Investigation of the performance of a direct borohydride fuel cell with low Pt/C catalyst loading under different operating conditions
Abstract
Fuel cells are promising alternative energy converters in terms of preventing pollution, efficiency, and noise. Direct borohydride fuel cells (DBFCs) which are defined as a sub-class of polymer electrolyte membrane fuel cells (PEMFCs) and direct liquid fuel cells (DLFC) have increased attention recently since they offer a solution for hydrogen storage problem. However, the commercialization of DBFC is hindered by the need of high platinum loadings. Therefore, reducing the platinum content is crucial to develop cost-effective DBFC without compromising performance. This research focuses on the effects of operational parameters on the DBFC performance with low level Pt/C catalyst loading (anode: 0.32 mg/cm2, cathode: 0.36 mg/cm2). The gas diffusion electrode was prepared by spray-coating technique. The peak power density of 19.95 mW/cm2 was obtained at 80 °C when 1 mL/min was used as a flow rate of fuel.
Investigation of the effects of SPEEK and its clay composite membranes on the performance of Direct Borohydride Fuel Cell
Abstract
In this study, composite cation exchange membranes (CEM) were developed. With the experience from widely studied proton exchange membrane fuel cells (PEMFC), sulfonated polyether ether ketone (SPEEK) was prepared to be a more effective and cheaper ionomer alternative to the industry standard Nafion ®. SPEEK polymer membrane can reach sufficient ionic conductivities but have some mechanical and chemical stability problems (at a high degree of sulfonations (DS)). Therefore, in order to optimize the membrane, composite mixing with a well-known organic/inorganic clays called Cloisite® 15A, Cloisite ® 30B and MMT were used. Test cells for both single-cell and conductivity were designed and constructed. The ionic conductivity cell was different than the ones used in most studies, measuring conductivity in-plane with 4 probes using EIS. The membranes were characterized for their proton conductivity with electrochemical impedance spectroscopy (EIS), for DS with H NMR, water uptake, and fuel cell performance tests. First results showed that the acidic sulfonic groups of SPEEK interacted with organic/inorganic clays and as a result of partial barrier the ionic conductivity was decreased but power densities were increased. SPEEK-Cloisite® 30B composite membrane has given 40 mW/cm2 power density value which is higher than pure SPEEK membrane (35 mW/cm2). The proton conductivities of the final composite membranes were close to bare SPEEK membranes which are 0,065 and 0,075 S/cm for SPEEK-Cloisite ® 30B and pristine SPEEK, respectively.
The statistical relationship between flow channel geometry and pressure drop in a direct methanol fuel cell with parallel channels
Abstract
In this study, the relationship between the pressure drop on the channels due to the methanol flow and the geometry of the flow channels on the anode side of a direct methanol fuel cell (DMFC) has been investigated. Parallel type channels are used as flow channels. The active area of the fuel cell is 5 × 5 cm2. The system consists of channels that are optimally placed in the active area, with channel widths and distance of the channels kept constant. Combinations of 1, 1.5, 2, 2.5, 3 mm measurements were used for flow channel width and distance between channels. The ratio of the area created by the prepared geometries to the active area (percentage of contact area) is defined as a new parameter. The main motivation of this study is to be able to determine the effect of the geometric measurements of the designed flow channels on the intra-channel pressure drop by statistical method. There was a statistically significant difference between the flow channel widths and the distance between the channels and the pressure. Among the selected parameters, the effect of the channel width on the pressure drop was highest but it had a statistically moderate relationship. However, there was no significant relationship between the distance between channels and the pressure drop.
Analysis of wind energy potential; A case study of Kocaeli University campus
Abstract
Determination of the wind energy potential is achieved by point measurement at the place. MERRA software which is generated by NASA provides the point data values. The point data with using Windographer software gives theoretically potential energy of wind turbines in a short time. In this study, the Kocaeli University campus selected a point, where the wind turbines are planned to be implemented. The obtained output power from wind energy will be examined. MERRA software and Windographer software are being used during this energy’s production study. The wind speed and direction analysis within 1 h of resolution is being performed at some points by using MERRA program. Windographer automatically defines wind resource data such as wind speed, standard deviation, vertical wind speed, direction, temperature, pressure, and relative humidity. Within the 4 point coordinates properly identified by the software, point “B” was selected. The annual wind data of the point “B” was analyzed and the annual amount of energy was calculated. In this study, GE 1.7-100 wind turbine was used. The generated energy and turbine output power were calculated by the Windographer program.
The effect of different gas diffusion layer porosity on proton exchange membrane fuel cells
Abstract
In this study, the effect of cathode side gas diffusion layers’ porosity on Proton Exchange Membrane Fuel Cells (PEMFC) was modelled. In the model prepared, all the geometric parameters and material characteristics were kept fixed except gas diffusion layer. GDL porosity was between 0.2 and 0.6, and a parametric work was conducted with modifications in the rate of 0.1 per modification. It is understood from the obtained current-voltage graphics that porosity change has different effects on low and high voltage fuel cells. Limit value was 0.63 V, and the highest current levels were obtained when the porosity was 0.3, however, performance of the fuel cell using gas diffusion layer with higher porosities (especially 0.6) increased. The results of the study conducted were shaped based on an experiment study in the literature and the model was verified.
Energy harvesting with the piezoelectric material integrated shoe
Abstract
In our times, the importance of energy efficiency is known by anyone. Besides, it is possible to reclaim the energy consumed by means of the developed technology. In this study, it is aimed to reclaim the energy transferred to the ground while people are walking in their daily lives by using piezoelectric materials, which convert mechanical energy into electrical energy. Having designed a sole to serve this goal, different piezoelectric materials are placed into the sole. Its behaviors under human weight are observed using computer software. For this reason, parametric analyses were carried out using 50, 60, 70, 80, and 90 kg, PZT-5H and PZT-8 piezoelectric ceramics and frames made of steel and aluminum materials as holding bodies of piezoelectric ceramics as human bodies. As a result of the analysis, a system of PZT-5H piezoelectric ceramic with a steel frame integrated into a human shoe of a weight of 90 kg used, showing that 0.4% of the applied force can be harvested to 1.43 mW of electrical power.
Analysis of fuel cell vehicles with advisor software
Abstract
In this study, fuel cell systems in automobiles were modeled by ADVISOR, and those models were analyzed through making comparisons. Fuel cell systems are essential parts of vehicles. Thus, before constructing fuel cell systems in a vehicle, analyzing the coherence of the system with vehicle is important in terms of cost and security. ADVISOR which has been developed by National Renewable Energy Laboratory (NREL) facilitates making comparisons of those kind of systems. In this article, the utilization of the software was denoted by an example and through making comparisons of fuel cell types, and the obtained results were evaluated.
Decision analysis application intended for selection of a power plant running on renewable energy sources
Abstract
Considering the damage caused by fossil and nuclear energy to the environment, the increasing prices of petroleum and natural gas, the fact that renewable energy sources will drain away in the next 50 years, the ever-growing energy demand and global warming, a worldwide shift towards renewable energy sources is inevitable. In this study, Turkey’s and the world’s existing situation, both technical and economic potential, impact on the environment, resource sustainability, technological maturity and social effects were examined. In order to fulfill Turkey’s energy needs, some renewable energy sources alternatives were taken into account. Application, selection and assessment of these alternatives were carried out through strengths, weaknesses, opportunities and threats (SWOT) analysis and The Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) methods.
English 
Turkish