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Applications Analysis: Increasing the Efficiency of a Reformer for a PEM Fuel Cell
Flow chart
Proposition:
A manufacturer of component systems for fuel cells is currently employing a refractory ceramic fiber based blanket insulation (2 layers of 1” thick, 8# density) in a series of reformers that they manufacture for commercial PEM fuel cells. The reformer units are approximately 48” tall, have a diameter (outer) of 8”, and operate at 650°F. In an effort to make their reformer systems as efficient as possible, with the highest return on investment to their consumers, the company is looking at replacing their current insulation lining with microporous materials.
Primary Goals:
Minimize the amount of heat lost through the insulation lining of the reformer.
Decrease the cold face temperature of the reformer.
Secondary Goals:
Either reduce the cost of the insulation itself, or provide a greater return on investment for the system based on energy savings.
Proposal:
Simply replacing the current material in use (i.e. Ceramic Fiber Blanket 1” 8#) with the same thickness of DynaGuard Flexible 16# will reduce the energy consumption and subsequent heat loss of the reformer by as much as 50%, while simultaneously reducing the cold face temperature by 15% and providing suitable return on investment financially.
Thermal Analysis & Comparison:
Thermo Analysis and Comparison chart
Results:
• The DynaGuard Flexible 16# material allows approximately 50% less heat to escape through the lining of the insulation material and thusly improves its overall efficiency in reducing the amount of energy necessary to keep the reformer at the desired temperature.
• The DynaGuard Flexible 16# material yields a cold face temperature 20° lower (approx 15%) than that of the current lining using Ceramic Fiber Blanket.
• The heat loss requirement of no greater than 249.71 Btu/Ft2/Hr is met by the DynaGuard Ladle Liner 16# material, and is actually an improvement over the composite with Ceramic Fiber Paper (247.05 Btu/Ft2/Hr vs. 249.71 Btu/Ft2/Hr), yielding a greater degree of heat containment in the ladle and a minimization of heat loss through the composite.
Financial Analysis & Comparison:
Given the differences in heat loss (Btu/Sf/Hr) for the three materials, the following can be estimated for the amount of heat lost through the system in $/year for each:
Financial Analysis and Comparison
Results
• The DynaGuarde Flexible 16# material saves $8.13/year over the Ceramic Fiber Blanket material, which is enough by itself to pay for the initial cost of material, and adds greater financial savings over the estimated life of the reformer.
Conclusion:
The DynaGuard Flexible 16# material is the best material to accomplish all the objectives that the company set forth as their primary and secondary goals. It utilizes the least amount of material for the greatest thermal management and financial gains, and performs at the given temperature levels almost twice as efficiently as the other materials proposed.
For more information about how ThermoDyne’s DynaGuardeFlexible, Ladle Liner, Board or Panel materials may be of use in your particular application, please contact ThermoDyne’s team of Application Engineers at toll-free: 866.741.5458.
Assumptions:
- 1 KwHr = 3413 Btu
• $.065/KwHr = estimated average for energy costs. This figure may vary with facility location and amount of energy used.
- Calculations assume ambient air temperature to be = 80_F, with natural convection consistent with an indoor environment.
- Calculations and information provided are for comparison purposes only, and are not intended for design specifications as individual scenarios for material use may vary.
- Total square footage of reformer is 1.36 SF.
• Graphic courtesy of Fuel Cells.org.
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