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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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13 pages, 11638 KiB  
Article
A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants
by Daniele Fiaschi, Giampaolo Manfrida, Barbara Mendecka, Lorenzo Tosti and Maria Laura Parisi
Sustainability 2021, 13(8), 4527; https://doi.org/10.3390/su13084527 - 19 Apr 2021
Cited by 11 | Viewed by 2843
Abstract
In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are [...] Read more.
In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies. Full article
(This article belongs to the Special Issue Sustainable Geothermal Energy)
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25 pages, 351 KiB  
Article
Public Norms in Practices of Transitional Planning—The Case of Energy Transition in The Netherlands
by Willem Salet
Sustainability 2021, 13(8), 4454; https://doi.org/10.3390/su13084454 - 16 Apr 2021
Cited by 10 | Viewed by 3555
Abstract
The fallibility of intervening in complex realities is widely recognized in planning theory. The prevailing planning approaches of the last two decades may be summarized as attempts to make planning more responsive, corrective, and resilient, and also more sociocratic vis à vis the [...] Read more.
The fallibility of intervening in complex realities is widely recognized in planning theory. The prevailing planning approaches of the last two decades may be summarized as attempts to make planning more responsive, corrective, and resilient, and also more sociocratic vis à vis the traditional government-centric rationalization of planning. These adaptations make sense, yet keep planning within the pragmatic scope of purposive aspirations and pragmatic problem solving. The pivotal statement of the article is that purposive systems run down in complex societies when not adequately sustained by institutionalizing sets of public norms. Public norms fulfil a different function than goal orientation. They provide a normative compass in times of uncertainty and set conditions to social interaction rather than organizing the performance of objectives or solving problems. The article aims to highlight the interrelationships of public norms and pragmatic strategies of planning. Empirically, the article addresses the major turning points of Dutch climate policy concerning the transitions of the electricity market, the major municipal–entrepreneurial initiatives of city-heating, and the decentralization of climate policies. The method of analysis is based on policy analysis of legislation, policy documents, and published contributions to public debates. The results of the analysis highlight the differences between the high policy aspirations and the outcomes. The results give evidence of the wicked problems in the complex energy transition. The discussion questions the mischievousness of ‘good’ planning intentions in complex social figurations, and critically examines the institutionalization of the material norms and the norms of politico-ordinance. The conclusions suggest that the social normalization of public norms in Dutch climate policies is not yet adequately materialized to effectively cope with wicked problems. Full article
(This article belongs to the Special Issue Cultural, Legal and Political Dimensions of Public Norms in Sustainable Metropolitan Spaces)
16 pages, 5248 KiB  
Article
Flood Hazard Assessment Mapping in Burned and Urban Areas
by Hariklia D. Skilodimou, George D. Bathrellos and Dimitrios E. Alexakis
Sustainability 2021, 13(8), 4455; https://doi.org/10.3390/su13084455 - 16 Apr 2021
Cited by 54 | Viewed by 5720
Abstract
This study proposes a simple method to produce a flood hazard assessment map in burned and urban areas, where primary data are scarce. The study area is a municipal unit of Nea Makri, a coastal part of the eastern Attica peninsula (central Greece), [...] Read more.
This study proposes a simple method to produce a flood hazard assessment map in burned and urban areas, where primary data are scarce. The study area is a municipal unit of Nea Makri, a coastal part of the eastern Attica peninsula (central Greece), which has been strongly urbanized and suffered damage from urban fires in 2018. Six factors were considered as the parameters most controlling runoff when it overdraws the drainage system’s capacity. The analytical hierarchy process (AHP) method and a geographical information system (GIS) were utilized to create the flood hazard assessment map. The outcome revealed that the areas with highest flood hazard are distributed in the eastern and southern parts of the study area, as a result of the combination of lowlands with gentle slopes, torrential behavior of the streams, streams covered by construction, increasing urbanization and burned areas. The uncertainty and the verification analyses demonstrate a robust behavior for the model predictions, as well as reliability and accuracy of the map. Comparing the existing urban fabric and road network to the potential flood hazard areas showed that 80% of the urban areas and 50% of the road network were situated within areas prone to flood. The method may be applied to land use planning projects, flood hazard mitigation and post-fire management. Full article
(This article belongs to the Special Issue Natural and Technological Hazards in Urban Areas: Assessment, Planning and Solutions)
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17 pages, 1694 KiB  
Article
Adaptive Volt-Var Control Algorithm to Grid Strength and PV Inverter Characteristics
by Toni Cantero Gubert, Alba Colet, Lluc Canals Casals, Cristina Corchero, José Luís Domínguez-García, Amelia Alvarez de Sotomayor, William Martin, Yves Stauffer and Pierre-Jean Alet
Sustainability 2021, 13(8), 4459; https://doi.org/10.3390/su13084459 - 16 Apr 2021
Cited by 9 | Viewed by 3607
Abstract
The high-penetration of Distributed Energy Resources (DER) in low voltage distribution grids, mainly photovoltaics (PV), might lead to overvoltage in the point of common coupling, thus, limiting the entrance of renewable sources to fulfill the requirements from the network operator. Volt-var is a [...] Read more.
The high-penetration of Distributed Energy Resources (DER) in low voltage distribution grids, mainly photovoltaics (PV), might lead to overvoltage in the point of common coupling, thus, limiting the entrance of renewable sources to fulfill the requirements from the network operator. Volt-var is a common control function for DER power converters that is used to enhance the stability and reliability of the voltage in the distribution system. In this study, a centralized algorithm provides local volt-var control parameters to each PV inverter, which are based on the electrical grid characteristics. Because accurate information of grid characteristics is typically not available, the parametrization of the electrical grid is done using a local power meter data and a voltage sensitivity matrix. The algorithm has different optimization modes that take into account the minimization of voltage deviation and line current. To validate the effectiveness of the algorithm and its deployment in a real infrastructure, the solution has been tested in an experimental setup with PV emulators under laboratory conditions. The volt-var control algorithm successfully adapted its parameters based on grid topology and PV inverter characteristics, achieving a voltage reduction of up to 25% of the allowed voltage deviation. Full article
(This article belongs to the Special Issue Integration and Control of Renewable Energy and Power Electronics for Future Power Systems)
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21 pages, 6623 KiB  
Article
An Approach to the Operation Modes and Strategies for Integrated Hybrid Parabolic Trough and Photovoltaic Solar Systems
by José A. López-Álvarez, Miguel Larrañeta, Elena Pérez-Aparicio, Manuel A. Silva-Pérez and Isidoro Lillo-Bravo
Sustainability 2021, 13(8), 4402; https://doi.org/10.3390/su13084402 - 15 Apr 2021
Cited by 5 | Viewed by 2559
Abstract
Concentrated solar power (CSP) and photovoltaic (PV) solar systems can be hybridized, creating synergies: on one hand procuring dispatchability by storing thermal energy, and on the other hand generating electricity at a highly competitive prize. In this paper, we present an approach to [...] Read more.
Concentrated solar power (CSP) and photovoltaic (PV) solar systems can be hybridized, creating synergies: on one hand procuring dispatchability by storing thermal energy, and on the other hand generating electricity at a highly competitive prize. In this paper, we present an approach to the operation strategies and modes for integrated hybrid CSP + PV systems. We focus on parabolic trough (PT) solar plants, especially those operating in the south of Spain. Our study consists in the definition of suitable states for each of the subsystems that constitute a hybrid solar plant. We then propose modes from the combination of suitable states and establish the conditions for the transition between modes depending on the operation strategy. We propose two operation strategies: demand coverage and base load production. The results of this paper can be used in decision making for hybrid solar system simulation programs. Full article
(This article belongs to the Special Issue Solar Power System and Sustainability)
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25 pages, 1519 KiB  
Article
Improving Energy Efficiency in Buildings Using an Interactive Mathematical Programming Approach
by Christina Diakaki and Evangelos Grigoroudis
Sustainability 2021, 13(8), 4436; https://doi.org/10.3390/su13084436 - 15 Apr 2021
Cited by 4 | Viewed by 2083
Abstract
Improving energy efficiency in buildings is a major priority and challenge worldwide. The employed measures vary in nature, and the decision analyst, who is typically the architect, the engineer, or the building expert that has undertaken the task to suggest energy efficient solutions, [...] Read more.
Improving energy efficiency in buildings is a major priority and challenge worldwide. The employed measures vary in nature, and the decision analyst, who is typically the architect, the engineer, or the building expert that has undertaken the task to suggest energy efficient solutions, faces a complex decision problem comprising numerous decision variables and multiple, usually competitive objectives. The solution of such multi-objective problems typically involves some sort of objectives aggregation, which reflects the preferences of the involved final decision maker that is the building’s user, occupant, and/or owner. The preferences elicitation, however, is a difficult task, and this paper aims to provide an interactive framework that will allow their consideration in a relatively easy manner. More specifically, a mathematical programming approach is proposed herein, which allows the elicitation and incorporation of the decision maker’s preferences in the decision model via the assessment of his/her utility function with the assistance of the multicriteria decision aid method UTASTAR. To study the feasibility and efficiency of the proposed approach, the case of a simple building is examined as an application example. The study results suggest that the proposed approach is capable of helping the decision analyst to suggest energy measures that satisfy, as much as possible, the decision maker’s preferences, without having to precisely prescribe them beforehand. Full article
(This article belongs to the Special Issue Energy Transition and Climate Change in Decision-making Processes)
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22 pages, 2527 KiB  
Article
Aerodynamic Characteristics of Airfoil and Vertical Axis Wind Turbine Employed with Gurney Flaps
by Yosra Chakroun and Galih Bangga
Sustainability 2021, 13(8), 4284; https://doi.org/10.3390/su13084284 - 12 Apr 2021
Cited by 19 | Viewed by 4427
Abstract
In the present studies, the effects of Gurney flaps on aerodynamic characteristics of a static airfoil and a rotating vertical axis wind turbine are investigated by means of numerical approaches. First, mesh and time step studies are conducted and the results are validated [...] Read more.
In the present studies, the effects of Gurney flaps on aerodynamic characteristics of a static airfoil and a rotating vertical axis wind turbine are investigated by means of numerical approaches. First, mesh and time step studies are conducted and the results are validated with experimental data in good agreement. The numerical solutions demonstrate that the usage of Gurney flap increases the airfoil lift coefficient CL with a slight increase in drag coefficient CD. Furthermore, mounting a Gurney flap at the trailing edge of the blade increases the power production of the turbine considerably. Increasing the Gurney flap height further increases the power production. The best performance found is obtained for the maximum height used in this study at 6% relative to the chord. This is in contrast to the static airfoil case, which shows no further improvement for a flap height greater than 0.5%c. Increasing the angle of the flap decreases the power production of the turbine slightly but the load fluctuations could be reduced for the small value of the flap height. The present paper demonstrates that the Gurney flap height for high solidity turbines is allowed to be larger than the classical limit of around 2% for lower solidity turbines. Full article
(This article belongs to the Special Issue Consistent Computational Approaches for Wind Energy Applications)
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16 pages, 2449 KiB  
Article
Energy Transition toward Cleaner Energy Resources in Nepal
by Tika Ram Pokharel and Hom Bahadur Rijal
Sustainability 2021, 13(8), 4243; https://doi.org/10.3390/su13084243 - 11 Apr 2021
Cited by 16 | Viewed by 9454
Abstract
Energy is an important input for socioeconomic development and human well-being. The rationality of energy transitions toward cleaner energy resources is not only to improve individual living conditions, but also to enhance the economic growth of a nation. Nepal is considered to be [...] Read more.
Energy is an important input for socioeconomic development and human well-being. The rationality of energy transitions toward cleaner energy resources is not only to improve individual living conditions, but also to enhance the economic growth of a nation. Nepal is considered to be one of the countries with a low per-capita electricity use, heavily relying on traditional energy resources such as firewood and agricultural residues. The country is rich in hydropower resources. However, various economic and socioeconomic constraints have left the significant potential for hydroelectricity untapped. This study describes the energy transition patterns in Nepal based on a literature review and field survey of household energy use in the winter. We collected data from 516 households in the Solukhumbu, Panchthar, and Jhapa districts of Nepal. The rate of per-capita electricity consumption was 330 kWh/capita/year, which is significantly lower than that of other contemporary global societies such as India 1000 and China 4900 kWh/capita/year. The increasing trend in hydroelectricity production has optimistically transformed the energy sector toward cleaner resources; this correlates with the GDP per capita. Solar home systems, mini- and micro-hydropower plants, biogas technology, and improved cook stoves have been widely used, which has lowered the health and environmental burdens in rural areas. By analysing the survey data, we found that 25% of the households only relied on traditional cooking fuel, while 67% and 8% of the households relied on mixed and commercial cooking fuels, respectively. Moreover, 77% and 48% of traditional and mixed-fuel-using households were unhappy with current cooking fuels while 40% and 66% of these households preferred to use clean cooking fuels. The share of traditional energy resources decreased from 78% to 68%, while that of commercial energy resources increased from 20% to 28% from 2014/15 to 2019/20. This study suggests that future energy policies and programs should acknowledge the reality of energy transition to achieve sustainability by establishing reliable and clean sources of energy. Full article
(This article belongs to the Special Issue Sustainable Integration of Renewable Power Generation Systems)
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38 pages, 651 KiB  
Article
Economizing the Uneconomic: Markets for Reliable, Sustainable, and Price Efficient Electricity
by Mohammad Rasouli and Demosthenis Teneketzis
Sustainability 2021, 13(8), 4197; https://doi.org/10.3390/su13084197 - 9 Apr 2021
Viewed by 2450
Abstract
Current electricity markets do not efficiently achieve policy targets i.e., sustainability, reliability, and price efficiency. Thus, there are debates on how to achieve these targets by using either market mechanisms e.g., carbon and capacity markets, or non-market mechanisms such as offer-caps, price-caps, and [...] Read more.
Current electricity markets do not efficiently achieve policy targets i.e., sustainability, reliability, and price efficiency. Thus, there are debates on how to achieve these targets by using either market mechanisms e.g., carbon and capacity markets, or non-market mechanisms such as offer-caps, price-caps, and market-monitoring. At the same time, major industry changes including demand response management technologies and large scale batteries bring more elasticity to demand; such changes will impact the methodology needed to achieve the above mentioned targets. This work provides market solutions that capture all three policy targets simultaneously and take into account the above-mentioned industry changes. The proposed solutions are based on: (i) a model of electricity markets that captures all the above mentioned electricity policy targets; (ii) mechanism design and the development of a framework for design of efficient auctions with constraints (individual, joint homogeneous, and joint non-homogeneous). The results show that, within the context of the proposed model, all policy targets can be achieved efficiently by separate capacity and carbon markets in addition to efficient spot markets. The results also highlight that all three policy targets can be achieved without any offer-cap, price-cap, or market monitoring. Thus, within the context of the proposed model, they provide clear answers to the above-mentioned policy debates. Full article
(This article belongs to the Special Issue Renewable Energy Technologies for Sustainable Development)
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24 pages, 47457 KiB  
Article
Human Dimensions of Urban Blue and Green Infrastructure during a Pandemic. Case Study of Moscow (Russia) and Perth (Australia)
by Diana Dushkova, Maria Ignatieva, Michael Hughes, Anastasia Konstantinova, Viacheslav Vasenev and Elvira Dovletyarova
Sustainability 2021, 13(8), 4148; https://doi.org/10.3390/su13084148 - 8 Apr 2021
Cited by 57 | Viewed by 9099
Abstract
Significant challenges of the COVID-19 pandemic highlighted that features of a modern, sustainable and resilient city should not only relate to fulfilling economic and social urban strategies, but also to functional urban design, in particular, related to urban blue and green infrastructure (BGI). [...] Read more.
Significant challenges of the COVID-19 pandemic highlighted that features of a modern, sustainable and resilient city should not only relate to fulfilling economic and social urban strategies, but also to functional urban design, in particular, related to urban blue and green infrastructure (BGI). Using results from a web-based questionnaire survey conducted May–July 2020 in Moscow (Russia) and Perth (Australia), this paper provides insights regarding citizens’ needs for and values of urban BGI as well as their changes during and after the COVID-19 restrictions. Survey data collected during the lockdown period have captured information about people’s ability to access green and blue spaces within urban BGI, inequalities in access, feelings, and values as well as needs and perceived pathways of future development of urban natural environment. In both cities, lockdowns limited access of people to green spaces which affected their mental and physical health. Survey results revealed that the quality, functionality, and location of open green spaces illustrated a disparity in distribution, meaning that in many cases several communities from particular neighborhoods suffered from limited access to BGI. Furthermore, in addition to analyzing perceptions and values of urban nature during the COVID-19 pandemic, some suggestions for improvement of urban BGI based on the survey responses are provided. Full article
(This article belongs to the Section Sustainable Urban and Rural Development)
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17 pages, 2675 KiB  
Article
Cogeneration Supporting the Energy Transition in the Italian Ceramic Tile Industry
by Lisa Branchini, Maria Chiara Bignozzi, Benedetta Ferrari, Barbara Mazzanti, Saverio Ottaviano, Marcello Salvio, Claudia Toro, Fabrizio Martini and Andrea Canetti
Sustainability 2021, 13(7), 4006; https://doi.org/10.3390/su13074006 - 3 Apr 2021
Cited by 15 | Viewed by 4985
Abstract
Ceramic tile production is an industrial process where energy efficiency management is crucial, given the high amount of energy (electrical and thermal) required by the production cycle. This study presents the preliminary results of a research project aimed at defining the benefits of [...] Read more.
Ceramic tile production is an industrial process where energy efficiency management is crucial, given the high amount of energy (electrical and thermal) required by the production cycle. This study presents the preliminary results of a research project aimed at defining the benefits of using combined heat and power (CHP) systems in the ceramic sector. Data collected from ten CHP installations allowed us to outline the average characteristics of prime movers, and to quantify the contribution of CHP thermal energy supporting the dryer process. The electric size of the installed CHP units resulted in being between 3.4 MW and 4.9 MW, with an average value of 4 MW. Data revealed that when the goal is to maximize the generation of electricity for self-consumption, internal combustion engines are the preferred choice due to higher conversion efficiency. In contrast, gas turbines allowed us to minimize the consumption of natural gas input to the spray dryer. Indeed, the fraction of the dryer thermal demand (between 600–950 kcal/kgH2O), covered by CHP discharged heat, is strictly dependent on the type of prime mover installed: lower values, in the range of 30–45%, are characteristic of combustion engines, whereas the use of gas turbines can contribute up to 77% of the process’s total consumption. Full article
(This article belongs to the Special Issue Industrial Energy Management and Sustainability)
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22 pages, 9567 KiB  
Article
The Importance of Stud Flanges Size and Shape on the Thermal Performance of Lightweight Steel Framed Walls
by Paulo Santos and Keerthan Poologanathan
Sustainability 2021, 13(7), 3970; https://doi.org/10.3390/su13073970 - 2 Apr 2021
Cited by 16 | Viewed by 3649
Abstract
Energy production still relies considerably on fossil fuels, and the building sector is a major player in the energy consumption market, mainly for space heating and cooling. Thermal bridges (TBs) in buildings are very relevant for the energy efficiency of buildings and may [...] Read more.
Energy production still relies considerably on fossil fuels, and the building sector is a major player in the energy consumption market, mainly for space heating and cooling. Thermal bridges (TBs) in buildings are very relevant for the energy efficiency of buildings and may have an impact on heating energy needs of up to 30%. Given the high thermal conductivity of steel, the relevance of TBs in lightweight steel framed (LSF) components could be even greater. No research was found in the literature for evaluating how important the size and shape of steel studs are on the thermal performance of LSF building elements, which is the main objective of this work. This assessment is performed for the internal partitions and exterior façade of load-bearing LSF walls. The accuracy of the numerical model used in the simulations was verified and validated by comparison experimental measurements. Three reference steel studs were considered, six stud flange lengths and four steel thicknesses were evaluated, and five flange indentation sizes and four indent filling materials were assessed, corresponding to a total of 246 modelled LSF walls. It was concluded that the R-value decreases when the flange length and the steel studs’ thickness increases, being that these variations are more significant for bigger flange sizes and for thicker steel studs. Additionally, it was found that a small indentation size (2.5 or 5 mm) is enough to provide a significant R-value increase and that it is preferable not to use any flange indentation filling material rather than using a poor performance one (recycled rubber). Full article
(This article belongs to the Special Issue Thermal Behavior and Energy Efficiency of Buildings)
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22 pages, 10136 KiB  
Article
Aiming Strategy on a Prototype-Scale Solar Receiver: Coupling of Tabu Search, Ray-Tracing and Thermal Models
by Benjamin Grange and Gilles Flamant
Sustainability 2021, 13(7), 3920; https://doi.org/10.3390/su13073920 - 1 Apr 2021
Cited by 10 | Viewed by 2489
Abstract
An aiming point strategy applied to a prototype-scale power tower is analyzed in this paper to define the operation conditions and to preserve the lifetime of the solar receiver developed in the framework of the Next-commercial solar power (CSP) H2020 project. This innovative [...] Read more.
An aiming point strategy applied to a prototype-scale power tower is analyzed in this paper to define the operation conditions and to preserve the lifetime of the solar receiver developed in the framework of the Next-commercial solar power (CSP) H2020 project. This innovative solar receiver involves the fluidized particle-in-tube concept. The aiming solution is compared to the case without the aiming strategy. Due to the complex tubular geometry of the receiver, results of the Tabu search for the aiming point strategy are combined with a ray-tracing software, and these results are then coupled with a simplified thermal model of the receiver to evaluate its performance. Daily and hourly aiming strategies are compared, and different objective normalized flux distributions are applied to quantify their influence on the receiver wall temperature distribution, thermal efficiency and particle outlet temperature. A gradual increase in the solar incident power on the receiver is analyzed in order to keep a uniform outlet particle temperature during the start-up. Results show that a tradeoff must be respected between wall temperature and particle outlet temperature. Full article
(This article belongs to the Special Issue Advances in Solar Thermal Energy)
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24 pages, 3007 KiB  
Article
Improvement of Self-Starting Capabilities of Vertical Axis Wind Turbines with New Design of Turbine Blades
by Samuel Mitchell, Iheanyichukwu Ogbonna and Konstantin Volkov
Sustainability 2021, 13(7), 3854; https://doi.org/10.3390/su13073854 - 31 Mar 2021
Cited by 27 | Viewed by 4462
Abstract
A lift-driven vertical axis wind turbine (VAWT) generates peak power when it is rotating at high tip-speed ratios (TSR), at which time the blades encounter angles of attack (AOA) over a small range from zero to 30 degrees. However, its ability to self-start [...] Read more.
A lift-driven vertical axis wind turbine (VAWT) generates peak power when it is rotating at high tip-speed ratios (TSR), at which time the blades encounter angles of attack (AOA) over a small range from zero to 30 degrees. However, its ability to self-start is dependent upon its performance at low TSRs, at which time the blades encounter a range of AOAs from zero to 180 degrees. A novel vented aerofoil is presented with the intention of improving the performance of a lift-driven VAWT at low TSRs without hampering the performance of the wind turbine at high TSRs. Computational fluid dynamics (CFD) simulation is used to predict the aerodynamic characteristics of a new vented aerofoil based on the well documented NACA0012 profile. Simulations are performed using the SST turbulence model. The results obtained show a reduction in the coefficient of tangential force (the force that generates torque on the wind turbine) at low AOAs (less than 90 degrees) of no more than 30%, while at high AOAs (more than 90 degrees) an improvement in the tangential force of over 100% is observed. Using a simple momentum based performance prediction model, these results suggest that this would lead to an increase in torque generation by a theoretical three-bladed VAWT of up to 20% at low TSRs and a minor reduction in coefficient of performance of up to 9% at TSR of 2 and closer to 1% at higher TSRs. Full article
(This article belongs to the Special Issue Design and Optimization of Renewable Energy Systems)
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34 pages, 2186 KiB  
Review
Survey on e-Powered Micro Personal Mobility Vehicles: Exploring Current Issues towards Future Developments
by Stefania Boglietti, Benedetto Barabino and Giulio Maternini
Sustainability 2021, 13(7), 3692; https://doi.org/10.3390/su13073692 - 26 Mar 2021
Cited by 87 | Viewed by 9194
Abstract
Nowadays, the diffusion of electric-powered micro Personal Mobility Vehicles (e-PMVs) worldwide—i.e., e-bikes, e-scooters, and self-balancing vehicles—has disrupted the urban transport sector. Furthermore, this topic has captured many scholars and practitioners’ interest due to multiple issues related to their use. Over the past five [...] Read more.
Nowadays, the diffusion of electric-powered micro Personal Mobility Vehicles (e-PMVs) worldwide—i.e., e-bikes, e-scooters, and self-balancing vehicles—has disrupted the urban transport sector. Furthermore, this topic has captured many scholars and practitioners’ interest due to multiple issues related to their use. Over the past five years, there has been strong growth in the publication of e-PMV studies. This paper reviews the existing literature by identifying several issues on the impact that e-PMVs produce from different perspectives. More precisely, by using the PRIMA’s methodological approach and well-known scientific repositories (i.e., Scopus, Web of Science, and Google Scholar), 90 studies between 2014 and 2020 were retrieved and analyzed. An overview and classification into endogenous issues (e.g., impact on transport and urban planning) and exogenous issues (e.g., impact on safety and the environment) are provided. While several issues are deeply investigated, the findings suggest that some others need many improvements. Therefore, the status quo of these studies is being assessed to support possible future developments. Full article
(This article belongs to the Special Issue Service Quality in Public Transport Systems and Personal Mobility Vehicles)
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30 pages, 15746 KiB  
Article
Applying PCA to Deep Learning Forecasting Models for Predicting PM2.5
by Sang Won Choi and Brian H. S. Kim
Sustainability 2021, 13(7), 3726; https://doi.org/10.3390/su13073726 - 26 Mar 2021
Cited by 37 | Viewed by 5849
Abstract
Fine particulate matter (PM2.5) is one of the main air pollution problems that occur in major cities around the world. A country’s PM2.5 can be affected not only by country factors but also by the neighboring country’s air quality factors. [...] Read more.
Fine particulate matter (PM2.5) is one of the main air pollution problems that occur in major cities around the world. A country’s PM2.5 can be affected not only by country factors but also by the neighboring country’s air quality factors. Therefore, forecasting PM2.5 requires collecting data from outside the country as well as from within which is necessary for policies and plans. The data set of many variables with a relatively small number of observations can cause a dimensionality problem and limit the performance of the deep learning model. This study used daily data for five years in predicting PM2.5 concentrations in eight Korean cities through deep learning models. PM2.5 data of China were collected and used as input variables to solve the dimensionality problem using principal components analysis (PCA). The deep learning models used were a recurrent neural network (RNN), long short-term memory (LSTM), and bidirectional LSTM (BiLSTM). The performance of the models with and without PCA was compared using root-mean-square error (RMSE) and mean absolute error (MAE). As a result, the application of PCA in LSTM and BiLSTM, excluding the RNN, showed better performance: decreases of up to 16.6% and 33.3% in RMSE and MAE values. The results indicated that applying PCA in deep learning time series prediction can contribute to practical performance improvements, even with a small number of observations. It also provides a more accurate basis for the establishment of PM2.5 reduction policy in the country. Full article
(This article belongs to the Section Environmental Sustainability and Applications)
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18 pages, 1204 KiB  
Review
Mobility as a Service and Public Transport: A Rapid Literature Review and the Case of Moovit
by Georgina Santos and Nikolay Nikolaev
Sustainability 2021, 13(7), 3666; https://doi.org/10.3390/su13073666 - 25 Mar 2021
Cited by 32 | Viewed by 9034
Abstract
Mobility as a Service (MaaS) is often proposed as a tool for achieving sustainable mobility and, in particular, increasing the share of public transport trips in cities. In this paper we conduct a rapid review of the literature on MaaS and, using Moovit [...] Read more.
Mobility as a Service (MaaS) is often proposed as a tool for achieving sustainable mobility and, in particular, increasing the share of public transport trips in cities. In this paper we conduct a rapid review of the literature on MaaS and, using Moovit as a case study, we explore the association between the popularity of searches in Google using the term “Moovit” and the share of workers that commute by public transport. The exercise focuses on metropolitan areas in the United States over the period 2010 to 2019. We find a positive correlation, and we speculate that metropolitan areas with pre-existing higher shares of workers commuting by public transport tend to be metropolitan areas where use of Moovit is more likely. Full article
(This article belongs to the Collection Sustainability in Urban Transportation Planning)
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20 pages, 40809 KiB  
Article
Life Cycle Assessment (LCA) of a Concentrating Solar Power (CSP) Plant in Tower Configuration with and without Thermal Energy Storage (TES)
by Gemma Gasa, Anton Lopez-Roman, Cristina Prieto and Luisa F. Cabeza
Sustainability 2021, 13(7), 3672; https://doi.org/10.3390/su13073672 - 25 Mar 2021
Cited by 45 | Viewed by 10781
Abstract
Despite the big deployment of concentrating solar power (CSP) plants, their environmental evaluation is still a pending issue. In this paper, a detailed life cycle assessment (LCA) of a CSP tower plant with molten salts storage in a baseload configuration is carried out [...] Read more.
Despite the big deployment of concentrating solar power (CSP) plants, their environmental evaluation is still a pending issue. In this paper, a detailed life cycle assessment (LCA) of a CSP tower plant with molten salts storage in a baseload configuration is carried out and compared with a reference CSP plant without storage. Results show that the plant with storage has a lower environmental impact due to the lower operational impact. The dependence on grid electricity in a CSP tower plant without storage increases its operation stage impact. The impact of the manufacturing and disposal stage is similar in both plants. When analyzed in detail, the solar field system and the thermal energy storage (TES) and heat transfer fluid (HTF) systems are the ones with higher impact. Within the storage system, the molten salts are those with higher impact. Therefore, in this study the impact of the origin of the salts is evaluated, showing that when the salts come from mines their impact is lower than when they are synthetized. Results show that storage is a key element for CSP plants not only to ensure dispatchability but also to reduce their environmental impact. Full article
(This article belongs to the Special Issue Advances in Renewable Energy Technologies for Distributed Generation)
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21 pages, 451 KiB  
Review
Vertically Integrated Supply Chain of Batteries, Electric Vehicles, and Charging Infrastructure: A Review of Three Milestone Projects from Theory of Constraints Perspective
by Michael Naor, Alex Coman and Anat Wiznizer
Sustainability 2021, 13(7), 3632; https://doi.org/10.3390/su13073632 - 24 Mar 2021
Cited by 19 | Viewed by 41135
Abstract
This research utilizes case study methodology based on longitudinal interviews over a decade coupled with secondary data sources to juxtapose Tesla with two high-profile past mega-projects in the electric transportation industry, EV-1 and Better Place. The theory of constraints serves as a lens [...] Read more.
This research utilizes case study methodology based on longitudinal interviews over a decade coupled with secondary data sources to juxtapose Tesla with two high-profile past mega-projects in the electric transportation industry, EV-1 and Better Place. The theory of constraints serves as a lens to identify production and market bottlenecks for the dissemination of electric vehicles. The valuable lessons learned from EV1 failure and Better Place bankruptcy paved the way for Tesla’s operations strategy to build gigafactories which bears a resemblance to Ford T mass production last century. Specifically, EV1 relied on external suppliers to develop batteries, while Better Place was dependent on a single manufacturer to build cars uniquely compatible with its charging infrastructure, whereas Tesla established a closed-loop, green, vertically integrated supply chain consisting of batteries, electric cars and charging infrastructure to meet its customers evolving needs. The analysis unveils several limitations of the Tesla business model which can impede its worldwide expansion, such as utility grid overload and a shortage of raw material, which Tesla strives to address by innovating advanced batteries and further extending its vertically integrated supply chain to the mining industry. The study concludes by sketching fruitful possible avenues for future research. Full article
(This article belongs to the Special Issue Innovative Business Transaction, Product Development or Service Design for Advancement of Sustainable Transportation in the 21st Century)
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20 pages, 700 KiB  
Article
Different Levels of Smart and Sustainable Cities Construction Using e-Participation Tools in European and Central Asian Countries
by Laura Alcaide Muñoz and Manuel Pedro Rodríguez Bolívar
Sustainability 2021, 13(6), 3561; https://doi.org/10.3390/su13063561 - 23 Mar 2021
Cited by 30 | Viewed by 5424
Abstract
Cities are developing strategies to deal with the complex challenges of global change and sustainability. These initiatives have involved the implementation of Information and Communication Technologies (ICTs) as a good driver for achieving sustainability because digital transformation can boost sustainable development strategies, providing [...] Read more.
Cities are developing strategies to deal with the complex challenges of global change and sustainability. These initiatives have involved the implementation of Information and Communication Technologies (ICTs) as a good driver for achieving sustainability because digital transformation can boost sustainable development strategies, providing opportunities to accelerate transformation. Smart City (SC) models built on empowering people in making public decisions favor access to sustainable development solutions based on knowledge and innovation. Nonetheless, SC experiences around the world denote divergent conceptions of SCs which could lead to different SCs construction. It deserves a more thorough understanding of the nature of collaboration in different settings. Therefore, this paper contributes to the debate on the different uses of ICTs in SCs construction in developing vs. developed countries, by examining the use of ICTs for creating collaborative environments in a sample of SCs in different countries, depending on their economic level, and seeking to identify differences in the objectives pursued by city governments with the use of these technologies. To achieve this aim, e-participation platforms, apps or social media platforms (European and Central Asia SCs) are examined for identifying SCs construction differences between developed vs. developing countries. The findings of this paper put an emphasis on the need for taking into account the differences among SCs in developed vs. developing countries when raking or when performance measurement is designed, because the assessment should be tailored to the cities’ particular visions and priorities for achieving their objectives. Full article
(This article belongs to the Special Issue Building Smart and Sustainable Cities: Emerging Technologies and Innovation for Digital-Era Governance and Long-Term Impacts)
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17 pages, 3424 KiB  
Article
Optimal Operation of a Hydrogen Storage and Fuel Cell Coupled Integrated Energy System
by Oscar Utomo, Muditha Abeysekera and Carlos E. Ugalde-Loo
Sustainability 2021, 13(6), 3525; https://doi.org/10.3390/su13063525 - 22 Mar 2021
Cited by 42 | Viewed by 5446
Abstract
Integrated energy systems have become an area of interest as with growing energy demand globally, means of producing sustainable energy from flexible sources is key to meet future energy demands while keeping carbon emissions low. Hydrogen is a potential solution for providing flexibility [...] Read more.
Integrated energy systems have become an area of interest as with growing energy demand globally, means of producing sustainable energy from flexible sources is key to meet future energy demands while keeping carbon emissions low. Hydrogen is a potential solution for providing flexibility in the future energy mix as it does not emit harmful gases when used as an energy source. In this paper, an integrated energy system including hydrogen as an energy vector and hydrogen storage is studied. The system is used to assess the behaviour of a hydrogen production and storage system under different renewable energy generation profiles. Two case studies are considered: a high renewable energy generation scenario and a low renewable energy generation scenario. These provide an understanding of how different levels of renewable penetration may affect the operation of an electrolyser and a fuel cell against an electricity import/export pricing regime. The mathematical model of the system under study is represented using the energy hub approach, with system optimisation through linear programming conducted via MATLAB to minimise the total operational cost. The work undertaken showcases the unique interactions the fuel cell has with the hydrogen storage system in terms of minimising grid electricity import and exporting stored hydrogen as electricity back to the grid when export prices are competitive. Full article
(This article belongs to the Special Issue Sustainable Hydrogen Energy Systems: Electric Applications)
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16 pages, 1950 KiB  
Article
The Unsustainable Use of Sand: Reporting on a Global Problem
by Walter Leal Filho, Julian Hunt, Alexandros Lingos, Johannes Platje, Lara Werncke Vieira, Markus Will and Marius Dan Gavriletea
Sustainability 2021, 13(6), 3356; https://doi.org/10.3390/su13063356 - 18 Mar 2021
Cited by 81 | Viewed by 18951
Abstract
Sand is considered one of the most consumed natural resource, being essential to many industries, including building construction, electronics, plastics, and water filtration. This paper assesses the environmental impact of sand extraction and the problems associated with its illegal exploitation. The analysis indicates [...] Read more.
Sand is considered one of the most consumed natural resource, being essential to many industries, including building construction, electronics, plastics, and water filtration. This paper assesses the environmental impact of sand extraction and the problems associated with its illegal exploitation. The analysis indicates that extracting sand at a greater rate than that at which it is naturally replenished has adverse consequences for fauna and flora. Further, illicit mining activities compound environmental damages and result in conflict, the loss of taxes/royalties, illegal work, and losses in the tourism industry. As sea-level rise associated with climate change threatens coastal areas, sand in coastal areas will play an increasingly greater role in determining the amount of damage from floods and erosion. The present analysis points to the need for swift action to regulate sand mining, monitoring, law enforcement, and international cooperation. Full article
(This article belongs to the Special Issue Environmental Impact and Nature Conservation)
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18 pages, 2160 KiB  
Article
Exploring the Potential of a Gamified Approach to Reduce Energy Use and Carbon Emissions in the Household Sector
by Marta Gangolells, Miquel Casals, Marcel Macarulla and Núria Forcada
Sustainability 2021, 13(6), 3380; https://doi.org/10.3390/su13063380 - 18 Mar 2021
Cited by 14 | Viewed by 3583
Abstract
This paper analyzes the impact of an innovative approach based on gamification to promote reduced energy consumption in social housing. The game was developed and validated under the auspices of the EU-funded project EnerGAware-Energy Game for Awareness of energy efficiency in social housing [...] Read more.
This paper analyzes the impact of an innovative approach based on gamification to promote reduced energy consumption in social housing. The game was developed and validated under the auspices of the EU-funded project EnerGAware-Energy Game for Awareness of energy efficiency in social housing communities in an affordable housing pilot located in Plymouth (United Kingdom). The results showed that the future exploitation of the game holds important energy- and emissions-saving potential. Assuming that the game is distributed freely by European energy providers to their domestic end-users, the game was found to be able to save more than 48.9 secondary terawatt-hours per year (TWhs) and 18.8 million tons of CO2e annually, contributing up to around 8% to the target set for the European buildings sector to keep global warming under 2 °C. The results also showed that the game is highly feasible from the energy point of view, even when we consider the energy consumed upstream, due to its low cumulative energy demand and its potential for household energy reduction. The results of this research provide helpful information for private and public stakeholders, as they contribute to determining the sustainability of promoting energy saving through gaming. Full article
(This article belongs to the Special Issue Next Energy Efficiency Solutions for Sustainable Buildings)
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20 pages, 1493 KiB  
Review
City Digital Twin Potentials: A Review and Research Agenda
by Ehab Shahat, Chang T. Hyun and Chunho Yeom
Sustainability 2021, 13(6), 3386; https://doi.org/10.3390/su13063386 - 18 Mar 2021
Cited by 333 | Viewed by 24036
Abstract
The city digital twin is anticipated to accurately reflect and affect the city’s functions and processes to enhance its realization, operability, and management. Although research on the city digital twin is still in its infancy, the advancement of the digital twin technology is [...] Read more.
The city digital twin is anticipated to accurately reflect and affect the city’s functions and processes to enhance its realization, operability, and management. Although research on the city digital twin is still in its infancy, the advancement of the digital twin technology is growing fast and providing viable contributions to augmenting smart city developments. This study reviews the literature to identify the current and prospective potentials and challenges of digital twin cities. A research agenda is also proposed to guide future research on the city digital twincity digital twin to reach the utmost level of a comprehensive and complete city digital twin. Enhancing the efficiency of data processing, promoting the inclusion of socio-economic components of the city, and developing mutual integration between the two counterparts of the digital twin are proposed to be the future research directions to achieve and utilize a completely mirrored city digital twin. Full article
(This article belongs to the Special Issue Smart City Development and Sustainability)
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25 pages, 4752 KiB  
Article
Innovative Box-Wing Aircraft: Emissions and Climate Change
by Andrea Luca Tasca, Vittorio Cipolla, Karim Abu Salem and Monica Puccini
Sustainability 2021, 13(6), 3282; https://doi.org/10.3390/su13063282 - 16 Mar 2021
Cited by 32 | Viewed by 8661
Abstract
The PARSIFAL project (Prandtlplane ARchitecture for the Sustainable Improvement of Future AirpLanes) aims to promote an innovative box-wing aircraft: the PrandtlPlane. Aircraft developed adopting this configuration are expected to achieve a payload capability higher than common single aisle analogues (e.g., Airbus 320 and [...] Read more.
The PARSIFAL project (Prandtlplane ARchitecture for the Sustainable Improvement of Future AirpLanes) aims to promote an innovative box-wing aircraft: the PrandtlPlane. Aircraft developed adopting this configuration are expected to achieve a payload capability higher than common single aisle analogues (e.g., Airbus 320 and Boeing 737 families), without any increase in the overall dimensions. We estimated the exhaust emissions from the PrandtlPlane and compared the corresponding impacts to those of a conventional reference aircraft, in terms of Global Warming Potential (GWP) and Global Temperature Potential (GTP), on two time-horizons and accounted for regional sensitivity. We considered carbon dioxide, carbonaceous and sulphate aerosols, nitrogen oxides and related ozone production, methane degradation and nitrate aerosols formation, contrails, and contrail cirrus. Overall, the introduction of the PrandtlPlane is expected to bring a considerable reduction of climate change in all the source regions considered, on both the time-horizons examined. Moreover, fuel consumption is expected to be reduced by 20%, as confirmed through high-fidelity Computational Fluid Dynamics (CFD) simulations. Sensitivity of data, models, and metrics are detailed. Impact reduction and mitigation strategies are discussed, as well as the gaps to be addressed in order to develop a comprehensive Life Cycle Assessment on aircraft emissions. Full article
(This article belongs to the Section Sustainable Transportation)
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15 pages, 2094 KiB  
Article
Verifying the Effectiveness of Sports Event Policies for a City’s Sustainable Growth: Focusing on the Multiple Effects
by Jae-Gu Yu, Yun-Duk Jeong and Suk-Kyu Kim
Sustainability 2021, 13(6), 3285; https://doi.org/10.3390/su13063285 - 16 Mar 2021
Cited by 5 | Viewed by 3692
Abstract
This article presents empirical evidence that suggests that there are multiple effects of local government sports event hosting policies. This study is predicated on the notion that the attraction of sports events is a feature of city-level policies. The empirical analysis used a [...] Read more.
This article presents empirical evidence that suggests that there are multiple effects of local government sports event hosting policies. This study is predicated on the notion that the attraction of sports events is a feature of city-level policies. The empirical analysis used a multiple effects model, and the research employed a dual model approach: (a) a sponsorship effect model and (b) a tourism effect model. A questionnaire was administered online, and 383 cases were used for data processing. Confirmatory factor analysis and structural equation modeling were performed using SPSS 25.0 and AMOS 25.0. (a) In the “business model”, it was confirmed that event satisfaction affected sustainable purchase intention only through the sponsor’s social image. (b) The “tourism model” confirmed that event satisfaction affected the intention to engage in positive word of mouth to recommend the destination through both forming a psychological attachment and experiencing emotional satisfaction. Among the event satisfaction factors, service satisfaction was identified as more important than facility satisfaction. As shown by the above results, satisfaction with sports events had simultaneous effects on the persistence of the sponsorship effects model and the persistence of tourism effects. The study concluded that attractive sports events promoted sustainable urban growth. Full article
(This article belongs to the Section Sustainable Urban and Rural Development)
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8 pages, 2090 KiB  
Article
Research of the Behavior of Clay Materials with Double Porosity
by Hynek Lahuta and Luis Andrade Pais
Sustainability 2021, 13(6), 3219; https://doi.org/10.3390/su13063219 - 15 Mar 2021
Cited by 2 | Viewed by 2072
Abstract
This contribution presents results from a series of compression and undrained triaxial tests to study the mechanical behavior of dump clay from the north of Bohemia. The use of these materials as a foundation for construction can’t be achieved without the adoption of [...] Read more.
This contribution presents results from a series of compression and undrained triaxial tests to study the mechanical behavior of dump clay from the north of Bohemia. The use of these materials as a foundation for construction can’t be achieved without the adoption of some precautions. This comes from embankment, formed by digging the ground (altered claystone), up to the level of coal mining which is in a sub horizontal stratigraphic layer. A potential static liquefaction behavior was observed in undrained tests for high confinement stress. A structural collapse was noticed with the results obtained in the triaxial test. This collapse is characterized by an unexpected large decrease in deviator and mean effective stress. The soils formed have strength properties that are potentially dangerous. These concepts can improve the use of these kinds of soils in geotechnical engineering work. It continues and expands the results obtained in previous research, especially the future problematic use of these materials as the foundation soil for line or building structures. Full article
(This article belongs to the Special Issue New Environmental, Economic and Social Challenges for Raw Materials Supply: Sustainable Mining and Extractive Waste Exploitation)
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23 pages, 7525 KiB  
Article
Sustainable Urban Greening and Cooling Strategies for Thermal Comfort at Pedestrian Level
by Maurizio Detommaso, Antonio Gagliano, Luigi Marletta and Francesco Nocera
Sustainability 2021, 13(6), 3138; https://doi.org/10.3390/su13063138 - 12 Mar 2021
Cited by 48 | Viewed by 5492
Abstract
The increase of the urban warming phenomenon all over the world is gaining increasing attention from scientists as well as planners and policymakers due to its adverse effects on energy consumption, health, wellbeing, and air pollution. The protection of urban areas from the [...] Read more.
The increase of the urban warming phenomenon all over the world is gaining increasing attention from scientists as well as planners and policymakers due to its adverse effects on energy consumption, health, wellbeing, and air pollution. The protection of urban areas from the outdoor warming phenomenon is one of the challenges that policy and governments have to tackle as soon as possible and in the best possible way. Among the urban heat island mitigation techniques, cool materials and urban greening are identified as the most effective solutions in reducing the urban warming phenomenon. The effects produced by the adoption of cool materials and urban forestation on the urban microclimate were investigated through a computational fluid-dynamic (CFD) model. The CFD model was calibrated and validated thanks to experimental surveys within the Catania University campus area. The urban microclimate thermal comfort analysis and assessment were carried out with the Klima–Michel Model (KMM) and Munich Energy Balance Model for Individuals (MEMI). In particular, three scenarios were performed: cool, low, and high levels of urban greening. The cool scenario, although it produces air temperature at around 1.00 °C, determines the worst condition of outdoor thermal comfort, especially at the pedestrian level. On the contrary, a high level of urban greening, obtained by the extensive green roofs together with an urban forestation, guarantees the wellbeing of pedestrians, showing more convenient values of PMV and PET. Full article
(This article belongs to the Special Issue Adaptation to Global Change: Modeling and Decision Support Tools in Urban Planning)
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23 pages, 3021 KiB  
Article
Determinants of Sustainability Reporting in the Present Institutional Context: The Case of Port Managing Bodies
by Magali Geerts, Michaël Dooms and Lara Stas
Sustainability 2021, 13(6), 3148; https://doi.org/10.3390/su13063148 - 12 Mar 2021
Cited by 30 | Viewed by 5722
Abstract
Research on the practice of sustainability reporting that is specifically focused on the approach applied by port authorities (or port managing bodies—PMBs) and based on surveys as a data collection method, is very limited. Most research consists of single-case studies, only partly covers [...] Read more.
Research on the practice of sustainability reporting that is specifically focused on the approach applied by port authorities (or port managing bodies—PMBs) and based on surveys as a data collection method, is very limited. Most research consists of single-case studies, only partly covers the different dimensions related to the implementation of sustainability reporting, or is based on content analysis. This paper offers a multidimensional approach of the concept of sustainability reporting based on a global survey yielding 97 complete and valid answers of PMBs. A binomial logistic regression has been conducted to identify those organizational characteristics, whether or not under the control of the PMB, that have the largest explanatory power when it comes to the adoption of the practice of sustainability reporting. The research results present new variables compared to the findings of previous studies, such as proximity to a city, the history of data gathering, and the presence of environmental/social certifications. Furthermore, this paper also investigates how these organizational characteristics are interlinked with external, contextual forces by making use of Institutional Theory. By combining organizational characteristics with information on the institutional environment in which the PMB operates, a more complete image is obtained. The results of this analysis show that myriad different institutional pressures are in play when it comes to having influence over the decision making of PMBs with regard to the adoption of sustainability reporting. Furthermore, several prominent associations between one of the isomorphisms and certain organizational characteristics can be observed. Full article
(This article belongs to the Special Issue Port Governance)
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23 pages, 32536 KiB  
Article
Hydrologic Performance of an Extensive Green Roof under Intense Rain Events: Results from a Rain-Chamber Simulation
by Elena Giacomello and Jacopo Gaspari
Sustainability 2021, 13(6), 3078; https://doi.org/10.3390/su13063078 - 11 Mar 2021
Cited by 10 | Viewed by 3436
Abstract
The water storage capacity of a green roof generates several benefits for the building conterminous environment. The hydrologic performance is conventionally expressed by the runoff coefficient, according to international standards and guidelines. The runoff coefficient is a dimensionless number and defines the water [...] Read more.
The water storage capacity of a green roof generates several benefits for the building conterminous environment. The hydrologic performance is conventionally expressed by the runoff coefficient, according to international standards and guidelines. The runoff coefficient is a dimensionless number and defines the water retention performance over a long period. At the scale of single rain events, characterized by varying intensity and duration, the reaction of the green roof is scarcely investigated. The purpose of this study is to highlight how an extensive green roof—having a supposed minimum water performance, compared to an intensive one—responds to real and repetitive rain events, simulated in a rain chamber with controlled rain and runoff data. The experiment provides, through cumulative curve graphs, the behavior of the green roof sample during four rainy days. The simulated rain events are based on a statistical study (summarized in the paper) of 25 years of rain data for a specific location in North Italy characterized by an average rain/year of 1100 mm. The results prove the active response of the substrate, although thin and mineral, and quick draining, in terms of water retention and detention during intense rain events. The study raises questions about how to better express the water performance of green roofs. Full article
(This article belongs to the Section Environmental Sustainability and Applications)
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20 pages, 3581 KiB  
Article
Adaptive Management of Malkumba-Coongie Lakes Ramsar Site in Arid Australia—A Free Flowing River and Wetland System
by Richard T. Kingsford, Craig A. McLoughlin, Robert Brandle, Gilad Bino, Bernie Cockayne, David Schmarr, Travis Gotch, Vol Norris and Justin McCann
Sustainability 2021, 13(6), 3043; https://doi.org/10.3390/su13063043 - 10 Mar 2021
Cited by 6 | Viewed by 5928
Abstract
The Malkumba-Coongie Lakes Ramsar Site has extensive terrestrial and freshwater ecosystems (largest Ramsar Site in Oceania, 2,178,952 ha, designated in 1987), including freshwater and salt lakes, lignum swamps and river channels in central Australia. It is supplied by Cooper Creek, a free-flowing Lake [...] Read more.
The Malkumba-Coongie Lakes Ramsar Site has extensive terrestrial and freshwater ecosystems (largest Ramsar Site in Oceania, 2,178,952 ha, designated in 1987), including freshwater and salt lakes, lignum swamps and river channels in central Australia. It is supplied by Cooper Creek, a free-flowing Lake Eyre Basin river system. The area includes pastoral leases (97% of site grazed, including a regional conservation reserve (35%)) and a National Park (3%), with the largest oil and gas production field in Australia. We developed a Strategic Adaptive Management (SAM) Plan, linking science, monitoring and management of this social-ecological system, involving stakeholders and workshops. This involved developing a shared vision and hierarchy of objectives linked to management actions and identified outputs and outcomes. We exemplify this approach with explicit and measurable end-points (thresholds of potential concern) culminating from low level objectives for fish communities, particularly the alien sleepy cod Oxyeleotris lineolata. We describe this framework, highlighting the benefits in prioritizing management actions and monitoring in collaboration with a diverse range of stakeholders, driving adaptive feedback for learning. The whole approach is aimed at successfully achieving mutually agreed management objectives and the vision to maintain the ecological character of the Malkumba-Coongie Lakes Ramsar Site. Full article
(This article belongs to the Special Issue Durable Protections for Free-Flowing Rivers)
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12 pages, 3269 KiB  
Article
Load Resistance Optimization of a Broadband Bistable Piezoelectric Energy Harvester for Primary Harmonic and Subharmonic Behaviors
by Sungryong Bae and Pilkee Kim
Sustainability 2021, 13(5), 2865; https://doi.org/10.3390/su13052865 - 6 Mar 2021
Cited by 6 | Viewed by 2578
Abstract
In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the [...] Read more.
In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations. Full article
(This article belongs to the Section Energy Sustainability)
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16 pages, 2320 KiB  
Article
The Sustainability of Thailand’s Protected-Area System under Climate Change
by Nirunrut Pomoim, Robert J. Zomer, Alice C. Hughes and Richard T. Corlett
Sustainability 2021, 13(5), 2868; https://doi.org/10.3390/su13052868 - 6 Mar 2021
Cited by 11 | Viewed by 4182
Abstract
Protected areas are the backbone of biodiversity conservation but vulnerable to climate change. Thailand has a large and well-planned protected area system, covering most remaining natural vegetation. A statistically derived global environmental stratification (GEnS) was used to predict changes in bioclimatic conditions across [...] Read more.
Protected areas are the backbone of biodiversity conservation but vulnerable to climate change. Thailand has a large and well-planned protected area system, covering most remaining natural vegetation. A statistically derived global environmental stratification (GEnS) was used to predict changes in bioclimatic conditions across the protected area system for 2050 and 2070, based on projections from three CMIP5 earth system models and two representative concentration pathways (RCPs). Five bioclimatic zones were identified composed of 28 strata. Substantial spatial reorganization of bioclimates is projected in the next 50 years, even under RCP2.6, while under RCP8.5 the average upward shift for all zones by 2070 is 328–483 m and the coolest zone disappears with two models. Overall, 7.9–31.0% of Thailand’s land area will change zone by 2070, and 31.7–90.2% will change stratum. The consequences for biodiversity are less clear, particularly in the lowlands where the existing vegetation mosaic is determined largely by factors other than climate. Increasing connectivity of protected areas along temperature and rainfall gradients would allow species to migrate in response to climate change, but this will be difficult in much of Thailand. For isolated protected areas and species that cannot move fast enough, more active, species-specific interventions may be necessary. Full article
(This article belongs to the Section Air, Climate Change and Sustainability)
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23 pages, 1523 KiB  
Article
The Constrained Air Transport Energy Paradigm in 2021
by Abel Jiménez-Crisóstomo, Luis Rubio-Andrada, María Soledad Celemín-Pedroche and María Escat-Cortés
Sustainability 2021, 13(5), 2830; https://doi.org/10.3390/su13052830 - 5 Mar 2021
Cited by 7 | Viewed by 4291
Abstract
The increasing relevance of air transport as a contributor to climate change requires the development of emissions reduction technologies in a socio-economic and cultural context, where demand and air traffic have traditionally held sustained growth rates. However, the irruption of COVID-19 in 2020 [...] Read more.
The increasing relevance of air transport as a contributor to climate change requires the development of emissions reduction technologies in a socio-economic and cultural context, where demand and air traffic have traditionally held sustained growth rates. However, the irruption of COVID-19 in 2020 has had an enormous negative impact on air travel demand and traffic volumes. Coincidentally, during 2020, new technology proposals for emissions reduction based on use of hydrogen and synthetic fuels have emerged from the aviation stake holders. By following a novel approach connecting the analysis of expectations of technology developments and their deployment into the fleet to market constraints, this study discusses how, even considering the new technology proposals and even if the COVID-19 has led to a completely different scenario in tourism and aviation, the air transport energy paradigm will remain unchanged in the upcoming decades as a consequence of market constraints, aircraft complexity, compliance with safety requirements, and extended life cycles. In this frame, aviation needs to keep on pursuing the abatement of its emissions while managing social expectations in a realistic manner and leaning on compensation schemes to achieve emissions contention while new technologies become serviceable in the longer term. Full article
(This article belongs to the Special Issue The Future of Sustainable Mobility Air Transport Systems: Challenges and Approaches)
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19 pages, 3403 KiB  
Article
Sustainability Assessment of Intensified Forestry—Forest Bioenergy versus Forest Biodiversity Targeting Forest Birds
by Ulla Mörtberg, Xi-Lillian Pang, Rimgaudas Treinys, Renats Trubins and Gintautas Mozgeris
Sustainability 2021, 13(5), 2789; https://doi.org/10.3390/su13052789 - 4 Mar 2021
Cited by 5 | Viewed by 3127
Abstract
Intensified forestry can be seen as a solution to climate change mitigation and securing energy supply, increasing the production of forest bioenergy feedstock as a substitution for fossil fuels. However, it may come with detrimental impacts on forest biodiversity, especially related to older [...] Read more.
Intensified forestry can be seen as a solution to climate change mitigation and securing energy supply, increasing the production of forest bioenergy feedstock as a substitution for fossil fuels. However, it may come with detrimental impacts on forest biodiversity, especially related to older forests. The aim of this study was to assess the sustainability of intensified forestry from climate-energy and biodiversity perspectives, targeting forest bird species. For this purpose, we applied the Landscape simulation and Ecological Assessment (LEcA) tool to the study area of Lithuania, having high ambitions for renewables and high forest biodiversity. With LEcA, we simulated forest growth and management for 100 years with two forest management strategies: Business As Usual (BAU) and Intensive forestry (INT), the latter with the purpose to fulfil renewable energy goals. With both strategies, the biomass yields increased well above the yields of the reference year, while the biodiversity indicators related to forest bird habitat to different degrees show the opposite, with lower levels than for the reference year. Furthermore, Strategy INT resulted in small-to-no benefits in the long run concerning potential biomass harvesting, while substantially affecting the biodiversity indicators negatively. The model results have the potential to inform policy and forest management planning concerning several sustainability goals simultaneously. Full article
(This article belongs to the Special Issue Integrated Sustainability Assessment of Forest Bioenergy Options)
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17 pages, 3915 KiB  
Article
Implementation of a Stable Solar-Powered Microgrid Testbed for Remote Applications
by Hossein Saberi, Hamidreza Nazaripouya and Shahab Mehraeen
Sustainability 2021, 13(5), 2707; https://doi.org/10.3390/su13052707 - 3 Mar 2021
Cited by 3 | Viewed by 2069
Abstract
An intrinsically stable microgrid, operated by inverter-interfaced distributed energy resources (I-DERs) is introduced in this paper. The microgrid is built upon a systematic design method, which is adapted from the operation of the synchronous machine (SM). The proposed method analogizes the dynamics of [...] Read more.
An intrinsically stable microgrid, operated by inverter-interfaced distributed energy resources (I-DERs) is introduced in this paper. The microgrid is built upon a systematic design method, which is adapted from the operation of the synchronous machine (SM). The proposed method analogizes the dynamics of the dc-link in I-DERs to the rotor dynamics in synchronous generators (SGs) and utilizes the capacitor as energy storage. Thus, the proposed mechanism relaxes battery usage for frequency control, and by using the capacitive stored energy, provides a high fault ride-through capability, which is suitable for both on-grid and off-grid applications. Based on stability analysis of the SG and the dynamic state matrix eigenvalues for multimachine power system, the dc-link capacitor of I-DERs is characterized in the context of microgrid. The dc-link capacitor stores kinetic energy similar to the rotor of the SG and provides inertia in transients without the need of battery storage. The inverter angle responds to the change of the dc link voltage (energy). The dc-link voltage is then controlled similar to the field control pertaining to the SG. Finally, a governor-like mechanism is applied to maintain dc-link voltage stability. Simulation and experimental results are provided to show the effectiveness of the proposed design mechanisms. Full article
(This article belongs to the Special Issue Innovative Solutions for Integration of Distributed Energy Resources)
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20 pages, 7731 KiB  
Article
Climate-Responsive Green-Space Design Inspired by Traditional Gardens: Microclimate and Human Thermal Comfort of Japanese Gardens
by Lihua Cui, Christoph D. D. Rupprecht and Shozo Shibata
Sustainability 2021, 13(5), 2736; https://doi.org/10.3390/su13052736 - 3 Mar 2021
Cited by 14 | Viewed by 5225
Abstract
Urban green spaces can provide relaxation, exercise, social interaction, and many other benefits for their communities, towns, and cities. However, green spaces in hot and humid regions risk being underutilized by residents unless thermal environments are designed to be sufficiently comfortable. Understanding what [...] Read more.
Urban green spaces can provide relaxation, exercise, social interaction, and many other benefits for their communities, towns, and cities. However, green spaces in hot and humid regions risk being underutilized by residents unless thermal environments are designed to be sufficiently comfortable. Understanding what conditions are needed for comfortable outdoor spaces, particularly how people feel in regard to their thermal environment, is vital in designing spaces for public use. Traditional gardens are excellent examples of successful microclimate design from which we can learn, as they are developed over the generations through observation and modification. This study analyzed how Japanese gardens affect people’s thermal stress on extremely hot summer days. Meteorological data was collected in three Japanese gardens, and human thermal comfort was evaluated through physiological equivalent temperature (PET). Statistical analysis examined the relationship between spatial configurations of the gardens and thermal comfort. Our study revealed that Japanese gardens can efficiently ameliorate thermal stress. Spatial analysis showed that garden elements affect thermal comfort variously depending on time of the day and spatial distribution. Full article
(This article belongs to the Special Issue Urban Green Infrastructure (UGI): Biodiversity, Ecosystem Services and Human Well-Being)
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15 pages, 705 KiB  
Article
An Integrated Approach of Multi-Criteria Decision-Making and Grey Theory for Evaluating Urban Public Transportation Systems
by Ahmad Alkharabsheh, Sarbast Moslem, Laila Oubahman and Szabolcs Duleba
Sustainability 2021, 13(5), 2740; https://doi.org/10.3390/su13052740 - 3 Mar 2021
Cited by 59 | Viewed by 6025
Abstract
Improving the local urban transport system’s quality is often seen as one of the critical points for the government and the local operator. An amelioration of the system can improve users’ satisfaction and attract new users while simultaneously decreasing traffic congestion and pollution. [...] Read more.
Improving the local urban transport system’s quality is often seen as one of the critical points for the government and the local operator. An amelioration of the system can improve users’ satisfaction and attract new users while simultaneously decreasing traffic congestion and pollution. Efficient methodologies are required to achieve sustainable development regarding complex issues associated with traffic congestion and pollution. In this study, we propose using the analytic hierarchy process (AHP) grey values to overcome the limitations of the uncertainty in the classical AHP approach. The presented grey-AHP model assumes an efficient contrivance to facilitate the public transport system’s supply quality evaluation, especially when respondents are non-experts. Finally, we estimate and rank the public transport system’s supply quality criteria by adopting the proposed model for a real-world case study (Amman city, Jordan). The study’s outcome shows the effectiveness and the applicability of the developed approach for enhancing the quality of the public transport system. Full article
(This article belongs to the Collection Sustainability in Urban Transportation Planning)
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19 pages, 827 KiB  
Article
Adopting Multiactor Multicriteria Analysis for the Evaluation of Energy Scenarios
by Sebastian Schär and Jutta Geldermann
Sustainability 2021, 13(5), 2594; https://doi.org/10.3390/su13052594 - 1 Mar 2021
Cited by 14 | Viewed by 3661
Abstract
The assessment of future options and pathways for sustainable energy systems requires considering multiple techno-economic, ecological and social issues. Multicriteria analysis methods, which are useful tools that aid decision processes involving various and even conflicting qualitative and quantitative criteria, could support such comprehensive [...] Read more.
The assessment of future options and pathways for sustainable energy systems requires considering multiple techno-economic, ecological and social issues. Multicriteria analysis methods, which are useful tools that aid decision processes involving various and even conflicting qualitative and quantitative criteria, could support such comprehensive analyses. With regard to energy policies, the key actors and stakeholders’ acceptance of emerging and innovative technologies for generating, converting and storing electricity, heat and fuels is crucial for their future implementation. The multiactor multicriteria (MAMCA) methodology was developed to involve stakeholders with vastly different views and objectives when addressing complex societal problems. We extend the MAMCA methodology to include the outranking approach PROMETHEE, which allows us to explicitly consider the stakeholders’ objectives in the evaluation process. The MAMCA method with PROMETHEE is applied to a case study of four different transition pathways of providing electricity to a bioenergy village in Germany. The explicit mapping at hand of an illustrative case study could help researchers and decision makers greatly in the assessment of pathways for sustainable energy systems; it is also applicable in other contexts requiring extensive stakeholder involvement and where qualitative and quantitative criteria are to be considered simultaneously. The detailed sensitivity analysis provided by the extension of the MAMCA method with PROMETHEE not only reveals the stakeholders’ crucial trade-offs when allowing each stakeholder group to develop its own set of criteria and weights but also indicates compromise options. Full article
(This article belongs to the Special Issue Analyzing Development Paths of Emerging Energy Technologies)
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20 pages, 1997 KiB  
Article
Social Sustainability of Compact Neighbourhoods Evidence from London and Berlin
by M. Reza Shirazi and Ramin Keivani
Sustainability 2021, 13(4), 2340; https://doi.org/10.3390/su13042340 - 22 Feb 2021
Cited by 24 | Viewed by 5777
Abstract
This article revisits social sustainability of compact urban neighbourhoods based on first-hand evidence from four case studies in London and Berlin. It suggests a working definition for socially sustainable neighbourhoods, develops a tripartite integrative evaluation framework for measuring social sustainability of urban neighbourhoods, [...] Read more.
This article revisits social sustainability of compact urban neighbourhoods based on first-hand evidence from four case studies in London and Berlin. It suggests a working definition for socially sustainable neighbourhoods, develops a tripartite integrative evaluation framework for measuring social sustainability of urban neighbourhoods, and applies it to four case studies in London and Berlin. Findings of this research are in line with some dominant arguments made in favour of social sustainability of compact urban form, but challenges some others. Research findings suggest that compact urban form is not an urban orthodoxy, but has multiple and contrasting social meanings and perceptions in different contexts and places. Full article
(This article belongs to the Collection Social Sustainability and New Urban Residential Spaces)
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23 pages, 7866 KiB  
Article
Global Analysis of Durable Policies for Free-Flowing River Protections
by Denielle Perry, Ian Harrison, Stephannie Fernandes, Sarah Burnham and Alana Nichols
Sustainability 2021, 13(4), 2347; https://doi.org/10.3390/su13042347 - 22 Feb 2021
Cited by 27 | Viewed by 8538
Abstract
Freshwater ecosystems are poorly represented in global networks of protected areas. This situation underscores an urgent need for the creation, application, and expansion of durable (long-term and enforceable) protection mechanisms for free-flowing rivers that go beyond conventional protected area planning. To address this [...] Read more.
Freshwater ecosystems are poorly represented in global networks of protected areas. This situation underscores an urgent need for the creation, application, and expansion of durable (long-term and enforceable) protection mechanisms for free-flowing rivers that go beyond conventional protected area planning. To address this need, we must first understand where and what types of protections exist that explicitly maintain the free-flowing integrity of rivers, as well as the efficacy of such policy types. Through policy analysis and an in-depth literature review, our study identifies three main policy mechanisms used for such protections: (1) River Conservation Systems; (2) Executive Decrees and Laws; and (3) Rights of Rivers. We found that globally only eight counties have national river conservation systems while seven countries have used executive decrees and similar policies to halt dam construction, and Rights of Rivers movements are quickly growing in importance, relative to other protection types. Despite the current extent of protection policies being insufficient to tackle the freshwater and biodiversity crises facing the world’s rivers, they do provide useful frameworks to guide the creation and expansion of protections. Ultimately, as countries act on global calls for protections, policy mechanisms must be tailored to their individual social and ecological geographies. Full article
(This article belongs to the Special Issue Durable Protections for Free-Flowing Rivers)
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25 pages, 4041 KiB  
Article
Assessment of Mechanical Properties and Structural Morphology of Alkali-Activated Mortars with Industrial Waste Materials
by Iman Faridmehr, Chiara Bedon, Ghasan Fahim Huseien, Mehdi Nikoo and Mohammad Hajmohammadian Baghban
Sustainability 2021, 13(4), 2062; https://doi.org/10.3390/su13042062 - 14 Feb 2021
Cited by 22 | Viewed by 3756
Abstract
Alkali-activated products composed of industrial waste materials have shown promising environmentally friendly features with appropriate strength and durability. This study explores the mechanical properties and structural morphology of ternary blended alkali-activated mortars composed of industrial waste materials, including fly ash (FA), palm oil [...] Read more.
Alkali-activated products composed of industrial waste materials have shown promising environmentally friendly features with appropriate strength and durability. This study explores the mechanical properties and structural morphology of ternary blended alkali-activated mortars composed of industrial waste materials, including fly ash (FA), palm oil fly ash (POFA), waste ceramic powder (WCP), and granulated blast-furnace slag (GBFS). The effect on the mechanical properties of the Al2O3, SiO2, and CaO content of each binder is investigated in 42 engineered alkali-activated mixes (AAMs). The AAMs structural morphology is first explored with the aid of X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy measurements. Furthermore, three different algorithms are used to predict the AAMs mechanical properties. Both an optimized artificial neural network (ANN) combined with a metaheuristic Krill Herd algorithm (KHA-ANN) and an ANN-combined genetic algorithm (GA-ANN) are developed and compared with a multiple linear regression (MLR) model. The structural morphology tests confirm that the high GBFS volume in AAMs results in a high volume of hydration products and significantly improves the final mechanical properties. However, increasing POFA and WCP percentage in AAMs manifests in the rise of unreacted silicate and reduces C-S-H products that negatively affect the observed mechanical properties. Meanwhile, the mechanical features in AAMs with high-volume FA are significantly dependent on the GBFS percentage in the binder mass. It is also shown that the proposed KHA-ANN model offers satisfactory results of mechanical property predictions for AAMs, with higher accuracy than the GA-ANN or MLR methods. The final weight and bias values given by the model suggest that the KHA-ANN method can be efficiently used to design AAMs with targeted mechanical features and desired amounts of waste consumption. Full article
(This article belongs to the Special Issue Sustainable Structural Design for High-Performance Buildings and Infrastructures)
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11 pages, 1680 KiB  
Review
Up-To-Date Challenges for the Conservation, Rehabilitation and Energy Retrofitting of Higher Education Cultural Heritage Buildings
by Luisa Dias Pereira, Vanessa Tavares and Nelson Soares
Sustainability 2021, 13(4), 2061; https://doi.org/10.3390/su13042061 - 14 Feb 2021
Cited by 42 | Viewed by 9002
Abstract
In higher-education world heritage sites, the conservation and energy retrofitting of heritage buildings (HBs) is an important vector for their development, competitiveness and welfare. To guarantee their ongoing use, these buildings must be adapted to face current and emerging societal challenges: (i) the [...] Read more.
In higher-education world heritage sites, the conservation and energy retrofitting of heritage buildings (HBs) is an important vector for their development, competitiveness and welfare. To guarantee their ongoing use, these buildings must be adapted to face current and emerging societal challenges: (i) the conservation of cultural heritage and the maintenance of their original characteristics and identity; (ii) the transformation of heritage sites into tourist centers that energize the local economy, generating revenue and jobs; (iii) the adaptation of the buildings to new uses and functions that demand energy retrofitting strategies to satisfy today’s standards of thermal comfort, indoor environmental quality (IEQ) and energy efficiency; (iv) tackling impacts of climate change, particularly global warming and extreme weather events; and finally, (v) the implementation of strategies to mitigate the impact of a growing number of tourists. The combined implications of these challenges require a comprehensive approach with interrelated measures strongly reliant on the use of technology and innovation. This work aims to discuss how higher-education cultural HBs can be rethought to serve these expectations. Moreover, a multidisciplinary intervention framework is provided to discuss how HBs can respond to the challenges and risks of rehabilitation, energy retrofitting, climate change and increasing tourism. Full article
(This article belongs to the Special Issue Thermal Behavior and Energy Efficiency of Buildings)
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23 pages, 20806 KiB  
Article
LCA and Exergo-Environmental Evaluation of a Combined Heat and Power Double-Flash Geothermal Power Plant
by Vitantonio Colucci, Giampaolo Manfrida, Barbara Mendecka, Lorenzo Talluri and Claudio Zuffi
Sustainability 2021, 13(4), 1935; https://doi.org/10.3390/su13041935 - 11 Feb 2021
Cited by 23 | Viewed by 4744
Abstract
This study deals with the life cycle assessment (LCA) and an exergo-environmental analysis (EEvA) of the geothermal Power Plant of Hellisheiði (Iceland), a combined heat and power double flash plant, with an installed power of 303.3 MW for electricity and 133 MW for [...] Read more.
This study deals with the life cycle assessment (LCA) and an exergo-environmental analysis (EEvA) of the geothermal Power Plant of Hellisheiði (Iceland), a combined heat and power double flash plant, with an installed power of 303.3 MW for electricity and 133 MW for hot water. LCA approach is used to evaluate and analyse the environmental performance at the power plant global level. A more in-depth study is developed, at the power plant components level, through EEvA. The analysis employs existing published data with a realignment of the inventory to the latest data resource and compares the life cycle impacts of three methods (ILCD 2011 Midpoint, ReCiPe 2016 Midpoint-Endpoint, and CML-IA Baseline) for two different scenarios. In scenario 1, any emission abatement system is considered. In scenario 2, re-injection of CO2 and H2S is accounted for. The analysis identifies some major hot spots for the environmental power plant impacts, like acidification, particulate matter formation, ecosystem, and human toxicity, mainly caused by some specific sources. Finally, an exergo-environmental analysis allows indicating the wells as significant contributors of the environmental impact rate associated with the construction, Operation & Maintenance, and end of life stages and the HP condenser as the component with the highest environmental cost rate. Full article
(This article belongs to the Special Issue Sustainability of Geothermal Energy Conversion—Life Cycle Analysis)
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24 pages, 7780 KiB  
Article
Innovative Renewable Technology Integration for Nearly Zero-Energy Buildings within the Re-COGNITION Project
by Giulia Mancò, Elisa Guelpa, Alessandro Colangelo, Alessandro Virtuani, Tommaso Morbiato and Vittorio Verda
Sustainability 2021, 13(4), 1938; https://doi.org/10.3390/su13041938 - 11 Feb 2021
Cited by 18 | Viewed by 4164
Abstract
With the 2010/31/EU directive, all new buildings shall be nearly zero-energy buildings (nZEB) from 2020 onward, with the aim of strongly reducing the energy consumption related to the building sector. To achieve this goal, it is not sufficient to focus on the design [...] Read more.
With the 2010/31/EU directive, all new buildings shall be nearly zero-energy buildings (nZEB) from 2020 onward, with the aim of strongly reducing the energy consumption related to the building sector. To achieve this goal, it is not sufficient to focus on the design of the building envelope; smart and efficient energy management is necessary. Moreover, to ensure the adoption of RES systems in the built environment, innovative technologies need to be further developed in order to increase their cost-effectiveness, energy efficiency and integration capability. This paper proposes a synthesis, design and operation optimization of an integrated multi-energy system composed of traditional and innovative renewable technologies, developed within the European project Re-COGNITION. A biogas-based micro cogeneration unit, lightweight glass-free photovoltaic modules, a passive variable geometry small wind turbine optimized for an urban environment and latent heat thermal storage based on phase change materials are some of the technologies developed within the Re-COGNITION project. The optimization problem is solved to contemporarily evaluate (a) the optimal design and (b) the optimal operations of the set of technologies considering both investment and operating costs, using mixed integer non-linear programming. The optimization is applied to the four pilots that are developed during the project, in various European cities (Turin (Italy), Corby (United Kingdom), Thessaloniki (Greece), Cluj-Napoca (Romania). Simulation results show that the development and optimal exploitation of new technologies through optimization strategies provide significant benefits in terms of cost (between 11% and 42%) and emissions (between 10% and 25%), managing building import/export energy and charge/discharge storage cycles. Full article
(This article belongs to the Special Issue Thermal Energy Storage, District Heating and Optimization in a Multi Energy System Context)
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18 pages, 4052 KiB  
Article
Alkaline Fractionation and Subsequent Production of Nano-Structured Silica and Cellulose Nano-Fibrils for the Comprehensive Utilization of Rice Husk
by Hyun Jin Jung, Hyun Kwak, Jinyoung Chun and Kyeong Keun Oh
Sustainability 2021, 13(4), 1951; https://doi.org/10.3390/su13041951 - 11 Feb 2021
Cited by 10 | Viewed by 2992
Abstract
The parameters of the alkaline fractionation process were investigated and optimized using a statistical analysis method to simultaneously remove hemicellulose and ash from rice husk (RH) concomitantly. After the alkaline fractionation process, the residual solid contained high cellulose, and the recovery yield of [...] Read more.
The parameters of the alkaline fractionation process were investigated and optimized using a statistical analysis method to simultaneously remove hemicellulose and ash from rice husk (RH) concomitantly. After the alkaline fractionation process, the residual solid contained high cellulose, and the recovery yield of hemicellulose was enhanced in the fractionated liquid hydrolyzate. The hemicellulosic sugar recovery yield (71.6%), de-ashing yield (>99%), and lignin removal (>80%) were obtained at the reaction conditions of 150 °C of temperature, 40 min of reaction time, and 6% (w/v) of NaOH concentration. Subsequently, nano-structured silica was synthesized using black liquor obtained as a by-product of this fractionation process. For the production of nano-structured silica, it was observed that the pH of a black liquor and the heat treatment temperature significantly influenced the textural properties of silica product. In addition, the two-stage bleaching of solid residue followed by colloid milling for the production of high value-added CNF with was attempted. As a result, in addition to 119 g of fermentable sugar, 143 g of high-purity (>98%) silica with a surface area of 328 m2g−1 and 273.1 g of high-functional CNF with cellulose content of 80.1% were simultaneously obtained from 1000 g of RH. Full article
(This article belongs to the Special Issue Valorization of Residues from Energy Conversion of Biomass for Advanced and Sustainable Material Applications)
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17 pages, 1546 KiB  
Review
Water-Energy-Food Nexus: Critical Review, Practical Applications, and Prospects for Future Research
by Aries Purwanto, Janez Sušnik, Franciscus X. Suryadi and Charlotte de Fraiture
Sustainability 2021, 13(4), 1919; https://doi.org/10.3390/su13041919 - 10 Feb 2021
Cited by 76 | Viewed by 12961
Abstract
This paper presents knowledge gaps and critiques on the water–energy–food (WEF) nexus that have emerged since the concept of the WEF nexus was proposed by the World Economic Forum and the Bonn 2011 Conference. Furthermore, this study analyses current innovations on the WEF [...] Read more.
This paper presents knowledge gaps and critiques on the water–energy–food (WEF) nexus that have emerged since the concept of the WEF nexus was proposed by the World Economic Forum and the Bonn 2011 Conference. Furthermore, this study analyses current innovations on the WEF nexus concept, applications, and impacts during the period of 2012–2020. This begins by reviewing ten WEF nexus frameworks developed by international organizations and researchers. On this basis, several gaps and omissions in nexus frameworks are obvious in almost all developed frameworks. Studies that start to address some of these gaps are analysed, but they are relatively few and do not address all gaps. Several proposed improvements to nexus frameworks are identified to narrow the gaps and put the concept into practical implementation in WEF resources management and governance. Four principles and the perspective of “from local to global” for future WEF nexus framework development and analysis are suggested to ensure that the security of water, energy, and food resources can be achieved sustainably in local communities. This will improve the impact of national and global ambitions on WEF security. Full article
(This article belongs to the Section Energy Sustainability)
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30 pages, 4305 KiB  
Article
Optimized Physical Properties of Electrochromic Smart Windows to Reduce Cooling and Heating Loads of Office Buildings
by Jae-Hyang Kim, Jongin Hong and Seung-Hoon Han
Sustainability 2021, 13(4), 1815; https://doi.org/10.3390/su13041815 - 8 Feb 2021
Cited by 14 | Viewed by 3535
Abstract
The concept of smart windows that can change the properties of windows and doors in response to external stimuli has recently been introduced. Smart windows provide superior energy savings and control of indoor environments. This concept can advance sustainable architecture, and it will [...] Read more.
The concept of smart windows that can change the properties of windows and doors in response to external stimuli has recently been introduced. Smart windows provide superior energy savings and control of indoor environments. This concept can advance sustainable architecture, and it will make it possible to connect with the fourth industry, which has developed recently. However, unlike the relevant hardware, is advancing rapidly, research on methods of adjusting smart windows is slow. Therefore, in this study, an analysis of energy use over time was conducted on electrochromic windows, one of the main types of smart windows. Through this analysis, the optimal properties of electrochromic smart windows were identified, and an operation schedule was created. In addition, energy saving rates were derived through a comparison with existing architectural windows. Full article
(This article belongs to the Special Issue Sustainable Conversion of Renewable Energy Sources)
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15 pages, 4175 KiB  
Article
Quantitative Assessment of Energy Supply Security: Korea Case Study
by Herie Park and Sungwoo Bae
Sustainability 2021, 13(4), 1854; https://doi.org/10.3390/su13041854 - 8 Feb 2021
Cited by 14 | Viewed by 4836
Abstract
Ensuring energy supply security has become one of the most important purposes for many countries. To make the strategies for ensuring the energy supply security of a country, it is essential to quantitatively assess the security. This paper aims to present a methodology [...] Read more.
Ensuring energy supply security has become one of the most important purposes for many countries. To make the strategies for ensuring the energy supply security of a country, it is essential to quantitatively assess the security. This paper aims to present a methodology to evaluate the energy supply security of a country by using different indices of energy dependence and energy diversity, which have been raised as two main paradigms of energy supply security. This study also proposes two indices reflecting the correlation between a country’s energy diversity and energy import dependence to evaluate its energy supply security based on easily accessible data. The presented methodology and indices were applied to the evaluation of the primary energy supply security of Korea from 1991 to 2018. The results show that a country highly dependent on energy imports is not evaluated as secure enough in terms of energy supply even if it obtains higher energy diversity. This finding supports the importance of the correlation of energy dependence and energy diversity of a country to ensure its energy supply security. This approach could be further adapted to other countries and help them to make their energy policy and strategies. Full article
(This article belongs to the Collection Secure and Sustainable Energy System)
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18 pages, 2080 KiB  
Article
Application of Multi-Actor Multi-Criteria Analysis for Transition Management in Energy Communities
by Maria Luisa Lode, Geert te Boveldt, Cathy Macharis and Thierry Coosemans
Sustainability 2021, 13(4), 1783; https://doi.org/10.3390/su13041783 - 7 Feb 2021
Cited by 18 | Viewed by 5631
Abstract
Energy communities (ECs) play a role in the transition towards a low-carbon economy by 2050 and receive increasing attention from stakeholders within the energy sector. To foster ECs, transition management (TM) is a promising managerial approach to steer and guide the transition towards [...] Read more.
Energy communities (ECs) play a role in the transition towards a low-carbon economy by 2050 and receive increasing attention from stakeholders within the energy sector. To foster ECs, transition management (TM) is a promising managerial approach to steer and guide the transition towards more sustainable practices. However, TM lacks a consistent methodology that addresses the criticism of the current application. To investigate what a structured and replicable TM approach for ECs can look like, this paper applies the multi-actor multi-criteria analysis (MAMCA), a participative multi-criteria decision method, to a case study EC in the Netherlands involving various stakeholders. The impact of the application on power relations, the political sphere, sustainability conceptualization, guidance of transitions, and representation was analyzed. MAMCA was found useful for multi-stakeholder settings seen in potential ECs, offering a unifying methodology for the practical application of TM. In the EC setting, the added value of MAMCA within TM lies more in the social representation, insight into stakeholder viewpoints, and communication rather than in final decision-making. Full article
(This article belongs to the Special Issue Energy Communities in the Changing Energy Landscape)
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