Full Load Research Articles

Fully Soft-Switched Buck–Boost Bridgeless PFC Converters With Single-Magnetic Core

This paper proposes new fully soft switched bridgeless buck-boost power factor correction converters using single magnetic core with capability of realizing positive or negative output voltages. Full ZVS operation is provided for the main switches independent of the load and grid voltage variations. Also, the proposed converters have common ground and single ended output which increase power density and alleviates common mode noise. The proposed converters operate under discontinuous conduction mode (DCM) to shape the input current inherently. A 120W, 100kHz laboratory prototype with negative output voltage is implemented to verify the theoretical analysis and the effectiveness of the proposed topologies. The results demonstrate efficiency of 96.2% and total harmonic distortion (THD) of 4% at full load condition.

THE SIGNIFICANCE OF PROPER COOLING TOWER WATER TREATMENT: A CASE STUDY

This paper presents the result of a study of the effect of cooling tower system in terms of performance and cost of maintenance. The study was conducted in a two-storey shopping complex building. Observation on site was held to obtain data on full load amp (FLA) and chilled water temperature (CWT) before and after servicing cooling tower unit. Energy of cooling tower were evaluated by analysis of FLA and CWT in percentage value. The condition on the system and component were also observed to differentiate the condition before and after treatment. The result obtained showed that cooling system performance after the treatment was increased.

Optimal management of full train load services in the shunting yard: A comprehensive study on Shunt-In Shunt-Out policies

A key aim of the European Union is to double freight rail traffic by 2050 in order to reduce pollution emissions and alleviate congestion by shifting traffic from roads to rail networks. To accomplish this objective, it is crucial to minimize emissions and high costs associated with shunting yard operations while maintaining an acceptable level of service. This research paper introduces a new MINLP model that optimizes the shunt-in and shunt-out (SISO) operations of wagons in a shunting yard that handles full train load services. Additionally, an efficient Multi-Objective Dijkstra Algorithm (MDA) is proposed to handle simultaneous shunt-out operations in a multi-train scenario. The MINLP model takes a mesoscopic approach, aiming to minimize the number of SISO operations while satisfying strategic and tactical objectives such as wagon fleet size, operational costs, and shunting locomotive emissions. Several versions of the mathematical model are described, each employing different Shunt-In (SI) policies with varying criteria for wagon selection and strong goal orientation. The Multi-Objective Dijkstra Algorithm determines the Multi-Objective Shortest Path between mandatory shunts, considering both the time required for shunting and clustering costs. It provides information on the clusters of wagons that need to be shunted out. To assess the effectiveness of the MINLP model, real train timetables for freight trains in the Bettembourg Eurohub Sud Terminal (Luxembourg) are used, and various KPIs related to tactical and strategic objectives are evaluated. Furthermore, the performance of the Multi-Objective Dijkstra Algorithm is compared to the Shunt-Out sub-model, considering average computation time and solution quality in relation to the MINLP model. The computational results demonstrate that the criteria for wagon selection have a significant impact on the analyzed KPIs.

Studies on semi-cylindrical solar tunnel dryer for drying wastewater sludge

Drying plays an important process for wastewater sludge management, as it can minimise the volume of wastewater sludge before disposal, and consequently the cost of storage, handling and transport. In this study, the wastewater sludge was dried by using a solar tunnel greenhouse drying system. The performance of the dryer for drying wastewater sludge has been analyzed through no load and full load test. The three full load drying tests recorded that the temperature inside the tunnel dryer fluctuated around 55±5°C; while the no load drying test, the temperature of the drying tunnel maintained within 60±5°C; as compared to the ambient temperature of 30±5°C. The average moisture content of solar dried sludge decreased from 88.69 - 90.84% to 7.78 – 13.30% in the mixing conditions and 14.78 – 19.52% in the non-mixing conditions, in 5 days. The study suggests that the semi-cylindrical solar tunnel dryer of wastewater sludge has given satisfactory results within five days.

Performance, Combustion, and Emission analysis of diesel engine fuelled with pyrolysis oil blends and n-propyl alcohol-RSM optimization and ML modelling

This experimental work focuses on testing the diesel engine by the replacement of pyrolysis oil extracted from different waste plastics. The novelty of this work is testing the engine performance, combustion, and emission study with the following proportions D90WPO7NP3, D80WPO15NP5, D70WPO23NP7, WPO100, and D100. The pyrolysis oil is extracted from the mixed waste plastics with calcium bentonite as a catalyst and n-propyl alcohol is used as an additive for better igniting developer. From the results, it is found that the performance parameters such as BTE are found to increase in efficiency by 2.2% for the fuel D90WPO7NP3 and decrease in BSFC by 3.1% for the same fuel compared to pure diesel. It is also noticed that the emission properties such as CO2, CO, HC, and O2 content decreased in the order of 5.49%, and 6.2%. 39.2 and 12.5 % as compared to pure diesel. However, there is a slight increase in emissions of NOX due to the presence of uncontrolled enriched constituents in the pyrolysis oil; the increase in NOx emissions is found to be 16.2% compared to diesel fuel at full load conditions. The ML and RSM techniques using ANOVA techniques are adopted to find the least accuracy of data. This shows that the model fits the data well. The linear regression model explains 93.6% of the variation in BTE during training and has 95.9% prediction power. Linear Regression showed good predictive skills, acquiring a high R2 value of 0.985. It is concluded that pyrolysis oil with n-propyl alcohol as an additive gives a better substitute in the field of automobile applications.

Prediksi Daya Listrik Pada Pembangkit Listrik Siklus Gabungan Berdasarkan Kondisi Lingkungan Menggunakan Metode Machine Learning

The utilization of machine learning methods in energy simulation enables the optimization of energy use and improves energy efficiency. In this research, the modeling of predicting power output was conducted under full load conditions in a Combined Cycle Power Plant (CCPP) based on the surrounding environmental conditions. Historical data of CCPP operation were used to model and predict power output under various environmental conditions. In this study, four machine learning algorithms, namely Linear Regression (LR), Decision Tree (DT), Random Forest (RF), and Artificial Neural Network (ANN), were compared and evaluated for their performance. The evaluation metrics used to measure the model performance were Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R-Squared. The research results indicate that the Random Forest (RF) model achieved the best performance compared to other models with MAE of 2.314, RMSE of 3.372, and R-squared of 0.961. Additionally, the RF model also performed the best compared to other models in external testing with new data, where RF obtained values of MAE 2.579, RMSE 3.315, and R-squared 0.957. These results are consistent with the previous testing, indicating that RF has stable and reliable performance in predicting larger and more diverse datasets. This research contributes to understanding the potential application of machine learning in the power generation industry, especially in CCPP.

The First Results of a Full Loading Dose of Brolucizumab in the Treatment of DME

The aim of the study was to evaluate the efficacy and safety of brolucizumab in the Russian population of patients with diabetic macular edema. Patients and methods: 41 patients (29 women and 12 men) with diabetic retinopathy and diabetic macular edema of comparable age were included in the study. The patients were divided into 2 groups depending on the previous DME treatment. The first group included 24 patients (24 eyes) who had not previously received treatment: 9 men and 15 women, the average age of patients was 62.9 ± 9.3 years, the average best-corrected visual acuity was 0.40 ± 0.23, CTS 332 ± 87 microns, MV 9.65 ± 1.2 mm3. There were 17 patients (17 eyes) in the second group, they had previously received other antiangiogenic drugs, but retained the activity of the disease against the background of the treatment (1 man and 16 women), the average age of patients was 60.6 ± 8.3 years, the average best-corrected visual acuity was 0.40 ± 0.27, CTS 351.6 ± 149.0 microns, MV 9.3 ± 1.8 mm3. All patients received at least 5 intravitreal injections of brolucizumab (205 injections in total) at intervals of 6 weeks. The control examination was carried out 6 weeks after the last injection and a month after the fifth injection. The best-corrected visual acuity, intraocular pressure, central retinal thickness (CTS), macular volume (MV) were evaluated according to optical coherence tomography. Results. In the first group, a statistically significant increase in the best-corrected visual acuity was revealed from 0.40 ± 0.23 to 0.575 ± 0.27 (p = 0.05), the indicators of CTS and MV statistically significantly decreased. In the second group, only a decrease in CTS was detected, while the indicators of BCVA and MV did not show statistically significant changes. Conclusion. Patients with DME, who were treated with brolucizumab and who had not previously received treatment with other drugs, showed an improvement in anatomical and functional parameters, patients, who retained the activity of the disease against the background of the treatment, showed a slight decrease in the activity of the disease.

On the Demonstration of a Humid Combustion System Performing Flexible Fuel-Switch From Pure Hydrogen to Natural Gas With Ultra-Low NOx Emissions

Abstract To fight global warming the European Union formulated the objective of completely decarbonizing the energy sector, stimulating the advent of unconventional fuels and the adaption of the corresponding energy infrastructure. The decarbonization strategy identified hydrogen to play a key role as an energy storage medium, making systems capable of pure hydrogen operation essential. This requirement can be fulfilled with humid power cycles which offer additional advantages such as highly efficient and fuel-flexible operation with low emissions. As an integral part of such a cycle, a humid combustion system was presented previously showing promising results with respect to complete combustion with low emissions for a variety of fuels. The current work introduces an upgraded version of that combustion system. The new Double Swirler system is capable of stable and safe combustion of low calorific value biosyngas surrogate, hydrogen, and natural gas, from dry to steam-rich conditions within the required pressure drops. The inclusion of dry operation of the system can benefit the startup procedure of the humid cycle. The combustor's fuel switching performance is demonstrated by a fast fuel switch at full load from pure hydrogen to pure natural gas and vice versa, while maintaining a stable performance with low NOx-emissions at otherwise constant operation parameters.

Study on Through-Flow Characteristics of a Diesel Two-Stage Supercharged Centrifugal Compressor under Variable-Altitude and Multiple Operating Conditions

Understanding the influence of environmental boundary parameters on the through-flow characteristics of two-stage supercharged centrifugal compressors is the key to maximizing the power recovery potential of diesel engines at high altitudes. In this paper, the influence of the compressor through-flow characteristics on the full-load thermal cycle performance of a diesel engine under variable altitude is studied by means of tests and simulation. The results show that with the increase in altitude, the range of stable work flow decreases, and the pressure ratio of the plugging point changes greatly with altitude. The efficiency of the compressor with the same mass flow point decreases, and the highest efficiency point moves in the direction of the small flow range. With the goal of maximizing the torque of the diesel engine under full load and low speed, the key geometric parameters of the variable-altitude through-flow characteristics of the two-stage supercharged compressor were optimized as follows: at the altitudes of 0 m, 2500 m, and 5500 m, the diesel engine torque increased by 5.89%, 3.78%, and 2.18%, respectively. Based on the optimization method of the compressor through-flow design, a new direction is provided to break through the research on the independent limitation of the diesel engine thermal cycle performance optimization and compressor flow control.

Line-Start Permanent Magnet Synchronous Motor Supplied with Voltage Containing Negative-Sequence Subharmonics

In some power systems, the voltage waveform contains frequency components less than fundamental, called subharmonics or subsynchronous interharmonics. Voltage subharmonics can be both positive- and negative-sequence, independent of their frequency (order). Subharmonics exert harmful effects on sundry electrical equipment, especially on rotating machinery; they cause various noxious phenomena, such as a local saturation of the magnetic circuit, increases in power losses and windings temperature, and torque pulsations leading to vibration of unacceptable severity. Notably, previous works reported excessive vibration of rotating machinery only under no-load, while under full load, rather moderate vibration occurred. This study deals with vibration analysis of a line-start permanent magnet synchronous motor (LSPMSM) supplied with the voltage containing negative-sentence subharmonics. Experimental investigations were conducted for a 3 kW, four-pole production LSPMSM for subharmonics of various values and frequencies. Voltage subharmonics of values significantly less than reported in real power systems were found to cause unacceptable vibration, especially under full load.

Production of biofuel from AD digestate waste and their combustion characteristics in a low-speed diesel engine

Anaerobic digestion biogas plants generate large amounts of digestate that cannot always be valorised as fertilizer. This study proposes an alternative use through pyrolysis of the digestate for the production of liquid fuels for compression ignition engines. The digestate pyrolysis oil (DPO) and two types of biodiesel were produced and mixed with different alcohols. A total of five blends of DPO, biodiesel and alcohol were prepared and characterized, showing that their acidity and viscosity were higher than for pure diesel, and their heating value was lower. Blends containing 60 % biodiesel, 20 % DPO, and 20 % butanol were then tested in an engine, showing that the maximum in-cylinder pressure and heat release rate were 4.6 % and 3 % lower, respectively, compared to diesel, and the engine thermal efficiency at full load was 6–8% lower. The nitric oxide and smoke emissions were 7 % and 40 % lower, respectively, but the carbon dioxide emissions were 7–10 % higher than with diesel. The blends showed retarded start of combustion by 1.5° crank angle, which delays the ignition by about 6.4 %. This study concludes that blends can be used as a fuel for agriculture and marine diesel engines, although their viscosity should be reduced by improving the pyrolysis conditions.

Analysis and small‐signal modelling technique for support bus DC‐link of front‐end coupling inductance high step‐up single switch boost converter in low voltage renewable source

AbstractThis study proposes a non‐isolated DC converter, which is connected in series with an inverter, with a high output voltage conversion ratio for application in electricity generation systems to upgrade low‐voltage to high‐voltage DC. The topology of the proposed converter is based on a boost converter, which has the limitation of a low voltage conversion ratio. The converter is developed and connected using a coupling inductance technique by adding a second winding L2 coupled with the prototype winding and diode D2. This technique increases the voltage ratio via the ratio operator (N) of both the induction coils by operating a single switch at a constant frequency of 60 kHz. The working principle of the proposed converter is based on pulse width modulation with a duty cycle ≤40%. When the converter receives a low voltage DC input of 36 V, it converts the input to a high output voltage of 325 V at an output power 125 W, showing a circuit efficiency of 92.48% at full load. The synthesis and design of the controller include a linear approach to represent the parameters using the small signal methodology, which is employed to establish a transfer function. Furthermore, the proposed converter is capable of effectively regulating the output voltage, even when subjected to variations in the output load by employing a proportional–integral control mechanism. The close loop results obtained from simulations and practical implementation verified the proposed circuit design, as both results agreed with the theoretical analysis.

Optimizing dialysis water treatment based on medical planning requirements

This paper introduces a new approach to improving hemodialysis and peritoneal dialysis processes. This maintains compatibility between the water treatment unit and active dialysis machines. Identification of different deviations in the patient’s requirements to classify the suitable flow rate (FR) of the pure water can be created through an Adaptive Neuro-Fuzzy Inference System (ANFIS). Four types of categories are classified: quarter load, half load, three-quarter load, and full load. This includes two main steps: identifying the dialysis categories with patients and measuring the suitable FR for each category. The effective FR of water was computed to indicate how the number of pumps rose as the number of patients treated within the dialysis unit increased. The introduced prediction method was tested against artificial neural networks to predict alum doses (ANN-AD) method, artificial intelligence as a combinatorial optimization strategy (AN-COS) using peach-palm waste in a solid-state fermentation environment, expert system applications (ESA) in chronic kidney disease management (MDSSs), prescription optimization for automated peritoneal dialysis (BCPH). In this work, pumping system parameter estimation was utilized to assess the performance of the introduced systems based on input voltage, input current, rotor speed, and electromagnetic torque waveforms of the pumping drive. This method uses the ANFIS algorithm to construct a high-performance pumping system to evaluate and predict the flow rate of dialysis machines based on input–output estimates. The flow rate values for each patient in critical care units can be controlled by the presented algorithm according to the time of dialysis. A good predictive model based on integrating the experience and decision making of medical planners was implemented. The proposed method not only improves accuracy but also saves time in the dialysis unit. The presented fuzzy classifier uses the ratio of the number of predicted true positives and false positives to the total number of anticipated positives. The simulation results show that the proposed technique can be successfully used to classify the suitable FR of the water according to the hemodialysis load. One of the advantages of the presented technique is the ability to predict the value of FR in real time with reliability, low computational complexity, and a high accuracy of 98.01%, which simplifies the dialysis process for many patients while at the same time leading to improved performance of hemodialysis. The presented method can be implanted in online FR estimation and analysis hardware for hemodialysis, is easy to calculate and run in real time, minimizes hemodialysis costs, and saves run time.

Determination of effects of some alcohol blends on performance, emission, mechanical vibration and noise in diesel engines

The use of alcohol-derived fuels produced from renewable resources is an effective method to reduce dependence on petroleum. However, alcohols can improve the combustion process by changing the fuel chemistry. In this way, performance, emission, mechanical vibration and noise values can be improved in diesel engines. In this study; New fuel forms (D90E10, D90IB10, D80E10IB10, D77.5E10IB10DEE2.5, 75E10IB10DEE5) were formed by mixing ethanol, isobutanol and diethyl ether alcohols with diesel fuel in certain proportions. The fuels generated was used in experiments. The studies were conducted with four different loads (%25, 50, 75, and 100) at a constant speed (2800 rpm). The optimum fuel mixture was determined by examining the engine performance, exhaust emissions, mechanical vibrations and noise data obtained in the experiments. When the most important data output of the test results is evaluated; In tests with D75E10IB10DEE5 fuel, it was determined that smoke emissions were reduced by 24.6% and mechanical vibrations by 14.2% compared to standard diesel fuel at full load.

Effect of compression ratio and injection timing on the performance of microalgae‐based biodiesel blend

AbstractThe manuscript addressed experimental work related to microalgae‐based biodiesel blend B20, that is, 20% algae biodiesel and 80% diesel, as an alternative fuel as a possible source to power diesel engines. The physiochemical characteristics of this B20 blend were almost in line with diesel fuel as per American Society for Testing and Material standards. Coupled experimentation related to variations in compression ratio (CR) 17, 19, and 21 and fuel injection timing (IT) of 21°, 23°, and 25° before top dead center (bTDC) with load variations noted on diesel engines. We observed that, at full load, CR21 and 23° bTDC fuel IT, the brake thermal efficiency parameters rose significantly, whereas brake‐specific fuel consumption, and combusted flue gas temperatures also plummeted. The CO, HC, and smoke opacity emission for the B20 blend at CR21 and FIT23 has decreased by 30.52%, 33.33%, and 32.96%, respectively. At full load conditions, NOx emission for B20 biodiesel at CR21 was increased compared with the standard setting and compared with diesel it was increased by 6.46%.

Energy, Exergy, and Emission Analysis of Biofuels in Compression Ignition Engine with Camphor Oil as Premixing Fuel

This article aims to study the impact of camphor oil premixing with intake air on compression ignition (CI) engine characteristics powered with jatropha oil and cottonseed oil. The experiment is conducted on the direct injection compression engine attached to the premixing setup. The investigation reveals that premixing of camphor oil with cottonseed oil and jatropha oil escalates the thermal brake efficiency to 35.02% and 33.62% and brings down the brake‐specific energy consumption to 10.27 and 10.70 kJ kWh−1. At all loading conditions, the premixing of camphor oil and the rise of camphor oil in premixing proportions increase the volumetric efficiency and cut the exhaust gas temperature. 20% premixing of camphor oil with cottonseed oil and jatropha oil drops the smoke opacity emissions by 22.23% and 11.86% and NO emission by 23.27% and 14.59%, respectively, at full load conditions. Further, it shows a 27.60% and 21.14% hike in CO emissions and a 31.34% and 31.87% hike in HC emissions at full load conditions. The in‐cylinder pressure, heat release rate, and mean gas temperature increase with increasing the energy share of camphor oil in premixing. Overall, the premixing of camphor oil shows better CI engine attributes except HC and CO emissions.

Impact of backtracking strategies on techno-economics of horizontal single-axis tracking solar photovoltaic power plants

Optimisation of horizontal single-axis tracking solar photovoltaic power plants is important for its optimal application. Commonly, standard backtracking has been applied to avoid mutual shading and improve the full load hours and levelised cost of electricity; however, this approach is not always the best solution for state-of-the-art modules with half cell technology. Backtracking has not yet been studied for different test sites with different solar and climatic conditions. This study aims to improve the knowledge on the techno-economic performance of horizontal single-axis tracking systems with half cell modules applying different backtracking strategies in full hourly resolution for nine test sites globally and varying row spacing. In addition to the standard backtracking algorithm, an advanced backtracking algorithm that varies the tracking angle only if the irradiance can be improved, and an advanced sophisticated backtracking algorithm simulating the irradiance for all possible tracking angles, are studied. The results confirm that standard backtracking is only superior for specific conditions. Compared to no backtracking, standard backtracking shows up to ca. 9% higher levelised cost of electricity due to lower full load hours. Advanced backtracking can lower the levelised cost of electricity by up to 9% and advanced sophisticated backtracking by up to 12%, due to improved full load hours. In general, results are similar and comparable for all test sites studied. This study highlights the importance of backtracking for optimised future horizontal single-axis tracking system planning.

A simulation study of single-vendor, single and multiple-manufacturers supply chain system, with stochastic demand and two distribution policies

This paper addresses the long-standing stochastic single-vendor, multi-manufacturer inventory control problem, using simulation optimization. It is assumed that Manufacturers producing similar goods experience very high random demand; hence, safety stock of raw materials is held in reserve in their warehouses. The vendor supplying this raw material (principal ingredients) as a policy restricts shipments to multiples of full truck load. Thus, it is necessary to take replenishment decision and coordinate delivery among these manufacturers. To solve this problem, we modeled the single vendor, single manufacturer version of the problem (AlDurgam et al., 2017) using simulation optimization techniques, which was validated numerically using parameters and results from AlDurgam et al. (2017). The simulation model was modified systematically to relax the single manufacturer assumption under two distribution policies namely, joint reorder point and vendor managed inventory. These policies were evidently modeled with stringent conditions in literature. A numerical example was provided to compare the performances of the two proposed policies, and the VMI policy was found to performed better in terms of financial savings. Lastly, we investigate the robustness of the famous continuous review (Q, R) inventory policy which is widely used in the mathematical modeling of this problem, against the common cycle assumption. The coefficient of variation is thus suggested as a judgment criterion of when to embrace simulation modeling ahead of other modeling techniques.

Experimental Assessment of Genset Performance for PCCI-DI Combustion Engine

Applying the PCCI-DI combustion concept which can yield low emissions is tried for vehicular applications. However, much work has not been carried out on the genset engine which is a constant speed application. The PCCI can be achieved by various methods like port injection, late direct injection, early direct injection, and multiple direct injections to name a few. However in this case, it is achieved using the port injection. The two different port injection quantities are tried out. The first is with 3 ms pulse and the other with 5 ms pulse of port injection. In this study, PCCI-DI engine is assembled with the alternator to form a genset. The genset is tested for assessing its behavior in real-world conditions. The main trials to simulate the realworld condition are the load throw-on and load throw-off trials. The extreme case of these trials is to load the engine from no load to full load during the throw-on trials and reverse in throw-off trials. The results indicate the best performance in the case of pure DI combustion. With the use of port injection, the genset performance decorates. This is due to the fuel being injected in the port and it takes a finite time for the reaction to sudden loading and de-loading of the engine. The higher the amount of port fuel injection the higher the deterioration in response is observed. The result gives the actual performance and the response in all three combustion configurations. All three cases met the ISO 8528-5 G3 class requirements.

Impact of thermal swing piston top land coatings on gasoline engine performance and raw emissions

Upcoming legislations aim to significantly reduce carbon dioxide and hydrocarbon emissions compared to current regulations. Accordingly, options have to be evaluated to not only convert the raw emissions in a catalytic converter, but also to reduce the raw emissions from the combustion process in the first place. Therefore, thermal piston top land coatings, which lead to an oscillating piston surface temperature were investigated on a single cylinder research engine using a gasoline RON95E10 fuel. Measurements were conducted at a compression ratio of 12.2 and a long Miller intake event. In this manuscript the results achieved with yttria stabilized zirconia in comparison to an uncoated piston are displayed. Significant effects of the coatings on the indicated efficiency could be observed mainly at low engine speeds and loads due to the high share of fuel energy in the wall heat losses and incomplete combustion. At these operating points, the reduction of wall heat losses can almost be fully transferred into indicated efficiency, leading to an increase in indicated efficiency of 6.3% by the yttria stabilized zirconia coating. At higher engine speeds and loads, the advantage in indicated efficiency vanishes and a decrease of 0.5% can be observed. Near full load operation the indicated efficiency slightly lower. However, the effects of a thermal swing coating on combustion efficiency and wall heat losses strongly depend on the operation conditions.