Decreasing production and rising prices of cars, especially those with electric drive, lead to longer use of cars with internal combustion engines. It can be assumed that in the future, more and more cars powered by such engines with high mileage and therefore high wear will be used. Engine wear leads to reduced efficiency and increased emissions. This paper analyzes the impact of wear of the piston−rings−cylinder system components on energy losses associated with gas leakage from the combustion chamber and friction of the rings against the cylinder liner in a car spark-ignition engine. A ring pack model was used for the analyses. The input data for the simulation were gained in measurements made on the engine test stand and measurements of the wear of the engine components used in the car. The energy losses associated with blow-by in an unworn engine ranged from 1.5% of the indicated work at high load to almost 5% at low load. In the engine after 300,000 km, these losses increased to... [more]

The radioactive gas radon is ubiquitous in the environment and is a major contributor to the human inhalation dose. It is the second leading cause of lung cancer after smoking. Radon concentrations are particularly high in the air of radon-hazardous facilities—uranium mines and radioactive waste repositories containing radium. To reduce the dose load on the staff, air in these premises should be continuously or periodically purified of radon. Carbon adsorbers can be successfully used for this purpose. The design of sorption systems requires information on both equilibrium and kinetic parameters of radon dynamic adsorption. The traditional way of obtaining such characteristics of the sorbent is to analyze the breakthrough curves. The present paper proposes a simple alternative method for determining parameters of dynamic radon adsorption (Henry’s constant and equilibrium adsorption layer thickness) from the results of a layer-by-layer gamma-spectrometric measurement of the sorbent. The... [more]

In the literature on the subject, it is argued that tax policy is one of the tools stimulating the transition toward sustainable economies. Public authorities can use two functions for this purpose: fiscal and non-fiscal functions. High emission rates and the rising rapid atmospheric changes that come with them are serious threats to the climate and sustainable development. Reducing greenhouse gas emissions is one of the goals towards which the world strives (including the EU), so as to keep a balance between people’s expectations, economic aspects, and the needs of the environment. Therefore, it is necessary to explain whether, along with other factors, environmental policy and its component “green taxes” can act as a factor in limiting greenhouse gas emissions. The purpose of this article is to seek an answer to the question of whether “green taxes” as an instrument of tax policy are a significant factor influencing climate change by contributing to reducing greenhouse gas emissions.... [more]

The introduction of the new round of electricity reform policies has made the electricity sales companies’ trading environment increasingly complex. In the medium- and long-term market and spot market, following the new policy-oriented optimization of trading decisions is the focus of electricity sales companies. The main objective of this study is to consider the impact of the latest policies of China’s current electricity reform on each subject of electricity trading and to propose a method for electricity sales companies to make optimal decisions on renewable energy source (RES) power and conventional energy source (CES) power mixed with power trading in the medium- and long-term and spot markets to improve the efficiency of electricity market trading, promoting the consumption of renewable energy and helping the synergistic development of the electricity market and the tradable green certificate (TGC) market. This paper first discusses the impact of the new electricity reform polic... [more]

Climate change and related national mitigation targets make the decarbonization of the power sector an urgent need. The power sector faces the challenge of considering the design and interaction between emission reduction policies, which can sometimes counteract each other. This study proposes a framework that can be used to quantitatively study the qualitative link between carbon pricing and capacity pricing. The framework is validated through a case study in Hokkaido, Japan, and used to further investigate the interaction between the two policies through a System Dynamics simulation model and scenario design. The results indicate that a carbon price would promote the introduction of wind power, as well as the reduction in fossil fuels, while the capacity price will mitigate the boom-and-bust investment cycle and stabilize electricity prices. However, when the two policy-based prices act on the power system simultaneously, the advantages will be offset by each other. The existence of... [more]

The aim of this work is to adapt the methods of optical Hilbert diagnostics for the visualization and study of inverse diffusion H2/O2 flame. The diagnostic complex is implemented on the basis of the IAB-451 device with modified optical filtering. Visualization of phase perturbations induced by the studied medium in a probing multiwave light field is performed via polychromatic Hilbert and Foucault-Hilbert transformations in combination with registration and RGB-per-pixel processing of the dynamic structure of the images. From solution to the inverse problem of Hilbert optics using a physically justified initial approximation of the problem under consideration, the temperature field of the flame is reconstructed and the value of the H2, H2O, O2 and N2 concentrations may be restored.

The article considers the main tendencies of development of alternative liquid fuels used in aviation, land transport, and for the needs of power generation sector. An overview of the main constraints to the development of alternative fuel technologies in these technical areas was carried out. The main groups of the most promising components and fuel compositions capable of effectively replacing conventional liquid fuels have been generalized. The basic criteria for evaluating alternative fuels are formulated. Environmental indicators of fuel combustion are of paramount importance for aviation. Rheological characteristics, calorific value, and environmental friendliness are critical for land transport engines. The effectiveness of alternative fuels for the power generation sector needs to be assessed in terms of such factors as economic, environmental, rheological, and energy to find an optimal balanced formulation. The list of potential components of alternative liquid fuels is extrem... [more]

The vessel speed reduction program (VSRP) was first introduced in the Port of Los Angeles in 2001 to improve air quality. In this study, an algorithm was developed to calculate ship emissions with a bottom-up approach based on ship activity using automatic identification system (AIS) data. The target vessel applied to the emission calculation was a vessel participating in Korea’s VSRP. Factors considered for the calculation of emissions were ship type, speed, gross tonnage, engine power, load, sulfur content of fuel, and fuel consumption rate by engine age. The algorithm is designed to calculate the reduction amount by VSRP by simultaneously calculating the emission amount of the actual speed and the emission amount of the cruise speed when not participating in VSRP. The emission results of ships that participated in the VSRP in 2020 revealed that their speed was reduced by 47% and carbon dioxide emissions by 71.9%. These results were verified through comparison with the fuel consumpti... [more]

Discussed in this study is a bidirectional power control technique for a three-phase grid connected inverter under different unbalanced grid conditions. Prior researchers have focused on either solving the unbalanced problem or controlling the power. However, this paper addresses both issues: solving the unbalanced problems of the point-of-common-coupling (PCC) voltages and grid currents, and reducing the large ripple in the real and reactive power while also applying a bidirectional power control under weak grid conditions. A phase-locked loop (PLL) is not required because a simpler PR controller was employed. A symmetrical components extraction method was used. Compared to previous symmetrical component techniques that used complicated transformations, this approach requires less computations. Since the unbalanced load issue has been resolved, other loads connected to the grid will not be impacted. MATLAB Simulink was used in simulation experiments, and a real-time interface platform... [more]

The aim of this work is to analyse the dependence of carbon dioxide (CO2) emissions on total energy consumption, the energy produced from renewable sources, the energy produced in nuclear power plants and the gross domestic product (GDP) in 22 European countries, over the period 1992−2019. The fully modified ordinary least squares model (FMOLS) and dynamic OLS (DOLS) were used to estimate the long-term cointegration relationship between the variables. First differenced (FD) general moments methods (GMM) were used in the estimation of short-run relationship dynamics. The results suggest that energy produced from renewable sources causes a reduction in CO2 emissions per capita. On the other hand, total energy consumption increases CO2 emissions in the long run. Although the mitigation effect of nuclear power was not found to be significant across the entire block of countries studied, a closer look at countries utilising nuclear energy reveals that nuclear energy positively affects the r... [more]

Chillers are widely used in commercial buildings for air conditioning, and their energy consumption is the main contribution to the building’s carbon emissions. Currently, the COPs of small- and medium-capacity screw chillers are still generally lower than 6.5, whereas large-capacity commercial centrifugal chillers have achieved an ultra-high energy-efficiency level of COP ≥ 7.0. To achieve an ultra-high energy efficiency of COP ≥ 6.5 in medium-capacity chillers, the authors developed a 200 RT screw chiller by adopting the technologies of two-stage compression and interstage vapor injection. The whole development process, including the design, simulation, analysis, and experiment, is presented in this paper. It was found that the two-stage compression technology could effectively boost the performance of the chiller’s compressor to a maximum volumetric and adiabatic efficiency of 99% and 80%, respectively. With the interstage vapor injection technology, the chiller’s cooling capacity a... [more]

This study characterises materials that belong to the group of refuse-derived fuels (RDF). This group of materials regarded as an alternative fuel is derived from industrial, municipal solid and commercial wastes. The aim of this study is to evaluate the quality of waste composition, demonstrate statistically different values and the energy efficiency of the fuel derived from waste. Data on incinerated waste were collected from two different sources. The basic physical and chemical parameters of waste include density and water content. The lower heating value (LHV) of waste, chlorine concentration and ash content of two groups of incinerated waste were also evaluated and compared for a given period of time (one year, with monthly breakdown). Statistical analysis indicated the differences in the combustion of waste groups, visualized by box plots and other diagrams to show the distribution of the results. An analysis of exhaust gas parameters was carried out, both in terms of chemical c... [more]

Green ammonia has potential as a zero-emissions energy vector in applications such as energy storage, transmission and distribution, and zero-emissions transportation. Renewable energy such as offshore wind energy has been proposed to power its production. This paper designed and analyzed an on-land small-scale power-to-ammonia (P2A) production system with a target nominal output of 15 tonnes of ammonia per day, which will use an 8 MW offshore turbine system off the coast of Nova Scotia, Canada as the main power source. The P2A system consists of a reverse osmosis system, a proton exchange membrane (PEM) electrolyser, a hydrogen storage tank, a nitrogen generator, a set of compressors and heat exchangers, an autothermal Haber-Bosch reactor, and an ammonia storage tank. The system uses an electrical grid as a back-up for when the wind energy is insufficient as the process assumes a steady state. Two scenarios were analyzed with Scenario 1 producing a steady state of 15 tonnes of ammonia... [more]

To improve the energy density of lithium-ion battery packs, lithium-ion batteries are gradually advancing towards large-size structures, which has become one of the dominant development trends in the battery industry. With large-size blade lithium-ion batteries as the research object, this paper develops a high-precision electro-thermal coupling model based on the relevant parameters obtained through basic performance experiments, explores the mechanism of battery inhomogeneity from a simulation perspective, and further proposes a design management method. First of all, the optimal intervals of capacity and temperature, as well as the characteristics of the inhomogeneity distribution for large-size cells, are determined by essential performance and inhomogeneity tests; subsequently, the electrochemical and thermal characteristics of the large-size battery are described precisely through a 3D thermoelectric coupling mechanism model, and the inhomogeneity of the temperature distribution... [more]

Long-haul heavy-duty vehicles, including trucks and coaches, contribute to a substantial portion of the modern-day European carbon footprint and pose a major challenge in emissions reduction due to their energy-intensive usage. Depending on the hydrogen fuel source, the use of fuel cell electric vehicles (FCEV) for long-haul applications has shown significant potential in reducing road freight CO2 emissions until the possible maturity of future long-distance battery-electric mobility. Fuel cell heavy-duty (HD) propulsion presents some specific characteristics, advantages and operating constraints, along with the notable possibility of gains in powertrain efficiency and usability through improved system design and intelligent onboard energy and thermal management. This paper provides an overview of the FCEV powertrain topology suited for long-haul HD applications, their operating limitations, cooling requirements, waste heat recovery techniques, state-of-the-art in powertrain control, e... [more]

Quality in healthcare service is essential in giving rural dwellers a good standard of living. It has been established that many rural locations in Sub-Saharan Africa away from the grid connection have difficulty accessing electricity. The inaccessibility of reliable energy and essential medical equipment was the leading barrier to improved healthcare delivery in these rural locations. The deficiency of basic medical equipment to power essential services due to limited or unreliable electricity access has reduced rural healthcare workers’ care capabilities, resulting in higher mortality rates. This paper, therefore, reviews the existing energy solutions for rural healthcare facilities, thereby analysing different approaches and the geographical energy mix and ascertaining the effectiveness of various techniques and energy mix as solutions to effective healthcare delivery in healthcare centres. Hybrid Renewable Energy Sources (HRES) microsystems, like microgrids incorporated with solar... [more]

Multi-terminal HVDC grids facilitate the integration of various renewable resources from distant locations; in addition, they enhance the reliability and stability of the grid. Protection is one of the major obstacles in realizing reliable and secure multi-terminal HVDC grids. This paper presents a comprehensive review of the existing protection schemes for multi-terminal HVDC grids. First, DC fault current stages are demonstrated; in addition, fault analysis studies and the existing fault current calculation methods are reviewed. Then, HVDC grid protection requirements including multi-vendor interoperability conditions are extensively discussed. Furthermore, primary protection algorithms are classified into single- and double-ended schemes, and a detailed comparison between each category is presented such that the distinctive algorithms from each group are highlighted. Moreover, the recent DC reclosing schemes are reviewed highlighting their role in enhancing grid stability and ensuri... [more]

A dry, low-NOx (DLN) combustor for a heavy-duty gas turbine using lean premixed technology was studied. A high-fidelity test model was built for the experimental study using particle image velocimetry (PIV). The non-reacting flow in the DLN combustion chamber was investigated experimentally and numerically. The numerical results are in good agreement with the experimental data. The results show that recirculation zones were formed downstream of each swirl nozzle and that the flow pattern in each section was self-similar under different working conditions. For two adjacent swirl nozzles with opposite swirling directions, the entrainment phenomenon was present between their two flows. The two flows gradually mixed with each other and obtained a higher speed. If the two adjacent swirl nozzles had the same swirling direction, then the mixing of the two flows out of the nozzles was not present, resulting in two separate downstream recirculation zones. The interaction of swirling flows out o... [more]

The quantitative identification of water sources is an important prerequisite for objectively evaluating the degree of aquifer interference and predicting the production potential of coalbed methane (CBM) wells. However, this issue has not been solved yet, and water sources are far from being completely understood. Stable water isotopes are important carriers of water source information, which can be used to identify the water sources for CBM wells. Taking the Zhijin block in the Western Guizhou Province as an example, the produced water samples were collected from CBM wells. The relationships between the stable isotopic compositions of the produced water samples and the production data were quantitatively analyzed. The following main conclusions were obtained. (1) The δD and δ18O values of the produced water samples were between −73.37‱ and −27.56‱ (average −56.30‱) and between −11.04‱ and −5.93‱ (average −9.23‱), respectively. The water samples have D-drift characteristics, showing t... [more]

Cooking with electricity (eCook) in low-and-middle-income developing countries is still an expensive option compared to using conventional fuels such as charcoal and firewood, so there is a need to identify solutions to make it affordable for all in line with the targets of SDG7. The initial aim of this paper is to understand and provide a comparative analysis of the cooking energy costs through a range of contextualized cooking scenarios—when cooking either with conventional fuels (e.g., charcoal, firewood) or with eCook appliances (e.g., electric pressure cookers (EPC) or hotplates), that are connected to and supplied from an integrated or portable battery (eCook battery). The cooking cost for the eCook cooking scenarios is assessed with and without fuel stacking where a degree of eCook exists alongside other conventional fuels. These studies offer a more realistic concept of the cooking practice to characterize the best fit for cooking scenarios and the main factors required to clos... [more]

The low-strain integrity testing of large-diameter piles has attracted more and more attention because of its wide application in offshore engineering, such as for wind turbines, etc. Body and Rayleigh waves generate on the top surface of large-diameter piles after the excitation load. The multi-reflections of these waves from the pile side result in the obvious three-dimensional effect at the pile top. Therefore, one-dimensional wave theory is no longer suitable for interpreting the wave propagation in the pile body under vertical excitation. In this paper, based on the “pile in pile” conception, both the pile and soil were simulated using a three-dimensional continuum model, considering the vertical displacement, to investigate the influence of the three-dimensional effect of the pile-soil system on the vertical dynamic response of large-diameter piles in low-strain integrity testing. The axisymmetric solution to the three-dimensional pile-soil system was obtained, and the rationalit... [more]

Studies of storage and production of hydrogen, which is an alternative to fossil fuels, have been intensified. Hydrogen production from metal borohydrides via catalyst is very attractive because of its advantages, such as controlled production, high hydrogen content, nontoxicity, etc. In this study, the catalytic performances of nanoporous nickel−chromium alloy and nickel−vanadium alloy catalysts prepared with magnetron sputtering in hydrolysis of potassium borohydride, which is a hydrogen storage material, were investigated. Parameters that affected the hydrolysis reaction rate, such as the temperature, the amount of catalyst, and the volume of 0.5 M HCl solution were investigated using response surface methodology. In addition, the prepared catalysts were characterized with XRD and FE-SEM analysis, and the remaining solutions after the reactions were characterized with FE-SEM/EDS analysis. Using response surface methodology, optimum conditions for the maximum hydrogen production rate... [more]

This work aims to assess the impacts of climate change on photovoltaic (PV) electricity in two Italian cities, with different latitudes and Köppen−Geiger climate classifications. This was undertaken using the recent EURO-CORDEX set of high-resolution climate projections and PV power generation models, implemented on TRNSYS software. Data for two variables (surface air temperature and solar radiation) were analysed over a long period from 1971 to 2100. For future periods, two of the Representative Concentration Pathway scenarios (RCP4.5 and RCP8.5) used in the Intergovernmental Panel on Climate Change Fifth Assessment Report were considered. In both RCP scenarios and both locations, it is estimated that the yearly PV energy produced in the future period will not undergo significant variations on average given that the rate of decrease is foreseen almost constant; instead, a slight reduction in the PV energy was detected in the past period. It can be concluded that the PV market in Italy... [more]

Calcite cement is a common type of cementation in tight sandstone reservoirs of the Upper Triassic Yanchang Formation Chang 8 Member in the Zhijing-Ansai area of the Ordos Basin, which has significant influence on reservoir densification and heterogeneity. Calcite cements affect the quality of the reservoir conspicuously. The characteristics and origins of calcite were investigated using a series of approaches from the perspective of petrography and geochemistry, including thin section observation and identification, cathode luminescence, scanning electron microscopy, AMICS analysis, LA-ICP-MS elements analysis, and carbon and oxygen isotopes analysis. The results of all analytical tests indicated that calcite cements can be divided into two types according to their occurrence and origins. Type-I calcite cements mainly occur in sandstone reservoirs near the sandstone−mudstone interface or the sandstone layers adjacent to mudstone. Generally, there is no chlorite coating around them, an... [more]

The performance of an enhanced vapor-injection heat-pump drying system was designed and theoretically studied in cold areas. According to the simulation findings, the ideal vapor-injection charge of the system ranges from 12.3 to 13.9%, and its ideal intermediate pressure is between 1.278 and 1.498 MPa when the evaporation temperature is above 0 °C. The ideal vapor-injection charge of the system ranges from 13 to 20%, and its optimal intermediate pressure ranges from 1.078 to 1.278 MPa when the evaporation temperature is −15−0 °C. The ideal vapor-injection charge of the system ranges from 20 to 24%, and the intermediate pressure ranges from 0.898 to 1.078 MPa when the evaporation temperature is below −15 °C. The heat and humidity exhausted air source heat-pump drying (HHE−ASHPD) system has higher dehumidification efficiency than the closed heat-pump drying (CHPD) system under the same air temperature, humidity, and volume parameters.