Soot is an important component for heat transfer in combustion processes. However, it is also a harmful pollutant for humans, and strict emissions legislation motivates research on how to control soot formation and release. The formation of soot is known to be triggered by high temperature and high pressure during combustion, and it is also strongly influenced by the local stoichiometry. The current study investigates how the formation of soot is affected by increasing the oxygen concentration in the oxidizer, since this affects both the temperature profile and partial pressures of reactants. The oxygen-to-fuel ratio is kept constant, i.e., the total flow rate of the oxidizer decreases with increasing oxygen concentration. Propane is combusted (80 kWth) while applying oxygen-enriched air, and in-flame measurements of the temperature and gas concentrations are performed and combined with available soot measurements. The results show that increasing the oxygen concentration in the oxidiz... [more]

The role of buildings in the context of addressing the consequences of climate change and the energy deficit is becoming increasingly important due to their share in the overall amount of green house gas (GHG) emissions and rapidly growing domestic energy consumption worldwide. Adherence to a sustainability agenda requires ever-increasing attention to all stages of a building′s life, as such approach allows for the consideration of environmental impacts of a building, from design, through construction stages, until the final phase of a building′s life—demolition. A life cycle assessment (LCA) is one of the most recognized and adopted models for the evaluation of the environmental performance of materials and processes. This paper aims to perform an LCA of four different types of residential buildings in Nur-Sultan, Kazakhstan. The assessment primarily considered embodied energy and GHG emissions as key assessment indicators. Findings suggest that the operational stage contributed to mo... [more]

To improve the adaptability of direct air-cooled power generating units to the variations of both meteorological condition and power load, a piping-main arrangement of air-cooled condensers was proposed. The heat and mass transfer models of the air-side were established for the air cooling system of 2 × 600 MW thermal power generating units. The coupled model for both flow resistance loss and condensate flow rate distributions of exhaust steam inside air-cooled condensers were developed based on the temperature fields through numerical simulation. Calculation results, including the condensate flow rate, back pressure, and coal consumption rate, were acquired under different ambient temperatures and wind velocities. The results show that the proposed piping-main arrangement can weaken the ambient wind impacts and reduce the backpressure significantly in summer by adjusting the number of air-cooled condenser cells in operation. The steam flow rate can be uniformed effectively by adjustin... [more]

In recent years, the energy performance of public buildings has attracted substantial attention due to the significant energy-saving potential. As a semi-open high-space building, the high-speed railway station is obviously different from other public buildings and even traditional stations in terms of energy consumption and internal environment. This paper investigates the current energy consumption situation and environmental quality of 15 high-speed railway passenger stations in China. Results show that the energy consumption of the high-speed railway station is between 117−470 kWh/(m2·a). The energy consumption of the station is related to the area and the passenger flow. The energy use of the station using district heating is higher than that of the station without district heating in the same region. The higher glazing ratio induces good natural lighting in the station, but the uniformity of the lighting in the station is not good. The acceptable temperature range of passengers i... [more]

This paper investigates the nucleate boiling process of dimethyl ether and selected hydrocarbons. The main goal of this study is to measure the heat transfer coefficients of RE170, R600a, and R601, and to compare them with R134a. The experiments were carried out for heat fluxes up to 70 kW/m2. Experimental results have shown a typical trend that the heat transfer coefficient of flammable refrigerants increases as the heat flux increases. Among the tested fluids, the highest values of heat transfer coefficient were obtained for RE170. Available correlations describing this coefficient showed a deviation of up to 93%, as compared to the data obtained. The new correlation was developed by regression analysis taking into account dimensionless variables affecting the boiling process.

Environmental impact assessment is a crucial aspect of biofuels production to ensure that the process generates emissions within the designated limits. In typical cellulosic biofuel production process, the pretreatment and downstream processing stages were reported to require a high amount of chemicals and energy, thus generating high emissions. Cellulosic butanol production while using low moisture anhydrous ammonia (LMAA) pretreatment was expected to have a low chemical, water, and energy footprint, especially when the process was combined with more efficient downstream processing technologies. In this study, the quantification of environmental impact potentials from cellulosic butanol production plants was conducted with modeled different pretreatment and product separation approaches. The results have shown that LMAA pretreatment possessed a potential for commercialization by having low energy requirements when compared to the other modeled pretreatments. With high safety measures... [more]

The effect of supercritical CO2 on the shaly caprocks is one of the critical issues to be considered in CO2 sequestration programs. Shale-scCO2 interactions can alter the seal integrity, leading to environmental problems and bringing into question the effectiveness of the program altogether. Several analytical studies were conducted on samples from Jurassic Eneabba Basal Shale and claystone rich facies of the Triassic Yalgorup Member (725−1417 m) in the Harvey CO2 sequestration site, Western Australia, to address the shale-scCO2 interactions and their effect on the petrophysical properties of the caprock. Shale samples saturated with NaCl brine were exposed to scCO2 under the reservoir condition (T = 60 °C, P = 2000 psi) for nine months and then tested to determine their altered mineralogical, petrophysical and geochemical properties. The experimental study examined changes to the mineralogical composition, capillary threshold pressure, and pore size distribution (PSD) of samples. The... [more]

This paper presents an environmental, economic and energy (3E) assessment of an energy retrofitting of the external walls of a flat of an average building with the most current characteristics used in Portugal. For this intervention, a cork-based (as recycled lightweight aggregate) TIRM (Thermal Insulating Rendering Mortar) was considered. The declared unit was 1 m2 of an external wall for a 50-year study period and the energy and economic costs and savings, as well as the environmental impacts, were analytically modelled and compared for two main alternatives: the reference wall without any intervention and the energetically rehabilitated solution with the application of TIRM. Walls with improved energy performance (with TIRM) show lower economic and environmental impacts: reductions from 6% to 32% in carbon emissions, non-renewable energy consumption and costs during the use stage, which depends on the thickness and relative place where TIRM layers are applied. A worse energy perform... [more]

Improving the energy efficiency of buildings is among the most urgent social development tasks due to the scale of energy consumption in this industry. At the same time, it is essential to meet high requirements for indoor environmental quality and thermal comfort. The issue of overheating is most often analysed in summer but it also occurs in transition seasons, when the cooling systems do not operate. The paper attempts to evaluate the effectiveness of external mobile shading elements on the microclimate of rooms with large glazed areas in the transition season. Passive solutions, such as shading elements, which limit the increase of indoor temperature, do not always allow the acquisition and maintenance of comfortable solutions for the duration of the season, as demonstrated by the authors. Temporary cooling of the rooms may be necessary to maintain comfortable conditions for the users, or other solutions should be devised to improve comfort (e.g., reduction of clothing insulation c... [more]

The aim of this study is to assess how the use of fossil and nuclear power in different renovation scenarios affects the environmental impacts of a multi-family dwelling in Sweden, and how changes in the electricity production with different energy carriers affect the environmental impact. In line with the Paris Agreement, the European Union has set an agenda to reduce greenhouse gas emissions by means of energy efficiency in buildings. It is estimated that by the year 2050, 80% of Europe’s population will be living in buildings that already exist. This means it is important for the European Union to renovate buildings to improve energy efficiency. In this study, eight renovation scenarios, using six different Northern European electricity mixes, were analyzed using the standard of the European Committee for Standardization for life cycle assessment of buildings. This study covers all life cycle steps from cradle to grave. The renovation scenarios include combinations of photovoltaics,... [more]

Increasing problems regarding pollution and climate change have long been demonstrated by scientific evidence. An important portion of carbon emissions are produced by the building sector. These emissions are directly related not only to the building’s energy consumption, but also other building attributes affecting the construction and operation of existing buildings: materials selection, waste management, transportation, water consumption, and others. To help reduce these emissions, several green building rating system (GBRSs) have appeared during the last years. This has made it difficult for stakeholders to identify which GBRSs could be more suitable to a specific project. The heterogeneity of the GRBS scenario requires the creation of a transparent and robust indicator framework that can be used in any country within the European Union (EU), which is a common EU framework of core sustainability indicators for office and residential buildings Level(s) with the goal to provide a sol... [more]

In electric vehicles with lithium-ion battery systems, the temperature of the battery cells has a great impact on performance, safety, and lifetime. Therefore, developing thermal models of lithium-ion batteries to predict and investigate the temperature development and its impact is crucial. Commonly, models are validated with experimental data to ensure correct model behaviour. However, influences of experimental setups or comprehensive validation concepts are often not considered, especially for the use case of prismatic cells in a battery electric vehicle. In this work, a 3D electro−thermal model is developed and experimentally validated to predict the cell’s temperature behaviour for a single prismatic cell under battery electric vehicle (BEV) boundary conditions. One focus is on the development of a single cell’s experimental setup and the investigation of the commonly neglected influences of an experimental setup on the cell’s thermal behaviour. Furthermore, a detailed validation... [more]

The quality and controllability of the building façade can significantly contribute to building indoor environmental quality (IEQ) as well as the building’s energy efficiency. Advanced technologies that support a façade’s dynamic response to climatic changes, such as electrochromic (dynamic) glazing, have emerged as smart systems for IEQ and environmental sustainability. This research summarizes a four-season study of office workers moving from a floor with conventional blinds to work environments equipped with smart dynamic glazing which changes tint in response to weather condition to control daylighting levels. Multiple occupant environmental satisfaction surveys were conducted over one year to investigate differences in environmental and psychological responses to office settings with manual, and often static, facades as compared to offices with dynamic glazing. This research confirms that dynamic glazing significantly affected occupants’ environmental satisfaction—enhancing indivi... [more]

The paper presents the results of research on the physicochemical properties of plant biomass consisting of four mint species, these being Mentha × piperita L. var. citrata Ehrh.—‘Bergamot’, Mentha × rotundifolia L., Mentha spicata L., and Mentha crispa L. The research conducted consisted of the technical analysis of biofuels—determining the heat of combustion and the calorific value of the material under study, and the content of ash, volatile compounds, and humidity. In addition, elemental analysis was carried out for the biomass under study by determining the content of carbon, hydrogen, nitrogen, and sulfur. The research demonstrated that Mentha × piperita L. var. citrata Ehrh.—‘Bergamot’ had the highest energy potential with a gross calorific value of 16.96 MJ·kg−1, and a net calorific value of 15.60 MJ·kg−1. Among the tested materials, Mentha × rotundifolia L. had the lowest content of ash at 7.23%, nitrogen at 0.23%, and sulfur at 0.03%, and at the same time had the highest cont... [more]

This study aims to propose a pose classification model using indoor occupant images. For developing the intelligent and automated model, a deep learning neural network was employed. Indoor posture images and joint coordinate data were collected and used to conduct the training and optimization of the model. The output of the trained model is the occupant pose of the sedentary activities in the indoor space. The performance of the developed model was evaluated for two different indoor environments: home and office. Using the metabolic rates corresponding to the classified poses, the model accuracy was compared with that of the conventional method, which considered the fixed activity. The result showed that the accuracy was improved by as much as 73.96% and 55.26% in home and office, respectively. Thus, the potential of the pose classification model was verified for providing a more comfortable and personalized thermal environment to the occupant.

During the extraction of hard coal in Polish conditions, methane is emitted, which is referred to as ‘mine gas’. As a result of the desorption of methane, a greenhouse gas is released from coal seams. In order to reduce atmospheric emissions, methane from coal seams is captured by a methane drainage system. On the other hand, methane, which has been separated into underground mining excavations, is discharged into the atmosphere with a stream of ventilation air. For many years, Polish hard coal mines have been capturing methane to ensure the safety of the crew and the continuity of mining operations. As a greenhouse gas, methane has a significant potential, as it is more effective at absorbing and re-emitting radiation than carbon dioxide. The increase in the amount of methane in the atmosphere is a significant factor influencing global warming, however, it is not as strong as the increase in carbon dioxide. Therefore, in Polish mines, the methane−air mixture captured in the methane dr... [more]

The competition and interlinkages between energy, water, and land resources are increasing globally and are exacerbated by climate change and a rapid increase in the world population. The nexus concept has emerged for a comprehensive understanding related to the management and efficiency of resource use. This paper assesses water−energy−land nexus (WELN) efficiency through integration of the principles of Life Cycle Assessment (LCA) and exergy analysis, using the Chilean energy sector (CES) as a study case. The cumulative exergy consumption (CExC) and cumulative degree of perfection (CDP) are used as indicators for WELN efficiency. The results show the production of 1 MWh of electricity required 17.3 GJex, with the energy component of WELN (fossil and renewable energy sources) being the main contributor (99%). Furthermore, the renewable energy technologies depicted higher CDP of the water−energy−land nexus due to lower CExC and higher technology efficiency concerning non-renewables. Th... [more]

Composite indicators are becoming more relevant for evaluating the performance of water companies from a holistic perspective. Some of them are related with economic aspects, and others focus on social and environmental features. Consequently, a multidimensional evaluation is necessary for handling the great amount of information provided by multiple single indicators of a different nature. This paper presents a two-phase approach to evaluate the sustainability of water companies. First, a partial composite indicator for each dimension (social, environmental, economic) is obtained using multi-criteria decision making (MCDM). Then, a global indicator is obtained, in terms of the values reached in the previous stage for every partial indicator, by means an optimization problem rooted in data envelopment analysis (DEA). Our proposal offers the possibility of analyzing the performance of each water company under each dimension that characterizes the concept of sustainability, as well as a... [more]

This study investigates the preferences of Italian home-owners when choosing a new domestic heating system. The focus is on understanding the influence on consumer choice of a potential label certifying the effect of the heating system on the greenhouse effect. To this end, we designed a survey including a discrete choice experiment and administered it to residents in north-eastern Italy. Our findings reveal that, on average, respondents pay particular attention to the green effect of their purchase. The carbon dioxide reduction label was considered second in terms of importance after cost. Further analysis found that our sample presents three clusters of customers, with intra-cluster homogeneous preferences. The cluster analysis showed that while the initial system costs are considered to varying degrees by the whole sample, the carbon dioxide reduction label was considered important by 79% of respondents (members of clusters 1 and 2). To achieve greater results in reducing the greenh... [more]

Recent research has investigated the energy saving potential of regenerative suspension. However, the greenhouse gas (GHG) emission mitigation potential of regenerative suspension in battery electric vehicles (BEVs) has not been considered. Life cycle assessment (LCA) is a typical method for evaluating GHG emissions but is rarely used in vehicle control design. Here we explore the effects of regenerative suspension on reducing the GHG emissions from a BEV, whose control design considers well-to-wheels (WTW) analysis. The work first conducts the WTW analysis and modelling of the GHG emissions from a BEV equipped with regenerative suspension. Based on the models, the relation between suspension control parameters and GHG emissions is obtained. To reach a compromise between dynamic performance and environmental benefit, two types of control parameters are recommended and their switch rules during the operation are proposed. Finally, we take a case study with different driving cycles, road... [more]

Life cycle assessment (LCA) is an established method to assess the various environmental impacts associated with all the stages of a building. The goal of this project was to calculate the environmental releases for a whole office building and investigate the contribution in terms of environmental impact for different parts of the building, as well as the impact from different stages of the life cycle. The construction process was followed up during production and the contractors provided real-time data on the input required in terms of building products, transport, machinery, energy use, etc. The results are presented for five environmental impact categories and, as expected, materials that constitute the main mass of the building and the energy used during operation contribute the largest share of environmental impact. It is usually difficult to evaluate the environmental impact of the materials in technical installations due to the lack of data. However, in this study, the data were... [more]

In this time, energy efficiency (EE), measured in bits per Watt, has been considered as an important emerging metric in energy-constrained wireless communication networks because of their energy shortage. In this paper, we investigate power beacon assisted (PB) energy harvesting (EH) in half-duplex (HD) communication network under co-channel Interferer over Rayleigh fading environment. In this work, we investigate the model system with the time switching (TS) protocol. Firstly, the exact and asymptotic form expressions of the outage probability (OP) are analyzed and derived. Then the system EE is investigated and the influence of the primary system parameters on the system performance. Finally, we verify the correctness of the analytical expressions using Monte Carlo simulation. Finally, we can state that the simulation and analytical results are the same.

Global warming and climate change caused by greenhouse gas (GHG) emissions have rapidly increased the occurrence of abnormal climate events, and both the scale and frequency of geotechnical engineering hazards (GEHs) accordingly. In response, geotechnical engineers have a responsibility to provide countermeasures to mitigate GEHs through various ground improvement techniques. Thus, this study provides a comprehensive review of the possible correlation between GHG emissions and GEHs using statistical data, a review of ground improvement methods that have been studied to reduce the carbon footprint of geotechnical engineering, and a discussion of the direction in which geotechnical engineering should proceed in the future.

The role of flexible alternating current transmission systems (FACTSs) in the provision of grid services is becoming increasingly important, due to the massive integration of intermittent renewable energy sources, energy storage systems, and the decommissioning of thermal plants. A comprehensive literature review of grid services offered by FACTS is performed, focusing on the different grid services that they can provide, such as power flow control, reactive power control, voltage control, power quality improvement, harmonic mitigation, improvement of transient stability, and damping of inter-area and intra-area oscillations. These grid services need to be realistically and economically validated in suitable testing environments. A review of relevant standards, guides, and the literature is performed, which covers the entire range from functional specification and factory testing up to the field testing of FACTS. Advanced industry practices, such as controller hardware in the loop (CHI... [more]

Land use changes have significantly altered the natural environment in which humans live. In urban areas, diminishing air quality poses a large threat to human health. In order to investigate the relationship between land use/cover change (LUCC) and air pollutants of Wuyishan City between 2014−2017, an integrated approach was used by combining remote sensing techniques with a landscape ecology methods. Annual, seasonal, and weekly mean values of air pollutant (SO2, NO2, CO, PM10, O3, PM2.5, black carbon) concentration and atmospheric visibility were calculated to develop a Pearson correlation between LUCC and air pollutants concentration. Results showed an increase in forested areas (1.79%) and water areas (15.89%), with a simultaneous reduction in cultivated land (6.47%), bare land (72.61%), and built-up land (16.03%) from 2014 to 2017. The transition matrix of land use types revealed that (i) forest expansion took place mainly at the expense of cultivated land (13.94%) and bare land... [more]