Fuel Cell Systems as Power Sources for Sensor Applications

2013 ◽  
Vol 10 (4) ◽  
Author(s):  
Tony M. Thampan ◽  
Mark A. Govoni ◽  
John T. Clark
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Hybrid System ◽  
Operation Time ◽  
System Size ◽  
Power Sources ◽  
Sensor Applications ◽  
Load Following ◽  
Solar Battery ◽  
Direct Methanol

The increasing use of unattended sensors by the Information, Surveillance, and Reconnaissance community requires the development of higher power and energy density sources to provide increased capabilities and operation time while minimizing size and weight. Among the emerging power sources, fuel cell (FC) systems potentially offer an improved alternative to existing solutions. The Communications and Electronics Research and Development and Engineering Center/Command, Power & Integration Directorate/Army Power Division's Power Sources branch has been evaluating fuel cells to meet tactical power military applications. Testing of methanol based FC systems indicates 50% weight savings over a secondary Li-ion rechargeable system at 200 W h, and 30% weight savings over a primary Li battery at 600 W h. However, significant technical barriers to fuel cell based power sources for sensor deployment exist, including requirements for additional size and weight reduction to meet portable sensor design requirements. Additionally, testing of FC systems demonstrate the importance of appropriate battery hybridization to maintain load following as well as increasing system power density. A comparison of a Reformed Methanol FC system and a Direct Methanol FC system was also completed, and results for the system size, weight, and fuel consumption are similar for both technologies. To examine the benefits of larger power fuel cells appropriate for stationary unattended sensor use, a comparison of power and weight available from a solar/battery hybrid system versus a solar/battery/RMFC hybrid system was also completed. Although the solar/battery hybrid system's size and weight are larger than the hybrid system with an FC unit, 14 kg versus 8 kg, respectively, there is significant logistic burden when utilizing a FC system due to its methanol refueling requirement.

Techno-Economic Analysis and Feasibility Study of a Solid Oxide Fuel Cell-Battery Hybrid System for Water Taxi Application

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Datong Song ◽  
Xinge Zhang ◽  
Roberto Neagu ◽  
Wei Qu
Keyword(s):  
Fuel Cell ◽  
Economic Analysis ◽  
Solid Oxide Fuel Cell ◽  
Feasibility Study ◽  
Hybrid System ◽  
Ghg Emissions ◽  
Operation Time ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Power Sources

A hybrid power system consisting of an intermediate temperature solid oxide fuel cell (SOFC) and a lithium-ion battery is conceptually designed for water taxi applications. The sizing method of such a hybrid system is developed based on the resistance, acceleration performance, cruising cycle, and the speeds of a water taxi under the conditions of daily operation time and charge neutrality over a 24 h period. A techno-economic analysis (TEA) is performed for the proposed hybrid system and compared with other two power sources, a typical internal combustion engine (ICE), and a battery-only system. A feasibility study based on the weight and the volume of the hybrid system is conducted. The potential reduction of greenhouse gases (GHG) emissions is calculated and compared with the GHG emissions from water taxies powered by an ICE and a battery-only, respectively.

Fuel Cells vs. Competing Technologies

2003 ◽  
Author(s):  
Supramanian Srinivasan ◽  
Lakshmi Krishnan ◽  
Andrew B. Bocarsly ◽  
Kan-Lin Hsueh ◽  
Chiou-Chu Lai ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Direct Methanol Fuel Cells ◽  
Cell Structure ◽  
Proton Exchange ◽  
Point Of View ◽  
Direct Methanol ◽  
Energy Conversion Systems ◽  
Competing Technologies

Investments of over $1 B have been made for Fuel Cell R&D over the past five decades, for space and terrestrial applications; the latter includes military, residential power and heating, transportation and remote and portable power. The types of fuel cells investigated for these applications are PEMFCs (proton exchange membrane fuel cells), AFCs (alkaline fuel cells), DMFCs (direct methanol fuel cells), PAFCs (phosphoric acid fuel cells), MCFCs (molten carbon fuel cells), SOFCs (solid oxide fuel cells). Cell structure, operating principles, and characteristics of each type of fuel cell is briefly compared. The performances of fuel cells vs. competing technologies are analyzed. The key issues are which of these energy conversion systems are technologically advanced and economically favorable and can meet the lifetime, reliability and safety requirements. This paper reviews fuel cells vs. competing technologies in each application category from a scientific and engineering point of view.

Fuel-Cell Hybrid Systems to Generate Shipboard Electrical Power

2009 ◽  
Author(s):  
W. J. Sembler ◽  
S. Kumar
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Air Quality ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Cell Hybrid ◽  
Electrical Power ◽  
History Of ◽  
Marine Applications ◽  
Fuel Cell Hybrid

The reduction of shipboard airborne emissions has been receiving increased attention due to the desire to improve air quality and reduce the generation of greenhouse gases. The use of a fuel cell could represent an environmentally friendly way for a ship to generate in-port electrical power that would eliminate the need to operate diesel-driven generators or use shore power. This paper includes a brief description of the various types of fuel cells in use today, together with a review of the history of fuel cells in marine applications. In addition, the results of a feasibility study conducted to evaluate the use of a fuel-cell hybrid system to produce shipboard electrical power are presented.

Air Flow Real-time Optimization Strategy for Fuel Cell Hybrid Power Sources with Fuel Flow Based on Load-following

Fuel Cells ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 809-823 ◽  
Author(s):  
N. Bizon ◽  
G. Iana ◽  
E. Kurt ◽  
P. Thounthong ◽  
M. Oproescu ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Cell Hybrid ◽  
Optimization Strategy ◽  
Power Sources ◽  
Hybrid Power ◽  
Load Following ◽  
Fuel Flow ◽  
Time Optimization ◽  
Real Time Optimization

Design and Off-Design Analysis of a MW Hybrid System Based on Rolls-Royce Integrated Planar Solid Oxide Fuel Cells

2007 ◽  
Vol 129 (3) ◽  
pp. 792-797 ◽  
Author(s):  
Loredana Magistri ◽  
Michele Bozzolo ◽  
Olivier Tarnowski ◽  
Gerry Agnew ◽  
Aristide F. Massardo
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Hybrid System ◽  
System Size ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Ambient Conditions ◽  
Detailed Model ◽  
Design Point ◽  
Turbine Speed

In this paper the design point definition of a pressurised hybrid system based on the Rolls-Royce Integrated Planar-Solid Oxide Fuel Cells (IP-SOFCs) is presented and discussed. The hybrid system size is about 2 MWe and the design point analysis has been carried out using two different IP-SOFC models developed by Thermochemical Power Group (TPG) at the University of Genoa: (i) a generic one, where the transport and balance equations of the mass, energy and electrical charges are solved in a lumped volume at constant temperature; (ii) a detailed model where all the equations are solved in a finite difference approach inside the single cell. The first model has been used to define the hybrid system lay out and the characteristics of the main devices of the plant such as the recuperator, the compressor, the expander, etc. The second model has been used to verify the design point defined in the previous step, taking into account that the stack internal temperature behavior are now available and must be carefully considered. Apt modifications of the preliminary design point have been suggested using the detailed IP-SOFC system to obtain a feasible solution. In the second part of the paper some off-design performance of the Hybrid System carried out using detailed SOFC model are presented and discussed. In particular the influence of ambient conditions is shown, together with the possible part load operations at fixed and variable gas turbine speed. Some considerations on the compressor surge margin modification are reported.

Modeling of Coupled Mechanical and Chemical Degradation of the Ionomer Membrane in Polymer Electrolyte Fuel Cells

2018 ◽  
Vol MA2018-01 (32) ◽  
pp. 1992-1992
Author(s):  
Mohamed El Hannach ◽  
Ka Hung Wong ◽  
Yadvinder Singh ◽  
Narinder Singh Khattra ◽  
Erik Kjeang
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Operating Conditions ◽  
Chemical Degradation ◽  
Mechanical Degradation ◽  
Oh Radicals ◽  
List Type ◽  
Hydrogen Fuel Cell ◽  
Hydrogen Fuel ◽  
Power Sources

The hydrogen fuel cell is a promising technology that supports the development of sustainable energy systems and zero emission vehicles. One of the key technical challenges for the use of fuel cells in the transportation sector is the high durability requirements 1–3. One of the key components that control the overall life time of a hydrogen fuel cell is the ionomer membrane that conducts the protons and allows the separation between the anode and the cathode. During fuel cell operation, the membrane is subjected to two categories of degradation: mechanical and chemical. These degradations lead to reduction in the performance, crossover of reactants between anode and cathode and ultimately total failure of the fuel cell. The mechanical degradation occurs when the membrane swells and shrinks under the variation of the local hydration level. This leads to fatigue of the ionomer structure and ultimately irreversible damage. However, under pure mechanical degradation the damage takes a very long time to occur 4,5. Sadeghi et al. 5 observed failure of the membrane after 20,000 of accelerated mechanical stress testing. This translates into a longer lifetime in comparison to what is observed in field operation 6. The chemical degradation on the other hand is caused by the presence of harmful chemicals such as OH radicals that attack the side chains and the main chains of the ionomer 7,8. Such attacks weaken the structural integrity of the membrane and make it prone to severe mechanical damage. Hence understanding the effect of combining both categories of membrane degradation is the key to accurate prediction of the time to failure of the fuel cell. In this work we propose a novel model that represents accurately the structural properties of the membrane and couples the chemical and the mechanical degradations to estimate when the ultimate failure is initiated. The model is based on a network of agglomerated fibrils corresponding to the basic building block of the membrane structure 9–11. The mechanical and chemical properties are defined for each fibril and probability functions are used to evaluate the likelihood of a fibril to break under certain operating conditions. The description of the fundamentals behind the approach will be presented. Two set of simulations will be presented and discussed. The first one corresponding to standard testing scenarios that were used to validate the model. The second set of results will highlight the impact of coupling both degradation mechanisms on the estimation of the failure initiation time. The main strengths of the model and the future development will be discussed as well. T. Sinigaglia, F. Lewiski, M. E. Santos Martins, and J. C. Mairesse Siluk, Int. J. Hydrogen Energy, 42, 24597–24611 (2017). T. Jahnke et al., J. Power Sources, 304, 207–233 (2016). P. Ahmadi and E. Kjeang, Int. J. Energy Res., 714–727 (2016). X. Huang et al., J. Polym. Sci. Part B Polym. Phys., 44, 2346–2357 (2006). A. Sadeghi Alavijeh et al., J. Electrochem. Soc., 162, F1461–F1469 (2015). N. Macauley et al., J. Power Sources, 336, 240–250 (2016). K. H. Wong and E. Kjeang, J. Electrochem. Soc., 161, F823–F832 (2014). K. H. Wong and E. Kjeang, ChemSusChem, 8, 1072–1082 (2015). P.-É. A. Melchy and M. H. Eikerling, J. Phys. Condens. Matter, 27, 325103–6 (2015). J. A. Elliott et al., Soft Matter, 7, 6820 (2011). L. Rubatat, G. Gebel, and O. Diat, Macromolecules, 37, 7772–7783 (2004).

Development of a 600 W Proton Exchange Membrane Fuel Cell Power System for the Hazardous Mission Robot

2010 ◽  
Vol 7 (3) ◽  
Author(s):  
Sang-Yeop Lee ◽  
In-Gyu Min ◽  
Hyoung-Juhn Kim ◽  
Suk Woo Nam ◽  
Jaeyoung Lee ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Power System ◽  
Power Density ◽  
Proton Exchange Membrane ◽  
Hybrid Control ◽  
Operation Time ◽  
Proton Exchange ◽  
Power Sources ◽  
Start Up ◽  
Exchange Membrane

Due to the advantage of fuel cells over secondary batteries such as long operation time, many efforts were executed in order to use fuel cells as main power sources of small electronic devices such as laptop computers and mobile phones. For the same reason, fuel cells are promising power sources for the hazardous mission robots. Fuel cells are able to increase their radius action through extension of operation time. Despite this advantage, there still exist technical barriers such as increasing power density, efficient hydrogen storage, and fast startup of the power system. First, in order to increase power density, the united stack including proton exchange membrane fuel cells (PEMFC) and membrane humidifying cells were developed. Also, the hydrogen generating system using NaBH4 solution was employed to store hydrogen effectively. In addition, to shorten start-up time, hybrid control of PEMFC and Li-ion battery was adopted. The approaches mentioned above were evaluated. The developed PEMFC/humidifier stack showed high performance. As compared with full humidification condition by external humidifiers, the performance decrease was only 1% even though hydrogen was not humidified and air was partially humidified. Besides, by integrating the PEMFC and the humidifier into a single stack, considerable space for tubing between them was saved. Also, the hydrogen generator operated well with the PEMFC system and allowed for effective fuel storing and refueling. In addition, due to the efficient hybrid control of PEMFC and battery, start-up time was significantly shortened and capacity of PEMFC was reduced, resulting in compactness of the power system. In conclusion, a 600 W PEMFC power system was developed and successfully operated with the robot. Through development and evaluation of the PEMFC power system, the possibility of PEMFC as a novel power source for the hazardous mission robot was verified.

Performance Comparison of Internal Reforming Against External Reforming in a Solid Oxide Fuel Cell, Gas Turbine Hybrid System

2005 ◽  
Vol 127 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Eric A. Liese ◽  
Randall S. Gemmen
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Hybrid System ◽  
Waste Heat ◽  
Performance Comparison ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Internal Reforming ◽  
Hybrid Configuration

Solid Oxide Fuel Cell (SOFC) developers are presently considering both internal and external reforming fuel cell designs. Generally, the endothermic reforming reaction and excess air through the cathode provide the cooling needed to remove waste heat from the fuel cell. Current information suggests that external reforming fuel cells will require a flow rate twice the amount necessary for internal reforming fuel cells. The increased airflow could negatively impact system performance. This paper compares the performance among various external reforming hybrid configurations and an internal reforming hybrid configuration. A system configuration that uses the reformer to cool a cathode recycle stream is introduced, and a system that uses interstage external reforming is proposed. Results show that the thermodynamic performance of these proposed concepts are an improvement over a base-concept external approach, and can be better than an internal reforming hybrid system, depending on the fuel cell cooling requirements.

Improved Methanol Oxidation Activity Through Oxidation-Induced Phase Separation of PtRu Electrocatalysts

2000 ◽  
Vol 6 (S2) ◽  
pp. 24-25
Author(s):  
R.M. Stroud ◽  
J.W. Long ◽  
K.E. Swider ◽  
D.R. Rolison
Keyword(s):  
Fuel Cells ◽  
Methanol Oxidation ◽  
Direct Methanol Fuel Cells ◽  
Ruthenium Oxide ◽  
Hydrogen Fuel ◽  
Oxidation Activity ◽  
Power Sources ◽  
Bimetallic Alloys ◽  
Point Of Use ◽  
Direct Methanol

Direct methanol fuel cells (DMFCs) offer a simpler, safer technology for point-of-use power sources compared to other hydrogen fuel cells, by avoiding the need to store hydrogen fuel or to carry out the reformation of hydrocarbons. The direct methanol oxidation electrocatalyst of choice is a nanoscale black consisting of a 50:50 atom % mixture of Pt and Ru. It has recently become known that these presumed bimetallic alloys in fact contain an array of metal, oxide and hydrous phases, which are easily misidentified in routine x-ray diffraction measurements due to particle size-broadening and poor crystallinity. By combining transmission electron microscopy, electrochemistry and thermogravimetric studies, we demonstrate here that the route to improved catalytic activity is not by phase purification of the bimetallic alloys, but instead phase engineering of hydrous ruthenium oxide and Pt mixtures.

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