Biosolids have been traditionally used as a beneficial resource in the agricultural industry. However, contaminants of emerging concern (CECs) threaten their reuse due to concerns of toxicity, bioaccumulation, and increased regulations on acceptable CEC concentrations in biosolids. The thermal treatment of biosolids has the potential to destroy/mineralize these contaminants as well as transform the biosolids into valuable biochar. However, the thermal processing of biosolids is highly energy intensive due to the energy costs associated with drying biosolids to the required moisture content for thermal processing. This article performs a brief review of the drying of biosolids from a physical and theoretical viewpoint. It also provides an overview of pyrolysis and gasification. It explains the impact that moisture can have on both the degradation of CECs and the products that can be obtained through the thermal treatment of biosolids. Additionally, model-based, lab-based, and pilot-scal... [more]

Big cities affected by intense mobility, traffic and pollution are adopting electrification-based solutions for the reduction of the CO2 emissions of combustion engines. An interesting field in which the transition toward electrification can achieve important benefits is the area of instant deliveries. Instant deliveries deal with the mobility related to commercial trades between suppliers and customers. In this respect, optimal solutions can be considered during route planning based on the minimization of several metrics, such as distance, energy and road slope, among others. To this end, this paper presents an optimal solution to the instant deliveries problem in which the result is the optimal route, in the city under study, that minimizes energy consumption based on road slope and total distance traveled, and that gives higher priority to routes that include cycling infrastructure that the city can provide. The paper uses electric bikes since they are easily transportable and are h... [more]

Recent motivation to cut greenhouse gas emissions to combat climate change has led to increasing transportation electrification. However, electric vehicle proliferation comes with a number of challenges such as battery capacities and the range anxiety of electric vehicles. In this paper, a review of the main components that affect electric vehicle adoption, which are charging infrastructure and energy resources, is presented. We discuss the categories of electric vehicle charging infrastructure, based on the location-of-charge and the charging technology. In addition, a review of the energy resources required for electric vehicles is also presented. The key features of these batteries are also discussed.

Wind turbine blades are one of the largest parts of wind power systems. It is a handicap that these large parts of numerous wind turbines will become scrap in the near future. To prevent this handicap, newly produced blades should be recyclable. In this study, a turbine blade, known as the new generation of turbine blade, was manufactured with reinforced carbon beams and recycled, low-density polyethylene materials. The manufacturing addressed in this study reveals two novelties: (1) it produces a heterogeneous turbine blade; and (2) it produces a recyclable blade. In addition, this study also covers mechanical tests using a digital image correlation (DIC) system and modeling investigations of the new generation blade. For the mechanical tests, displacement and strain data of both new generation and conventional commercial blades were measured by the DIC method. Instead of dealing with the modeling difficulty of the new generation blade’s heterogeneity we modeled the blade structural s... [more]

A new method for measuring membrane degradation in polymer electrolyte fuel cells (PEFCs) is proposed. The method is based on the detection of fluoride ions in effluent water from the cathode- and anode outlet of the PEFC using photometry (PM). The fluoride emission rate (FER) is an indicator of the membrane’s state of health (SoH) and can be used to measure the chemical membrane degradation. Commercial catalyst-coated membranes (CCMs) have been tested at 80 °C and 90 °C at 30% relative humidity (RH) to investigate the reliability of the developed method for fuel cell effluent samples. To verify the measurement, a mean-difference plot was created by measuring the same data with a fluorine selective electrode. The average difference was at ±0.13 nmol h−1 cm−2, which indicates good agreement between the two methods. These new findings imply that PM is a promising method for quick and simple assessment of membrane degradation in PEM technology.

The only strategy for reducing fossil fuel-based energy sources is to increase the use of sustainable ones. Among renewable energy sources, solar energy can significantly contribute to a sustainable energy future, but its discontinuous nature requires a large storage capacity. Due to its ability to be produced from primary energy sources and transformed, without greenhouse gas emissions, into mechanical, thermal, and electrical energy, emitting only water as a by-product, hydrogen is an effective carrier and means of energy storage. Technologies for hydrogen production from methane, methanol, hydrocarbons, and water electrolysis using non-renewable electrical power generate CO2. Conversely, employing photoelectrochemistry to harvest hydrogen is a sustainable technique for sunlight-direct energy storage. Research on photoelectrolysis is addressed to materials, prototypes, and simulation studies. From the latter point of view, models have mainly been implemented for aqueous-electrolyte c... [more]

This review study examines flow boiling heat transfer in micro-fin tubes using mixed and pure refrigerants with zero ozone-depleting potential (ODP) and minimal global warming potential (GWP). This investigation focuses on the extraordinary relationship between heat transfer coefficients (HTCs) and vapor quality. Since the introduction of micro-fin heat exchanger tubes over 30 years ago, refrigerant-based cooling has improved significantly. Air conditioning and refrigeration companies are replacing widely used refrigerants, with substantial global warming impacts. When space, weight, or efficiency are limited, micro-fin heat exchangers with improved dependability are preferred. This review article discusses flow boiling concepts. The researchers used several refrigerants under different testing conditions and with varying micro-fin tube parameters. Micro-fin tubes are promising for improved heat transfer techniques. This tube increases the heat transfer area, fluid disturbance, flow sp... [more]

Bioethanol and dimetyl carbonate (DMC) are considered alternative fuels and additives to the synthesis compounds used now, since bioethanol is a biofuel and dimethyl carbonate (DMC) is non-toxic, biodegradable and can be produced in a cleaner way. In this study, the effect of adding dimethyl carbonate (DMC) and ethanol to gasoline on the volatility was investigated. The volatility was the main goal of this research but also, the effect on the antiknock properties was studied. Mixtures of gasoline with DMC or with bioethanol were prepared in different proportions of additive: 3%, 6% and 9% v/v. Additionally, mixtures with 3% v/v ethanol plus 3% or 6% v/v DMC, and3% DMC plus 6% v/v ethanol were prepared. For the volatility evaluation, the ASTM distillation curve and vapor pressure of these mixtures were determined experimentally in order to predict the performance of the resulting fuels. When adding oxygenated compounds, the increase in vapor pressure was proportional to the additive qua... [more]

Due to the increasingly restrictive exhaust emissions requirements from conventional vehicles, the internal combustion engine start-up seems to be most important part of engine operation. The period immediately after starting the engine is the time when the exhaust emissions are highest, thus, this aspect is currently subject to heavy analysis. The article evaluates the impact of the engine thermal state during its start-up for a Euro 5 emission class vehicle type approval test. The engine thermal state during start-up turned out to have a crucial influence (throughout the approval test) on the results of the hydrocarbons road emission (a difference of about 1500%) and the road emission of carbon monoxide (63%). The remaining road exhaust emission values were less sensitive to the thermal state of the engine during start-up—the nitrogen oxides emission value increased by 18% (for a cold start compared to a hot start), and the road fuel consumption (and thus the emission of carbon dioxi... [more]

The energy crisis, an increasing concern of the industrial sector, is characterized by increased energy costs and low energy availability. As part of an effort to increase energy efficiency, the present study assessed the impact of applying lean tools on the energy consumption of a manufacturing organization. Using the Kaizen approach, the organization’s processes were analyzed to identify the main vulnerabilities and make the required changes to increase consumption performance. Several technical improvements were performed to reach increased energy efficiency. Results showed an energy efficiency increase; consumption was reduced by up to 7.5% in the production line, 3.5% in the extruder stage, and up to 20% for the injection stage of the manufacturing process. The results suggest that the organization’s energy reduction targets have been achieved. Standardization of procedures was useful in the development of Kaizen projects which could be applied with certain limitations. The implic... [more]

The recovery of vegetal waste for energy purposes is one of the ways to increase the amount of energy obtained from renewable sources. The Top-Lit Updraft (TLUD) gasification and combustion process is recognized as the least polluting of all other combustion processes, resulting in a sterile charcoal called biochar, which can be used as an amendment in agricultural soils. The purpose of this research was to determine the influence of excess air in the combustion area compared to the (theoretical) calculated requirement for a TLUD energy module. Most scientific publications on this topic recommend primary/secondary air flow rate ratios of 1/3 or 1/4. In this study, the two recommended ratios were tested, and it was found that better energy results correspond to the ratio of 1/3. For this 1/3 ratio, the investigations continued in order to optimize the combustion process. The results achieved demonstrate that the excess combustion air flow of 30% improves the performance of the energy mo... [more]

Natural gas is the primary source of energy, accounting for around 20% of the world’s energy production. It is also a key element in reducing CO2 emissions due to its key role in stabilizing renewable energy sources. At the same time, natural gas as a fossil fuel that emits CO2 should be limited. A natural candidate that can ensure the stabilization of RES and at the same time reduce the demand for fossil fuels is biogas. Successful use of biogas requires a thorough understanding of the potential, structure, and specifics of its sources and production technology. The presented study provides a perspective and a brief overview of the existing potential of biogas production. Poland was chosen as the case study and it was shown that almost 90% of the Polish biogas potential comes from sources with a capacity below 100 Nm3/h, which is the current minimum commercially available capacity of the biogas purification and liquefaction technologies. Consequently, full utilization of these sources... [more]

Residential coal combustion is a major source of air pollution in developing countries, including China. Indeed, precisely measuring the real-time emission of major air pollutants is often challenging and can hardly be repeated at a lab-scale. In this study, for the first time, two clean coals initiated from raw bituminous coal were burned for real-time estimation of air pollution characteristics and their thermal efficiencies in different stoves. Moreover, thermodynamic equilibrium simulations were investigated for slagging parameters using Factsage 7.1 at reaction temperature 800~1600 °C. Results revealed that the firepower of clean coals (Briquetted coal and Semi-coke) was much higher (2.2 kW and 2.1 kW) than raw coal (1.8 kW) in a traditional stove. However, the thermal efficiencies were remarkably increased (13.3% and 13.5%) in an improved stove for briquetted coal and semi-coke, respectively. The emission of major air pollutants including carbon monoxide (CO), sulfur dioxide (SO2... [more]

The article presents an overview of experimental layout design solutions and the general operation scheme of combined heat and power systems with a high-temperature solid oxide fuel cell (SOFC). This system is an environmentally friendly and energy-saving way to produce electricity and heat. The use of high-temperature SOFCs makes it possible to obtain an electrical efficiency of 45−55%. Combining the electrochemical and mechanical system can increase the total efficiency by up to 60−65% in a hybrid power plant. This article discusses the structure and relationship between the components of a hybrid power plant and various modification options for efficient power generation. The technological schemes for existing and tested hybrid power plants with an SOFC and gas turbine are presented and described in detail. When designing a hybrid power plant, the key factors are the choice of design, heat source, and fuel-reforming method; the design of a solid oxide fuel cell and the number of mod... [more]

There is increasing interest in migrating to a carbon-neutral power system that relies on renewable energy due to concerns about greenhouse gas emissions, energy shortages, and global warming. However, the increasing share of renewable energy has added volatility and uncertainty to power system operations. Introducing new devices and using flexible resources may help solve the problem, but expanding the domain of the problem can be another solution. Sector coupling, which integrates production, consumption, conversion, and storage by connecting various energy domains, could potentially meet the needs of each energy sector. It can also reduce the generation of surplus energy and unnecessary carbon emissions. As a result, sector coupling, an integrated energy system, increases the acceptance of renewable energy in the traditional power system and makes it carbon neutral. However, difficulties in large-scale integration, low conversion efficiency and economic feasibility remain obstacles.... [more]

Nuclear fusion is the gateway to a whole new paradigm of energy and is a strong candidate for the decarbonization of electricity generation on a global scale. With recent developments in high-temperature super-conducting magnets, the race is on to develop sub-systems which will support a commercially viable fusion reactor for use as a thermal power plant. The fusion of lighter elements creates an enormous amount of heat which must be transferred away from the reactor core. These intense conditions require novel approaches to efficiently transfer very high heat loads into useable thermal energy without compromising the structural integrity of the reactor core and the surrounding components. This report outlines the concept of a fundamental approach to solve the heat transfer problem as proposed by Commonwealth Fusion System’s design for a fusion reactor. A literature review was conducted for other applications that could serve as inspirations, as well as material properties and machinin... [more]

Conventional and cyclic unloading tests with different unloading rates were conducted to study the influences of unloading patterns and rates on the deformation characteristics and mechanical properties of tectonic coal. The results demonstrate that, under continuous unloading, a lower unloading rate promotes an increase in the circumferential strain but inhibits increases in axial strain. A lower unloading rate was found to be able to promote volume expansion under the cyclic unloading path, and the axial, circumferential, and volume strains increased stepwise with the unloading levels, but the increment of the strains decreased with the number of cycles in the same unloading level. It was easier for tectonic coal to reach the elastic limit by a low speed unloading rate when the unloading level was small, and volume dilatation was promoted when the unloading level was large. In both unloading patterns, the tangential modulus and the Poisson ratio were proportional to the unloading rat... [more]

The penetration of electric vehicles is becoming more and more widespread and recently electric buses and trains are fetching the attention of researchers and developers. In this review, we examine the charging systems applied to the fast charging of electric vehicles and buses as well as the charging strategies, mainly applied to electric buses. We also briefly delve into power topologies for a more electrified railway system where we discuss their different supply systems as well as their motor drive systems. Problems and charge challenges for electric buses and trains are discussed too.

This paper describes an energy management strategy for a DC microgrid that utilizes a hybrid renewable energy system (HRES) composed of a photovoltaic (PV) module, a wind turbine based on a permanent magnetic synchronous generator (PMSG), and a battery energy storage system (BESS). The strategy is designed to provide a flexible and reliable system architecture that ensures continuous power supply to loads under all conditions. The control scheme is based on the generation of reference source currents and the management of power flux. To optimize the supply−demand balance and ensure optimal power sharing, the strategy employs artificial intelligence algorithms that use previous data, constantly updated forecasts (such as weather forecasts and local production data), and other factors to control all system components in an optimal manner. A double-input single-output DC−DC converter is used to extract the maximum power point tracking (MPPT) from each source. This allows the converter to... [more]

Geothermal energy is a type of renewable energy that has rich reserves, is clean, environmentally friendly and has been widely used in the heating industry. The single-well closed-loop geothermal system is a technology with the characteristics of “taking heat without taking water” and is mainly used for geothermal energy heating. Although the heating requirements in the cold region of Northeast China are urgent, the traditional heating mode not only has high economic costs but also causes serious damage to the environment. Therefore, it is of important practical significance to change the heating structure and develop and utilize geothermal energy for heating according to local conditions. In this study, the actual operating single-well geothermal system in the Songyuan area of Jilin Province is used as a case study, and a numerical model is established based on the T2WELL simulation program. The flow production temperature and heat extraction response law of the single-well system in... [more]

In the present paper a new multi-objective optimisation procedure for the design of a shell-and-tube Latent Heat Thermal Energy Storage (LHTES) is proposed. A simple arrangement of a cylindrical shell with multiple vertical tubes has been examined. The optimisation considers, as design variables, the number of tubes, the tube internal radius and the device height-to-diameter ratio, H/D, while the storage volume is kept constant. This analysis aims to detect the set of solutions which optimises the LHTES performances evaluated in terms of charging and discharging times and overall thermal energy capacity. To accomplish the multi-objectives optimal thermal storage design, a simplified mathematical model of the LHTES has been employed. This model can evaluate the prescribed performances for a given set of design variables. The proposed optimisation procedure evaluates new solutions along the most promising directions in the design variables domain, leading to a significant improvement in... [more]

A bottom-up cost analysis for delivering utility-scale PV-generated electricity as hydrogen through pipelines and as electricity through power is undertaken. Techno-economic, generation, and demand data for California are used to calculate the levelized cost of transmitting (LCOT) energy and the levelized cost of electricity (LCOE) prior to distribution. High-voltage levels of 230 kV and 500 kV and 24-inch and 36-inch pipelines for 100 to 700 miles of transmission are considered. At 100 miles of transmission, the cost of transmission between each medium is comparable. At longer distances, the pipeline scenarios become increasingly cheaper at low utilization levels. The all-electric pathways utilizing battery energy storage systems can meet 95% of the load for as low as 356 USD/MWh, whereas when meeting 100% of load with the hydrogen gas turbine and fuel cell pathways, the costs are 278 and 322 USD/MWh, respectively.

Nanostructured materials have gained much attention in recent engineering and material- science research due to their unique structural makeup, which stands them out from their bulk counterparts. Their novel properties of tiny-size structural elements (molecules or crystallites, clusters) of nanoscale dimensions (1 to 100 nm) make them a perfect material for energy applications. The recent keen interest in nanostructured materials research by academia and industrial experts arises from the unique variable characteristics of increased electrical and thermal conductivity. This occurs as nanostructured materials undergo a transient process from infinite-extended solid to a particle of ascertainable numbers of atoms. The commercial and energy sectors are very interested in developing and expanding simple synthetic pathways for nanostructured-electrocatalysts materials to aid in optimizing the number of active regions. Over the decades, various techniques have been put forward to design and... [more]

This work aims to study the dynamic characteristics of an entire aero-engine casing by experiments using a new type of rotating exciter. New vibration sensor layout rules are proposed according to experimental results and vibration transmission characteristics. The vibration response of the aero-engine casing is carried out, and the vibration response of different casing measuring points is also studied. The finite element model of the engine casing’s structure is established to obtain the natural frequency of the whole aero-engine casing, which agrees well with the experimental measurement. We find that the vibration acceleration transmission value of the radial measuring point of bearing No. 1, but not the fan sensor, is more suitable for detecting the running state of the fan rotor. In addition, the sensor in the intermediate casing can detect the vibration of the high-pressure rotor. Bolt loosening of the flange has little effect on the vibration transmission characteristics of the... [more]

Energy is very important in daily life. The smart power system provides an energy management system using various techniques. Among other load types, campus microgrids are very important, and they consume large amounts of energy. Energy management systems in campus prosumer microgrids have been addressed in different works. A comprehensive study of previous works has not reviewed the architecture, tools, and energy storage systems of campus microgrids. In this paper, a survey of campus prosumer microgrids is presented considering their energy management schemes, optimization techniques, architectures, storage types, and design tools. The survey is comprised of one decade of past works for a true analysis. In the optimization techniques, deterministic and metaheuristic methods are reviewed considering their pros and cons. Smart grids are being installed in different campuses all over the world, and these are considered the best alternatives to conventional power systems. However, effici... [more]