The purpose of this investigation is to propose a way for acquiring the foremost window allocation scheme to have the best trade-off among energy, environmental, and comfort criteria in a building. An advanced decision-making tool, named the technique for order preference by similarity to ideal solution (TOPSIS), is utilized to find the best building amongst different alternatives for having windows on the building façades. Three conditions, namely two parallel, two perpendicular, and three façades, considered as A, B, and C types, respectively, are investigated. For each type, four possible orientations are studied. Heating, cooling, and lighting energy demands in addition to carbon dioxide equivalent emission and thermal and visual comfort are taken into account as the investigated criteria, and they are all evaluated in a simulation environment. The results show that for the modular residential buildings chosen as the case study and located in Tehran, Iran, having windows on the nor... [more]

This paper investigates a use case of robust anomaly detection applied to the scenario of a photovoltaic production factory—namely, Enel Green Power’s 3SUN solar cell production plant in Catania, Italy—by considering a Monte Carlo based pre-processing technique as a valid alternative to other typically used methods. In particular, the proposed method exhibits the following advantages: (i) Outlier replacement, by contrast with traditional methods which are limited to outlier detection only, and (ii) the preservation of temporal locality with respect to the training dataset. After pre-processing, the authors trained an anomaly detection model based on principal component analysis and defined a suitable key performance indicator for each sensor in the production line based on the model errors. In this way, by running the algorithm on unseen data streams, it is possible to isolate anomalous conditions by monitoring the above-mentioned indicators and virtually trigger an alarm when exceedin... [more]

The energy transformation towards renewable energy sources in the conditions of climate change and the accompanying climate risk is a priority for all countries in the world. However, the degree of advancement of activities in this area varies significantly between countries, which is the result of different activities for renewable energy sources in individual countries. The aim of this article is to determine the trends of changes in the area of the use of renewable energy sources in EU countries. The study uses TMD (taxonomic measure of development) methods and dynamic classification, which allowed to distinguish typological groups of objects with similar dynamics of the studied phenomenon. The EU 28 countries were analyzed. Statistics (Eurostat database) are provided for the period 2004−2019. As a result of the research, it was found that the Scandinavian countries and the countries of Western Europe were characterized by the highest stability in terms of the use of renewable energ... [more]

The effect of reducing particle size on physical properties, the methane yield and energy flow were investigated through the biochemical methane potential (BMP) experiment of aerobic-anaerobic digestion (AAD) of rice straw (RS). The whole straw was crushed through four sieves of different aperture sizes (1, 3, 5, and 7 mm) to obtain the actual and non-uniform particle size distribution (PSD). The results indicated that the actual particle sizes were normally or logarithmic normally distributed. Reducing particle size could significantly promote the aerobic hydrolysis and acidification process, increase the content of volatile fatty acids (VFAs) from 4408.78 to 6225.15 mg/L and the degradation of volatile solids (VS) from 40.56% to 50.49%. The results of path analysis suggested that particle size reduction played an important role in improving lignocellulosic degradability, which was the main factor affecting methane production with the comprehensive decision of 0.4616. The maximum meth... [more]

The design of energy systems is very important in order to reduce operating costs and guarantee the reliability of a system. This paper proposes a new algorithm to solve the design problem of optimal multi-objective redundancy of series-parallel power systems. The chosen algorithm is based on the hybridization of two metaheuristics, which are the bat algorithm (BA) and the generalized evolutionary walk algorithm (GEWA), also called BAG (bat algorithm with generalized flight). The approach is combined with the Ushakov method, the universal moment generating function (UMGF), to evaluate the reliability of the multi-state series-parallel system. The multi-objective design aims to minimize the design cost, and to maximize the reliability and the performance of the electric power generation system from solar and gas generators by taking into account the reliability indices. Power subsystem devices are labeled according to their reliabilities, costs and performances. Reliability hangs on an... [more]

The turbulent pulsating flow and heat transfer in straight and 90° curved square pipes are investigated in this study. Both experimental temperature field measurements at the cross-sections of the pipes and conjugate heat transfer (CHT) simulation were performed. The steady turbulent flow was investigated and compared to the pulsating flow under the same time-averaged Reynolds number. The time-averaged Reynolds number of the pulsating flow, as well as the steady flow, was approximately 60,000. The Womersley number of the pulsating flow was 43.1, corresponding to a 30 Hz pulsating frequency. Meanwhile, the Dean number in the curved pipe was approximately 31,000. The results showed that the local heat flux of the pulsating flow was greater than that of the steady flow when the location was closer to the upstream pulsation generator. However, the total heat flux of the pulsating flow was less than that of the steady flow. Moreover, the instantaneous velocity and temperature fields of the... [more]

Biodiesel is a clean, renewable, liquid fuel that can be used in existing diesel engines without modification as pure or blend. Transesterification (the primary process for biodiesel generation) via heterogeneous catalysis using low-cost waste feedstocks for catalyst synthesis improves the economics of biodiesel production. Heterogeneous catalysts are preferred for the industrial generation of biodiesel due to their robustness and low costs due to the easy separation and relatively higher reusability. Calcium oxides found in abundance in nature, e.g., in seashells and eggshells, are promising candidates for the synthesis of heterogeneous catalysts. However, process improvements are required to design productive calcium oxide-based catalysts at an industrial scale. The current work presents an overview of the biodiesel production advancements using calcium oxide-based catalysts (e.g., pure, supported, and mixed with metal oxides). The review discusses different factors involved in the s... [more]

This study focuses on a modeling framework to support mobility planners and energy providers in the sustainable development of electric mobility in urban areas. Specifically, models are provided to simulate measures for the optimal management of energy demand and thoughtful planning of charging infrastructures in order to avoid congestion on the power grid. The measures, and consequently the models, are classified according to short-term initiatives based on multimodality between electric vehicles and public transport (Park and Ride), as well as medium to long-term initiatives based on the development of an energy-oriented land use of the city. All the models are data-driven, and different sets of floating car data available for the city of Rome (Italy) have been exploited for this aim. The models are currently being implemented in an agent-based simulator for electric urban mobility adopted by the National Agency for Energy and Environment in Italy (ENEA).

The purpose of this study is to compare the load calculation results by a model using the air changes per hour (ACH) method and a model using an airflow network (AFN) and to ascertain what causes the difference between the two models. In the basic case study, the difference in the heat transfer distribution of the model in the interior space was investigated. The most significant difference between the two models is the heat transfer that results from infiltration. Parameter analysis was performed to investigate the relationship between the difference and the environmental variables. The result shows that the greater the difference is between the air temperature inside the balcony and the outdoor air temperature, and the greater the air flows from the balcony to the residential area, and the greater the heating and cooling load difference occurs. The analysis using the actual weather files of five domestic cities in South Korea rather than a virtual case shows that the differences are... [more]

In this work, the problematic identification of the main sources of noise occurring from the exploitation of railway vehicles moving at a speed of 200 km/h were analyzed. Within the conducted experimental research, the testing fields were appointed, measurement apparatus selected, and a methodology for conducting measurements was defined, including the assessment of noise on a curve and straight track for electric multiple units of the so-called Pendolino, an Alstom type ETR610 series ED25 train. The measurements were made using a microphone camera Bionic S-112 at a distance of 22 m from the track axis. As a result of the conducted experimental research, it was indicated that the noise resulting from vibrations arising at the wheel-rail contact (rolling noise) was the dominant source of sound.

Polyimide is a high-performance engineering polymer with outstanding thermomechanical properties. Because of its inherent fire-retardant properties, polyimide nanocomposite is an excellent material for packaging electronic devices, and it is an attractive electrode material for batteries and supercapacitors. The fire-retardant behavior of polyimide can be remarkably improved when polyimide is reinforced with multilayered graphene sheets. Differential scanning calorimetry and thermogravimetric analysis were used to study the heat of decomposition and gravimetric decomposition rate, respectively, of polyimide-graphene nanocomposites. Polyimide/graphene nanocomposites containing 10, 20, 30, 40, and 50 wt.% of multilayered graphene sheets were heated at a rate of 10 and 30 °C/min in air and in nitrogen atmosphere, respectively. The rate of mass loss was found to remarkably decrease by up to 198% for nanocomposites containing 50 wt.% of graphene. The enthalpy change resulting from the decom... [more]

Due to the rising water deficit in agriculture, digestate is increasingly being considered not only as an alternative fertiliser but also as a potential source of water. The use of recycled water for crop irrigation requires that it be treated in such a way that contaminants from the fermented biomass are not returned to the environment. Membrane processes can provide promising results in this regard. This study seeks to achieve membrane filtration using flat ceramic membranes for effective digestate liquid fraction treatment from a municipal waste biogas plant. Membranes of 1, 5, 15, and 50 kDa, and 0.14 and 0.45 µm are examined. The results obtained show that the application of a sedimentation process, as a preliminary step in the purification of the digestate, allows for a significant reduction in the content of contaminants in the solution. By analysing the effectiveness of the liquid fraction of the digestate purification in the sedimentation-membrane filtration process using flat... [more]

The present study reports the development of a deep learning artificial intelligence (AI) model for predicting the thermal performance of evaporative cooling systems, which are widely used for thermal comfort in different applications. The existing, conventional methods for the analysis of evaporation-assisted cooling systems rely on experimental, mathematical, and empirical approaches in order to determine their thermal performance, which limits their applications in diverse and ambient spatiotemporal conditions. The objective of this research was to predict the thermal performance of three evaporation-assisted air-conditioning systems—direct, indirect, and Maisotsenko evaporative cooling systems—by using an AI approach. For this purpose, a deep learning algorithm was developed and lumped hyperparameters were initially chosen. A correlation analysis was performed prior to the development of the AI model in order to identify the input features that could be the most influential for the... [more]

While joining the European Union (EU) in 2004, the countries of the Visegrad Group (V4) had to face a major challenge in the context of adapting to the EU standards in the field of energy use and energy efficiency. One of the sectors that heavily depends on the use of energy (mainly from fossil fuels) is the food production system, whose energy transformation is essential for future food security. The study aimed to measure the use of energy and its structures in the food production systems of the V4 countries and the EU-15 countries in relation to the implementation of the EU energy targets. The targets assumed, among other things, a reduction in overall energy use and an increase in the share of renewables in the energy mix. The proprietary method based on the assumptions of lifecycle assessment was applied to measure energy consumption in the food production systems with the use of input−output tables and energy accounts, which are part of the World Input−Output Database. The resear... [more]

The identification of extreme wind events and their driving forces are crucial to better integrating wind generation into the power system. Recent work related the occurrence of extreme wind events with some weather circulation patterns, enabling the identification of (i) wind power ramps and (ii) low-generation events as well as their intrinsic features, such as the intensity and time duration. Using Portugal as a case study, this work focuses on the application of a weather classification-type methodology to link the weather conditions with wind power generation, namely, the different types of extreme events. A long-term period is used to assess and characterize the changes in the occurrence of extreme weather events and corresponding intensity on wind power production. High variability is expected under cyclonic regimes, whereas low-generation events are most common in anticyclonic regimes. The results of the work provide significant insights regarding wind power production in Portu... [more]

Important factors controlling the effective utilization of geothermal energy are favorable reservoir properties of rock formations, which determine both the availability and the transfer opportunities of reservoir fluids. Hence, crucial to the successful utilization of a given reservoir is the preliminary recognition of distribution of reservoir parameters as it enables the researchers to select the prospective areas for localization of future geothermal installations and to decide on their characters. The objectives of this paper are analyses and discussion of the properties of quartz sandstones buried down to a depth interval from about 3000 to under 5000 m below surface. These sandstones belong to Ediacaran−Lowery Cambrian Łeba, Kluki and Żarnowiec formations. The source data from the Słupsk IG-1 provided the basis for 1D reconstruction of burial depth and paleothermal conditions as well as enabled the authors to validate of the results of 2D models. Then, porosity distribution with... [more]

Banks Strait, Tasmania, Australia, has been identified as a potential site for the deployment of tidal turbines. In this study, the characterization of sediment transport and large sand waves for this site is performed. Observations of bed level change collected from surveys in 2018 showed a migration of large sand waves over a period of nine months. Migration rates in an excess of one hundred meters for nine months were found, which are large compared to the rate reported at other coastal sites, by several meters per year. A validated hydrodynamic model is coupled with a morphodynamic model to perform sensitivity tests and identify what parameters influence migration to better understand sediment dynamic in the Banks Strait. Numerical analysis showed a constant shift of the sand waves profile in an eastward direction, consistent with the observations. This migration was strongly linked with tidal asymmetry, with a residual current flowing towards the east. The principal parameters dri... [more]

To host the 2022 FIFA World Cup, Qatar is facing the greatest challenge in balancing the energy consumptions for cooling the stadiums and the thermal comfort for both players and spectators. Previous studies have not considered using a combined configuration of air curtain and roof cooling supply slot in stadiums to prevent the infiltration of outside hot air and reduce the cooling system’s energy consumption. This paper presents a Computational Fluid Dynamics (CFD) study of thermal and wind modeling around a baseline stadium and simulates the cooling scenarios of air curtains and roof cooling along with the energy consumption estimations for the World Cup matches using Building Energy Simulation (BES). Sensitivity analysis of different supply speeds and supply temperatures of air curtain gates and roof cooling was carried out, and the results showed that scenario six, which provides supply air of 25 m/s and 20 m/s at the roof and air curtain gates with a supply temperature of 10 °C, d... [more]

Shifting from fossil to renewable energy sources is a major global challenge, and in this context, the European Union has promoted sustainable and environmentally friendly growth as early as the Maastricht Treaty of 1992. To date, European institutions have promulgated a series of environmental regulations and directives aimed at promoting and imposing adoption by member states of internal regulations. This paper is focused on Western Europe, and it explores, for each state under analysis, energy policies adopted, the results achieved and recommendations for the future growth of renewable energy. The results show that in countries where energy policy is not fragmented, the yield in renewable energies has been higher, and also in the states where more and various forms of subsidies are foreseen, growth seems to be greater. Finally, the paper provides useful recommendations and future policy implications for states that have not met the 2020 targets.

The article analyses energy and environmental operating parameters of a compression ignition internal combustion engine running on HVO-biobutanol and castor oil fuel blends, also comparing them with parameters of an engine running on convection diesel. Since biobutanol is known for poor lubrication characteristics, it was mixed with 5% of castor oil. The obtained blend of biobutanol and castor oil was mixed with HVO at 2/95, 10/90, and 20/80 v/v and fed to the compression ignition internal combustion engine. The presented physicochemical indicators justified the use of the said fuel blends. Constant engine crankshaft speed of 2000 rpm and a variable load expressed as BMEP of 0.1−0.9 MPa was selected in the research. When using the biobutanol−castor oil additive (hereafter simply biobutanol additive) in HVO, an increase in the rate of heat release (ROHR) and the convergence of its value to that of to conventional diesel fuel was observed. A decrease in BTE values was also observed with... [more]

Cu(In,Ga)Se2 (or CIGS) thin films and devices were fabricated using a modified three-stage process. Using high deposition rates and a low temperature during the process, a copper chloride vapor treatment was introduced in between the second and third stages to enhance the films properties. X-ray diffraction and scanning electron microscopy demonstrate that drastic changes occur after this recrystallization process, yielding films with much larger grains. Secondary ion mass spectrometry shows that the depth profile of many elements is not modified (such as Cu, In and Se) while others change dramatically (such as Ga and Na). Because of the competing effects of these changes, not all parameters of the solar cells are enhanced, yielding an increase of 15% in the device efficiency at the most.

Inducing spanwise motions in the vicinity of solid boundaries alters the energy, mass and/or momentum transfer. Under some conditions, these motions are such that drag is reduced and/or transition to turbulence is delayed. There are several possibilities to induce those spanwise motions, be it through active imposition a predefined velocity distribution at the walls or by careful design of the wall shape, which corresponds to passive control.In this contribution, we investigate the effect that wavy walls might have on delaying transition to turbulence. Direct Numerical Simulation of both planar and wavy-walled channel flows at laminar and turbulent regimes are conducted. A pseudo laminar regime that remains stable until a Reynolds number 20% higher that the critical is found for the wavy-walled simulations. Dynamic Mode Decomposition applied to the simulation data reveals that in these configurations, modes with wavelength and frequency compatible with the surface undulation pattern ap... [more]

The aim of the study was to assess leaching of Cl−, SO42−, and PO43− from ashes formed in household furnaces. The ashes were obtained following the combustion of conventional fuels, namely wood and hard coal, and alternative fuels with various fractions of municipal waste in a household boiler. Aqueous leachates of the ashes were used to determine concentrations of chlorides by titration (Mohr’s method) (21.3−3049.6 mg/dm3), sulphates by the gravimetric method (12.2−244.1 mg/dm3), and phosphates by spectrophotometry (0.01−67.2 mg/dm3). It was found that co-combustion of municipal waste with plastic-coated paper cartons, diapers, or a mixed waste fraction leaves the greatest amount of ashes on the furnace grate. The highest amounts of Cl−, SO42−, and PO43− were leached from ashes generated from burning a mix of wood and coals, or wood alone (different species). The addition of municipal waste to the process of burning the conventional and alternative fuels studied did not significantly... [more]

This paper presents an inductive power transfer system on the basis of a double single-phase three-level T-type inverter and two split transmitting coils for constant current and constant voltage wireless charging of low-voltage light electric vehicle batteries with closed-loop control, considering time-delay communication constraints. An optimal control structure and a modified control strategy were chosen and implemented to the wireless power transfer system as a result of a review and analysis of existing solutions. The control system analysis and adjustment of the coefficients of the regulator using Laplace transform were performed. Our study addressed the behavior of the control system with different time delays as well as the dynamic response of the system. The detecting algorithm of a secondary coil was proposed, which ensured efficient system operation and increased the functionality, safety and usability of the device. The efficiency of energy transfer of 90% was reached at th... [more]

The purpose of the study is to identify factors affecting the intention to change an energy supplier. This is in a country, Poland, where competition in the energy market has been intensifying over several years, but incumbent suppliers still have an extremely strong position on the market, and the tendency to change an energy supplier is relatively low. The survey was conducted in 2020 on a sample of 1216 adults. The research results were used for a multigroup SEM (Structural Equation Modelling) analysis using AMOS 26. The main findings indicated a strong impact on a general image of a company, as well as the lack of importance of a green image of the current energy supplier. In the general research approach, there are no visible differences in the impact of the perceived price transparency on the intention to switch the supplier. However, taking into consideration two groups (a low energy bill vs. a high energy bill), some interesting differences are visible. In the markets with low... [more]