bluuebunny/crossref_metadata_2025_split huggingface dataset:
Process Design and Techno-Economic Assessment of biogenic CO2 Hydrogenation-to-Methanol with innovative catalyst
Authors: Lombardelli G , Consonni S , Conversano A , Mureddu M , Pettinau A , Gatti M 
Published: December 2022

Abstract
A small-scale 10 ton per day methanol (MeOH) synthesis plant, from CO2 and hydrogen, is designed and simulated with Aspen Plus and a techno-economic analysis is conducted. The e-fuel (MeOH) is produced in a conventional fixed bed reactor featuring an innovative Cu/Zn/Al/Zr catalyst, converting biogenic CO2 from a biogas upgrading plant with H2 produced by a grid powered PEM electrolyzer. The process is thermally autonomous as a result of heat integration and combustion of purged unconverted reactants. A sensitivity analysis is carried out in order to evaluate and compare the impact of the different technical (purge fraction, Gas Hourly Space Velocity and Pressure of the methanol synthesis) and economic parameters (Capital Charge Factor, electricity and H2 cost) on the Levelized Cost Of Methanol (LCOM). Results show that, although the energy efficiency is greater (47.4 % electricity to methanol conversion) in the scenario with “self-sufficiency” in which all the net heat required by the process is provided by off-gas streams, the case with the highest profitability is the one with maximum methanol yield and, therefore, minimum purge and non-zero thermal energy import (provided by a biogas boiler). The best case scenario features a LCOM equal to 1,361 €/tonMeOH, with a GHSV of 7,500 h−1 and synthesis reactor operating at 70 bar, 250 °C. H2 production cost is the key variable and shall be reduced from the base case value of 5.8 €/kgH2 to 1.6 €/kgH2 in order to make the CO2 to methanol plant competitive with a MeOH market price of 550 €/tonMeOH; synthesis reactor operating conditions have more limited impact from a cost perspective, except for the purge fraction that shall be optimized to maximize the amount of MeOH produced.
Design and experimental set-up of hydrogen based microgrid: characterization of components and control system development
Authors: Cava Carmine , Cosentini Carlotta , Gagliardi Gabriele Guglielmo , Cedola Luca , Caputi Michele Vincenzo Migliarese , Aresti Marco , Borello Domenico 
Published: December 2022

Abstract
In this study, the implementation of a hydrogen microgrid is investigated, considering the integration of H
2 production, storage, and energy conversion to feed a typical end-user. A remote control system has been realized through LabVIEW software, allowing to monitor real-time all the devices and analyze their performances. The integrated system is composed of a PEM electrolyzer (325 W), a storage system based on metal hydrides (two tanks, 54 g of hydrogen each, 1.08 wt%) and an energy converter (PEM Fuel Cell stack, 200 W). A programmable electronic load was used to set a power demand throughout the year, simulating an end-user. Data collected from each component of the micro-grid were used to characterize the energetic performance of the devices, focusing on the H
2 production via electrolyzer, charging cycles of the H
2 storage system, and energy conversion efficiency of the FC stack. Finally, the global efficiency of the microgrid is computed. Even though the system is realized in laboratory scale, this circumstance will not invalidate the significance of the configuration due to modularity of all the technologies that can be easily scaled up to realistic scales.
Thermodynamic Analysis of a Small-scale Biomethane Liquefaction Process
Authors: Tamburrano P , Salvatori M , Fedele M , Meschia M , Distaso E , De Palma P , Amirante R 
Published: December 2022

Abstract
Liquid biomethane, obtained from anaerobic digestion of organic biomass, upgrading and liquefaction processes, is regarded as one of the most effective renewable biofuels to be extensively employed in the transport and power generation sectors for mitigation of greenhouse gas emissions. In this paper, a novel biomethane liquefaction process for small-scale plants is presented and thermodynamically assessed by means of a detailed thermodynamic model that employs the libraries of Fluid Prop, being very accurate for thermodynamic calculations of complex fluids. The thermodynamic model allows the heat exchanger geometry to be accurately determined and crucial parameters to be adjusted, such us the composition of the refrigerant and the operating conditions of both the biomethane and the refrigerant. The proposed model has general validity and can also be used to study the most promising biomethane liquefaction technologies for small-scale plants.
Advances in 1D thermo-fluid dynamic simulation of SI hydrogen-fueled engine
Authors: Ballerini Alberto , Cerri Tarcisio , Marinoni Andrea Massimo , Onorati Angelo 
Published: December 2022

Abstract
This work has the objective to describe the improvement introduced in the 1D thermo-fluid dynamic simulation code developed to simulate hydrogen-fueled Internal Combustion Engines. Two main topics have been analyzed. The first regarding the simulation of unsteady flows in the whole intake and exhaust system and the injection process of the fuel, considering a mixture of ideal gases as working fluid with specific heats depending on both gas temperature and composition. The second one focused on the combustion process, where the correlation-based approach used to compute the laminar flame speed for the homogeneous air-hydrogen mixture has been substituted by a Tabulated Kinetic approach. New correction factors that account for surface instabilities have been also added to obtain a more accurate prediction of the combustion process. The modifications introduced have been validated against experimental values comparing in-cylinder pressure trends, intake and exhaust instantaneous pressure pulses taken at different locations. Finally, the results obtained from the simulations of a novel hydrogen-fueled heavy-duty engine are presented.
A dynamic model of a Hybrid Electric Propulsive System for degradation assessment
Authors: Donateo T , Spada Chiodo L , Ficarella A 
Published: December 2022

Abstract
The present study proposes a model for the simulation of the steady-state and transient behaviors of a Hybrid Electric Propulsive System (HEPS), in presence of several forms and degrees of performance degradation. The power system, which is made of a turboshaft engine coupled with an electric power source is intended for urban air mobility applications. The proposed model encompasses the capability of modeling battery aging effects, and, consequently, updating the performance of the system with battery life. Moreover, the versatility of the proposed model makes it suitable for the analysis of the dynamic behavior of the system, for example in presence of small perturbations around predefined operational settings or following a known mission profile. In this investigation the model is applied to the test of the HEPS under different operating conditions with different degradation criteria, affecting both the thermal and the electric drive with different levels of severity. The application of the model allowed the generation of relevant information concerning the propulsive system state of health which will be processed with the employment of machine learning algorithms in an accompanying paper.
A methodology to initialize tumble flow fields for fast 3D-CFD simulations of pent-roof SI engines
Authors: Ramognino F , Sforza L , Lucchini T , D’Errico G , Onorati A 
Published: December 2022

Abstract
The demand of powertrain technologies able to efficiently employ several non-fossil fuels types, as bio or synthetic ones, compels to develop simplified strategies to accelerate the engines industrial optimization. High-tumble ultra-lean SI engines are currently an attractive option, thanks to their fuel flexibility and the potential of extending the lean combustion limit with novel ignition strategies. This work presents a methodology to initialize tumble flow fields at closed-valves inside pent-roof SI engines, without the need of simulating the gas exchange process. First, assuming an elliptical-shaped vortex, a velocity field is initialized into the cylinder according to the target tumble ratio at inlet valve closing (IVC). Then, the flow field is evolved at fixed piston position for a time duration proportional to the integral time scale of turbulence. This process is essential to adapt the vortex morphology to the surrounding geometrical details, despite some kinetic energy is lost due to frictions. To compensate this last effect, the velocity field is re-scaled at the end of the process to match the initial tumble ratio. Finally, the parameters affecting the tumble initialization are calibrated by comparing the development of the flow-field during the compression stroke with the results from a full-cycle simulation in a pent-roof SI engine. The methodology is validated on the Darmstadt optical engine. First, the numerical velocity fields are compared against PIV measurements at different crank-angles. Then, the combustion prediction is also evaluated, to assess the quality of the initialized tumble flow field. The achieved results are satisfactory, demonstrating the industrial applicability of the presented methodology.
Numerical Investigation on the Effects of the Setting of the Load Control System of a Formula SAE Single-Cylinder Turbocharged Engine on Fuel Efficiency and Performance
Authors: Raspanti S , Ciampolini M , Bigalli S , Fabiani A , Romani L , Ferrara G 
Published: December 2022

Abstract
The target of motorsport has always been maximising the performance. Increasingly stringent rules on fuel usage, however, have moved the research on engine design and control rules toward efficiency enhancement. Turbocharging is a typical solution to match both targets; however, it suffers from the turbo-lag phenomenon, especially when the maximum power is limited by an air restrictor. In the present paper, an investigation on a combined solution aimed at contemporarily improving transient response and efficiency in FSAE events, both leading to a higher score, is carried out. In detail, the adoption of an anti-lag valve and an efficiency-based control schedule, markedly exploiting the wastegate actuator, is proposed in place of the classic combination blow-off valve and performance-based strategy. The analyses were carried out on the 520 cm3 single-cylinder 4-stroke turbocharged engine of the Firenze Race Team. In order to predict the potential of the proposed load control solution, a predictive combustion engine model (which design process is exhaustively described in the paper), adopting the K-k-ε turbulence model, was developed in the GT-Suite software and calibrated by means of test-bench data and 3-D CFD analyses. A vehicle model, calibrated by means of telemetry data, was finally developed to compare the proposed solution to the baseline load control system in typical race conditions, showing benefits in terms of performance, drivability, and efficiency.
1D/3D simulation procedure to investigate the potential of a lean burn hydrogen fuelled engine
Authors: Teodosio Luigi , Berni Fabio , Lanotte Alfredo , Malfi Enrica 
Published: December 2022

Abstract
In recent years hydrogen, especially the one generated by renewable energy, is gaining increasing attention as a clean fuel to support the future mobility towards efficient and low emission solutions for propulsion systems. In this scenario, the present work deals with the virtual conversion of a single-cylinder Diesel engine, conceived for marine applications, into a hydrogen Spark Ignition (SI) unit. A simulation methodology is adopted, combining 1D and 3D Computational Fluid Dynamics (CFD) methods. First, experiments are realized on the original Diesel engine mounted on a test bench, collecting main performance indicators and emissions. A complete 1D engine model (GT-Power™) is developed and validated against measurements. Then, a 3D model of the cylinder (STAR-CD) is set-up and the related combustion outcomes are compared both with 1D and experimental results, showing an overall good agreement. In the second stage, the Diesel unit is converted into a port-injected hydrogen SI engine; the 3D model is re-arranged and utilized to reproduce pre-mixed hydrogen combustions under ultra-lean air/fuel (A/F) mixtures. Also, the 1D model is partly modified and coupled to an advanced combustion sub-model integrated with fast tabulated chemical kinetics to predict the knock. In particular, 1D combustion evolution is calibrated against the results of 3D CFD hydrogen combustion simulation. Finally, the calibrated 1D model is applied to investigate the advantages of ultra-lean hydrogen combustion in terms of efficiency, NO, and unburned H2 formation at medium/high loads.
New Experimental Vapor-Liquid Equilibria Data and Thermodynamic Modelling for R1234yf/propane/R32 as low-GWP Mixtures in Heat Pump Applications
Authors: Panzeri A , Bona D Di , Signorini S , Molinaroli L , Gatti M 
Published: December 2022

Abstract
This paper presents new experimental results for the Vapor – Liquid Equilibria of binary mixtures of R1234yf and propane at 277 and 313 K. The newly collected data are then used, in combination with other existing data retrieved from the literature, to calibrate the Peng-Robinson Equation of State with suitable accuracy for domestic vapour compression heat pump cycles simulations. After calibration, the Equation of State is applied to numerical simulations, in Aspen Plus, aimed at finding the optimal refrigerant composition, among ternary mixtures containing R1234yf, propane and R32. Results identify a Pareto curve where the optimal mixtures (with flammability lower or equal to A2L and GWP < 500) are represented in terms of two contrasting objectives: COP and the volumetric heating effect. Ternary mixtures containing propane and R1234yf respectively in the range 0÷12%mass and 18÷30%mass are Pareto optimal: the mixture with the best COP (2.7% lower than R410A one) is the binary pair R32 = 70% + R1234yf = 30%, a composition very close to the one of the commercial refrigerant R454B. On the other hand, the mixture with the largest volumetric effect (6.5% higher than R410A one) is the ternary blend R32 = 70% + R1234yf = 18% + propane = 12%. This study confirms that is quite challenging to find R410A replacements featuring at the same time reasonable heating capacity and a COP not lower than R410A one.
Butane-based heat pump for advanced GTCC applications: static and dynamic model validation
Authors: Anfosso Chiara , Gini Lorenzo , Mantelli Luca , Ferrando Marco , Reboli Tommaso , Traverso Alberto 
Published: December 2022

Abstract
The Thermochemical Power Group (TPG) of the University of Genoa is investigating innovative solutions to increase the flexibility of gas turbine combined cycles (GTCC) and extend their operative range by integrating large size high performance heat pumps. Achieving this goal would make GTCCs more competitive in the future energy market, which will be characterized by a heavy presence of non-dispatchable renewable energy sources.
Within this framework, the authors designed and built a new experimental facility to emulate advanced GTCCs at laboratory scale, integrating a 100 kWel micro gas turbine (MGT), a 10 kWel heat pump (HP) and a 180 kWh cold thermal energy storage (TES), with scale-up equations and dynamic models, capable of hardware-in-the-loop tests.
The focus of this article is on the HP, which uses n-butane (R600) as working fluid and can be used both to heat and cool down the MGT compressor intake. The HP features one superheater and a 6-cylinder reciprocating compressor, which rotational speed can be continuously varied from 900rpm to 1800rpm.
A dynamic model of the HP was developed in TRANSEO, with dedicated Matlab-Simulink® models. This model includes all the components of the HP closed loop, making it possible to simulate its performance and monitor all the main process parameters, such as compressor operation and condensing pressure. This model can be used to simulate the HP in various conditions, including part-load and transient operations, and to aid the design of the advanced GTCC control system. The evaporator and condenser models solve a system of non-linear equations to compute pressure, temperature, and distribution of the different phases of the working fluid along the heat exchangers. Such phase distribution is computed following a moving boundary approach.
An experimental campaign was carried out to collect data regarding the stationary performance of the HP. Values of COP and thermal power were analysed as a function of compressor speed and pressure at the condenser, keeping the conditions at the evaporator constant. Then, its transient behaviour was characterized, observing its response to step changes of both evaporator and condenser thermal loads. The model was then successfully calibrated and validated on both stationary and transient data, showing good accuracy.
Based on these results, it will be possible to integrate the HP model within larger system simulation tools. Having an accurate digital twin of the whole GTCC integrating HPs and TES will make possible to develop and verify complex control logics on many different scenarios, relying on a safe model-in-the-loop setup, before actual implementation in the field.
Using Life Cycle Assessment in tenders to enhance the sustainable procurement of External Thermal Insulation Composite Systems
Authors: Cardarelli A , Baffo I , Ubertini S , Barbanera M 
Published: December 2022

Abstract
Green Public Procurement (GPP) is a policy instrument to decrease the environmental impact of products and services and create environmental value for society. A new method for assessing environmental award criteria in GPP processes was developed to integrate environmental and economic criteria into public tenders for External Thermal Insulation Composite Systems (ETICS). The main objective of this study was to identify the effect that the inclusion of environmental impacts can have on decision-making in public procurement. At this scope, an environmental benchmark for the main phases of the supply chain (production, installation and disposal) of ETICS that use different insulating materials, including EPS and mineral wool, was defined for different Life Cycle Assessment (LCA) impact categories after a detailed literature review. Then the monetisation method of the externalities was applied to combine the environmental impacts and the direct costs associated with the manufacture of the ETICS system by obtaining a single score for the selection of the best bid from the environmental and economic point of view. This methodology was implemented in a spreadsheet and a case study was analysed as a practical application of the tool developed for the determination of the global index. The case study simulated a tender in which three contractors provided their bid for an ETICS system. The overall investigation of the results obtained in the case study showed that the environmental externalities have a rather limited incidence compared to direct costs (between 0.8 and 10%). However, even if the lower direct costs were provided by contractor 1 (87.72 €/m2) in comparison to contractor 2 (87.80 €/m2) and contractor 3 (92.74 €/m2), the slightly higher environmental impacts caused the costs to rise. The most environmentally and economically advantageous bid was then provided by contractor 2, for which the global index was the lowest for each monetisation method applied. For all the impact categories considered, the production stage (A1-A3) represents the most significant contribution. The thermal insulation material and the finishing coat provide the greatest contribution to the environmental impact. The tool was designed to improve the knowledge of the economic and environmental performances of ETICS systems, which might be also used by public administrations to define minimum environmental requirements and maximum specific costs when preparing tenders for the energy requalification of buildings.
Thermodynamic Analysis of a Parabolic Trough Collector (PTC) operating with gas-phase nanofluids
Authors: Settino Jessica , Ferraro Vittorio , Carpino Cristina , Marinelli Valerio 
Published: December 2022

Abstract
Parabolic Trough Collectors (PTC) are the most developed and established technology among the concentrated solar power systems. However, the majority of the PTC power plants currently in operation uses synthetic oils or molten salts as heat transfer fluids (HTF), with a limited operating temperature range. To operate at higher temperatures, the use of pressurized gases as working fluid has been recently proposed in several studies. However, in this case a large pumping power is required. In this work, the use of gas-solid suspensions in a commercial PTC has been analyzed. A thermodynamic analysis has been performed to investigate the effect of three different gas-solid suspensions: Argon-Al2O3, Carbon Dioxide-Al2O3 and Air-Al2O3. The performance of these gas-phase nanofluids has been compared to the use of pure gases. Power output, pumping power, outlet fluid temperature and global efficiency of the parabolic trough system have been determined. The analysis shows a substantial decrease of the pumping power. Thanks to this advantage, the use of gas-phase nanofluids in parabolic trough collectors could represent an interesting possibility.
How to Increase Savonius Power Coefficient: Ducted Rotor Performance with Different Overlap Ratios
Authors: Brusca S , Galvagno A , Lanzafame R , Mauro S , Messina M 
Published: December 2022

Abstract
The use of ducted configuration to increase the efficiency of wind turbine rotors is gaining wide attention in the scientific community. Specifically for mini and micro rotors in urban environment applications this solution demonstrated to be very attractive. The possibility to overcome the Betz limit for power coefficient was widely demonstrated in ducted horizontal axis wind turbines. However, very few studies have dealt with ducted Savonius rotor despite these rotors represented an efficient solution for urban environment thanks to their simplicity, their cheapness and the low cut in velocity in highly turbulent conditions as well. Furthermore, the ducted Savonius concept, might be applicable to oscillating water column wave energy devices, thanks to its self-rectifying capability and simplicity. For these reasons, the authors carried out an experimental campaign to verify the impact of ducting the Savonius rotor, thus leading the way for a possible exploitation of this configuration in many practical applications. Specifically, The present paper deals with a study of ducted Savonius type air turbine performance. In particular, turbine performance was studied as a function of turbine overlap ratio. Four overlap ratios were tested: 0, 1/6, 1/3 and 1/2. A specific experimental setup was built to test ducted turbine, while bare turbine performance was measured using a wind tunnel. All tests were performed at fixed air velocity: 5 m/s. On the basis of the results, it is possible to state that ducted turbine performance is higher than bare turbine performance, at all tip speed ratios and for all overlap ratios. The optimal turbine overlap ratio is equal of 1/3.