Patent Application
20140255733
Vast numbers of people travel every day via aircraft, trains, buses, and other commercial vehicles. Such commercial vehicles are often outfitted with components that are important for passenger comfort and satisfaction. For example, commercial passenger aircraft can have catering equipment, heating/cooling systems, lavatories, water heaters, power seats, passenger entertainment units, lighting systems, and other components. A number of these components on-board an aircraft require electrical power for their activation. Although many of these components are separate from the electrical components that are actually required to run the aircraft (i.e., the navigation system, fuel gauges, flight controls, and hydraulic systems), an ongoing concern with these components is their energy consumption. Frequently, such systems require more power than can be drawn from the aircraft engines' drive generators, necessitating additional power sources, such as a kerosene-burning auxiliary power unit (APU) (or by a ground power unit if the aircraft is not yet in flight). Energy from these power sources may have to travel a significant distance to reach the power-consuming components, resulting in loss of power during transmission and a reduction in overall efficiency of power systems. The total energy consumption can also be rather large, particularly for long flights with hundreds of passengers, and may require significant amounts of fossil fuels for operation. Additionally, use of aircraft power typically produces noise and CO2 emissions, both of which are desirably reduced.
The relatively new technology of fuel cell systems provides a promising cleaner and quieter means to supplement energy sources already aboard commercial crafts. A fuel cell system produces electrical energy as a main product by combining a fuel source of liquid, gaseous, or solid hydrogen with a source of oxygen, such as oxygen in the air, compressed oxygen, or chemical oxygen generation. A fuel cell system has several outputs in addition to electrical power, and these other outputs often are not utilized and therefore become waste. For example, thermal power (heat), water, and oxygen-depleted air (ODA) are produced as by-products. These by-products are far less harmful than CO2 emissions from current aircraft power generation processes.
Furthermore, significant variations in operating conditions for fuel cell systems may occur. Such variations may lead to unpredictability regarding the amount of resources needed for a particular flight, reduce efficiency of the fuel cell systems, and/or otherwise negatively affect operation of components aboard the craft. As such, systems that may be implemented to further enhance the functionality of fuel cell systems aboard aircraft are desirable for improving efficiency and operational life of components aboard the craft.
The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.
As an example embodiment, disclosed is a fuel cell system for an aircraft. The fuel cell system can include a hydrogen storage vessel, a fuel cell assembly, and a catalyst system. The fuel cell assembly can be configured to receive a hydrogen input comprising hydrogen from the hydrogen storage vessel, receive an oxygen input comprising a fluid having an initial oxygen content, and convert the hydrogen input and the oxygen input so as to yield a number of products. The products can include a water product comprising water, a heat product comprising heat, an oxygen-depleted product comprising the fluid having a second oxygen content lower than the initial oxygen content, and an electric product comprising electrical power. The fuel cell assembly can supply any combination of these products to one or more operational systems of the aircraft. The catalyst system can receive and combust hydrogen from the fuel cell assembly and/or the hydrogen storage vessel. The hydrogen combustion can treat exhaust from the fuel cell system and/or provide heat for warming water (such as for operational systems of the aircraft) and/or for warming fuel cell system components (such as during a start-up phase).
In a further example embodiment, a method is provided for distributing heat from a catalyst system associated with a fuel cell system for an aircraft. The method can include providing a fuel cell system and a catalyst system aboard an aircraft, generating heat via the catalyst system, and routing the generated heat to the fuel cell system, a hydrogen storage vessel, and/or a water source for an operational system of the aircraft.
For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings.
The specification makes reference to the following appended figures, in which use of like reference numerals in different figures is intended to illustrate like or analogous components.
In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiment being described.
Disclosed herein are fuel cell systems used as a power source aboard aircraft and utilizing catalytic burner systems. For example, catalytic burner systems integrated with fuel cell systems may be configured to reduce unconsumed fuel in exhaust, to heat water for use aboard the aircraft, and/or to regulate operating temperatures of components associated with the fuel cell systems. While such fuel cell technology is discussed herein in relation to use in aircrafts, it is by no means so limited and may be used in buses, trains, spacecraft, or other forms of transportation equipped with fuel cell systems.
A fuel cell system is a device that converts chemical energy from a chemical reaction involving hydrogen or other fuel source and oxygen-rich gas (e.g., air) into electrical energy. As illustrated in
Any appropriate fuel cell system 100 may be used, including, but not limited to, a Proton Exchange Membrane Fuel Cell (PEMFC), a Solid Oxide Fuel Cell (SOFC), a Molten Carbonate Fuel Cell (MCFC), a Direct Methanol Fuel Cell (DMFC), an Alkaline Fuel Cell (AFC), or a Phosphoric Acid Fuel Cell (PAFC). Any other existing or future fuel cell system technology, including, but not limited to, a hybrid solution, may also be used. Although any appropriate fuel cell system 100 may be used, several features and functions shared by many of the aforementioned fuel cell systems may be appreciated with reference to
The fuel cell system 200 depicted in
At the cathode 206, oxygen 226 is provided via a cathode intake 228 (shown by arrow 240), electrons 214 are communicated via the conductive path 222 (shown by arrow 220), and hydrogen ions 208 are introduced via the electrolyte 204 (shown by dashed arrow 218). Water 232 is formed in a second chemical reaction by the combination of said oxygen 226, hydrogen ions 212, and electrons 214 (reaction shown by dotted arrows 242). The presence of a second catalyst 230 may be utilized to facilitate and/or increase a rate of this second chemical reaction. The water 232 and any excess oxygen 226 are transferred out of the cathode 206 via a cathode exhaust outlet 234 (shown by arrows 244 and 246). Excess hydrogen 208 is transferred out of the anode 202 via an anode exhaust outlet 236 (shown by arrow 248). Heat may also be produced in the fuel cell system 200 (such as via the first chemical reaction and/or the second chemical reaction) and utilized in various applications aboard the aircraft, along with the water, the electrical power, and the oxygen depleted gas produced by the fuel cell system 200.
Aircraft-based fuel cell systems (such as fuel cell systems 100 and/or 200) can be configured to operate with catalytic burner systems to provide various functions, which may include those functions discussed in more detail with respect to
The catalytic burner system 300 can include a catalyst layer 302, a hydrogen inlet 304, an oxygen inlet 306, and a system exhaust 308. The catalyst layer 302 can include a catalyst that can induce oxygen and hydrogen to undergo a combustion reaction at a lower temperature and/or in less time than in the absence of the catalyst. The presence of the catalyst may allow hydrogen and oxygen to combust without a spark or other ignition source. In some aspects, a catalytic burner system 300 can produce a greater amount of heat than is produced by consuming an equivalent amount of hydrogen in a fuel cell system (such as fuel cell system 100 or 200, described above with respect to
The catalyst layer 302 can be coupled with a heating element 312. Non-limiting examples of the heating element 312 include an electric wire grid and/or coil. The heating element 312 can be coupled with a power source 314. Non-limiting examples of the power source include an electrical energy storage device (such as a battery or a capacitor), a generator (including, but not limited to, an aircraft-based fuel cell system), a power grid (such as a power network of an aircraft), and combinations thereof. Energy communicated from the power source 314 can increase the temperature of the heating element 312, which can in turn raise the temperature of the catalyst in the catalyst layer 302.
The catalyst layer 302 can be positioned in a chamber 310. The hydrogen inlet 304 can introduce hydrogen toward the catalyst layer 302 (shown by arrow 318), such as into the chamber 310. In some aspects, the hydrogen may be provided in the form of a fuel containing hydrogen, such as the fuel used for the fuel cell system 200. Additionally or alternatively, the hydrogen may be provided via the anode exhaust outlet 236 described above with respect to
The hydrogen inlet 304 and the oxygen inlet 306 can be arranged such that the introduced hydrogen and oxygen mix in the presence of the catalyst in the catalyst layer 302. The heating element 312 can be utilized to increase the temperature of the catalyst in the catalyst layer 302 to a level suitable for facilitating combustion of the mixing hydrogen and oxygen. The combustion reaction of the introduced hydrogen and oxygen can produce heat and water. In some aspects, heat from the combustion process can maintain the suitable temperature of the catalyst layer 302, and the heating element 312 can be deactivated after the combustion process is initiated. Water products from the combustion process (such as water vapor, steam, and/or water droplets) and any unconsumed gas can be released from the catalytic burner system 300 via the system exhaust 308 (shown by arrow 322). As may be appreciated, the hydrogen content of matter passing through the catalytic burner system 300 can be significantly reduced and/or eliminated as a result of the catalytic combustion therein.
The catalytic burner system 300 may also include a heat transfer network 316. For example, the heat transfer network 316 may include pipes and/or other lines for conveying coolant fluid. In some aspects, the heat transfer network 316 may include a pump 324 configured to move the coolant fluid through the heat transfer network 316. In additional and/or alternative aspects, the coolant fluid may flow as a result of variations in temperature of the coolant fluid. In some aspects, lines of the heat transfer network 316 may overlap or be interwoven through the catalyst layer 302. Heat from the combustion process in the catalytic burner system 300 may be transferred to the coolant fluid as the coolant fluid passes through portions of the heat transfer network 316 that are arranged within a space in which combustion occurs, such as the chamber 310. The heat transfer network 316 can carry the heat via the coolant fluid to provide heat to another component, such as via a heat exchanger associated with the component. In some aspects, the chamber 310, heat transfer network 316, and/or the component to receive the heat are arranged closely together so as to minimize a distance and concomitant heat loss between objects.
Catalyst systems (such as, but not limited to, the catalytic burner system 300 described above with reference to
An outlet for exhaust 404 of a fuel cell assembly 406 can be coupled with the catalyst system 402. For example, the outlet for exhaust 404 may correspond to the anode exhaust outlet 236 and/or the cathode exhaust outlet 234 described above with respect to
Reducing the level of hydrogen conveyed in the exhaust 404 can reduce the risk of uncontrolled combustion of such hydrogen. Reducing the level of hydrogen can also allow exhaust from the cathode exhaust outlet 234 and the anode exhaust outlet 236 to be safely mixed. In some aspects, the outlet for exhaust 404 may be coupled with the catalyst system 402 in such a manner that exhaust from the anode exhaust outlet 236 and exhaust from the cathode exhaust outlet 234 are prevented from mixing until fully treated by the catalyst system 402. For example, exhaust from the anode 202 may be routed through the catalyst system 402 (i.e., so as to undergo a combustion reaction that consumes excess hydrogen) before mixing with exhaust from the cathode 206 that is routed so as to not undergo a combustion reaction in the catalyst system 402. In another example, exhaust from the cathode 206 and exhaust from the anode 202 are each routed through separate catalyst systems 402 before being combined. In some aspects, exhaust from the anode 202 and the cathode 206 are routed together into the catalyst system 402 for controlled combustion therein.
The fuel cell system 500 can include a water heat exchanger 516. Hydrogen from the hydrogen store 508, from the exhaust 504 of the fuel cell assembly 506, or from some combination thereof can be combusted in the catalyst system 502 to produce heat 524. The heat 524 can be conveyed into the water heat exchanger 516, such as via the heat transfer network 316 described above with respect to
As may be appreciated from the following illustrative examples, the temperature difference between the heated water 522 and the water initially introduced into the water heat exchanger 516 may depend upon the volume of water and the amount of heat 524 introduced into the water heat exchanger 516. Additionally, the amount of water and/or the amount of heat 524 conveyed to the water heat exchanger 516 can be controlled to yield a heated water 522 output of a desired volume and/or temperature. Heated water 522 of different volumes and/or temperatures may be desired for a variety of differing uses, including, but not limited to providing warmed hand-washing water, providing warmed water to prevent freezing of on-board pipes and conduits, providing hot water for a beverage maker (such as a coffee or espresso maker), providing warm water for a shower, providing hot water for washing dishes, providing steam for cooking ovens, and providing steam for sanitation purposes.
In a first illustrative example, water from the water store 514 is introduced (i.e., arrow 518) into the water heat exchanger 516 at an ambient temperature of approximately 20° C., and heat 524 transferred from the catalyst system 502 is harnessed to produce heated water 522 having a temperature of approximately 60° C. (such as may be useful for use in the lavatory 182 discussed above with regards to
The hydrogen store 608 may supply hydrogen to the catalyst system 602 (as shown by arrow 628) to produce heat 630 and/or 632. The catalyst system 602 can be configured to convey the heat 630 and/or 632 to various components of the fuel cell system 600 (such as, but not limited to, the hydrogen store 608, and/or other subcomponents of the fuel cell assembly 606 and/or its ancillaries). For example, the fuel cell system 600 (or parts thereof) may undergo frozen or cold condition during operation, storage, and/or any other life cycle phase. Any components containing water may be damaged or rendered inoperable due to ice forming from the water experiencing temperatures below freezing. Utilizing the catalyst system 602 to heat the components in such scenarios may prevent damage or inoperability of the fuel cell system 600 or parts thereof. For example, the catalyst system 602 may be initiated before the rest of the fuel cell system 600 in order to provide heat 630 and/or 632 that may melt ice that might otherwise prevent the fuel cell system (or components thereof) from starting.
In some aspects, components of the fuel cell system 600 may operate at a greatest efficiency when operating within a certain temperature range. The catalyst system 602 may provide the heat 630 and/or 632 for regulating the temperature of such a component within the desired temperature range. For example, the heat 630 and/or 632 can be conveyed to the component to increase a temperature into the desired range. Alternatively, the heat 630 and/or 632 may be utilized with heat-driven cooling devices (such as absorption chillers) to decrease a temperature into the desired range.
In some aspects, the fuel cell system 600 can be configured to selectively perform the functions described with regards to
In embodiments, any of the entities described herein may be embodied in part or in whole by a computer that performs any or all of the functions and operations disclosed.
The software components or functions described in this application may be implemented via programming logic controllers (“PLCs”), which may use any suitable PLC programming language. In other embodiments, the software components or functions described in this application may be implemented as software code to be executed by one or more processors using any suitable computer language such as, for example, Java, C++ or Perl using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions or commands on a computer-readable medium, such as a random access memory (“RAM”), a read-only memory (“ROM”), a magnetic medium such as a hard-drive or a floppy disk, an optical medium such as a CD-ROM, or a DNA medium. Any such computer-readable medium may also reside on or within a single computational apparatus, and may be present on or within different computational apparatuses within a system or network.
Aspects of the invention can be implemented in the form of control logic in hardware (circuitry, dedicated logic, etc.), software (such as is run on a general purpose computing system or a dedicated machine), firmware (embedded software), or any combination thereof. The control logic may be stored in an information storage medium as a plurality of instructions adapted to direct one information processing device or more than one information processing devices to perform a set of operations disclosed in embodiments of the invention. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the invention.
According to certain embodiments, the operation of one or more systems described herein is illustrated in a simplified flow diagram shown in
Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
This application claims the benefit of U.S. Provisional Application No. 61/774,955, entitled “FUEL CELL SYSTEM WITH INTEGRATED CATALYTIC BURNER,” Mar. 8, 2013 (Attorney Docket No. 41052/869352 or 93358-869352), the entire disclosure of which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61774955 | Mar 2013 | US |
