Eco-friendly Operation Research Articles

Analysis of a self-sufficient photovoltaic system for a remote, off-grid community

Background The escalating global population, surpassing seven billion in 2012, amplifies the strain on existing resources for food, housing, and conventional energy. Addressing these challenges requires the development of economically and environmentally viable renewable energy technologies. Photovoltaic (PV) solar modules stand out for their eco-friendly operation and reliability. In off-grid communities, stand-alone PV systems, coupled with battery storage, play a pivotal role in meeting electrical energy needs. Methods This study enhances the understanding of stand-alone PV systems through modeling and simulation using MATLAB software. A multi-crystalline PV system, specifically the Kyocera KC130GT, is investigated under varying conditions, and a pulse width modulation (PWM) controller is employed for battery charging. Results The study reveals profound effects on energy production based on the I-V and P-V characteristics of the modeled system when a PWM controller is utilized. The system demonstrates successful energy generation under different conditions, accounting for temperature variations and PV battery voltage mismatches. Conclusion The simulated model serves as a versatile system capable of detecting different conditions in varying light and temperature scenarios. Effective temperature monitoring, voltage adjustment using a suitable charger controller, and the selection of optimal materials for solar modules can significantly enhance the system’s efficiency. The results emphasize the importance of careful consideration of PV system sizing corresponding to battery capacity for improved solar system efficiency. While the cost of the modeled stand-alone PV system is currently low, scalability to larger projects may incur increased costs due to the high prices of photovoltaic panels, batteries, and other components.

Optimizing vertical ground heat exchanger modelling through GPU-accelerated computation strategies

Enhancing Vertical Ground Heat Exchanger (VGHE) modelling for efficient Vertical Ground-Coupled Heat Pump (VGCHP) systems, renowned for their eco-friendly operation, has garnered significant attention. Optimally designing and sustaining the long-term efficiency of VGCHP systems necessitates rigorous, protracted VGHE modelling, a process fraught with computational intensity. To surmount this challenge, this contribution introduces an accelerated VGHE modelling paradigm grounded in Graphics Processing Unit (GPU) processing. This entails employing the Finite Line Source (FLS) model based on Fast Fourier Transform (FFT). To ameliorate computational demands, the processing capabilities of both Central Processing Units (CPUs) and GPUs are harnessed, leveraging CPU- and GPU-based FFT and inverse FFT (IFFT). Hybrid and non-hybrid processing modes are explored, differentiating between CPU- and GPU-based FFT in non-hybrid scenarios, while hybrid approaches combine both for distinct simulation periods. By scrutinizing two processing systems with varying specifications, diverse CPU- and GPU-based FFT combinations are assessed. Findings unequivocally underscore the superiority of CPU-based FFT for initial years, succeeded by GPU-based FFT for ensuing years, in terms of computational efficiency. The efficacy of the hybrid computation approach is demonstrated through a reduction of total computational time in 20-year VGCHP operation simulations by up to 33.5 % compared to conventional CPU-based FFT methods.

An efficient and eco-friendly operation mode for container transshipments through optimizing the inter-terminal truck routing problem

To enhance efficiency and reduce carbon emissions of waterway-waterway transshipments for a multi-terminal port group, a crucial strategic planning issue lies in determining whether a centralized or distributed mode of feeder vessel service is more efficient and eco-friendly. This paper proposes a two-stage integer-optimized model to optimize intra- and inter-terminal operations and determine the most effective mode of operation for feeder vessel services. Our model integrates the multi-terminal berth allocation problem and inter-terminal transportation (ITT), considering different cases of transshipment flows. To address this optimization problem, we develop a heuristic approach based on genetic and adaptive large neighborhood search algorithms, which is ideal method for large-scale scenarios. In our case study, the proposed optimization model and heuristic methods were adopted to determine the best operation mode for North Operation Area in Shanghai Yangshan Deep-Water Port (namely Yangshan Phase V). The results indicate that Yangshan Phase V should operate as a feeder vessel service terminal, providing primary feeder vessel services and complementary liner vessel services. This development plan not only minimizes container transshipment delays and overall ITT costs, but also helps reduce approximately 707.46 tons of annual carbon emissions caused by ITT at Yangshan Deep-Water Port.

Pre-oxidized ultramicroporous carbon cloth with ultrahigh volumetric capacity and ultralong lifespan for capacitive desalination

Capacitive deionization is a promising desalination technique to tackle with freshwater scarcity, due to its facile, energy-efficient and eco-friendly operation. Carbon materials are primary electrode materials in capacitive deionization devices; however, their practical applications are limited by the low salt adsorption capacity and poor cycling stability. Here, we report a pre-oxidized strategy to significantly improve the salt adsorption capacity and cycling lifespan of carbon clothes. By the simple pre-oxidation treatment, it creates abundant ultramicropores and a superhydrophilic surface, which lead to a high salt adsorption capacity (31.5 mg g−1 and 13 mg cm−3) in 0.01 M NaCl aqueous solution. Moreover, the surface of each carbon fiber is oxidized, combined with a high mechanical strength, resulting in a stable surface during the cycling process. The retention rate is 74% even after 5000 adsorption/desorption cycles in diluted seawater. This work provides a new avenue to the design of high-performance, low-cost, and durable electrodes for capacitive deionization applications.

Deep-learning-based multistate monitoring method of belt conveyor turning section

During transportation, bulk materials are susceptible to spillage due to equipment instability and environmental factors, resulting in increased maintenance costs and environmental pollution. Thus, intelligent and efficient condition monitoring is crucial for maintaining operational efficiency of transfer equipment. It facilitates the timely identification of potential safety hazards, preventing accidents from occurring or their impact from spreading, thereby minimizing production and maintenance costs. This study presents a deep-learning-based multioperation synchronous monitoring method suitable for belt conveyors that integrate target segmentation and detection networks to simultaneously diagnose belt deviation, measure conveying load, identify idlers, and do other tasks on a self-made dataset. This method effectively reduces the complexity of multistate simultaneous monitoring and monitoring costs, thereby avoiding environmental pollution caused by transportation accidents. Experimental results show that the segmentation accuracy of the proposed method can be up to 88.72%, with a detection accuracy of 91.3% and an overall inference speed of 90.9 frames per second. Furthermore, by extending the dataset, the proposed method can incorporate additional tasks, such as belt damage, scattered material, and foreign object identifications. This study has practical significance in ensuring the normal and eco-friendly operation of bulk material transportation. Our source dataset is available at https://github.com/zhangzhangzhang1618/dataset-for-turnning-section

Novel Synthesis of CuO/GO Nanocomposites and Their Photocatalytic Potential in the Degradation of Hazardous Industrial Effluents.

Photocatalytic degradation of dyes has been the subject of extensive study due to its low cost, eco-friendly operation, and absence of secondary pollutants. Copper oxide/graphene oxide (CuO/GO) nanocomposites are emerging as a new class of fascinating materials due to their low cost, nontoxicity, and distinctive properties such as a narrow band gap and good sunlight absorbency. In this study, copper oxide (CuO), graphene oxide (GO), and CuO/GO were synthesized successfully. X-ray diffractometer (XRD) and Fourier transform infrared (FTIR) spectroscopy confirm the oxidation and production of GO from the graphene of lead pencil. According to the morphological analysis of nanocomposites, CuO nanoparticles of sizes ≤20 nm on the GO sheets were evenly adorned and distributed. Nanocomposites of different CuO:GO ratios (1:1 up to 5:1) were applied for the photocatalytic degradation of methyl red (MR). CuO:GO(1:1) nanocomposites achieved 84% MR dye removal, while CuO:GO(5:1) nanocomposites achieved the highest value (95.48%). The thermodynamic parameters of the reaction for CuO:GO(5:1) were evaluated using the Van't Hoff equation and the activation energy was found to be 44.186 kJ/mol. The reusability test of the nanocomposites showed high stability even after seven cycles. CuO/GO catalysts can be used in the photodegradation of organic pollutants in wastewater at room temperature due to their excellent properties, simple synthesis process, and low cost.

Regulating Spin Polarization through Cationic Vacancy Defects in Bi4Ti3O12 for Enhanced Molecular Oxygen Activation.

Molecular oxygen (O2) activation technology is of great significance in environmental purification due to its eco-friendly operation and cost-effective nature. However, the activation of O2 is limited by spin-forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect-rich Bi4Ti3O12 (BTO-MV2) catalysts containing Ti vacancies (VTi) for O2 activation in water purification. The VTi on BTO nanosheets can induce electron spin polarization, increasing the number of spin-down photogenerated electrons and reducing the recombination of electron-hole pairs. An active surface VTi is also formed, serving as a center for adsorbing O2 and extracting electrons, effectively generating •OH, O2•- and 1O2. The degradation rate constant of tetracycline achieved by BTO-MV2 is 3.3 times faster than BTO, indicating a satisfactory prospect for practical application. This work provides an efficient pathway to activate molecular oxygen by constructing new active sites through cationic vacancy modification technology.

Energy-sharing operation strategy of multi-district integrated energy systems considering carbon and renewable energy certificate trading

District integrated energy systems (IESs) have proceeded to the practice stage. A day-ahead (DA) coordinated operation strategy of multi-district IESs is proposed when the entities participate in the energy market (EM), the spinning reserve market (SRM), the natural gas market, the carbon market, and the renewable energy certificate (REC) market simultaneously. We adopt the scenario-based stochastic programming method and the two-settlement mechanism to measure the uncertainties brought by electricity prices, photovoltaic (PV) outputs, and loads. Considering the topologies of electricity, heating, and cooling networks, the energy-sharing mechanism and the integrated demand response (IDR) mechanism are both implemented. We study the overlapped benefits of renewable energy generation (REG) from carbon and REC markets and propose a concept of the green index (GI). Case studies demonstrate that the proposed strategy model and the evaluation indicator can not only contribute to the economical and eco-friendly operation of the multi-district league (MDL), but also stimulate the coupling and complementarity of multiple energies.

Design of cascade refrigerant process utilizing CO2 and NH3 to remove volatile organic compounds

Volatile Organic Compounds (VOC) are organic substances that evaporate from crude oil. About 0.08–0.15 % of the crude oil loaded into the ship is released as VOCs, which indicates that 50–200 tons of VOC are generated per loading. The recovery of VOCs generated by crude oil loading is essential to avoid any environmental issues. In this study, we developed the VOCs recovery process based on the selective condensation of VOCs. The process was modeled using Aspen HYSYS V10, and economic evaluation methods including CAPEX, OPEX, and benefits obtained by utilizing VOCs were conducted to analyze the economic effect of increasing the condensation temperature. Moreover, this system was optimized to increase the efficiency of the refrigerant cycle at a predetermined condensation temperature based on an economic evaluation. We investigated carbon dioxide and ammonia, which is eco-friendly and can be used in ammonia-powered ships with on-board CCS system, to replace propylene refrigerant. COP (Coefficient of Performance) was optimized when modifying the design of the refrigerant process such as mixed refrigerant and cascade refrigeration. As a result, using a cascade refrigerant system with carbon dioxide and ammonia exhibits a higher process efficiency than that of the existing propylene refrigerant. Using the proposed cascade refrigerant system using carbon dioxide and ammonia will enable a more efficient and eco-friendly operation of the VOC recovery system

Tuning Model Predictive Control for Rigorous Operation of the Dalsfoss Hydropower Plant

Model predictive control is considered an attractive control strategy for the operation of hydropower station systems. It is due to the operational constraints or requirements of the hydropower system for safe and eco-friendly operation. However, it is mandatory to tune the model predictive control to achieve its best and most efficient performance. This paper determines the appropriate tunning on the weight parameters and the length of the prediction horizon for implementing model predictive control on the Dalsfoss hydropower system. For that, several test sets of the weight parameter for the optimal control problem and different lengths of the prediction horizon are simulated and compared.

Characterization and optimization analysis on surface finish and energy consumption in turning of Al-4032/GMP MMC produced by stir casting

Control of energy expenditure in computer numerical control (CNC) machining is needed for eco-friendly operation of machining operations. Production industries deeply emphasize the improvement of productivity and saving in cost. The aluminum-based metal matrix composites (AMCs) can be substituted for metals for their mechanical properties in several applications. However, to bring in composite to usage, generally demand certain machining operation, which is quite challenging. This paper presents fabrication, characterization, and machining (turning) of Al-4032/6%GMP (granite marble powder) composite. Optical micrographs (OM) and scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDAX) have been used for the portrayal of the composite microstructure, surface topography, and fracture behavior. Also, mechanical characterization (tensile strength, micro-hardness, and impact strength) of the fabricated AMC has been carried out. The AMC samples have been examined for machinability for CNC turning operation. Cutting speed, feed rate, and depth of cut are the cutting parameters selected for the machining experiments. The response surface methodology (RSM)-based desirability function has been used to obtain the best combination of parameters for achieving the desired objectives. Experimental results demonstrate the built-up edge (BUE) formation on cutting insert and interfacial bonding of particles on workpiece surface at low cutting speed. Generally, smooth cutting operation has been observed at cutting speeds above 100 m/min. Best surface finish (1.38 μm) and minimum energy consumption (0.27 kWh) have been observed at cutting speed 176 m/min, feed rate 0.15 mm/rev, and depth of cut 0.45 mm.

Research on Seepage Field and Slope Stability Considering Heterogeneous Characteristics of Waste Piles: A Less Costly Way to Reduce High Leachate Levels and Avoid Accidents

Due to the characteristics of high heap and large volume, the complex layers of waste, high-water level of leachate, environmental pollution, and slope instability are easily produced. Although many researchers have studied landfill two-dimensional leachate migration law, three-dimensional seepage and stability of landfill sites have been rarely studied. This paper focuses on the heterogeneous characteristics of the landfill piles and analyzes the seepage field and slope stability of the landfill using statistical and numerical analysis methods. The calculated results are compared with the field measurement and literature research data to verify the reliability of the model, which may provide the basis for the design and safe and eco-friendly operation of the landfill. Taking an actual landfill as the research object, the saturated–unsaturated transient model of heterogeneous waste is applied to practical engineering. Considering the landfill process and heterogeneous permeability, the calculated maximum water level is higher. Compared with the homogeneous material, the difference in the water level of each waste layer is about 0.08∼1.88 m, which is not good for the stability of the landfill. Combined with the engineering characteristic distribution of a landfill, the heterogeneous stability model is applied to the actual project to study the influence of different unit weight and shear strength distribution on landfill stability. The established model is suitable for the study of two-dimensional and three-dimensional slope stability of landfill sites. Through the slope stability analysis of the three-dimensional landfill site, it is found that the bank slope of the reservoir is steep and prone to instability failure. In most studies, only the instability of the landfill is of concern, but the bank failure is ignored. In the process of landfill operation and management, while considering the capacity of the landfill, the stability of the bank slope should also be paid attention to, and if necessary, bank slope reinforcement or slope ratio improvement should be carried out.

PREPARATION OF 2,4,5-TRIARYLIMIDAZOLE DERIVATIVES USING GREEN Syzygium Cumini SEED CATALYST

A simple, efficient, one-pot, and green synthesis of 2, 4, 5-triaryl imidazole was carried by three constituent reactions of benzil, ammonium acetate, and substituted aromatic aldehyde by using Syzygium cumini seed extract as a catalyst under reflux. The aqueous extract of Syzygium cumini seed as a biocatalyst is associated with high to excellent yield, green synthetic roughness, low reaction time, and eco-friendly operation. The catalyst contains different phytochemical contents, which are detrimental to improving the acidity of aqueous extract. The seed extract is nonhazardous, non-inflammable, low-cost, and environmentally green. All synthesized compounds were characterized by sophisticated spectroscopic techniques such as FT-IR, 1H-NMR, 13C-NMR, and Mass spectrometry.

Energy and Carbon Emission Efficiency Prediction: Applications in Future Transport Manufacturing

The long-term impact of high-energy consumption in the manufacturing sector results in adverse environmental effects. Energy consumption and carbon emission prediction in the production environment is an essential requirement to mitigate climate change. The aim of this paper is to evaluate, model, construct, and validate the electricity generated data errors of an automotive component manufacturing company in South Africa for prediction of future transport manufacturing energy consumption and carbon emissions. The energy consumption and carbon emission data of an automotive component manufacturing company were explored for decision making, using data from 2016 to 2018 for prediction of future transport manufacturing energy consumption. The result is an ARIMA model with regression-correlated error fittings in the generalized least squares estimation of future forecast values for five years. The result is validated with RSS, showing an improvement of 89.61% in AR and 99.1% in MA when combined and an RMSE value of 449.8932 at a confidence level of 95%. This paper proposes a model for efficient prediction of energy consumption and carbon emissions for better decision making and utilize appropriate precautions to improve eco-friendly operation.

Experimental investigation on an air source heat pump system with coupled liquid-storage gas-liquid separator regarding heating and defrosting performance

Air source heat pump (ASHP) has advantages of high efficiency, eco-friendly operation, and convenient installation, but frost accumulation on the outdoor heat exchanger is one of the basic concerns about its operation. Reverse cycle defrosting (RCD) is widely used for defrosting, however, when RCD begins and ends, the four-way reversing valve quickly switches and the system pressure needs to be rebalanced which will cause the incomplete evaporation of refrigerant into the compressor. Thus, it leads to the decrease of the performance of the ASHP system during RCD. In order to improve the performance of RCD, this study proposes an ASHP defrosting system with coupled liquid-storage gas-liquid separator. An obvious advantage of the proposed system is retarding frosting, reducing defrosting time and increasing the heating capacity and coefficient of performance (COP) of the ASHP system thus reducing the number of defrosting cycles. And the proposed system can improve indoor thermal comfort during defrosting. Experiments show that compared with the original system, the proposed system delays frosting by 30 min and reduces the defrosting time by 74 s (22.7%), improving the heating capacity and COP by 6.78% and 12.8% respectively. Moreover, the proposed system with the coupled liquid-storage gas-liquid separator is economically friendly, which further benefits its practical applications.

Quantitative assessment of ecological operation effects based on flood pulses and ecology-economic coupling model: a case study of Three Gorges Reservoir, China

Abstract Flood pulses are closely related to river ecosystem health. Reservoirs bring many benefits to flood control, power generation, shipping etc., but their attenuation effects on runoff flood pulses should not be ignored. Ecological operation can effectively reduce some negative ecological impacts brought by the reservoir. However, the inability to quantitatively assess ecological effects hinders the promotion of ecological operation in reservoir management. To solve this problem, we proposed 11 flood pulse indicators (FPI), a random simulation method and an ecology-economy coupling model in this study. In addition, we used four major Chinese carps as indicator species and the Three Gorges Reservoir as a case study to test the role of flood pulses in improving the ecological operation effects of the reservoir from the fish protection perspective. The results show that: (1) FPI can be controlled by the reservoir and reflect the flood pulse characteristics of runoff. (2) Random simulation method guides managers to optimize the discharge and formulate eco-friendly operation schemes. (3) Ecology-economy coupling model helps managers analyze the relationship between ecological operation effects and economic benefits. A comprehensive assessment can improve the acceptance of ecological operation, which is conducive to the sustainable development of river ecosystem.

The Complexity of Global Tourism and Greenhouse Gases

This study investigates the complexity of global tourism (tourism arrivals and tourism departures) of 93 countries by considering the greenhouse gases characteristics (carbon dioxide emission, nitrous oxide, methane, and fluorinated gas) in 2012 using a complex adaptive system approach. The results of the study indicated that greenhouse gases characteristics and global tourism interact in a nonlinear manner. Results showed that the indices of global tourism are unpredictable for a certain period, and in the long run, will drop down to zero once the greenhouse gases characteristics reach its maximum for the low-income and lower middle-income countries. However, in highly developed countries, the level of greenhouse gases characteristics does not matter to global tourism. Global tourism is not dependent on how high or low the greenhouse gases characteristics of highly developed countries are, which implies that other factors have influenced the global tourism of these countries even if the greenhouse gases characteristics are high. It is suggested that the governments in low income and lower-middle-income countries which significantly rely on tourism should be responsive by inventing and adopting green technology, promoting eco-friendly operation and adopting sustainable tourism to protect the environment and promote renewable energy which will help lessen the greenhouse gases emitted by various production industries.

Improving Electricity Production in Solar Chimney Power Plants with Sloping Ground Design: An Extensive CFD Research

Unlike other solar energy systems, solar chimney power plants (SCPPs) allow power output even when there is no sun. SCPPs are promising with their simple structure and 24-hour electricity production potential. Massive pressure tower in the system maintains continuous energy generation irrespective of climatic conditions. Solar energy harnessed by the huge collector area is transmitted to the gorund material for sensible or latent heat storage purpose, and this stored energy during daytime yields to enhanced thermal and buoyant effects even after sunset. SCPPs are also in the centre of interest owing to their eco-friendly operation not causing any CO2 emission. Design aspects in SCPPs are widely studied numerically by researchers. However, geometric design factors are merely analysed for collector and chimney, and very few attempts are done for the ground design. In the present work, a new design for ground is proposed in order to improve the energy stored in the ground material, and the upward movement of the air flow in the system from collector to chimney by changing the ground geometry. The upward movement of the air under the collector is enhanced with the new design created by inclining the ground at a distance of 21 m from the chimney inlet to a certain distance from the collector inlet. ANSYS WORKBENCH based CFD analysis is carried out based on the geometric dimensions of the Manzanares pilot plant. Analyses are based on a 90° 3D CFD model for the purpose of time saving in iterations. The CFD model is supported by RNG k-? turbulence and DO (discrete ordinates) solar ray tracing models. After CFD results are verified with the experimental data, simulations are repeated for different designs and the ideal design is achieved. It is observed that the maximum air flow velocity, which is 14.202 m/s on the horizontal ground for the reference case, is improved by 34.1% in the new design to 19.046 m/s. In addition, it is seen that the power output of the reference case (54.333 kW) is enhanced by 23.04% to 66.855 kW.

Joint Planning of Smart EV Charging Stations and DGs in Eco-Friendly Remote Hybrid Microgrids

This paper proposes an efficient planning algorithm for allocating smart electric vehicle (EV) charging stations in remote communities. The planning problem jointly allocates and sizes a set of distributed generators (DGs) along with the EV charging stations to balance the supply with the total demand of regular loads and EV charging. The planning algorithm specifies optimal locations and sizes of the EV charging stations and DG units that minimize two conflicting objectives: 1) deployment and operation costs and 2) associated green house gas emissions, while satisfying the microgrid technical constraints. This is achieved by iteratively solving a multi-objective mixed integer non-linear program. An outer sub-problem determines the locations and sizes of the DG units and charging stations using a non-dominated sorting genetic algorithm. Given the allocation and sizing decisions, an inner sub-problem ensures smart, reliable, and eco-friendly operation of the microgrid by solving a non-linear scheduling problem. The proposed algorithm results in a Pareto frontier that captures the tradeoff between the conflicting planning objectives. Simulation studies investigate the performance of the proposed planning algorithm in order to obtain a compromise planning solution.

Analysis of Energy Storage Implementation on Dynamically Positioned Vessels

Blackout prevention on dynamically positioned vessels during closed bus bar operation, which allows more efficient and eco-friendly operation of main diesel generators, is the subject of numerous studies. Developed solutions rely mostly on the ability of propulsion frequency converters to limit the power flow from the grid to propulsion motors almost instantly, which reduces available torque until the power system is fully restored after failure. In this paper, a different approach is presented where large scale energy storage is used to take part of the load during the time interval from failure of one of the generators until the synchronization and loading of a stand-by generator. In order to analyze power system behavior during the worst case fault scenario and peak power situations, and to determine the required parameters of the energy storage system, a dynamic simulation model of a ship electrical power system is used. It is concluded that implementation of large scale energy storage can increase the stability and reliability of a vessel’s electrical power system without the need for the reduction of propulsion power during a fault. Based on parameters obtained from simulations, existing energy storage systems were evaluated, and the possibility of their implementation in the maritime transportation sector was considered. Finally, an evaluation model of energy storage implementation cost-effectiveness was presented.