Fig 9 - uploaded by Ariel Chiche
Content may be subject to copyright.
Source publication
Fuel cells are promising technologies for zero-emission energy conversion. They are used in several applications such as power plants, cars and even submarines. Hydrogen supply is crucial for such systems and using Proton Exchange Membrane Fuel Cell in dead-end mode is a solution to save hydrogen. Since water and impurities accumulate inside the st...
Contexts in source publication
Context 1
... of all, Fig. 9 and Fig. 10 show the results for the four additional experiments. Experiment 9 has a Time of 54.2 min with a distribution of around 10 min, as seen in Fig. 9. Fig. 10a shows that between each purge, the voltage of the stack varies, however there is no dramatic loss of voltage over a long time. This leads to a Perf of 1520. The results ...
Context 2
... of all, Fig. 9 and Fig. 10 show the results for the four additional experiments. Experiment 9 has a Time of 54.2 min with a distribution of around 10 min, as seen in Fig. 9. Fig. 10a shows that between each purge, the voltage of the stack varies, however there is no dramatic loss of voltage over a long time. This leads to a Perf of 1520. The results of experiment 10 (Exp 10), Figs. 9 and 10b, gives a Time of 10.0 min with a very small distribution of the times between two purges and a relatively stable ...
Citations
... Fuel cells are a promising solution, as they are environmentally friendly by no generating greenhouse gases during operation [6]. The use of low molecular weight alcohols such as methanol or ethanol as energy sources has numerous advantages, since for example these compounds can be easily handled, stored and transported [2,[7][8][9][10][11][12][13]. So far, the most widely used electrocatalyst in direct alcohol fuel cells (DAFCs) is platinum, due to its relatively high catalytic activity towards the methanol oxidation reaction (MOR) [14]. ...
... During the operation of the PEMFC system, nitrogen does not participate in the hydroxide chemical reaction but also flows to the anode of the stack due to the concentration difference and accumulates at the anode of the stack. To prevent nitrogen from entering the ejector through the circulation pipeline, it is significant to open the valve to purge nitrogen, but it causes hydrogen loss at the same time, so it is necessary to adopt purge control strategies to enhance the hydrogen utilization rate [123,124]. Some scholars use a fixed cycle to control the on-off of the valve to realize purging [125][126][127], but when PEMFC is at a high load, it is easy to lead to nitrogen and water accumulation; at low load, excessive hydrogen loss takes place with ease. ...
... This also further During the operation of the PEMFC system, nitrogen does not participate in the hydroxide chemical reaction but also flows to the anode of the stack due to the concentration difference and accumulates at the anode of the stack. To prevent nitrogen from entering the ejector through the circulation pipeline, it is significant to open the valve to purge nitrogen, but it causes hydrogen loss at the same time, so it is necessary to adopt purge control strategies to enhance the hydrogen utilization rate [123,124]. Some scholars use a fixed cycle to control the on-off of the valve to realize purging [125][126][127], but when PEMFC is at a high load, it is easy to lead to nitrogen and water accumulation; at low load, excessive hydrogen loss takes place with ease. ...
Proton exchange membrane fuel cells (PEMFCs) are attracting attention for their green, energy-saving, and high-efficiency advantages, becoming one of the future development trends of renewable energy utilization. However, there are still deficiencies in the gas supply system control strategy that plays a crucial role in PEMFCs, which limits the rapid development and application of PEMFCs. This paper provides a comprehensive and in-depth review of the PEMFC air delivery system (ADS) and hydrogen delivery system (HDS) operations. For the ADS, the advantages and disadvantages of the oxygen excess ratio (OER), oxygen pressure, and their decoupling control strategies are systematically described by the following three aspects: single control, hybrid control, and intelligent algorithm control. Additionally, the optimization strategies of the flow field or flow channel for oxygen supply speeds and distribution uniformity are compared and analyzed. For the HDS, a systematic review of hydrogen recirculation control strategies, purge strategies, and hydrogen flow control strategies is conducted. These strategies contribute a lot to improving hydrogen utilization rates. Furthermore, hydrogen supply pressure is summarized from the aspects of hybrid control and intelligent algorithm control. It is hoped to provide guidance or a reference for research on the HDS as well as the ADS control strategy and optimization strategy.
... Meanwhile, in 33) , the researchers developed a linear model between relative humidity, current load, and convection to determine the purging time of PEMFC working in a closed environment and found that with the model, the time between two purges can be maximized. However, based on the test results, the existing PEMFC control shows that the correlation between stack current and purging interval time is an exponential decay function, while the correlation between stack current and the drop of voltage stack is nonlinear. ...
The proton exchange membrane fuel cell (PEMFC) has a higher power density, so it is suitable to be utilized for powering electric vehicles (EVs) and supporting the grid’s power balance and voltage stability. As its load will vary during operation, the PEMFC system have to manage the fuel feed following load variations. In this study, a dead-end anode-type PEMFC system with a rated power of 1 kW is used to investigate its performance under current loading rates of 0–28 A in steady-state conditions. From the test results, the empirical models were derived and simulated in MATLAB. The test is conducted by measuring the PEMFC stack’s current, voltage, hydrogen flow rate, and purging behavior. The experimental results show a nonlinear correlation between stack current and voltage as well as its efficiency of hydrogen consumption to the electricity generated. The hydrogen flow rate exhibits a linear relationship to the generated power output in normal operation, neglecting the purging flow rate. Meanwhile, the total consumed hydrogen, including purging process, performs an exponential result which indicates more hydrogen was consumed for purging. Moreover, the observed purging behavior shows that the load current affects the purging interval time in an exponential decay manner. Some possible control methods are then discussed to control the hydrogen flow that dynamically follow the load variation and enable a not-complete purge; thus, the hydrogen consumption could be optimized and the excess hydrogen during the purging could be minimized.
... In order not to lose precious fuel due to oversupply and to improve water management [94], the system works in Dead End Anode (DEA) mode [108], and the recirculation of unreacted hydrogen is essential [13]. Pressure losses in the fuel cell imply the necessity of pressure control for the recirculation; to this end, active recirculation can be carried out using a blower. ...
... Pressure losses in the fuel cell imply the necessity of pressure control for the recirculation; to this end, active recirculation can be carried out using a blower. This component contributes to the vast majority of the energy consumption of the fuel supply system; moreover, among the BoP components, the blower's power consumption is in second or third place after the air compressor and the coolant pump (around 0.9 kW for an 80 kW fuel cell) [92,108,109]. As an alternative, a passive recirculation system based on a jet pump can be used. ...
... Pressure losses in the fuel cell imply the necessity of sure control for the recirculation; to this end, active recirculation can be carried out u blower. This component contributes to the vast majority of the energy consumption fuel supply system; moreover, among the BoP components, the blower's power cons tion is in second or third place after the air compressor and the coolant pump (arou kW for an 80 kW fuel cell) [92,108,109]. As an alternative, a passive recirculation s based on a jet pump can be used. ...
Fuel cell electric vehicles represent a possible solution to meet the objectives of the energy transition currently underway, which sees the replacement of combustion vehicles with low environmental impact vehicles. For this reason, this market is expected to markedly grow in the coming years. Currently, the most suitable fuel cell technology for both light and heavy transport applications is the Proton Exchange Membrane fuel cell. This review provides a comprehensive description of the state of the art of fuel cell electric vehicles at different levels: vehicle configuration, fuel cell stack, and all the necessary operation systems. The current advantages and limits of the mentioned technology are highlighted, referring to recent studies aimed at optimizing the efficiency of the system and providing future perspectives.
... However, small amounts of reacting gases are also released during the purging process. Therefore, the number of recovering cycles should be minimized for safety and maximum fuel efficiency [4][5][6][7]. ...
... 4. The catalyst layer is treated as a surface where the electrochemical reactions take place. 5. The membrane effect is only ohmic with a constant resistivity because its water content remains unchanged due to relatively short time intervals among two consecutive purges. ...
... 4 Obtained values of unknown parameters through fitting the steady-state model to V-I test measurements. 5 Obtained values of unknown parameters through fitting the impedance model to EIS test measurements. ...
... On the other hand, advantages as low operating temperature, small size, and simple design are appropriate features for stationary and mobile applications. These advantages make the power generation through this technology attractive [1][2][3]. Nevertheless, the PEMFC generates a low output voltage and suffers from the fuelstarvation phenomenon, which refers to the absence of fuel for short instants of time, causing an abrupt drop in the output voltage [4]. ...
... The Nuvera's Orion® PEMFC technology [53], assembled in 2014, has metallic bipolar plates and an open flow field, to increase the active area of each cell Membrane-Electrode Assembly (MEA). The anode is Dead-end and the anodic flow is recirculated, therefore anodic purges are planned to eliminate impurities and water accumulated during operation and to avoid excessive FC degradation [54]. In particular, the purging was initially controlled by the current, that used to regulate the opening and closing time of the dedicated valve with a logic defined by the FC supplier. ...
This work shows the results of the experimental assessment of the HI-SEA joint laboratory between Fincantieri, the main Italian shipbuilder, and the University of Genova. The HI-SEA system is a 240 kW real-scale test rig complete of auxiliaries, made up of 8 Proton Exchange Membrane Fuel Cell stacks installed on two parallel branches, which can operate independently or in parallel by means of two dedicated DC/DC converters. The experimental assessment is performed by considering: (i) Stationary performance; (ii) dynamic performance; (iii) a maritime operative profile defined together with Fincantieri. The experimental results obtained in this work demonstrated that the system can successfully respond to static, dynamic, and typical maritime operative load profiles. It was also assessed the ability of the system to work simultaneously with two parallel branches, by means of two DC/DC converters, which represents a clear advantage in terms of load sharing and redundance onboard for security issues. Furthermore, the present study gives important advice and criteria for the design, construction, and control of similar Fuel Cell complete systems for maritime applications, which is particularly relevant considering that experimental studies on complete Fuel Cell systems is still limited.
... By optimizing the fuel cell system (size reduction of parts and elimination of potentially unnecessary components) and the fuel cell assembly, the fuel cell pressure vessel may become significantly smaller, offering more space for hydrogen and oxygen storage. Furthermore, the operation of the fuel cell in dead-end mode [63] and with pure oxygen (not air) will increase stack efficiency significantly. ...
... Fuel-cell technologies address both environmental and energy issues [37]. In particular, PEMFC is a promising technology for clean energy generation [6]. The main characteristics of PEMFCs are zero-emission energy conversion, low operating temperature (60 Ce100 C), high current density, low maintenance, quiet operation, high efficiency in the energy conversion (more than 50%), and relative low size [8,24,34]. ...
The electrolyte membrane fuel cell (PEMFC) is characterized by a low and unregulated output voltage; thus, an interface between source and load is required for processing the generated energy by the PEMFC. In this paper, a solution for processing the energy generated by a PEMFC is given. A switching regulator is developed by using a quadratic boost converter with a single switch (QBC-SS). The controller for the QBC-SS is designed using average current-mode (ACM) control, which is easy to implement using analog circuits. The proposed switching regulator ensures high conversion ratios, output voltage regulation, adequate dynamic performance, and stability. On the other hand, a model with static characteristics for the PEMFC electrical behavior is proposed, which can be used for modeling and control purposes. This model consists of three parameters, which are computed using experimental data of the PEMFC stack. A laboratory prototype of 400 W is used to verify the analytical results. As an input source, a PEMFC system is used. The output voltage of the PEMFC stack ranges from 41 V to 24 V, which depends on the generated current. Experimental results applying load step changes and frequency response analysis are shown.
... As the anode is Dead-end and the anodic flow is recirculated, anodic purges are needed to eliminate impurities and water accumulated during operation. Otherwise, this operative condition could affect voltage and create FC degradation [45]. The FC stacks are auto hydrated, which makes thermal management crucial to maintain a good humidity equilibrium inside the cells, but it gives the advantage of saving space onboard [46]. ...
New policies and strict emission limits in the transports sector result in a gradual switch towards alternative fuels and hydrogen is getting attention: fuel cell systems are considered ideal energy converters of the next future. As the interest is rising in Proton Exchange Membrane Fuel Cells (PEMFC), there is a need for experimental research and dedicated laboratories on systems designed with Balance of Plant. In this context, the HI-SEA Laboratory (240-kW PEMFC by Nuvera FC, a joint between the University of Genoa-Fincantieri) was born. In this paper, the tuning of the laboratory to simulate a ship-likely environment is addressed, looking at the main problematics and resolutions, related to the cathodic line and the cooling control. Some guidelines are defined to install a PEMFC system onboard a ship exploiting the existing infrastructure. Thanks to the experimental campaign, a stack voltage model previously validated is employed to evaluate the performance of the system.
