Overview

• Science and Engineering Building (SEB)

• SOFC Basics

• Diffusion Flux Model

• SOFC Design

– Tubular SOFC Design by Siemens-Westinghouse

– Balance of Plant (BOP) Components

• Results

• Conclusion

Science and Engineering Building (SEB)

SOFC Basics

Cathode

SOFC Basics

SOFC Advantages

• Fuel Flexibility

• Nonprecious metal catalyst

• High-quality waste heat for cogeneration applications

• Solid Electrolyte

• Relatively high power density

Diffusion Flux Model

Diffusion Flux Model

Species

Mole Fraction

Diffusion Flux Model

Species

Mole Fraction

Diffusion Flux Model

• Increasing the hydrogen stoichiometric factor was found to have minimal effect on the overall performance of the system while only decreasing the fuel efficiency.

• The oxygen stoichiometric factor played a larger role, with diminishing returns as the value was increased.

SOFC Design: BOP Components - Inverter

• In order to meet the ~2600 kVA design of the SEB, a power inverter was necessary.

• From the technical sheets, we found that the AAB Compact Skid PVS980-CS-US was adequate, providing up to 4000 kVA power output through a dual inverter system.

• The power input to this inverter setup is 6400 kW with a maximum input voltage of 1,500 V.

• The fuel cell system is designed to provide the inverter system with its maximum possible input when operating at 90% of the limiting current density.

Tubular SOFC Design by Siemens-Westinghouse

• A tubular fuel cell design is implemented

• The dimensions of each cell are provided in the table below:

SOFC Design

SOFC Design: BOP Components -

Blower

Results

• To design the stack, an operation temperature of 925 K was chosen with hydrogen

and oxygen stoichiometric factors of 1.25 and 3, respectively. The pumps operate

at 500 LPM flow rate.

• For these conditions, the model gives the following stack results:

• Under the operational load of 2,600 kVA for this same stack we get:

Results

• The design and operation point of the fuel cell stack can be plotted over the j-V

and power curves to better illustrate the results.