Geothermal power plants have become the main application that utilizes geothermal energy. The utilization of deep geothermal energy adheres great importance to the soil condition. One of the biggest challenges faced by geothermal power plant designers is to reduce the risk of soil exploration. To solve this problem, forecasting by modeling has proven to be an important tool to address the problem. In this research, a geo-model was established by modeling three geological layers with different hydraulic and thermal properties to solve the above dilemma. The layers, elevation, and fault zones were simulated using interpolation functions from an artificial dataset. The coupled porous media flow and heat transfer problem using Darcy’s law, as well as heat transfer in porous media interfaces, were studied. The evolution of the flow field, hydrothermal performance, and temperature gradient were also analyzed for a period of 10 years. The results showed the recoverable thermal energy area gra... [more]

Two years of high-resolution simulations conducted with the Weather Research and Forecasting (WRF) model are used to characterize the frequency, intensity and height of low-level jets (LLJ) over the U.S. Atlantic coastal zone. Meteorological conditions and the occurrence and characteristics of LLJs are described for (i) the centroids of thirteen of the sixteen active offshore wind energy lease areas off the U.S. east coast and (ii) along two transects extending east from the U.S. coastline across the northern lease areas (LA). Flow close to the nominal hub-height of wind turbines is predominantly northwesterly and southwesterly and exhibits pronounced seasonality, with highest wind speeds in November, and lowest wind speeds in June. LLJs diagnosed using vertical profiles of modeled wind speeds from approximately 20 to 530 m above sea level exhibit highest frequency in LA south of Massachusetts, where LLJs are identified in up to 12% of hours in June. LLJs are considerably less frequent... [more]

Automation and electrification are changing vehicles and mobility. Whereas electrification is mainly changing the powertrain, automation enables the rethinking of the vehicle and its applications. The actual driving range is an important requirement for the design of automated and electric vehicles, especially if they are part of a fleet. To size the battery accordingly, not only the consumption of the powertrain has to be estimated, but also that of the auxiliary users. Heating Ventilation and Air Conditioning (HVAC) is one of the biggest auxiliary consumers. Thus, a variable HVAC model for vehicles with electric powertrain was developed to estimate the consumption depending on vehicle size and weather scenario. After integrating the model into a tool for autonomous and electric vehicle concept development, various vehicle concepts were simulated in different weather scenarios and driving cycles with the HVAC consumption considered for battery sizing. The results indicate that the bat... [more]

The thermal efficiency of an efficient gasoline engine is only about 40% and it will produce a large number of harmful products. Curbing harmful emissions and enhancing thermal efficiency have always been the goals pursued and emission regulations are also being tightened gradually. As one of the main consumers of fossil fuels, automobile engines must further reduce fuel consumption and emissions to comply with the concept of low-carbon development, which will also help them compete with electric vehicles. Homogeneous charge compression ignition (HCCI) combustion combined with variable valve actuation (VVA) technology is one of the important ways to improve engine emissions and economy. HCCI combustion based on VVA can only be realized at small and medium loads. The actual application on the entire vehicle needs to be combined with spark ignition (SI) combustion to achieve full working condition coverage. Therefore, HCCI combustion needs fast valve response characteristics; however, th... [more]

Energy transition is a multi-dimensional process of developing sustainable economies by seeking renewable energy sources, saving energy, and improving energy efficiency. This process follows the rules of sustainable development. The article presents an analysis of energy transition in the Baltic Sea Region (BSR) enjoying long-term and intensive territorial cooperation. The region embraces 11 countries diversified in terms of their economic development level and the use of renewable energy sources. The article strives to answer the question of whether territorial cooperation contributes to BSR energy transition, and if so, in what way. Another goal is to identify the transition drivers that arise from the Baltic Sea Region’s unique characteristics. The authors applied the system analysis methodology. The performed literature studies allowed the researchers to identify the attributes of energy transition. Empirical research relied on secondary sources, including the European Union (EU) s... [more]

The combination/integration of renewable energy and storage systems appears to have significant potential, achieving high-energy results with lower costs and emissions. One way to cover the thermal needs of a building is through solar energy and its seasonal storage in the ground. The SMARTEP project aims to create an experimental area that provides for the construction of a road solar thermal collector directly connected to a seasonal low-temperature geothermal storage with vertical boreholes. The storage can be connected to a ground-to-water heat pump for building acclimatization. This system will meet the requirements of visual impact and reduction of the occupied area. Nevertheless, several constraints related to the radiative properties of the surfaces and the lack of proper thermal insulation have to be addressed. The project includes the study of several configurations and suitable materials, the set-up of a dynamic simulation model and the construction of a small-scale road the... [more]

Australia is one of the leading countries in energy transition, and its largest power system is intended to securely operate with up to 75% of variable renewable generation by 2025. High-inertia synchronous condensers, battery energy storage systems, and grid-forming converters are some of the technologies supporting this transformation while facilitating the secure operation of the grid. Synchronous condensers have enabled 2500 MW of solar and wind generation in the state of South Australia, reaching minimum operational demands of ≈100 MW. Grid-scale battery energy storage systems have demonstrated not only market benefits by cutting costs to consumers but also essential grid services during contingencies. Fast frequency response, synthetic inertia, and high fault currents are some of the grid-supporting capabilities provided by new developments that strengthen the grid while facilitating the integration of new renewable energy hubs. This manuscript provides a comprehensive overview,... [more]

Water is essential for food security, industrial output, ecological sustainability, and a country’s socioeconomic progress. Water scarcity and environmental concerns have increased globally in recent years as a result of the ever-increasing population, rapid industrialization and urbanization, and poor water resource management. Even though there are sufficient water resources, their uneven circulation leads to shortages and the requirement for portable fresh water. More than two billion people live in water-stressed areas. Hence, the present study covers all of the research based on water extraction from atmospheric air, including theoretical and practical (different experimental methods) research. A comparison between different results is made. The calculated efficiency of the systems used to extract water from atmospheric air by simulating the governing equations is discussed. The effects of different limitations, which affect and enhance the collectors’ efficiency, are studied. Thi... [more]

In this study, a bidirectional CL3C full-bridge resonant converter was developed using a bidirectional active bridge converter as the main framework to improve conventional LLC resonant converters. A resonant inductor and resonant capacitor were installed at the secondary side of the developed resonant converter. The bidirectional operation of this converter enables zero-voltage switching at the supply-side power switch and zero-current switching at the load side. The aforementioned phenomena enhance the overall circuit efficiency and enable the resonant tank voltage to be increased in the reverse mode, which cannot be achieved with conventional bidirectional LLC resonant converters. The electrical equipment isolation function provided by a transformer made electricity usage safer, and digital control technology was adopted to control electrical energy conversion and simulate bidirectional energy conversion. Specifically, the experiment and simulation emulated how the developed convert... [more]

The selection of effective surfactants potentially can mobilize oil up to 50% of residuals in mature carbonate oilfields. Surfactants’ screening for such oilfields usually is complicated by the high salinity of water, high lipophilicity of the rock surface, and the heterogeneous structure. A consideration of features of the oilfield properties, as well as separate production zones, can increase the deep insight of surfactants’ influence and increase the effectiveness of surfactant flooding. This article is devoted to the screening of surfactants for two production zones (Bashkirian and Vereian) of the Ivinskoe carbonate oilfield with high water salinity and heterogeneity. The standard core study of both production zones revealed no significant differences in permeability and porosity. On the other hand, an X-ray study of core samples showed differences in their structure and the presence of microporosity in the Bashkirian stage. The effectiveness of four different types of surfactants... [more]

The way in which rescue actions are carried out in a hard coal mine is conditioned by a number of factors, including the type, scale, and location of the hazard; location of employees at the danger and level of their endangerment; and the ventilation system used in the impacted area. In this article, the importance and necessity to take into account a human factor, specifically the propensity for risky behavior, alongside the selection of rescuers for rescue action is pointed out. As an introduction to the key research studies presented in this article, main ventilation systems used in hard coal mines are described and three real cases of natural hazard occurrences in hard coal mines are discussed. An analysis of these events has shown that the degree of difficulty of a rescue action depends, among other aspects, on the ventilation system applied. Next, a study covering a synthetic assessment of 25 mining rescuers taking into account the ‘risky behavior’ parameter is presented. The res... [more]

Azerbaijan has a well-developed hydrocarbon industry backed with abundant domestic resources. Oil and gas have played a crucial role in the economic revival of the country since independence was regained back in 1991. The legal foundation of the transition to carbon-zero energy generation was laid in the 1990s with a number of acts mentioning the importance of the shift. The government has an ambitious plan to improve the situation, though an action plan with targeted renewables share in production and consumption is still to be prepared. This study, based on systematic review methodology for qualitative research, analyzes the potential of renewables in Azerbaijan with a focus on solar and wind power, discusses the deficiencies hindering the development of the renewables industry, and develops recommendations on applicable actions to improve the situation in this regard. It also includes legislative acts of the Republic concerning renewable energy. The main objective of the study is to... [more]

Thermodynamic performance of three conceptual systems for biomass-derived olefin production with electricity cogeneration was studied and compared via exergy analysis at the levels of system, subsystem and operation unit. The base case was composed of the subsystems of gasification, raw fuel gas adjustment, methanol/light olefin synthesis and steam & power generation, etc. The power case and fuel case were designed as the combustion of a fraction of gasification gas to increase power generation and the recycle of a fraction of synthesis tail gas to increase olefin production, respectively. It was found that the subsystems of gasification and steam & power generation contribute ca. 80% of overall exergy destruction for each case, of which gasifier and combustor are the main exergy destruction sources, due to the corresponding chemical exergy degrading of biomass and fuel gas. The low efficiency of 33.1% for the power case could be attributed to the significant irreversibility of the com... [more]

Multi-tube multi-fin heat exchangers are extensively used in various industries. In the current work, detailed experimental investigations were carried out to establish the flow/heat transfer characteristics in three distinct heat exchanger geometries. A novel perforated plain fin design was developed, and its performance was evaluated against standard plain and louvred fins designs. Experimental setups were designed, and the tests were carefully carried out which enabled quantification of the heat transfer and pressure drop characteristics. In the experiments the average velocity of air was varied in the range of 0.7 m/s to 4 m/s corresponding to Reynolds numbers of 600 to 2650. The water side flow rates in the tubes were kept at 0.12, 0.18, 0.24, 0.3, and 0.36 m3/h corresponding to Reynolds numbers between 6000 and 30,000. It was found that the louvred fins produced the highest heat transfer rate due to the availability of higher surface area, but it also produced the highest pressur... [more]

To reduce the greenhouse effect, it is important to reduce not only carbon dioxide but also methane emissions. Methane gas can be not only a fossil fuel (natural gas) but also a renewable energy source when it is extracted from biomass. After biogas has been purified, its properties become closer to those of natural gas or methane. Natural gas is an alternative energy source that can be used for spark-ignition engines, but its physicochemical properties are different from those of gasoline, and the spark-ignition engine control parameters need to be adjusted. This article presents the results of a study that considers a spark-ignition engine operating at different speeds (2000 rpm, 2500 rpm, and 3000 rpm) and the regulation of the timing of intake valve closure when the throttle is partially open (15%), allowing the engine to maintain the stoichiometric air−fuel mixture and constant spark timing. Studies have shown a reduction in engine break torque when petrol was replaced by natural... [more]

In order to gain a comprehensive view of electric vehicles (EVs) technologies and understand the emphasis of current research, this study evaluated the most relevant themes related to EVs through a bibliometric analysis using the keyword “electric vehicle” as the input. The Web of ScienceTM (WoS) database was used because it is considered ideal for bibliometric analysis. The VOSviewer software was adopted as a bibliometric analysis tool to visualize the networks of authors, countries, journals and keywords. The analysis carried out on 9 November 2021 retrieved a total of 29,304 documents in the period 2000 to 2021. The results show that in the last nine years the number of publications about EVs has grown significantly. The China is the leading nation in the field of EV research, contributing the largest number of publications in the world, with the main authors and research institutions involved. The journal Energies stands out as the main publishing periodical. Keyword analysis showe... [more]

This paper examines the exergy efficiency and exergy destruction rate of the R744/R404A cascade refrigeration system (CRS) using an internal heat exchanger in supermarkets according to various conditions affecting the system. A refrigerant of a low-temperature cycle uses R744 and a refrigerant of a high-temperature cycle in the CRS uses R404A. Experiments were conducted by changing various conditions on the high- and low-temperature side, and exergy analysis was performed accordingly. The main results are summarized as follows: (1) the lower the total exergy destruction rate of the CRS, the higher the exergy efficiency of the system, and accordingly the coefficient of performance (COP) of the system is also improved. (2) In the CRS, since the optimum cascade evaporation temperature exists (about −16 °C), it can be said that the limit point, that is, the cascade evaporation temperature with the maximum COP of the system, is the optimum point at about −16 °C. Therefore, at this optimum p... [more]

In this study, we investigated the applicability of an automobile shredder residue (ASR) as an energy and recycling resource. First, ASR gasification was conducted in a fixed-bed reactor (throughput = 1 kg/h) at different temperatures (800, 1000, and 1200 °C) and an equivalence ratio of 0.1−0.5. Clay bricks were prepared with the solid residue obtained from the gasification process to address the issue of solid-residue production in pyrolysis. The syngas (H2 + CO) from ASR gasification had maximum and minimum yields of approximately 86 and 40 vol.%, respectively. Furthermore, the yield of syngas increased with the temperature and equivalence ratio (ER); therefore, the optimum conditions for the ASR gasification were determined to be a temperature of 1200 °C and an ER of 0.5. In addition, solid residues, such as char and ash, began to melt due to thermal heating in the range of 1300−1400 °C and were converted into melting slag, which was subsequently used to manufacture clay bricks. The... [more]

An effective way to enhance the heat transfer in mini and micro electronic devices is to use different shapes of micro-channels containing vortex generators (VGs). This attracts researchers due to the reduced volume of the electronic micro-chips and increase in the heat generated from the devices. Another way to enhance the heat transfer is using nanofluids, which are considered to have great potential for heat transfer enhancement and are highly suited to application in practical heat transfer processes. Recently, several important studies have been carried out to understand and explain the causes of the enhancement or control of heat transfer using nanofluids. The main aim upon which the present work is based is to give a comprehensive review on the research progress on the heat transfer and fluid flow characteristics of nanofluids for both single- and two- phase models in different types of micro-channels. Both experimental and numerical studies have been reviewed for traditional an... [more]

Pollutant emissions have been a topic of interest in the last decades. Not only environmentalists but also governments are taking rapid action to reduce emissions. As one of the main contributors, the transport sector is being subjected to strict scrutiny to ensure it complies with the short and long-term regulations. The measures imposed by governments clearly involve all the stakeholders in the logistics sector, from road authorities and logistic operators to truck manufacturers. The improvement of traffic conditions is one of the perspectives in which the reduction of emissions is being addressed. Optimization of traffic flow, avoidance of unnecessary stops, control of the cruise speed, and coordination of trips in an energy-efficient way are necessary steps to remain compliant with the upcoming regulations. In this study, we have estimated the CO2 and NOx emissions in heavy-duty vehicles while traversing signalized intersections, and we examined the differences between various beha... [more]

This paper comprehensively reviews the current status of multidisciplinary technologies in electric vehicles. Because the electric vehicle market will expand dramatically in the coming few years, research accomplishments in power electronics technology for electric vehicles will be highly attractive. Challenges in power electronics technology for driving electric vehicles, charging batteries, and circuit topologies are being explored. This paper aims primarily to address the practical issues of the future electric vehicles and help researchers obtain an overview of the latest techniques in electric vehicles, focusing on power electronics-based solutions for both current and future electric vehicle technologies. In this work, different medium-and high-voltage DC-AC inverter topologies are investigated and compared in terms of power losses and component requirements. Recent research on electric vehicle power converters is also discussed, with highlighting on soft-switching and multilevel... [more]

Oil shales are developed in the Shale Member of the Middle Jurassic Shimengou Formation in the Qaidam Basin, China. The oil shales can be classified into three quality groups (low-, medium-, and high-quality oil shales) through a comprehensive analysis protocol that includes Rock-Eval pyrolysis, total organic carbon (TOC) content, proximate analysis, gas chromatography-mass spectrometry (GC-MS), X-ray diffraction (XRD), major and trace element analyses, and maceral analysis. The low-quality oil shales mainly contain type II1 kerogen, the medium-quality oil shales mainly contain type I-II1 kerogen, and the high-quality oil shales mainly contain type I kerogen. All are immature to early thermally mature. The oil yield of the oil shales is directly related to their quality and are positively correlated with TOC content and calorific value. All studied samples were deposited under anaerobic conditions but in different paleoenvironments. The low-quality oil shales were mainly deposited in f... [more]

In this paper, a DC-DC converter with an innovative topology for automotive applications is proposed. The goal of the presented power converter is the electrical storage system management of an electric vehicle (EV). The presented converter is specifically compliant with a 400 V battery, which represents the high-voltage primary source of the system. This topology is also able to act as a bidirectional power converter, so that in this case, the output section is an active stage, which is able to provide power as, for example, in the case of a low-voltage battery or a supercapacitor. The proposed topology can behave either in step-down or in step-up mode, presenting in both cases a high gain between the input and output voltage. Simulation results concerning the proposed converter, demonstrating the early feasibility of the system, were obtained in a PowerSIM environment and are described in this paper.

Carbon capture and storage (CCS) is a key strategy to reduce carbon dioxide (CO2) emissions from industrial point sources. Gas absorption into aqueous amine solutions is an immediate technology for carbon capture that has been tested in many demonstration plants. One concern of using the amine-based carbon capture process is the environmental impacts and health risk caused by emissions of gaseous amines from the process to the atmosphere. This work applied the knowledge of air dispersion modelling to map out the atmospheric dispersion and resulting ground surface level concentration of gaseous amine, namely Monoethanolamine (MEA), from a coal-fired power plant (with a carbon capture unit) and in surrounding areas, in case of an accidental leaking of amine from the CCS system to the atmosphere. The chosen study area was centered on a coal-fired power plant in the province of Saskatchewan, Canada. The Environmental Protection (EPA) approved air pollution model (CALPUFF), together with me... [more]

Occupant behaviour plays a significant role in shaping the dynamics of energy consumption in buildings, but the complex nature of occupant behaviour has hindered a deeper understanding of its influence. A meta-analysis was conducted on 65 published studies that used data-driven quantitative assessments to assess energy-related occupant behaviour using the Knowledge Discovery and Data Mining (KDD) framework. Hierarchical clustering was utilised to categorise different modelling techniques based on the intended outcomes of the model and the types of parameters used in various models. This study will assist researchers in selecting the most appropriate parameters and methods under various data constraints and research questions. The research revealed two distinct model categories being used to study occupant behaviour-driven energy consumption, namely (i) occupancy status models and (ii) energy-related behaviour models. Multiple studies have identified limitations on data collection and p... [more]