A significant challenge for the DSO (Distribution System Operator) will be to choose the optimum strategy for flexibility service in the LV area with high RES (renewable energy sources) penetration. To this end, a representative LV grid operated in Poland was selected for analysis. Three research scenarios with RES generation were presented in the range of 1−8 kW for the power factor from 0.9 to 1. The grid PV capacity was determined for four load profiles. Based on this factor, optimum RES volume management service types were determined. Under the flexibility service, the proposed power conversion services and active RES operations for DSO were proposed. The research was conducted using the Matlab and PowerWorld Simulator environment. Optimum active power values were obtained for the RES generation function for single and dual operation systems of the power conversion system. In future, the knowledge in the field of grid capacity will enable the DSO to increase the operating efficienc... [more]

This study investigated the evaporative heat transfer coefficient and pressure drop characteristics of R-1234yf in a horizontal tube with an inner diameter of 6.95 mm under various experimental conditions. The heat transfer coefficient increased with an increase in quality but showed a sharp decrease in the high-quality area. In addition, the heat transfer coefficient increased as the mass flux, heat flux, and saturation temperature increased. Although R-1234yf and R-134a presented similar heat transfer coefficients, that of R-134a was higher. The pressure drop increased with an increase in the quality and mass flux but decreased with an increase in the saturation temperature. The pressure drop of R-134a was larger than that of R-1234yf. In light of the flow pattern diagram by Taitel and Dukler, most of the experiments were included in the annular flow region, and some regions showed intermittent and stratified corrugated flow regions. Kandlikar’s heat transfer coefficient correlation... [more]

Power Internet of Things (IoT) is the application of IoT technology in the field of power grid, which can better control all kinds of power equipment, power personnel and operating environment. However, access to mass terminals brings higher requirements for terminal authentication and key management for the power IoT. And the traditional public key infrastructure (PKI) and identity-based public key cryptography (IB-PKC) exist the problems of certificate management and key escrow. Therefore, the paper proposes a novel authenticated key agreement scheme based on the certificateless public key cryptography (CL-PKC) mechanism. In addition, the proposed scheme is proven with the improved extended Canetti-Krawczyk (eCK) security model. Finally, the implementation of the authenticated key agreement protocol is given based on the actual application requirement of the power IoT, and the analysis and comparison of the simulation demonstrates that the proposed scheme has higher efficiency and wo... [more]

Calculation and measurement of the overhead power lines electrical parameters is common practice in today’s electrical engineering industry; however, there is very little data to actually compare these two approaches because measured data in such detail are mostly unavailable for academic purposes. Based on the very detailed model of an overhead power line in MATLAB Simulink environment and conducted experimental measurement, this article specifically covers the exact evaluation of the impedance of the investigated overhead power line. Differences between calculation and experimental measurement are shown and discussed accordingly, where, surprisingly, the biggest deviation was observed in the positive resistance parameter. The connection between different measurement techniques (multiple single-phase and three-phase methods), as well as the power line asymmetry reflection in the impedance matrix is explained as well as compared to expected values from the computations. The complete ma... [more]

Increasing economic and population growth has put immense pressure on energy, water and land resources to satisfy national and supra-national demand. Through trade, a large proportion of such a demand is fulfilled. With trade as one of its key priorities, the China Belt and Road Initiative is a long-term transcontinental investment program. The initiative gained significant attention due to greater opportunities for economic development, large population and different levels of resource availability. The nexus approach has appeared as a new viewpoint in discussions on balancing the competing sectoral demands. However, following years of work, constraints exist in the scope and focus of studies. The newly developed multi-regional input−output (MRIO) models covering the world’s economy and its use of resources permit a comprehensive analysis of resource usage by production and consumption at different levels, and bring more knowledge about resource nexus problems. Using the MRIO model, t... [more]

The advancements in sensor and communication technologies drive the rapid developments in the applications of occupancy and indoor environmental monitoring in buildings. Currently, the installation standards for sensors are scarce and the recommendations for sensor positionings are very general. However, inadequate sensor positioning might diminish the reliability of sensor data, which could have serious impacts on the intended applications such as the performance of demand-controlled HVAC systems and their energy use. Thus, there is a need to understand how sensor positioning may affect the sensor data, specifically when using multi-sensor devices in which several sensors are being bundled together. This study is based on the data collected from 18 multi-sensor devices installed in three single-occupant offices (six sensors in each office). Each multi-sensor device included sensors to measure passive infrared (PIR) radiation, temperature, CO2, humidity, and illuminance. The results sh... [more]

Sewage sludge from wastewater treatment plants is commonly used as a soil amendment on agricultural land. Unfortunately, more and more research indicates that large amounts of microplastic (MP) are re-introduced to soil with sludge. This study aims to present the impact MP has on soil ecosystems, global trends in agricultural sludge management resulting from a high concentration of micropollutants in sludge, and finally propose a high-level strategy for sustainable sludge management. This strategy is mostly dedicated to the European Union and involves multiple stakeholders and the links between each of them to achieve appropriate sludge management to avoid soil pollution with MP. Governance, Technology, Consumer Acceptance, and Economy and Commercial Viability is explored in depth. To the author’s knowledge, this is the first paper to discuss these topics in the context of a changing agricultural scene and identifies ways of which sewage sludge can limit MP pollution whilst still fitti... [more]

The integration of renewables into power systems is a key transformation for mitigating climate change and reducing fossil-fuel dependence. Among the different resources, wind participation has become crucial in recent decades—both onshore and offshore wind power plants. However, assuming the useful life of the wind turbines at approximately 20 years, different solutions should be discussed to overcome the turbine’s aging problem. In the coming years, some countries within the wind sector will face the decision of partially or totally repowering or dismantling their turbines. This paper reviews different repowering strategies and contributions from a multifactorial perspective. A set of categories is defined by the authors and those multifactorial parameters are then classified according to such categories: technical, economic, environmental, social, and political. From each category, the most relevant factors to be considered for repowering decision-making purposes are identified and... [more]

Poland has had a total of 70 mines, but now more than half of them is out of operation. This mining closure raises with respect to the environment and unemployment. Innovative technology is needed to overcome the problems that arise and could simultaneously make use of abandoned mine infrastructure. The increased electricity generation coming from renewable energy, which produces fluctuating and intermittent energy for the electric power system, causes frequency problems such that energy storage technologies are needed. Abandoned mines can be used for the implementation of energy storage plants. This paper explores the possibility of using abandoned mines in Poland for electrical energy storage. Closed mines can be used to store clean and flexible energy. This idea has the potential to support sustainable economic development within the community following mine closure in Poland.

Corporate social responsibility (CSR) assumes that companies should justify their existence with services for various stakeholders and not with profit alone. There is a strong emphasis on the implications of CSR for managing human resources in hotels and other accommodation services, supporting local communities, and promoting environmental sustainability. This article aims to present the adjustment of business entities providing accommodation services in Poland to the CSR principles. Two aspects were examined: the environmental aspect, i.e., waste segregation and the use of economic energy receivers, while the social aspect included engaging employees, as well as investing in improving their qualifications towards pro-ecological awareness. The study was conducted on a sample of 207 owners and managers of economic entities in the accommodation sector in Poland. The Statistica software was used to analyze the obtained results, including Chi2 statistics and correspondence analysis. Based... [more]

An urgent demand for recycling spent lithium-ion batteries (LIBs) is expected in the forthcoming years due to the rapid growth of electrical vehicles (EV). To address these issues, various technologies such as the pyrometallurgical and hydrometallurgical method, as well as the newly developed in-situ roasting reduction (in-situ RR) method were proposed in recent studies. This article firstly provides a brief review on these emerging approaches. Based on the overview, a life cycle impact of these methods for recovering major component from one functional unit (FU) of 1 t spent EV LIBs was estimated. Our results showed that in-situ RR exhibited the lowest energy consumption and greenhouse gas (GHG) emissions of 4833 MJ FU−1 and 1525 kg CO2-eq FU−1, respectively, which only accounts for ~23% and ~64% of those for the hydrometallurgical method with citric acid leaching. The H2O2 production in the regeneration phase mainly contributed the overall impact for in-situ RR. The transportation di... [more]

This study investigated the contributions of human capital and physical capital to economies at different stages by measuring the economic development with the traditional GDP and green GDP. The traditional GDP stood for the quantity of economic growth, and the green GDP, taking both the energy consumption and environmental pollution into account, was employed to represent the sustainability of economic development. We used a panel data of 143 countries and regions during the period from 1990 to 2014, and results showed that the elasticities of output with respect to human capital were greater compared to physical capital, while green GDP was significantly more sensitive to changes in human capital than the traditional GDP. In particular, considering the unbalanced distribution of economic growth among countries and regions, we employed the quantile regression model to explore the heterogeneous roles of physical and human capital in different stages of economic development, which evide... [more]

Increasing participation in demand response within the industrial sector may be crucial to growing the levels of available flexible capacity required to reliably control national electricity grids as renewable generation increases to satisfy emission targets. This research aims to assist the uptake of demand response in the industrial sector by investigating risk to indoor thermal environments on industrial sites offering air handling unit capacity for demand response. This evaluation uses a systematic model-based approach, calibrated and validated with empirical data from a relevant case study industrial building to assess risk through a number of scenarios. The conditions investigated cover several relevant grid response times and durations, and national and international extreme external ambient temperatures in the past, present and future under a variety of temperature limits. The study demonstrated that there is very low risk to the case study site participating in demand response... [more]

Experiments were carried out to investigate the heat transfer and pollutants emission characteristics of a slot LPG premixed flame array impinging normally onto a flat plate. The effects of jet-to-jet spacing (S/de), nozzle-to-plate distance (H/de), and jet Reynolds number (Re) on the heat flux and emission index of CO, CO2, and NOx/NO2 were examined. In addition, the thermal and emission characteristics between slot jets and circular jets were compared under identical experimental conditions. The results show that the more uniform heat flux distribution and higher total heat flux can be obtained at moderate jet-to-jet spacing, large jet-to-plate distance, and higher Reynolds number. EICO emissions can be influenced by the combined effects of jet-to-jet spacing, jet-to-plate distance, and higher Reynolds number. For the sake of the better combustion efficiency and lower EICO emission, the moderate jet-to-jet spacing (S/de = 2.5), larger jet-to-plate distance (H/de = 4), and relatively... [more]

This study provides an in-depth assessment of the environmental performance of five public schools in the transition towards a low-carbon economy and a more sustainable model of society. Life cycle assessment (LCA) methodology is used to conduct the study. The school system includes several activities and processes clustered in three subsystems: management of the school building, training and learning activities (T&L) and mobility and transport (M&T). A detailed primary data inventory of energy and resources consumption was collected in five schools located in Spain and Portugal. Findings on climate change (CC), water depletion (WD), particular matter (PM), acidification (Ac), and human health (HH), as well as associated external cost (EC), are reported per student in one school year as reference unit, allowing the schools’ individual performance comparison and identify the potential improvements. Considering the sample of schools, findings reveal that peculiarities of the schools, suc... [more]

Although eco-friendly (pro-environmental) behaviour in tourism has attracted interest among practitioners and scholars, little is known about the influence of these attitudes on the choice of eco-friendly destinations, especially in the context of emerging tourist markets such as India. Thus, this article aims to verify a model of the relationships between attitudes towards the environment and eco-friendly tourism, social and personal norms regarding environmentally responsible behaviour, perceived behavioural control, behavioural intentions regarding eco-friendly destinations and the willingness to pay for such trips using the theory of planned behaviour. The study used an online survey conducted with 598 Indians. The relationships between the variables were analysed using PLS-PM. The most important results indicated that (1) there are significant relationships between the attitude towards the environment, the attitude towards an eco-friendly destination, social and personal norms and... [more]

The present work involves a new and novel upgrading design to the classical solar chimney power plant (SCPP) structure. The SCPP design was modified by adding a co-centric secondary external chimney to the SCPP structure to enhance energy production. In the new improved design, named the solar double-chimney power plant (SDCPP), the internal chimney, operates like a traditional SCPP to produce electricity during the daytime whereas the secondary external chimney operates as 10 cooling towers (CT) in a series. Each CT is equipped with a turbine and water sprinklers for further energy production. The new design offers the operation of the SCPP during the day and the continuous operation of the CT (day-and-night). A mathematical model that includes the energy and mass balance equations of the system was built using MATLAB. The SDCPP system produced up to 993 MWh of electrical energy, which is 2.6 times higher than the traditional SCPP (377 MWh). The new design configuration achieved a per... [more]

Epidemiological research has shown that there is a positive correlation between the incidence of disease and mortality in humans and the mass concentration of particulate matter. An average 1 g of suspended dust emitted in a room results in the same exposure as 1 kg emitted to the outside air. In this study, the authors described the state of knowledge on dust pollution inside and outside buildings (I/O ratios), and methods of testing the PM infiltration process parameters. According to the law of indoor−outdoor particle mass balance and the physical basis of aerosol penetration theory, a relatively simple but new method for estimating the penetration factor P was tested. On the basis of the curve of dynamic changes of internal dust concentration in the process of particle concentration decay and next of the followed curve of dynamic rebound of particle concentration, authors measured penetration factor of ambient PM2.5 through building envelope. Authors modification of the method is t... [more]

Islands are widely recognised as ideal pilot sites that can spearhead the transition to clean energy and development towards a sustainable and healthy society. One of the assumptions underpinning this notion is that island communities are more ready to engage with smart grids (SGs) than people on the mainland. This is believed to be due to the high costs of energy on islands and the idea that the sense of community and collective action is stronger on islands than on the mainland. This paper presents findings from a survey conducted to assess people’s perception of, and readiness to engage with, SG and demand response (DR) in the communities of three islands taking part in a H2020 project called REACT. The main objective of the survey, conducted in 2020, was to inform the recruitment of participants in the project, which is piloting different technologies required for SGs and DR with communities on the three islands. The results show that many island residents are motivated to take par... [more]

Air pollution, which causes over seven million deaths per year, is the most significant and specifically related to health impacts. Nearly 90% of the urban population worldwide is exposed to pollution not meeting the World Health Organization guidelines for air quality. Many atmospheric carbon oxides, nitrogen oxides, and particulate matter emitting sources, such as inefficient energy and polluting transportation, directly impact health. Natural gas maritime transport from various parts of the world (carbon supplied to consuming areas) has become more critical. Natural gas liquefaction offers a cleaner and more efficient transportation option and also increases its storage capacity. It is expected that natural gas will reduce the human health impact compared with other traditional fuels consumed. This research establishes a life cycle assessment model of air emission and social human health impact related to LNG maritime transport to investigate the impact of each type of fuel used for... [more]

The paper presents a new, unconventional energy harvesting (EH) method for supplying low-power devices on electrified railway lines that utilises stray currents and the non-zero potential of the rails to the ground. The EH device gathers the energy and stores it in batteries. It could even work in extremely unfavourable weather conditions and could be easily placed in almost any location. The presented real-life data show that the average available power is less than 250 mW and the average useful power is about 100 mW. This is enough to supply ultra-low power microcontrollers, which only occasionally use energy-consuming modules to perform measurements or communicate. The disadvantage of the EH method is the introduction of resistance between the rail and the earth, which increases stray currents and could increase the electrochemical corrosion of the rail. To reduce the impact of this resistance, a method for balancing the flowing charge is proposed. After balancing, the average of th... [more]

Failure behavior of pillars in deep mines is affected by various cyclic loads that cause initial pre-damage. Pillars will be further damaged and developed in the long-term compressive stress until they are destroyed. To reveal the strength characteristics and crack damage fracture laws after rock pre-damage, uniaxial compression tests were carried out on granite specimens damaged by cyclic loading using the digital speckle correlation method. The experimental results indicate that the mechanical properties of pre-damaged specimens show large damage differences for different cycles. The damage variable of the pre-damaged specimens increases with the increase of cycle number and confining pressure. The damage of specimens is primarily due to the strength weakening effect caused by cycle numbers, and the confining pressure restriction effect is not obvious. The evolution laws of uniaxial compression damage propagation in the pre-damaged specimens show differences and obvious localization... [more]

Determining the spatial position of wind turbines is the initial and most important phase in the development of a wind farm project. In this sensitive phase, all potential problems that may arise in the later stages of project development should be prevented by means of spatial and urban planning instruments. This makes it possible to achieve maximum use of the potential of wind in a particular space and, thus, fulfil the technical and economic requirements of the project while respecting the goals of environmental protection in that same area, through preventive protection. Therefore, it is essential, even at the earliest planning and development stage of a wind farm project, for the requirements that are important for optimal spatial solutions to be balanced. In this process, strategic environmental assessment (SEA) is a support to the planning process and an invaluable instrument for finding optimal spatial solutions for the possible key spatial impacts of wind power with regard to... [more]

The most recent research confirms that airborne transmission may be the dominant mode of SARS-CoV-2 virus spread in the interior spaces of buildings. Consequently, based on some prescriptions that implemented natural ventilation during face-to-face lessons in a university centre, an experimental characterization of several complementary options aimed at reinforcing the prevention and safety of the occupants was carried out. The action protocol adopted was based on the combination of mandatory natural ventilation, a maximum contribution of outdoor air supply in the air conditioning system, and the use of filtering devices located inside the classroom. All the strategies were incorporated concomitantly with necessary compliance with the basic conditions of social distance, occupation, use of masks and guidelines for use and cleaning within educational buildings. The suitability of this protocol was further evaluated throughout the teaching day with students and teachers by measuring the... [more]

According to one definition, Smart City is an administrative unit that uses data and digital technology to improve the decision-making processes and well-being of its inhabitants. Smart Cities use modern, intelligent technologies to forecast future changes, optimize city functions, gain a better understanding of current conditions, and deliver solutions. To make the city smart, multiple connected sensors, smartphones and other IoT devices are needed. As part of the research conducted at the Technical University in Vienna, six key dimensions (categories) of smart cities have been identified and characterized: Smart Economy, Smart Mobility, Smart Environment, Smart People, Smart Living, and Smart Governance. The aim of the paper is to present the concept of the smart cities, the implemented innovative solutions and the issue of electricity saving in Smart Cities. The theoretical considerations were expanded of the presentation of selected smart city projects in Polish cities. The conside... [more]