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The Effect of Microporous Layer in Phosphoric Acid Doped Polybenzimidazole Polymer Electrolyte Membrane Fuel Cell

A polybenzimidazole (PBI) based polymer electrolyte fuel cells, which called high temperature polymer electrolyte fuel cells (HT-PEMS), operate at higher temperatures (120-200°C) than conventional PEM fuel cells. Although it is known that HT-PEMS have some of the significant advantages as non-humidification requirements for membrane and the lack of liquid water at high temperature in the fuel cell, the generated water as a result of oxygen reduction reaction causes in the degradation of these systems. The generated water absorbed into membrane side interacts with the hydrophilic PBI matrix and it can cause swelling of membrane, so water transport mechanism in a Membrane Electrode Assembly (MEA) needs to be well understood and water balance must be calculated in MEA. Therefore, the water diffusion transport across the electrolyte should be determined. In this study, it is investigated firstly the water content in a MEA in the case of with/without Microporous Layer (MPL). Secondly, in the case of with MPL the effect of microporous layer’s thickness on the water management in fuel cell is investigated. For this aim, two-dimensional fuel cell with interdigitated flow-field is modeled using Comsol Multiphysics 4.2a software. The operating temperature and doping level is selected as 180°C and 6.75 RPU H3PO4/PBI, respectively. The results of this work brought out that MPL significantly effects to water content in MEA and reduces H2O concentration in MEA. Thus it can be prevented to flooding in MEA and so durability of the cell is increased.

Energy and Exergy Analysis of a Solid-Oxide Fuel Cell Power Generation System for an Aerial Vehicle (ISSA- 2015–139)

ABSTRACT This paper presents the performance of the solid-oxide fuel cell/gas turbine hybrid power generation system with heat recovery waste unit based on the energy and exergy analyses. The effect of air inlet temperature and air/fuel ratio on exergy destruction and network output is determined. For the numerical calculations, air inlet temperature and air fuel ratio are increased from 273 to 373 K and from 40 to 60, respectively. The results of the numerical calculations bring out that total exergy destruction quantity increases with the increase of air inlet temperature and air/fuel ratio. Furthermore, the maximum system overall first and second law efficiencies are obtained in the cases of air inlet temperature and air/fuel ratio equal to 273 K and 60, respectively, and these values are 62.09% and 54.91%.

Time-Dependent Neutronic Analysis of a Power-Flattened Gas Cooled Accelerator Driven System Fuelled with Thorium, Uranium, Plutonium, and Curium Dioxides TRISO Particles

This study presents the power flattening and time-dependent neutronic analysis of a conceptual helium gas cooled Accelerator Driven System (ADS) loaded with TRISO (tristructural-isotropic) fuel particles. Target material is lead-bismuth eutectic (LBE). ThO2, UO2, PuO2, and CmO2 TRISO particles are used as fuel. PuO2 and CmO2 fuels are extracted from PWR-MOX spent fuel. Subcritical core is radially divided into 10 equidistant subzones in order to flatten the power produced in the core. Tens of thousands of these TRISO fuel particles are embedded in the carbon matrix fuel pebbles as five different cases. The high-energy Monte Carlo code MCNPX 2.7 with the LA150 library is used for the neutronic calculations. Time-dependent burnup calculations are carried out for thermal fission power () of 1000 MW using the BURN card. The energy gain of the ADS is in the range of 99.98–148.64 at the beginning of a cycle. Furthermore, the peak-to-average fission power density ratio is obtained between 1.021 and 1.029 at the beginning of the cycle. These ratios show a good quasi-uniform power density for each case. Furthermore, up to 155.1 g 233U and 103.6 g 239Pu per day can be produced. The considered system has a high neutronic capability in terms of energy multiplication, fissile breeding, and spent fuel transmutation with thorium utilization.

Numerically Modeling of Anode Supported Tubular SOFC

Numerical models of Solid Oxide Fuel Cells (SOFCs) are important tools in understanding and investigate the effect of design and operation parameters of the SOFC performance and SOFC development works. In this study, one of the clean and highly efficient energy production systems, single tubular anode-supported SOFC is modeled numerically. Mathematical model of the single tubular SOFC is given in terms of the incompressible Navier- Stokes, Knudsen diffusion models, Butler–Volmer kinetic equations and Brinkman equations. For two-dimensional axisymmetric geometry, operating conditions, parameters of fuel cell and governing equations are solved by finite element method software ComsolMultiphysics. Pure H2 89% and H2O 11% are used at anode and air is used at the cathode side as reactant gasses. Temperature, pressure, porosity, permeability and especially distance of current collectors to the cell reactant gas inlet are studied. Optimal cell parameters for this model are determined and reasons of cell performance effects are explained.

Hydrogen Production Potential and Cost of Wind-Hydrogen Hybrid Energy System

Main aim of this study is to investigate annual wind power output, annual hydrogen production quantity and hydrogen production cost of wind-hydrogen energy system in the Pinarbasi-Kayseri region in Turkey which has remarkable wind potential in the central region of Turkey. Turkish State Meteorological Service (TSMS) measured the value of mean wind speed of Pinarbasi as 3.67 m/s above 10m ground between 2000 and 2006 years. In this study, three different hub heights (50m, 80m and 100m) were considered, and so the measured mean wind speed at 10m was extrapolated to considered heights and annual wind power output was calculated. Four different turbine rated powers (800kW, 900kW, 2000kW and 3000 kW) and two different electrolyser powers (120kW and 40kW) for hydrogen production were assumed. Levelised cost of electricity method was used in order to determine the cost analysis of wind energy and hydrogen production. The results of this study bring out clearly the variation of potential of hydrogen production and cost with wind speed, wind turbine hub height and wind turbine rated power and electrolyser power.Copyright