bluuebunny/crossref_metadata_2025 huggingface dataset:
Detailed modelling of a double fluidised bed steam gasifier processing woody biomass and solid recovered fuel mixtures
Authors: Palone Orlando , Palacios Aparicio Juan Diego , Vespasiano Domiziana , Nicolucci Edoardo , Colozzi Michele , Venturini Paolo , Rispoli Franco , Borello Domenico
Published: December 2024

Double fluidized bed gasification is based on the circulation of an inert bed between two reaction sections: the gasification reactor, where a solid feedstock, generally biomass. is converted into a syngas by steam or air oxidation; the combustor or riser, where residual char from the thermal decomposition of the feedstock is oxidized by air (in some cases with additional fuel) to provide the energy contribution for the gasification reactions and ensure autothermal operation of the system. In this work, detailed modelling of a dual fluidized bed steam gasification reactor is performed in Aspen Plus by incorporating: (1) gas, char and tar production during thermal decomposition of the feedstock according to experimental correlations developed and taken from the literature, (2) heterogeneous and homogeneous reaction kinetics in the gasifier bed and in the freeboard. The model has been validated by comparison with experimental results on different mixtures containing solid recovered fuels and woody biomass. The model is quite accurate in predicting the gas products composition for different feedstocks mixtures (root mean square error of 12% for CO, CO2, H2 and CH4) and enables coupling with different downstream liquid fuels synthesis processes (synthetic natural gas, methanol, dimethyl-ether, Fischer-Tropsch products etc.).
Energy transition pathways towards carbon neutrality: the 2035 Apulia case
Authors: Zagaria Lazzaro , Caramia Giovanni , Foglia Mario Massimo , Amirante Riccardo
Published: December 2024

Changing how society perceives and uses energy is essential, and a change in the way energy is produced is also needed. Europe is striving to become the first climate neutral continent in 2050: therefore, it is crucial to draw a pathway to achieve this result. In this paper different energy scenarios for 2035 for a southern Italian region are analysed. As the major goal, carbon emissions reduction must be at least half of the current, considering 2035 as a halfway point between current situation and carbon neutrality goal set for 2050. The aim of this work is to analyse the role of a major increase in energy production from either photovoltaics or wind, to achieve which option is the best to be chosen. Photovoltaics and wind are green but also intermittent energy technologies. Therefore, it is beyond doubt that the uncontrollable nature of sun and wind sources requires to store energy. Doubling the total energy production from wind and photovoltaics, results show different conditions in terms of energy storage required and investment and operation costs. The methodology used is numerical simulation of the Apulia case through EnergyPLAN software. Best conditions are achieved for higher energy production rate from wind, compared to current values. 50% emissions reduction goal is achieved for all analysed scenarios.
Three-dimensional simulation of a floating wind turbine platform
Authors: Caramia Giovanni , Fiore Andrea , Genualdo Marco , Palma Pietro De , Amirante Riccardo
Published: December 2024

As the need for renewable energy has grown in recent years, the possibility of creating and collecting deep-sea wind energy has become a research hotspot. Floating wind turbines need platforms to provide a stable working state and structural safety. This article focuses on the study of the dynamics of the deep-water semi-submersible floating platform OC4-DeepCwind. The open-source computational fluid dynamic toolbox OpenFOAM is used for comparative analysis of the floating structure motion response. In order to eliminate the influence of grid size and refinement level on the simulation results, a grid refinement study was conducted before detailed hydrodynamic discussions. In absence of wind, the dynamic response of the platform is studied under the influence of the impact with regular waves with different amplitudes. The effect of the presence of the tower supporting the wind turbine on the dynamics of the platform is investigated as well. Results show that the addition of the tower exerted a slight destabilising influence on the support’s dynamic behaviour, confirming its stability against different wave height. Finally, the model has demonstrated its efficacy as a highly valuable tool for the simulation of wind turbines on floating foundations.
On the design of a scaled rotor for a tethered tidal converter to deploy at sea
Authors: Gurnari L. , Filianoti P. , Coiro D. , Camporeale S. M.
Published: December 2024

Model scale testing is vital for developing technologies like tidal turbines. Reduced-scale tests follow numerical design and are cost-effective in controlled environments, allowing parameter adjustments. However, controlled tests face drawbacks, such as blockage effects and the inability to replicate real sea conditions. Sea trials, conducted in actual marine environments, offer realistic data and continuous collection, potentially being cost-effective despite environmental variability and complex data processing. This work aims to measure real sea effects, such as marine growth and stream turbulence, on fixed and moving parts, of a scaled model of GEMSTAR tidal stream energy converter, a twin rotors submerged tethered device, designed to tap tidal current energy. The planned model installation site is at the Renewable Marine Energy Laboratory, a natural facility located on the East coast of the Strait of Messina (southern Italy), characterized by tidal currents with a maximum speed of about 1.25 m/s. Due to the low stream speed, in order to get significant data, an up-scaling of the existing model rotor diameter has been necessary, and a specific new blade design has been performed, in order to lower the cut-in speed, increasing in this way the useful power production time of the model. The paper illustrates the different phases of model scale design.
Investigation on a thermal energy storage system to maximize the use of vessels’ waste heat in port and during hoteling operations
Authors: Brancato V. , Fotia A. , Palomba V. , La Rosa D. , Costa F. , Frazzica A.
Published: December 2024

Looking at International Maritime Organization (IMO) 2050 targets for shipping sector, that consist of reduction reenhouse gas (H) emissions from international shipping by at least 50% and carbon intensity by 70% (compared to 2018), it is clear that different low carbon technological solutions must be tackled to reduce vessels emissions in harbour and coastal areas. The combination of Waste Heat Recovery (WHR) on board, duly managed also thanks Thermal Energy Storage (TES) support and the promotion of zero carbon fuels (hydrogen) could be a suitable integration strategy.

The present study is focused on the investigation of the best technological solution to implement a TES system on vessels to support both the operation of a hydrogen storage tank based on metal hydrides, to provide H2 to the fuel cells installed on board, and the heating and cooling systems.

Starting from the identified boundary conditions, the work investigates both a latent heat TES system, and a sorption thermochemical TES to increase the utilization of on board WH resource.

In particular, commercial phase change materials (PCM), namely Croda Therm 53 and Croda Therm 60, were studied to be implemented in the latent heat storage system. Up to forty heating/cooling cycles were performed on the materials to verify their stability. As thermochemical solution, a sorption-based TES system was investigated.

Experimental analyses on composite sorbent based on sodium iodide (30Nal-S) were performed to verify if the composite sorbents are more stable that the pristine salts.
Efficiency assessment of integrated Atmospheric Water Generators (AWGs) using the Global Evaluation Index (GEI): a case study
Authors: Cattani Lucia , Magrini Anna , Figoni Roberto
Published: December 2024

Atmospheric water can represent a potential solution to address the global water scarcity issue affecting an increasing proportion of the population. Two of the main issues related to its production and use are represented by the energy consumption and the need of meaningful quantities of liquid extracted per day. They can be addressed through an integrated approach, which consists in employing a single process to achieve more than one useful effect, with the same energy consumption. In this perspective, in the last decade, advanced Atmospheric Water Generators (AWGs) have been developed. Such a kind of machines are based on a compression reverse cycle and, besides a considerable water production (up to thousands of litres per day) are capable to exploit all the useful effects of the said cycle, consuming about the same energy of the only water extraction. The global evaluation index (GEI) has been developed to provide a metric for the efficiency evaluation of integrated solutions. In the research literature there is a lack of examples of GEI application. The current paper aims to provide a first fulfilment of the research gap, providing a case study where the index is applied and discussed. In particular, the analysis concerns an integrated AWG connected to an electrolyser and a photovoltaic field for green hydrogen production. The GEI is employed to carry out a comparison between pre and post configuration of the plant. Results underline the index capability to provide an efficiency evaluation by means of a single number.
Numerical investigation of turbulent fuel jet diffusion and its influence on the auto-igniting diffusive flame development
Authors: Cravero Carlo , Lamberti Alessandro , Marsano Davide , Milanese Gabriele
Published: December 2024

Turbulent auto-igniting diffusion flames are common in combustion systems, where the mixing of the fuel jet with the outer oxidant flow is the fundamental mechanism for the flame ignition and development. The paper presents a critical analysis on the Reynolds-Averaged-Navier-Stokes (RANS) simulation of a methane-air flame, done with a two equations turbulence model, in comparison with detailed experimental data. In the first part, the non-reactive jet is simulated with the standard k − ε model and a modified version, obtained with motivated changes of the Cμ
and σk
constants. In the second part the reactive jet is simulated, introducing a consistent modification of the Cγ
constant, in the eddy dissipation concept (EDC) model. The comparison with experimental data confirms the validity of the proposed model and highlights the effect of the proper turbulent jet development on the mechanisms of the diffusive flame ignition and propagation.
Enhanced energy efficiency technologies in healthcare buildings: a case study of waste heat recovery from an optimized battery-integrated cogeneration system
Authors: Alfredo Gimelli , Raffaele Iossa , Karimi Ali
Published: December 2024

Healthcare buildings face significant challenges in enhancing energy efficiency. Combined, heat and power (CHP) plants integrated with battery energy storage systems (BESS) offer a promising solution by meeting electric, thermal and cooling demands using a single fossil primary energy source. Starting from an optimized battery-integrated cogeneration plant, a comparative analysis of two waste heat recovery technologies in a hospital building context has been conducted in this study. Specifically, an ammonia-water absorption, power, and cooling (APC) system and an organic Rankine cycle (ORC) plant are examined, both powered by the waste heat recovered from exhaust gases of the natural gas internal combustion engine, operating in a cogenerative configuration. A control strategy is implemented to enhance the efficiency of the integrated systems, prioritizing either cooling or electric power production based on hourly demand within the hospital. The results highlight the integration of waste heat recovery technologies inside the optimized battery-integrated cogeneration is capable to reach a 20.1% and 18.82% in fossil primary energy saving (PES), respectively with the ORC and APC systems. However, the higher investment cost brings the simple payback (SPB) period of the configuration with the ORC plant to 3.5 years, compared to 3.3 years of the solution with the APC plant. The study shows the benefits of incorporating waste heat recovery technologies into cogeneration systems with energy storage system, providing valuable guidance for developing economically viable and eco-friendly solutions for managing energy in healthcare buildings.
Piecewise-linear MILP optimization for energy system design onboard hybrid ships
Authors: Vasylyev Andriy , Passalacqua Matteo , Mantelli Luca , Rivarolo Massimo , Sorce Alessandro
Published: December 2024

In recent decades the share of GHG (Green House Gases) such as carbon dioxide (CO2), and local pollutants as carbon monoxide (CO), nitrogen oxides (NOx), and sulphur oxides (SOx) produced by shipping has significantly increased. In the case of CO2, the IMO (International Maritime Organization) has estimated that emissions will increase by a range of 90-130% in 2050 as compared to 2008. In this scope, penetration of new technologies such as Battery Energy Storage Systems (BES) can reduce the share of emissions, giving more flexibility to the ship’s system. In this work, an optimization algorithm based on Mixed-Integer-Linear-Programming (MILP) approach has been developed to define the best environmentally sustainable technology mix to be installed on board. The model is based on Demand-Driven optimization, where the main goal is to satisfy electrical and thermal energy demand, which is achieved by using linear constraints. The objective function is defined to minimize on-board energy production costs considering the CAPEX and OPEX of each technology, choosing the best technology mix and giving the schedule of working conditions for each installed technology. The non linearity of the components’ characteristic curves is tackled through piecewise-linearization approach. In this way, the algorithm can optimize the real operating conditions for technologies with higher accuracy of partial load conditions. The case study is based on real energy demand profiles of a cruise ship sailing between Stockholm and the island of Åland, in the Baltic Sea.
Energy Efficiency of the Office Buildings in Italy: Insights for the European Taxonomy.
Authors: Aquino Andrea , Bassetti Marco , Grasso Edoardo , Martini Fabrizio , Salvio e Marcello
Published: December 2024

Sustainable investments have led the Italian real estate market over recent years. Large enterprises invest in renovating their building stocks to optimize costs, respond to institutional pressures, and enhance their Environmental, Social, and Governance (ESG) scores. The ESG criteria orient the preferences of today’s investors by measuring a company’s sustainability and profitability; however, the ESG rating systems lack transparency, exposing investors to misleading sustainable initiatives (greenwashing) and risks of financial losses. The EU Taxonomy for Sustainable Activities (EU Regulation 2020/852) defines technical thresholds for sustainability that support investors in making informed decisions. In the building sector, the Taxonomy distinguishes (i) new building construction and (ii) retrofitting existing buildings; the latter is sustainable if it reduces the existing building’s primary energy use by 30% compared to ante-opera or follows the retrofitting guidelines established by the EU directive 2010/31. This work aims to estimate the potential for energy savings and CO2 reduction of the Italian office building stock according to the Taxonomy guidelines. The Energy Efficiency Directive 2012/27/EU (EED) establishes a legislative framework for achieving the European energy efficiency targets. Article 8 of the EED introduced the obligation for large enterprises to submit an energy audit of their production sites every four years, starting from December 2015, and the Italian National Agency for New Technologies, Energy, and the Sustainable Economic Development (ENEA) collects and reviews such energy audits. This study analyzes the energy audits of office buildings submitted by large enterprises in the insurance and banking sectors last year. The database associates the technical features of each building with the main characteristics of its location (e.g., the climate and urban landscape) and energy use. Data show the benefits of retrofitting office building portfolios following the Taxonomy, showing a reduction of energy use and CO2 emissions up to 20% from the current state. Electrification of heating loads is particularly effective in cold climates. At the same time, intense reconstruction produces the highest benefits, but it needs careful resource allocation, driven by cost-benefit analysis.
Thermally-integrated CO2 cycles for MW-scale power generation and storage
Authors: Traverso A. , Maccarini S. , Shamsi S. S. M. , Barberis S. , Persico G. , Romei A. , Kamali K. , Fiaschi D. , Gigliotti F.
Published: December 2024

In an energy scenario driven by Renewable Energy Sources (RES), where more and more bulky quantities of RES should be introduced on the grid, the role of energy storage systems is crucial. Further to already available electric storage technologies (mostly based on batteries), it will be mandatory to have grid flexible large scale energy storages able to operate ramp-up/down with large capacity, whose behaviour/management should be as much similar as possible to traditional power plants (also to guarantee specific grid services like grid frequency regulation via rotating inertia etc.) which are currently used to instantaneously regulate the grid. At this purpose, Pumped Thermal Energy Storage (PTES) offers GWh scale storage without geographical constraints, at reasonable costs, and implementing power and heat pump cycles integrated with thermal energy storage (TES) solutions. The peculiar features of supercritical CO2 (sCO2) make it the ideal candidate to act as working fluid for large scale PTES applications. sCO2 cycles are indeed fully compatible with the temperature range of TES hot storage sources and sCO2 has already been used in commercial HP solutions (even targeting high temperature HPs). In addition, sCO2 allows energy storage to embody a compact design as well, making the whole PTES footprint smaller compared to technologies based on other working fluids. Nevertheless, sCO2 based PTES solutions cannot achieve significant Round Trip Efficiency (RTE): a possible solution to such a limitation is represented by the exploitation of freely available heat sources (like thermal RES or waste heat), which could increase the COP of the charging cycle and, at the end, the electrical-based RTE, therefore in the so-called Thermally Integrated Pumped Thermal Energy Storage (TI-PTES). In the framework of the PRIN 2022 project ECO-SEARCHERS, specific cycle layouts of interest are studied and compared on a thermodynamic basis: the most promising solution is presented in this paper. Finally, the test rig that will be used for laboratory-scale validation of a small size radial bladeless turbine is described, providing a first glance to the technical challenges in realizing and managing sCO2 cycles in practice.
Comparative analysis of a Packed-Bed Thermal Energy Storage operating with pure gases and nanoaerosol.
Authors: Cascetta Mario , Casti Efisio , Cau Giorgio , Petrollese Mario
Published: December 2024

This paper investigates the thermal performance of a packed-bed thermal energy storage (TES) system and the impact of introducing nanoparticles into the working fluid. A one-dimensional transient numerical model based on Local Thermal Non-Equilibrium (LTNE) principle is validated against experimental data. Key parameters, such as temperature distribution and thermocline formation, show good agreement between numerical and experimental results with an average RMSE on the thermocline profile equal to 0.96 K during the charging phase, and 2.74 K during the discharging phase. The effect of adding nanoparticles to the working fluid are then examined. Nanoparticles enhance the fluid’s effective thermal conductivity, improving heat transfer. Numerical simulations indicate that nanoparticle concentration increases the mass flow rate but decreases the volumetric flow rate, resulting in reduced pressure losses within the bed. Higher nanoparticle concentrations significantly enhance the convective heat transfer coefficient. Overall, introducing nanoparticles improves the TES system’s thermal performance without significantly altering its energy storage capacity. The validated model helps optimize TES system design, balancing enhanced thermal properties and increased fluid density.
0D physical model for the charging phase of shell-and-tube Latent Heat Thermal Storage
Authors: Ceglie Vito , Anaclerio Fabio , Camporeale Sergio Mario , Milozzi Adio , Nicolini Daniele , Fornarelli Francesco
Published: December 2024

The transition to sustainable energy raises many issues that need to be addressed in order to develop reliable energy production infrastructures. Among these challenges, the mismatch between primary energy sources and energy loads stands out as a significant barrier to the widespread adoption of renewable technologies. Efficient energy storage solutions are crucial to mitigate this mismatch and facilitate the integration of renewable energy sources into existing grids. In this study, to evaluate the performance of this component within any plant, we focus on developing a simple yet effective model for predicting the behavior of shell-and-tube latent heat thermal energy storage (LHTES) systems limiting the analysis to the melting phase. LHTES systems offer promising potential due to their high energy density and ability to store thermal energy at a slightly constant temperature. However, their performance depends on various factors such as material properties, geometry and operating conditions, which require accurate predictive models for optimization and design purposes. Our proposed model uses fundamental principles of heat transfer and phase change phenomena to simulate the behavior of LHTES systems during the melting phase. By considering factors such as heat transfer coefficients, phase change kinetics and thermal properties of the storage medium, our model aims to provide insight into the thermal performance and efficiency of shell-and-tube LHTES configurations. Through validation against experimental data and numerical simulations, we demonstrate the effectiveness of our model in accurately predicting key performance metrics such as charge rates, temperature distribution within the storage medium, and overall energy storage efficiency. Its simplicity and computational efficiency make it suitable for practical applications, enabling engineers and designers to optimize LHTES systems for specific operating conditions and integration scenarios.
Enhancing tribological performance of External Gear Pumps through CFD Analysis of Textured Surfaces and gear Edge Chamfering
Authors: Casoli Paolo , Masoud Hatami Garousi , Vescovini Carlo Maria
Published: December 2024

External gear pumps (EGP) have become more and more common in a variety of industrial fields because of their advantageous cost-performance ratio, high efficiency, small design, and reliability. EGP are conceptually simple machines, but the design is often difficult, especially to ensure good performance at high working pressures. Among the internal components of EGP, the lateral plates are two important elements that strongly affect the performance of the machine. In this work, computational fluid dynamics (CFD) simulations are performed to investigate the effects of plate with textured surfaces and gear with chamfered edges on the bearing capacity. The simulations of the fluid flow in the oil gap between the gear tooth and the side bushing consider the correct pressure distribution at the inlet and outlet of the meatus, involving in the simulation also the portion of oil in the tooth space volumes surrounding the tooth.
Innovative and self-adaptive energy recovery system in hydraulic cylinders for cyclic operations
Authors: Romagnuolo Luca , Frosina Emma , Hieronymis Carlo Rozzi de , Bordini Giorgio , Senatore Adolfo
Published: December 2024

Conventional hydraulic actuation supply and control systems usually work with a very high energy loss, especially in the field of off-road machinery. In particular, during the lowering phase of a boom of a hydraulic excavator, energy dissipated through lamination in thermal heat is a consistent fraction of the energy required for operating the working cycle. In this paper, an innovative system is presented that can recover a significant fraction of this energy, to make it available for the next working cycle, which adapts the level of energy recovery in order to maximise the overall efficiency.

In the presented system, the conventional hydraulic actuators that operate the boom of a large size hydraulic excavator are replaced with three-chamber actuators, in which the third chamber, obtained inside the cylinder rod, is connected to a secondary hydraulic circuit that involves a series of accumulators: the compression and the subsequent expansion of the amount of gas inside the accumulator allows to, respectively, store the maximum possible recoverable energy, during load lowering phase in the first cycle and deploy it in the next cycle. The initial gas pressure inside the accumulator is set accordingly to the maximum amount of recoverable energy during the cyclic operation, and can be easily changed via a low-displacement auxiliary pump and a feedback control mechanism, without the need of stopping the machine to vary the amount of inert gas inside the accumulators.

A hydraulic manifold has been designed to manage and regulate the flow rates of both the main and the secondary circuits. Pressure losses inside the manifold have been evaluated through CFD analysis, performed in SimericsMP+ environment. The whole system has then been simulated as a lumped parameter model developed in Simcenter Amesim ©. Results from the simulation of the proposed system show that, on a working cycle of 20 s, only 25% of the hydraulic energy required for the conventional system is needed to operate the boom in the proposed configuration.

This method can be easily extended to several hydraulic actuators that realise frequent height changes of the load.
An Electrochemical Impedance Spectroscopy (EIS) analysis of a reversible Solid Oxide Cell (rSOC) for its electrochemical characterisation
Authors: Mennilli Francesca , Giannetti Lorenzo , Ferrario Andrea Monforti , Rossi Mosè , Comodi Gabriele , Pietra Massimiliano Della
Published: December 2024

The Electrochemical Impedance Spectroscopy (EIS) technique is widely used to characterise electrochemical reaction mechanisms. This technique identifies the main phenomena occurring in an electrochemical device. When dealing with Solid Oxide Electrolysers (SOECs) and Fuel Cells (SOFCs), button cells are generally used for improving their structure, choosing the right electrode materials, and testing manufacturing processes. EIS techniques are then employed to evaluate their performance under different operating conditions. However, larger industrial-sized cells are used for being operated in real test environments, meaning that a larger number of experimental tests on ever-increasing cell area are required to evaluate and assess their performance properly. In such a context, this work aims to cover this research gap by providing EIS spectra as preliminary results of an experimental campaign carried out on a 5x5 cm
2 rSOC operating at different conditions in terms of temperature and gas composition. In SOEC mode, an increase in the water content at the fuel electrode leads to unstable conditions and an increase in the polarisation and ohmic resistances. In SOFC mode, a decrease in the hydrogen content at the fuel electrode leads to a maximum increase of the polarisation resistance of 34.17%, while a decrease in the oxygen content at the air electrode leads the system to highly unstable conditions. In both cases, the cell temperature variation leads to a maximum reduction in the ohmic resistance of 12 and 3.8% in SOEC and SOFC modes, respectively.
A MATLAB/Simulink model of a parallel hybrid PEMFC/battery powertrain for passenger cars
Authors: Parmiggiani D. , Antetomaso C. , Martoccia L. , Merola S. , d’Adamo A.
Published: December 2024

The transition towards sustainable transportation solutions needs the development of efficient and environmentally friendly propulsion systems. Among these, Proton Exchange Membrane Fuel Cells (PEMFCs) seem to be a promising solution for sustainable powertrain design. This study presents the development of a MATLAB/Simulink model for a parallel hybrid FC/battery system representative of a passenger car, including all the auxiliary components and sub-systems. The model incorporates electrochemical, heat transfer, and fluid dynamic processes to accurately simulate the dynamic PEMFC stack and system behaviour. By implementing user-defined initial and boundary conditions, the model offers flexibility in simulating real-world scenarios, allowing the investigation of system performance under different environmental and dynamic driving conditions, as prescribed by the latest homologation protocols. Additionally, it accounts for the membrane degradation, which is a critical aspect affecting long-term durability, performance, and efficiency. Furthermore, a Graphic User Interface (GUI) has been developed to simplify the input of the main parameters, embedding the model in a user-friendly yet comprehensive tool designed for students, researchers, and engineers to evaluate the realizability of these efficient technologies. The intrinsic adaptability to model any FC/battery power system under a generic time-varying load constitutes an additional valuable point of the presented study to enable engineering progress, advancing the energy transition via sustainable powertrain solutions.
Retrofitting of a hybrid propulsion shunting locomotive equipped with Fuel Cell and Metal Hydrides storage
Authors: Barberis Stefano , Rivarolo Massimo , Magistri Loredana
Published: December 2024

The use of hydrogen as an energy carrier is more and more interesting in the current energy scenario due to the possibility of utilizing electrolysis as a large-scale energy storage solution for renewable energy plants and its versatility as a fuel in various applications, both stationary (hard-to-abate industries) and in transports. However, the use of hydrogen still presents technological challenges, particularly concerning its storage and transportation. The use of metal hydrides (MH) intermetallic compounds to store the gas helps to reduce the hazards and technological complexities that other storage systems (such as high-pressure compressed hydrogen or liquid hydrogen) may entail, allowing low pressure storage.

These compounds are capable of absorbing hydrogen atoms into their interstitial lattice, releasing them once heated with a sufficient amount of heat.

This study assesses the possibility of using (instead of a compressed hydrogen storage system) a metal hydride system onboard of a shunting locomotive (to be used in ports and interports) as part of a retrofitting process aimed at converting the locomotive itself to hydrogen, equipping it with a PEMFC driven power-train whose waste heat could be valorised to drive the management of MH discharge. Based on the locomotive’s characteristics and constraints (weights and size, amount of fuel to be stored onboard according to its mission profile), the amount of hydrogen that could be installed on the vehicle was assessed, looking at the feasibility of storing H2 on board via MH due to space and weight constraints.

In this analysis, three different metallic compounds (LaNi5, TiFe, TiMn1.5) widely used in the field of metal hydrides, and various tank designs (which allow different heat exchange between the MH and the heat transfer fluid coming from the PEMFC) have been considered in order. The different tank layouts were compared to analyse the thermal management of the metal hydride discharge process through the recovery of waste heat from the locomotive’s power-train fuel cell, thus targeting solutions for the final MH tank sizing and design.
Evaluation of water/energy intensity of green hydrogen production plants in Africa scenario
Authors: Rivarolo Massimo , Barberis Stefano , Portesine Aurora , Massardo Aristide F.
Published: December 2024

The recent environmental concerns due to CO2 emissions continuous growth and the contemporary increase in fossil fuel prices on international markets are two important factors that are moving the interest towards green and carbon free fuels. In this sense, green hydrogen production from electrolysis is a very promising option as a way to store electrical energy from renewable energy sources (RES) as fuel. However, two inputs are necessary: electrical energy and water. Whereas in EU scenario, electrical energy costs are the ones which affect more the feasibility, in Africa scenario, the availability of RES, in particular solar, is higher in many Countries, allowing for lower energy costs. Green hydrogen production can represent an important resource for microgrids and remote local communities, where the electrical and gas grids are not well developed. However, in this scenario, the large amount of high purity demineralized water required for the process may represent a critical aspect that must be considered. In this study, three different microgrids located in Africa (Kenya, Mali and South Africa) are analysed, considering solar PV installation, three different water intake options (ground water, surface water and seawater), and the impact of the water purification process on the whole plant from both the energy and the economic standpoints. The analysis is performed for the three scenarios, assuming the same electrolyser size (1 MW), considering PEM commercial systems and evaluating the feasibility in the three scenarios, optimizing the PV plant size (range 1-10 MW) to minimize H2 production cost. For the chosen configurations, the water-energy-food nexus is investigated, as both the water intensity and the required area (not available for agriculture purpose) are evaluated.
Feasibility study and optimal sizing of H2 storage and PEM fuel cells onboard ships
Authors: Rivarolo M. , Raggio M. , Montagna G.N. , Barberis S.
Published: December 2024

The International Maritime Organization (IMO) established a challenging global strategy in 2023 to reduce greenhouse gas (GHG) emissions from international shipping by 70% by 2040. Achieving these targets necessitates radical actions, including the use of carbon free fuels and hybrid-alternative propulsion systems. The NEREHYDES (Novel hEat REcovery solutions on board of fuel cell equipped vessels for metal HYDridES storage optimal management) national research project aims to optimize the design and management of a hybrid system with hydrogen fuelled Proton Exchange Membrane Fuel Cells (PEMFC) and diesel Internal Combustion Engines (ICE) on board short-travel ferries for zero-emission operation in coastal and harbour areas. The new PEMFC - MH system is designed to operate mostly in harbour, while the traditional ICE operates during navigation in open sea. The study consists of a pre-feasibility analysis for retrofitting an existing ferry by including a PEMFC system. For the hydrogen storage required for the considered travel distances, metal hydrides (MH) storage is employed, allowing for the H2 storage at low pressure and close to room temperature.

The study is carried out considering the requirements of two real vessels operating in Sicily (Italy) and their daily travelling routes, aiming to find the optimal sizes for both PEMFC and MH systems, minimizing the overall costs and volumes to properly fit this additional system into the existing ferries. Finally, a preliminary techno-economic and environmental assessment is performed to compare the different solutions.
Feasibility Analysis of Green Hydrogen Production Systems for Decarbonized Heating Applications: A Dynamic Modelling Approach on Simulink
Authors: Caravelli Alessandro , Pozzessere Adriano , Veroli Mario Di , Cedola Luca , Verones Sara , Borello Domenico
Published: December 2024

This paper presents a dynamic model of a hydrogen production system aimed at residential heating applications, utilizing MATLAB® and Simulink® softwares. The global model is divided into different macro-sections, each covering a specific role in the hydrogen production and distribution process. These include the photovoltaic field, the electrolyzer, the short-term and long-term storage sections and the end-users. The graphical interface of Simulink is employed, with particular reliance placed on the Simscape library for the modelling and simulation of physical lines. The control logic that governs the operation of the system is implemented using the Simulink tool Stateflow, thereby ensuring efficient management of hydrogen production, storage, and distribution phases. Two distinct scenarios are analysed, each considering different weather data, thermal demand distribution and infrastructure configuration. For each Scenario, simulation results provided a detailed trend of PV power production and electrolyser power consumption, hydrogen production, variations in storage tank pressures, as well as power consumption by auxiliary systems. A comparative analysis with fossil fuel sources is then assessed by calculating the overall reduction of CO2 emissions due to green hydrogen production. In conclusion, this paper provides a comprehensive framework for modelling, simulating, and evaluating green hydrogen production systems, offering insights into their potential as sustainable energy solutions for residential heating decarbonization.
Hydrogen and Natural Gas in Pipeline Networks: A Comparative Energy Analysis
Authors: Cava Carmine , Pozzessere Adriano , Caravelli Alessandro , Borello Domenico
Published: December 2024

In this study, a Simscape model for the transmission and distribution pipeline network of natural gas, hydrogen blended into natural gas and pure hydrogen, is developed. The transmission consists of a 250 km pipelines with a diameter of 48 in and two gas compression stations. The distribution network serves six end users. Two simulations are conducted for each gas: the first maintaining equal operational pressure in the transmission pipeline, while the second ensuring equal energy content at the final users by modifying the operational pressure. A comparative energy analysis is carried out to assess the gas mass flow rate, the thermal power delivered, the mechanical power required by compressors and the pressure losses along the pipeline.
Optimizing Hybrid Electric Microcar Design: A Simulation-Based Approach to Fuel-Cell Powertrains Analysis
Authors: Bartolucci Lorenzo , Cennamo Edoardo , Cordiner Stefano , Donnini Marco , Mulone Vincenzo
Published: December 2024

The pressing need to reduce emissions and pollutants requires a significant diversification of mobility solutions and energy sources used to this aim. Light quadricycles with electric powertrains are increasingly recognized in research and industrial sectors as viable alternatives for achieving urban sustainable mobility solutions. Their lightweight design, compact dimensions, simplified prototyping and manufacturing processes, high efficiency, and lower emissions across the entire life cycle contribute to their growing importance.

In line with this trend, integrating a hydrogen fuel cells stack with a battery pack is a promising powertrain solution, leveraging both technologies’ strengths. However, the design and development of such hybrid systems necessitate advanced methodologies that can address the problem of significant prototyping costs and time commitments while still ensuring optimal configurations. The availability of detailed simulation tools integrated with hardware components (vehicle simulation platforms) plays a crucial role in this endeavor, enabling insights on local phenomena which otherwise would be neglected, as such the purge phase, strongly impacting on the global consumption. These test platforms encompass all the main subsystems to account for all the vehicle demands while ensuring very good reliability for the predictions of performance and allowing the validation of the components. This enables the possibility of testing the vehicle under a wide set of operating conditions (e.g., weather conditions and driving cycles) within a simulated environment, thus reducing the costs related to the component sizing issues. In this context, the work presented in this paper, develops the fuel cell stack sizing analysis of a hybrid electric microcar, proposing a methodological approach for the powertrain design process.

A detailed simulation platform is introduced for a hybrid electric microcar. The two energy sources, namely the Li-ion battery pack and the fuel cell stack, have been experimentally characterized and implemented into the model, also considering the experimental performances of the balance of plant elements as of the DC-DC converter.

A linear scale-up method is implemented on the fuel cell stack to consider different configurations, and a deep analysis of the hydrogen consumption, comprising the scale-up of the purge phase, is presented, proposing two different approaches to the problem. From a technological standpoint, different results regarding the choice of fuel cell size have been found. As an example, the role of purging and its relationship with the size of the fuel cell stack may lead to a 14 % increase in the vehicle’s estimated range with respect to the baseline. Cost analyses are then needed to reach a trade-off between the costs and the technological standpoints.
A Novel Hydrogen-Nitrogen Heat Exchanger For Aeronautical Applications
Authors: Domenico Vincenzo Di , Tamburrano Paolo , Sciatti Francesco , Distaso Elia , Foglia Mario Massimo , Amirante Riccardo
Published: December 2024

Renewable fuels are playing an increasingly central role in shaping today’s energy landscape, and within the aviation sector there is a remarkable drive to research and develop engines that harness the potential of these sustainable resources. Looking specifically at hydrogen, a fuel with immense promise, there is a critical need to maximize storage capacity, prompting consideration of storing it in a liquid state. However, before this stored hydrogen can be used for combustion, it must undergo an important process of vaporization. To address this challenge, this paper presents an innovative heat exchanger model. In this model, nitrogen is used as a medium to transfer heat energy to the stored hydrogen, allowing it to be converted to a gaseous state and making it easily usable in the combustion chamber. In addition, to provide a comprehensive understanding of the thermodynamic processes involved, a detailed and thorough thermodynamic model is presented that properly captures the exchange of heat flow rates. Moreover, the pipe-in-pipe architecture is adopted, and the assumed geometrical data are validated numerically.
Feasibility study and sizing of TES coupled with Metal Hydrides storage for H2 fuelled ships
Authors: Barberis Stefano , Rivarolo Massimo
Published: December 2024

The International Maritime Organization (IMO) established a challenging global strategy in 2023 to reduce greenhouse gas (GHG) emissions from international shipping by 70% by 2040. Achieving these targets necessitates radical actions, including the use of carbon free fuels and hybrid-alternative propulsion systems. The NEREHYDES (Novel hEat REcovery solutions on board of fuel cell equipped vessels for metal HYDridES storage optimal management) national research project aims to optimize the design and management of a hybrid system with hydrogen fuelled Proton Exchange Membrane Fuel Cells (PEMFC) and diesel Internal Combustion Engines (ICE) on board short-travel ferries for zero-emission operation in coastal and harbour areas. Hydrogen would be stored on board via metal hydrides storage (MH), allowing for the H2 storage at low pressure and close to room temperature.. The new PEMFC - MH system is designed to operate mostly in harbour, while the traditional ICE operates during navigation in open sea. In this way, Waste heat produced by the engine could be stored on board of TES to be then used to properly manage the metal hydrides discharging once in harbour to properly operate the PEMFC: once the PEMFC will be fully operative, the waste heat produced by the FC could be exploited in order to minimize TES size.

The study consists of a pre-feasibility analysis for sizing the TES on board based on above mentioned operational strategy of the integrated system (ICE-TES-MH-PEMFC) towards the minimization of the volumes. At this purpose two different type of TES (sensible heat with hot water and latent heat with identified PCM suitable to manage the MH discharge) will be compared, analysing the volume and cost needs for both of them.

The study is carried out considering the requirements of a real vessel operating in Stretto di Messina - Sicily (Italy) and its daily travelling routes, aiming to compare the sizing architectures of the integrated system via a heat transfer modelling tool developed by the Thermochemical Power Group (TPG) at the University of Genoa.
Hydrogen Valleys for Local Energy System Decarbonization: An Assessment of the Environmental and Economic Aspects
Authors: Bekele Endeshaw , Ciancio Alessandro , Massulli Axel Riccardo , Santoli Livio de
Published: December 2024

The necessity to address the adverse impact of global climate change has led to the widespread adoption of clean energy and the prioritization of decarbonising “hard-to-abate” sectors. This work aims to investigate the environmental and economic aspects of a Hydrogen Valley to facilitate the decarbonization of local energy systems and to integrate the hydrogen value chain across various stages from production to utilization. The southern Italian province of Taranto was selected for the case study, and the energy system is modelled in EnergyPLAN software considering the ‘business as usual’ scenario. The levelized cost of hydrogen (LCOH) is calculated, and its variation with the installation cost of the electrolyser is analysed. The result shows that the carbon emissions and total annual costs of the business-as-usual scenario are 4.098 Mt of CO2 emissions and 0.98 billion euros, respectively. The levelized cost of hydrogen is found to be 4.09 €/kg. A 71.4% reduction in capital expenditure (CAPEX) will decrease the levelized cost of hydrogen (LCOH) to 2.78 €/kg, highlighting the crucial role of cost reductions in electrolyser technologies for achieving a lower levelized cost of hydrogen.