Building-integrated fuel cells

The PEM fuel cell is the leading alternative for building-integrated applications, where multi-functionality would allow current natural gas burners to be replaced by combined heat-and-power systems, possibly with the additional option of supplying hydrogen to a one-vehicle filling station. One may think that if the automobile industry is successful in developing a viable 

PEM fuel cell for vehicles, then it will be directly applicable for stationary purposes. However, this is only partially true, as the service-life requirements are much higher for stationary uses. The aim at the current natural gas customers implies that a gas reformer needs to be integrated in the system. The customers that currently have access to piped natural gas is only a segment of the total market, with a share that varies between countries. 

Overall, the cost and technical performance of PEM fuel cells exhibit the same problems for decentralised stationary as for mobile applications, with the mentioned qualification that durability requirements are substantially higher. Both apphcations are in areas, where consumers in most parts of the world are accustomed to paying a fairly high energy price, as compared with that characterising central power plant operators. 

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Figure 4.13. Vision of building-integrated fuel cell system supplying heat, power and hydrogen as vehicle fuel. (From Honda (2004), used with permission.)...

At 1-10 W (watts), fuel cells could be used as battery replacements at 100 W to 1 kW, fuel cells could find military applications which require lightweight portable power sources for communications and weapon power at 1 - 10 kW, fuel cells could supply power to residential buildings and serve as auxiliary power units in vehicles and trucks. At higher power levels, the solid oxide fuel cell (SOFC) could be an effective approach for the distributed power generation and the cogeneration (i.e., combined heat and power). Above 1 MW, the SOFC could be integrated with a turbine power plant to improve the overall efficiency of power generation and reduce emissions. ... 

Figure 5.3. Layout of a decentralised, building-integrated hydrogen and fuel cell system based on intermittent primary power sources (such as wind or solar energy), reversible fuel cells and local stores, including stationary and maybe vehicle-based stores, and possibly capable of interchanging hydrogen with users in other buildings through pipelines (Sorensen, 2002a).

The building integration concept used in the decentralised scenario of section 5.5 is shown in Fig. 5.3. The concept is based on availability of reversible fuel cell technology, which as mentioned in Chapter 3, section 3.5.5 seems a realistic assumption, at least for a future scenario. At an increased cost, the reversible fuel cell could of course be replaced by a pair of a power-... 

To build an efficient, high-quality microscale fuel cell, microfabrication techniques need to be combined with appropriate materials such as Nation based membrane electrode assemblies (MEAs). These techniques must be able to produce three-dimensional structures, allow reactant and product flow into and out of the device, process appropriate materials, and should be of low cost. Fortimately, traditional thin film techniques can be modified for microscale fuel cell fabrication, while maintaining their advantages of surface preparation, sensor integration, and finishing or packaging. In addition, other techniques are also available and are discussed in the following sections. 

Design, build and demonstrate a fully integrated, 50-kilowatt electric (kWe) catalytic autothermal fuel processor system. The fuel processor will produce a hydrogen-rich gas for direct use in proton exchange membrane (PEM) fuel cell systems for vehicle applications. 

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