Pregled znanstvenih napredaka u učinskoj elektronici usmjerenih ka osiguravanju efikasnog rada i dužeg životnog vijeka PEMgorivih ćelija

This article focuses on the main issues that affect the lifetime and performance of proton-exchange membrane fuel cells. The short lifespans of these fuel cells represent a barrier to their massive commercialization and usage in mobile and stationary applications. As fuel cell is a very complex system, a lot of knowledge of different areas is required, such as chemistry, electricity and mechanics, in order to completely understand its operation and all the problems that can occur during it. It is for this reason that an interdisciplinary approach needs to be taken when designing fuel-cell energy systems. This paper focuses on identifying and solving those issues that negatively affect the lifetime and performance of fuel cells. It is hoped that this article would be a valuable aid for power electronics’ researchers and engineers for better understanding the presented issues and a useful guide for solving them with the use of proper power electronic-devices. Initially, the basic operation and structure of a proton-exchange membrane fuel cell is explained. Three main issues that can occur during operation of a mobile or stationary fuel cell energy system are pointed out and discussed in details, on the basis of the state-of-the-art on fuel cell technology. These issues are poor water management, reactant gas starvation and fuel cell current ripple. This article provides answers as to why they occur, how they affect the fuel cell, how they can be mitigated, and what are the future trends within this research field.Članak se osvrće na ključna pitanja koja utječu na vrijeme rada i performanse gorivih ćelija s polimernom membranom kao elektrolitom. Kratak životni vijek gorivih ćelija takve vrste prepreka je njihovoj komercijalizaciji i masovnoj upotrebi u mobilnim i stacionarnim stanicama. Budući da su gorive ćelije komplicirani sustavi potrebno je znanje iz raznih područja kemije, elektrotehnike i mehanike da bi se u potpunosti mogao razumjeti njihov način rada i problemi koji se događaju. Upravo je zbog toga multidisciplinarni pristup nužnost pri razvoju sustava koji koriste gorive ćelije. Ovaj je članak usmjeren prema identifikaciji i rješavanju onih problema koji negativno utječu na životni vijek i performanse gorivih ćelija. Autori se nadaju da će se članak pokazati kao korisna pomoć i vodič istraživačima i inženjerima u domeni učinske elektronike pri susretu s navedenim problemima. Objašnjen je način rada i struktura gorive ćelije s polimernom membranom kao elektrolitom. Izložena su, i diskutirana do u detalje, tri glavna problema sa stajališta trenutačnih spoznaja u području učinske elektronike. Ti problemi su: loše upravljanje vodom, nestanak reaktantnog plina i strujni trzaji u gorivim ćelijama. Objašnjeno je zašto se ovi problemi događaju, kako utječu na gorivu ćeliju, kako ih se može spriječiti i koje su buduće perspektive istraživanja

An investigation of the ionophoric characteristics of destruxin A

Destruxin A, a cyclohexadepsipeptide related to the enniatins and beauvericin, exhibits ionophoric properties. Calcium ion mobilization across liposomal membrane barriers, for example, has been demonstrated using the calcium ion-sensitive dyes Arsenazo III and Fura-2. Initial molecular mechanics/molecular dynamics calculations indicate the potential for destruxin A to form a coordination complex with calcium in which the divalent cation is bound at the center of a sandwich formed by two molecules of destruxin A. This novel calcium ion binding may help explain the diverse biological effects exhibited by the destruxins

Modelling of the proton exchange membrane fuel cell in steady state

International audienc

New PEMFC behaviour law

International audienc

An innovating application of PEM fuel cell: Current source controlled by hydrogen supply

International audienc

ผลกระทบของ Knudsen Diffusion ต่อแบบจำลองของเซลล์เชื้อเพลิงชนิดเมมเบรนแลกเปลี่ยนโปรตอน

Davat1AbstractWith an aim of optimizing the operating points of the proton exchange membrane fuel cell (PEMFC), it is necessary to understand physical mechanisms of the cell. The physical mechanisms which play the important roles in the PEMFC are the gas transport in the gas diffusion layer and the proton transport in the membrane. Tremendous equations, which require massive computational cost, are used to describe the operations of the cell. However, the Knudsen diffusion, which is one kind of the transport mechanism in the fuel cell, is usually be neglected to reduce the computational cost. This paper presents a comparative study between two types of one-dimensional (1-D) steady isothermal PEMFC models; one of which is include the effect of the Knudsen diffusion and the other one is not. The numerical results of the transport phenomena from both models have been presented. Membrane resistances from each case are computed to evaluate the effect of neglecting the Knudsen diffusion. The result has shown that neglecting the Knudsen diffusion causes about 9% relative error to the membrane resistances, which is quite significant

Online humidification diagnosis of a PEMFC using a static DC–DC converter

International audienc

Technical feasibility assessment of a PEM fuel cell refrigerator system

PEM Fuel Cells (PEMFCs), fueled by hydrogen, are electrochemical devices that convert hydrogen to useful power and two by-products: heat and water. They cover an important part of power applications namely in the transportation area, and in other practical applications that are either stationary or portable. In particular, the domestic refrigerator is one of the daily and indispensable applications but with a high-energy demand due to the high running time cycles. This work is a technical assessment of the feasibility of building a coupled “PEM Fuel Cell – Refrigerator” system. Real technical data for the refrigerator are collected, processed and evaluated. The obtained results show reasonable flows consumption rates. In fact, the refrigerator requires a flow rate of 1.607 slpm of hydrogen and 8 slpm of air at a pressure of respectively 3 atm and 1 atm. The water is produced at a rate of 1.285 10−3 slpm. The annual amount of hydrogen consumed by the refrigerator is estimated to 28, 47 kg. The energy provided to the refrigerator is about 130 W and the energy needed by the air compressor is 28, 24 W. A technical solution is suggested at the end of this work to reduce the start and stop cycles of the fuel cell