Palm oil is, from an economic, environmental, and social point of view, a vegetable oil with great potential and the state of Pará-Brazil is Brazil’s great producer. In addition, soap phase residue or palm oil neutralization sludge (PONS), a byproduct of the neutralization step of the chemical refinement of palm oil, is produced, posing a huge problem for waste disposal and management in the production process of refined palm oil (RPO). In this context, this work aims to systematically investigate the economic analysis of the thermal−catalytic process of crude palm oil (CPO) and palm oil neutralization sludge (PONS). The thermocatalytic processes of CPO and PONS carried out at pilot scale and their economic feasibility were analyzed. The yields of biofuels produced by fractional distillation were also presented. The physicochemical properties of CPO and PONS, as well as those of organic liquid products obtained by the thermal−catalytic process of CPO and PONS were taken into account in... [more]

This study investigates the possibility of applying a large-scale solar updraft tower power plant in India with local ground conditions as an environmentally friendly and economically viable energy source. A reference model Solar Updraft Tower Power Plant (SUTPP) is constructed to examine the influence of the most prominent plant dimensional parameters, including collector radius (RCollector), tower height (HTower), and tower radius (RTower) with dimensional limits and intervals on the power output of the SUTPP. Udat, Rajasthan, India, is used as a reference location for meteorological conditions to evaluate SUTPP power output equations for a ranging power output, with position coordinates of 27°35′ and 72°43′. Multiple simulations for the objective function are carried out, and the outcomes are compared to the optimized dimensions of each set of plants. The model examines the effect of variation in ambient, plant geometry, and material conditions on power output and analyzes efficienc... [more]

The six-pole radial−axial hybrid magnetic bearing (RAHMB) has the advantages of small space and low power consumption, making it suitable for flywheel batteries. The bearing capacity and the volume are the main specifications of magnetic bearings that should be considered comprehensively. In this work, the six-pole RAHMB was used in a horizontal flywheel battery. As the axial bearing capacity is relatively smaller than the radial bearing capacity, a design method with independent radial and axial bearing capacity is proposed, and the parameters are optimized to minimize the volume. The mathematical model of six-pole RAHMB was derived from the equivalent magnetic circuit method. The relationships between bearing capacity, biased flux density, saturation flux density and the section area of magnetic poles were analyzed. The basic principle of the design method with independent radial and axial bearing capacity is to determine which five of the variables are preferred. According to the de... [more]

The energy autonomy of UAVs is an important direction in the field of aerospace. Long-endurance aerial vehicles allow for continuous flight; however, to meet the guidelines, the power supply system has to be able to harvest energy from outside. Solar cells allow the production of electricity during the day when the sun shines on their surface. Depending on the location, time, weather, and other external factors, the energy produced by PV panels will change. In order to calculate as accurately as possible the energy obtained by solar cells, we developed a simulation model that took into account all of the external restrictions and the UAV’s limits during flight. The conducted analysis made it possible to obtain information for the specific input data on whether the UAV is able to fly for 24 h in a specific flight scenario. The UAV powered by solar cells developed by us and the performed aviation missions have shown that the UAV is capable of continuous flight without the need to land.

The most significant geo-energy sources in the world today continue to be oil, gas, and geothermal reservoirs. To increase oil and gas reserves and production, new theories are constantly being developed in the laboratory and new technologies are being applied in the oilfield. This Special Issue compiles recent research focusing on cutting-edge ideas and technology in oil, gas, and geothermal reservoirs, covering the fields of well drilling, cementing, hydraulic fracturing, improved oil recovery, conformance control, and geothermal energy development.

The constant development of civilization increases environmental pollution as a result of industrial activity and transport. Consequently, human activity in this area is restricted by regulations governing the permissible emission of harmful substance components into the environment. These include substances emitted by combustion engines, the use of which remains high in many industries. Consequently, research is being conducted to reduce the emissions of harmful exhaust components from existing and newly manufactured internal combustion engines. This research presents a used semi-truck engine, in which an innovative Compressed Natural Gas (CNG) supply system was applied. Using this fuel supply installation allows a mass exchange of the base diesel fuel to natural gas of up to 90%. The study evaluated the effect of the diesel/CNG exchange ratio for different engine operating conditions (engine load, speed) on the concentration of toxic components, such as CO, NO, NO2, NOX, as a sum of... [more]

Given the importance of renewable energy sources in distribution systems, this article addresses the problem of locating and determining the capacity of these sources, namely, wind turbines and solar panels. To solve this optimization problem, a new algorithm based on the behavior of salp is used. The objective functions include reducing losses, improving voltage profiles, and reducing the costs of renewable energy sources. In this method, the allocation of renewable resources is considered for different load models in distribution systems and different load levels using smart meters. Due to the fact that these objective functions are multi-objective, the fuzzy decision-making method is used to select the optimal solution from the set of Pareto solutions. The considered objective functions lead to loss reduction, voltage profile improvement, and RES cost reduction (A allocating RES resources optimally without resource limitations; B: allocating RES resources optimally with resource lim... [more]

Due to the prospect of climate change and the challenges posed by the European Union to the modern power grid, a decentralized system based on distributed energy sources is being created from a centralized system based on utility power. It also involves new ideas on the operation and management of power grids, especially at the level of low-voltage distribution networks, where prosumers play a special role. In addition to the transformation of sources to renewables, the aim is to increase the flexibility of power grids by exploiting the regulatory potential of flexible grid components. The issue of grid flexibility assumes particular importance in the case of microgrids and local grids covered by the energy communities. Many posts describe the realization of the task of flexibility through energy storage, e.g., storing storage resources in electric vehicles or the use of energy transformation through conversion to heat, air compression air, or process cooling. However, there seems to b... [more]

The purpose of conducted research was to recognize factors determining households’ Energy transition and barriers that slow that process. Energy transition itself, understood as a shift in the structure of fuels used in energy production and technological changes related to its use, are key elements of shaping the economy. It was determined to what extent existing household renewable energy installations meet the energy needs of their residents and what factors encourage their installation. In addition, barriers limiting energy transition as perceived by household members were identified. The research used data from the EUROSTAT and the results of surveys conducted using the CAWI (Computer-Assisted Web Interview) and PAPI (Paper and Pencil Interview) techniques among households in Poland. The methods of descriptive statistics, the chi-square test of independence, the Kruskal−Wallis ANOVA test, the Mann−Whitney U test and logistic regression were used to analyze the research results. Th... [more]

Transforming the transport sector to zero emission is an integral part of changes to the energy sector worldwide. This effects not only the electrification of the private sector but also the commercial sector. The aim of this study is to develop methodologies, algorithms and associated requirements for the integration of electric vehicles into a logistics application with a possible reduction in operating costs. The most favorable solution for a company was evaluated using the analytic hierarchy process algorithm considering three main aspects: economic, environmental and technical. An analysis of the environmental impact of the vehicle fleet in terms of atmospheric emissions was also conducted, based on the data available for combustion and electric vehicles, considering the well-to-tank approach. The costs associated with operating an electric vehicle were identified and compared to the current costs associated with operating a standard diesel-based fleet. Incorporating the identifie... [more]

In a battery cooling system, by adopting a cooling optimization control strategy, the battery temperature under different external environments and load currents can be adjusted to ensure performance and safety. In this study, two modes of the thermal management system are established for the 6s4p (six serial and four parallel batteries in a stage) battery pack. A single particle model, considering battery aging, is adopted for the battery. Furthermore, a cooling optimization control strategy for the battery is proposed based on the triple-step nonlinear method, and then the optimization effect is validated under two C-rate charge−discharge cycles, NEDC cycles, and US06 cycles. Moreover, an extended PID control strategy is constructed and compared with the triple-step nonlinear method. A comparison of pump power, thermal behavior, and aging performance indicate parallel cooling is more advantageous. This verifies the validity of the triple-step nonlinear method and shows its advantages... [more]

Tight oil and gas resources are widely distributed and play an important role in the petroleum industry. Due to its nanoscale pore-throat characteristics, the capillary effect is remarkable, and spontaneous imbibition is very beneficial to the development of low-permeability reservoirs. In this study, the imbibition experiments of 2D nano blackcard, nanoemulsion, and water were carried out, respectively. The pore-throat fluid distribution characteristics before and after core imbibition were analyzed with nuclear magnetic resonance technology, and the enhanced oil recovery effects of 2D nano blackcard nanoemulsion, and water were comprehensively evaluated. The results show that the final recovery factors of cores soaked in 2D nano blackcard (0.005 ωt%) and nanoemulsion (0.02 ωt%) or imbibed in water are 32.29%, 26.05%, and 7.19%, respectively. It can be found that 2D nano blackcard is the fluid with the best imbibition effect. In this work, a new type of 2D nano blackcard was proposed... [more]

The main focus of this research has been on examining the renewable energy sources (RESs) consumption with respect to green consumer values (GCVs). These GCVs have primarily been examined with regard to different products and services. The most significant strategy for strengthening everyone is social education. While GCVs are assumed to be nurtured through education, specific understanding about the long-term benefits of renewable energy for a sustainable life is measured with the belief that the greater the training and development the better shaped the society can be, which boosts morale and increases their energy reliance with RES, assessed by the respondents of Uttar Pradesh (UP), as the outcome of the research. The implications for the stakeholders are the long-term advantages of renewable energy for a sustainable existence, since a society may be better formed and its reliance on RESs for energy rises the more training and development it receives. The advantages are visible, tho... [more]

One viable option for meeting global energy demand is the creation of biofuels from plant species that demonstrate high biomass productivity and good energy characteristics. In this study, growth was evaluated using plant height (PH), the production of green (GB) and dry biomass (DB), and the energy quality of leaves, pods, and stems, considering apical and basal sections of maralfalfa plants at 28, 60, 90, and 140 days after applying a uniformity cut (AUC). The variables were analyzed with correlation tests and variance analyses (ANOVA) using a factorial array design; in addition, Tukey tests were performed. A steady increase in PH (72 to 239 cm) was found. The highest yield of stems was at 90 AUC (41,362 kg/ha) for GB and 140 days AUC (6331 kg/ha) for DB, and a high correlation was observed between PH and stem biomass production for both the GB (r = 0.91) and DB (r = 0.93). There was a strong correlation between higher heating value and DB from the apical stratum (r = 0.99) and the b... [more]

This research focused on the design of a distributed approach using consensus theory to find an optimal solution of the economic dispatch problem (EDP) by considering the quadratic cost function along with the valve-point effect of generators and renewable energy systems (RESs). A distributed consensus approach is presented for the optimal economic dispatch under a complex valve-point effect by accounting for solar energy in addition to conventional power plants. By employing the beta distribution function and communication topology between generators, a new optimality condition for the dispatch problem was formulated. A novel distributed updation law for generation by considering the communication between generators was provided to deal with the valve-point effect. The convergence of the proposed updation law was proved analytically using Lyapunov stability and graph theory. An algorithm for ensuring a distributed economic dispatch via conventional power plants, integrated with solar... [more]

Adsorption heat storage is the most feasible technology for heating decarbonization, which can store large quantities of waste and renewable heat for an exceptionally long time. However, utilizing adsorption heat storage in geographical locations with sub-zero ambient conditions is challenging. Therefore, this paper experimentally investigates the use of ethanol as a working fluid paired with silica gel for adsorption heat storage and utilizes sub-zero ambient as the heat source. The heat storage characteristics, heat charging/discharging cyclic performance, and energy conversion performance via exergy analysis were determined under realistic operating conditions and benchmarked against the widely investigated silica gel/water. Ethanol adsorbate was successfully utilized as a working fluid to employ the evaporators operating under sub-zero ambient conditions. Silica gel/ethanol showed the most significant net cyclic uptake, twice that of silica gel/water. However, the physical characte... [more]

As the top emitter of carbon dioxide worldwide, China faces a considerable challenge in reducing carbon emissions to combat global warming. Carbon emissions from coal consumption is the primary source of carbon dioxide emissions in China. The decomposition of the driving factors and the quantification of regions and industries needs further research. Thus, this paper decomposed five driving factors affecting carbon emissions from coal consumption in China, namely, carbon emission intensity, energy structure, energy intensity, economic output, and population scale, by constructing a Kaya-Logarithmic Mean Divisia Index (Kaya-LMDI) decomposition model with data on coal consumption in China from 1997 to 2019. It was revealed that the economic output and energy intensity effects are major drivers and inhibitors of carbon emissions from coal consumption in China, respectively. The contribution and impact of these driving factors on carbon emissions from coal consumption were analyzed for dif... [more]

The origin of the high content of wet gases in coalbed seams is very important geologically, especially in the Enhong syncline in China. The present study focuses on the role of the material that generates the hydrocarbons. The effect of the pore structure on the generation of wet gases has not been thoroughly examined. The present paper characterizes the coal pore structure in the “wet gas area” and “dry gas area”. The pore structures in the two areas are shown to have different features, which affect the distribution of the wet gases. With respect to the pore structure parameters, coals in the wet gas area have a greater total specific surface area and pore volume in micropores. The pore structure types also differ between the two areas: the pore structures in the dry gas areas are mainly of the parallel type and reverse S type, which is favorable for the migration and dissipation of coalbed gases. The pore structure in the wet gas area is relatively closed, with poor connectivity an... [more]

When evaluating the energy efficiency of buildings and implementing the necessary measures to increase energy efficiency levels, thermal technical characteristics are determined. For this purpose, in situ measurements of the thermal resistance of external enclosing structures were carried out. One of the methods most often used by researchers is the non-destructive method—the heat flow meter (HFM) method regulated by ISO 9869. In the case of surveying a building with a high level of thermal resistance, researchers are faced with low-density heat flux measurements, which is always a difficult task due to significant fluctuations and the influence of external factors on the measurement results. This is due to the fact that it is difficult to determine what is a useful signal and what is a consequence of the effects of non-stationarity and heat transfer conditions. The article provides an example of low-density heat flux measurements when determining the thermal resistance of a building a... [more]

This study aims to provide a review of the state-of-the-art literature regarding the impacts and contributions of corn ethanol on retail gasoline prices in the US. For this, a systematic literature review following PRISMA statement was carried out, seeking to answer four research questions: (1) What are the main characteristics of the literature regarding the impact and contributions of ethanol on US retail gasoline prices? (2) What are the main article clusters identified in the evaluated literature? (3) What was the numerical impact of the Volumetric Ethanol Excise Tax Credit/Renewable Fuel Standard (VEETC/RFS) mandate on the price of gasoline and what are the main methods used for calculation in the literature? (4) What are the main trends and possibly new research directions for this literature? As a result of the characterization of the sample, driving themes, such as energy policy, costs, price dynamics, trade and energy market, were identified. Furthermore, three main clusters w... [more]

Two di-ureasils incorporating oxyethylene segments with average molecular weights Y = 600 and 900 g mol−1, prepared by the sol-gel method, and doped with the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and lithium tetrafluoroborate (LiBF4) salt were prepared. The as-obtained films are translucent, flexible, and hydrophobic, and have a low level of nanoscale surface roughness. The ionic conductivity values exhibited by an optimized sample are 8.10 × 10−5 and 2.8 × 10−4 S cm−1 at room temperature and 55 °C, respectively. The main goal of the work was to employ the electrolytes in prototype electrochromic devices (ECDs) with the [glass/a-IZO/a-WO3/d-U(Y)LiBF4-[Bmim]Cl/c-NiO/a-IZO/glass], noted as ECD1 for Y = 600 and ECD2 for Y = 900, where a-WO3 and c-NiO stand for amorphous tungsten oxide and crystalline nickel oxide, respectively. At 555 nm the ECD1 device exhibited the highest coloration efficiency for coloring (CEin = −420.621 cm2·C−1), the highest optical density va... [more]

In addition to active power generation, photovoltaic inverters can be used to provide ancillary services to grids, including reactive power compensation. This paper proposes a metaheuristic approach based on particle swarm optimization for the allocation and sizing of photovoltaic inverters that perform the complementary functions of static synchronous compensator (PV-STATCOM) units. The objective of the aforementioned approach is to reduce the initial investment cost in the acquisition of PV-STATCOM units. The proposed methodology considers both the daily load curve and generation and is applied to a 33-bus test system. The methodology is validated based on an exhaustive search algorithm and tested over 1000 consecutive simulations for the same problem; consequently, the methodology produces low standard deviations and errors, indicating its robustness. The methodology demonstrates an improved grid voltage profile throughout the day when applied to the 33-bus test system. Furthermore,... [more]

The article discusses the results of experimental studies on the course of pyrolysis oil injection through the high-pressure injector of a direct-injection engine. The pyrolysis oil used for the tests was derived from waste plastics (mainly high-density polyethylene—HDPE). This oil was then distilled. The article also describes the production technology of this pyrolysis oil on a laboratory scale. It presents the results of the chemical composition of the raw pyrolysis oil and the oil after the distillation process using GC-MS analysis. Fuel injection tests were carried out for the distilled pyrolysis oil and a 91 RON gasoline in order to perform a comparative analysis with the tested pyrolysis oil. In this case, the research was focused on the injected spray cloud analysis. The essential tested parameter was the Sauter Mean Diameter (SMD) of fuel droplets measured at the injection pressure of 400 bar. The analysis showed that the oil after distillation contained a significant proporti... [more]

To characterize the hydraulic fracture network of a conglomerate reservoir, a slant core well was drilled aimed to obtain direct information regarding hydraulic fractures through slant core at the conglomerate hydraulic fracturing test site (CHFTS). Core fracture classification was the fundamental issue of the project. In this study, three grade classifications for core fractures were proposed. Comprehensive classification of core fractures was carried out using the analytic hierarchy process (AHP)−fuzzy comprehensive evaluation (FCE) method. Finally, the fracture classification results were validated against numerical simulation. The grade-1 fracture classification included hydraulic fractures, drilling-induced fractures and core cutting-induced fractures. A total of 214 hydraulic fractures were observed. For the grade-2 classification, the hydraulic fractures were divided into 47 tensile fractures and 167 shear fractures. For the grade-3 classification, the shear fractures were subdi... [more]

The emissions from direct injection (DI) diesel engines remain a serious setback from the viewpoint of environmental pollution, especially for those who have been persuaded to use biofuel as an alternative fuel. The main drawbacks of using biofuels and their mixtures in DI diesel engines are increased emissions and decreased brake thermal efficiency (BTE) compared to using neat diesel fuel. The current study analyses the biodiesel made from cashew nut shell liquid (CNSL) using a single-cylinder, direct-injection diesel engine to validate the engine’s performance and discharge characteristics. In addition to the improved CNSL and a twin-fuel engine that runs on hydrogen, ethanol was added to the fuel at rates of 5%, 10%, and 15%. The investigation was conducted using a single-cylinder direct injection diesel engine at steady-state settings, above the sustained engine speed (1500 RPM). Several performance parameters and pollutant emissions, such as hydrocarbons (HC), carbon monoxide (CO)... [more]