• Energy Research

Abstract To contrast the naval emissions in terms of Sulphur and Nitroxides, recently, the institution of Emission Control Areas has increasingly prompted shipowners to choose new-generation engines capable of using Liquified Natural Gas as a marine fuel. This study presents a comparative Life Cycle Assessment, cradle-to-grave, between two different engines on a cruise ferry. One is a traditional Diesel machinery system and the other is a Liquified Natural Gas one. The two configurations have been analysed within 17 different impact categories in terms of climate change, human health, resourced depletion and ecosystems. The studied phases of the ship's life were the building, operation and dismantling. The results showed and quantified the environmental differences deriving from the use of Liquified Natural Gas in all the phases of the life of the ship. Generally, the LNG propulsion has shown to be more environmentally performing, but, particularly interesting are the results in terms of climate change, influenced by lower CO2 emissions but also by the phenomenon of methane slip that can increase the CO2-equivalent effect. The energy costs of transport and liquefaction of gas also have an impact to consider. Analyses of uncertainty on the data and of sensitivity on fuel consumptions and losing of steel during the shipbuilding were carried out.

Our cultural society has made remarkable advancements in creating digital models that depict the built environment, landscape, and reality. The advent of technologies such as terrestrial laser scanning and drone-based photogrammetry, coupled with sophisticated software capable of processing hundreds of photographs to generate point clouds, has elevated the significance of three-dimensional surveying in documentation and restoration. Point cloud processing and modeling software enable the creation of precise digital replicas of the investigated architecture, which can be scaled down and transformed into physically identical models. Through the export of STL files and the utilization of both subtractive and additive 3D printing technologies, tactile models resembling traditional manually crafted plastics can be obtained. An exemplary study focuses on the Gothic church of Santa Maria Alemanna in Messina, Italy, where laser scanner surveys and 3D prints using various technologies were applied to different parts of the building. The models were produced using a CNC milling machine and a 3D printer for fused deposition modeling. The sustainability of these production technologies was assessed through a Life Cycle Assessment, demonstrating the environmental advantages of additive manufacturing, including the use of materials with high recyclability and lower energy consumption. Additionally, the additive approach helps reduce processing waste.

In the production of utility poles, used for transmission, telephony, telecommunications or lighting support, for many years, the steel has almost entirely replaced wood. In recent years, however, new composite materials are a great alternative to steel. The questions are: is the production of composite better in terms of environmental impact? Is the lifecycle of composite pole more eco-sustainable than lifecycle of steel pole? Where is the peak of pollution inside the lifecycle of both of technologies? In the last years, in order to deal with new European polices in environmental field, a new approach for the impact assessment has been developed: the Life Cycle Assessment. It involves a cradle-to-grave consideration of all stages of a product system. Stages include the extraction of raw material, the provision of energy for transportation and process, material processing and fabrication, product manufacture and distribution, use, recycling and disposal of the wastes and the product itself. A great potentiality of the Life Cycle assessment approach is to compare two different technologies designed for the same purpose, with the same functional unit, for understanding which of these two is better in terms of environmental impact. In this study, the goal is to evaluate the difference in environmental terms between two different technologies used for the production of poles for illumination support.

Domestic appliance are widely used in all countries. During the design phase, it is very important to take advantage of new virtual prototyping technologies in order to improve the user expectations and put the feeling of the user with the device in the centre of the design. The paper deals with the complete simulation of the opening of the front door of an appliance like a refrigerator or an oven. The process is simulated with the use of ad-hoc built program that uses a combination of experimental parameters and virtual fluid dynamic simulations. Each moment involved during the opening of the door is evaluated and a comprehensive explanation of each of them is reported. The entire solving process is parametrized in order to use it in an iteration loop for eventually optimization of the User Experience and the comfort during the opening of the front door. A fridge case study is described and discussed.

Savonius turbines are widely used in energy recovery applications, including urban-integrated wind energy systems and Oscillating Water Column (OWC) setups for wave energy conversion. This study explores the use of a ducted Savonius turbine. Experimental tests were conducted on a scaled turbine to evaluate its performance. A Computational Fluid Dynamics (CFDs) model, incorporating Sliding Mesh and Dynamic Fluid Body Interaction (DFBI) techniques, was developed to replicate the experimental conditions. The accuracy of the model was confirmed through validation against experimental data. In total, four conditions were studied: one without a Power Augmenter, one with the Bell-Metha Power Augmenter, and two custom ones obtained by increasing the slope at the end of the Power Augmenters. To facilitate rapid turbine characterization, a fast computational method was developed, allowing the derivation of characteristic curves using only three CFD simulations per configuration. The reliability of this approach was assessed by comparing predictions with experimental results. Developing such a model is crucial, as it enables seamless integration with Reduced-Order Models (ROMs), significantly improving efficiency in evaluating multiple operating points. Compared to traditional experimental testing, this approach provides a faster and more efficient way to obtain performance insights, paving the way for enhanced turbine optimization and real-world deployment.

An Oscillating Water Column device, specifically a Savonius turbine, underwent comprehensive testing within an air duct to evaluate its performance under varying rotational speeds, flow directions, and the presence of power augmenters positioned both in front of and behind the device. The experimental setup involved the utilization of load cells and pressure transducers, with their data utilized to calculate pressure differentials across the turbine and torque. Subsequently, a predictive model based on decision trees was developed using Machine Learning. This model was then used to analyze the influence of various features on predicting the pressure difference, considered as the output. The results of the validation (10-fold cross-validation) and test phases were thoroughly investigated. Moreover, obtaining a predictive model allows for the exploration of different scenarios without relying solely on physical experimentation, thereby broadening the scope for further testing.

This review explores a variety of techniques that utilize air injections beneath a vessel’s hull to reduce drag and consequently improve energy efficiency. It focuses on the methodologies of microbubble drag reduction (MBDR), air layer drag reduction (ALDR), and air cavity drag reduction (ACDR), offering insights into their design, operational mechanisms, and potential applications. This review provides a detailed examination of the underlying principles of these technologies, incorporating a blend of experimental research, numerical simulations, and mathematical modelling to offer a comprehensive understanding. It references recent experimental data, highlighting how these findings corroborate with numerical simulations and are further explained through mathematical models. Conclusively, this review accentuates the transformative influence of air injection methods in drag reduction within the maritime industry, emphasizing their pivotal role in boosting operational efficiency, reducing environmental impact, and driving the evolution of naval design and transportation. Through a balanced and detailed analysis, this review provides a holistic view of the current state and future prospects of these innovative resistance reduction strategies.