The present investigation project aims to evaluate the extraction of contaminant material from two settling ponds to be used as alternative fuel in two cement plants. The extraction is carried out through mechanical means, and after that extraction, two options are compared: energy recovery and incineration. Through energy recovery, a potentially contaminated area is decontaminated and its waste is used; its high calorific value makes this option a viable one. The waste extraction is carried out through mechanical means due to the high density and viscosity of the waste. Because of these characteristics, the waste undergoes an on-site security adaptation to stabilize it, reduce declivity risk and make it suitable to be handled and moved. The second treatment is carried out in external installations where the final product is obtained (alternative fuel), which is to be used at industrial kilns. The entire described process shows a difference on the consumed energy of 6060.42 kWh/twaste... [more]

The harsh operating environment aggravates the degradation of pumped storage units (PSUs). Degradation trend prediction (DTP) provides important support for the condition-based maintenance of PSUs. However, the complexity of the performance degradation index (PDI) sequence poses a severe challenge of the reliability of DTP. Additionally, the accuracy of healthy model is often ignored, resulting in an unconvincing PDI. To solve these problems, a combined DTP model that integrates the maximal information coefficient (MIC), light gradient boosting machine (LGBM), variational mode decomposition (VMD) and gated recurrent unit (GRU) is proposed. Firstly, MIC-LGBM is utilized to generate a high-precision healthy model. MIC is applied to select the working parameters with the most relevance, then the LGBM is utilized to construct the healthy model. Afterwards, a performance degradation index (PDI) is generated based on the LGBM healthy model and monitoring data. Finally, the VMD-GRU prediction... [more]

Fibre optic cables are widely used as communication cables in Instrumentation and Control (I&C) systems. In the case of nuclear power plants (NPPs), using optic cables in mild environments outside of containment areas are very common. However, at present, there is a need for fibre optic cables to be used in containment areas, i.e., with radiation. An optical fibre consists of a highly transparent core that possesses a higher refractive index than the surrounding transparent cladding, which possesses a lower refractive index. Most optical fibres are manufactured from glass (silica with required dopants) which is created at high temperatures from the reaction between gasses. The glass used in optical fibres is sensitive; it becomes dark during exposure to radiation, which compromises the optic functions. That is why there has been a slow infiltration of optic cable in NPP containment areas. Radiation resistant optic fibres have been developed. Although these fibres are called “radiation... [more]

The main objective of the article is to evaluate the investment activity of large cities in Poland in the area of developing a low-carbon economy in 2014−2020, co-financed by European Union funds. This article poses several research questions, namely: Do large cities with environmental problems actively obtain EU funding to develop a low-carbon economy? What are the main socio-economic and environmental determinants of the level of the EU funding absorption among large cities in the research area? The empirical research was conducted on the basis of the data from the Ministry of Investment and Economic Development in Poland, which is responsible for the implementation of cohesion policy funds and from the Local Data Bank of Statistics Poland. Under the 2014−2020 perspective, 223 such projects have been implemented for a total of PLN 21 billion (EUR 4.74 billion). The projects focused on: transportation, electricity, gaseous fuels, steam, hot water and air for air conditioning systems,... [more]

Diesel generators (DGs) are set to work as a backup during power outages or support the load in remote areas not connected to the national grid. These DGs are working at a constant speed to produce reliable AC power, while electrical energy demand fluctuates according to instantaneous needs. High electric loads occur only for a few hours a day in remote areas, resulting in oversizing DGs. During a low load operation, DGs face poor fuel efficiency and condensation of fuel residues on the walls of engine cylinders that increase friction and premature wear. One solution to increase combustion efficiency at low electric loads is to reduce diesel engine (DE) speed to its ideal regime according to the mechanical torque required by the electrical generator. Therefore, Variable Speed Diesel Generators (VSDGs) allow the operation of the diesel engine at an optimal speed according to the electrical load but require additional electrical equipment and control to maintain the power output to elect... [more]

Developing biomass energy, seen as the most important renewable energy, is becoming a prospective solution in attempting to deal with the world’s sustainability-related challenges, such as climate change, energy crisis, and carbon emission reduction. As one of the most promising second-generation energy crops, giant silvergrass (Miscanthus × giganteus) is highly valued for its high potential for biomass production and low maintenance requirements. Mapping the potential global distribution of marginal land suitable for giant silvergrass is an essential prerequisite for the development of giant silvergrass-based biomass energy. In this study, a boosting regression tree was used to identify the marginal land resources for giant silvergrass cultivation using influencing factors, which include climate conditions, soil conditions, topography conditions, and land use. The results indicate that there are 3068.25 million hectares of land resources worldwide suitable for giant silvergrass cultiv... [more]

The current climatic scenario requires the use of innovative solutions to increase the production of electricity from renewable energy sources. Multilevel Power Inverters are a promising solution to improve the penetration of renewable energy sources into the electrical grid. Moreover, the performance of MPIs is a function of the modulation strategy employed and of its features (modulation index and switching frequency). This paper presents an extended and experimental analysis of three-phase five-level Cascaded H-Bridges Multilevel Inverter performance in terms of efficiency and harmonic content considering several MC PWM modulation strategies. In detail, the CHBMI performance is analyzed by varying the modulation index and the switching frequency. For control purposes, the NI System On Module sbRIO-9651 control board, a dedicated FPGA-based control board for power electronics and drive applications programmable in the LabVIEW environment, is used. The paper describes the modulation s... [more]

The article applies a three-stage Slacks-Based Measure-Data Envelopment Analysis (SBM-DEA) pattern to examine the relationship between energy consumption and unfavorable CO2 emissions on green sustainable development, for the 11 cities of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) during 2010−2016, by going through various violated factors and stochastic disturbance. Labor, capital and energy resource are chosen as input variables, while GDP and CO2 emission as output variables. During the three phases consisting of the SBM-DEA model (first stage and third stage) and SFA analysis (second stage), CO2 emission is considered as an unfavorable outcome, while stochastic statistical disturbances and external environmental influences are identified. The results show that the average efficiency of the GBA cities is 0.708, with only Shenzhen, Macao SAR and Hong Kong SAR having an efficiency of 1 during the whole study period. Based on the findings, suggestions are made for the GBA cit... [more]

Smart building issues are critical for current energy and comfort managing aspects in built environments. Nevertheless, the diffusion of smart monitoring solutions via user-friendly graphical interfaces is still an ongoing issue subject to the need to diffuse a smart building culture and a low-cost series of solutions. This paper proposes a new low-cost IoT sensor network, exploiting Raspberry Pi and Arduino platforms, for collecting real-time data and evaluating specific thermal comfort indicators (PMV and PPD). The overall architecture was accordingly designed, including the hardware setup, the back-end and the Android user interface. Eventually, three distinct prototyping platforms were deployed for initial testing of the general system, and we analysed the obtained results for different building typologies and seasonal periods, based on collected data and users’ preferences. This work is part of a large educational and citizen science activity.

Fly ash is the main by-product of coal combustion characterized by a large specific surface area. In addition to oxides, it also contains unburned coal and trace elements. This study aimed to investigate the possibility of using fly ash from pit-coal combustion (CFA) for the treatment of benzene-contaminated soil (S). The CFA was used as a mixture with Portland cement (PC) (70% PC + 30% CFA). The soil was treated with a PC-CFA mixture in amounts of 40, 60, and 80% of soil mass. During the process, the concentration of benzene was monitored with the flame-ionization detector. Produced monoliths (S+(PC-CFA)x) were tested for compressive strength and capillary water absorption. The experiment confirmed that the PC-CFA mixture limited benzene emission. The highest reduction in benzene concentration (34−39%) was observed for samples treated with the PC-CFA mixture in an amount of 80% (S+(PC-CFA)80). The average compressive strength of monoliths S+(PC-CFA)40, S+(PC-CFA)60, and S+(PC-CFA)80 w... [more]

Currently, in conditions of Industry 4.0, the use of cyber-physical systems in various fields is becoming widespread. This article is devoted to the problem of estimating CPS sustainability in the context of modern challenges faced by decision makers and IT developers in order to ensure effective proactive business process management using this innovative technology. The purpose of the research is to propose and substantiate a methodology for estimating CPS sustainability to ensure the reliability and strength of its elements, their interrelationships and interaction, as well as the effective functioning and development of this system in conditions of high dynamism and uncertainty of the external environment. In this study, we used methods of integral evaluation, synthesis, expert assessments, dynamic analysis, and systematic approach, and coined the term ‘CPS sustainability’. Our study showed that negative risks, external and internal threats may have a significant adverse impact on C... [more]

This study examines the concentrations of air pollution in the vicinity of a combined heat and power plant (CHP) and a communication route, using computer modeling of pollutant dispersion and spatial analysis based on real measurements in the city of Łódź, Poland, Europe. The research takes into account the concentrations of particulate matter (PM10, PM2.5, PM1.0) and gaseous pollutants (SO2 and VOC) in winter and summer. The spatial distribution of pollutants is discussed, including the presence of areas with increased accumulations of pollutants. Because atmospheric air has no natural boundaries, when analyzing any location, not only local sources of pollution, but also background pollution, should be analyzed. A clear difference was observed between the concentrations of pollutants in the summer and winter seasons, with significantly higher concentrations in the winter (heating) period. The impacts of road transport, individual heating systems, and combined heat and power plants wer... [more]

Taking a plateau high-pressure common-rail diesel engine as the research model, a model was established and simulated by AVL FIRE according to the structural parameters of a diesel engine. The combustion and emission characteristics of D, B20, and B50 diesel engines were simulated in the plateau atmospheric environment at 0 m, 1000 m, and 2000 m. The calculation results show that as the altitude increased, the peak in-cylinder pressure and the cumulative heat release of diesel decreased with different blending ratios. When the altitude increased by 1000 m, the cumulative heat release was reduced by about 5%. Furthermore, the emission trend of NO, soot, and CO was to first increase and then decrease. As the altitude increased, the mass fraction of NO emission decreased. As the altitude increased, the mass fractions of soot and CO increased. Additionally, when the altitude was 0 m and 1000 m, the maximum temperature, the mass fraction of OH, and the fuel−air ratio of B20 were higher and... [more]

Reservoir formation waters typically contain scaling ions which can precipitate and form mineral deposits. Such mineral deposition can be accelerated electrochemically, whereby the application of potential between two electrodes results in oxygen reduction and water electrolysis. Both processes change the local pH near the electrodes and affect the surface deposition of pH-sensitive minerals. In the context of the plugging and abandonment of wells, electrochemically enhanced deposition could offer a cost-effective alternative to the established methods that rely on setting cement plugs. In this paper, we tested the scale electro-deposition ability of six different formation waters from selected reservoirs along the Norwegian continental shelf using two experimental setups, one containing CO2 and one without CO2. As the electrochemical deposition of scaling minerals relies on local pH changes near the cathode, geochemical modelling was performed to predict oversaturation with respect to... [more]

Since the publication of the first comprehensive Probabilistic Safety Assessment (PSA) study—known as WASH-1400—in the US, PSA has developed into an effective and systematic method of identifying hazards, and evaluating and prioritizing the risks in nuclear facilities [...]

Ammonia combustion is a promising energy source as a carbon free fuel without greenhouse gas emissions. However, since the auto-ignition temperature is 651 degrees Celsius and the range of flammability limit is not wide compared to other fuels, fundamental studies on ammonia fires have rarely been conducted so far. Therefore, this study aims to numerically estimate fire spread characteristics when ammonia fuel in a high-pressure state leaks to the outside, especially focusing on the flammability limit according to oxygen concentration. Three kinds of reaction mechanism for numerical analysis were adopted to compare the flame structure, flammability limit, and combustion characteristics. Plank-mean absorption coefficients of nitrogen species were taken for the radiation model, in addition to the optically thin model. The effect of radiation heat loss could be identified from the maximum flame temperature trend at a low strain rate. It was confirmed that the pyrolysis of ammonia in the p... [more]

A synthetic review of the application of multi-objective optimization models to the design of climate-responsive buildings and neighbourhoods is carried out. The review focused on the software utilized during both simulation and optimization stages, as well as on the objective functions and the design variables. The hereby work aims at identifying knowledge gaps and future trends in the research field of automation in the design of buildings. Around 140 scientific journal articles, published between 2014 and 2021, were selected from Scopus and Web of Science databases. A three-step selection process was applied to refine the search terms and to discard works investigating mechanical, structural, and seismic topics. Meta-analysis of the results highlighted that multi-objective optimization models are widely exploited for (i) enhancing building’s energy efficiency, (ii) improving thermal and (iii) visual comfort, minimizing (iv) life-cycle costs, and (v) emissions. Reviewed workflows dem... [more]

Willows are one of the plants which can be used to produce biomass for energy purposes. Biomass production is classified as a renewable energy source. Increasing the share of renewable sources is one of the priority actions for European Union countries due to the need to reduce greenhouse gas emissions. To achieve the best possible growth of the willow and increase its biomass for fuel, it is crucial to provide optimal water conditions for its growth. The aim of the study was to determine the water requirements of willows under the conditions of the western Polish climate and to verify whether this area is potentially favourable for willow cultivation. The novelty of this paper lies in its multi-year climatic analysis in the context of willow water needs for the area of three voivodships: Lubusz, Lower Silesian, and West Pomeranian. This is one of the few willow water-needs analyses for this region which considers the potential for widespread willow cultivation and biomass production i... [more]

This paper focuses on a detailed numerical investigation combined with experimental research for a non-premixed swirl combustor, which aims to analyze the effects of the blade angle of the outer swirler and equivalence ratio on flow and combustion characteristics. In the experiment, the temperature in the furnace was obtained with a thermocouple, while a realizable k-ε turbulence model and two-step reaction mechanism of methane and air are used in the numerical method. The calculation results are in good agreement with the experimental data. The results reveal that the air flow rate through the swirler accounts for a small amount of the total air due to the influence of the draft fan, and there is no central recirculation zone (CRZ) despite the presence of the swirler. It was also found that NO emissions gradually decrease as the blade angle of the outer swirler increases. It was also indicated that the average temperature is 100 K higher than the general combustor with a 58° blade ang... [more]

In order to achieve Australia’s greenhouse gas emissions reduction targets, a majority of the existing residential building stock in Australia will require retrofitting in favour of energy-efficient solutions. This paper considers retrofitting for conditioning to be one of the most straightforward and offers the greatest potential to deliver significant comfort and energy-saving results. Radiant conditioning systems are not new, yet some game-changing innovations have taken place over the last decade that may require an entire paradigm shift in the manner we condition our buildings. The reiteration of the principle ‘thermally active systems’ suggests that our buildings need to accommodate these systems into the fabric of building components. However, extremely few products and/or innovative solutions for doing such seem to be provided by the industry. We seem incompetent with solutions that are not costing the Earth, insulating, lightweight, and offering an instant response time to con... [more]

Climate change and environmental pollution are considered to be among the main challenges faced by the modern world. The growth of environmental awareness and the adoption of a pro-environmental approach are considered to be the key megatrends with the greatest impact on the global economy in the upcoming years. According to Eurobarometer, EU citizens are particularly aware of the importance of protecting the environment. Although the negative environmental impact of European industry has improved over the past decades, EU citizens believe that there is further scope in terms of helping companies transition towards adopting more sustainable models. One of the factors contributing to the reduction in negative environmental impact is the participation of enterprises in voluntary programs such as the Environmental Management System (EMS), according to ISO 14001, or the Eco-management and Audit Scheme (EMAS). The whole population of Polish companies registered under the EMAS was included i... [more]

The performance of the air-cooler in refrigeration systems plays a key role in their energy efficiency. Here, the plenum-chamber coefficient was defined to investigate a possible way of enhancing the refrigeration coefficient that reflects the efficiency of the system. To investigate the influence of the plenum-chamber coefficient on the frosting and the cooling system of the air-cooler, three plenum-chamber coefficients (0.74, 0.97, 1.2) were studied under two different relative humidities. The temperature decreasing curve of the environmental chamber, the velocity distribution of the air-cooler, and the frost accumulation under and on the air-cooler were analyzed. We find that the homogeneity of the velocity distribution of the air-cooler and the frost accumulation increase with a growing plenum-chamber coefficient, while the frost accumulation on the fin will first increase and then decrease with the increase in the plenum-chamber coefficient. In general, frosting is more present wh... [more]

Solid circulation rate (Gs) represents the mass flux of circulating particles in circulating fluidized bed (CFB) systems and is a significant parameter for the design and operation of CFB reactors. Many measuring technologies for Gs have been proposed, though few of them can be applied in industrial units. This paper presents a comprehensive study on measuring technologies, and the results indicate that though the accumulation method is most widely applied, it is constrained by the disturbance of normal particle circulation. Some publications have proposed mathematic models based on pressure drop or other parameters to establish Gs measurement models; these necessitate the accurate modeling of complicated gas-solid flows in industrial devices. Methods based on certain measurement devices to specify parameters like velocity require device endurance in the industrial operation environment and stable local gas-solid flow. The Gs measuring technologies are strongly influenced by local gas-... [more]

The aim of the study is to draw attention to the fact that reducing methane and nitrous oxide emissions as a result of traditional manure storage for several months in a pile is not only a non-ecological solution, but also unprofitable. A solution that combines both aspects—environmental and financial—is the use of manure as a substrate for a biogas plant, but immediately—directly after its removal from the dairy barn. As part of the case study, the energy and economic balance of a model farm with dairy farming for the scenario without biogas plant and with a biogas plant using manure as the main substrate in methane fermentation processes was also performed. Research data on the average emission of ammonia and nitrous oxide from 1 Mg of stored manure as well as the results of laboratory tests on the yield of biogas from dairy cows manure were obtained on the basis of samples taken from the farm being a case study. The use of a biogas installation would allow the emission of carbon dio... [more]

Because of rapid urbanization, traffic problems, and other factors, underground spaces have been used more in the twenty-first century. Large underground spaces are required for underground city, metro, tunnel, mine, industrial and agricultural engineering, and civil air defense engineering. Underground spaces with varying thermal, ventilation, and lighting environments can face problems of comfort, health, and safety. High temperatures, high humidity, difficulty in flue gas emission, harmful microorganisms, radon, and physical and psychological problems are examples of issues. Air quality control technologies for underground spaces, such as ventilation, dehumidification, natural energy utilization, smoke extraction, and ventilation resistance reduction, are discussed. Ventilation for smoke-proofing/evacuation is also extensively addressed.