Energy-intensive Research Articles

Influence of blasting charge distribution on the energy required for communition of rock

The most energy-intensive process in the mining industry is particle size reduction - comminution. The first phase of this process is blasting to fragment the rock from the initial Boussinesq's half-space size. Scientific literature demonstrates that the output of a blast in terms of fragment size distribution can be manipulated by varying the specific charge (powder factor) and charge distribution. This study focuses on the influence of blasting on the internal resistance of the blasted fragments; in particular the influence of the spatial distribution of charges. Small-scale blasts were performed on 14 marble blocks using different powder factors and charge distributions. Three control blocks were fragmented by mechanical means for comparison. The results show the correlations between charge distributions and the specific energy of mechanical comminution. Opportunities for adjusting charge diameter and distribution in opencast blasts to improve the performancet of comminution circuits are discussed.

Potential for Electrical Energy Savings in AC Systems by Utilizing Exhaust Heat from Outdoor Unit

This study explores the potential of utilizing waste heat from air conditioning systems, one of the largest consumers of electrical energy. Currently, most of the waste heat generated by outdoor units is typically released into the environment without being utilized, leading to missed energy-saving opportunities. This study analyzes the potential for improving electrical energy efficiency in air conditioning (AC) systems by harnessing this waste heat. Two primary approaches are evaluated: the first is the use of waste heat for domestic water heating, and the second is the conversion of heat into electrical energy using thermoelectric generators (TEG). The results of this research indicate that both methods have the potential to improve overall energy efficiency significantly. However, challenges related to conversion efficiency and integration of these technologies with AC systems require further, more specific studies. These findings are expected to contribute to more efficient and environmentally friendly cooling systems by optimizing technology and overcoming barriers to wider implementation.

Cross-Coupling of Gaseous Alkanes with (Hetero)Aryl Bromides via Dual Nickel/Photoredox Catalysis.

Gaseous alkanes represent the most abundant carbon-based chemical feedstocks in our planet. However, the intrinsic inertness of their C-H bonds has rendered the use of these alkanes very difficult for purposes beyond aerobic combustion and energy intensive processes. Thus, clean and energy-efficient transformations for their use in synthetic organic chemistry are still rare. Here we report a catalytic methodology for the direct cross-coupling of gaseous alkanes with (hetero)aryl bromides through the combination of metallaphotoredox-mediated hydrogen atom transfer and nickel catalysis. This protocol provides an efficient platform for the addition of short alkyl groups into diverse (hetero) aromatic rings, providing a wide range of high-value alkyl(hetero)arenes, and bypassing the longstanding need of using preactivated alkylating agents in C(sp2)-C(sp3) cross-couplings. The method features high chemoselectivity, regioselectivity and a remarkable functional group tolerance, operates under mild conditions, and exhibits operational simplicity.

Cross‐Coupling of Gaseous Alkanes with (Hetero)Aryl Bromides via Dual Nickel/Photoredox Catalysis

Gaseous alkanes represent the most abundant carbon‐based chemical feedstocks in our planet. However, the intrinsic inertness of their C‐H bonds has rendered the use of these alkanes very difficult for purposes beyond aerobic combustion and energy intensive processes. Thus, clean and energy‐efficient transformations for their use in synthetic organic chemistry are still rare. Here we report a catalytic methodology for the direct cross‐coupling of gaseous alkanes with (hetero)aryl bromides through the combination of metallaphotoredox‐mediated hydrogen atom transfer and nickel catalysis. This protocol provides an efficient platform for the addition of short alkyl groups into diverse (hetero) aromatic rings, providing a wide range of high‐value alkyl(hetero)arenes, and bypassing the longstanding need of using preactivated alkylating agents in C(sp2)‐C(sp3) cross‐couplings. The method features high chemoselectivity, regioselectivity and a remarkable functional group tolerance, operates under mild conditions, and exhibits operational simplicity

Thermodynamic performance analysis of a new air energy storage multigeneration system

This paper proposes a chemical looping hydrogen generation-solid oxide fuel cell combined cooling, heating, and power system that utilizes compressed air energy storage and liquefied natural gas, aiming to address the issues of instability in renewable energy power generation and waste of liquefied natural gas cold energy. The scheme achieves CO2 capture and efficient power generation while also addressing grid fluctuations and the utilization of waste cold energy. The compressed air energy storage system is employed to supply air centrally, eliminating the power consumption of traditional air compressors while improving discharging efficiency. Aspen Plus software and embedded Fortran are used for system simulation. The system is comprehensively evaluated through energy analysis, exergy analysis, and sensitivity analysis. The results indicate that the discharging efficiency, energy round-trip efficiency, and round-trip electrical efficiency are 87.56%, 81.57%, and 67.82%, respectively. The purity of CO2 capture is 99.72%. Sensitivity analysis indicates that the outlet pressure of the air storage tank and fuel flow are the main influencing parameters for system performance. Increasing the fuel flow can effectively enhance system power output, but efficiency will decrease. The outlet pressure primarily influences the power output of the gas turbine and discharging time. Overall, this system provides theoretical guidance and new ideas for efficient energy utilization.

The Application of Pinch Technology to a Novel Closed-Loop Spray Drying System with a Condenser and Reheater.

Spray drying is an energy-intensive process in industrial use, making energy recovery a critical focus for improving overall efficiency. This study investigates the potential of integrating heat-recovery systems, including an innovative air reheater, into a closed-loop spray-drying unit to maximise energy savings. Through detailed pinch analysis, the system achieved a very low approach temperature, averaging 3.48 K, which is significantly lower than that of conventional open-loop systems. The study quantifies the energy-recovery potential by demonstrating that the integration of heat-recovery components can reduce the external heating demand by up to 30%. This not only enhances heat-transfer efficiency but also lowers operational costs and reduces the system's environmental impact. The results suggest that closed-loop systems with air reheaters offer a scalable solution for improving energy efficiency across different industrial applications. The research highlights a new paradigm: focusing on latent energy within the system rather than adjusting individual operational variables.

Analysis and performance prediction of a building integrated photovoltaic thermal system with and without phase change material

Increasing energy demand in buildings in the last decade has led to more efficient usage of renewable energy. Building integrated photovoltaic/thermal systems is one of the effective ways of reducing energy consumption in buildings by providing heating, cooling, ventilation, hot water, and air. The enhancement of photovoltaic cell temperature reduces the electrical efficiency of photovoltaic panel systems. In this regard, the effects of cooling with air and phase change material layer are investigated in this study. The simulation of BIPV/T, PV, and heat pump was done in TRNSYS. As the main novelty of recent simulation, for the calculations of phase change material layer, MATLAB coupled with the TRNSYS, and Python software was used for the prediction process under the weather conditions of Sharurah, Saudi Arabia for 2022. Also, the performance of a building integrated photovoltaic/thermal system with a phase change material layer is predicted for 2024 and 2025 by the Random Forest machine learning method. The R squared, Root Mean Squared Error, and Mean Absolute Error are utilized for checking the accuracy of the model. Also, for more certainty, a validation was done on the simulated results of TRNSYS and the results showed high conformity of data. The simulated data for the first six months of 2022 showed that the maximum cooling effect happened in June with 25.47 °C and a 37.87 % reduction in photovoltaic cell temperature. Also, the best electrical efficiency improvement was 1.26 % while the thermal efficiency ranged from 29.65 % to 59.40 %, respectively. The predicted data was confirmed by R2, RMSE, and MAE equal to 96.64 %, 0.06 and 0.04. According to the simulation and predictions done, the annual electrical production of the building is achieved. The results indicate that, for the simulated system, about 29.7 %, 29.8 %, and 29.6 % of total energy utilization could be supplied by BIPV/T cooled with phase change material in 2022, 2024, and 2025, respectively.

Performance Assessment of Confined Tube Aerators in Parallel Configuration

Aeration plays a major role in the activated-sludge wastewater treatment process. Microbes require an oxygen-enriched environment to digest organic materials and remove nutrients from the wastewater stream. For providing this oxygen, artificial aeration is required, which is responsible for the majority of energy use in treatment plants. Typically, this is accomplished with diffused aerators, where pressurized air is forced through a porous medium at the bottom of deep basins, and bubbles float up through the water column transferring oxygen in the process. This is a relatively energy-intensive process, which is prone to fouling at the porous media. In this study, a Confined Tube Aeration (CTA) system is proposed, where a pump forces water through a Venturi injector, where air is naturally drawn in. At the Venturi discharge, the flow is diverted to a coiled tube in which oxygen transfer occurs. This study analyzes the effect of parallelizing the CTA system with multiple injectors and at varying pump speeds (flow rates). Using experimental and analytical means, the maximum standard aeration efficiency was found to be with three injectors in parallel, at maximum pump speed, and utilizing a CTA with diameter 31.75 mm and length 3.048 m. This value was found to be 0.542 kg O2/kWh, and represents a 25% increase over the single-injector case. Although the analyses herein utilize a relatively small (0.746 kW) pump, these results indicate that CTA systems may scale well to larger pump sizes necessary for full-scale municipal wastewater treatment.

Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt-Copper Mixed Single-Atom/Cluster Catalyst with Synergistic Effects.

Electrochemical conversion of waste nitrate (NO3 -) to ammonia (NH3) for environmental applications, such as carbon-neutral energy sources and hydrogen carriers, is a promising alternative to the energy-intensive Haber-Bosch process. However, increasing the energy efficiency is limited by the high overpotential and selectivity. Herein, a Co─Cu mixed single-atom/cluster catalyst (Co─Cu SCC) is demonstrated-with well-dispersed Co and Cu active sites anchored on a carbon support-that delivers high NH3 Faradaic efficiency of 91.2% at low potential (-0.3V vs. RHE) due to synergism between the heterogenous active sites. Electrochemical analyses reveal that Cu in Co─Cu SCC preferentially catalyzes the NO3 --to-NO2 - pathway, whereupon Co catalyzes the NO2 --to-NH3 pathway. This tandem electroreduction bypasses the rate-determining steps (RDSs) for Co and Cu to lower the reaction energy barrier and surpass scaling relationship limitations. The electrocatalytic performance is amplified by the subnanoscale catalyst to increase the partial current density of NH3 by 2.3 and 5.4 times compared to those of individual Co, Cu single-atom/cluster catalysts (Co SCC, Cu SCC), respectively. This Co─Cu SCC is operated stably for 32 h in a long-term bipolar membrane (BPM)-based membrane electrode assembly (MEA) system for high-concentration NH3 synthesis to produce over 1m NH3 for conversion into high-purity NH4Cl at 2.1g day-1.

Optimal Control Allocation for Distributed Electric Propulsion in a Series/Parallel Partial Hybrid Powertrain

Abstract The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a NASA concept transport aircraft representative of technology anticipated for a 2040 entry-into-service date. The powertrain consists of a single thrust-producing geared turbofan engine with generators driving a series/parallel partial hybrid power/propulsion system. The architecture includes 16 underwing contrarotating fans, eight on each side. The distributed fans can be used by the flight control system to augment or replace the rudder function. This paper sets up the optimal control problem of setpoint determination for individual wingfans in the distributed propulsion system, accounting for electrical string efficiencies, saturations, and failures. The solution minimizes power consumption while maintaining thrust and torque on the airframe for maneuvering. Additionally, thrust that would have been lost due to temporary fan speed or power saturation is optimally redistributed to maintain overall desired thrust and torque on the aircraft. A simulation of a coordinated turn utilizing the distributed electric propulsion for yaw rate control in a multiple wingfan failure scenario demonstrates the robustness of the powertrain design to failures and helps define its limitations.

Hydrogen Generation by Nickel Electrodes Coated with Linear Patterns of PTFE

Previous studies have shown that partially coating electrode surfaces with patterns of ‘islands’ of hydrophobic tetrafluoroethylene (PTFE; Teflon) may lead to more energy efficient gas generation. This occurred because the gas bubbles formed preferentially on the PTFE, thereby freeing up the catalytically active metallic surfaces to produce the gas more efficiently. This work examined electrochemically induced hydrogen bubble formation on a nickel electrode surface that had been coated with linear patterns of PTFE. The impact of the PTFE line size (width) and degree of coverage was examined and analyzed. No improvement in electrical energy efficiency was observed up to 15 mA/cm2 when comparing the PTFE-coated electrodes with the control bare uncoated electrode. However, increasing PTFE coverage up to 15% generally improved electrolysis performance. Moreover, samples with 50% wider lines performed better (at the equivalent PTFE coverage), yielding an overpotential decline of up to 3.9% depending on the PTFE coverage. A ‘bubble-scavenging’ phenomenon was also observed, wherein bubbles present on the PTFE lines rapidly shrunk until they disappeared.

Energy and exergy analysis of a parabolic trough driven an ORC cycle for heat and power supply

Converting solar energy using the Parabolic Trough Collector (PTC) to produce electrical energy and supply industrial heat is one of the most prominent and most popular sustainable and renewable, widely used throughout the worldwide due to its effectiveness and benefit returns. For this reason, this study aims to investigate the effectiveness of these power plants under a specific climatic conditions and analysis the results come out from the simulation using an EES developed model. The analysis investigates the energy and exergy of the PTC plant coupled with Turboden ORC cycle. The presented model allows us to preview the theoretical results and derive the expected results smoothly, with the possibility of development for a better control of the use of renewable energies in the industrial field. The thermal efficiency of the ORC cycle increases as the heat output increases until it reaches an almost constant value above 2801 [kW] in heat output with a output capacity of the ORC cycle about 1 [MW].

Performance Assessment of Hybrid PV/PVT Collectors Incorporating Natural Water-Cooling Circulation

The present work investigates outdoor recitals and characteristics of hybrid PVT collectors and compares using non-cooled Photo-Voltaic (PV) collectors on a clear day at Khamshet, Pune, India. The hybrid PVT is designed, fabricated, and mounted on the terraces of the institute to ensure maximum radiation will fall on PV and PVT collector. The spiral circular thermal absorber is manufactured and placed at the backside of the photovoltaic to lower the surface temperature by extracting heat through water flowing through the absorber. The experimentation is performed at 0.03 kg/sec of water and natural cooling circulation is adopted for experimental work. The uncertainty analysis is also performed to ensure the accuracy of the results. The investigation observed that the PVT collector is superior to the PV system from electrical and thermal efficiency viewpoints. The cutback in PV module temperature was observed in a variation of 8.7-13.7%, which justifies using the water-cooling technique. The maximum electrical and thermal efficiency of 6.93 % and 52.7% were found for PVT collectors while sole maximum electrical efficiency of 5.62 % was found for PV collectors. This study concludes that the PVT collector has better performance characteristics than the PV collector and can be further enhanced using different fluid and thermal absorber designs.

Examination of the Peaceful Uses of Nuclear Energy in Turkish Legislation

Population growth, industrialization and technological advances increase the demand for energy. Due to problems such as global warming, environmental pollution and destruction, the trend towards alternative energy sources continues on a global scale. For this reason, the use of nuclear energy, one of the secondary energy sources, has tended to increase in recent years. Reasons such as the geographically uneven geographical distribution of resources that are raw materials for energy among countries and their exhaustibility, fluctuations in energy prices and the economical production of nuclear energy are among the reasons why countries in the world turn to nuclear energy. A number of accidents at nuclear power plants have had a negative impact on the perception of nuclear power plants, but for different reasons, nuclear energy is gaining popularity again. Nuclear power plants are the first thing that comes to mind when it comes to nuclear power, but it is also used effectively in medical treatments and applications of various branches of science as well as energy production. In global energy production; the fact that it aims to reduce carbon emissions by providing more energy production within the scope of sustainability, the continuous and uninterrupted continuation of electricity production using nuclear, the production of electricity at more affordable costs in nuclear power plants compared to other power plants (thermal, renewable, etc.), the fact that greenhouse gas emissions are almost negligible, and the use of nuclear technology in many fields such as physics, medicine, transportation, agriculture as well as energy production have made nuclear energy back on the agenda of countries in recent years. In nuclear energy, nuclear waste and their storage processes continue to be discussed as a problem in this process. For these reasons, the possibility of peaceful use of nuclear power has been questioned in academic platforms and various criteria have been determined This article examines Turkey's compliance with the criteria for the peaceful use of nuclear energy and clarifies the development process in this regard. Turkey's legislation on nuclear energy, international conventions, nuclear safety, radiation control criteria and compliance with national legislation will be examined.

Investigation on the performance of a solar multifunctional photovoltaic/thermal window combining photocatalytic oxidation technology

In response to the challenges of high energy consumption and poor indoor air quality, a novel solar multifunctional louver window has been proposed. This study developed a numerical model to examine the effects of environmental variables and louver angles on the thermal, electrical, and degradation performance of the system. Additionally, an exergy-based evaluative framework was introduced to account for the varying qualities of energy in assessing the performance of solar multifunctional windows. Finally, a comprehensive evaluation was conducted using this framework. The results demonstrate that the exergy efficiency of the solar multifunctional window can be maintained at 20 % or higher, even under reduced solar irradiation, delivering high-quality energy. Lower environmental temperatures and solar radiation intensities were found to negatively affect ventilation, thermal efficiency, and air purification capacity. The thermal, purification, and electrical efficiencies were influenced by the louver angle to varying extents. In terms of air purification, the window achieved the highest Clean Air Delivery Rate (CADR) at louver angles between 80° and 90°, thereby enhancing air purification performance.

Second-Order Microring Filter with Large Free-Spectral-Range and Wavelength-Tunable-Range over 50 nm

The high-order microring filter has been proposed for a larger free spectral range (FSR) compared with the single microring filter; therefore, it has great potential to be used in wavelength division multiplexing (WDM) systems. In this article, we have designed and fabricated a second-order microring filter made up of two rings connected in series with two Ti thermal heaters deposited above them. The large FSR of 56.8 nm is obtained by decreasing the difference of the radii between the two series rings, achieving similar FSRs to that of higher-order filters but with a simpler and more compact design. The average electrical tuning efficiencies of the two heaters are 0.186 nm/mW and 0.207 nm/mW, and the center wavelength of the filter can be tuned over the entire FSR with an applied electrical power of less than 40 mW.

Performance Analysis and Optimization of a Channeled Photovoltaic Thermal System with Fin Absorbers and Combined Bi-Fluid Cooling

The conversion efficiency of photovoltaic (PV) cells can be increased by reducing high temperatures with appropriate cooling. Passive cooling systems using air, water, ethylene glycol, and air/water+TiO2 nano bi-fluid froth in the duct channel have been studied, but an overall assessment is essential for its possible application. In the present work, a numerical study is adopted to investigate the impact of the fluid-duct channel type on the electrical and thermal efficiency of the photovoltaic thermal (PVT) collector. Such investigation is achieved by means of a MATLAB R2022b code based on the Runge–Kutta (RK4) method. Four kinds of fluid duct channels are used to optimize the best fluid for improving the overall efficiency of the investigated PVT system. The numerical validation of the proposed model has been made by comparing the numerical and experimental results reported in the literature. The outcomes indicate that varying the duct channel nature affects mainly the electrical and thermal efficiency of the PVT collector. Our results validate that the nature of the fluid affects weakly the electrical efficiency, whereas the thermal efficiency is strongly affected. Accordingly, it is observed that PVT collectors based on nano bi-fluid air/water+TiO2 give the best performance. In this context, an appreciable increase in the overall efficiency of 22% is observed when the water+TiO2 fluid is substituted by air/ water+TiO2 nano bi-fluid. Therefore, these motivating results make the PVT nano bi-fluid efficient and suitable for solar photovoltaic thermal applications since this system exhibits a daily overall efficiency of about 56.96%. The present work proves that controlling the design, cooling technique, and nature of the cooling fluid used is a crucial factor for improving the electrical, thermal, and overall efficiency of the PVT systems.

A study on 5-cycle fuel economy prediction model of electric vehicles using numerical simulation

This paper is a study on 5-cycle fuel economy prediction model of electric vehicles using numerical simulation. It aims to develop a prediction model for the energy efficiency of electric vehicles and compare it with the results of chassis dynamometer tests. Driving tests were conducted on a chassis dynamometer, which included various test cycles of the 5-cycle test. Using MATLAB Simulink, a vehicle dynamics analysis model for electric vehicles was constructed, and analytical research was conducted focusing on light-duty electric vehicles. By comparing and analyzing the experimental data obtained from the chassis dynamometer with the data calculated through simulation, it is possible to verify the accuracy of the electric vehicle energy efficiency prediction model. And the reliability of the simulation model was secured by comparing the experimental data obtained through chassis dynamometer test with the simulation results of the developed electric vehicle energy efficiency prediction model. There is good agreement between the experimental and simulation results. In most areas, the error rate remains below 3 %, indicating that the simulation model closely follows the experimental results from the chassis dynamometer. Based on these results, it is expected that the developed simulation model can be utilized for measuring the energy efficiency of electric vehicles.

Comparison of Levitation Properties between Bulk High-Temperature Superconductor Blocks and High-Temperature Superconductor Tape Stacks Prepared from Commercial Coated Conductors.

Bulk high-temperature superconductors (HTSs) such as REBa2Cu3O7-x (REBCO, RE = Y, Gd) are commonly used in rotationally symmetric superconducting magnetic bearings. However, such bulks have several disadvantages such as brittleness, limited availability and high costs due to the time-consuming and energy-intensive fabrication process. Alternatively, tape stacks of HTS-coated conductors might be used for these devices promising an improved bearing efficiency due to a simplification of manufacturing processes for the required shapes, higher mechanical strength, improved thermal performance, higher availability and therefore potentially reduced costs. Hence, tape stacks with a base area of (12 × 12) mm2 and a height of up to 12 mm were prepared and compared to commercial bulks of the same size. The trapped field measurements at 77 K showed slightly higher values for the tape stacks if compared to bulks with the same size. Afterwards, the maximum levitation forces in zero field (ZFC) and field cooling (FC) modes were measured while approaching a permanent magnet, which allows the stiffness in the vertical and lateral directions to be determined. Similar levitation forces were measured in the vertical direction for bulk samples and tape stacks in ZFC and FC modes, whereas the lateral forces were almost zero for stacks with the REBCO films parallel to the magnet. A 90° rotation of the tape stacks with respect to the magnet results in the opposite behavior, i.e., a high lateral but negligible vertical stiffness. This anisotropy originates from the arrangement of decoupled superconducting layers in the tape stacks. Therefore, a combination of stacks with vertical and lateral alignment is required for stable levitation in a bearing.

Innovative PEEK in Dentistry of Enhanced Adhesion and Sustainability through AI-Driven Surface Treatments.

This research investigates using Polyether ether ketone (PEEK) in dental prosthetics, focusing on enhancing the mechanical properties, adhesion capabilities, and environmental sustainability through AI-driven data analysis and advanced surface treatments. The objectives include improving PEEK's adhesion to dental types of cement, assessing its biocompatibility, and evaluating its environmental impact compared to traditional materials. The methodologies employed involve surface treatments such as plasma treatment and chemical etching, mechanical testing under ASTM standards, biocompatibility assessments, and lifecycle analysis. AI models predict and optimize mechanical properties based on extensive data. Significant findings indicate that surface-treated PEEK exhibits superior adhesion properties, maintaining robust mechanical integrity with no cytotoxic effects and supporting its use in direct contact with human tissues. Lifecycle analysis suggests PEEK offers a reduced environmental footprint due to lower energy-intensive production processes and recyclability. AI-driven analysis further enhances the material's performance prediction and optimization, ensuring better clinical outcomes. The study concludes that with improved surface treatments and AI optimization, PEEK is a promising alternative to conventional dental materials, combining enhanced performance with environmental sustainability, paving the way for broader acceptance in dental applications.