
invention.
[0025] FIGS. 5A-5B are simplified diagrams showing fluid flows in a
cold sink component and a heat source component as parts of a
conventional modular thermoelectric unit as shown in FIG. 2A and/or
FIG. 4A.
[0026] FIGS. 5C-5D are simplified diagrams showing fluid flows in a
cold sink component and a heat source component as parts of a
modular thermoelectric unit as shown in FIGS. 2B-2C, FIGS. 3A-3B,
and/or FIG. 4B according to some embodiments of the present
invention.
[0027] FIGS. 6A-6D are simplified diagrams showing various views of
a modular thermoelectric unit according to one embodiment of the
present invention.
[0028] FIG. 7 is a simplified diagram showing certain components of
the modular thermoelectric unit as shown in FIGS. 6A-6D according
to one embodiment of the present invention.
[0029] FIG. 8A is a simplified diagram showing some components of
the modular thermoelectric unit as shown in FIGS. 6A-6D according
to another embodiment of the present invention.
[0030] FIG. 8B is a simplified diagram showing some components of
the modular thermoelectric unit as shown in FIGS. 6A-6D according
to yet another embodiment of the present invention.
[0031] FIG. 9 is a simplified diagram showing certain components of
the modular thermoelectric unit as shown in FIGS. 6A-6D according
to yet another embodiment of the present invention.
[0032] FIG. 10 is a simplified diagram showing a modular
thermoelectric subsystem according to one embodiment of the present
invention.
[0033] FIGS. 11A-11B are simplified diagrams showing a modular
thermoelectric subsystem according to another embodiment of the
present invention.
[0034] FIG. 12 is a simplified diagram showing a thermoelectric
system according to one embodiment of the present invention.
[0035] FIGS. 13A-13B are simplified diagrams showing a heat
recovery system including the thermoelectric system according to
one embodiment of the present invention.
[0036] FIG. 14 is a simplified diagram showing a thermoelectric
system according to another embodiment of the present
invention.
[0037] FIGS. 15A-15B are simplified diagrams showing a heat
recovery system including the thermoelectric system 1300 according
to another embodiment of the present invention.
[0038] FIGS. 16A-16B are simplified diagrams showing a heat
recovery system including the thermoelectric system 1300 according
to yet another embodiment of the present invention.
[0039] FIGS. 17A-17B are simplified diagrams showing the bypass
duct and the supply ducts as parts of a heat recovery system
including the thermoelectric system according to yet another
embodiment of the present invention.
[0040] FIG. 18 is a simplified diagram showing a heat recovery
system as shown in FIGS. 13A-13B, FIGS. 15A-15B, FIGS. 16A-16B,
and/or FIGS. 17A-17B according to some embodiments of the present
invention.
5. DETAILED DESCRIPTION OF THE INVENTION
[0041] The present invention is directed to conversion between heat
and electricity. More particularly, the invention provides systems
and methods for recovery of waste heat. Merely by way of example,
the invention has been applied to a modular thermoelectric unit
that can be easily assembled and scaled up to an optimal sized
system for providing solutions for various heat recovery
applications including industrial combustion processes with
enhanced power output, reduced parasitic power losses, and lowered
manufacture cost. However, it would be recognized that the
invention has a much broader range of applicability.
[0042] FIG. 2A is a simplified diagram showing a conventional
modular thermoelectric unit. As shown in FIG. 2A, a modular
thermoelectric unit 110 includes a cold sink component 112 (e.g., a
cold-side heat exchanger), a heat source component 116 (e.g., a
hot-side heat exchanger), and a thermoelectric device component
114. For example, the thermoelectric device component 114 is
sandwiched between the cold sink component 112 and the heat source
component 116. In another example, the thermoelectric device
component 114 forms a cold junction with the cold sink component
112, and forms a hot junction with the heat source component
116.
[0043] In one embodiment, the cold sink component 112 serves as a
low temperature source for the thermoelectric device component 114,
and the heat source component 116 serves as a high temperature
source for the thermoelectric device component 114. In another
embodiment, the thermoelectric device component 114 can convert
thermal energy into electricity in response to the temperature
gradient between the cold junction and the hot junction.
[0044] FIGS. 2B-2C are simplified diagrams showing a modular
thermoelectric unit according to certain embodiments of the present
invention. These diagrams are merely examples, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications.
[0045] As shown in FIG. 2B, a modular thermoelectric unit 120
includes thermoelectric unit components 122, 124, and 126. For
example, each of the thermoelectric unit components 122, 124, and
126 includes a cold sink component (e.g., a cold-side heat
exchanger), a heat source component (e.g., a hot-side heat
exchanger), and a thermoelectric device component sandwiched
between the cold sink component and the heat source component. In
another example, the modular thermoelectric unit 120 is formed by
stacking the thermoelectric unit components 122, 124, and 126
together.
[0046] According to one embodiment, the heat source component of
the thermoelectric unit component 122 is in contact with the heat
source component of the thermoelectric unit component 124, and the
cold sink component of the thermoelectric unit component 124 is in
contact with the cold sink component of the thermoelectric unit
component 126. According to another embodiment, a plurality of
modular thermoelectric units 120 are assembled together by
attaching a cold sink component of a modular thermoelectric unit
120 to a cold sink component of another modular thermoelectric unit
120, and/or by attaching a heat source component of a modular
thermoelectric unit 120 to a heat source component of another
modular thermoelectric unit 120.
[0047] As shown in FIG. 2C, a modular thermoelectric unit 130
includes cold sink components 132, 134 and 136 (e.g., three
cold-side heat exchangers), thermoelectric device components 142,
144, 146, 148 and 150, and heat source components 152, 154 and 156
(e.g., three hot-side heat exchangers). For example, the
thermoelectric device component 142 is sandwiched between the cold
sink component 132 and the heat source component 152, the
thermoelectric device component 144 is sandwiched between the heat
source component 152 and the cold sink component 134, the
thermoelectric device component 146 is sandwiched between the cold
sink component 134 and the heat source component 154, the
thermoelectric device component 148 is sandwiched between the heat
source component 154 and the cold sink component 136, and the
thermoelectric device component 150 is sandwiched between the cold
sink component 136 and the heat source component 156. In another
example, each of the heat source components 152 and 154 form two
hot junctions with its two neighboring thermoelectric device
components, and each of the cold sink components 134 and 136 form
two cold junctions with its two neighboring thermoelectric device
components. According to one embodiment, a plurality of modular
thermoelectric units 130 are assembled together by attaching a cold
sink component of a modular thermoelectric unit 130 to a cold sink
component of another modular thermoelectric unit 130, and/or by
attaching a heat source component of a modular thermoelectric unit
130 to a heat source component of another modular thermoelectric
unit 130.
[0048] FIGS. 3A-3B are simplified diagrams showing a modular
thermoelectric unit according to some embodiments of the present
invention. These diagrams are merely examples, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications.
[0049] As shown in FIG. 3A, a modular thermoelectric unit 210
includes heat source components 212 and 214 (e.g., two hot-side
heat exchangers), a cold sink component 216 (e.g., a cold-side heat
exchanger), and thermoelectric device components 224 and 226. For
example, the thermoelectric device component 224 is sandwiched
between the heat source component 212 and the cold sink component
216, and the thermoelectric device component 226 is sandwiched
between the cold sink component 216 and the heat source component
214. In another example, the cold sink component 216 is sandwiched
between the thermoelectric device components 224 and 226.
[0050] According to one embodiment, the modular thermoelectric unit
210 includes two hot junctions formed between the heat source
component 212 and the thermoelectric device component 224 and
formed between the heat source component 214 and the thermoelectric
device component 226. According to another embodiment, the modular
thermoelectric unit 210 includes two cold junctions formed between
the heat source component 216 and the thermoelectric device
component 224 and formed between the heat source component 216 and
the thermoelectric device component 226.
[0051] As shown in FIG. 3B, a modular thermoelectric unit 230
includes thermoelectric unit components 232 and 234. For example,
each of the thermoelectric unit components 232 and 234 includes two
heat source components (e.g., two hot-side heat exchangers), one
cold sink component (e.g., one cold-side heat exchanger), and two
thermoelectric device components, wherein one of the two
thermoelectric device component is sandwiched between one of the
two heat source components and the cold sink component, the other
one of the two thermoelectric device components is sandwiched
between the cold sink component and the other one of the two heat
source components, and the cold sink component is sandwiched
between the two thermoelectric device components. In another
example, the modular thermoelectric unit 230 is formed by stacking
the thermoelectric unit components 232 and 234 together.
[0052] According to one embodiment, the heat source component of
the thermoelectric unit component 232 is in contact with the heat
source component of the thermoelectric unit component 234.
According to one embodiment, a plurality of modular thermoelectric
units 230 are assembled together by attaching a heat source of a
modular thermoelectric unit 230 to a heat source of another modular
thermoelectric unit 230.
[0053] FIG. 4A is a simplified diagram showing a conventional
modular thermoelectric unit. As shown in FIG. 4A, a modular
thermoelectric unit 310 includes cold sink components 312 and 314
(e.g., two cold-side heat exchangers), a heat source component 316
(e.g., a hot-side heat exchanger), and thermoelectric device
components 324 and 326. For example, the thermoelectric device
component 324 is sandwiched between the cold sink component 312 and
the heat source component 316, and the thermoelectric device
component 326 is sandwiched between the heat source component 316
and the cold sink component 314. In another example, the heat
source component 316 is sandwiched between the thermoelectric
device components 324 and 326.
[0054] According to one embodiment, the modular thermoelectric unit
310 includes two cold junctions formed between the cold sink
component 312 and the thermoelectric device component 324 and
formed between the cold sink component 314 and the thermoelectric
device component 326. According to another embodiment, the modular
thermoelectric unit 310 includes two hot junctions formed between
the heat source component 316 and the thermoelectric device
component 324 and formed between the heat source component 316 and
the thermoelectric device component 326.
[0055] FIG. 4B is a simplified diagram showing a modular
thermoelectric unit according to certain embodiments of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications.
[0056] As shown in FIG. 4B, a modular thermoelectric unit 330
includes thermoelectric unit components 332 and 334. For example,
each of the thermoelectric unit components 332 and 334 includes two
cold sink components (e.g., two cold-side heat exchangers), one
heat source component (e.g., a hot-side heat exchanger), and two
thermoelectric device components, wherein one of the two
thermoelectric device components is sandwiched between one of the
two cold sink components and the heat source component, the other
one of the two thermoelectric device components is sandwiched
between the heat source component and the other one of the two cold
sink components, and the heat source component is sandwiched
between the two thermoelectric device components. In another
example, the modular thermoelectric unit 330 is formed by stacking
the thermoelectric unit components 332 and 334 together.
[0057] According to one embodiment, the cold sink component of the
thermoelectric unit component 332 is in contact with the cold sink
component of the thermoelectric unit component 334. According to
another embodiment, a plurality of modular thermoelectric units 330
are assembled together by attaching a cold sink of a modular
thermoelectric unit 330 to a cold sink of another modular
thermoelectric unit 330.
[0058] FIGS. 5A-5B are simplified diagrams showing fluid flows in a
cold sink component and a heat source component as parts of a
conventional modular thermoelectric unit as shown in FIG. 2A and/or
FIG. 4A.
[0059] As shown in FIG. 5A, the arrow 6410 represents the fluid
flow in a heat source component of the modular thermoelectric unit
110 as shown in FIG. 2A and/or the modular thermoelectric unit 310
as shown in FIG. 4A. Also as shown in FIG. 5A, the arrow 6420
represents the fluid flow in a cold sink component of the modular
thermoelectric unit 110 as shown in FIG. 2A and/or the modular
thermoelectric unit 310 as shown in FIG. 4A. For example, the fluid
flow in the heat source component and the fluid flow in the cold
sink component are in opposite directions. In another example, the
fluid flow in the heat source component and the fluid flow in the
cold sink component provide a temperature gradient between the hot
junction and the cold junction that varies in one dimension.
[0060] As shown in FIG. 5B, the arrow 6412 represents the fluid
flow in a heat source component of the modular thermoelectric unit
110 as shown in FIG. 2A and/or the modular thermoelectric unit 310
as shown in FIG. 4A. Also as shown in FIG. 5B, the dot 6422
represents the fluid flow in a cold sink component of the modular
thermoelectric unit 110 as shown in FIG. 2A and/or the modular
thermoelectric unit 310 as shown in FIG. 4A. For example, the fluid
flow in the heat source component and the fluid flow in the cold
sink component are in directions perpendicular to each other. In
another example, the fluid flow in the heat source component and
the fluid flow in the cold sink component provide a temperature
gradient between the hot junction and the cold junction that varies
in two dimensions, and a convenient spatial configuration for
disposing one or more cooling fans and/or pumps, and/or one or more
exhaust fans and/or pumps in order to control and drive the fluid
flows.
[0061] FIGS. 5C-5D are simplified diagrams showing fluid flows in a
cold sink component and a heat source component as parts of a
modular thermoelectric unit as shown in FIGS. 2B-2C, FIGS. 3A-3B,
and/or FIG. 4B according to some embodiments of the present
invention. These diagrams are merely examples, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications.
[0062] As shown in FIG. 5C, the arrow 410 represents the fluid flow
in a heat source component of the modular thermoelectric unit 120
as shown in FIG. 2B, the modular thermoelectric unit 130 as shown
in FIG. 2C, the modular thermoelectric unit 210 as shown in FIG.
3A, the modular thermoelectric unit 230 as shown in FIG. 3B, and/or
the modular thermoelectric unit 330 as shown in FIG. 4B. Also as
shown in FIG. 5C, the arrow 420 represents the fluid flow in a cold
sink component of the modular thermoelectric unit 120 as shown in
FIG. 2B, the modular thermoelectric unit 130 as shown in FIG. 2C,
the modular thermoelectric unit 210 as shown in FIG. 3A, the
modular thermoelectric unit 230 as shown in FIG. 3B, and/or the
modular thermoelectric unit 330 as shown in FIG. 4B. For example,
the fluid flow in the heat source component and the fluid flow in
the cold sink component are in opposite directions. In another
example, the fluid flow in the heat source component and the fluid
flow in the cold sink component provide a temperature gradient
between the hot junction and the cold junction that varies in one
dimension.
[0063] As shown in FIG. 5D, the arrow 412 represents the fluid flow
in a heat source component of the modular thermoelectric unit 120
as shown in FIG. 2B, the modular thermoelectric unit 130 as shown
in FIG. 2C, the modular thermoelectric unit 210 as shown in FIG.
3A, the modular thermoelectric unit 230 as shown in FIG. 3B, and/or
the modular thermoelectric unit 330 as shown in FIG. 4B. Also as
shown in FIG. 5D, the dot 422 represents the fluid flow in a cold
sink component of the modular thermoelectric unit 120 as shown in
FIG. 2B, the modular thermoelectric unit 130 as shown in FIG. 2C,
the modular thermoelectric unit 210 as shown in FIG. 3A, the
modular thermoelectric unit 230 as shown in FIG. 3B, and/or the
modular thermoelectric unit 330 as shown in FIG. 4B. For example,
the fluid flow in the heat source component and the fluid flow in
the cold sink component are in directions perpendicular to each
other. In another example, the fluid flow in the heat source
component and the fluid flow in the cold sink component provide a
temperature gradient between the hot junction and the cold junction
that varies in two dimensions, and a convenient spatial
configuration for disposing one or more cooling fans and/or pumps,
and/or one or more exhaust fans and/or pumps in order to control
and drive the fluid flows.
[0064] As discussed above and further emphasized here, FIGS. 2B-2C,
FIGS. 3A-3B, and FIG. 4B are merely examples, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications. For example, the modular thermoelectric unit (e.g.,
the modular thermoelectric unit 120, 130, 210, 230, or 330) has a
cuboid outline shape including at least one cold sink component,
one heat source component, and a thermoelectric (TE) device
component sandwiched between the heat source component and the cold
sink component. In another example, although the cuboid outline
shape is chosen for easy manufacture and assembly, other
geometrical shapes can also be used depending on embodiments and
system requirements for customized applications.
[0065] According to one embodiment, the heat source component
includes a heat exchanger that utilizes thermal energy from a hot
fluid flow of an existing industrial exhaust to form a hot side
contacted with a hot terminal of the thermoelectric device
component. According to another embodiment, the cold sink includes
another heat exchanger that utilizes a natural and/or forced,
ambient and/or supplied cold fluid flow to form a cold side
contacted with a cold terminal of the thermoelectric device
component. The hot junction and/or the cold junction is configured
to maintain a temperature gradient for producing electrical power
by the thermoelectric device component, thereby achieving the goal
for recovering heat which is otherwise wasted.
[0066] FIGS. 6A-6D are simplified diagrams showing various views of
a modular thermoelectric unit according to one embodiment of the
present invention. These diagrams are merely examples, which should
not unduly limit the scope of the claims. One of ordinary skill in
the art would recognize many variations, alternatives, and
modifications. For example, FIG. 6A is a simplified perspective
view of the modular thermoelectric unit 500, FIG. 6B is a
simplified top view of the modular thermoelectric unit 500, FIG. 6C
is a simplified side view of the modular thermoelectric unit 500,
and FIG. 6D is another simplified side view of the modular
thermoelectric unit 500.
[0067] The modular thermoelectric unit 500 includes a hot-side heat
exchanger 510, two cold-side heat exchangers 520 and 522, and two
thermoelectric device components 531 and 532. For example, the
thermoelectric device component 531 includes one or more
thermoelectric materials. In another example, the thermoelectric
device component 532 includes one or more thermoelectric materials.
In yet another example, each of the thermoelectric device
components 531 and 532 is a thermoelectric device.
[0068] According to some embodiments, the thermoelectric device
component 531 is sandwiched between the cold-side heat exchanger
520 and the hot-side heat exchanger 510, and forms a cold junction
with the cold-side heat exchanger 520 and a hot junction with the
hot-side heat exchanger 510. According to certain embodiments, the
thermoelectric device component 532 is sandwiched between the
cold-side heat exchanger 522 and the hot-side heat exchanger 510,
and forms a cold junction with the cold-side heat exchanger 522 and
a hot junction with the hot-side heat exchanger 510. According to
some embodiments, the hot-side heat exchanger 510 forms two hot
junctions including one hot junction with the thermoelectric device
component 531 and the other hot junction with the thermoelectric
device component 532.
[0069] In one embodiment, the hot-side heat exchange 510 serves as
a heat source component, and the two cold-side heat exchangers 520
and 522 each serve as a cold sink component. In another embodiment,
the thermoelectric device component 531 includes one or more
thermoelectric device units, and the thermoelectric device
component 532 includes one or more thermoelectric device units. For
example, the thermoelectric device component 531 is configured to
convert thermal energy into electricity in response to the
temperature gradient between the corresponding cold junction and
the corresponding hot junction. In another example, the
thermoelectric device component 532 is configured to convert
thermal energy into electricity in response to the temperature
gradient between the corresponding cold junction and the
corresponding hot junction.
[0070] According to one embodiment, the hot-side heat exchanger 510
includes one or more channels for conveying one or more hot fluid
flows in a first direction 561, and each of the two cold-side heat
exchangers 520 and 522 includes one or more channels for conveying
one or more cold fluid flows in a second direction 562 according to
one embodiment. For example, the first direction 561 and the second
direction 562 are perpendicular to each other.
[0071] According to another embodiment, the thermoelectric device
component 531 includes a cold-side terminal and a hot-side
terminal. For example, the cold-side terminal is in thermal contact
with the cold-side heat exchanger 520 to form the cold junction,
and the hot-side terminal is in thermal contact with the hot-side
heat exchanger 510 to form the hot junction. According to yet
another embodiment, the thermoelectric device component 532
includes a cold-side terminal and a hot-side terminal. For example,
the cold-side terminal is in thermal contact with the cold-side
heat exchanger 522 to form the cold junction, and the hot-side
terminal is in thermal contact with the hot-side heat exchanger 510
to form the hot junction. For example, each of the thermoelectric
device components 531 and 532 is configured to convert heat (e.g.,
waste heat in the form of one or more hot fluid flows) into
electricity (e.g., useful electric energy).
[0072] In one embodiment, the hot-side heat exchanger 510 includes
a middle component 515, an inlet component 511, an outlet component
519, and transition components 513 and 517 according to one
embodiment. For example, the hot-side heat exchanger 510 has a
cuboid shape at least within a middle region 115. In another
example, the inlet component 511 and the outlet component 519 each
has a rectangular shape in side view.
[0073] In yet another example, the middle component 515 is
connected with the inlet component 511 through the transition
component 513, and is connected with the outlet component 519
through the transition component 517. In another example, each of
these two transition components 513 and 517 has a rectangular
cross-section, and the length and width of the cross-section
increases as the cross-section moves from the end of the middle
component 515 to the inlet component 511 or from the end of the
middle component 515 to the outlet component 519. In yet another
example, the two flat outer faces at the opposite sides of the
middle region 515 are used as two hot-side contact faces
respectively for the two thermoelectric device components 531 and
532. In yet another example, one or more hot flows are received by
the inlet component 511, flows through the transition component
513, the middle component 515, and the transition component 517
along the first direction 561, and are released by the outlet
component 519.
[0074] In another embodiment, the larger cross-sectional area
towards the inlet component 511 and the outlet component 519 can
facilitate the one or more fluid flows with a reduced hydraulic
resistance through the one or more channels. For example, the
entire channel of the hot-side heat exchanger 510 is made of one or
more materials (e.g., stainless steel, ceramic material) that are
rigid mechanically and tolerable for high temperature (e.g., for
high temperature up to 800.degree. C., for high temperature up to
650.degree. C.). In another example, the one or more channels are
used to convey one or more hot fluid flows, such as wasted hot
gases generated by industrial combustion processes.
[0075] As shown in FIGS. 6A-6D, the hot-side heat exchanger 510
includes three channels 580, 582 and 584, and each of the three
channels 580, 582 and 584 is used to convey a hot fluid flow in the
first direction 561 according to one embodiment. For example, the
three channels 580, 582 and 584 are disposed one by one with a
small gap between each other although they can be consolidated into
one channel. In another example, dividing one channel into three
channels with a small gap between each other can improve mechanical
tolerance of the structure with respect to thermal expansion
variation under high temperature operation. Also as shown in FIGS.
6A-6D, each of the cold-side heat exchanger 520 and 522 includes
only one channel, which is used to convey a cold fluid flow in the
second direction 562 according to another embodiment. For example,
not dividing one channel into a plurality of channels with a small
gap between each other makes the cold side more stable, leading to
a reduced loss of cold fluid flow and an improved efficiency for
the energy conversion by the thermoelectric device components 531
and 532.
[0076] In one embodiment, each of the three channels 580, 582 and
584 extends along the first direction 561, and these three channels
580, 582 and 584 are disposed next to each other along the second
direction 562. For example, corresponding to the three channels
580, 582 and 584, each of the middle component 515, the inlet
component 511, the outlet component 519, and the transition
components 513 and 517 are also divided into three parts. In
another example, the three parts of the middle component 515 has
three outer faces on each side, and these three outer faces are
leveled with each other. In yet another example, the three leveled
outer faces are configured to form thermal contacts with a
continuous contact plate as part of the thermoelectric device
component 531 or 532. In yet another example, each of the two
cold-side heat exchangers 520 and 522 includes a contact plate
overlying the three outer faces of the middle component 515 on one
side of the middle component 515.
[0077] In one embodiment, the cold-side heat exchanger 520 includes
a middle component 525, an inlet component 521, and an outlet
component 529, and the cold-side heat exchanger 522 includes a
middle component 526, an inlet component 524, and an outlet
component 528. For example, each of the cold-side heat exchangers
520 and 522 has a cuboid shape. In another example, the cold flow
is received by the inlet component 521, flows through the middle
component 525 along the second direction 562, and is released by
the outlet component 529. In yet another example, the cold flow is
received by the inlet component 524, flows through the middle
component 526 along the second direction 562, and is released by
the outlet component 528. In yet another example, for the cold-side
heat exchanger 520, a flow length 594 in the second direction 562
is kept short to reduce pumping parasitic power loss and to keep
the temperature at the outlet component 529 low. In yet another
example, for the cold-side heat exchanger 522, a flow length in the
second direction 562 is kept short to reduce pumping parasitic
power loss and to keep the temperature at the outlet component 528
low.
[0078] In another embodiment, each of the cold-side heat exchangers
520 and 522 is subjected to a relative low temperature (e.g., about
10.degree. C. or lower, about 80.degree. C. or lower), and is made
of one or more materials with high thermal conductivity material
and low manufacturing cost. In yet another embodiment, the
cold-side heat exchanger 520 includes a contact plate 590, and the
cold-side heat exchanger 522 includes a contact plate 592. For
example, both the contact plates 590 and 592 are positioned to face
outside, thus reducing heat loss to the atmosphere from the
hot-side heat exchanger 510 not directed through the thermoelectric
device components 531 and 532 and also protecting other system
components from high temperatures.
[0079] According to one embodiment, the hot-side heat exchanger 510
includes at least the middle component 515, the inlet component
511, the transition components 513 and 517, and the outlet
component 519 according to one embodiment. For example, the middle
component 515 has a top-side plate 614 and a bottom-side plate 616,
and is connected with the inlet component 511 through the
transition component 513. In another example, the transition
component 513 uses a sloped edge at both the top side and the
bottom side and connects the inlet component 511 to one end of the
top-side plate 614 and the bottom-side plate 616 of the middle
component 515 respectively. In yet another example, the inlet
component 511 has a cross-sectional dimension 680 that is larger
than the distance along a third direction 563 between the top-side
plate 614 and the bottom-side plate 616 of the middle component
511, in order to provide space for disposing the cold-side heat
exchangers 520 and 522 on the top side and the bottom side
respectively.
[0080] According to another embodiment, the transition component
517 is substantially similar to the transition component 513 and is
used to connect the middle component 515 to the outlet component
519 through the transition component 517. For example, the
transition component 513 uses a sloped edge at both the top side
and the bottom side and connects the outlet component 519 to
another end of the top-side plate 614 and the bottom-side plate 616
of the middle component 515 respectively. In another example, the
outlet component 519 has a cross-sectional dimension 688 that is
larger than the distance along the third direction 563 between the
top-side plate 614 and the bottom-side plate 616 of the middle
component 511, in order to provide space for disposing the
cold-side heat exchangers 520 and 522 on the top side and the
bottom side respectively.
[0081] As shown in FIG. 6D, the cold-side heat exchanger 520
includes a channel 624 between contact plates 623 and 590, and the
cold-side heat exchanger 522 includes a channel 628 between contact
plates 627 and 592. In one embodiment, the channel 624 includes a
plurality of fingers 620 that extend from the contact plate 623 to
the contact plate 590. For example, the length 630 of each finger
620 is equal to or less than 8 cm. In another example, the length
630 of each finger 620 is equal to or less than 6 cm. In yet
another example, the length 630 of each finger 620 is equal to or
less than 4 cm. In another embodiment, the channel 628 includes a
plurality of fingers 622 that extend from the contact plate 627 to
the contact plate 592. For example, the length 632 of each finger
622 is equal to or less than 8 cm. In another example, the length
632 of each finger 622 is equal to or less than 6 cm. In yet
another example, the length 632 of each finger 622 is equal to or
less than 4 cm.
[0082] In one embodiment, for the channel 624, each part of the
cold fluid flow (that moves through the channel 624) corresponds to
a shortest distance to the thermoelectric device component 531, and
the shortest distance is less than half the square root of the
total free flow area for a corresponding cross-section of the fluid
flow. For example, the corresponding cross-section of the fluid
flow is perpendicular to the second direction 562, and the total
free flow area for the corresponding cross-section is equal to the
cross-sectional area of the channel 624 minus the corresponding
cross-section areas of the fingers.
[0083] In another embodiment, for the channel 628, each part of the
cold fluid flow (that moves through the channel 628) corresponds to
a shortest distance to the thermoelectric device component 532, and
the shortest distance is less than half the square root of the
total free flow area for a corresponding cross-section of the fluid
flow. For example, the corresponding cross-section of the fluid
flow is perpendicular to the second direction 562, and the total
free flow area for the corresponding cross-section is equal to the
cross-sectional area of the channel 628 minus the corresponding
cross-section areas of the fingers.
[0084] According to certain embodiments, the channel 624 includes a
plurality of fin structures (e.g., fingers) that are aligned in the
second direction 562 (e.g., into the paper as shown in FIG. 6D) for
conveying the cold fluid flow, and the channel 628 also includes a
plurality of fin structures (e.g., fingers) that are aligned in the
second direction 562 (e.g., into the paper as shown in FIG. 6D) for
conveying the cold fluid flow. For example, the plurality of fin
structures enhance thermal conductivity for transferring heat from
the thermoelectric device component 531 through the contact plate
623 to the cold fluid flow in the cold channel 624. By maintaining
a certain rate of the cold fluid flow, a substantially stable
cold-side temperature can be maintained at the cold junction of the
thermoelectric device component 531. In another example, the
plurality of fin structures enhance thermal conductivity for
transferring heat from the thermoelectric device component 532
through the contact plate 627 to the cold fluid flow in the cold
channel 628. By maintaining a certain rate of the cold fluid flow,
a substantially stable cold-side temperature can be maintained at
the cold junction of the thermoelectric device component 532.
[0085] According to some embodiments, the height of each cold
channel (e.g., the channel 624 or 628) as disposed in the modular
thermoelectric unit 500 is configured to fit the space provided by
the reduced dimension of the middle component 515 in comparison
with the inlet component 511 and the outlet region component 519 of
the hot-side heat exchanger 510. For example, the distance between
two outside contact plates 590 and 592 is substantially equal to
the cross-sectional dimension 680 of the inlet component 511 and
the cross-sectional dimension 688 of the outlet component 519,
providing convenience for packing a plurality of modular
thermoelectric units 500 along the third direction 563, which is
perpendicular to both the first direction 561 and the second
direction 562.
[0086] As shown in FIG. 6C, the hot-side heat exchanger 510
includes three channels 580, 582 and 584, and each of the three
channels 580, 582 and 584 is used to convey a hot fluid flow in the
first direction 561 according to one embodiment. For example, the
channel 580 is located between contact plates 660 and 662, the
channel 582 is located between contact plates 664 and 666, and the
channel 584 is located between contact plates 668 and 670. In
another example, the channel 580 includes a plurality of fingers
661 that extend from the contact plate 660 to the contact plate
662, the channel 582 includes a plurality of fingers 665 that
extend from the contact plate 664 to the contact plate 666, and the
channel 584 includes a plurality of fingers 669 that extend from
the contact plate 668 to the contact plate 670. In yet another
example, the length 671 of each finger (e.g., the finger 661, 665,
or 670) is equal to or less than 8 cm. In yet another example, the
length 671 of each finger (e.g., the finger 661, 665, or 670) is
equal to or less than 6 cm. In yet another example, the length 671
of each finger (e.g., the finger 661, 665, or 670) is equal to or
less than 4 cm.
[0087] In one embodiment, for the channel 580, each part of the hot
fluid flow (that moves through the channel 580) corresponds to a
shortest distance to the thermoelectric device component 531 and
another shortest distance to the thermoelectric device component
532, and both these two shortest distances are less than half the
square root of the total free flow area for a corresponding
cross-section of the fluid flow. For example, the corresponding
cross-section of the fluid flow is perpendicular to the first
direction 561, and the total free flow area for the corresponding
cross-section is equal to the cross-sectional area of the channel
580 minus the corresponding cross-section areas of the fingers.
[0088] In another embodiment, for the channel 582, each part of the
hot fluid flow (that moves through the channel 582) corresponds to
a shortest distance to the thermoelectric device component 531 and
another shortest distance to the thermoelectric device component
532, and both these two shortest distances are less than half the
square root of the total free flow area for a corresponding
cross-section of the fluid flow. For example, the corresponding
cross-section of the fluid flow is perpendicular to the first
direction 561, and the total free flow area for the corresponding
cross-section is equal to the cross-sectional area of the channel
582 minus the corresponding cross-section areas of the fingers.
[0089] In yet another embodiment, for the channel 584, each part of
the hot fluid flow (that moves through the channel 584) corresponds
to a shortest distance to the thermoelectric device component 531
and another shortest distance to the thermoelectric device
component 532, and both these two shortest distances are less than
half the square root of the total free flow area for a
corresponding cross-section of the fluid flow. For example, the
corresponding cross-section of the fluid flow is perpendicular to
the first direction 561, and the total free flow area for the
corresponding cross-section is equal to the cross-sectional area of
the channel 584 minus the corresponding cross-section areas of the
fingers.
[0090] According to another embodiment, the channels 580, 582 and
584 each include a plurality of fin structures (e.g., fingers) that
are aligned in the first direction 561 (e.g., into the paper as
shown in FIG. 6C) at least in the middle component 515 for
conveying the hot fluid flows. For example, such fin structures
enhance thermal conductivity between the hot fluid flows and the
thermoelectric device components 531 and 532.
[0091] As discussed above and further emphasized here, FIGS. 6A-6D
are merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. In one embodiment, the
modular thermoelectric unit 500 is a modular heat recovery unit. In
another embodiment, one or more modular thermoelectric units 500
are provided for assembling a heat recovery system to be installed
in a waste heat exhaust region associated with industrial
combustion processes.
[0092] According to one embodiment, the coupling configuration
between the hot-side heat exchanger 510 and the two cold-side heat
exchangers 520 and 522 keeps at least the middle component 515 of
the hot-side heat exchanger 510 between the two cold-side heat
exchangers 520 and 522. For example, such configuration can help
maintain at least the middle component 515 with one or more hot
fluid flows in a substantially stable, high temperature state.
[0093] According to another embodiment, the hot-side heat exchanger
510 includes the transition components 513 and 517, each with
increasing cross-sectional area to connect the middle component 515
with the inlet component 511 or the outlet component 519. For
example, such configuration provides the inlet component 511 and
the outlet component 519 with large cross-sectional areas that can
facilitate the smooth flow and also enhance the flow rate in the
middle component 515 for better efficiency in thermal conduction.
In another example, such configuration can match the dimension of
the hot-side heat exchanger 51 in the third direction 563 with the
distance between the two contact plates 590 and 592 as shown in
FIG. 6D.
[0094] As shown in FIGS. 6A-6D, the thermoelectric device component
531 is sandwiched between the cold-side heat exchanger 520 and the
hot-side heat exchanger 510, and forms a cold junction with the
cold-side heat exchanger 520 and a hot junction with the hot-side
heat exchanger 510, and the thermoelectric device component 532 is
sandwiched between the cold-side heat exchanger 522 and the
hot-side heat exchanger 510, and forms a cold junction with the
cold-side heat exchanger 522 and a hot junction with the hot-side
heat exchanger 510 according to some embodiments. For example, the
shortest path from any unit of a hot fluid flow or a cold fluid
flow to its corresponding thermoelectric junction (e.g., a
corresponding hot junction or a corresponding cold junction) is
less than 3 inches. According to some embodiments, the modular
thermoelectric unit 500 includes the hot-side heat exchanger 510,
the cold-side heat exchangers 520 and 522, and the thermoelectric
device components 531 and 532. For example, the hot-side heat
exchanger 510 is used to extract heat from one or more
corresponding hot fluid flows. In another example, each of the
cold-side heat exchangers 520 and 522 is used to discharge heat to
one or more corresponding cold fluid flows.
[0095] According to some embodiments, one or more of the following
considerations (a) through (d) are taken into account:
[0096] (a) To increase net electric power generation and reduce
system size for a thermoelectric generator (e.g., a thermoelectric
system), it is desirable to use one or more hot-side heat
exchangers and one or more cold-side heat exchangers that create
low thermal resistance (e.g., high heat transfer) from one or more
corresponding hot or cold fluid flows to one or more corresponding
thermoelectric device components, while providing a low pressure
drop to the one or more corresponding hot or cold fluid flows that
pass through the corresponding heat exchangers, respectively,
according to certain embodiments. For example, a lower thermal
resistance allows one or more corresponding hot-side heat
exchangers to extract more heat for a given area and thus allows a
thermoelectric generator to generate more power per unit volume. In
another example, a pressure drop needs to be compensated for by one
or more pumps and/or fans, which consume parasitic energy and thus
reduce net power generation.
[0097] (b) The heat transfer is proportional to the surface area in
contact with the corresponding flow fluid and is proportional to
the fluid velocity, and the pressure drop is proportional to the
surface area in contact with the corresponding flow fluid and is
proportional to the cube of the fluid velocity; therefore a high
heat transfer, low pressure drop heat exchanger can be achieved
with a low fluid velocity and a high surface area according to
certain embodiments. For example, a low fluid velocity can be
obtained by increasing the free-flow cross-sectional area of the
heat exchanger. In another example, a high surface area can be
achieved using fins (e.g., fingers), pins, web, channels or other
extended surface area features on the heat exchange surfaces.
[0098] (c) Heat needs to conduct down the length of any fin or
extended surface to the thermoelectric device component, and such
length of heat conduction introduces thermal resistance, and the
thermal resistance of a fin is proportional to the length of the
conductive path, and inversely proportional to the width of the
conductive path and the thermal conductivity of heat exchanger
material according to certain embodiments. For example, high
thermal conductivity materials are expensive (e.g., copper, gold,
silver, silicon carbide, aluminum nitride) or are not suitable for
high temperature applications due to softening or oxidation (e.g.,
aluminum, graphite). In another example, a wider fin reduces the
free-flow area thereby increasing the pressure drop and reducing
the net power generation. In yet another example, a short
conductive length can be achieved by using one or more wide but
shallow heat exchanger channels; however such channel geometry can
create a thermoelectric system with physical dimensions that may be
difficult to work with. In yet another example, such difficulty can
be overcome by dividing or manifolding the fluid flow and layering
multiple stacks of one or more hot-side heat exchangers, one or
more thermoelectric device components, and one or more cold-side
heat exchangers in parallel to the fluid flow.
[0099] (d) A larger number of stacked hot and/or cold channels
without fins, but with even lower channel height can provide an
equivalent free flow cross sectional area and an equivalent surface
area and thus may also achieve a low fluid velocity, a high surface
area and a short conductive path according to certain embodiments.
As an example, such arrangement is less effective for a
thermoelectric generator that requires thermal impedance matching
of the thermoelectric device components with the heat exchangers in
order to maximize power generation. In another example, a heat
exchanger arrangement without extended surface area have a low heat
transfer per unit area of thermoelectric material, so one or more
thicker thermoelectric device components and/or a lower packing
fraction of thermoelectric material are needed. In yet another
example, a thicker thermoelectric device component may result in
higher thermoelectric material costs. In yet another example, a
lower packing fraction of thermoelectric material may result in
loss of power due to leakage of heat through the spaces around the
thermoelectric device components.
[0100] As discussed above and further emphasized here, FIGS. 6A-6D
are merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. For example, the two
thermoelectric device components 531 and 532 are replaced by two
devices that are not thermoelectric devices but can still convert
thermal energy to electric energy. In another example, the two
thermoelectric device components 531 and 532 are replaced by
certain types of thermophotovoltaic devices, each of which includes
one or more certain types of thermophotovoltaic materials. In yet
another example, the two thermoelectric device components 531 and
532 are replaced by certain types of thermionic devices, each of
which includes one or more certain types of thermionic
materials.
[0101] In another example, the first direction 561 is not fixed,
but instead the first direction 561 changes as the one or more hot
fluid flows move through the one or more channels of the hot-side
heat exchanger 510. In yet another example, the second direction
562 is not fixed, but instead the second direction 562 changes as
the one or more cold fluid flows move through the one or more
channels of the cold-side heat exchanger 520 and/or the one or more
channels of the cold-side heat exchanger 522.
[0102] FIG. 7 is a simplified diagram showing certain components of
the modular thermoelectric unit 500 as shown in FIGS. 6A-6D
according to one embodiment of the present invention. This diagram
is merely an example, which should not unduly limit the scope of
the claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications.
[0103] As described above, the thermoelectric device component 531
is sandwiched between the cold-side heat exchanger 520 and the
hot-side heat exchanger 510, and forms the cold junction with the
cold-side heat exchanger 520 and the hot junction with the hot-side
heat exchanger 510, and the thermoelectric device component 532 is
sandwiched between the cold-side heat exchanger 522 and the
hot-side heat exchanger 510, and forms the cold junction with the
cold-side heat exchanger 522 and the hot junction with the hot-side
heat exchanger 510, according to certain embodiments. For example,
on one side of the middle component 515, the contact plate 623 of
the cold-side heat exchanger 520 is engaged to form the cold
junction with the thermoelectric device component 531, while
leaving the contact plate 590 facing outside of the modular
thermoelectric unit 500. In another example, on another side of the
middle component 515, the contact plate 627 of the cold-side heat
exchanger 522 is engaged to form a cold junction with the
thermoelectric device component 532, while leaving the contact
plate 592 facing outside of the modular thermoelectric unit
500.
[0104] In one embodiment, the thermoelectric device component 531
includes a plurality of thermoelectric device units 640 embedded in
a low thermal-conductivity matrix 642 and sandwiched between two
terminals 641 and 643. For example, the terminal 641 serves as a
contact plate for forming the hot junction with the contact plate
614 of the hot-side heat exchanger 510, and the terminal 643 serves
as a contact plate for forming the cold junction with the contact
plate 623 of the cold-side heat exchanger 520. In another example,
the terminals 641 and 643 also serve as electrical shunts for
outputting electrical power generated by the thermoelectric device
component 531 in response to a temperature gradient between the hot
junction and the cold junction.
[0105] In another embodiment, the thermoelectric device component
532 includes a plurality of thermoelectric device units 650
embedded in a low thermal-conductivity matrix 652 and sandwiched
between two terminals 651 and 653. For example, the terminal 651
serves as a contact plate for forming the hot junction with the
contact plate 616 of the hot-side heat exchanger 510, and the
terminal 653 serves as a contact plate for forming the cold
junction with the contact plate 627 of the cold-side heat exchanger
522. In another example, the terminals 651 and 653 also serve as
electrical shunts for outputting electrical power generated by the
thermoelectric device component 532 in response to a temperature
gradient between the hot junction and the cold junction.
[0106] As shown in FIG. 7, an interfacial material 675 is inserted
between the terminal 641 and the contact plate 614, and another
interfacial material 676 is inserted between the terminal 643 and
the contact plate 623 according to certain embodiments. For
example, the interfacial material 675 is used to ensure excellent
thermal conductivity between the terminal 641 and the contact plate
614. In another example, the interfacial material 676 is used to
ensure excellent thermal conductivity between the terminal 643 and
the contact plate 623. In one embodiment, the interfacial material
675 is suitable with the high temperature environment (e.g., up to
800.degree. C. or higher, up to 650.degree. C. or higher) near the
hot-side heat exchanger 510. For example, the interfacial material
675 uses a metal foil, in particular a copper foil, because the
metal foil tends to be softened at high temperature, thus becoming
an excellent thermal contact medium as the contact plate 614 is
pressed against the terminal 641. In another embodiment, the
interfacial material 676 is thin in order to enhance through-plane
thermal conductivity. For example, the interfacial material 676
uses a graphite foil, because low levels of pressure can cause the
graphite foil to flatten out as the contact plate 623 is pressed
against the terminal 643. According to some embodiments, an
interfacial material (e.g., similar to the interfacial material
675) is inserted between the terminal 651 and the contact plate
616, and another interfacial material (e.g., similar to the
interfacial material 676) is inserted between the terminal 653 and
the contact plate 627.
[0107] FIG. 8A is a simplified diagram showing some components of
the modular thermoelectric unit 500 as shown in FIGS. 6A-6D
according to another embodiment of the present invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications.
[0108] As shown in FIG. 8A, the hot-side heat exchanger 510
includes the three channels 580, 582 and 584, located between the
channel 624 of the cold-side heat exchanger 520 and the channel 628
of the cold-side heat exchanger 522. For example, between the cold
channel 624 and the three hot channels 580, 582 and 584, there is
the thermoelectric device component 531 (e.g., with high
thermoelectric figure of merit). In another example, between the
cold channel 628 and the three hot channels 580, 582 and 584, there
is the thermoelectric device component 532 (e.g., with high
thermoelectric figure of merit).
[0109] In one embodiment, the thermoelectric device component 531
includes a plurality of thermoelectric device units 730 (e.g., the
plurality of thermoelectric device units 640), and the
thermoelectric device component 532 includes a plurality of
thermoelectric device units 732 (e.g., a plurality of
thermoelectric device units 650). For example, the plurality of
thermoelectric device units 730 are aligned along the first
direction 562, and the plurality of thermoelectric device units 732
are also aligned along the first direction 562. In another example,
each thermoelectric device unit of the plurality of thermoelectric
device units 730 and/or the plurality of thermoelectric device
units 732 is made from an array of nanowires through semiconductor
fabrication processes.
[0110] In yet another example, each thermoelectric device unit of
the plurality of thermoelectric device units 730 is functionalized
into either a p-type semiconductor unit (e.g., a p-type
thermoelectric leg) with low thermal conductivity and high
electrical conductivity, or an n-type semiconductor unit (e.g., an
n-type thermoelectric leg) with low thermal conductivity and high
electrical conductivity. In yet another example, each
thermoelectric device unit of the plurality of thermoelectric
device units 732 is functionalized into either a p-type
semiconductor unit with low thermal conductivity and high
electrical conductivity, or an n-type semiconductor unit with low
thermal conductivity and high electrical conductivity. In yet
another example, the p-type semiconductor and the n-type
semiconductor each are a thermoelectric material.
[0111] According to one embodiment, the plurality of thermoelectric
device units 730 include p-type semiconductor units and n-type
semiconductor units. For example, two p-type semiconductor units
are separated by at least one n-type semiconductor unit, and two
n-type semiconductor units are separated by at least one p-type
semiconductor unit. In another example, the plurality of
thermoelectric device units 730 are electrically coupled to each
other (e.g., each n-type semiconductor unit being electrically
connected to one or two p-type semiconductor units, each p-type
semiconductor unit being electrically connected to one or two
n-type semiconductor units). According to another embodiment, the
plurality of thermoelectric device units 732 include p-type
semiconductor units and n-type semiconductor units. For example,
two p-type semiconductor units are separated by at least one n-type
semiconductor unit, and two n-type semiconductor units are
separated by at least one p-type semiconductor unit. In another
example, the plurality of thermoelectric device units 732 are
electrically coupled to each other (e.g., each n-type semiconductor
unit being electrically connected to one or two p-type
semiconductor units, each p-type semiconductor unit being
electrically connected to one or two n-type semiconductor
units).
[0112] As shown in FIG. 8A, the plurality of thermoelectric device
units 730 are divided into three groups 740, 742, and 744 of
thermoelectric device units corresponding to the three channels
580, 582 and 584 respectively, and the plurality of thermoelectric
device units 732 are divided into three groups 750, 752, and 754 of
thermoelectric device units corresponding to the three channels
580, 582 and 584 respectively. For example, the three channels 580,
582 and 584 are disposed one by one with a small gap between each
other in order to improve mechanical tolerance of the structure
with respect to thermal expansion variation under high temperature
operation. In another example, across each such small gap, a
flexible connector 746 (e.g., a cable) is used to electrically link
the groups 740 and 742 or the groups 742 and 744, and a flexible
connector 756 (e.g., a cable) is used to electrically link the
groups 750 and 752 or the groups 752 and 754.
[0113] In one embodiment, an end unit of the group 740 is
electrically connected to an insulated cable 760 through a flexible
connector 746, and an end unit of the group 750 is also
electrically connected to the insulated cable 760 through a
flexible connector 756. For example, the insulated cable 760 can
tolerate a high temperature (e.g., up to 800.degree. C. or higher,
up to 650.degree. C. or higher). In another example, the insulated
cable 760 is partially attached to the cold-side heat exchangers
520 and 522. In another embodiment, an end unit of the group 744 is
electrically connected to an insulated cable 762 through a flexible
connector 746, and an end unit of the group 754 is also
electrically connected to the insulated cable 764 through a
flexible connector 756. For example, the insulated cable 762 is
partially attached to the cold-side heat exchanger 520, and the
insulated cable 764 is partially attached to the cold-side heat
exchanger 522. In another example, the insulated cables 762 and 764
are used as main electrodes for connecting to corresponding
external electrical leads. In yet another example, the insulated
cables 762 and 764 are used to couple electrically with a
neighboring modular thermoelectric unit 500 if multiple modular
thermoelectric units 500 are assembled together to form a subsystem
or a system. In yet another example, the insulated cables 762 and
764 are used to transfer the electric energy (e.g., electricity)
that is converted from the thermal energy by the thermoelectric
device components 531 and 532 through thermoelectric
conversion.
[0114] FIG. 8B is a simplified diagram showing some components of
the modular thermoelectric unit 500 as shown in FIGS. 6A-6D
according to yet another embodiment of the present invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications.
[0115] As shown in FIG. 8B, the hot-side heat exchanger 510
includes the three channels 580, 582 and 584, located between the
channel 624 of the cold-side heat exchanger 520 and the channel 628
of the cold-side heat exchanger 522. For example, between the cold
channel 624 and the three hot channels 580, 582 and 584, there is
the thermoelectric device component 531 (e.g., with high
thermoelectric figure of merit). In another example, between the
cold channel 628 and the three hot channels 580, 582 and 584, there
is the thermoelectric device component 532 (e.g., with high
thermoelectric figure of merit).
[0116] In one embodiment, the thermoelectric device component 531
includes a plurality of thermoelectric device units 730 (e.g., the
plurality of thermoelectric device units 640), and the
thermoelectric device component 532 includes a plurality of
thermoelectric device units 732 (e.g., a plurality of
thermoelectric device units 650). For example, the plurality of
thermoelectric device units 730 are aligned along the first
direction 562, and the plurality of thermoelectric device units 732
are also aligned along the first direction 562. In another example,
each thermoelectric device unit of the plurality of thermoelectric
device units 730 and/or the plurality of thermoelectric device
units 732 is made from an array of nanowires through semiconductor
fabrication processes.
[0117] In yet another example, each thermoelectric device unit of
the plurality of thermoelectric device units 730 is functionalized
into either a p-type semiconductor unit with low thermal
conductivity and high electrical conductivity, or an n-type
semiconductor unit with low thermal conductivity and high
electrical conductivity. In yet another example, each
thermoelectric device unit of the plurality of thermoelectric
device units 732 is functionalized into either a p-type
semiconductor unit with low thermal conductivity and high
electrical conductivity, or an n-type semiconductor unit with low
thermal conductivity and high electrical conductivity.
[0118] According to one embodiment, the plurality of thermoelectric
device units 730 include p-type semiconductor units and n-type
semiconductor units. For example, two p-type semiconductor units
are separated by at least one n-type semiconductor unit, and two
n-type semiconductor units are separated by at least one p-type
semiconductor unit. In another example, the plurality of
thermoelectric device units 730 are electrically coupled to each
other (e.g., each n-type semiconductor unit being electrically
connected to one or two p-type semiconductor units, each p-type
semiconductor unit being electrically connected to one or two
n-type semiconductor units). According to another embodiment, the
plurality of thermoelectric device units 732 include p-type
semiconductor units and n-type semiconductor units. For example,
two p-type semiconductor units are separated by at least one n-type
semiconductor unit, and two n-type semiconductor units are
separated by at least one p-type semiconductor unit. In another
example, the plurality of thermoelectric device units 732 are
electrically coupled to each other (e.g., each n-type semiconductor
unit being electrically connected to one or two p-type
semiconductor units, each p-type semiconductor unit being
electrically connected to one or two n-type semiconductor
units).
[0119] As shown in FIG. 8B, the plurality of thermoelectric device
units 730 are divided into three groups 740, 742, and 744 of
thermoelectric device units corresponding to the three channels
580, 582 and 584 respectively, and the plurality of thermoelectric
device units 732 are divided into three groups 750, 752, and 754 of
thermoelectric device units corresponding to the three channels
580, 582 and 584 respectively. For example, the three channels 580,
582 and 584 are disposed one by one with a small gap between each
other in order to improve mechanical tolerance of the structure
with respect to thermal expansion variation under high temperature
operation.
[0120] In another example, each of the two groups 740 and 742 are
electrically connected to an insulated cable 776 that extends
beyond the contact plate 590 of the cold-side heat exchanger 520,
and these insulated cables 776 are connected to each other by an
insulated cable 792. In yet another example, each of the two groups
742 and 744 are electrically connected to an insulated cable 776
that extends beyond the contact plate 590 of the cold-side heat
exchanger 520, and these insulated cables 776 are connected to each
other by an insulated cable 792.
[0121] In yet another example, each of the two groups 750 and 752
are electrically connected to an insulated cable 786 that extends
beyond the contact plate 592 of the cold-side heat exchanger 522,
and these insulated cables 786 are connected to each other by an
insulated cable 794. In yet another example, each of the two groups
752 and 754 are electrically connected to an insulated cable 786
that extends beyond the contact plate 592 of the cold-side heat
exchanger 522, and these insulated cables 786 are connected to each
other by an insulated cable 794.
[0122] In yet another example, the group 740 is electrically
connected to an insulated cable 776 that extends beyond the contact
plate 590 of the cold-side heat exchanger 520, and the group 750 is
electrically connected to an insulated cable 786 that extends
beyond the contact plate 592 of the cold-side heat exchanger 522,
wherein these insulated cables 776 and 786 are connected to each
other by an insulated cable 790. In yet another example, the group
744 is electrically connected to an insulated cable 776 that
extends beyond the contact plate 590 of the cold-side heat
exchanger 520, and the group 754 is electrically connected to an
insulated cable 786 that extends beyond the contact plate 592 of
the cold-side heat exchanger 522, wherein the insulated cable 776
is connected to an insulated cable 796 and the insulated cable 786
is connected to an insulated cable 798. In one embodiment, the
insulated cables 796 and 798 are used as main electrodes for
connecting to corresponding external electrical leads. In another
embodiment, the insulated cables 796 and 798 are used to couple
electrically with a neighboring modular thermoelectric unit 500 if
multiple modular thermoelectric units 500 are assembled together to
form a subsystem or a system.
[0123] FIG. 9 is a simplified diagram showing certain components of
the modular thermoelectric unit 500 as shown in FIGS. 6A-6D
according to yet another embodiment of the present invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications.
[0124] As described above, the thermoelectric device component 531
is sandwiched between the cold-side heat exchanger 520 and the
hot-side heat exchanger 510, and the thermoelectric device
component 532 is sandwiched between the cold-side heat exchanger
522 and the hot-side heat exchanger 510 according to some
embodiments.
[0125] In an embodiment, the cold-side heat exchanger 520 is
mounted by at least one bolt assembly 840 in an extended end region
of the contact plate 623 so that the contact plate 623 is pressed
against the thermoelectric device component 531, which in turn is
pressed against the hot-side heat exchanger 510, and the hot-side
heat exchanger 510 is further pressed against the thermoelectric
device component 531 and the contact plate 627 of the cold-side
heat exchanger 522. For example, the bolt assembly 840 includes a
top portion above the contact plate 623, a bottom portion below the
contact plate 627, and a middle portion between the contact plates
623 and 627. In another example, the top portion of the bolt
assembly 840 includes a bolt head 820 and a spring washer 822. In
yet another example, the bottom portion of the bolt assembly 840
includes a nut 824 that is coupled to the bolt that extends from
the contact plate 623 of the cold-side heat exchanger 520 to the
contact plate 627 of the cold-side heat exchanger 522 to the
contact plate 623. In yet another example, the middle portion of
the bolt assembly 840 includes a spacer 810 that is both thermally
and electrically insulating so that the bolt does not make any
thermal and electrical contact with the hot-side heat exchanger 510
and does not make any thermal and electrical contact with any of
the thermoelectric device component 531 or 532.
[0126] According to one embodiment, the bolt assembly 840 is
tightened when all of the hot-side heat exchanger 510 and the
cold-side heat exchangers 520 and 522 are cold. For example,
afterwards, when the hot-side heat exchanger 510 becomes hot during
normal operation, the middle portion of the bolt assembly 840 would
expand in length, and such thermal expansion is accommodated by the
spring washer 822, which remains cold in part due to the insulating
spacer 810. According to another embodiment, as shown in FIG. 6B,
the modular thermoelectric unit 500 includes multiple bolt
assemblies 502. For example, each of the multiple bolt assemblies
502 is the same as the bolt assembly 840.
[0127] As shown in FIG. 9 and/or FIGS. 6A-6D, the modular
thermoelectric unit 500 includes the thermoelectric device
components 531 sandwiched between the hot-side heat exchanger 510
and the cold-side heat exchanger 520, and the thermoelectric device
components 532 sandwiched between the hot-side heat exchanger 510
and the cold-side heat exchanger 522 according to certain
embodiments. In one embodiment, the thermoelectric device
components 531 and the cold-side heat exchangers 520 are on one
side of the hot-side heat exchanger 510, and the thermoelectric
device components 532 and the cold-side heat exchangers 522 are on
another side of the hot-side heat exchanger 510. In another
embodiment, the bolt assembly 840 (e.g., a bolt) extends from the
cold-side heat exchangers 520 to the cold-side heat exchangers 522,
without making contact with the hot-side heat exchanger 510 and
without making contact with any of the thermoelectric device
components 531 and 532.
[0128] According to some embodiments, one or more of the following
considerations (A) and (B) are taken into account:
[0129] (A) The bolt assembly 840 applies compressive force to the
hot-side heat exchanger 510 and the thermoelectric device
components 531 and 532 according to certain embodiments. For
example, the bolt assembly 840 reduces thermal resistance of the
contacts by applying a pressure to one or more compliant materials
at the interfaces between the thermoelectric device components 531
and 532 and the heat exchangers 510, 520, and 522, without
producing a thermal short between the hot-side heat exchanger 510
and the cold-side heat exchanger 520 and without producing a
thermal short between the hot-side heat exchanger 510 and the
cold-side heat exchangers 522. In another example, any of such
thermal short would reduce both the temperature gradient and the
heat flux across the thermoelectric device components 531 and
across the thermoelectric device components 532, thus also reducing
the amount power produced by the modular thermoelectric unit
500.
[0130] (B) Extending the bolt assembly 840 from the cold-side heat
exchangers 520 to the cold-side heat exchangers 522 can reduce the
design temperature requirement of the bolt assembly 840 including
the spring washer 822 according to certain embodiments. For
example, extending the bolt assembly 840 from the cold-side heat
exchanger 520 to the cold-side heat exchanger 522 can reduce the
heat loss of the hot-side heat exchanger 510 to the atmosphere by
placing the hot-side heat exchanger 510 between the cold-side heat
exchangers 520 and 522.
[0131] According to some embodiments, also referring to FIGS.
3A-3B, one or more bolt assemblies that are similar to the bolt
assembly 840 are used to extend, for example, from the heat source
component 212 (e.g., a hot-side heat exchanger) to the heat source
component 214 (e.g., a hot-side heat exchanger).
[0132] As discussed above and further emphasized here, FIG. 9 is
merely an example, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. For example, the bolt
assembly 840 that includes a bolt is replaced by another component
that can also apply a compressive force to the cold-side heat
exchanger 520, the thermoelectric device component 531, the
hot-side heat exchanger 510, the thermoelectric device component
532, and the cold-side heat exchanger 522.
[0133] FIG. 10 is a simplified diagram showing a modular
thermoelectric subsystem according to one embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications.
[0134] The modular thermoelectric subsystem 900 includes multiple
modular thermoelectric units 901 stacking together (e.g., four
modular thermoelectric units 901 stacking together) according to
one embodiment. For example, each modular thermoelectric unit 901
is a modular thermoelectric units 500 as shown in FIGS. 6A-6D. In
another example, the stacking of multiple modular thermoelectric
units 901 is performed along the third direction 563 as shown in
FIG. 6D.
[0135] In one embodiment, the dimension of the inlet component 511
and the outlet component 519 of the hot-side heat exchanger 510
along the third direction 563 matches (e.g., being equal to or
being smaller than) the distance between the contact plates 590 and
592 along the third direction, so the stacking of multiple modular
thermoelectric units 901 (e.g., the stacking of multiple modular
thermoelectric units 500) along the third direction 563 allows
formation a combined inlet component 911 and a combined outlet
component 919 for all the hot channels of the assembled multiple
modular units.
[0136] In another embodiment, the stacking of multiple modular
thermoelectric units 901 (e.g., the stacking of multiple modular
thermoelectric units 500) along the third direction 563 allows the
contact plate 590 of one modular thermoelectric unit to be in good
thermal contact with the contact plate 592 of a neighboring modular
thermoelectric unit, forming a combined inlet component 921 and a
combined outlet component 929 for all the cold channels of the
assembled multiple modular units.
[0137] As shown in FIG. 10, the modular thermoelectric subsystem
900 includes a duct structure 940 associated with the combined
inlet component 921 for all the cold channels. For example, the
duct structure 940 includes multiple shaped sides 941 to extend the
combined inlet component 921 to an enlarged opening. In another
example, the duct structure 940 also includes multiple shaped
insulation blockers 942 to prevent the cold fluid flows to directly
contact the exposed side surfaces of the hot channels.
[0138] In one embodiment, a fan or pump structure is installed at
the opening of the duct structure 940 for driving the cold fluid
flows through all of the cold channels along the second direction
362. In another embodiment, an exhaust fan or pump structure is
installed at the opening of the combined outlet component 919 for
maintaining a desired flow rate for all of the hot fluid flows
along the first direction 361. In yet another embodiment, multiple
modular thermoelectric subsystems 400 are stacked up to form a
thermoelectric system. For example, such stacking of multiple
modular thermoelectric subsystems 400 is performed along the third
direction 563. In another example, such stacking of multiple
modular thermoelectric subsystems 400 is performed along the first
direction 561 and/or the second direction 562.
[0139] FIGS. 11A-11B are simplified diagrams showing a modular
thermoelectric subsystem according to another embodiment of the
present invention. These diagrams are merely examples, which should
not unduly limit the scope of the claims. One of ordinary skill in
the art would recognize many variations, alternatives, and
modifications.
[0140] In one embodiment, the modular thermoelectric subsystem 1000
includes external components 1110 and internal components 1120
inside the external components 1110. In another embodiment, the
modular thermoelectric subsystem 1000 is the same as or
substantially similar with the modular thermoelectric subsystem
900.
[0141] As discussed above and further emphasized here, FIG. 10 and
FIGS. 11A-11B are merely examples, which should not unduly limit
the scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications. For
example, the modular thermoelectric subsystem 900 includes only one
modular thermoelectric units 901.
[0142] FIG. 12 is a simplified diagram showing a thermoelectric
system according to one embodiment of the present invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications.
[0143] As shown in FIG. 12, the thermoelectric system 1100 includes
multiple modular thermoelectric subsystems 1110 (e.g., five modular
thermoelectric subsystems 1110). For example, each of the multiple
modular thermoelectric subsystems 1110 is a modular thermoelectric
subsystem 900. In another example, the multiple modular
thermoelectric subsystems 1110 are multiple modular thermoelectric
subsystems 900 stacking along the third direction 563. In yet
another example, a combined outlet component 929 of a modular
thermoelectric subsystem 900 is electrically connected to a
combined inlet component 921 of another modular thermoelectric
subsystem 900, and the multiple modular thermoelectric subsystems
900 are electrically connected in series.
[0144] In one embodiment, multiple modular thermoelectric
subsystems 1110 (e.g., five modular thermoelectric subsystems 900)
include multiple cold-fluid fans and/or pumps 1151 (e.g., five fan
or pump structures) that are installed at the opening of multiple
duct structures 1153 (e.g., five duct structure 940) for driving
the cold fluid flows through the cold channels along the second
direction 562. For example, the cold fluid flows then move out of
the multiple modular thermoelectric subsystems 1110 via multiple
duct structures 1155 (e.g., five duct structures). In another
example, the multiple cold-fluid fans and/or pumps 1151 and/or the
multiple duct structures 1153 are the one or more perimeter parts
of the thermoelectric system 1100, and through the one or more
perimeter parts, the cold fluid flows enter into the cold channels
along the second direction 562. In yet another example, the hot
fluid flows (e.g., hot air) move upward (e.g., from a chimney)
through all of the hot channels along the first direction 561.
[0145] In another embodiment, the multiple modular thermoelectric
subsystems 1110 (e.g., five modular thermoelectric subsystems 900)
include multiple hot-exhaust fans and/or pumps (e.g., five
hot-exhaust fans and/or pumps) that are installed at the opening of
multiple combined outlet components (e.g., five combined outlet
components 919) for maintaining a desired flow rate for all of the
hot fluid flows along the first direction 561 (e.g., from a
chimney). For example, the hot fluid flows then move out of the
multiple modular thermoelectric subsystems 1110 via multiple
combined outlet components (e.g., five combined outlet components
919).
[0146] In yet another embodiment, the thermoelectric system 1100
includes two main electrical leads that connect all the
thermoelectric device components (e.g., all the thermoelectric
device components 531 and 532) of the thermoelectric system 1100 in
order to output the electrical energy that is converted from the
thermal energy (e.g., the thermal energy from the waste heat in the
hot air flowing out a chimney). For example, the multiple modular
thermoelectric subsystems 900 are electrically connected in series.
In another example, one of the two main electrical leads is a
combined inlet component 921 of an end modular thermoelectric
subsystem 900, and the one of the two main electrical leads is a
combined outlet component 929 of the other end modular
thermoelectric subsystem 900.
[0147] FIGS. 13A-13B are simplified diagrams showing a heat
recovery system including the thermoelectric system 1100 according
to one embodiment of the present invention. These diagrams are
merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications.
[0148] According to some embodiments, the thermoelectric system
1100 is used in a heat recovery system 1200, and the thermoelectric
system 1100 includes multiple modular thermoelectric subsystems
1110. In one embodiment, the multiple modular thermoelectric
subsystems 1110 (e.g., five modular thermoelectric subsystems 900)
include multiple hot-exhaust fans and/or pumps 1261 (e.g., five
hot-exhaust fans and/or pumps 1261) that are installed at the
opening of multiple combined outlet components (e.g., five combined
outlet components 919) for maintaining a desired flow rate for all
of the hot fluid flows along the first direction 561 (e.g., from a
chimney). For example, the hot fluid flows then move out of the
multiple modular thermoelectric subsystems 1110 via multiple
combined outlet components (e.g., five combined outlet components
919). In another example, the multiple hot-exhaust fans and/or
pumps 1261 each are a belt-driven vane axial fan or pump. In yet
another example, the multiple hot-exhaust fans and/or pumps 1261
each are individually controlled (e.g., through variable-frequency
drive (VFD)) to handle uneven flows across the multiple combined
outlet components (e.g., the five combined outlet components
919).
[0149] As shown in FIGS. 13A-13B, one or more control dampers 1212
are disposed below multiple combined inlet components (e.g., five
combined inlet components 911). For example, the one or more
control dampers 1212 are used to maintain a controlled flow rate
for the hot fluid (e.g., hot air) through the hot channels. In
another example, the one or more control dampers 1212 are connected
to a chimney transition duct 1211.
[0150] In one embodiment, the chimney transition duct 1211 is part
of an extension duct structure 1215, which is also used to support
the thermoelectric system 1100. For example, the extension duct
structure 1215 also includes a bypass duct for providing a pathway
for exhausting over flows of the hot fluid. In another example, the
chimney transition duct 1211 is connected to an existing chimney
1210 via a mating flange 1213. In another embodiment, an access
platform 1280 is attached to the extension duct structure 1215 in
order to perform maintenance and/or repairs. For example, a ladder
1281 from roof is used to lead a person up to the access platform
1280.
[0151] FIG. 14 is a simplified diagram showing a thermoelectric
system according to another embodiment of the present invention.
This diagram is merely an example, which should not unduly limit
the scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications.
[0152] As shown in FIG. 14, the thermoelectric system 1300 includes
multiple modular thermoelectric subsystems 1310 (e.g., four modular
thermoelectric subsystems 1110) and multiple modular thermoelectric
subsystems 1320 (e.g., four modular thermoelectric subsystems
1110). For example, each of the multiple modular thermoelectric
subsystems 1310 is a modular thermoelectric subsystem 900, and each
of the multiple modular thermoelectric subsystems 1320 is a modular
thermoelectric subsystem 900. In another example, the multiple
modular thermoelectric subsystems 1310 are multiple modular
thermoelectric subsystems 900 stacking along the third direction
563, and the multiple modular thermoelectric subsystems 1320 are
multiple modular thermoelectric subsystems 900 stacking along the
third direction 563. In yet another example, a combined outlet
component 929 of a modular thermoelectric subsystem 1310 is
electrically connected to a combined inlet component 921 of another
modular thermoelectric subsystem 1310, and the multiple modular
thermoelectric subsystems 1310 are electrically connected in
series. In yet another example, a combined outlet component 929 of
a modular thermoelectric subsystem 1320 is electrically connected
to a combined inlet component 921 of another modular thermoelectric
subsystem 1320, and the multiple modular thermoelectric subsystems
1320 are electrically connected in series.
[0153] In one embodiment, multiple modular thermoelectric
subsystems 1310 (e.g., four modular thermoelectric subsystems 900)
include multiple cold-fluid fans and/or pumps 1351 (e.g., four fan
or pump structures) that are installed at the opening of multiple
duct structures 1353 (e.g., four duct structure 940) for driving
the cold fluid flows through the cold channels along the second
direction 562. For example, the cold fluid flows then move out of
the multiple modular thermoelectric subsystems 1310 via multiple
duct structures 1355 (e.g., four duct structures). In another
example, the multiple cold-fluid fans and/or pumps 1351 and/or the
multiple duct structures 1353 are the one or more perimeter parts
of the thermoelectric system 1300, and through the one or more
perimeter parts, the cold fluid flows enter into the cold channels
along the second direction 562.
[0154] In another embodiment, multiple modular thermoelectric
subsystems 1320 (e.g., four modular thermoelectric subsystems 900)
include multiple cold-fluid fans and/or pumps 1352 (e.g., four fan
or pump structures) that are installed at the opening of multiple
duct structures 1354 (e.g., four duct structure 940) for driving
the cold fluid flows through the cold channels in a direction
opposite to the second direction 562. For example, the cold fluid
flows then move out of the multiple modular thermoelectric
subsystems 1320 via multiple duct structures 1356 (e.g., four duct
structures). In another example, the multiple cold-fluid fans
and/or pumps 1352 and/or the multiple duct structures 1354 are the
one or more perimeter parts of the thermoelectric system 1300, and
through the one or more perimeter parts, the cold fluid flows enter
into the cold channels in a direction opposite to the second
direction 562.
[0155] In yet another embodiment, the hot fluid flows (e.g., hot
air) move upward (e.g., from a chimney) through all of the hot
channels of the multiple modular thermoelectric subsystems 1310 and
1320 along the first direction 561. In yet another embodiment, the
multiple modular thermoelectric subsystems 1310 (e.g., four modular
thermoelectric subsystems 900) include multiple hot-exhaust fans
and/or pumps (e.g., four hot-exhaust fans and/or pumps) that are
installed at the opening of multiple combined outlet components
(e.g., four combined outlet components 919) for maintaining a
desired flow rate for the hot fluid flows along the first direction
561 (e.g., from a chimney). For example, the hot fluid flows then
move out of the multiple modular thermoelectric subsystems 1310 via
multiple combined outlet components (e.g., four combined outlet
components 919). In yet another embodiment, the multiple modular
thermoelectric subsystems 1320 (e.g., four modular thermoelectric
subsystems 900) include multiple hot-exhaust fans and/or pumps
(e.g., four hot-exhaust fans and/or pumps) that are installed at
the opening of multiple combined outlet components (e.g., four
combined outlet components 919) for maintaining a desired flow rate
for the hot fluid flows along the first direction 561 (e.g., from
the chimney). For example, the hot fluid flows then move out of the
multiple modular thermoelectric subsystems 1320 via multiple
combined outlet components (e.g., four combined outlet components
919).
[0156] In yet another embodiment, the thermoelectric system 1300
includes two main electrical leads that connect all the
thermoelectric device components (e.g., all the thermoelectric
device components 531 and 532) of the thermoelectric system 1300 in
order to output the electrical energy that is converted from the
thermal energy (e.g., the thermal energy from the waste heat in the
hot gas flowing out a chimney). For example, the multiple modular
thermoelectric subsystems 900 are electrically connected in series.
In another example, one of the two main electrical leads is a
combined inlet component 921 of an end modular thermoelectric
subsystem 1310, and the one of the two main electrical leads is a
combined outlet component 929 of an end modular thermoelectric
subsystem 1320. In yet another example, a combined outlet component
929 of the other end modular thermoelectric subsystem 1310 is
electrically connected to a combined inlet component 921 of the
other end modular thermoelectric subsystem 1320.
[0157] As discussed above and further emphasized here, FIGS. 12 and
14 are merely examples, which should not unduly limit the scope of
the claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. For example, the
thermoelectric system 1100 includes only one modular thermoelectric
subsystems 1110. In another example, the thermoelectric system 1100
includes only one modular thermoelectric unit 901. In yet another
example, the thermoelectric system 1300 includes only one modular
thermoelectric subsystem 1310 and only one modular thermoelectric
subsystem 1320. In yet another example, the thermoelectric system
1300 includes only two modular thermoelectric units 901.
[0158] As shown in FIGS. 2B-2C, FIG. 3B, FIG. 4B, FIG. 10, FIG.
11A-11B, FIG. 12, and/or FIG. 14, a thermoelectric system includes
a number of repeated modular thermoelectric units and/or a number
of repeated modular thermoelectric subsystems according to certain
embodiments. For example, a modular thermoelectric unit includes a
plurality of hot-side heat exchangers, a plurality of cold-side
heat exchangers, and a plurality of thermoelectric device
components, all of which can be arranged in various permutations to
create an optimized system for a variety of exhaust temperatures
and flow rates. In another example, a modular thermoelectric
subsystem includes a plurality of hot-side heat exchangers, a
plurality of cold-side heat exchangers, and a plurality of
thermoelectric device components, all of which can be arranged in
various permutations to create an optimized system for a variety of
exhaust temperatures and flow rates.
[0159] FIGS. 15A-15B are simplified diagrams showing a heat
recovery system including the thermoelectric system 1300 according
to another embodiment of the present invention. These diagrams are
merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications.
[0160] According to some embodiments, the thermoelectric system
1300 is used in a heat recovery system 1400, and the thermoelectric
system 1300 includes multiple modular thermoelectric subsystems
1320. In one embodiment, the multiple modular thermoelectric
subsystems 1320 (e.g., four modular thermoelectric subsystems 900)
include multiple hot-exhaust fans and/or pumps 1462 (e.g., four
hot-exhaust fans and/or pumps 1462) that are installed at the
opening of multiple combined outlet components 1480 (e.g., four
combined outlet components 919) for maintaining a desired flow rate
for the hot fluid flows along the first direction 561 (e.g., from a
chimney). For example, the hot fluid flows then move out of the
multiple modular thermoelectric subsystems 1320 via multiple
combined outlet components 1480 (e.g., four combined outlet
components 919). In another example, the multiple hot-exhaust fans
and/or pumps 1462 each are a belt-driven vane axial fan or pump. In
yet another example, the multiple hot-exhaust fans and/or pumps
1462 each are individually controlled (e.g., through
variable-frequency drive (VFD)) to handle uneven flows across the
multiple combined outlet components (e.g., the four combined outlet
components 919).
[0161] According to certain embodiments, the multiple modular
thermoelectric subsystems 1310 (e.g., four modular thermoelectric
subsystems 900) include multiple hot-exhaust fans and/or pumps 1461
(e.g., four hot-exhaust fans and/or pumps 1461) that are installed
at the opening of multiple combined outlet components 1470 (e.g.,
four combined outlet components 919) for maintaining a desired flow
rate for the hot fluid flows along the first direction 561 (e.g.,
from a chimney). For example, the hot fluid flows then move out of
the multiple modular thermoelectric subsystems 1310 via multiple
combined outlet components 1470 (e.g., four combined outlet
components 919). In another example, the multiple hot-exhaust fans
and/or pumps 1461 each are a belt-driven vane axial fan or pump. In
yet another example, the multiple hot-exhaust fans and/or pumps
1461 each are individually controlled (e.g., through
variable-frequency drive (VFD)) to handle uneven flows across the
multiple combined outlet components (e.g., the four combined outlet
components 919).
[0162] As shown in FIGS. 15A-15B, one or more control dampers 1422
are disposed below multiple combined inlet components (e.g., four
combined inlet components 911) of the multiple modular
thermoelectric subsystems 1320, and one or more control dampers
1412 are disposed below multiple combined inlet components (e.g.,
four combined inlet components 911) of the multiple modular
thermoelectric subsystems 1310. For example, the one or more
control dampers 1412 and 1422 are used to maintain a controlled
flow rate for the hot fluid through the hot channels. In another
example, the one or more control dampers 1412 and 1422 are
connected to a chimney transition duct 1411.
[0163] In one embodiment, the chimney transition duct 1411 is part
of an extension duct structure 1415, which is also used to support
the thermoelectric system 1300. For example, the extension duct
structure 1415 also includes a bypass duct 1414 for providing a
pathway for exhausting over flows of the hot fluid. In another
example, the chimney transition duct 1411 is connected to an
existing chimney 1410 via a mating flange 1413. In another
embodiment, access platforms 1480 and 1490 are attached to the
extension duct structure 1415 in order to perform maintenance
and/or repairs. For example, ladders 1481 and 1491 from roof are
used to lead a person up to the access platforms 1480 and 1490
respectively.
[0164] As shown in FIGS. 15A-15B, the bypass duct 1414 is located
in a central region sided by the multiple duct structures 1355
(e.g., four duct structures) and the multiple duct structures 1356
(e.g., four duct structures). For example, the bypass duct 1414 is
connected to one or more control dampers 1424, which in turn are
connected to the chimney transition duct 1411. In another example,
the one or more control dampers 1412 and 1422 are closed, so that
the hot fluid does not flow into any hot channel of the multiple
modular thermoelectric subsystems 1310 and 1320, and the one or
more control dampers 1424 are open so that the hot fluid flows into
the bypass duct 1414.
[0165] As discussed above and further emphasized here, FIG. 10,
FIGS. 11A-11B, FIG. 12, FIGS. 13A-13B, FIG. 14, and FIGS. 15A-15B
are merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. For example, the
number of modular thermoelectric units for a modular thermoelectric
subsystem can be customized based on specific applications. In
another example, the number of modular thermoelectric subsystems
for a thermoelectric system can be customized based on specific
applications. In yet another example, for high temperature fluid
flows, a larger number of modular thermoelectric units in a
thermoelectric system can be arranged to leave sufficient space for
cooling in order to reduce the temperature that the hot channels
have to handle.
[0166] FIGS. 16A-16B are simplified diagrams showing a heat
recovery system including the thermoelectric system 1300 according
to yet another embodiment of the present invention. These diagrams
are merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications.
[0167] According to some embodiments, the thermoelectric system
1300 is used in a heat recovery system 1500, and the thermoelectric
system 1300 includes multiple modular thermoelectric subsystems
1320. In one embodiment, the multiple modular thermoelectric
subsystems 1320 (e.g., multiple modular thermoelectric subsystems
900) include multiple hot-exhaust fans and/or pumps 1562 that are
installed at the opening of multiple combined outlet components
1580 (e.g., multiple combined outlet components 919) for
maintaining a desired flow rate for the hot fluid flows along the
first direction 561 (e.g., from a chimney). For example, the hot
fluid flows then move out of the multiple modular thermoelectric
subsystems 1320 via multiple combined outlet components 1580 (e.g.,
multiple combined outlet components 919). In another example, the
multiple hot-exhaust fans and/or pumps 1562 each are a belt-driven
vane axial fan or pump. In yet another example, the multiple
hot-exhaust fans and/or pumps 1562 each are individually controlled
(e.g., through variable-frequency drive (VFD)) to handle uneven
flows across the multiple combined outlet components (e.g., the
multiple combined outlet components 919).
[0168] According to certain embodiments, the multiple modular
thermoelectric subsystems 1310 (e.g., multiple modular
thermoelectric subsystems 900) include multiple hot-exhaust fans
and/or pumps 1561 that are installed at the opening of multiple
combined outlet components 1570 (e.g., multiple combined outlet
components 919) for maintaining a desired flow rate for the hot
fluid flows along the first direction 561 (e.g., from a chimney).
For example, the hot fluid flows then move out of the multiple
modular thermoelectric subsystems 1310 via multiple combined outlet
components 1570 (e.g., multiple combined outlet components 919). In
another example, the multiple hot-exhaust fans and/or pumps 1561
each are a belt-driven vane axial fan or pump. In yet another
example, the multiple hot-exhaust fans and/or pumps 1561 each are
individually controlled (e.g., through variable-frequency drive
(VFD)) to handle uneven flows across the multiple combined outlet
components (e.g., the multiple combined outlet components 919).
[0169] As shown in FIGS. 16A-16B, one or more valves (e.g., valves
1530 and 1532) are disposed below a supply duct 1520 and multiple
combined inlet components (e.g., multiple combined inlet components
911) of the multiple modular thermoelectric subsystems 1320, and
one or more valves (e.g., valves 1534 and 1536) are disposed below
a supply duct 1510 and multiple combined inlet components (e.g.,
multiple combined inlet components 911) of the multiple modular
thermoelectric subsystems 1310. For example, the one or more valves
(e.g., the valves 1530, 1532, 1534, and 1536) are used to control a
flow rate for the hot fluid through the hot channels. In another
example, the one or more valves (e.g., the valves 1530, 1532, 1534,
and 1536) are connected to a chimney transition duct 1511.
[0170] In one embodiment, the chimney transition duct 1511 is part
of an extension duct structure, which is also used to support the
thermoelectric system 1300. For example, the extension duct
structure also includes a bypass duct 1514 for providing a pathway
for exhausting over flows of the hot fluid. In another example, the
chimney transition duct 1511 is connected to an existing chimney
via a mating flange. In another embodiment, one or more access
platforms are attached to the extension duct structure in order to
perform maintenance and/or repairs. For example, one or more
ladders from roof are used to lead a person up to the one or more
access platforms respectively.
[0171] According to one embodiment, the bypass duct 1514 is located
in a central region sided by the multiple duct structures 1355 and
1356 and two exhaust ducts 1516 and 1526. For example, the exhaust
duct 1516 is parallel or substantially parallel with the bypass
duct 1514. In another example, the exhaust duct 1526 is parallel or
substantially parallel with the bypass duct 1514. In another
example, the bypass duct 1514 is connected to one or more valves
(e.g., the valves 1532 and 1534), which in turn are connected to
the chimney transition duct 1511.
[0172] In one embodiment, as shown in FIG. 16A, the valves 1530,
1532, 1534, and 1536 are arranged so that the hot fluid flows into
the hot channels of the multiple modular thermoelectric subsystems
1310 through the supply duct 1510 and flows into the hot channels
of the multiple modular thermoelectric subsystems 1320 through the
supply duct 1520, but the hot fluid does not flow into the bypass
duct 1514. In another embodiment, as shown in FIG. 16B, the valves
1530, 1532, 1534, and 1536 are arranged so that the hot fluid does
not flow into any of the supply ducts 1510 and 1520 and does not
flow into any hot channel of the multiple modular thermoelectric
subsystems 1310 and 1320, but the hot fluid flows into the bypass
duct 1514.
[0173] According to another embodiment, the multiple modular
thermoelectric subsystems 1310 (e.g., multiple modular
thermoelectric subsystems 900) include the multiple cold-fluid fans
and/or pumps 1351 that are installed at the opening of the multiple
duct structures 1353 for driving the cold fluid flows from a supply
duct 1518 through the cold channels along the second direction 562.
For example, the cold fluid flows then move out of the multiple
modular thermoelectric subsystems 1310 via the multiple duct
structures 1355 into an exhaust duct 1516. In another embodiment,
the multiple modular thermoelectric subsystems 1320 (e.g., multiple
modular thermoelectric subsystems 900) include the multiple
cold-fluid fans and/or pumps 1352 that are installed at the opening
of the multiple duct structures 1354 for driving the cold fluid
flows from a supply duct 1524 through the cold channels in a
direction opposite to the second direction 562. For example, the
cold fluid flows then move out of the multiple modular
thermoelectric subsystems 1320 via the multiple duct structures
1356 into an exhaust duct 1526. In yet another embodiment, the hot
fluid flows (e.g., hot air) move upward (e.g., from a chimney)
through all of the hot channels of the multiple modular
thermoelectric subsystems 1310 and 1320 along the first direction
561.
[0174] As discussed above and further emphasized here, FIGS.
16A-16B are merely examples, which should not unduly limit the
scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications. For
example, the cold fluid flows move out of the multiple modular
thermoelectric subsystems 1320 via the multiple duct structures
1356 into the bypass duct 1514 instead of the exhaust duct 1526. In
another example, the cold fluid flows move out of the multiple
modular thermoelectric subsystems 1310 via the multiple duct
structures 1355 into the bypass duct 1514 instead of the exhaust
duct 1516. In yet another example, the valves 1530, 1532, 1534, and
1536 are removed so that the supply ducts 1510 and 1520 each are
connected to the chimney transition duct 1511 without through any
valve and the bypass duct 1514 is also connected to the chimney
transition duct 1511 without through any valve, and the bypass duct
1514 shares a movable sidewall with the supply duct 1520 and shares
another movable sidewall with the supply duct 1510, as shown in
FIGS. 17A-17B.
[0175] FIGS. 17A-17B are simplified diagrams showing the bypass
duct 1514 and the supply ducts 1510 and 1520 as parts of a heat
recovery system including the thermoelectric system 1300 according
to yet another embodiment of the present invention. These diagrams
are merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications.
[0176] According to some embodiments, the bypass duct 1514 and the
supply ducts 1510 and 1520 are parts of a heat recovery system
1600. According to certain embodiments, the heat recovery system
1600 also uses the thermoelectric system 1300 similar to the
arrangement as shown in FIGS. 16A-16B. In one embodiment, the
supply ducts 1510 and 1520 each are connected to the chimney
transition duct 1511 without through any valve, and the bypass duct
1514 is also connected to the chimney transition duct 1511 without
through any valve. For example, the supply duct 1520 includes two
sidewalls 1630 and 1632, and the supply duct 1510 includes two
sidewalls 1634 and 1636. In another example, the bypass duct 1514
shares the sidewall 1632 with the supply duct 1520, and shares the
sidewall 1634 with the supply duct 1510. In yet another example,
the sidewalls 1632 and 1634 are movable.
[0177] As shown in FIG. 17A, the sidewalls 1630, 1632, 1634, and
1636 are arranged so that the hot fluid flows from the chimney
transition duct 1511 through the supply duct 1510 (e.g., into the
hot channels of the multiple modular thermoelectric subsystems
1310), and flows from the chimney transition duct 1511 through the
supply duct 1520 (e.g., into the hot channels of the multiple
modular thermoelectric subsystems 1320), but the hot fluid does not
flow into the bypass duct 1514 from the chimney transition duct
1511, according to one embodiment. As shown in FIG. 17B, the
sidewalls 1630, 1632, 1634, and 1636 are arranged so that the hot
fluid does not flow into any of the supply ducts 1510 and 1520 from
the chimney transition duct 1511, but the hot fluid flows into the
bypass duct 1514 from the chimney transition duct 1511.
[0178] According to another embodiment, the multiple modular
thermoelectric subsystems 1310 (e.g., multiple modular
thermoelectric subsystems 900) include the multiple cold-fluid fans
and/or pumps 1351 that are installed at the opening of the multiple
duct structures 1353 for driving the cold fluid flows from the
supply duct 1518 through the cold channels along the second
direction 562. For example, the cold fluid flows then move out of
the multiple modular thermoelectric subsystems 1310 via the
multiple duct structures 1355 into an exhaust duct 1516. In another
embodiment, the multiple modular thermoelectric subsystems 1320
(e.g., multiple modular thermoelectric subsystems 900) include the
multiple cold-fluid fans and/or pumps 1352 that are installed at
the opening of the multiple duct structures 1354 for driving the
cold fluid flows from a supply duct 1524 through the cold channels
in a direction opposite to the second direction 562. For example,
the cold fluid flows then move out of the multiple modular
thermoelectric subsystems 1320 via the multiple duct structures
1356 into an exhaust duct 1526. In yet another embodiment, the hot
fluid flows (e.g., hot air) move upward (e.g., from a chimney)
through all of the hot channels of the multiple modular
thermoelectric subsystems 1310 and 1320 along the first direction
561.
[0179] As shown in FIGS. 16A-16B and/or FIGS. 17A-17B, a bypass
chimney (e.g., the bypass duct 1514) is used to divert a hot
exhaust flow around the thermoelectric system 1300 if the heat
recovery system is offline according to some embodiments. In one
embodiment, one or more valves (e.g., the valves 1530, 1532, 1534
and 1536) are also used. In another embodiment, one or more
moveable diverter vanes (e.g., the sidewalls 1630, 1632, 1634, and
1636) can direct the hot exhaust flow to the thermoelectric system
1300 or to the bypass chimney (e.g., the bypass duct 1514). For
example, the one or more moveable diverter vanes are located below
(e.g., immediately or remotely upstream of the thermoelectric
system 1300). In another example, the one or more moveable diverter
vanes include one or more vanes per flow path.
[0180] In yet another embodiment, to reduce the footprint of the
heat recovery system, the multiple modular thermoelectric
subsystems 1310 and 1320 are positioned on the perimeter of the
bypass chimney with the cold fluid flows that enter from the
exterior of the heat recovery system from multiple cold-fluid fans
and/or pumps (e.g., the multiple cold-fluid fans and/or pumps 1351
or 1352) and/or one or more supply ducts (e.g., the supply ducts
1514 and 1524) and are discharged into center of the heat recovery
system. For example, the discharge of the cold fluid flows enter
the bypass chimney (e.g., the bypass duct 1514). In another
example, the discharge of the cold fluid flows enter one or more
exhaust ducts (e.g., the exhaust ducts 1516 and 1526) that run
parallel to the bypass chimney (e.g., the bypass duct 1514).
[0181] Referring to FIG. 1, in the conventional thermoelectric
generation system (e.g., the conventional heat recovery system
4000), the one or more thermoelectric device components 4010 are
separated from hot fluid molecules of the one or more hot fluid
flows 4042 by a significant distance with large thermal resistance.
Therefore, little of the available thermal energy in the one or
more hot fluid flows 4042 is transferred to the one or more
thermoelectric device components 4010, and the temperature gradient
across the one or more thermoelectric device components 4010 is
degraded according to some embodiments.
[0182] FIG. 18 is a simplified diagram showing a heat recovery
system as shown in FIGS. 13A-13B, FIGS. 15A-15B, FIGS. 16A-16B,
and/or FIGS. 17A-17B according to some embodiments of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications.
[0183] As shown, in a heat recovery system 5000, one or more
thermoelectric device components 5010 are within a hot flow region
5040. In one embodiment, one or more hot junctions and one or more
cold junctions are generated by allowing a hot flow pathway to be
sandwiched between cold flow pathways 5082 through the one or more
thermoelectric device components 5010. For example, one or more hot
fluid flows 5042 moves upward out of an exhaust pipe or a chimney
5044, and the thermoelectric system 5090 is placed across
substantially the entire cross-sectional area of the exhaust pipe
or the chimney 5044. In another example, the hot flow pathway is
modified to one or more restricted channels 5080 in the vertical
direction (e.g., out of the exhaust pipe or the chimney 5044). In
yet another example, a hot fluid flow is separated into multiple
hot fluid flows received by multiple restricted channels 5080
respectively.
[0184] According to one embodiment, the hot channels are sandwiched
by one or more cold channels along a horizontal direction (e.g.,
from right to left), allowing one or more cold fluid flows (e.g.,
the cold fluid guided by directional funnels) to pass through. For
example, between the corresponding hot and cold channels, the one
or more thermoelectric device components are installed to stay
right in the middle of the cross-sectional area of the exhaust pipe
or the chimney 5044. According to another embodiment, such layout
of the heat recovery system allows the one or more thermoelectric
device components 5010 to be in substantially direct interaction
with molecules of the one or more hot fluid flows 5042 because the
hot channels directly serve as heat exchangers to deliver thermal
energy carried by the one or more hot fluid flows 5042. For
example, the one or more cold fluid flows 5082 through the cold
channels still steadily provides cooling to the cold front of the
thermoelectric device components 5010, which can be maintained with
much greater temperature gradient with much improved stability. In
another example, the thermoelectric device components 5010 in such
heat recovery system can be designed with high thermoelectric power
density for adapting the high-gradient thermal junctions with large
thermal stress and is able to generate more electric power from
waste heat with much improved efficiency.
[0185] According to yet another embodiment, one or more modular
thermoelectric units are designed to include a hot-side heat
exchanger separately disposed and sandwiched between two cold-side
heat exchangers. The hot-side heat exchanger includes more than one
hot channels disposed in parallel for conveying hot fluid flows in
a first direction and aligned separately in a second direction with
a gap between each other. Each of the two cold-side heat exchangers
includes a continuous contact plate to commonly couple the two or
more hot channels in the second direction for conveying a cold
fluid flows. The hot-cold channel configuration leads to two
thermal junctions for inserting two thermoelectric devices (e.g.,
two thermoelectric device components). The matching dimensions of
inlet and outlet regions of the hot channels and side-to-side
distance between two cold channels provide a modular unit capable
of scaling up in a third direction that is perpendicular to both
the first direction and the second direction.
[0186] According to yet another embodiment, a modular unit
convenient for assembling to a system for various applications
including power generation from waste heat is provided. The modular
unit includes a simplified cuboid outline convenient for stacking
each other along at least two directions. Additionally, the modular
unit includes at least a hot channel for conveying heated flows and
a cold channel for conveying cooling flows, maintaining a junction
with substantially stable temperature gradient. The modular unit
further includes at least a thermoelectric device (e.g., a
thermoelectric device component) sandwiched between the hot channel
and the cold channel and configured to generate electrical power by
utilizing the temperature gradient across the junction.
Furthermore, the modular unit is configured to align the hot
channel in a first direction and the cold channel in a second
direction, the second direction is either a direction opposite or
the same to the first direction or a direction perpendicular to the
first direction. Moreover, the modular unit is configured to be
stacked along the first direction and the second direction and
additionally a third direction, the third direction being
perpendicular to both the first direction and the second
direction.
[0187] According to yet another embodiment, a modular
thermoelectric unit configured for forming a system for various
thermoelectric heat recovery applications is provided. The modular
unit includes a first heat exchanger including two or more first
channels, each being configured for conveying heated fluid flows in
a first direction and each being disposed in parallel near each
other along a second direction. The second direction is
perpendicular to the first direction. The module unit further
includes two second heat exchangers respectively comprising a
second channel and a third channel disposed in parallel for
conveying cooling fluid flows in the second direction. Each and
every first channel is configured to at least have a middle region
completely disposed between a first contact face of the second
channel and a third contact face of the third channel. The second
channel is configured to have a second contact face facing a third
direction that is perpendicular to both the first direction and the
second direction. The third channel is substantially the same as
the second channel and configured to have a fourth contact face
facing a fourth direction that is opposite to the third direction.
The modular unit additionally contains a first thermoelectric
device (e.g., a thermoelectric device component) sandwiched between
the first contact face and the first side of the first channel and
a second thermoelectric device (e.g., a thermoelectric device
component) sandwiched between the third contact face and the second
side of the first channel. The second thermoelectric device is
configured to be electrically coupled to the first thermoelectric
device. The modular unit further includes at least one first
electrical lead coupled to the first thermoelectric device and at
least one second electrical lead coupled to the second
thermoelectric device.
[0188] According to yet another embodiment, the modular unit
includes a first thermal interface material disposed between the
first or second side of the first channel and a hot side of the
first or second thermoelectric device, respectively. Furthermore,
the modular unit includes a second thermal interface material
disposed between the first or third contact face of the second or
third channel and a cold side of the first or second thermoelectric
device, respectively. In a specific embodiment, the second or third
channel is held fixed with the first or second side of each first
channel by bolts, compressed from the cold side to the hot side,
allowing good thermal contacts to be formed between hot or cold
side of the thermoelectric device respectively with corresponding
contact faces of the first or second heat exchangers. The
thermoelectric devices are configured to convert a thermal gradient
into electrical energy as one of solutions for recovering waste
heat. Moreover, the modular unit includes an insulation material
disposed at any contact regions between the first channel and the
second or third channel respectively.
[0189] According to yet another embodiment, the first channel
includes a first transition region (e.g., a transition component)
connecting an inlet region (e.g., an inlet component) with the
middle region (e.g., a middle component) and a second transition
region (e.g., a transition component) connecting an outlet region
(e.g., an outlet component) with the middle region (e.g., a middle
component). The first transition region and the second transition
region are ducts substantially similar in shape with a reduced
cross section from the inlet or outlet region towards the middle
region respectively. In a specific embodiment, the inlet or outlet
region has a rectangular shaped cross section with a length being
aligned in the second direction and a width in the third direction
defining a module width of the modular unit. The module width is
configured to substantially equal to a distance from the second
contact face of the second channel and the fourth contact face of
the third channel. In yet another specific embodiment, the modular
unit has a module length that is a multiplication of the length of
the inlet or outlet region of the first channel plus any gaps
between two neighboring first channels. The module length is
substantially equal to a length of the second channel or the third
channel along the second direction.
[0190] According to yet another embodiment, a subsystem for heat
recovery is provided. The subsystem is stacked from a plurality of
modular units. Each modular unit includes a first heat exchanger
disposed between two substantially identical second heat
exchangers. The first heat exchanger includes at least a first
channel in a first direction configured for passing fluid flows at
a first temperature and the two second heat exchangers respectively
include a second channel and a third channel, both in a second
direction configured for passing fluid flows at a second
temperature. The second direction is perpendicular to the first
direction and the second temperature is lower than the first
temperature. The first channel includes at least a middle region
having a first side plate and a second side plate disposed in
parallel to the second direction and configured to respectively
couple a first thermoelectric device and a second thermoelectric
device (e.g., substantially the same as the first thermoelectric
device). The first or second thermoelectric device includes a
hot-side terminal forming thermal contact with the first or second
side plate of the first channel and a cold-side terminal forming
thermal contact with a first or third contact face of the second or
third channel respectively. The second or third channel includes a
second or fourth contact face that faces outside in or opposite to
a third direction that is perpendicular to both the first direction
and the second direction. The modular unit is configured to dispose
the second channel to contact the third channel of a neighboring
modular unit to form a first common inlet region (e.g., a combined
inlet component) and a first common outlet region (e.g., a combined
outlet component) as the plurality of the modular units is stacked
along the third direction. The modular unit is further configured
to dispose all the first channels to form a second common inlet
region and a second common outlet region as the plurality of the
modular units is stacked along the third direction.
[0191] According to yet another embodiment, the subsystem includes
an exhaust fan or pump coupled to the second common outlet region
for maintaining a flow rate of the fluid flows at the first
temperature. Each first channel includes a plurality of fin
structures disposed at least in the middle region aligned in the
first direction for enhancing thermal contact area for facilitating
heat transfer from the fluid flows at the first temperature to the
hot-side terminal of the first thermoelectric device. Each of the
second channel and the third channel also includes a plurality of
fin structures aligned in the second direction for enhancing
thermal contact area for facilitating heat transfer from the
cold-side terminal to the fluid flows at the second temperature.
Depending on system preference, the subsystem includes a first
frame structure to hold the plurality of modular units stacked
together and allow individual modular unit to be removed or
replaced. Furthermore, the subsystem optionally includes a second
frame structure configured to hold the first frame structure and to
allow the first frame structure being slide out of the second frame
structure partially so that maintenance or replacement work can be
performed to any or all modular units therein.
[0192] According to yet another embodiment, a method is provided
for making the modular thermoelectric unit configured to be
assembled to a subsystem for converting waste heat to useful
energy. The method includes providing a first heat exchanger
containing two or more first channels for conveying hot fluid flows
in a first direction. The two or more first channels are configured
to be aligned along a second direction to make contact plates on
opposite sides of each first channel to be leveled respectively.
The second direction is perpendicular to the first direction. The
method further includes providing two thermoelectric devices (e.g.,
two thermoelectric device components) each having a hot-side
terminal and a cold-side terminal. Additionally, the method
includes respectively attaching the two hot-side terminals to
contact with the two leveled contact plates on opposite sides of
each first channel. The method further includes providing two
second heat exchangers each including a second channel along the
second direction for conveying cold fluid flows. Furthermore, the
method includes disposing the two second heat exchangers by
coupling each second channel respectively to the cold-side terminal
of each of the two thermoelectric devices to have the two or more
first channels sandwiched by two thermal junctions.
[0193] According to yet another embodiment, the method includes
configuring the two or more first channels and the two second
channels to form a modular unit having a height defined by the
first channel and a length given by the second channel and a width
given by a distance between two outer plates of the two second
channels on opposite sides of the first channels. The modular unit
is capable of being stacked along a third direction by binding a
second channel of one modular unit with another second channel of a
neighboring modular unit to form a subsystem. The third direction
is perpendicular to both the first direction along the first
channel and the second direction along the second channel.
Additionally, the modular unit can be scaled up in length by
coupling with another modular unit along the second direction to
connect the second channels of one unit to the second channels of
another unit.
[0194] Depending on various embodiments, one or more benefits can
be achieved with the modular design of heat recovery system.
Certain embodiments of the present invention provide a
thermoelectric modular design that allows a wide range of heat
resources to be exploited with a single design, thus allowing for
high volume, low cost manufacturing of modules scalable for a
variety of systems in applications of heat recovery, thermoelectric
power generation, and/or thermoelectric cooling. Some embodiments
of the present invention provide, for the scalable modular heat
recovery unit, enhanced thermal contact area via a continuous cold
sink to couple with heat sinks from two or more stacked hot fluid
channels in perpendicular direction, thus reducing the cost,
avoiding complex electrical and hydraulic connections, and
improving the mechanical structural integrity of the thermoelectric
module (e.g., a modular thermoelectric unit). Certain embodiments
of the present invention can keep the cold sinks at two outside
positions so that the bolts for coupling them can be kept cool,
while reducing thermal loss and eliminating some materials by
keeping the hot fluid channel in the middle position. Some
embodiments of the present invention make it simple for assembling
the thermoelectric modular unit itself and stacking multiple
modular units together to form a mega module assembly or a
thermoelectric subsystem with desired dimensions and further being
capable of scaling up to form a customized heat recovery system.
For example, the thermoelectric subsystem needs one exhaust fan or
pump and one cooling fan or pump for multiple modular units, and
each modular unit in the subsystem is easily accessed for
maintenance and replacement. Certain embodiments of the present
invention utilize nanostructure-based thermoelectric devices with
enhanced thermoelectric efficiency and substantially reduced
manufacturing cost for various heat recovery applications including
industrial combustion processes.
[0195] According to another embodiment, an apparatus for generating
electricity includes one or more first components configured to
extract heat from at least a first fluid flow at a first
temperature to one or more devices configured to convert thermal
energy to electric energy. The first fluid flow is in a first
direction. Additionally, the apparatus includes one or more second
components configured to transfer heat from the one or more devices
to at least a second fluid flow at a second temperature. The second
temperature is lower than the first temperature, and the second
fluid flow is in a second direction. Each first part of the first
fluid flow corresponds to a first shortest distance to the one or
more devices, and the first shortest distance is less than half the
square root of the total free flow area for a corresponding first
cross-section of the first fluid flow. The first cross-section is
perpendicular to the first direction. Each second part of the
second fluid flow corresponds to a second shortest distance to the
one or more devices, and the second shortest distance is less than
half the square root of the total free flow area for a
corresponding second cross-section of the second fluid flow. The
second cross-section is perpendicular to the second direction. For
example, the apparatus is implemented according to at least FIGS.
6A-6D.
[0196] In another example, the first direction varies with movement
of the first fluid flow. In yet another example, the first
direction is fixed regardless of movement of the first fluid flow.
In yet another example, the second direction varies with movement
of the second fluid flow. In yet another example, the second
direction is fixed regardless of movement of the second fluid flow.
In yet another example, the one or more first components include a
first heat exchanger, and the one or more second components include
a second heat exchanger. In yet another example, the one or more
devices are one or more thermoelectric devices. In yet another
example, each of the one or more thermoelectric devices includes at
least one thermoelectric material.
[0197] According to yet another embodiment, a thermoelectric
apparatus includes one or more first channels configured to receive
one or more first parts of a first fluid flow at a first
temperature, and one or more second channels configured to receive
one or more parts of a second fluid flow at a second temperature.
The second temperature is lower than the first temperature.
Additionally, the apparatus includes one or more third channels
configured to receive one or more second parts of the first fluid
flow, and the one or more third channels are separated from the one
or more first channels by at least the one or more second channels.
Moreover, the apparatus includes one or more first thermoelectric
materials located between the one or more first channels and the
one or more second channels, and one or more second thermoelectric
materials located between the one or more second channels and the
one or more third channels. For example, the apparatus is
implemented according to at least FIGS. 2B-2C, FIGS. 3A-3B, FIG.
4B, FIG. 10, FIGS. 11A-11B, FIG. 12, FIG. 14, and/or FIG. 18.
[0198] In another example, the one or more first channels are one
or more parts of a first heat exchanger, the one or more second
channels are one or more parts of a second heat exchanger, and the
one or more third channels are one or more parts of a third heat
exchanger. The first heat exchanger and the third heat exchanger
are separated by at least the second heat exchanger. In yet another
example, the one or more first thermoelectric materials are located
between the first heat exchanger and the second heat exchanger, and
the one or more second thermoelectric materials are located between
the second heat exchanger and the third heat exchanger. In yet
another example, the one or more first channels are one or more
parts of a first heat exchanger. The one or more second channels
include multiple channels. At least one of the multiple channels is
at least a part of a second heat exchanger, and at least another
one of the multiple channels is at least a part of a third heat
exchanger. The one or more third channels are one or more parts of
a fourth heat exchanger. In yet another example, the first heat
exchanger and the fourth heat exchanger are separated by at least
the second heat exchanger and the third heat exchanger. In yet
another example, the second heat exchanger and the third heat
exchanger are in contact with each other. In yet another example,
the first heat exchanger and the second heat exchanger are parts of
a first modular thermoelectric unit, and the third heat exchanger
and the fourth heat exchanger are parts of a second modular
thermoelectric unit. In yet another example, the one or more first
thermoelectric materials are located between the first heat
exchanger and the second heat exchanger, and the one or more second
thermoelectric materials are located between the third heat
exchanger and the fourth heat exchanger. In yet another example,
the one or more first thermoelectric materials are not in direct
contact with the one or more first channels or the one or more
second channels, and the one or more second thermoelectric
materials are not in direct contact with the one or more second
channels or the one or more third channels. In yet another example,
the one or more second channels are further configured to receive
all parts of the second fluid flow.
[0199] According to yet another embodiment, a heat recovery system
includes a thermoelectric apparatus, a first duct coupled to the
thermoelectric apparatus, and a second duct not coupled to the
thermoelectric apparatus. The first duct and the second duct both
are connected to a third duct and configured to receive by the
first duct a first fluid flow at a first temperature from the third
duct if the second duct does not receive the first fluid flow and
to receive by the second duct the first fluid flow from the third
duct if the first duct does not receive the first fluid flow. The
thermoelectric apparatus is configured to receive at least a second
fluid flow at a second temperature. The second fluid flow moves
into the thermoelectric apparatus from one or more first perimeter
parts of the thermoelectric apparatus in a first direction. The
first direction is towards the second duct, and the second
temperature is lower than the first temperature. Also, the
thermoelectric apparatus is configured to discharge the second
fluid flow into a fourth duct, and the fourth duct is the second
duct or is substantially parallel with the second duct. For
example, the apparatus is implemented according to at least FIGS.
13A-13B, FIGS. 15A-15B, FIGS. 16A-16B, and/or FIGS. 17A-17B.
[0200] In another example, the thermoelectric apparatus is further
configured to receive at least a third fluid flow at the second
temperature. The third fluid flow moves into the thermoelectric
apparatus from one or more second perimeter parts of the
thermoelectric apparatus in a second direction, and the second
direction is towards the second duct. Also, the thermoelectric
apparatus is further configured to discharge the third fluid flow
into a fifth duct. The fifth duct is the second duct or is
substantially parallel with the second duct. In yet another
example, the second direction is opposite to the first direction.
In yet another example, the heat recovery system includes a fifth
duct coupled to the thermoelectric apparatus and connected to the
third duct. The fifth duct and the second duct are configured to
receive by the fifth duct a third fluid flow at the first
temperature from the third duct if the second duct does not receive
the third fluid flow and to receive by the second duct the third
fluid flow from the third duct if the fifth duct does not receive
the third fluid flow. In yet another example, the first duct and
the second duct share a first sidewall, and the second duct and the
fifth duct share a second sidewall. The first sidewall and the
second sidewall are configured to move to a first position and a
second position respectively in order to provide the first fluid
flow to the first duct but not to the second duct and in order to
provide the third fluid flow to the fifth duct but not to the
second duct. Also, the first sidewall and the second sidewall are
configured to move to a third position and a fourth position
respectively in order to provide the first fluid flow and the third
fluid flow to the second duct but not to the first duct and not to
the fifth duct, wherein the first fluid flow and the third fluid
flow are received by the second duct together as one fluid flow. In
yet another example, the thermoelectric apparatus is a
thermoelectric system. In yet another example, the first duct is a
first chimney, the second duct is a second chimney, and the third
duct is a third chimney. In yet another example, the thermoelectric
apparatus is further configured to discharge the second fluid flow
into the fourth duct through a fifth duct. In yet another example,
the thermoelectric apparatus is further configured to discharge the
second fluid flow into the fourth duct, and the fourth duct is
parallel with the second duct.
[0201] According to yet another embodiment, a thermoelectric
apparatus includes a first heat exchanger configured to transfer
heat to or extract heat from a first fluid flow at a first
temperature, and a second heat exchanger configured to extract heat
from or transfer heat to a second fluid flow at a second
temperature. The second temperature is different from the first
temperature. Additionally, the apparatus includes a third heat
exchanger configured to transfer heat to or extract heat from a
third fluid flow at the first temperature, and the third heat
exchanger is separated from the first heat exchanger by at least
the second heat exchanger. Moreover, the apparatus includes one or
more first thermoelectric materials sandwiched between the first
heat exchanger and the second heat exchanger, one or more second
thermoelectric materials sandwiched between the second heat
exchanger and the third heat exchanger, and one or more components
extending from the first heat exchanger to the third heat exchanger
without making any thermal contact with the second heat exchanger.
The one or more first thermoelectric materials, the second heat
exchanger, and the one or more second thermoelectric materials are
located between the first heat exchanger and the third heat
exchanger, and the one or more components are configured to apply
one or more compressive forces to at least the one or more first
thermoelectric materials, the second heat exchanger, and the one or
more second thermoelectric materials. For example, the apparatus is
implemented according to at least FIG. 9.
[0202] In another example, the one or more components are not in
any thermal contact with the one or more first thermoelectric
materials and are not in any thermal contact with the one or more
second thermoelectric materials. In yet another example, the second
temperature is higher than the first temperature. In yet another
example, the second temperature is lower than the first
temperature. In yet another example, the one or more first
thermoelectric materials are not in direct contact with the first
heat exchanger or the second heat exchanger, and the one or more
second thermoelectric materials are not in direct contact with the
second heat exchanger or the third heat exchanger. In yet another
example, the one or more components include one or more bolts
extending from the first heat exchanger to the third heat exchanger
without making any thermal contact with the second heat
exchanger.
[0203] According to yet another embodiment, a method for generating
electricity includes extracting heat from at least a first fluid
flow at a first temperature to one or more devices configured to
convert thermal energy to electric energy. The first fluid flow is
in a first direction. Additionally, the method includes
transferring heat to at least a second fluid flow at a second
temperature. The second temperature is lower than the first
temperature, and the second fluid flow is in a second direction.
Each first part of the first fluid flow corresponds to a first
shortest distance to the one or more devices, and the first
shortest distance is less than half the square root of the total
free flow area for a corresponding first cross-section of the first
fluid flow. The first cross-section is perpendicular to the first
direction. Each second part of the second fluid flow corresponds to
a second shortest distance to the one or more devices, and the
second shortest distance is less than half the square root of the
total free flow area for a corresponding second cross-section of
the second fluid flow. The second cross-section is perpendicular to
the second direction. For example, the method is implemented
according to at least FIGS. 6A-6D. In another example, the one or
more devices are one or more thermoelectric devices.
[0204] According to yet another embodiment, a thermoelectric method
for generating electricity includes receiving, by one or more first
channels, one or more first parts of a first fluid flow at a first
temperature, and receiving, by one or more second channels, one or
more parts of a second fluid flow at a second temperature. The
second temperature is lower than the first temperature.
Additionally, the method includes receiving, by one or more third
channels, one or more second parts of the first fluid flow. The one
or more third channels are separated from the one or more first
channels by at least the one or more second channels. Moreover, the
method includes generating electricity by at least one or more
first thermoelectric materials and one or more second
thermoelectric materials. The one or more first thermoelectric
materials are located between the one or more first channels and
the one or more second channels, and the one or more second
thermoelectric materials are located between the one or more second
channels and the one or more third channels. For example, the
method is implemented according to at least FIGS. 2B-2C, FIGS.
3A-3B, FIG. 4B, FIG. 10, FIGS. 11A-11B, FIG. 12, FIG. 14, and/or
FIG. 18.
[0205] According to yet another embodiment, a method for heat
recovery includes receiving, by a first duct, a first fluid flow at
a first temperature from a third duct connected to both the first
duct and a second duct if the second duct does not receive the
first fluid flow. The first duct is coupled to a thermoelectric
apparatus, and the second duct is not coupled to the thermoelectric
apparatus. Additionally, the method includes receiving, by the
second duct, the first fluid flow from the third duct if the first
duct does not receive the first fluid flow. Moreover, the method
includes receiving, by the thermoelectric apparatus, at least a
second fluid flow at a second temperature, and the second fluid
flow moves into the thermoelectric apparatus from one or more first
perimeter parts of the thermoelectric apparatus in a first
direction. The first direction is towards the second duct, and the
second temperature is lower than the first temperature. Also, the
method includes discharging, by the thermoelectric apparatus, the
second fluid flow into a fourth duct. The fourth duct is the second
duct or is substantially parallel with the second duct. For
example, the method is implemented according to at least FIGS.
13A-13B, FIGS. 15A-15B, FIGS. 16A-16B, and/or FIGS. 17A-17B.
[0206] According to yet another embodiment, a method for
thermoelectric conversion includes transferring heat to or
extracting heat from a first fluid flow at a first temperature by a
first heat exchanger, and extracting heat from or transferring heat
to a second fluid flow at a second temperature by a second heat
exchanger. The second temperature is different from the first
temperature. Additionally, the method includes transferring heat to
or extracting heat from a third fluid flow at the first temperature
by a third heat exchanger, and the third heat exchanger is
separated from the first heat exchanger by at least the second heat
exchanger. Moreover, the method includes applying, by one or more
components, one or more compressive forces to at least one or more
first thermoelectric materials, the second heat exchanger, and one
or more second thermoelectric materials. The one or more first
thermoelectric materials are sandwiched between the first heat
exchanger and the second heat exchanger, and the one or more second
thermoelectric materials are sandwiched between the second heat
exchanger and the third heat exchanger. The one or more first
thermoelectric materials, the second heat exchanger, and the one or
more second thermoelectric materials are located between the first
heat exchanger and the third heat exchanger. The process for
applying, by one or more components, one or more compressive forces
includes extending the one or more components from the first heat
exchanger to the third heat exchanger without making any thermal
contact with the second heat exchanger. For example, the method is
implemented according to at least FIG. 9.
[0207] In another example, the process for applying, by one or more
components, one or more compressive forces includes extending the
one or more components from the first heat exchanger to the third
heat exchanger without making any thermal contact with the one or
more first thermoelectric materials and without making any thermal
contact with the one or more second thermoelectric materials. In
yet another example, the one or more components include one or more
bolts.
[0208] Although specific embodiments of the present invention have
been described, it will be understood by those of skill in the art
that there are other embodiments that are equivalent to the
described embodiments. For example, various embodiments and/or
examples of the present invention can be combined. Accordingly, it
is to be understood that the invention is not to be limited by the
specific illustrated embodiments, but only by the scope of the
appended claims.
* * * * *