Neal Rosenthal - Academia.edu (original) (raw)

Papers by Neal Rosenthal

Active" Direct Methanol Fuel Cells (DMFC) must rely on equipment to run whereas passive DMFCs can... more Active" Direct Methanol Fuel Cells (DMFC) must rely on equipment to run whereas passive DMFCs can run in ambient conditions without any equipment, allowing for potential use in portable devices. In this report, a passive DMFC was designed and constructed with the potential of being equivalent to a battery then compared to an active DMFC and a battery. Passive DMFCs, while not as good performance-wise as active DMFCs, perform notably better than a battery as an energy source.

While Direct Methanol Fuel Cells (DMFC) have a promising future as a long-lasting and environment... more While Direct Methanol Fuel Cells (DMFC) have a promising future as a long-lasting and environmentally friendly energy source, the use of balance of plant (BOP) equipment, such as pumps, fans, and compressors, create a complex system that can significantly reduce plant efficiency and increase cost. As an alternative, passive DMFCs have been designed and studied due to their ability to run under ambient conditions without any BOP equipment. However, before they become a feasible energy source, more must be understood about their promise and limitations. In this thesis, performance of a self-designed and constructed passive DMFC was investigated. In addition, an analytical mathematical model was developed in order to gain a better understanding of the limitations of the passive DMFC. The model was compared with literature's data to ensure reliability. Passive DMFCs, consisting of one to twelve Membrane Electrode Assemblies (MEAs) were designed, constructed and tested. The smaller scale fuel cell was optimized using different setups and elaborately tested using a variety of fuels, most notably methanol chafing gel, to determine an optimal performance curve. The larger fuel cells were further used to test for longterm performance and practical feasibility. The compact four-cell units could run for at least 24 hours and can provide performance akin to an AA battery. A larger 12-cell fuel cell was also designed and built to test feasibility as a convenient power supply for camping equipment and other portable electronics, and was tested with neat methanol and methanol gel. In all fuel cell prototypes, polarization plots were obtained, along with open circuit voltage (OCV) plots and long-term performance plots. While it is currently not possible to differentiate which methanol fuel source is the best option without a more thorough investigation, methanol gel has shown great potential as a readily available commercial fuel.

Passive Direct Methanol Fuel Cells (PDMFCs) are a potentially attractive power source for portabl... more Passive Direct Methanol Fuel Cells (PDMFCs) are a potentially attractive power source for portable applications, due to their high power density, easy fuel storage, and the ability to run at completely ambient conditions. However, design and development of a truly passive, air-breathing, orientation-independent, compact PDMFC fueled by neat methanol that can compete effectively with ever-improving batteries for low wattage portable power for consumer or military applications has proved to be challenging. Improved theoretical understanding of the fundamental transport and reaction processes within PDMFCs can help, which is the goal of this work. A relatively simple model is described resulting in analytical solutions that can provide important insights into the factors that limit PDMFC performance. The key factor limiting performance is the facile methanol crossover across the polymer electrolyte membrane (PEM), resulting in poor performance, energy density, and efficiency. In other ...

The direct methanol fuel cell (DMFC) has significant but rather unfulfilled promise because of it... more The direct methanol fuel cell (DMFC) has significant but rather unfulfilled promise because of its poor performance and low efficiency despite using dilute feeds, in large part because of the use of Nafion® membrane as the electrolyte. While this is well known, quantitative aspects of how the membrane transport characteristics affect the DMFC performance and efficiency are less well appreciated. We discuss a comprehensive analytical model that describes how the conductivity, water, methanol, and oxygen permeability of Nafion® membrane affects the DMFC performance and efficiency. A comparison of experiments and theory is provided. Thus, the model accurately predicts the effect of methanol crossover on open-circuit voltage (OCV) and on polarization of the fuel cell. It also correctly describes the effects of temperature and methanol feed concentration on DMFC performance. It describes the significant power losses because of electrode overpotentials and from methanol crossover, resulti...

Journal of Power Sources, 2012

The direct methanol fuel cell (DMFC) has a significant potential in consumer electronics and in b... more The direct methanol fuel cell (DMFC) has a significant potential in consumer electronics and in backup and portable power. Its progress is, however, hindered, in part, by a lack of an adequate fundamental understanding of the effect of various operating and design variables on its performance. While detailed computational models are available, an analytical model is attractive for ease of comprehension and ready utility. Therefore, we have developed a comprehensive yet tractable one-dimensional, isothermal, explicit analytical model based largely on a priori parameters, and in terms of quantities with tangible meaning. The model correctly predicts the extent of methanol crossover and its effect on open-circuit voltage (OCV) as well as on polarization of the anode, cathode, and the fuel cell. It also accurately describes the effects of methanol feed concentration and temperature on DMFC performance. It aptly predicts the significant power losses from the large anode and cathode overpotentials as well as from methanol crossover, and the resulting low DMFC efficiency, except over a narrow range of operating conditions. The insightful model can be used, e.g., in real-time control of DMFC to operate in the narrow region of high efficiency and power density.

The goal of this project was to compare possible risk factors associated with selected High Adven... more The goal of this project was to compare possible risk factors associated with selected High Adventure Recreational Activities and create possible risk mitigation strategies from these comparisons. Our research involved gathering information on risk management, injury statistics, and participant behavior trends. The final result was recommendations to CPSC about potential risk mitigation strategies and possible improvements to their methods of collecting and analyzing nationwide injury data.

Active" Direct Methanol Fuel Cells (DMFC) must rely on equipment to run whereas passive DMFCs can... more Active" Direct Methanol Fuel Cells (DMFC) must rely on equipment to run whereas passive DMFCs can run in ambient conditions without any equipment, allowing for potential use in portable devices. In this report, a passive DMFC was designed and constructed with the potential of being equivalent to a battery then compared to an active DMFC and a battery. Passive DMFCs, while not as good performance-wise as active DMFCs, perform notably better than a battery as an energy source.

While Direct Methanol Fuel Cells (DMFC) have a promising future as a long-lasting and environment... more While Direct Methanol Fuel Cells (DMFC) have a promising future as a long-lasting and environmentally friendly energy source, the use of balance of plant (BOP) equipment, such as pumps, fans, and compressors, create a complex system that can significantly reduce plant efficiency and increase cost. As an alternative, passive DMFCs have been designed and studied due to their ability to run under ambient conditions without any BOP equipment. However, before they become a feasible energy source, more must be understood about their promise and limitations. In this thesis, performance of a self-designed and constructed passive DMFC was investigated. In addition, an analytical mathematical model was developed in order to gain a better understanding of the limitations of the passive DMFC. The model was compared with literature's data to ensure reliability. Passive DMFCs, consisting of one to twelve Membrane Electrode Assemblies (MEAs) were designed, constructed and tested. The smaller scale fuel cell was optimized using different setups and elaborately tested using a variety of fuels, most notably methanol chafing gel, to determine an optimal performance curve. The larger fuel cells were further used to test for longterm performance and practical feasibility. The compact four-cell units could run for at least 24 hours and can provide performance akin to an AA battery. A larger 12-cell fuel cell was also designed and built to test feasibility as a convenient power supply for camping equipment and other portable electronics, and was tested with neat methanol and methanol gel. In all fuel cell prototypes, polarization plots were obtained, along with open circuit voltage (OCV) plots and long-term performance plots. While it is currently not possible to differentiate which methanol fuel source is the best option without a more thorough investigation, methanol gel has shown great potential as a readily available commercial fuel.

Passive Direct Methanol Fuel Cells (PDMFCs) are a potentially attractive power source for portabl... more Passive Direct Methanol Fuel Cells (PDMFCs) are a potentially attractive power source for portable applications, due to their high power density, easy fuel storage, and the ability to run at completely ambient conditions. However, design and development of a truly passive, air-breathing, orientation-independent, compact PDMFC fueled by neat methanol that can compete effectively with ever-improving batteries for low wattage portable power for consumer or military applications has proved to be challenging. Improved theoretical understanding of the fundamental transport and reaction processes within PDMFCs can help, which is the goal of this work. A relatively simple model is described resulting in analytical solutions that can provide important insights into the factors that limit PDMFC performance. The key factor limiting performance is the facile methanol crossover across the polymer electrolyte membrane (PEM), resulting in poor performance, energy density, and efficiency. In other ...

The direct methanol fuel cell (DMFC) has significant but rather unfulfilled promise because of it... more The direct methanol fuel cell (DMFC) has significant but rather unfulfilled promise because of its poor performance and low efficiency despite using dilute feeds, in large part because of the use of Nafion® membrane as the electrolyte. While this is well known, quantitative aspects of how the membrane transport characteristics affect the DMFC performance and efficiency are less well appreciated. We discuss a comprehensive analytical model that describes how the conductivity, water, methanol, and oxygen permeability of Nafion® membrane affects the DMFC performance and efficiency. A comparison of experiments and theory is provided. Thus, the model accurately predicts the effect of methanol crossover on open-circuit voltage (OCV) and on polarization of the fuel cell. It also correctly describes the effects of temperature and methanol feed concentration on DMFC performance. It describes the significant power losses because of electrode overpotentials and from methanol crossover, resulti...

Journal of Power Sources, 2012

The direct methanol fuel cell (DMFC) has a significant potential in consumer electronics and in b... more The direct methanol fuel cell (DMFC) has a significant potential in consumer electronics and in backup and portable power. Its progress is, however, hindered, in part, by a lack of an adequate fundamental understanding of the effect of various operating and design variables on its performance. While detailed computational models are available, an analytical model is attractive for ease of comprehension and ready utility. Therefore, we have developed a comprehensive yet tractable one-dimensional, isothermal, explicit analytical model based largely on a priori parameters, and in terms of quantities with tangible meaning. The model correctly predicts the extent of methanol crossover and its effect on open-circuit voltage (OCV) as well as on polarization of the anode, cathode, and the fuel cell. It also accurately describes the effects of methanol feed concentration and temperature on DMFC performance. It aptly predicts the significant power losses from the large anode and cathode overpotentials as well as from methanol crossover, and the resulting low DMFC efficiency, except over a narrow range of operating conditions. The insightful model can be used, e.g., in real-time control of DMFC to operate in the narrow region of high efficiency and power density.

The goal of this project was to compare possible risk factors associated with selected High Adven... more The goal of this project was to compare possible risk factors associated with selected High Adventure Recreational Activities and create possible risk mitigation strategies from these comparisons. Our research involved gathering information on risk management, injury statistics, and participant behavior trends. The final result was recommendations to CPSC about potential risk mitigation strategies and possible improvements to their methods of collecting and analyzing nationwide injury data.