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Unmanned aerial vehicles (UAVs) have recently received great interest due to their great potential in both military and civil applications [1]-[4]. Anyway, testing and construction of UAVs is expensive and time consuming. In this context, the simulation approach can help to reduce the cost both design and tests. In this paper, the authors used COMSOL Multiphysics 5.1 to design a UAV's pod equipped with a Solid Oxide Fuel Cell (SOFCs). The study was developed in the framework of the European project SUAV (Microtubular Solid Oxide Fuel Cell Power System development and integration into a Mini-UAV). The stack's maximum power is 200 W and is fed by propane. Thanks to his energy density, using propane as fuel permits to store more energy than fuel cell fed by hydrogen. The aim of study was to calculate the temperature distributions inside the pod having information about the air intakes' size. An simple experimental test was carried out to validate the simulation. The test's set up consists of a PVC tube where the SOFC stack is located inside as showed in figure 1. In front of PVC tube was located a mask with variable surface area (from 5% to 75% open). Experimental test had permitted to evaluate the influence of outlet size on temperature distribution. The inlet air was controlled through a mass flow rate according to the internal temperature and pressure transmitters were used to measure the pressure drop along the tube. In early study, COMSOL Multiphysics simulation will be validate through experimental data and will used to evaluate new air intake configuration (different position and size) as showed in fig.2 . In the following figure, the geometry implemented in COMSOL and preliminary fluid dynamic results are reported. A turbulent approach was used to solve the problem. Early results showed that pressure drop and velocity field are in accordance with experimental tests. The next steps will be the implementation of model with "heat transfer in fluid" physic to know the distribution of temperature in the domain for a complete model validation model. [1] Frost&Sullivan, 2007, "Study Analysing the Current Activities in the Field of UAV," European Commission - Enterprise and Industry Directorate-General. [2] Peng K, Dong M, Chen Ben M, Cai G, Lum KY, Lee TH. Design and implementation of an autonomous flight control law for a UAV helicopter. In: Proceedings of the 26th Chinese control conference, Zhangjiajie, Hunan, China, vol. 6, 2007. p. 662-7. [3] S. Saripalli, J.F. Montgomery, G.S. Sukhatme Visually-guided landing of an unmanned aerial vehicle IEEE Trans Robot Automat, 19 (2003), pp. 371-381. [4] Cox, T. H., Nagy, C. J., Skoog, M. A., Somers, I. A., and Warner, R., 2004, "A Report Overview of the Civil UAV Capability Assessment," NASA.

The expression "Hydrogen Economy" is used to indicate the role of hydrogen in the energy future scenario. Interest in hydrogen, as an energy carrier, has been growing in the recent years due to heightening of air pollution in the world. Hydrogen is a clean and flexible energy carrier that can be used to provide both power and heat across all end-use sectors. Vehicles and stationary power generation feed by hydrogen are local zero-emission technologies. Hydrogen can be produced from both traditional fossil fuel and carbon-free energy sources, used to store energy and to provide response management to electricity grid. Today only 4% of hydrogen is produced from electrolysis, other lower-cost methods are preferred, such as steam reforming of natural gas or refinery gas. However, in the next future, the Renewable Energy Sources (RES) will take up an important portion of electric energy produced. In this context, the energy storage is expected to play a key role in the future "Smart Grid". The future energy storage technologies should be more flexible and able to balance the grid, ensuring stability and security. Large scale deployment of variable renewable source (primary wind and solar energy) will be required to store energy to avoid the RES curtailment. Electrolysis is considered as the cleanest way to produce hydrogen using RES and has (along with other storage technologies) the potential as "energy storage" in this sector. The main advantages of PEM electrolysis over the alkaline are related to greater safety and reliability because no caustic electrolyte is used. Besides, the possibility to operating at high differential pressure across the membrane avoids the oxygen compression. PEM electrolysis has faster ion transportation than alkaline due to the solid and thin membrane. In fact, liquid electrolyte has more inertia in transportation of ions (K. Rajeshwar et al 2008). This aspect is particularly important when an electrolyser operates under fluctuating conditions.

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14 Figuras., Various Pt-based materials (unsupported Pt, PtRu, PtCo) were investigated as catalysts for recombining hydrogen and oxygen back into water. The recombination performance correlated well with the surface Pt metallic state. Alloying cobalt to platinum was observed to produce an electron transfer favouring the occurrence of a large fraction of the Pt metallic state on the catalyst surface. Unsupported PtCo showed both excellent recombination performance and dynamic behaviour. In a packed bed catalytic reactor, when hydrogen was fed at 4% vol. in the oxygen stream (flammability limit), 99.5% of the total H2 content was immediately converted to water in the presence of PtCo thus avoiding safety issues. The PtCo catalyst was thus integrated in the anode of the membrane-electrode assembly of a polymer electrolyte membrane electrolysis cell. This catalyst showed good capability to reduce the concentration of hydrogen in the oxygen stream under differential pressure operation (1–20 bar), in the presence of a thin (90 μm) Aquivion® membrane. The modified system showed lower hydrogen concentration in the oxygen flow than electrolysis cells based on state-of-the-art thick polymer electrolyte membranes and allowed to expand the minimum current density load down to 0.15 A cm−2. This was mainly due to the electrochemical oxidation of permeated H2 to protons that were transported back to the cathode. The electrolysis cell equipped with a dual layer PtCo/IrRuOx oxidation catalyst achieved a high operating current density (3 A cm−2) as requested to decrease the system capital costs, under high efficiency conditions (about 77% efficiency at 55 °C and 20 bar). Moreover, the electrolysis system showed reduced probability to reach the flammability limit under both high differential pressure (20 bar) and partial load operation (5%), as needed to properly address grid-balancing service., CNR-ITAE authors acknowledge the financial support from the NEPTUNE project. This project has received funding from Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 779540. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme and Hydrogen Europe and Hydrogen Europe Research. The authors also thank Solvay Specialty Polymers for supplying the membrane and the ionomer, ITM Power (UK) for supplying the high-pressure single cell test fixture and Mr. Giuseppe Monforte for the XPS analysis.

The Aeolian archipelago is made up of seven main islands situated in the Tyrrhenian sea (Sicily Italy). They represent a suitable scenario for the development of a sustainable energy production system, that could easily be reproduced on other Mediterranean Islands. The fact that these islands depend on the mainland for energy supplies and the high cost of bringing fuel in tanker boats are factors that should strongly encourage the use of renewable energy source technologies. Taking into account the European Commission guidelines, this paper sets out to evaluate potential energy production using photovoltaic and small scale wind power, in order to verify their contribution to overall estimated energy requirements. The estimate of energy productivity was preceded by a study concerning the management measures in force in the Aeolian Islands in order to formulate technical hypotheses in accordance with natural and cultural values protection. The homogeneity of climatic conditions on the seven islands and the similarity of their economies allowed to focus the analysis on the island of Salina. In this way, a whole year's productivity was calculated, with particular attention to the period June – September, when the arrival of tourists brings about a surge in energy consumption.