Fuel Cell Auxiliary

For the fuel cell power plants, the economic and lifetime related issues hinder the acceptance of fuel cell technologies. Such problems were not associated with fuel cells but with auxiliary fuel cell units such as thermal management, reactant storage, and water mans emenL Therefore, the auxiliary units of fuel cell systems should be further developed to address these issues. 

The fuel eell is a nineteenth eentuiy invention in the twentieth eentury it heeame the heart of an eleetroehemical power plant and power souree, whieh is now in a stage of advaneed technology development. Its first and only applieation since the early 1960s, has been as an auxiliary power souree for spaee flights by the National Aeronautics and Space Administration (NASA). During the past decade, development for terrestrial (eivihan and defense) applieations has led to its commercialization and research on utilization in a variety of applications. Programs in the United States, Japan, Europe, and some other eoimtries are focused on the development of fuel cell power plant/power sources for (1) base-load,... 

Cathodic hydrogen evolution is one of the most common electrochemical reactions. It is the principal reaction in electrolytic hydrogen production, the auxiliary reaction in the production of many substances forming at the anode, such as chlorine, and a side reaction in many cathodic processes, particularly in electrohydrometallurgy. It is of considerable importance in the corrosion of metals. Its special characteristic is the fact that it can proceed in any aqueous solution particular reactants need not be added. The reverse reaction, which is the anodic ionization of molecular hydrogen, is utilized in batteries and fuel cells. 

For energy security reasons, the presence of an auxiliary power supply unit is necessary. This unit can be preferably either a hydrogen internal combustion engine (H2 ICE) or a fuel cell of corresponding capacity to meet at least the minimum needs of the system. In this case, the system is an autonomous power plant. Figure 5.11 shows a stand-alone wind-hydrogen system that is autonomous. The dashed line in some parts of it implies that these connections may not exist as well. The DC/AC converter/controller should have the capability to operate vice versa and power up the lines through the power controller. 

The modular design of the HyPM fuel cells allows scaling for higher power requirements using a variety of configurations, such as series and parallel systems. Potential applications for the technology include vehicle propulsion, auxiliary power units (APU), stationary applications including backup and standby power units, combined heat and power units and portable power applications for the construction industry and the military. 

GM has provided the U.S. Army with a diesel hybrid military pickup truck equipped with a fuel cell auxiliary power unit that could become the... 

Freightliner and the U.S. Department of Energy Advanced Vehicles Program are exploring using fuel cell auxiliary power units (APUs) in lieu of main engine idling in their vehicles. The truck auxiliary power application may offer a viable near-term market for small (1- 5-kW) fuel cells. 

Ballard does not build cars, trucks, or buses. Its sole product is the fuel cell in all of its many applications, plus the auxiliary equipment to make them work. Since Ballard is a pioneer in modern fuel cells its technology is advanced and its fuel cell sales have made it one of the fastest-growing automotive suppliers in the world with alliance partners including DaimlerChrysler, Ford, Honda, Nissan, Mazda, Volvo, and Volkswagen. 

This is consistent with a fuel-cell drive train (the fuel cell, hybrid battery, motor and auxiliaries) manufacturing cost of about 50/kW, and hydrogen-storage cost of 10/kWh, and a retail price mark-up factor of 1.4 (i.e., the retail price is 1.4 times the manufacturing cost). 

We discuss both the Proton Exchange Membrane as well as the Solid Oxide Fuel Cells in this chapter (PEMFC and SOFC). Both types are in full development, the PEMFC for mobile and stationary applications, and the SOFC for stationary applications as well as for auxiliary power generation for transport. 

Andrukaitis, E., Fuel Cells for Auxiliary Mobile Power in the Military, Poster 93 Proceedings of the Fuel Cell Seminar 2005, 14-18 November 2005... 

Therefore, methanol is the top candidate because of its low price, less toxicity, high energy density and easy handling. Although direct methanol fuel cells may need an auxiliary system to treat unoxidized or partially oxidized fuel in the exhaust gas, direct methanol fuel cells are still a very attractive system as a portable power source. 

Fuel cells are an important technology for a potentially wide variety of applications including micropower, auxiliary power, transportation power, stationary power for buildings and other distributed generation applications, and central power. These applications will be in a large number of industries worldwide. 

This edition of the Fuel Cell Handbook is more comprehensive than previous versions in that it includes several changes. First, calculation examples for fuel cells are included for the wide variety of possible applications. This includes transportation and auxiliary power applications for the first time. In addition, the handbook includes a separate section on alkaline fuel cells. The intermediate temperature solid-state fuel cell section is being developed. In this edition, hybrids are also included as a separate section for the first time. Hybrids are some of the most efficient power plants ever conceived and are actually being demonstrated. Finally, an updated list of fuel cell URLs is included in the Appendix and an updated index assists the reader in locating specific information quickly. 

In addition to high-profile fuel cell applications such as automotive propulsion and distributed power generation, the use of fuel cells as auxiliary power units (APUs) for vehicles has received considerable attention (see Figure 1-9). APU applications may be an attractive market because it offers a true mass-market opportunity that does not require the challenging performance and low cost required for propulsion systems for vehicles. In this section, a discussion of the technical performance requirements for such fuel cell APUs, as well as the current status of the technology and the implications for fuel cell system configuration and cost is given. 

Auxiliary power units are devices that can provide all or part of the non-propulsion power for vehicles. Such units are already in widespread use in a range of vehicle types and for a variety of applications, in which they provide a number of potential benefits (see Figure 1-10). Although each of these applications could provide attractive future markets for fuel cells, this section will focus on application to on-road vehicles (specifically trucks). 

Once these niche markets were exploited to start fuel cells on their development path, it became apparent that, as stated above, it was necessary to target widespread potential applications while keeping technology development as simple as possible. General application areas of present interest to the fuel cell community are multi-kWe residential, commercial, and light industrial stationary power, transportation prime and auxiliary power, and military uses. 

Electric Power System Design For specific applications, fuel cells can be used to supply DC power distribution systems designed to feed DC drives such as motors or solenoids, controls, and other auxiliary system equipment. The goal of the commercial fuel cell power plant is to deliver usable AC power to an electrical distribution system. This goal is accomplished through a subsystem that has the capability to deliver the real power (watts) and reactive power (VARS) to a facility s internal power distribution system or to a utility s grid. The power conditioning... 

The selection of a specific fuel cell pressure will affect numerous design parameters and considerations such as the current collector width, gas flow pattern, pressure vessel size, pipe and insulation size, blower size and design, compressor auxiliary load, and the selection of a bottoming cycle and its operating conditions. 

The designer has the ability to increase the overall utilization of fuel (or the oxidant) by recycling a portion of the spent stream back to the inlet. This increases the overall utilization while maintaining a lower per pass utilization of reactants within the fuel cell to ensure good cell performance. The disadvantage of recycling is the increased auxiliary power and capital cost of the high temperature recycle fan or blower. 

Speeehia, S., Tillemans, F.W.A., van den Oosterkamp, PR, Saracco, G. 2005. BIOFEAT Conceptual design and selection of a biodiesel fuel processor for a vehicle fuel cell auxiliary power unit. J Power Sources 145 683-690. 

A fuel cell is an electrochemical conversion device that has a continuous supply of fuel such as hydrogen, natural gas, or methanol and an oxidant such as oxygen, air, or hydrogen peroxide. It can have auxiliary parts to feed the device with reactants as well as a battery to supply energy for start-up. 

As noted in the Introduction, one of the defining characteristics of any fuel-cell model is how it treats transport. Thus, these equations vary depending on the model and are discussed in the appropriate subsections below. Similarly, the auxiliary equations and equilibrium relationships depend on the modeling approach and equations and are introduced and discussed where appropriate. The reactions for a fuel cell are well-known and were introduced in section 3.2.2. Of course, models modify the reaction expressions by including such effects as mass transfer and porous electrodes, as discussed later. Finally, unlike the other equations, the conservation equations are uniformly valid for all models. These equations are summarized below and not really discussed further. 

There is now a great interest in developing different kinds of fuel cells with several applications (in addition to the first and most developed application in space programs) depending on their nominal power stationary electric power plants (lOOkW-lOMW), power train sources (20-200kW) for the electrical vehicle (bus, truck and individual car), electricity and heat co-generation for buildings and houses (5-20 kW), auxiliary power units (1-100 kW) for different uses (automobiles, aircraft, space launchers, space stations, uninterruptible power supply, remote power, etc.) and portable electronic devices (1-100 W), for example, cell phones, computers, camcorders [2, 3]. 

The PEMFC is nowadays the most advanced low-temperature fuel cell technology [19, 20], because it can be used in several applications (space programs, electric vehicles, stationary power plants, auxiliary power units, portable electronics). The progress made in one application is greatly beneficial to the others. 

A conceptual design and selection of an ATR biodiesel processor for a vehicle fuel cell auxiliary power unit were reported by Specchia et al. [81]. Three processor options were compared for H2 production with respect to efficiency, complexity, compactness, safety, controllability and emissions. The ATR with both high-temperature shift (HTS) and low-temperature shift (LTS) reactors showed the most promising results. 

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