Jan Van Herle

Related publications (285)

Fast online diagnosis for solid oxide fuel cells: Optimisation of total harmonic distortion tool for real-system application and reactants starvation identification

Gerald Hammerschmid, Hamza Moussaoui, Jan Van Herle

This study investigates the potential application of total harmonic distortion (THD), as a fast online monitoring tool, to identify the early signs of failure modes in solid oxide fuel cells (SOFC). Indeed, the timely detection and identification of faults is crucial for applying mitigation strategies to avoid irreversible damage and increase the system lifetime. Two of the most common faulty conditions are considered in this work, namely fuel and air starvation. This experimental work aims at progressively triggering these errors in a controlled manner, by following different realistic scenarios, and recording THD values on a frequent basis. Several well -established laboratory monitoring tools, like electrochemical impedance spectroscopy (EIS), complemented by the distribution of relaxation times (DRT) are used to analyse and support the interpretation of the THD measurements. A sensitivity analysis on the THD parameters, namely the signal amplitude and the number of harmonics, is carried out to identify the optimal combination of parameters and achieve the best faults detectability. Finally, the impact of the fuel flow direction and the operating temperature are examined. The results of this work are summarised as practical guidelines to better employ the THD technique to identify the early warning signs of reactants' starvation.

ELSEVIER2023

How Acid Washing Nickel Foam Substrates Improves the Efficiency of the Alkaline Hydrogen Evolution Reaction

Peter Hugh Middleton, Suhas Nuggehalli Sampathkumar, Jan Van Herle

Nickel foam substrates are frequently utilised as porous 3D substrates for renewable energy applications. The preparation of these substrates usually includes an acid-washing step, but the degree to which this step affects the final electrochemical performance after spray-coating a catalyst ink is unreported. Herein, we report the effects of acid washing through physicochemical and electrochemical characterisation. The electrochemical performance was determined through repeated measurements of catalyst-coated nickel foam substrates both with and without the initial step of acid washing. It was found that acid washing increased the current density by 17.9% for the acid-treated MoS2-coated nickel foam electrode. This increment was affiliated with an electrochemically active surface area that increased by 11.2%, and a Tafel analysis indicated that the acid-treated MoS2-coated electrodes facilitated the initial water dissociation step of the hydrogen evolution reaction with greater ease. Similar effects were also discovered for acid-treated PtIr(1:3)/C-coated nickel foam substrates. The stability was also improved; the degradation rate was reduced by 18.9% for the acid-treated MoS2-coated electrodes. This demonstrates the utility of acid washing nickel foam electrodes.

MDPI2023

Lab-Scale Investigation of the Integrated Backup/Storage System for Wind Turbines Using Alkaline Electrolyzer

Hossein Pourrahmani, Jan Van Herle

The depletion of fossil fuel sources has encouraged the authorities to use renewable resources such as wind energy to generate electricity. A backup/storage system can improve the performance of wind turbines, due to fluctuations in power demand. The novelty of this study is to utilize a hybrid system for a wind farm, using the excess electricity generated by the wind turbines to produce hydrogen in an alkaline electrolyzer (AEL). The hydrogen storage tank stores the produced hydrogen and provides hydrogen to the proton-exchange membrane fuel cell (PEMFC) to generate electricity once the power demand is higher than the electricity generated by the wind turbines. The goal of this study is to use the wind profile of a region in Iran, namely the Cohen region, to analyze the performance of the suggested integrated system on a micro scale. The output results of this study can be used as a case study for construction in the future, based on the exact specification of NTK300 wind turbines. The results indicate that, with the minimum power supply of 30 kW from the wind turbines on a lab scale, the generated power by the PEMFC will be 1008 W, while the maximum generated hydrogen will be 304 mL/h.

MDPI2023

Readiness evaluation of SOFC-MGT hybrid systems with carbon capture for distributed combined heat and power

Michele Gaffuri, Victoria Xu Hong He, Jürg Alexander Schiffmann, Jan Van Herle

The aggravation of climate change calls for the timely development and implementation of highly efficient, renewable, zero- or negative-emission energy solutions with high technological readiness and feasibility levels. Solid oxide fuel cells (SOFC) constitute an appealing solution since they are close to commercial viability and can generate electricity and heat from a wide variety of fuels, for instance gas from renewable sources. In this paper, we consider the coupling of SOFC with Brayton cycles via micro gas turbines (MGT) due to their suitability for a compact small-scale energy system (10–100 kWe) and their high readiness level as stand-alone systems and in combination with suitable carbon capture and storage (CCS) technologies. An integrative literature review approach is used to qualitatively evaluate different SOFC-MGT integration strategies and CCS to devise a suitable small-scale SOFC/MGT-CCS system. A promising layout of a hybrid system based on atmospheric pressure SOFC and MGT has been identified, which uses an inverted Brayton cycle to expand the SOFC outlet gases. This system has the potential to achieve similar efficiency as the widely researched pressurized system with less complexity. Further, implementing an oxy-combustion process between the SOFC and the MGT inlet, a pure stream of CO2 is obtained, easing its capture.

2023

Activation of stainless steel 316L anode for anion exchange membrane water electrolysis

Peter Hugh Middleton, Suhas Nuggehalli Sampathkumar, Jan Van Herle

The increased emphasis on renewable energy has resulted in a surge of R&D efforts into hydrogen and battery research. The intensive electrochemical environment surrounding the anodic oxygen evolution reaction (OER) has plagued both the activity and stability of the catalytic layer, substrate and porous transport layer, ultimately affecting both these industries. Herein, we report the benefits of potential cycling (PC) a 316L stainless steel felt porous transport layer (PTL) for use in anion exchange membrane water electrolysis. The PC increased surface roughness and created a CrFe5Ni2-OxHy layer through the oxidation of iron as shown by SEM, EDS, XPS, XRD and Raman spectroscopy. Post-PC tests in a three-electrode setup reveal a approximate to 68% decline in polarisation resistance, which is reflected in its performance when employed as an anode in an anion exchange membrane water electrolyser (AEMWE). Overall, potential cycling the PTL under anodic conditions resulted in an improved performance when tested in a AEMWE. Implementing this treatment on stainless steel anodes could be considered to achieve an improved AEMWE performance.

ELSEVIER SCIENCE INC2022

Degradation study of a reversible solid oxide cell (rSOC) short stack using distribution of relaxation times (DRT) analysis

Philippe Aubin, Stefan Diethelm, Suhas Nuggehalli Sampathkumar, Maria del Mar Perez Fortes, Jan Van Herle

Reversible solid oxide cells (rSOC) can convert excess electricity to valuable fuels in electrolysis cell mode (SOEC) and reverse the reaction in fuel cell mode (SOFC). In this work, a five - cell rSOC short stack, integrating fuel electrode (Ni-YSZ) supported solid oxide cells (Ni-YSZ parallel to YSZ vertical bar CGO parallel to LSC-CGO) with an active area of 100 cm(2), is tested for cyclic durability. The fuel electrode gases of H-2/N-2:50/50 and H-2/H2O:20/80 in SOFC and SOEC mode, respectively, are used during the 35 reversible operations. The voltage degradation of the rSOC is 1.64% kh(-1) and 0.65% kh(-1) in SOFC and SOEC mode, respectively, with fuel and steam utilisation of 52%. The post-cycle steady-state SOEC degradation of 0.74% kh(-1) suggests improved lifetime during rSOC conditions. The distribution of relaxation times (DRT) analysis suggests charge transfer through the fuel electrode is responsible for the observed degradation. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.

PERGAMON-ELSEVIER SCIENCE LTD2022

Evaluation Criterion of Proton Exchange Membrane (ECPEM) fuel cells considering inserted porous media inside the gas flow channel

Hossein Pourrahmani, Jan Van Herle

The focus of this study is to evaluate the effects of porous media inside the gas flow channel of Proton Exchange Membrane Fuel Cells (PEMFC) on four different output parameters of voltage, power density, pressure drop, and Nusselt number (Nu) considering the impacts of its thickness, viscous resistance, and current density. Although it is proved that the new design will improve the convective heat transfer, there have not been studies to evaluate the effects of this porous layer on the electrochemical performance and heat transfer simultaneously. The results showed that viscous resistance has by far the highest impact on the power densities in high current densities while thicker inserted porous layer improves the performance. Results also demonstrate that a parameter is needed to consider all these output parameters at the same time, hence the Evaluation Criterion of Proton Exchange Membrane (ECPEM) is defined using artificial neural network (ANN) modeling. Single-objective optimization of the ECPEM is developed using the ANN models to produce 250,000 data. The optimum value of ECPEM was obtained 78.88 in the thickness of 500 mu m and the viscous resistance of 2,111,000 (1/m(2)) while the current density is equal to 0.65 (A/cm(2)).

PERGAMON-ELSEVIER SCIENCE LTD2022

Integrated solar-driven high-temperature electrolysis operating with concentrated irradiation

Stefan Diethelm, Sophia Haussener, Meng Lin, Clemens Gregor Suter, Jan Van Herle

High-temperature electrolysis for reducing H2O (and CO2) to H2 (and CO) converts concentrated solar energy into fuels and chemical feedstock. We invented an integrated reactor concept comprising a solar cavity receiver for reactant heating, a solid oxide electrolyzer (SOE) stack for water electrolysis, and concentrated photovoltaic (PV) cells for the SOE stack’s electricity demand. A numerical model compared thermoneutral and endo/exothermal operation of the SOE stack. Without heat recovery, we predicted a maximum solar-to-hydrogen (STH) efficiency of 19.85% (assuming 20% PV efficiency and 20% heat losses in the solar cavity receiver) and preferentially endothermal operation. Heat recovery further improved the performance. We demonstrated a 2.5 kW (17% electrical and 83% thermal input) reactor, incorporating a commercial 16-cell Ni/YSZ/LSM SOE stack into a double-helical solar cavity receiver, with 3.33% STH efficiency (assuming 20% PV efficiency). The experimentally supported analysis indicates that endothermal operation increases the performance and predicts STH efficiencies encouraging intensified research and technology development.

2022

Optimization and dynamic responses of an integrated fuel cell and battery system for an 800 kW ferry: A case study

Martin Daniel Gay, Hossein Pourrahmani, Jan Van Herle

The recent targets by different countries to stop the sales or registrations of internal combustion engines (ICE) have led to the further development of battery and fuel cell technologies to provide power for different applications. The main aim of this study is to evaluate the possibility of using an integrated Lithium-Ion battery and proton exchange membrane fuel cell (PEMFC) as the prime mover for a case study of a 800 kW ferry with a total length of 50.8 m to transport 780 passengers for a distance of 24 km in 70 min. Accounting for five types of Lithium-Ion batteries and different numbers of PEMFCs, twenty-five scenarios are suggested based on a quasi-static model. To perform the optimization, the Performance Criterion of the Fuel cell-Battery integrated systems (PCFB) is introduced to include the effects of the sizes, weights, costs, hydrogen consumption, efficiency, and power in addition to the number of fuel cells and the battery capacity. Results indicate that the maximum PCFB value of 10.755 (1/kg(2)m(3)

) can be obtained once the overall size, weight, efficiency, hydrogen consumption, and cost of the system are 18 m(3), 11160 kg, 49.25%, 33.6 kg, and 119.58 k

ELSEVIER2022

Organic Rankine Cycle as the Waste Heat Recovery Unit of Solid Oxide Fuel Cell: A Novel System Design for the Electric Vehicle Charging Stations Using Batteries as a Backup/Storage Unit

Hossein Pourrahmani, Jan Van Herle, Chengzhang Xu

The novelty of this study is to suggest a novel design for electric vehicle charging stations using fuel cell technology. The proposed system benefits from the Organic Rankine Cycle (ORC) to utilize the exhaust energy of the Solid Oxide Fuel Cell (SOFC) stacks in addition to the Lithium-Ion battery to improve the efficiency by partial-load operation of the stacks at night. The study is supported by the thermodynamic analysis to obtain the characteristics of the system in each state point. To analyze the operation of the system during the partial-load operation, the dynamic performance of the system was developed during the day. Furthermore, the environmental impacts of the system were evaluated considering eighteen parameters using a life-cycle assessment (LCA). LCA results also revealed the effects of different fuels and working fluids for the SOFC stacks and ORC, respectively. Results show that the combination of SOFC and ORC units can generate 264.02 kWh with the respective overall energy and exergy efficiencies of 48.96% and 48.51%. The suggested 264.02 kWh contributes to global warming (kg CO2 eq) by 5.17 x 10(5), 8.36 x 10(4), 2.5 x 10(5), 1.98 x 10(5), and 6.79 x 10(4) using methane, bio-methanol, natural gas, biogas, and hydrogen as the fuel of the SOFC stacks.

MDPI2022

Optimization and dynamic responses of an integrated fuel cell and battery system for an 800 kW ferry: A case study

Martin Daniel Gay, Hossein Pourrahmani, Jan Van Herle

) can be obtained once the overall size, weight, efficiency, hydrogen consumption, and cost of the system are 18 m(3), 11160 kg, 49.25%, 33.6 kg, and 119.58 k

ELSEVIER2022