• Energy Research

In this paper, the integration of a small SOFC commercial system into the fuselage of a mini Unmanned Aerial Vehicle (UAV) is presented. As a design constrain, the SOFC system has to be installed inside the UAV fuselage with the lowest possible offset, to reduce the volume and mass of the UAV. Due to the high operating temperature of the SOFC (800-1000 °C), the external temperature of the system is always about few hundred Celsius degrees. Due to this, malfunctioning of the SOFC system and hot spots on the fuselage shell can occur. For this reason, it is important to ensure a proper ventilation of the air volume inside the UAV fuselage. To deal with these issues, experimental and Computational Fluid dynamic studies were carried out to investigate for a correct SOFC system integration and operation in a confined environment. As a result, the optimal airflow for a safe operation of the SOFC system was determined and the behaviour of the temperature and air stream inside the fuselage was highlighted. In addition, NACA air intakes were designed on the basis on the experimental and numerical evidences, to provide a proper cooling of the SOFC system installed into the fuselage.

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The ultimate aim of the HYScale project is the development of a large-area (400 cm²) stack with a power of 100 kW. This requires the upscaling and optimization of membranes, ionomers and electrodes (WP2). In the first eighteen months of the project, WPs 2 and 3 have been working closely together to take this first important step towards achieving the 100 kW stack, i.e. the assembly of a large-area single cell using MEAs based entirely on components produced within the project, and the investigation of their electrochemical performance and stability. This deliverable reports initial results obtained at CNR and DLR using a small single cell, primarily investigating the issue of which material to use as the PTL at the cathode. It goes on to describe findings obtained using the large cell (ca. 400cm2), with which the AionFLX membrane developed at CENmat is compared to the PiperION benchmark (CNR).

Hydrogen production through polymer electrolyte membrane water electrolysis was investigated at high current density (4 A cm). A PtCo recombination catalyst-based membrane-electrode assembly (MEA) was assessed in terms of performance, efficiency and durability. The electrolysis cell consisted of a thin (50 µm) perfluorosulfonic acid membrane and low platinum group metals (PGM) catalyst loadings (0.6 mg PGM cm). An unsupported PtCo catalyst was successfully integrated in the anode. A composite catalytic layer made of IrRuOx and PtCo assisted both oxygen evolution and oxidation of hydrogen permeated through the membrane. The cell voltage for the recombination catalyst-based MEA was about 30 mV lower than the bare MEA during a 3500 h durability test. The modified MEA showed low performance losses during 3500 h operation at high current density (4 A cm) with low catalyst loadings. A decay rate of 9 µV/h was observed in the last 1000 h. These results are promising for decreasing the capital costs of polymer electrolyte membrane electrolysers. Moreover, the stable voltage efficiency of about 80% vs. the high heating value (HHV) of hydrogen at 4 A cm, here achieved, appears very promising to decrease operating expenditures.

This paper covers the research activities performed at the CNR Institute for Advanced Energy Technologies "Nicola Giordano", aimed at developing and testing a biogas steam reforming reactor. A mathematical model has been developed in order to describe, the performance of the above-cited steam reforming reactor (packed bed). To study the effects on reaction performance, a parametric analysis was performed varying operating conditions such as inlet temperature and reagent molar ratio. The model was validated by comparing the calculated data with the experimental data obtained with a proprietary Ni/ CeO2 based catalyst in packet bed micro-scale reactor at different T ¼ 700e900 C, S/C ¼ 1e5 and GHSV ¼ 30,000 h1, showing a good agreement between the experimental and theoretical results.

A nanosized IrO2 anode electrocatalyst was prepared by a sulfite-complex route for application in a proton exchange membrane (PEM) water electrolyzer. The physicochemical properties of the IrO2 catalyst were studied by termogravimetryedifferential scanning calorimetry (TGeDSC), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The electrochemical activity of this catalyst for oxygen evolution was investigated in a single cell PEM electrolyzer consisting of a Pt/C cathode and a Nafion membrane. A current density of 1.26 A cm-2 was obtained at 1.8 V and a stable behavior during steady-state operation at 80 °C was recorded. The Tafel plots for the overall electrochemical process indicated a slope of about 80 mVdec-1 in a temperature range from 25 °C to 80 °C. The kinetic and ohmic activation energies for the electrochemical process were 70.46 kJ mol-1 and 13.45 kJ mol-1, respectively. A short stack (3 cells of 100 cm2 geometrical area) PEM electrolyzer was investigated by linear voltammetry, impedance spectroscopy and chrono-amperometric measurements. The amount of H2 produced was 80 l h-1 at 60 A under 330W of applied electrical power. The stack electrical efficiency at 60 A and 75 °C was 70% and 81% with respect to the low and high heating value of hydrogen, respectively.

9 páginas.- 1 tabla.- 18 figuras. Several graphite-based electrodes are investigated for vanadium flow battery applications. These materials are characterized both as-received and after chemical or electrochemical treatments in order to vary the content of oxygen functional groups on the electrode surface. The surface properties of the samples are investigated by X-ray photoelectron spectroscopy. Electrochemical performance is evaluated by cyclic voltammetry and electrochemical impedance spectroscopy measurements in a three electrode half-cell. The chemical treatment with HNO3 causes a cleaning of the electrode surface from adsorbed oxygen species or labile bonded functional groups in highly graphitic samples. Whereas, carbonaceous materials characterized by smaller graphitic domains or a higher degree of amorphous carbon show an increase of oxygen functional groups upon chemical and electrochemical pre-treatments. In both cases, an increase of oxygen species content on the surface above 5% causes a decrease of electrochemical performance for the redox battery determined by an increase of ohmic and charge transfer resistance Authors from CNR-ITAE acknowledge the financial support from “Ministero dello Sviluppo Economico – Accordo di Programma MSE-CNR per la Ricerca del Sistema elettrico Nazionale”. Peer reviewed