Design of experiment study of the parameters that affect performance of three flow plate configurations of a proton exchange membrane fuel cell

Low temperature hydrogen fuel cells are electrochemical devices which offer a promising alternative to traditional power sources. Fuel cells produce electricity with a reaction of the fuel (hydrogen) and air. Fuel cells have the advantage of being clean; only producing water and heat as by products. The efficiency of a fuel cell varies depending on the type; SOFC with CHP for example, can have a system efficiency of up to 65%. What the Authors present here is a comparison between three different configurations of flow plates of a proton exchange membrane fuel cell, the manufacturer’s serpentine flow plate and two new configurations; the maze flow plate and the parallel flow plate. A study of the input parameters affecting output responses of voltage, current, power and efficiency of a fuel cell is performed through experimentation. The results were taken from direct readings of the fuel cell and from polarisation curves produced. This information was then analysed through a design of experiment to investigate the effects of the changing parameters on different configurations of the fuel cell’s flow plates. The results indicate that, in relation to current and voltage response of the polarisation curve and the corresponding graphs produced from the DOE, the serpentine flow plate design is a much more effective design than the maze or parallel flow plate design. It was noted that the parallel flow plate performed reasonably well at higher pressures but over all statically the serpentine flow plate performed better

Representative model and flow characteristics of open pore cellular foam and potential use in proton exchange membrane fuel cells

This study develops a Representative Unit Cell Structure (RUCS) model for Open Pore Cellular Foam (OPCF) material, based on a dodecahedron cell. Pressure, velocity and flow regime analysis is performed on simulation results of six different OPCFs, (10, 20, 30, 40, 45, 80 and 100ppi), at five different inlet velocities (1m/s, 3m/s, 6m/s, 9m/s & 12m/s). Pressure drop results were verified by numerical models (Dupuit-Forchheimer, Ashby and Fourie and Du Plessis mathematical models) and experimental results from literature. From this study OPCF material can have benefits if used in a PEM fuel cell; in place of or in conjunction with conventional flow plates. It is concluded that OPCF materials can reduce the permeability of the gas flow through a flow plate, creating a more tortuous path for the fluid, allowing for diffusion plus convection based flow, unlike conventional flow plates

The hydrography and circulation of the upper 1200 meters in the tropical North Atlantic during 1982-91

We assemble a collection of 7591 conductivity-temperature-depth stations in the tropical Atlantic between 5S and 20N for the period 1982–1991 using data from the Soviet SECTIONS program enhanced by contributions primarily from the WESTRAX and FOCAL/SEQUAL programs. Most of the stations are west of 30W, forming a series of 21 surveys. In addition there were five multi-ship basinwide surveys, each taking 1.5–3 months to complete. The quality of the SECTIONS data is discussed and comparisons between the data sets are shown. Within the pycnocline, southern water is distinguished by salinity that is 0.3 psu lower than its northern counterpart at the same density. This difference allows us to distinguish the origin of pycnocline water. Based on this information together with geostrophic analysis we confirm that much of the water transported across the equator in the North Brazil Current retroflects eastward south of 8N. In summer and fall the water of the North Brazil Current merges with the water of the North Equatorial Current to form the North Equatorial Countercurrent, whose axis shifts southward with depth. East of 35W part of the mass transport in the Countercurrent is lost to the equatorial zone, while the rest continues eastward. During winter and spring eastward currents are found in two latitude bands, a surface current between 5–10N and a weaker current south of 5N confined to the thermocline. This latter North Equatorial Undercurrent has no surface expression in winter. During the summer and fall the northern boundary of Southern Hemisphere water at pycnocline depths is given by the North Equatorial Countercurrent. During the rest of the year the northern boundary of Southern Hemisphere water only penetrates to the edge of the weaker North Equatorial Undercurrent south of 5N. The availability of ten years of data allows us to examine aspects of year-to-year variability. Among these results the data set reveals strong meandering of the North Equatorial Countercurrent between 42W and 35W during the summer of 1987. The meandering also appears in contemporaneous Geosat altimetry. Another unusual feature occurred in the summer 1986 when there was a strong thermocline current transporting water northward at the rate of 26 Sv. Water mass analysis shows that this current was the result of a pressure gradient set up by an intrusion of warm low-salinity water from the Southern Hemisphere. The fact that this high transport occurred in the interior ocean suggests that interior flows must be monitored during any attempt to observe meridional transports of mass or heat

Interannual to Decadal Variability of Atlantic Water in the Nordic and Adjacent Seas

Warm salty Atlantic Water is the main source water for the Arctic Ocean and thus plays an important role in the mass and heat budget of the Arctic. This study explores interannual to decadal variability of Atlantic Water properties in the Nordic Seas area where Atlantic Water enters the Arctic, based on a reexamination of the historical hydrographic record for the years 1950-2009, obtained by combining multiple data sets. The analysis shows a succession of four multi-year warm events where temperature anomalies at 100m depth exceed 0.4oC, and three cold events. Three of the four warm events lasted 3-4 years, while the fourth began in 1999 and persists at least through 2009. This most recent warm event is anomalous in other ways as well, being the strongest, having the broadest geographic extent, being surface-intensified, and occurring under exceptional meteorological conditions. Three of the four warm events were accompanied by elevated salinities consistent with enhanced ocean transport into the Nordic Seas, with the exception of the event spanning July 1989-July 1993. Of the three cold events, two lasted for four years, while the third lasted for nearly 14 years. Two of the three cold events are associated with reduced salinities, but the cold event of the 1960s had elevated salinities. The relationship of these events to meteorological conditions is examined. The results show that local surface heat flux variations act in some cases to reinforce the anomalies, but are too weak to be the sole cause

Design & development of innovative proton exchange membrane fuel cells

The research undertaken in this thesis is concerned with the design and development of Proton Exchange Membrane (PEM) fuel cells and provides a body of information for continued PEM fuel cell development, which will ideally aid in the future commercialisation of these electrochemical devices. Through a combination of numerical analysis, computational fluid dynamic modelling and experimental work, effective flow plate designs, flow field configurations and materials are analysed and new innovative designs are proposed. The flow plate of a PEM fuel cell is one of the most important structures in these devices. Effective design of the flow plate will aid in the optimisation of PEM fuel cell technology. Due to the low operational temperature of PEM fuel cells, water species can form in the flow field and this can affect their performance. Two phase flow models were used to study this phenomena. These models show how the water flooding in flow field channels can hinder the mass transport if these are not properly designed, leading to reduced performance, increased heat and reduced fuel utilisation. A high speed camera technique in an ex situ apparatus was used to validate the model and water mitigation methods are proposed. From the culmination of the analysis performed a novel application of open pore cellular metal foam as a flow plate material is proposed in this thesis. A model is developed, to simulate this relatively new material and extensive pressure analysis and flow modelling has been completed using this model. Computational fluid dynamic modelling, with an additional electrochemical PEM fuel cell module, has been carried out on conventional double channel flow plates and open pore cellular foam flow plates. Flow regimes, pressure analysis, water accumulation, oxygen concentration, fuel utilisation, current & voltage curves and cell temperature profiles are analysed. The PEM fuel cell model with open pore cellular metal foam flow plate performs in excess of a 55% improvement on the current density of the bench mark double serpentine flow plate under the same operating conditions at 0.7 volts. All of the above multi physical phenomena match very well to the experimental results. This information is new to the area and should help optimise PEM fuel cell performance

Estimating vehicle emissions from road transport, case study: Dublin City

Air pollution is becoming a very important issue for the transportation sector, particularly car emissions in urban areas, and there is much interest in evaluating the actual level of emissions. In this paper, a case study of a standard driving cycle in the urban area of Dublin city is presented. On-road, speed-time data was extracted by an on-board diagnostic tool, and saved into a data acquisition package. Firstly, the driving cycle was established for the urban area of the city; one car traveling different routes has been employed to implement this research and some representative results have been achieved. The second part of the project was to estimate the emissions from the same car using the driving cycle obtained and compare the results with those obtained by a gas analyzer attached to the car simultaneously in order to validate the methodology used in this paper. A representative driving cycle reflecting the real-world driving conditions is proposed and estimated vehicle emissions were compared with measured results. The method is easy to follow and the results are in a good fit to the estimated values

Design and development of proton exchange membrane fuel cell using open pore cellular foam as flow plate material

This paper reports the design and development of a Proton Exchange Membrane (PEM) fuel cell using open pore cellular metal foam as the flow plate material. Effective housing designs are proposed for both hydrogen and oxygen sides and through the application of Computational Fluid Dynamic (CFD) modelling and analysis techniques the flow regime through the open pore cellular metal foam flow plate are identified. Based on the CFD results the best anode housing design was selected and manufactured. The fuel cell was assembled and tested and the findings are reported

Role of deposit-feeding sea cucumbers in integrated multitrophic aquaculture: progress, problems, potential and future challenges

There is significant commercial and research interest in the application of sea cucumbers as nutrient recyclers and processors of particulate waste in polyculture or integrated multitrophic aquaculture (IMTA) systems. The following article reviews examples of existing IMTA systems operating with sea cucumbers, and details the role and effect of several sea cucumber species in experimental and pilot IMTA systems worldwide. Historical observations and quantification of impacts of sea cucumber deposit-feeding and locomotion are examined, as is the development and testing of concepts for the application of sea cucumbers in sediment remediation and site recovery. The extension of applied IMTA systems is reported, from basic piloting through to economically viable farming systems operating at commercial scales. The near-global recognition of the ecological and economic value of deposit-feeding sea cucumbers in IMTA applications within existing and developing aquaculture industries is discussed. Predictions and recommendations are offered for optimal development of sea cucumber IMTA globally. Future directions within the industry are indicated, and key areas of ecological, biological and commercial concern are highlighted to be kept in mind and addressed in a precautionary manner as the industry develops

Three-dimensional proton exchange membrane fuel cell model:Comparison of double channel and open pore cellular foam flow plates

https://egrove.olemiss.edu/aicpa_prof/1241/thumbnail.jp