U.S. patent application number 11/018341 was filed with the patent office on 2005-05-12 for integrated heat management of electronics and fuel cell power system.
Invention is credited to Acker, William P..
Application Number | 20050100769 11/018341 |
Document ID | / |
Family ID | 31494581 |
Filed Date | 2005-05-12 |
United States Patent
Application |
20050100769 |
Kind Code |
A1 |
Acker, William P. |
May 12, 2005 |
Integrated heat management of electronics and fuel cell power
system
Abstract
A method and apparatus for managing heat generated by a device
that is powered at least in part by a direct oxidation fuel cell.
Additional heat tends to improve the reaction in the direct
oxidation fuel cell, such that heat produced by a powered device
can be harnessed to increase the temperature of the reaction in the
direct oxidation fuel cell. By doing so, the performance of the
fuel cell can be enhanced and the temperature of the
heat-generating portion of the device maintained.
Inventors: |
Acker, William P.; (Rexford,
NY) |
Correspondence
Address: |
CESARI AND MCKENNA, LLP
88 BLACK FALCON AVENUE
BOSTON
MA
02210
US
|
Family ID: |
31494581 |
Appl. No.: |
11/018341 |
Filed: |
December 21, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11018341 |
Dec 21, 2004 |
|
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|
10213987 |
Aug 7, 2002 |
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Current U.S.
Class: |
429/436 ;
429/442; 429/444; 429/505 |
Current CPC
Class: |
Y02B 90/10 20130101;
H01M 8/04007 20130101; H01M 8/04201 20130101; H01M 2250/30
20130101; H01M 8/04029 20130101; Y02E 60/523 20130101; Y02E 60/50
20130101; H01M 8/04014 20130101; H01M 8/04186 20130101; H01M
8/04089 20130101; Y02B 90/18 20130101; H01M 8/1011 20130101 |
Class at
Publication: |
429/024 ;
429/026; 429/013 |
International
Class: |
H01M 008/04 |
Claims
What is claimed is:
1. An apparatus for managing heat generated by a device that is
powered at least in part by a direct oxidation fuel cell,
comprising: a direct oxidation fuel cell coupled to provide power
to said device; an oxygen source; and a conduit coupling said
oxygen source to said fuel cell and arranged so as to transfer at
least some heat produced by a heat generating portion of said
device to the oxygen flowing in the conduit, whereby an operating
temperature of said device is regulated and an operating
temperature of said fuel cell is raised.
2. The apparatus as defined in claim 1 wherein heat is transferred
to the oxygen flowing in the conduit prior to introduction to the
fuel cell.
3. The apparatus as defined in claim 1 wherein heat is transferred
to the oxygen flowing in the conduit following introduction to the
fuel cell.
4. The apparatus as defined in claim 1 wherein said heat transfer
is substantially conductive.
5. The apparatus as defined in claim 1 wherein said heat transfer
is substantially convective.
6. The apparatus as defined in claim 1 wherein said conduit is
arranged to transport said heated oxygen to a cathode face of said
fuel cell.
7. The apparatus as defined in claim 1 wherein said conduit is
arranged to increase the transfer of heat to the oxygen.
8. The apparatus as defined in claim 1 wherein said conduit is
arranged in a serpentine pattern.
9. The apparatus as defined in claim 1 further comprising a fan for
driving oxygen through said conduit.
10. A method for managing heat generated by a device that is
powered at least in part by a direct oxidation fuel cell system,
comprising: providing a device that is powered at least in part by
a direct oxidation fuel cell system, said fuel cell system
including a conduit coupling an oxygen source to said system;
transferring at least a portion of the heat generated by said
device to the oxygen flowing in said conduit, whereby an operating
temperature of said device is regulated and an operating
temperature of said fuel cell is raised.
11. The method as defined in claim 10 wherein heat is transferred
to the oxygen flowing in the conduit prior to introduction to the
fuel cell.
12. The method as defined in claim 10 wherein heat is transferred
to the oxygen flowing in the conduit following introduction to the
fuel cell.
13. The method as defined in claim 10 wherein said heat transfer is
substantially conductive.
14. The method as defined in claim 10 wherein said heat transfer is
substantially convective.
15. The method as defined in claim 10 wherein said conduit is
arranged to transport said heated oxygen to a cathode face of said
fuel cell.
16. The method as defined in claim 10 wherein said conduit is
arranged to increase the transfer of heat to the oxygen.
17. The method as defined in claim 10 wherein said conduit is
arranged in a serpentine pattern.
18. The method as defined in claim 10 wherein a fan is used to
drive oxygen through said conduit.
19. An apparatus for managing heat generated by a device that is
powered at least in part by a direct oxidation fuel cell comprises:
a direct oxidation fuel cell coupled to provide power to said
device; and means for managing heat generated by said device by
transferring at least some of said heat to oxygen flowing in a
conduit coupled between a source of oxygen and said fuel cell,
whereby an operating temperature of said device is regulated and an
operating temperature of said fuel cell is raised.
20. The apparatus as defined in claim 19 wherein heat is
transferred to the oxygen flowing in the conduit prior to
introduction to the fuel cell.
21. The apparatus as defined in claim 19 wherein heat is
transferred to the oxygen flowing in the conduit following
introduction to the fuel cell.
22. A thermal management system, comprising: a direct oxidation
fuel cell system; an application device which is powered at least
in part by said direct oxidation fuel cell system; an oxygen source
coupled to said direct oxidation fuel cell system; and a heat
management component coupled between said direct oxidation fuel
cell system and said application device, said heat management
component being arranged such that at least a portion of the heat
generated by the device is transferred to the oxygen, whereby an
operating temperature of said application device is regulated and
an operating temperature of said fuel cell is raised.
23. The thermal management system as defined in claim 22 wherein
said heat management component includes a conduit disposed between
said oxygen source and said fuel cell.
24. A method of regulating the temperature of a fuel cell system
including the steps of providing an application device that is
powered at least in part by a direct oxidation fuel cell system;
providing an associated oxygen source; and integrating with said
fuel cell system and said application device, a heat management
component which transfers at least a portion of the heat generated
by said device or said fuel cell system to said oxygen, whereby an
operating temperature of said fuel is regulated.
25. The method as defined in claim 24 including the further step of
providing as said heat management component a conduit coupled
between said oxygen source and said fuel cell system.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a divisional of commonly assigned
copending U.S. patent application Ser. No. 10/213,987, which was
filed on Aug. 7, 2002, by Willaim P. Acker for INTEGRATED HEAT
MANAGEMENT OF ELECTRONICS AND FUEL CELL POWER SYSTEM, and is hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to the field of fuel
cells and, more specifically, to a thermal management system that
integrates a direct methanol fuel cell (DMFC) system and a device,
in which the device is powered at least in part by the DMFC.
[0004] 2. Background Information
[0005] Fuel cells are devices in which an electrochemical reaction
is used to generate electricity. A variety of materials may be
suited for use as a fuel depending upon the materials chosen for
the components of the cell. Organic materials, such as methanol or
natural gas, are attractive choices for fuel due to their high
specific energy.
[0006] Direct oxidation fuel cell systems may be better suited for
a number of applications in smaller mobile devices (e.g., mobile
phones, handheld and laptop computers), as well as in some larger
applications. Typically, in direct oxidation fuel cells, a
carbonaceous liquid fuel in an aqueous solution (typically aqueous
methanol) is introduced to the anode face of a membrane electrode
assembly (MEA). The MEA contains a protonically conductive, but
electronically non-conductive membrane (PCM). Typically, a catalyst
which enables direct oxidation of the fuel on the anode is disposed
on the surface of the PCM (or is otherwise present in the anode
chamber of the fuel cell). Diffusion layers are typically in
contact with at least one of the catalyzed anode and cathode faces
of the PCM to facilitate the introduction of reactants and removal
of products of the reaction from the PCM, and also serve to conduct
electrons. Protons (from hydrogen found in the fuel and water
molecules involved in the anodic reaction) are separated from the
electrons. The protons migrate through the PCM, which is
impermeable to the electrons. The electrons thus seek a different
path to reunite with the protons and oxygen molecules involved in
the cathodic reaction and travel through a load, providing
electrical power.
[0007] One example of a direct oxidation fuel cell system is a
direct methanol fuel cell system or DMFC system. In a DMFC system,
methanol in an aqueous solution is used as fuel (the "fuel
mixture"), and oxygen, preferably from ambient air, is used as the
oxidizing agent. There are two fundamental half reactions that
occur in a DMFC which allow a DMFC system to provide electricity to
power consuming devices: the anodic disassociation of the methanol
and water fuel mixture into CO.sub.2, protons, and electrons; and
the cathodic combination of protons, electrons and oxygen into
water. The overall reaction may be limited by the failure of either
of these reactions to proceed to completion at an acceptable rate
(more specifically, failure to oxidize the fuel mixture will limit
the cathodic generation of water, and vice versa).
[0008] Typical DMFC systems include a fuel source, fluid and
effluent management systems, and a direct methanol fuel cell ("fuel
cell"). The fuel cell typically consists of a housing, and a
membrane electrode assembly ("MEA") disposed within the housing. A
typical MEA includes a centrally disposed protonically conductive,
electronically non-conductive membrane ("PCM") such as Nafion.RTM.,
a registered trademark of E.I. Dupont de Nours and Company, which
is a cation exchange membrane comprised of perfluoro sulfonic acid,
in a variety of thicknesses and equivalent weights. The PCM is
typically coated on each face with an electrocatalyst such as
platinum, or platinum/ruthenium mixtures or alloy particles. On
either face of the catalyst coated PCM, the MEA typically includes
a diffusion layer. The diffusion layers function to evenly
distribute the liquid and gaseous reactants to, and transport the
liquid and gaseous products of the reactions from the catalyzed
anode face of the PCM, or the gaseous oxygen from air or other
source across the catalyzed cathode face of the PCM. The diffusion
layers also facilitate the collection of electrons and conduction
to the device being powered. In addition, flow field plates may be
placed on the aspect of each diffusion layer that is not in contact
with the catalyst-coated PCM to provide mass transport of the
reactants and by products of the electrochemical reactions and also
have a current collection functionality to collect and conduct
electrons through the load.
[0009] One problem with electronic systems and components,
including those which may be powered by DMFC systems, is that
electronic components and subsystems can become overheated, and
their performance compromised. This problem is especially difficult
to effectively address in small mobile devices where electronic
components are packed tightly together and space, weight, and
volume are critical design criteria. In such devices, it is
desirable to minimize the number of components dedicated to cooling
the system. Also, as mobile devices become more powerful and
require more power, mobile device components produce increasing
amounts of heat. Accordingly, it is increasingly important to
remove heat from the electronic components and systems.
[0010] DMFCs are efficient at dissipating heat that is generated
within the system, due to the fact that there are several fluids
present in the system, and due to the fact that air is exchanged
within the fuel cell system, allowing for a more natural heat
exchange. In addition, the direct oxidation fuel cell systems and
DMFCs demonstrate increased current generation (at a given voltage)
at higher temperatures due to the increased kinetics of the
reactions. Thus, if additional heat is applied to the reaction, the
DMFCs can become an even more suitable power source.
[0011] It is thus an object of the invention to provide a thermal
management system that provides temperature regulation of a device
powered at least in part by a DMFC system, in which excess heat
produced by the device is transferred to the DMFC. As a result of
this heat transfer, the temperature of the device is kept within a
desired range and the operation of the DMFC is improved.
SUMMARY OF THE INVENTION
[0012] In brief summary, the present invention provides a thermal
management system that integrates a direct methanol fuel cell
system and a device which is powered at least in part by the DMFC
system. The invention provides the ability to transfer heat from
the device to the DMFC system, which results in at least two
benefits: the operating temperature of the device is regulated, and
the DMFC's performance is enhanced.
[0013] In a first embodiment, the DMFC or some of its components
are placed in contact with the device, allowing for the conduction
of heat from the device to the DMFC. This is preferably achieved by
placing at least one aspect of the housing of the DMFC system in
direct contact with the device or by passing reactants close to the
device before the reactants are reacted within the DMFC. A similar
approach based on heat transfer via a small fluid gap, wherein heat
is transferred through air or a "thermal grease" is also
contemplated. In a second embodiment, thermally conductive
components are preferably integrated into the device to transfer
heat from the device to the DMFC system, allowing better heat
transfer.
[0014] In a third embodiment, air may be directed over the device
before introduction to the cathode face of the DMFC, depending on
the desired heat or humidity characteristics. If air is directed
over the device before introduction to the cathode face, it will
remove heat from the heat generating electronics and increase the
operating temperature of the DMFC, and tend to improve the kinetics
of the reaction and the fuel cell system.
[0015] In a fourth embodiment, a pump in the DMFC is preferably
used to circulate a dedicated coolant (i.e. not one of the
reactants) through the device. The coolant removes heat produced by
the device and transfers it to the DMFC where the heat is applied
to the reactants.
[0016] In a fifth embodiment, a heat pump is used to transfer heat
from the device, which heat is used in turn to vaporize the
reactants. The vaporized reactants are condensed within the DMFC
system prior to being reacted, thereby transferring heat to the
DMFC.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention description below refers to the accompanying
drawings, of which:
[0018] FIG. 1 is a block diagram of a direct methanol fuel cell
system known in the prior art;
[0019] FIG. 2A is a schematic representation of fluid flow within
the device powered by a fuel cell system;
[0020] FIG. 2B is a block diagram of a direct methanol fuel cell
system, constructed in accordance with a preferred embodiment of
the present invention, in which heat generated by an device is
regulated in accordance with the invention;
[0021] FIG. 3A is a perspective diagram of a device in which both
the direct methanol fuel cell system powering the device and a
heat-generating portion of said device are enclosed by a common
housing;
[0022] FIG. 3B is a perspective diagram of a device in which the
direct methanol fuel cell system powering the device and a
heat-generating portion of said device are enclosed by discrete
housings;
[0023] FIG. 4 is a block diagram of a direct fuel cell system in
which a thermally conductive material is used to manage heat
generated by a device;
[0024] FIG. 5A is a block diagram of a direct methanol fuel cell
system in which heat generated by a device is managed by
transferring heat to fuel circulated in proximity to the
device;
[0025] FIG. 5B is a block diagram of a direct methanol fuel cell
system in which heat generated by a device is managed by
transferring heat to a dedicated coolant circulated in proximity to
the device;
[0026] FIG. 6 is a block diagram of a direct methanol fuel cell
system in which heat generated by a device is managed by
transferring heat to air circulated through device;
[0027] FIG. 7 is a perspective drawing of a circuit board in which
heat is managed by conduction through a conduit running over the
processor, carrying reactants to the direct methanol fuel cell or a
pump, or a dedicated coolant to the pump;
[0028] FIG. 8A is a perspective drawing of a circuit board in which
heat is managed by conduction in which a conduit carries reactants
to the direct methanol fuel cell or a pump, or a dedicated coolant
to the pump;
[0029] FIG. 8B is a perspective drawing of a circuit board in which
heat is managed by conduction through a conduit running under a
processor mounted on the circuit board;
[0030] FIG. 9 is a perspective drawing of a circuit board in which
heat is managed by conduction through a conduit running around the
sides of the processor;
[0031] FIG. 10 is a block diagram of a direct methanol fuel cell
system in which heat is managed by a heat pump/valve.
DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT
[0032] An example of a direct oxidation fuel system 20 is
schematically illustrated in FIG. 1. The fuel cell system 20
includes a direct oxidation fuel cell, which may be a direct
methanol fuel cell 21 ("DMFC"), for example. For purposes of
illustration, and not by way of limitation, we herein describe an
illustrative embodiment of the invention with DMFC 21, or DMFC
system with the fuel substance being methanol or an aqueous
methanol solution. However, it is within the scope of the present
invention that other carbonaceous fuels such as ethanol, or
combinations of carbonaceous fuels and aqueous solutions thereof
may be used. It should be further understood that the invention is
applicable to any fuel cell system where it is preferable to
introduce a liquid fuel or component thereof to the anode aspect 26
of the membrane electrode assembly (MEA) 25 and not simply the
embodiments described in FIG. 1.
[0033] The system 20, including the DMFC 21, has a fuel delivery
system to deliver fuel from fuel source 22. The DMFC 21 includes a
housing 23 that encloses a MEA 24. MEA 24 incorporates protonically
conductive, electronically non-conductive, membrane (PCM) 25, and
typically includes at least one diffusion layer in contact with one
or both aspects of the PCM 25. PCM 25 has an anode face 26 and
cathode face 27, each of which may be coated with a catalyst,
including but not limited to platinum, or a blend of platinum and
ruthenium. Diffusion layers are usually fabricated from carbon
cloth or carbon paper that are treated with a mixture of
Teflon.RTM. and high surface area carbon particles, are typically
provided and in intimate contact with the catalyzed faces of each
of the anode 26 and cathode 27 aspects of the PCM 25, though the
invention is not limited to systems that require diffusion layers.
The portion of DMFC 21 defined by the housing 23 and the anode face
26 of the PCM 25 is referred to herein as the anode chamber 28. The
portion of DMFC 21 defined by the housing 23 and the cathode face
27 of the PCM 25 is referred to herein as the cathode chamber 29.
The anode chamber 28 and cathode chamber 29 may further contain a
flow field plate or plates (not shown) in contact with the
diffusion layer, in order to manage the mass transport of reactants
and products of the reaction. Those skilled in the art will
recognize that the catalyst may be applied to the PCM 25 by
applying a suspension containing the catalyst to PCM 25. As used
herein the terms "anode face" and "cathode face" may refer to the
catalyzed faces of the PCM 25, and shall include any residual
catalyst materials that may remain on the surface of the PCM 25 as
the result of such application.
[0034] As will be understood by those skilled in the art,
electricity-generating reactions occur when a carbonaceous fuel
mixture, including, but not limited to methanol or an aqueous
methanol solution is introduced to the anode face 26, and oxygen,
usually from ambient air, is introduced to the cathode face 27.
More specifically, a carbonaceous fuel mixture from fuel source 22
is delivered by pump 30 to the anode chamber 28 of the DMFC 21. The
fuel mixture passes through channels in the flow field plate (or is
present in the anode chamber 28), and/or a diffusion layer, and is
ultimately presented to the anode face 26 of the PCM 25. Catalysts
on the membrane surface (or which are otherwise present within the
MEA 24) enable the anodic oxidation of the carbonaceous fuel on the
anode face 26, separating hydrogen protons and electrons from the
fuel and water molecules of the fuel mixture. Upon the closing of a
circuit, protons pass through PCM 25, which is impermeable to the
electrons. The electrons thus seek a different path to reunite with
the protons, and travel through a load 31 of an external circuit,
thus providing electrical power to the load 31. So long as the
reactions continue, a current is maintained through the external
circuit. Direct oxidation fuel cells produce water (H.sub.2O) and
carbon dioxide (CO.sub.2 ) as products of the reaction, which must
be directed away from the catalyzed anode and cathode membrane
surfaces 26, 27. The gas separator 32 separates the excess air and
water vapor from the water. This water can be later directed to the
pump 30 via a flow path 33. Those skilled in the art will recognize
that the gas separator 32 may be incorporated into an existing
component within the DMFC 21 or the DMFC system 20.
[0035] FIG. 2A shows a more general schematic representation of the
flow of the reactant from the fuel source 22 over the
heat-generating portion 46 of the device, prior to delivering the
reactant to the DMFC 21.
[0036] FIG. 2B shows an electronic device 40 which is powered at
least in part by a direct methanol fuel cell system 62 placed in
contact with or proximity to heat generating portion 46 of the
device 40, thus enabling the conduction of heat from portion 46 to
the DMFC 42 or related components. The DMFC system 62 may also
include a battery, capacitor or other power storage device (not
shown). Electronic device 40 may represent, for example, a wireless
phone, notebook computer or any of a variety of other devices,
which may be powered by a fuel cell. In this illustrative
embodiment, some or all of a housing 52 of the DMFC 42, a gas
separator 44, and conduits 47-50 and 53 that direct both the flow
of reactants to the DMFC 42 and the flow of products from the DMFC
42 are preferably placed in direct contact with or in proximity to
the portion 46. By placing conduits 47-50 and 53 in contact with or
in proximity to portion 46, the conduits may conduct heat from
portion 46, thereby heating the reactants flowing through the
conduits. A similar approach based on convection may be used as
well, as heat may be transferred from portion 46 to the DMFC 42 or
related components indirectly.
[0037] FIGS. 3A and 3B show different configurations of a device
powered at least in part by a DMFC system 62. In FIG. 3A, a single
housing 64 contains both the DMFC system 62 powering the device 64
and the heat-generating portion 46 of said device 64, as well as
other components which provide functionality. In FIG. 3B, the DMFC
system 62 is not enclosed in the same housing that encloses the
device 68. These are just two of many possible configurations
recognizable to those skilled in the art. These figures are
lustration and not intended to limit or proscribe any possible
couplings of the heat generating portion of a device to the DMFC
system.
[0038] FIG. 4 shows a second embodiment of the present invention in
which a thermally conductive material 61, preferably made of a
polymer but other materials such as metal could be used as well, is
positioned between DMFC 42 (and possibly related components) and
heat-generating portion 46, allowing for the transfer of heat from
the portion 46 to DMFC 42. Those skilled in the art will appreciate
that conductive material 61 may be placed in contact with some or
all of other components (pump 43, gas separator 44, various
conduits) in order to achieve a desired heat transfer rate,
packaging requirements or other requirements of a particular
application. Though the DMFC system 62 and the heat-generating
portion 46 are shown as being in contact on a single plane, those
skilled in the art will recognize that the interface may take place
on more than one aspect between the heat generating portion 46 and
the fuel cell system 62. Those skilled in the art will further
recognize that the heat conducting material 61 may simply be
comprised of an air gap and/or a "thermal grease".
[0039] FIG. 5A shows a third embodiment in which a conduit 71
between the fuel source 41 and the pump 43 is routed in proximity
to heat-generating portion 46. Conduit 71 is preferably arranged in
an elongated, serpentine configuration such that it presents a
large surface area for heat transfer between heat generating
portion 46 and the fuel in the conduit 71. The transferred heat
increases the temperature of the fuel flowing in conduit 71, thus
effectively transferring heat to DMFC 45. Conduit 71 may
alternatively be placed in direct contact with portion 46, similar
to FIG. 2. Conduit 71 is in substantially the same plane as the
portion 46, though there may be instances where the conduit 71
extends along more than one aspect of the portion 46. Those skilled
in the art will recognize that it is possible to implement conduits
containing water or other reactants in a substantially similar
fashion. Other variations include, but are not limited to,
eliminating the gas separator 44, or anode fuel and recirculation
components (conduits 50 and 53) so that the heat is conducted to
the fuel after it leaves the fuel source 41 but before it enters
the fuel cell 42. FIG. 5B shows an alternative embodiment in which
fuel is delivered directly to a pump 82 which circulates a fluid
through the heat-generating portion 46 in conduit 81. The fluid may
be either; 1) a reactant; or 2) a dedicated coolant utilizing a
separate, closed loop system (not shown) and may be used to absorb
heat from the heat generating portion 46 and transmit it to the
DMFC 42 after passing through conduit 81. The fluid is eventually
returned to the pump 82 where heat may be transferred to the
reactants that pass into the DMFC 42, or if the fluid is a
reactant, it may be delivered to the DMFC 42.
[0040] FIG. 6 illustrates a fourth embodiment in which air passes
through a conduit 91 in proximity to heat-generating portion 46,
allowing heat to be transferred to the air before it is introduced
to the DMFC 42. Like in the embodiment of FIG. 5A, a serpentine
configuration of conduit 91 is preferable as this increases the
surface area available for heat transfer, though other
configurations are also within the scope of the invention. This
embodiment may require a component to assist in air induction, such
as a fan (not shown) to increase the volume of air that passes
through the cathode chamber of the fuel cell 42. By introducing
warmer air into the cathode of the DMFC 42, the kinetics of the
cathodic reaction is enhanced, and performance of the DMFC 42 is
increased.
[0041] It is further possible to integrate the fluidic components
with the heat-generating portion 46 of the device, if the DMFC
system and the portion are mechanically integrated. FIGS. 7, 8A, 8B
and 9 show different arrangements of conduits 102, 110, 111 or 112
passing in proximity to heat-generating components. In FIG. 7,
conduit 102 passes over a processor 104, which is connected to a
printed circuit board 106 by leads 108. Heat produced by the
processor 104 is transferred to the conduit 102, which in turn
transfers heat to the fluid flowing through the conduit 102 en
route to or from the DMFC (not shown). In FIG. 8A, conduit 110
passes under processor 104. In FIG. 8B, conduit 111 passes under
processor 104 in a channel or saddle 107 in the printed circuit
board 105. In FIG. 9, conduit 112 passes around the sides of
processor 104. In FIGS. 7-9 reactants may be routed though conduits
102, 110, 111 and 112 before being routed to the pump (not shown)
or to the DMFC (not shown). Alternatively, a dedicated coolant may
be routed through conduits 102, 110, 111 and 112.
[0042] FIG. 10 shows a fifth embodiment in which a simple heat
pump/valve 122 is used to assist is pumping vaporized reactants to
DMFC 121. Heat is transferred from the heat-generating portion 46
to the heat pump/valve 122, which in turn transfers heat to the
reactants entering the heat pump/valve 122 via conduit 123. This
may result in the reactants being vaporized, after which they are
routed to the DMFC 121 via conduit 124. The vaporized reactants
then condense, or are reacted in vapor phase, within the DMFC 121
prior to being reacted, thereby transferring heat to the DMFC
121.
* * * * *