Application of a decomposition strategy to the optimal synthesis/design of a fuel cell sub-system
Abstract
The application of a decomposition methodology to the synthesis/design
optimization of a stationary cogeneration fuel cell sub-system for residential/commercial
applications is the focus of this work. To accomplish this, a number of different
configurations for the fuel cell sub-system are presented and discussed. The most
promising candidate configuration, which combines features of different configurations
found in the literature, is chosen for detailed thermodynamic, geometric, and economic
modeling both at design and off-design. The case is then made for the usefulness and
need of decomposition in large-scale optimization. The types of decomposition strategies
considered are time and physical decomposition. Specific solution approaches to the
latter, namely Local-Global Optimization (LGO) and Iterative Local-Global Optimization
(ILGO) are outlined in the thesis. Time decomposition and physical decomposition using
the LGO approach are applied to the fuel cell sub-system. These techniques prove to be
useful tools for simplifying the overall synthesis/design optimization problem of the fuel
cell sub-system.
Finally, the results of the decomposed synthesis/design optimization of the fuel cell subsystem
indicate that this sub-system is more economical for a relatively large cluster of
residences (i.e. 50). To achieve a unit cost of power production of less than 10 cents/kWh
on an exergy basis requires the manufacture of more than 1500 fuel cell sub-system units
per year. In addition, based on the off-design optimization results, the fuel cell subsystem
is unable by itself to satisfy the winter heat demands. Thus, the case is made for
integrating the fuel cell sub-system with another sub-system, namely, a heat pump.
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- Masters Theses [18654]