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In this paper, fuel composition and efficiency of solid oxide fuel cell with different methanol pretreating technologies are investigated. High concentrations of H2 and CO can be produced by methanol pretreatment at high temperature, whereas high concentration of methane can be produced at low temperature under the thermodynamic equilibrium condition. For steam reforming of methanol, high cell efficiency can be obtained, whereas for partial oxidation of methanol, the cell efficiency decreases most obviously compared with other pretreating technologies with the increase of O/C ratio. When the O/C ratio is 1.5, the cell efficiencies are 55.89% for steam reforming of methanol, 50.83% for autothermal reforming of methanol, and 45.77% for partial oxidation of methanol at 80% equivalent fuel utilization and 1073 K. When the O/C ratio increases to 2.5, the cell efficiency decreases slowly to 52.01% for steam reforming of methanol, whereas rapidly to 21.68% for partial oxidation of methanol at 80% equivalent fuel utilization and 1073 K. According to the calculated results under the thermodynamic equilibrium condition, suitable pretreating technology and O/C ratio for methanol pretreatment can be selected for the operation of solid oxide fuel cell, which can lead to the high efficiency and good stability of solid oxide fuel cell. [ABSTRACT FROM AUTHOR]

In this paper, ultrahigh fuel utilization (>98%) in polymer electrolyte fuel cells (PEFCs) is numerically studied to investigate three aspects for this operation strategy: its effect on fuel cell performance, occurance of fuel starvation, and altered water management. Simulation results reveal that the anode flow, when using pure hydrogen fuel, decelerates to nearly zero under the high fuel utlization. The anode gas flow remains high in the hydrogen concentration throughout the gas flow channel, eliminating concerns of fuel starvation and increased anode overpotential. The numerical study confirms the experimental observation that the high-fuel-utilization strategy has very little impact on cell power output in the stable operating regime. It is shown that fuel cell's water removal almost totally relies on the cathode channel flow under ultrahigh fuel utilization, which may be one cause for experimentally observed instability in fuel cell operation under low current density. [ABSTRACT FROM AUTHOR]

In this study, a high fuel utilization approach for polymer electrolyte fuel cells (PEFC) is proposed and studied experimentally. This approach uses an ultra-low hydrogen stoichiometry supply (i.e., ξa = 1.02) meanwhile sustaining stable cell performance. Systematic experiments showed the feasibility of high fuel utilization approach under different pressures and hydrogen/air inlet humidification conditions. It is indicated that the fuel cell is able to provide stable performance at a real fuel stoichiometry ξa = 1.02 under high-current density operation. For all the tests at ξa/ξc = 1.5/2.0 or 1.02/2.0, there exist unstable operation regimes typically in low power conditions. The instability as a result of flooding is affected mainly by air stoichiometry and less by fuel stoichiometry. [ABSTRACT FROM AUTHOR]

The present research work investigates the effect of orange peel oil on the ternary blend of diesel–biodiesel of waste cooking oil and n-butanol. The waste cooking oil methyl ester(WCOME) is produced by the transesterification process followed by one-step esterification. Four blends with varying orange peel oil concentrations (3%–21% v/v) with a fixed concentration (5%v/v) of WCOME were used in the present work. Evaluation of physicochemical properties provides sufficient validation for the utilization of fuel blends in a single-cylinder four-stroke air-cooled diesel engine. All the investigations are as per the standard of ASTM. The results show that the addition of orange peel has better results for the brake thermal efficiency and brake-specific energy consumption (BSEC) characteristics of the diesel engine. In comparison to neat diesel, the highest brake thermal efficiency is 22.49%, for the blend has a 21% (v/v) concentration of orange peel oil, while the BSEC is 18.44% for the same blend. The hydrocarbon and carbon monoxide emission was observed to be lowest for O21B15, while 0.46% nitrogen oxide reduction was observed in the same blend as compared to neat diesel. [ABSTRACT FROM AUTHOR]

The photovoltaic/thermal (PV/T) system can be integrated with other energy resources and, the optimal design of such integrated PV/T systems becomes important. Also, fuel cell with hydrogen consumption is significantly useful in combination with other renewable energy systems. The objective of this study is to investigate the effects of PV/T and fuel cell as a combined heat and power system on optimal design problem with considerations for PV/T unreliability. The contributions of this study are consideration unreliability of PV/T panels output heat and power and investigation the effects of PV/T and fuel cell on optimal design problem are investigated. Some limitations such as battery size, PV/T installation area, and demand unreliability are subjected to problem. As heuristic algorithm is applied in optimal design problem, it is shown that utilization of PV/T reduces cost by 1.10%. Also, with utilization of fuel cell beside other units, total cost is reduced as compared with literature. A critical sensitivity analysis is done and, it is concluded that several factors, namely, PV/T, energy storage system, conventional distributed generation, fuel cell, fuel prices, and power and heat profiles have considerable effects on optimal design. Among them, battery and fuel cell prices have the most and least effects. [ABSTRACT FROM AUTHOR]