U.S. patent application number 14/669117 was filed with the patent office on 2015-08-06 for thermoelectric heat exchanger capable of providing two different discharge temperatures.
The applicant listed for this patent is DELPHI TECHNOLOGIES, INC.. Invention is credited to PRASAD S. KADLE, MINGYU WANG, EDWARD WOLFE, IV.
Application Number | 20150219367 14/669117 |
Document ID | / |
Family ID | 53754550 |
Filed Date | 2015-08-06 |
United States Patent
Application |
20150219367 |
Kind Code |
A1 |
KADLE; PRASAD S. ; et
al. |
August 6, 2015 |
THERMOELECTRIC HEAT EXCHANGER CAPABLE OF PROVIDING TWO DIFFERENT
DISCHARGE TEMPERATURES
Abstract
A thermoelectric heat exchanger and a thermoelectric heating,
ventilation and air conditioning system (HVAC) configured to
provide a cooled fluid or air stream and a heated fluid or air
stream. The thermoelectric heat exchanger may include a plurality
thermoelectric devices (TEDs), also known as thermoelectric coolers
(TECs) or Peltier coolers, in thermal communication. The
thermoelectric devices may be arranged in a three dimensional array
to provide compact packaging for the thermoelectric heat exchanger
assembly. The thermoelectric heat exchanger may be configured to
transfer thermal energy between a first thermoelectric device and a
second thermoelectric device via evaporation and condensation of a
working fluid or refrigerant contained within the thermoelectric
heat exchanger.
Inventors: |
KADLE; PRASAD S.;
(WILLIAMSVILLE, NY) ; WANG; MINGYU; (AMHERST,
NY) ; WOLFE, IV; EDWARD; (CLARENCE CENTER,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DELPHI TECHNOLOGIES, INC. |
TROY |
MI |
US |
|
|
Family ID: |
53754550 |
Appl. No.: |
14/669117 |
Filed: |
March 26, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13428560 |
Mar 23, 2012 |
|
|
|
14669117 |
|
|
|
|
Current U.S.
Class: |
62/3.2 |
Current CPC
Class: |
B60H 1/00478 20130101;
F25B 2321/02 20130101; F28D 15/0275 20130101; F28D 15/0266
20130101; B60H 1/00321 20130101; F28D 15/0233 20130101; H01L 35/30
20130101; F25B 21/02 20130101 |
International
Class: |
F25B 21/02 20060101
F25B021/02 |
Claims
1.-18. (canceled)
19. A cross flow heat exchanger assembly configured to heat a first
portion of a fluid flowing through said cross flow heat exchanger
assembly and cool a second portion of the fluid flowing through
said cross flow heat exchanger assembly, wherein the first portion
is segregated from the second portion, said cross flow heat
exchanger assembly comprising: a first thermoelectric device
configured to heat said first portion of the fluid; a second
thermoelectric device configured to cool said second portion of the
fluid; a first tube in thermal communication with the first
thermoelectric device; a second tube in thermal communication with
the second thermoelectric device; a first shell defining a first
cavity oriented to contain a working fluid in a substantially
liquid phase and sealably coupled to the first tube and the second
tube; and a second shell defining a second cavity oriented to
contain the working fluid in a substantially vapor phase, and
sealably coupled to the first tube and the second tube, wherein the
first cavity and the second cavity are in fluidic communication
through the first tube and the second tube, wherein the first
thermoelectric device is configured to condense the working fluid
within the first tube and the second thermoelectric device is
configured to vaporize the working fluid within the second tube,
thereby transferring thermal energy between the first
thermoelectric device and the second thermoelectric device through
evaporation and condensation of the working fluid.
20. The cross flow heat exchanger assembly according to claim 19,
further comprising a thermally insulative bulkhead intermediate the
first tube and the second tube configured to segregate the first
portion and the second portion of the fluid flowing through the
cross flow heat exchanger assembly.
21. The cross flow heat exchanger assembly according to claim 19,
further comprising: a first fin thermally coupled to the first
thermoelectric device and configured to cool said first portion of
the fluid; and a second fin thermally coupled to the second
thermoelectric device and configured to heat said second portion of
the fluid.
22. The cross flow heat exchanger assembly according to claim 21,
further comprising: a plurality of first thermoelectric devices
thermally coupled to a plurality of first tubes; and a plurality of
second thermoelectric devices thermally coupled to a plurality of
second tubes.
23. The cross flow heat exchanger assembly according to claim 22,
wherein the plurality of first thermoelectric devices are arranged
on an outer surface of each of the first tubes in the plurality of
first tubes in a two dimensional array and wherein the plurality of
second thermoelectric devices are arranged on another outer surface
of each of the second tubes in the plurality of second tubes in
another two dimensional array.
24. The cross flow heat exchanger assembly according to claim 22,
further comprising: a plurality of first fins thermally coupled to
the plurality of first thermoelectric devices; and a plurality of
second fins thermally coupled to the plurality of second
thermoelectric devices.
25. The cross flow heat exchanger assembly according to claim 19,
further comprising: a support structure configured to support and
locate the first shell and the second shell relative to one another
and configured to direct the first portion and the second portion
of the fluid through said cross flow heat exchanger assembly.
26. The cross flow heat exchanger assembly according to claim 19,
wherein the second tube contains a wicking material configured to
draw liquid working fluid from the first shell into the second
tube.
27. The cross flow heat exchanger assembly according to claim 19,
wherein the first thermoelectric device is bonded to the first tube
by a thermally conductive adhesive and the second thermoelectric
device is bonded to the second tube by the thermally conductive
adhesive.
28. The cross flow heat exchanger assembly according to claim 19,
wherein the working fluid circulates within the cross flow heat
exchanger assembly via thermo-syphon action.
29. The cross flow heat exchanger assembly according to claim 19,
wherein the fluid is air.
30. The cross flow heat exchanger assembly according to claim 19,
wherein the fluid is a liquid.
31. A heating, ventilation, and air conditioning (HVAC) system
configured to heat a first portion of an air stream flowing through
said HVAC system while cooling a second portion of the air stream
flowing through said HVAC system, wherein said first portion is
segregated from said second portion, said HVAC system comprising:
the cross flow heat exchanger assembly according to claim 1,
wherein the fluid is air; an air moving device configured to move
said air stream through said HVAC system; a first plenum configured
to segregate said air stream into said first portion; and a second
plenum configured to segregate said air stream into said second
portion.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application and claims
benefit under 35 U.S.C. .sctn.120 of U.S. patent application Ser.
No. 13/428,560, filed Mar. 23, 2012, which claims benefit under 35
U.S.C. .sctn.119(e) of U.S. Provisional Patent Application No.
61/478.660, filed Apr. 25, 2011, the entire disclosure of each of
which is hereby incorporated herein by reference.
TECHNICAL FIELD OF INVENTION
[0002] The present disclosure relates to a thermoelectric heat
exchanger; more specifically, to a thermoelectric heat exchanger
capable of providing a fluid discharge at two different
temperatures.
BACKGROUND OF INVENTION
[0003] Presently, the passenger compartment in a vehicle is
typically cooled or heated by an air flow processed by a heating
ventilation and air conditioning (HVAC) system. The HVAC system may
be designed to provide cooling or heating to one or more zones in
the passenger compartment to provide different temperature zones
within the passenger compartment in order to optimize passenger
comfort. A common example is to provide independent temperature
control to the driver and front seat passenger seating areas.
[0004] Thermoelectric devices (TEDs), also known as thermoelectric
coolers (TECs) or Peltier coolers, may be used in the HVAC system
to provide warmed and or cooled air, especially in vehicles that
may not provide an adequate supply of waste heat, such as electric
or hybrid electric vehicles. A TED is a semiconductor-based device
that upon application of an electric voltage becomes hot on one
side and cold on the other side. A typical TED has the dimensions
of approximately 40 millimeters (length) by 40 millimeters (width)
by 4 millimeters (thickness). TEDs are available from a number of
sources including Ferrotec (USA) Corporation of Santa Clara,
California and Laird Technologies of Earth City, Missouri. The
construction, design, and operation of TEDs are well known to those
skilled in the art.
[0005] Because of the ability to provide heating and/or cooling, a
TED may be used in a HVAC system to change the temperature of the
air flow from the HVAC system. This may be especially beneficial
for changing the temperature of a portion of the air flow that may
be used for spot cooling or spot heating of areas within a vehicle
passenger compartment.
[0006] A heat exchanger comprising thermoelectric devices in a HVAC
system may present packaging difficulties. The capacity for heating
or cooling provided by an individual TED is limited, therefore
multiple TEDs are typically required to provide adequate heating or
cooling. Because TEDs provide heating on one side and cooling on
the other side of the device, an obvious solution for providing
adequate capacity is by arranging TEDs in a two dimensional array.
The length or width of the two dimensional array required can
easily exceed the packaging space available in the HVAC system. An
alternative packaging scheme is presented in German
Offenlegungsschrift DE 10-2010-021-901-A1 by Walter et. al. Walter
describes a one dimensional array of TEDs with a pair of serpentine
ducts interwoven between the array of TEDs in such a manner that
one duct is only in contact with the hot side of each TED and
provides a warmed fluid stream and the other duct is only in
contact with the cold side of each TED and provides a cooled fluid
stream. The length of the one dimensional array required to produce
adequate heating and cooling may also exceed the available
packaging space in the HVAC system. In addition, the fabrication
and assembly of the serpentine ducts would add undesirable
complexity and cost to the heat exchanger.
SUMMARY OF THE INVENTION
[0007] In accordance with one embodiment of this invention, a cross
flow heat exchanger assembly is provided. The cross flow heat
exchanger assembly is configured to heat a first portion of a fluid
flowing through the assembly and cool a second portion of the fluid
flowing through the assembly. The first portion of the fluid
flowing through the assembly is segregated from the second portion
of the fluid flowing through the assembly. The assembly includes a
first thermoelectric device (TED) that is configured to heat the
first portion of the fluid flowing through the assembly, a second
TED that is configured to cool the second portion of the fluid
flowing through the assembly, and a heat pipe that is configured to
transfer thermal energy between the first TED and the second TED
via evaporation and condensation of a working fluid contained
within the heat pipe.
[0008] In another embodiment of the present invention, a cross-flow
heat exchanger assembly is provided. The cross-flow heat exchanger
assembly is configured to heat a first portion of a fluid flowing
through the assembly and cool a second portion of the fluid flowing
through the assembly. The first portion of the fluid flowing
through the assembly is segregated from the second portion of the
fluid flowing through the assembly. The assembly includes a first
TED configured to heat the first portion of the fluid flowing
through the assembly and a second TED configured to cool the second
portion of the fluid flowing through the assembly. The assembly
further includes a first tube in thermal communication with the
first TED and configured to contain a working fluid. The assembly
additionally includes a second tube in thermal communication with
the second TED and configured to contain the working fluid. The
assembly also includes a first shell defining a first cavity that
is oriented to contain the working fluid in a substantially liquid
phase and a second shell defining a second cavity that is oriented
to contain the working fluid in a substantially vapor phase. The
first tube and the second tube are sealably coupled to the first
shell and the second shell. The first cavity and the second cavity
are in fluidic communication through the first tube and the second
tube. The assembly is configured to transfer thermal energy between
the first TED and the second TED through evaporation and
condensation of the working fluid. The second tube may further
contain a wicking material configured to transfer the working fluid
contained in the first cavity to the first tube. The working fluid
may circulate within the assembly via thermo-syphon action.
[0009] In yet another embodiment of the present invention, a
heating, ventilation, and air conditioning (HVAC) system is
provided. The heating, ventilation, and air conditioning system is
configured to cool a first portion of an air stream flowing through
the system and heat a second portion of the air stream flowing
through the system. The first portion of the air stream flowing
through the system is segregated from the second portion of the air
stream flowing through the system. The system includes a heat
exchanger assembly configured to change the temperature of the air
stream flowing through the system. The system additionally includes
a first plenum configured to segregate the air stream flowing
through the system into the first portion of the air stream flowing
through the system and a second plenum configured to segregate the
air stream flowing through the system into the second portion of
the air stream flowing through the system. The system further
includes a first TED configured to heat the first portion of the
air stream flowing through the system and cool the second portion
of the air stream flowing through the system.
[0010] The HVAC system may additionally include a first fin
disposed within the first plenum, a second fin disposed within the
second plenum, and a second TED thermally coupled to the second fin
and configured to cool the second portion of the air stream flowing
through the system. The first TED may be thermally coupled to the
first fin and may be configured to only heat the first portion of
the air stream flowing through the system. The first TED may be
thermally coupled to the second TED.
[0011] The HVAC system may further include a first plurality of
fins disposed within the first plenum, a second plurality of fins
disposed within the second plenum, a first plurality of TEDs
coupled to the first plurality of fins and configured to heat the
first portion, and a second plurality of TEDs coupled to the second
plurality of fins and configured to cool the second portion. The
first plurality of TEDs may be thermally coupled to the second
plurality of TEDs.
[0012] The HVAC system may further include a heat pipe configured
to transfer thermal energy between the first TED and the second TED
via evaporation and condensation of a working fluid contained
within the heat pipe.
[0013] The HVAC system may further include a first tube in thermal
communication with the first TED and configured to contain a
working fluid, a second tube in thermal communication with the
second TED and configured to contain the working fluid, a first
shell defining a first cavity configured to contain the working
fluid substantially in a liquid phase, and a second shell defining
a second cavity configured to contain the working fluid
substantially in a vapor phase. The first tube and the second tube
may be sealably coupled to the first shell and the second shell.
The first cavity and the second cavity may be in fluidic
communication through the first tube and the second tube. The
system may be configured to transfer thermal energy between the
first TED and the second TED through evaporation and condensation
of the working fluid.
[0014] Further features and advantages of the invention will appear
more clearly on a reading of the following detailed description of
the preferred embodiment of the invention, which is given by way of
non-limiting example only and with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0015] The present invention will now be described, by way of
example with reference to the accompanying drawings, in which:
[0016] FIG. 1 is a cutaway side view diagram of a vehicle equipped
with an HVAC system including a thermoelectric heat exchanger in
accordance with one embodiment;
[0017] FIG. 2 is a cutaway side view diagram of a stacked
thermoelectric heat exchanger including a sealed thermoelectric
heat exchanger as shown in FIG. 3 with a heating section and a
cooling section in accordance with another embodiment;
[0018] FIG. 3 is a cutaway side view diagram of a sealed
thermoelectric heat exchanger including a heat pipe charged with
working fluid in accordance with one embodiment;
[0019] FIG. 3A is a cutaway top view diagram of the heat pipe
assembly of FIG. 3 in accordance with one embodiment;
[0020] FIG. 4 is a cutaway side view diagram of a thermoelectric
heat exchanger charged with a working fluid in accordance with
another embodiment;
[0021] FIG. 5 is a cutaway side view diagram of a heating,
ventilation, and air conditioning HVAC system including a
thermoelectric heat exchanger in accordance with another
embodiment;
[0022] FIG. 6 is a cutaway side view diagram of a HVAC system
including a sealed thermoelectric heat exchanger as shown in FIG. 3
in accordance with another embodiment;
[0023] FIG. 7 is a cutaway side view diagram of a HVAC system
including a stacked thermoelectric heat exchanger as shown in FIG.
2 in accordance with another embodiment; and
[0024] FIG. 8 is a cutaway top view diagram of a HVAC system
including a thermoelectric heat exchanger as shown in FIG. 4 in
accordance with another embodiment.
DETAILED DESCRIPTION OF INVENTION
[0025] Because thermoelectric devices (TEDs) provide heating on one
side and cooling on the other side of the device, an obvious
solution for providing adequate cooling and heating capacity is to
arrange TEDs in a two dimensional array. The length or width of the
two dimensional array required can easily exceed the packaging
space available in a heating, ventilation, and air conditioning
(HVAC) system. An alternative one dimensional array of TEDs is
presented in German Offenlegungsschrift DE 10-2010-021-901-A1 which
describes a pair of serpentine ducts interwoven between the array
of TEDs in such a manner that one duct is only in contact with the
hot side of each TED and provides a warmed fluid stream and the
other duct is only in contact with the cold side of each TED and
provides a cooled fluid stream. The length of the one dimensional
array may also exceed the available packaging space in the HVAC
system.
[0026] Instead of packaging TEDs in a heat exchanger in a one
dimensional array as is shown in the prior art or an obvious two
dimensional array, the TEDs may be arranged in a three dimensional
array. Arranging the TEDs in a three dimensional array may provide
a heat exchanger assembly that is more compact and thus easier to
package within the confines of a HVAC system. The TEDs may be
configured to cool a first portion of a fluid (as a non-limiting
example, air) flowing through a cooling region of the assembly that
is, for example directed toward one part of a person's body, and
heat a second portion of the fluid flowing through a heating region
of the assembly that is, for example directed toward another part
of a person's body. The TEDs are preferably arranged so that one
section of the heat exchanger cools the first portion of a fluid
flowing through the assembly and another section of the heat
exchanger heats the second portion of a fluid flowing through the
assembly. The thermoelectric heat exchanger must be configured so
that the thermal energy absorbed by the TEDs that are cooling the
first portion of the fluid is transferred to the TEDs that are
heating the second portion of the fluid.
[0027] FIG. 1 illustrates a non-limiting example of heating,
ventilation, and air conditioning (HVAC) system 10 that may be
configured for use in a vehicle 12 to provide a first portion 14 of
an air stream 16 for spot heating and a second portion 18 of the
air stream 16 for spot cooling of a passenger 20 within the
passenger compartment 22 of the vehicle 12. It is recognized that
this independent heating and cooling could also be used to
separately control the temperatures of the passenger 20 and an
operator (not shown) of the vehicle 12.
[0028] The HVAC system 10 may include a conventional heat exchanger
24 (e.g. heater core or evaporator) in addition to a thermoelectric
heat exchanger 26. The conventional heat exchanger 24 may be
configured to provide a base output temperature and the
thermoelectric heat exchanger 26 may be configured to increase and
decrease the base output temperature to provide independent spot
heating and spot cooling of separate parts of the body of the
passenger 20. The thermoelectric heat exchanger 26 may be capable
of providing air at two different discharge temperatures.
[0029] FIG. 2 illustrates a non-limiting example of an embodiment
of a cross flow thermoelectric heat exchanger assembly 100
configured to heat a first portion 112 of a fluid flowing through a
heating region 113 of the assembly 100 (the upper portion as shown
in FIG. 2) and cool a second portion 114 of the fluid flowing
through the a cooling region 115 assembly 100 (the lower portion as
shown in FIG. 2). The assembly 100 includes of a plurality of
thermoelectric assemblies 110 as shown in detail in FIG. 3 that
include a plurality of first TEDs 116 and a plurality of second
TEDs 118.
[0030] FIG. 3 illustrates a non-limiting example of the
thermoelectric assembly 110. The thermoelectric assembly 110
includes the first thermoelectric device (TED) 116 that is
configured to heat the first portion 112 of the fluid flowing
through the assembly 100. The heat exchanger also includes the
second TED 118 that is configured to cool the second portion 114 of
the fluid flowing through the assembly 100.
[0031] The thermoelectric assembly 110 further includes a heat pipe
133 that is configured to transfer thermal energy between the first
TED 116 and the second TED 118 via (i.e. using the mechanism of)
evaporation and condensation of a working fluid 134 contained
within a cavity 136 defined by the heat pipe 133.
[0032] The heat pipe 133 in this non-limiting example is a sealed
pipe or tube. The heat pipe 133 may define an upper section 142 and
a lower section 144. The heat pipe 133, as a non-limiting example,
may have a rectangular cross section wherein the width 138 of the
heat pipe 133 is preferably greater than the width 139 of the first
TED 116 and the second TED 118. The thickness of the heat pipe 133
is preferably greater than 1.6 mm. The first TED 116 may be
preferably located proximate to and thermally coupled to the upper
section 142 of the heat pipe 133. The second TED 118 may be
preferably located proximate to and thermally coupled to the lower
section 144 of the heat pipe 133. The first TED 116 and the second
TED 118 may be bonded to the heat pipe 133 by a thermally
conductive adhesive, such as aluminum filled epoxy adhesive TC-2707
available from the 3M Company of Saint Paul, Minn.
[0033] The heat pipe 133 is preferably constructed of a material
having a high thermal conductivity, such as copper or aluminum
alloy for both the upper section 142 and the lower section 144. The
heat pipe 133 forms a cavity 136 that is typically sealed at the
top and bottom after it is charged with the working fluid 134. A
vacuum pump is typically used to remove a large portion of air from
the cavity 136, and then the cavity 136 is filled with a fraction
of a percent by volume of working fluid 134 chosen to match the
operating temperature of the assembly 100. Examples of suitable
working fluids may include ethanol, acetone,
1,1,1,2-Tetrafluoroethane (refrigerant R134a), or
2,3,3,3-Tetrafluoropropene (refrigerant HFO-1234yf).
[0034] The heat pipe 133 employs evaporative cooling to transfer
thermal energy from the lower portion to the upper portion by the
evaporation and condensation of the working fluid 134. The heat
pipe 133 relies on a temperature difference between the upper
section 142 and the lower section 144 of the heat pipe 133 created
by the operation of the first TED 116 and the second TED 118.
[0035] Without prescribing to any particular theory of operation,
when the lower section 144 of the heat pipe 133 is heated by the
thermal energy transferred from the second portion 114 of the fluid
flowing through the assembly 100 by the second TED 118, the working
fluid 134 inside the cavity 136 evaporates. The warmed vapor then
rises to the upper section 142 and warms the upper section 142 of
the heat pipe 133. The first TED 116 then transfers thermal energy
from the vapor to the first portion 112 of the fluid flowing
through the assembly 100. The first TED 116 also cools the upper
section 142 of the heat pipe 133, thereby condensing the vapor back
into a liquid working fluid 134.
[0036] Although a heat exchanger assembly could be constructed in a
similar fashion to assembly 100 using a solid thermal conducting
element, such as a copper plate, thermal energy transfer capability
of the solid thermal conducting element is inferior to the heat
pipe 133 of assembly 100.
[0037] The condensed working fluid 134 then flows back to the lower
section 144 of the heat pipe 133. In the case of a
vertically-oriented heat pipe 133, the condensed working fluid 134
may be moved from the upper section 142 to the lower section 144 by
the force of gravity. In the case of horizontally oriented heat
pipes, the cavity 136 of the heat pipe 133 may contain a wicking
material 148 configured to transfer condensed vapor contained in a
first segment 143 of the heat pipe 133 to a second segment 145 of
the heat pipe 133 by capillary action. The construction, design,
and utilization of heat pipes are well known to those skilled in
the art.
[0038] The thermoelectric assembly 110 may preferably include a
plurality of first TEDs 116 that are configured to heat the first
portion 112 of the fluid flowing through the thermoelectric
assembly 110 and a plurality of second TEDs 118 configured to cool
the second portion 114 of the fluid flowing through the
thermoelectric assembly 110. The plurality of first TEDs 116 and
the plurality of second TEDs 118 may be arranged in a three
dimensional array as shown in FIG. 3.
[0039] Referring once more to FIG. 2, the heat exchanger assembly
100 may include a plurality of first fins 120 are disposed between
and thermally coupled to the plurality of first TEDs 116 and
configured to be disposed within the first portion 112 of the fluid
flowing through the assembly 100. The assembly 100 may also include
a plurality of second fins 122 is disposed between and thermally
coupled to the plurality of second TEDs 118 and configured to be
disposed within the second portion 114 of the fluid flowing through
the assembly 100. The plurality of first fins 120 and the plurality
of second fins 122 are preferably constructed of a material having
a high thermal conductivity, such as copper or aluminum alloys. The
plurality of first fins 120 and plurality of second fins 122 may be
serpentine fins or any other thermally conductive fin type commonly
known in the art. The plurality of first fins 120 and the plurality
of second fins 122 may be bonded to the thermal plates of the first
TEDs 116 and the second TEDs 118 using a suitable adhesive, such as
a thermally conductive epoxy resin adhesive such as such as an
aluminum filled epoxy adhesive.
[0040] The plurality of first fins 120 and the plurality of second
fins 122 provide the advantage improving thermal energy transfer
between the plurality of first TEDs 116 and the first portion 112
of the fluid flowing through the assembly 100 and the plurality of
second TEDs 118 and the second portion 114 of the fluid flowing
through the assembly 100 by increasing the surface area exposed to
the fluid flowing through the assembly 100.
[0041] The assembly 100 may further include a support structure 126
to support and locate the thermoelectric assemblies 110 within the
assembly 100. The assembly 100 may additionally include a bulkhead
128 disposed between the plurality of first fins 120 and the
plurality of second fins 122 that is configured to segregate the
fluid flowing through the thermoelectric assembly 110 into the
first portion 112 and the second portion 114. The bulkhead 128 is
preferably constructed of a thermally non-conductive material, such
as polypropylene to minimize the transfer of thermal energy from
the first portion 112 of the fluid flowing through the
thermoelectric assembly 110 to the second portion 114 of the fluid
flowing through the thermoelectric assembly 110. Additionally, the
bulkhead 128 may be configured to thermally isolate the first fin
120 from the second fin 122. The assembly 100 may alternatively
contain a single thermoelectric assembly 110. The assembly 100 may
alternatively contain a single first TED 116 and a single second
TED 118. The assembly 100 may alternatively not include a plurality
of first fins 120 or a plurality of second fins 122.
[0042] The assembly 100 may further include a first power supply
130 electrically coupled to the plurality of first TEDs 116 and a
second power supply 132 electrically coupled to the plurality of
second TEDs 118. A first voltage supplied by the first power supply
130 is different from and preferably of opposite polarity of a
second voltage supplied by the second power supply 132. The first
voltage and the second voltage may have the same voltage value but
opposite polarity. The first power supply 130 and second power
supply 132 is preferably configured to provide a direct current
(DC) first voltage and second voltage. Alternatively, a single
power supply may be coupled to both the plurality of first TEDs 116
and the plurality of second TEDs 118, wherein the first voltage
applied to the first TED 116 is the same voltage value but opposite
polarity of the second voltage applied to the second TED 118.
Alternatively, a single power supply may be electrically coupled to
the plurality of first TEDs 116 by a first pulse-width modulated
(PWM) controller and may be electrically coupled the plurality of
second TEDs 118 by a second PWM controller. The duty cycle of the
first PWM controller may differ from the duty cycle of the second
PWM controller in order to provide different effective voltages to
the plurality of first TEDs 116 and the plurality of second TEDs
118.
[0043] Preferably the same first voltage is supplied to each of the
plurality of first TEDs 116 and the same second voltage (albeit
different from the first voltage) is supplied to each of the
plurality of second TEDs 118. The assembly 100 may provide the
advantage of producing two streams of air having different
temperatures, wherein each stream of air has a generally uniform
temperature distribution. Multiple heat exchanger assemblies 100
may be combined to provide multiple portions of cooled fluid and
heated fluid, each at a different temperature by applying different
voltages to the TEDs.
[0044] FIG. 4 illustrates another non-limiting example of an
embodiment of a cross flow thermoelectric heat exchanger assembly
200 that is configured to heat a first portion 212 of a fluid
flowing through a heating region 215 of the assembly 200 (the right
side as shown in FIG. 4) and cool a second portion 214 of the fluid
flowing through a cooling region 213 of the assembly 200 (the left
side as shown in FIG. 4). The fluid flowing through the assembly
200 may be a liquid or a gas, such as air. The first portion 212 of
the fluid flowing through the assembly 200 is segregated from the
second portion 214 of the fluid flowing through the assembly 200.
The heat exchanger assembly 200 includes a first TED 216 that is
configured to heat the first portion 212 of the fluid flowing
through the assembly 200. The heat exchanger also includes a second
TED 218 configured to cool the second portion 214 of the fluid
flowing through the assembly 200.
[0045] Alternatively, the first TED 216 may be configured to cool
the first portion 212 of the fluid flowing through the assembly 200
and the second TED 218 may be configured to heat the second portion
214 of the fluid flowing through the assembly 200 by changing an
electrical voltage applied to the first TED 216 and the second TED
218.
[0046] The assembly 200 further includes a first tube 248 that is
in thermal communication with the first TED 216 and is configured
to contain a working fluid 234 such as refrigerant R134a, or
HFO-1234yf. The assembly 200 also includes a second tube 250 that
is in thermal communication with the second TED 218 and is
configured to contain the working fluid 234. The assembly 200
further includes a first shell 252 that defines a first cavity 254
oriented to contain the working fluid 234 in a substantially liquid
phase. As used herein, the substantially liquid phase contains no
more than 10 percent vapor. The assembly 200 additionally includes
a second shell 256 that defines a second cavity 258 that is
oriented to contain the working fluid 234 in a substantially vapor
phase. As used herein, the substantially vapor phase contains no
more than 10 percent liquid. The first tube 248 and the second tube
250 are sealably coupled to the first shell 252 and the second
shell 256. The first cavity 254 and the second cavity 258 are in
fluidic communication through the first tube 248 and the second
tube 250. The assembly 200 is configured to transfer thermal energy
between the first TED 216 and the second TED 218 through
evaporation of the working fluid 234 in the second tube 250 and
condensation of the working fluid 234 in the first tube 248.
[0047] The first shell 252, the second shell 256, the first tube
248 and the second tube 250 are preferably constructed of a
material having a high thermal conductivity, such as copper or
aluminum alloys. The first TED 216 and the second TED 218 may be
bonded to the first tube 248 and the second tube 250 respectively
using a thermally conductive adhesive, such as aluminum filled
epoxy. The first tubes 248 and the second tubes 250 may be bonded
to the first shell 252 and second shell 256 by braising or adhesive
such as epoxy or methyl acrylate. Use of adhesives is preferable if
the first TED 216 and the second TED 218 are bonded to the first
tube 248 and the second tube 250 prior to assembling the first
tubes 248 and the second tubes 250 to the first shell 252 and the
second shell 256 due to concerns of damaging the first TED 216 or
the second TED 218 due to the heat of braising. The assembly 200
may also include a support structure 226 to support and locate the
first shell 252 and the second shell 256 within the assembly 200.
The support structure 226 may also be configured to direct the
first portion 212 and the second portion 214 of the fluid lowing
through the assembly 200. The heat exchanger assembly 200 may be
constructed using methods and designs for tube and shell heat
exchangers that are well known to those skilled in the art.
[0048] The ends of the first tube 248 and the second tube 250 are
not sealed, but are fluidicly coupled to the first cavity 254 of
the first shell 252 and the second cavity 258 of the second shell
256. The ends of the first tube 248 and second tube 250 are
disposed in the first cavity 254 of the first shell 252 and the
second cavity 258 of the second shell 256 at both ends of the heat
exchanger. The assembly 200 may be divided horizontally into two
sections by a thermally insulating bulkhead 228.
[0049] The end of the first tube 248 that is disposed in the first
cavity 254 may be submerged in the working fluid 234 which is in a
substantially liquid state. The second tube 250 may contain a
wicking material 246. Without prescribing to any particular theory
of operation, as the liquid working fluid 234 is wicked into the
second tube 250, the second TED 218 transfers heat energy from the
second portion 214 of the fluid flowing through the assembly 200 to
the working fluid 234. In the process, the liquid working fluid 234
is boiled thus forming a vapor. Convection causes the vapor to flow
through the second tube 250 to the end of the second tube 250 that
is disposed in the second cavity 258, thereby discharging the vapor
into the second cavity 258.
[0050] The wicking material 246 provides the advantage of drawing
liquid working fluid 234 into the second tube 250 which increases
the amount of working fluid 234 in the second tube 250 that is
available to absorb thermal energy from the second TED 218. Without
the wicking material 246, the liquid working fluid 234 may contact
the second tube 250 only where the end of the second tube 250
extends into the first cavity 254 of the first shell 252, providing
very little surface area for the liquid working fluid 234 to
contact the second tube 250.
[0051] The vapor in the second cavity 258 contacts the end of the
first tube 248 that is disposed in the second cavity 258. Because
the first TED 216 is transferring heat energy from the working
fluid 234 to the first portion 212 of the fluid flowing through the
assembly 200, the first TED 216 cools the first tube 248. As vapor
flows into the first tube 248 and is exposed to the cold sides of
the first tube 248, it condenses into liquid working fluid 234. The
liquid working fluid 234 may flow through the first tube 248 to the
end of the first tube 248 that is disposed in the first cavity 254
and into the first cavity 254 under the influence of gravity, thus
completing a cycle for the working fluid 234. The working fluid 234
may circulate within the assembly 200 via convection or
thermo-syphon action. Alternatively, the first tube 248 may also
contain wicking material to return condensed working fluid 234 to
the first cavity 254 via capillary action.
[0052] As shown in FIG. 4, the assembly 200 may further include a
first thermally conductive fin 220 that is thermally coupled to the
first TED 216 and is disposed within the first portion 212 of the
fluid flowing through the assembly 200. The assembly 200 may also
include a second thermally conductive fin 222 that is thermally
coupled to the second TED 218 and disposed within the second
portion 214 of the fluid flowing through the assembly 200. The
first fin 220 and the second fin 222 are preferably constructed of
a material having a high thermal conductivity, such as copper or
aluminum alloys. The first fin 220 and second fin 222 may be
serpentine fins or any other thermally conductive fin type commonly
known in the art. The first fin 220 and the second fin 222 may be
bonded to the thermal plates of the first TED 216 and the second
TED 218 respectively using a suitable adhesive, such as a thermally
conductive epoxy resin adhesive such as such as an aluminum filled
epoxy adhesive.
[0053] The first fins 220 and the second fins 222 provide the
advantage improving thermal energy transfer between the first TED
216 and the first portion 212 of the fluid flowing through the
assembly 200 and the second TED 218 and the second portion 214 of
the fluid flowing through the assembly 200 by increasing the
surface area exposed to the fluid flowing through the assembly
200.
[0054] The bulkhead 228 may be disposed between the first fin 220
and the second fin 222 to segregate the fluid flowing through the
assembly 200 into the first portion 212 and the second portion 214.
The bulkhead 228 is preferably constructed of a thermally
non-conductive material, such as polypropylene to minimize the
transfer of thermal energy from the first portion 212 of the fluid
flowing through the assembly 200 to the second portion 214 of the
fluid flowing through the assembly 200. Additionally, the bulkhead
228 may be configured to thermally isolate the first fin 220 from
the second fin 222.
[0055] The assembly 200 may further include a first power supply
230 electrically coupled to the first TED 216 and a second power
supply 232 electrically coupled to the second TED 218. A first
voltage supplied by the first power supply 230 is different from
and preferably of opposite polarity of a second voltage supplied by
the second power supply 232. The first voltage and the second
voltage may have the same voltage value but opposite polarity. The
first power supply 230 and the second power supply 232 are
preferably configured to provide a direct current (DC) first
voltage and second voltage. Alternatively, a single power supply
may be coupled to both the first TED 216 and the second TED 218,
wherein the first voltage applied to the first TED 216 is the same
voltage value but opposite polarity of the second voltage applied
to the second TED 218.
[0056] The assembly 200 may additionally include a plurality of
first TEDs 216 that are configured to heat the first portion 212 of
the fluid flowing through the assembly 200 and a plurality of
second TEDs 218 that are configured to cool the second portion 214
of the fluid flowing through the assembly 200. The assembly 200 may
further includes a plurality of first tubes 248 that is in thermal
communication with the plurality of first TEDs 216 and a plurality
of second tubes 250 that is in thermal communication with the
plurality of second TEDs 218. The assembly 200 may further include
a plurality of first fins 220 that are thermally coupled to the
plurality of first TEDs 216 and are disposed within the first
portion 212 of the fluid flowing through the assembly 200 and a
plurality of second fins 222 that are thermally coupled to the
plurality of second TEDs 218 and disposed within the second portion
214 of the fluid flowing through the assembly 200. The plurality of
first TEDs 216 may be arranged on each outer surface of the
plurality of first tubes 248 in a two dimensional array. Likewise,
the plurality of second TEDs 218 may be arranged on each outer
surface of the plurality of second tubes 250 in a two dimensional
array.
[0057] The plurality of first TEDs 216 may be connected to a common
first power supply 230 having a first voltage. Each TED in the
plurality of first TEDs 216 has the same electrical polarity. The
plurality of first TEDs 216 may be arranged proximate to the first
tube 248 in such a manner so as to provide cooling to the working
fluid 234 inside the first tube 248.
[0058] Similarly, the plurality of second TEDs 218 may be connected
to a common second power supply 232 having a second voltage. Each
TED and in the plurality of second TEDs 218 has the same electrical
polarity and the second voltage is the opposite polarity of the
first voltage. The plurality of second TEDs 218 may be arranged
proximate to the second tube 250 in such a manner so as to provide
heating to the working fluid 234 inside the second tube 250. The
assembly 200 may provide the advantage of producing two streams of
air having different temperatures, each streams of air having a
generally uniform temperature distribution. Multiple heat exchanger
assemblies 200 may be combined to provide multiple portions of
cooled fluid and heated fluid, each at a different temperature.
[0059] FIG. 5 illustrates a non-limiting example of another
embodiment of a thermoelectric heating, ventilation, and air
conditioning (HVAC) system 300 configured to cool a first portion
312 of an air stream 305 flowing through the system 300 and heat a
second portion 314 of the air stream 305 flowing through the system
300. The first portion 312 of the air stream 305 flowing through
the system 300 is segregated from the second portion 314 of the air
stream 305 flowing through the system 300.
[0060] The system 300 includes a heat exchanger assembly 358
configured to change the temperature of the air stream 305 flowing
through the system 300. The heat exchanger may be configured to
heat the air stream 305 flowing through the system 300, such as a
heater core used in internal combustion engine powered vehicle that
provides waste heat from the engine's coolant. Alternatively, the
heat exchanger may be configured to cool the air stream 305 flowing
through the system 300, such as an evaporator used in a
refrigeration system or an air conditioning system. The system 300
may include two heat different exchangers, one configured to heat
the air stream 305 and one configured to cool the air stream 305
flowing through the system 300. The system 300 may preferably
include a housing 360 to contain the airflow through the system
300. The system 300 may also preferably include a fan 362 or other
air moving device to force the air flow through the system 300.
[0061] The system 300 also includes a first plenum 364 configured
to segregate the air stream 305 flowing through the system 300 into
the first portion 312 of the air stream 305 flowing through the
system 300 and a second plenum 366 configured to segregate the air
stream 305 flowing through the system 300 into the second portion
314 of the air stream 305 flowing through the system 300.
[0062] The system 300 further includes a first TED 316 configured
to heat the first portion 312 of the air stream 305 flowing through
the system 300 and cool the second portion 314 of the air stream
305 flowing through the system 300. The first TED 316 may be
disposed intermediate to the first plenum 364 and the second plenum
366. The design and construction methods of HVAC system housings,
air movement devices, heater cores, evaporators, and plenums are
well known to those skilled in the art.
[0063] FIG. 6 illustrates a non-limiting example of another
embodiment the system 300 wherein the system 300 may include a
first fin 434 disposed within the first plenum 364 and a second fin
436 disposed within the second plenum 366. The system 300 may
further include a second TED 416 that is thermally coupled to the
second fin 436 and configured to cool the second portion 314 of the
air stream 305 flowing through the system 300. The first TED 316
may be coupled to the first fin 434 and may be configured to only
heat. The first TED 316 may be thermally coupled to the second TED
416.
[0064] FIG. 7 illustrates a non-limiting example of another
embodiment of the system 300 wherein the system 300 includes the
assembly 100 as shown in FIG. 2. The first plenum 364 is configured
to direct the first portion 312 of the air stream 305 flowing
through the system 300 through the upper portion of the assembly
100. The second plenum 366 is configured to direct the second
portion 314 of the air stream 305 flowing through the system 300
through the lower portion of the assembly 100.
[0065] FIG. 8 illustrates a non-limiting example of another
embodiment of the system 300 wherein the system 300 includes the
assembly 200 as shown in FIG. 4. The first plenum 364 is configured
to direct the first portion 312 of the air stream 305 flowing
through the system 300 through the right side of the assembly 200.
The second plenum 366 is configured to direct the second portion
314 of the air stream 305 flowing through the system 300 through
the left side of the assembly 200.
[0066] Accordingly, a heat exchanger assembly 100, 200 and a
heating, ventilation, and air conditioning (HVAC) system 300 is
provided. The heat exchanger assembly 100, 200 may be configured to
provide both heating and cooling of a fluid stream, such as air,
flowing through the assembly 100, 200. The assembly 100, 200 may
provide a compact thermoelectric heat exchanger that may be easier
to package, for example in a HVAC system, due to arrangement of the
thermoelectric devices 116, 118, 216, 218 in a three dimensional
array within the heat exchanger assembly 100, 200. The inclusion of
a working fluid 134, 234 within the assembly 100, 200 enhances the
transfer of thermal energy between the first TED 116, 216 and the
second TED 118, 218. The heat exchanger assembly 100, 200 may be
used in electric or hybrid electric vehicles where conventional
sources of heating and cooling are not readily available. In
addition, the assembly 200 may be constructed using many of the
design elements and methods of a conventional heat exchanger
assembly.
[0067] The HVAC system 300 may utilize a thermoelectric heat
exchanger assembly to provide streams of heated and cooled air for
spot cooling and spot heating of a passenger 20 in a passenger
compartment 22 of a vehicle 12. Several spot cooling and spot
heating air streams may be needed to meet passenger comfort
requirements. Different part of the body of the passenger 20 also
requires different air temperatures. A HVAC system 300 of the
design shown in FIGS. 5 through 8 should meet the discharge
temperature requirement for spot cooling and heating.
[0068] While this invention has been described in terms of the
preferred embodiments thereof, it is not intended to be so limited,
but rather only to the extent set forth in the claims that follow.
Moreover, the use of the terms first, second, etc. does not denote
any order of importance, but rather the terms first, second, etc.
are used to distinguish one element from another. Furthermore, the
use of the terms a, an, etc. do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced items.
* * * * *