Comparison with Heat Engine

X. Li. Thermodynamic performance of fuel cells and comparison with heat engines. In T. S. Zhao, K. D. Kreuer, and T. Nguyen, editors, Advances in Fuel Cells, volume 1, pages 1-46, Elsevier, New York, 2007. 

The exergy equation (2.26) enables useful information on the irreversibilities and lost work to be obtained, in comparison with a Carnot cycle operating within the same temperature limits (T ,ax = Ey and T in = To). Note first that if the heat supplied is the same to each of the two cycles (Carnot and IJB), then the work output from the Carnot engine (Wcar) is greater than that of the IJB cycle (Wijg), and the heat rejected from the former is less than that rejected by the latter. 

Comparisons of heat-release rates and combustion photographs obtained in the HSCI engine (conventional) and Premixed Cl engine (MK). (From Kimura, S., Aoki, O., Kitahara, Y., and Aiyoshizawa, E., Ultra-Clean Combustion Technology Combining a Low-Temperature and Premixed Combustion Concept for Meeting Future Emissions Standards, SAE, 2001-01-0200,2001. With permission.)... 

For proper comparison with the efficiency of a heat engine, the efficiency of a fuel cell must be calculated on the basis of the heat content of the fuel (AHI2F = 1.48 VO, not on the basis of the free energy change (AGI2F = J.23 VO-... 

For quantitative validation of simulation results, it is often necessary to compare predicted profiles (of velocity or other variable of interest) with experimental data X-Y plotting facilities are useful for this purpose. Most post-processors allow the user to import tabulated data for comparison with simulation results. Facilities to calculate the usual global quantities of interest to reactor engineers, such as overall pressure drop, dispersed phase volume fraction, heat or mass transfer rates and so on, are necessary to address reactor engineering concerns. Most codes allow use of user-defined routines to evaluate different quantities of interest, which may then be displayed using the standard tools discussed above. 

Despite the potential of the BEM to reduce the dimensionahty of the numerical solution and provide a direct measure of the interfadal flux, it has been poorly exploited by workers in the electrochemical field in comparison with the FDM and the FEM. By comparison, heat and mass transfer have been widely treated using the BEM in the engineering literature [148-151]. In 1984, the BEM was employed to calculate the primary current distribution during an electropolymerization reaction [152], the potential of the BEM for apphcations to irregular geometries was also noted. Hume and coworkers [153] used the approach to analyze mass transport effects of electrode-position through polymeric masks. 

A.P. Colburn, "A Method of Correlating Forced Convection Heat Transfer Data and a Comparison with Fluid Friction," Transactions of the American Institute of Chemical Engineers, vol. 29, (1933), 174-210. 

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