The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life....The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life.Polyurethane(PU)-based materials have gained attention as promising candidates for supercapacitor electrodes,due to their flexibility,mechanical robustness,and tunable properties.It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms.Instead,PU serves as a flexible scaffold,a binder,or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment.Thus,the term'PU-based'in this review refers to PU-supported or PU-derived composites,where PU enables structural or functional integration of active electrode Materi-als.Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm^(2)with capacitance retention of 92%over 5,000 cycles.Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg,reflecting their potential for high-performance energy storage applications.Despite these advantages,challenges,such as low intrinsic conductivity and the environmental impact of traditional synthesis methods,limit their widespread adoption.Conventional PU composites often incorporate conductive additives like carbon materi-als,metal oxides,or conductive polymers to enhance their electrochemical performance,yet these approaches may involve non-renewable or toxic components.Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations.This includes using renewable resources,environmentally friendly process-ing techniques,and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies.This review highlights current trends in developing eco-friendly supercapacitor materials,addressing key challenges such as limited conductivity and complex processing.It uniquely integrates green chemistry principles with advances in polyurethane composites,emphasizing sustainable feedstocks,heteroatom doping,and functional nanomateri-als.By combining these aspects,this review provides a comprehensive perspective not fully covered in existing literature.展开更多
In order to achieve a highly accurate estimation of solar energy resource potential,a novel hybrid ensemble-learning approach,hybridizing Advanced Squirrel-Search Optimization Algorithm(ASSOA)and support vector regres...In order to achieve a highly accurate estimation of solar energy resource potential,a novel hybrid ensemble-learning approach,hybridizing Advanced Squirrel-Search Optimization Algorithm(ASSOA)and support vector regression,is utilized to estimate the hourly tilted solar irradiation for selected arid regions in Algeria.Long-term measured meteorological data,including mean-air temperature,relative humidity,wind speed,alongside global horizontal irradiation and extra-terrestrial horizontal irradiance,were obtained for the two cities of Tamanrasset-and-Adrar for two years.Five computational algorithms were considered and analyzed for the suitability of estimation.Further two new algorithms,namely Average Ensemble and Ensemble using support vector regression were developed using the hybridization approach.The accuracy of the developed models was analyzed in terms of five statistical error metrics,as well as theWilcoxon rank-sum and ANOVA test.Among the previously selected algorithms,K Neighbors Regressor and support vector regression exhibited good performances.However,the newly proposed ensemble algorithms exhibited even better performance.The proposed model showed relative root mean square errors lower than 1.448%and correlation coefficients higher than 0.999.This was further verified by benchmarking the new ensemble against several popular swarm intelligence algorithms.It is concluded that the proposed algorithms are far superior to the commonly adopted ones.展开更多
Solar humidification-dehumidification desalination technology has been reviewed in detail in this paper. This review would also throw light on the scope for further research and recommendations in active distillation ...Solar humidification-dehumidification desalination technology has been reviewed in detail in this paper. This review would also throw light on the scope for further research and recommendations in active distillation system by humidification and dehumidification (HDH). Also in this article, a review has been done on different types of (HDH) systems. Thermal modeling was done for various types of humidification and dehumidification(HDH) distillation system. From the present review, it is found that the humidification-dehumidification desalination process HDH will be a suitable choice for fresh water production when the demand is decentralized. HDH is a low temperature process where total required thermal energy can be obtained from solar energy. Capacity of HDH units is between that produced by conventional methods and solar stills. Moreover, HDH is distinguished by simple operation and maintenance. Also from the present condensed review, it was observed that an increase in evaporator and condenser surface areas significantly improves system productivity. But prior to implementing any techniques in design improvement, it is necessary to optimize the MEH unit by optimizing its component size to understand the effect of feed water and air flow rates. Although a fair amount of simulation studies have been conducted in the past, further design simulation is required to fully understand the complicated effects of air and water flow rates, the optimum size of individual components or modules of the unit and to generate a comprehensive model for the system.展开更多
Biogas is a renewable and clean energy source that plays an important role in the current environment of lowcarbon transition.If high-content CO_(2) in biogas can be separated,transformed,and utilized,it not only real...Biogas is a renewable and clean energy source that plays an important role in the current environment of lowcarbon transition.If high-content CO_(2) in biogas can be separated,transformed,and utilized,it not only realizes high-value utilization of biogas but also promotes carbon reduction in the biogas field.To improve the combustion stability of biogas,an inhomogeneous,partially premixed stratified(IPPS)combustion model was adopted in this study.The thermal flame structure and stability were investigated for a wide range of mixture inhomogeneities,turbulence levels,CO_(2) concentrations,air-to-fuel velocity ratios,and combustion energies in a concentric flow slot burner(CFSB).A fine-wire thermocouple is used to resolve the thermal flame structure.The flame size was reduced by increasing the CO_(2) concentration and the flames became lighter blue.The flame temperature also decreased with increase in CO_(2) concentration.Flame stability was reduced by increasing the CO_(2) concentration.However,at a certain level of mixture inhomogeneity,the concentration of CO_(2) in the IPPS mode did not affect the stability.Accordingly,the IPPS mode of combustion should be suitable for the combustion and stabilization of biogas.This should support the design of highly stabilized biogas turbulent flames independent of CO_(2) concentration.The data show that the lower stability conditions are partially due to the change in fuel combustion energy,which is characterized by the Wobbe index(WI).In addition,at a certain level of mixture inhomogeneity,the effect of the WI on flame stability becomes dominant.展开更多
Solar stills are considered an effective method to solve the scarcity of drinkable water.However,it is still missing a way to forecast its production.Herein,it is proposed that a convenient forecasting model which jus...Solar stills are considered an effective method to solve the scarcity of drinkable water.However,it is still missing a way to forecast its production.Herein,it is proposed that a convenient forecasting model which just needs to input the conventional weather forecasting data.The model is established by using machine learning methods of random forest and optimized by Bayesian algorithm.The required data to train the model are obtained from daily measurements lasting9 months.To validate the accuracy model,the determination coefficients of two types of solar stills are calculated as 0.935and 0.929,respectively,which are much higher than the value of both multiple linear regression(0.767)and the traditional models(0.829 and 0.847).Moreover,by applying the model,we predicted the freshwater production of four cities in China.The predicted production is approved to be reliable by a high value of correlation(0.868)between the predicted production and the solar insolation.With the help of the forecasting model,it would greatly promote the global application of solar stills.展开更多
Hybrid<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family...Hybrid<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">chiller plants (HCPs)</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">using multiple chillers and different energy sources</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are highly recommended in several energy applications in non-residential buildings such as hospitals and hotels. Time of use and cooling load profiles are significant factors that should be carefully considered either in chiller plant design or in chiller sequencing operation. This article aims to present an operation planning of HCP which consists of both electric and non-electric chillers. Four operational strategies are proposed and solved to compare their coefficients of performance and economics of running costs. A typical hotel building located on the Nile river in Egypt is selected to perform the current thermal and economic case study. The total cooling load profile of this hotel building is 4000 refrigeration tonnage (TR), which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">simulated to optimize chiller sequence of operation and to select optimal design conditions of both numbers for electric and non-electric chillers used in HCP. The results of this comparative study for running cost are defined using various design configurations with different several chiller sequences available for each configuration. Then, the results of COPs, and operational running cost and initial cost are presented in this article also. The comparison aims to find the optimal design and operational sequencing for HCPs on thermal basis and economic analysis which were attached in this article. Recommendations and suggestions for future work are attached at the end of this article.</span></span></span>展开更多
Several media report highlight on that the pharmaceutical companies require ultra-low temperatures -80<span style="white-space:nowrap;">°</span>C to transport and store its COVID-19 vaccines...Several media report highlight on that the pharmaceutical companies require ultra-low temperatures -80<span style="white-space:nowrap;">°</span>C to transport and store its COVID-19 vaccines. This research presents the thermodynamic analysis on cascade refrigeration system (CRS) with several refrigerant pairs which are R32/R170, R123/R170, R134a/R170, R404A/R170, R407c/R170, R410/R170, and the hydrocarbon (HC) refrigerant pair Propane/Ethane, namely R290/R170. Besides, the results of R22/R170 pair, which is not recommended to be used due to phase out of R22 as per Montréal Protocol, are included as base case to compare the novel hydrocarbon pairs in CRS and the old trend of refrigerant pairs. Thermodynamic properties of all these pairs were investigated and compared under different intermediate temperature used in CRS heat exchanger, which thermally connected both the Low and High temperature cycles (LTC) and (HTC). By applying the first law of thermodynamics, the coefficients of performance (COPs) and the specific power consumptions (SPC) in kW/TR are presented and compared. In addition, by applying the second law of thermodynamics the exergetic efficiencies were estimated. The results reveal the promising opportunity of using the HC pair (R290/R170). The minimum SPC in kW/TR is recorded for the pair R123/R170. One the other hand, the highest exegetic efficiency values are observed to be 40%, 38%, and 35% for the pairs R123/R170, R290/R170, and R134/R170, respectively. This research concludes that the HC pair (R290/R170) is highly recommended for CRS applications either to transport the COVID-19 or store it in cold storage rooms in hospitals and clinics. All precautionary measures should be carefully applied in design and operation of HC pair (R290/R170) due to its flammability hazard.展开更多
In this study, an Artificial Neural Network (ANN) model to predict the pressure drop of turbulent flow of titanium dioxide-water (TiO2-water) is presented. Experimental measurements of TiO2-water under fully developed...In this study, an Artificial Neural Network (ANN) model to predict the pressure drop of turbulent flow of titanium dioxide-water (TiO2-water) is presented. Experimental measurements of TiO2-water under fully developed turbulent flow regime in pipe with different particle volumetric concentrations, nanoparticle diameters, nanofluid temperatures and Reynolds numbers have been used to construct the proposed ANN model. The ANN model was then tested by comparing the predicted results with the measured values at different experimental conditions. The predicted values of pressure drop agreed almost completely with the measured values.展开更多
This paper represents a review of the recent researches that investigate the behavior of the gas turbulent flow laden with solid particles. The significant parameters that influence the interactions between the both p...This paper represents a review of the recent researches that investigate the behavior of the gas turbulent flow laden with solid particles. The significant parameters that influence the interactions between the both phases, such as particle size, loading ratio and the gas velocity, have been extensively reviewed. Those parameters are presented in dimensionless numbers in which the applicability of studying its effect in terms of all circumstances of the gas turbulent channel flow at different condition is possible. The represented results show that the turbulence degree is proportional to the particle size. It was found that at the most flow conditions even at low mass ratio, the particle shape, density and size significantly alter the turbulence characteristics. However, the results demonstrate that the particle Reynolds number is a vital sign: the turbulence field becomes weaker if particle Reynolds number is lower than the critical limit and vies verse. The gas velocity has a strong effect on the particles settling along the channel flow and as a result, the pressure drop will be affected.展开更多
Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cr...Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5 × 18 mm2 and the other is triangular with dimension of 5 × 9 mm2. Four channels of each configuration have been etched on copper block of 40 mm width,30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002 - 0.005 m3/s, heating powers of 80 - 200 W and channel base temperatures of 48°C, 51°C, 55°C and 60°C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than trian- gular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ±10%. But for the heat transfer data, the deviation is about +30% to –60% for 1-D model, and –5% to –80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as with accuracy of ±20% for and compared with other literature correlations.展开更多
This research aims to present a simplified mathematical model to predict the performance of fire tube boilers, taking into account the necessity of knowing the components of exhaust gases and the extent of their compa...This research aims to present a simplified mathematical model to predict the performance of fire tube boilers, taking into account the necessity of knowing the components of exhaust gases and the extent of their compatibility with environmental laws and requirements. The model shown is for a horizontal, three-pass, wet-back fire tube boiler at steady-state, steady-flow operation. It is concluded from the applicability of the model for different boiler capacity ratings that the results are simplified and important for the boiler manufacturers to predict the performance and make the choice to modify the proposed design to achieve certain needs.展开更多
Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some pa...Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some parts of the globe,there is an imperative need to develop alternative ways to predict it.Therefore,the main objective of this study is to evaluate the performance of different hybrid data-driven techniques in predicting daily GSR in semi-arid regions,such as the majority of Spanish territory.Here,four ensemble-based hybrid models were developed by hybridizing Additive Regression(AR)with Random Forest(RF),Locally Weighted Linear Regression(LWLR),Random Subspace(RS),and M5P.The base algorithms of the developed models are scarcely applied in previous studies to predict solar radiation.The testing phase outcomes demonstrated that the ARRF models outperform all other hybrid models.The provided models were validated by statisticalmetrics,such as the correlation coefficient(R)and root mean square error(RMSE).The results proved that Scenario#6,utilizing extraterrestrial solar radiation,relative humidity,wind speed,and mean,maximum,and minimum ambient air temperatures as the model inputs,leads to the most accurate predictions among all scenarios(R=0.968–0.988 and RMSE=1.274–1.403 MJ/m^(2)・d).Also,Scenario#3 stood in the next rank of accuracy for predicting the solar radiation in both validating stations.The AD-RF model was the best predictive,followed by AD-RS and AD-LWLR.Hence,this study recommends new effective methods to predict GSR in semiarid regions.展开更多
In the present study, dynamic performance of single bed desiccant regeneration system has been investigated experimentally. The desiccant bed operates as an adsorber and then as a regenerator, intermittently. In the e...In the present study, dynamic performance of single bed desiccant regeneration system has been investigated experimentally. The desiccant bed operates as an adsorber and then as a regenerator, intermittently. In the experimental work of this investigation, Silica gel is used as a desiccant material. In the regeneration process, hot air from an air heater is blown through the bed using an air blower. The performance of desorption process at different conditions of flowing air is demonstrated. The experimental tests were carried out at different conditions of inlet air and initial bed parameters. Temperature and humidity of air at inlet and exit of the bed were measured. The obtained results showed that hot air with an inlet temperature ranging from 40°C to 75°C could release a notable amount of water from the desiccant bed. The relation between the studied parameters during the desorption processes is correlated. Results also show that the “Rehabilitation period” in desorption process should be eliminated to decrease the desorption time and it could be eliminated if the hot air mass flow rate is greater than 1.92 kg/hr per kg of silica gel.展开更多
Al-Baha region, located in Saudi Arabia, is one of the main tourism and leisure areas. The authority at Al-Baha Governorate plans to use clean and renewable energy in its tourism facilities. The importance of this stu...Al-Baha region, located in Saudi Arabia, is one of the main tourism and leisure areas. The authority at Al-Baha Governorate plans to use clean and renewable energy in its tourism facilities. The importance of this study is to assess the possibility of building a wind farm in Al-Baha and to select the best site for this purpose. This paper presents an analysis of long-term wind data for the annual and monthly variability in Al-Baha region of southwestern Saudi Arabia. Al-Baha region has an area of 9921 square kilometers and is divided into seven regions (groups) based on their similar measurements and wind speed values. The analysis used 40 years of annual and monthly wind speed data between 1981 and 2020. The analysis showed that Group III has the highest mean wind speed values in the northeastern part of the Al-Baha region, ranging from 5.4 m/s to 5.9 m/s at 50 m above the surface. Group VI (5.1 - 5.6 m/s) east of the Al-Baha area recorded the second-highest mean wind speed, while group V southwest of the Al-Baha area recorded lower values. The maximum wind speeds observed in Group III in January, February, March, and July were 6 m/s or higher. A frequency analysis ensures that 79% of the year’s wind speeds exceed 4 m/s at 50 m above the surface of the Group III site. Wind power was considered for 17 wind turbines of different sizes. The Soyut Wind 500 machine was found to produce maximum energy of 1420 MWh/year. The highest performance values for the Soyut Wind 500 machine occurred in winter and summer, while the calculated capacity factor values at a hub height of 50 m were 41% and 32%, respectively. The assessment concluded that generating electricity from wind at G III in the northeast of the Al-Baha region is a good decision.展开更多
The efficiency of solar desalination systems is often hindered by the intermittent nature of solar radiation,leading to thermal fluctuations and reduced freshwater yield.This study investigates the integration of flin...The efficiency of solar desalination systems is often hindered by the intermittent nature of solar radiation,leading to thermal fluctuations and reduced freshwater yield.This study investigates the integration of flint stones as a low-cost and effective thermal energy storage(TES)medium to enhance the productivity and efficiency of conical solar stills.A series of experimental analyses were conducted using flint stones of varying diameters(1,1.5,2,and 2.5 cm)to determine their impact on thermal regulation,evaporation rates,and freshwater production.The findings revealed that 2 cm flint stones exhibited the highest thermal storage capacity and energy retention,leading to a 40.18%increase in water yield(7.85 L/m^(2)/day)compared to the conventional system(5.6 L/m^(2)/day).Additionally,the system with 2 cm flint stones demonstrated a 119.62%improvement in overall efficiency,135%enhancement in exergy efficiency,and 195%increase in the exergy production factor over the baseline system.The integration of flint stones provided thermal stability by reducing heat loss,maintaining consistent basin water temperatures,and extending the evaporation process beyond peak sunlight hours.This improved the overall stability and continuity of distillation performance throughout the day.Quantitatively,the economic analysis indicated a shortened payback period of 19 days for the optimized system,compared to 27 days for the conventional system,making it a cost-effective and sustainable solution for water-scarce regions.This study is the first to optimize the size of natural flint stones as TES materials in conical solar stills,demonstrating their superior heat retention capacity and significant performance improvement in freshwater production and energy utilization.The results validate the synergy between optimized TES and conical geometry as a promising design strategy for sustainable and affordable solar desalination systems.These findings pave the way for more efficient,economically viable,and environmentally sustainable solar desalination systems to combat global water scarcity.展开更多
Proton exchange membrane electrolysis cell(PEMEC)is one of the most promising methods to produce hydrogen at high purity and low power consumption.In this study,a three-dimensional non-isothermal model is used to simu...Proton exchange membrane electrolysis cell(PEMEC)is one of the most promising methods to produce hydrogen at high purity and low power consumption.In this study,a three-dimensional non-isothermal model is used to simulate the cell performance of a typical PEMEC based on computational fluid dynamics(CFD)with the finite element method.Then,the model is used to investigate the distributions of current density,species concentration,and temperature at the membrane/catalyst(MEM/CL)interface.Also,the effects of operating conditions and design parameters on the polarization curve,specific electrical energy demand,and electrical cell efficiency are studied.The results show that the maximum distribution of current density,hydrogen concentration,oxygen concentration,and temperature occur beneath the core ribs and increase towards the channel outlet,while the maximum water concentration distribution happens under the channel and decreases towards the channel exit direction.The increase in gas diffusion layer(GDL)thickness reduces the uneven distribution of the contour at the MEM/CL interface.It is also found that increasing the operating temperature from 323 K to 363 K reduces the cell voltage and specific energy demand.The hydrogen ion diffusion degrades with increasing the cathode pressure,which increases the specific energy demand and reduces the electrical cell efficiency.Furthermore,increasing the thickness of the GDL and membrane rises the specific energy demand and lowers the electrical efficiency,but increasing GDL porosity reduces the specific electrical energy demand and improves the electrical cell efficiency;thus using a thin membrane and GDL is recommended.展开更多
The jet pump is an artificial lift employed when the reservoir pressure declines and the well deviation increases.The use of computer well models for optimizing the oil well output has proven to be a suc-cessful strat...The jet pump is an artificial lift employed when the reservoir pressure declines and the well deviation increases.The use of computer well models for optimizing the oil well output has proven to be a suc-cessful strategy,and has helped increasing the efficiency and production of numerous wells.The objective of this study was to use a production optimization technique that achieves some improve-ments,and recommend approaches toward increasing the oil well production.The effects of the motive fluid flow rate and pressure on the oil production rate were investigated to determine the optimal in-jection rate and pressure on the performance of the deep well water-oil axial jet-pump.Additionally,the effects of the well-head pressure,water cut,and roughness of tubing on oil production of this jet pump type were investigated.The results revealed that the impact on the oil lift performance is significant.The oil production increased by 19.43%,and the optimal economic value for the injection rate and pressure for the GA-1A well are 744.44 BFPD and 2722.22 psig,respectively.In summary,increasing the tubing roughness decreased the well's total liquid production.Thus,maintaining the well integrity is a very important factor because not doing so can lower the productivity by up to 20%-25%.展开更多
Increased power density in modern miniaturized electronics caused difficulty in keeping electronic performance effective.This challenge leads to the search for high-performance compact heat exchanger as one of the the...Increased power density in modern miniaturized electronics caused difficulty in keeping electronic performance effective.This challenge leads to the search for high-performance compact heat exchanger as one of the thermal management solutions.Conventionally manufactured heat exchangers had limitations that thwart the develop-ment of geometrically complex heat exchangers which are capable of exploiting topological aspects to enhance thermal performance.Subsequently,additive manufacturing(AM)is proposed as a powerful fabrication tech-nique for compact heat exchanger based on the mathematically known triply periodic minimal surfaces(TPMS).In this work,we present 3D compact crossflow heat exchanger computational fluid dynamics(CFD)modelling of geometrically complex structures based on TPMS using STARCCM+CFD platform.Moreover,CFD modelling is used to obtain new characteristics maps that relate heat transfer effectiveness(Ɛ)and number of transfer units for the proposed heat exchanger.The convection heat transfer coefficient,pressure drop,and inlet and outlet fluid temperature are all examined.展开更多
Biodiesel is derived from waste cooking oil (WCO) by transesterification. Methylester was prepared by mixing diesel and biodiesel oils as 20% by volume. Nano particles asTiO2, Al2O3 and CNTs were blended with biodiese...Biodiesel is derived from waste cooking oil (WCO) by transesterification. Methylester was prepared by mixing diesel and biodiesel oils as 20% by volume. Nano particles asTiO2, Al2O3 and CNTs were blended with biodiesel blend at different concentrations of 25,50, and 100 mg/l to enhance the physicochemical fuel characteristics to obtain clean and effi-cient combustion performance. An experimental setup was incorporated into a diesel engine toinvestigate the influence of these nano-materials on engine performance, exergy analysis, combustion characteristics and emissions using WCO biodiesel-diesel mixture. Enriching methylester mixture with 100 ppm titanium, alumina and CNTs (B20T100, B20A100 andB20C100) increased the thermal efficiency by 4%, 6% and 11.5%, respectively compared toB20. Biodiesel blending with nano additives B20T100, B20A100 and B20C100 decreasedthe emissions of CO (11%, 24% and 30%, respectively), HC (8%, 17% and 25%, respectively)and smoke (10%, 13% and 19%, respectively) compared to B20. However, the noticeable increase of NOx was estimated by 5%, 12% and 27% for B20T100, B20A100 and B20C100,respectively. Finally, the results showed the rise in peak cylinder pressure by 5%, 9% and 11% and increase in heat release rate by 4%, 8% and 13% for B20T100, B20A100 andB20C100, respectively. The fuel exergy of B20T100, B20A100 and B20C100 are lower thanbiodiesel blend B20 by 6.5%, 16% and 23% but the exergetic efficiency are increased by 7%,19% and 30% at full load about B20.展开更多
Extraction of biodiesel from waste cooking oil,jatropha,and corn oils is done by transesterification.Diesel and biodiesel were blended at 20%volume ratio to make methyl ester.At doses of 25,50,and 100 mg/l,carbon nano...Extraction of biodiesel from waste cooking oil,jatropha,and corn oils is done by transesterification.Diesel and biodiesel were blended at 20%volume ratio to make methyl ester.At doses of 25,50,and 100 mg/l,carbon nanotubes(CNTs)was mixed with biodiesel blend.The objective of the present research is to examine experimentally a diesel engine performance,combustion characteristics,exergy and emissions analyses with inclusion of nano additive to various methyl ester feedstocks.Methyl ester blend is enriched with CNTs as JB20C100,WB20C100 and CB20C100 where the improvements in thermal efficiency are raised about biodiesel mixture by 9%,13%and 15%,respectively.Addition of 100 ppm of CNTs to biodiesel blends achieves the greatest reductions in CO(14%,22%and 30%),HC(16%,20%and 25%),and smoke emissions(15%,19%and 23%)for JB20C100,WB20C100 and CB20C100,respectively.By comparing with B20,blending 100 ppm CNTs with JB20,CB20,and WB20 obtained the highest increases in cylinder pressure of 3%,5%,and 10%,as well as the highest increases in heat release of 4%,7%,and 11%,respectively.The downside of CNTs addition achieves a rise in NOx emissions by 10%,17%,and 22%for JB20C100,WB20C100,and CB20C100,respectively.Exergetic efficiency increases by 8%,19%,and 24%for B20T100,B20A100,and B20C100,respectively.Sustainability index improvements achieve 1.5%,5%and 6.5%,for B20T100,B20A100,and B20C100,respectively.WB20 with CNTs of 100 ppm is highly recommended for improving engine performance,combustion,and exergy characteristics with considerable emissions reduction.展开更多
基金Open access funding provided by The Science,Technology&Innovation Funding Authority(STDF)in cooperation with The Egyp-tian Knowledge Bank(EKB).
文摘The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life.Polyurethane(PU)-based materials have gained attention as promising candidates for supercapacitor electrodes,due to their flexibility,mechanical robustness,and tunable properties.It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms.Instead,PU serves as a flexible scaffold,a binder,or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment.Thus,the term'PU-based'in this review refers to PU-supported or PU-derived composites,where PU enables structural or functional integration of active electrode Materi-als.Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm^(2)with capacitance retention of 92%over 5,000 cycles.Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg,reflecting their potential for high-performance energy storage applications.Despite these advantages,challenges,such as low intrinsic conductivity and the environmental impact of traditional synthesis methods,limit their widespread adoption.Conventional PU composites often incorporate conductive additives like carbon materi-als,metal oxides,or conductive polymers to enhance their electrochemical performance,yet these approaches may involve non-renewable or toxic components.Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations.This includes using renewable resources,environmentally friendly process-ing techniques,and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies.This review highlights current trends in developing eco-friendly supercapacitor materials,addressing key challenges such as limited conductivity and complex processing.It uniquely integrates green chemistry principles with advances in polyurethane composites,emphasizing sustainable feedstocks,heteroatom doping,and functional nanomateri-als.By combining these aspects,this review provides a comprehensive perspective not fully covered in existing literature.
文摘In order to achieve a highly accurate estimation of solar energy resource potential,a novel hybrid ensemble-learning approach,hybridizing Advanced Squirrel-Search Optimization Algorithm(ASSOA)and support vector regression,is utilized to estimate the hourly tilted solar irradiation for selected arid regions in Algeria.Long-term measured meteorological data,including mean-air temperature,relative humidity,wind speed,alongside global horizontal irradiation and extra-terrestrial horizontal irradiance,were obtained for the two cities of Tamanrasset-and-Adrar for two years.Five computational algorithms were considered and analyzed for the suitability of estimation.Further two new algorithms,namely Average Ensemble and Ensemble using support vector regression were developed using the hybridization approach.The accuracy of the developed models was analyzed in terms of five statistical error metrics,as well as theWilcoxon rank-sum and ANOVA test.Among the previously selected algorithms,K Neighbors Regressor and support vector regression exhibited good performances.However,the newly proposed ensemble algorithms exhibited even better performance.The proposed model showed relative root mean square errors lower than 1.448%and correlation coefficients higher than 0.999.This was further verified by benchmarking the new ensemble against several popular swarm intelligence algorithms.It is concluded that the proposed algorithms are far superior to the commonly adopted ones.
文摘Solar humidification-dehumidification desalination technology has been reviewed in detail in this paper. This review would also throw light on the scope for further research and recommendations in active distillation system by humidification and dehumidification (HDH). Also in this article, a review has been done on different types of (HDH) systems. Thermal modeling was done for various types of humidification and dehumidification(HDH) distillation system. From the present review, it is found that the humidification-dehumidification desalination process HDH will be a suitable choice for fresh water production when the demand is decentralized. HDH is a low temperature process where total required thermal energy can be obtained from solar energy. Capacity of HDH units is between that produced by conventional methods and solar stills. Moreover, HDH is distinguished by simple operation and maintenance. Also from the present condensed review, it was observed that an increase in evaporator and condenser surface areas significantly improves system productivity. But prior to implementing any techniques in design improvement, it is necessary to optimize the MEH unit by optimizing its component size to understand the effect of feed water and air flow rates. Although a fair amount of simulation studies have been conducted in the past, further design simulation is required to fully understand the complicated effects of air and water flow rates, the optimum size of individual components or modules of the unit and to generate a comprehensive model for the system.
基金funded by the American University in Cairo research grants(Project number SSE-MENG-M.M.-FY18-FY19-FY20-RG(1-18)–2017-Nov-11-17-52-02).
文摘Biogas is a renewable and clean energy source that plays an important role in the current environment of lowcarbon transition.If high-content CO_(2) in biogas can be separated,transformed,and utilized,it not only realizes high-value utilization of biogas but also promotes carbon reduction in the biogas field.To improve the combustion stability of biogas,an inhomogeneous,partially premixed stratified(IPPS)combustion model was adopted in this study.The thermal flame structure and stability were investigated for a wide range of mixture inhomogeneities,turbulence levels,CO_(2) concentrations,air-to-fuel velocity ratios,and combustion energies in a concentric flow slot burner(CFSB).A fine-wire thermocouple is used to resolve the thermal flame structure.The flame size was reduced by increasing the CO_(2) concentration and the flames became lighter blue.The flame temperature also decreased with increase in CO_(2) concentration.Flame stability was reduced by increasing the CO_(2) concentration.However,at a certain level of mixture inhomogeneity,the concentration of CO_(2) in the IPPS mode did not affect the stability.Accordingly,the IPPS mode of combustion should be suitable for the combustion and stabilization of biogas.This should support the design of highly stabilized biogas turbulent flames independent of CO_(2) concentration.The data show that the lower stability conditions are partially due to the change in fuel combustion energy,which is characterized by the Wobbe index(WI).In addition,at a certain level of mixture inhomogeneity,the effect of the WI on flame stability becomes dominant.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFE0127800)the Science,Technology&Innovation Funding Authority(STIFA),Egypt grant(Grant No.40517)+1 种基金China Postdoctoral Science Foundation(Grant No.2020M682411)the Fundamental Research Funds for the Central Universities(Grant No.2019kfy RCPY045)。
文摘Solar stills are considered an effective method to solve the scarcity of drinkable water.However,it is still missing a way to forecast its production.Herein,it is proposed that a convenient forecasting model which just needs to input the conventional weather forecasting data.The model is established by using machine learning methods of random forest and optimized by Bayesian algorithm.The required data to train the model are obtained from daily measurements lasting9 months.To validate the accuracy model,the determination coefficients of two types of solar stills are calculated as 0.935and 0.929,respectively,which are much higher than the value of both multiple linear regression(0.767)and the traditional models(0.829 and 0.847).Moreover,by applying the model,we predicted the freshwater production of four cities in China.The predicted production is approved to be reliable by a high value of correlation(0.868)between the predicted production and the solar insolation.With the help of the forecasting model,it would greatly promote the global application of solar stills.
文摘Hybrid<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">chiller plants (HCPs)</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">using multiple chillers and different energy sources</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are highly recommended in several energy applications in non-residential buildings such as hospitals and hotels. Time of use and cooling load profiles are significant factors that should be carefully considered either in chiller plant design or in chiller sequencing operation. This article aims to present an operation planning of HCP which consists of both electric and non-electric chillers. Four operational strategies are proposed and solved to compare their coefficients of performance and economics of running costs. A typical hotel building located on the Nile river in Egypt is selected to perform the current thermal and economic case study. The total cooling load profile of this hotel building is 4000 refrigeration tonnage (TR), which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">simulated to optimize chiller sequence of operation and to select optimal design conditions of both numbers for electric and non-electric chillers used in HCP. The results of this comparative study for running cost are defined using various design configurations with different several chiller sequences available for each configuration. Then, the results of COPs, and operational running cost and initial cost are presented in this article also. The comparison aims to find the optimal design and operational sequencing for HCPs on thermal basis and economic analysis which were attached in this article. Recommendations and suggestions for future work are attached at the end of this article.</span></span></span>
文摘Several media report highlight on that the pharmaceutical companies require ultra-low temperatures -80<span style="white-space:nowrap;">°</span>C to transport and store its COVID-19 vaccines. This research presents the thermodynamic analysis on cascade refrigeration system (CRS) with several refrigerant pairs which are R32/R170, R123/R170, R134a/R170, R404A/R170, R407c/R170, R410/R170, and the hydrocarbon (HC) refrigerant pair Propane/Ethane, namely R290/R170. Besides, the results of R22/R170 pair, which is not recommended to be used due to phase out of R22 as per Montréal Protocol, are included as base case to compare the novel hydrocarbon pairs in CRS and the old trend of refrigerant pairs. Thermodynamic properties of all these pairs were investigated and compared under different intermediate temperature used in CRS heat exchanger, which thermally connected both the Low and High temperature cycles (LTC) and (HTC). By applying the first law of thermodynamics, the coefficients of performance (COPs) and the specific power consumptions (SPC) in kW/TR are presented and compared. In addition, by applying the second law of thermodynamics the exergetic efficiencies were estimated. The results reveal the promising opportunity of using the HC pair (R290/R170). The minimum SPC in kW/TR is recorded for the pair R123/R170. One the other hand, the highest exegetic efficiency values are observed to be 40%, 38%, and 35% for the pairs R123/R170, R290/R170, and R134/R170, respectively. This research concludes that the HC pair (R290/R170) is highly recommended for CRS applications either to transport the COVID-19 or store it in cold storage rooms in hospitals and clinics. All precautionary measures should be carefully applied in design and operation of HC pair (R290/R170) due to its flammability hazard.
文摘In this study, an Artificial Neural Network (ANN) model to predict the pressure drop of turbulent flow of titanium dioxide-water (TiO2-water) is presented. Experimental measurements of TiO2-water under fully developed turbulent flow regime in pipe with different particle volumetric concentrations, nanoparticle diameters, nanofluid temperatures and Reynolds numbers have been used to construct the proposed ANN model. The ANN model was then tested by comparing the predicted results with the measured values at different experimental conditions. The predicted values of pressure drop agreed almost completely with the measured values.
文摘This paper represents a review of the recent researches that investigate the behavior of the gas turbulent flow laden with solid particles. The significant parameters that influence the interactions between the both phases, such as particle size, loading ratio and the gas velocity, have been extensively reviewed. Those parameters are presented in dimensionless numbers in which the applicability of studying its effect in terms of all circumstances of the gas turbulent channel flow at different condition is possible. The represented results show that the turbulence degree is proportional to the particle size. It was found that at the most flow conditions even at low mass ratio, the particle shape, density and size significantly alter the turbulence characteristics. However, the results demonstrate that the particle Reynolds number is a vital sign: the turbulence field becomes weaker if particle Reynolds number is lower than the critical limit and vies verse. The gas velocity has a strong effect on the particles settling along the channel flow and as a result, the pressure drop will be affected.
文摘Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5 × 18 mm2 and the other is triangular with dimension of 5 × 9 mm2. Four channels of each configuration have been etched on copper block of 40 mm width,30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002 - 0.005 m3/s, heating powers of 80 - 200 W and channel base temperatures of 48°C, 51°C, 55°C and 60°C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than trian- gular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ±10%. But for the heat transfer data, the deviation is about +30% to –60% for 1-D model, and –5% to –80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as with accuracy of ±20% for and compared with other literature correlations.
文摘This research aims to present a simplified mathematical model to predict the performance of fire tube boilers, taking into account the necessity of knowing the components of exhaust gases and the extent of their compatibility with environmental laws and requirements. The model shown is for a horizontal, three-pass, wet-back fire tube boiler at steady-state, steady-flow operation. It is concluded from the applicability of the model for different boiler capacity ratings that the results are simplified and important for the boiler manufacturers to predict the performance and make the choice to modify the proposed design to achieve certain needs.
基金supported by the Portuguese Foundation for Science and Technology(FCT)through the project PTDC/CTA-OHR/30561/2017(WinTherface).
文摘Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some parts of the globe,there is an imperative need to develop alternative ways to predict it.Therefore,the main objective of this study is to evaluate the performance of different hybrid data-driven techniques in predicting daily GSR in semi-arid regions,such as the majority of Spanish territory.Here,four ensemble-based hybrid models were developed by hybridizing Additive Regression(AR)with Random Forest(RF),Locally Weighted Linear Regression(LWLR),Random Subspace(RS),and M5P.The base algorithms of the developed models are scarcely applied in previous studies to predict solar radiation.The testing phase outcomes demonstrated that the ARRF models outperform all other hybrid models.The provided models were validated by statisticalmetrics,such as the correlation coefficient(R)and root mean square error(RMSE).The results proved that Scenario#6,utilizing extraterrestrial solar radiation,relative humidity,wind speed,and mean,maximum,and minimum ambient air temperatures as the model inputs,leads to the most accurate predictions among all scenarios(R=0.968–0.988 and RMSE=1.274–1.403 MJ/m^(2)・d).Also,Scenario#3 stood in the next rank of accuracy for predicting the solar radiation in both validating stations.The AD-RF model was the best predictive,followed by AD-RS and AD-LWLR.Hence,this study recommends new effective methods to predict GSR in semiarid regions.
文摘In the present study, dynamic performance of single bed desiccant regeneration system has been investigated experimentally. The desiccant bed operates as an adsorber and then as a regenerator, intermittently. In the experimental work of this investigation, Silica gel is used as a desiccant material. In the regeneration process, hot air from an air heater is blown through the bed using an air blower. The performance of desorption process at different conditions of flowing air is demonstrated. The experimental tests were carried out at different conditions of inlet air and initial bed parameters. Temperature and humidity of air at inlet and exit of the bed were measured. The obtained results showed that hot air with an inlet temperature ranging from 40°C to 75°C could release a notable amount of water from the desiccant bed. The relation between the studied parameters during the desorption processes is correlated. Results also show that the “Rehabilitation period” in desorption process should be eliminated to decrease the desorption time and it could be eliminated if the hot air mass flow rate is greater than 1.92 kg/hr per kg of silica gel.
文摘Al-Baha region, located in Saudi Arabia, is one of the main tourism and leisure areas. The authority at Al-Baha Governorate plans to use clean and renewable energy in its tourism facilities. The importance of this study is to assess the possibility of building a wind farm in Al-Baha and to select the best site for this purpose. This paper presents an analysis of long-term wind data for the annual and monthly variability in Al-Baha region of southwestern Saudi Arabia. Al-Baha region has an area of 9921 square kilometers and is divided into seven regions (groups) based on their similar measurements and wind speed values. The analysis used 40 years of annual and monthly wind speed data between 1981 and 2020. The analysis showed that Group III has the highest mean wind speed values in the northeastern part of the Al-Baha region, ranging from 5.4 m/s to 5.9 m/s at 50 m above the surface. Group VI (5.1 - 5.6 m/s) east of the Al-Baha area recorded the second-highest mean wind speed, while group V southwest of the Al-Baha area recorded lower values. The maximum wind speeds observed in Group III in January, February, March, and July were 6 m/s or higher. A frequency analysis ensures that 79% of the year’s wind speeds exceed 4 m/s at 50 m above the surface of the Group III site. Wind power was considered for 17 wind turbines of different sizes. The Soyut Wind 500 machine was found to produce maximum energy of 1420 MWh/year. The highest performance values for the Soyut Wind 500 machine occurred in winter and summer, while the calculated capacity factor values at a hub height of 50 m were 41% and 32%, respectively. The assessment concluded that generating electricity from wind at G III in the northeast of the Al-Baha region is a good decision.
文摘The efficiency of solar desalination systems is often hindered by the intermittent nature of solar radiation,leading to thermal fluctuations and reduced freshwater yield.This study investigates the integration of flint stones as a low-cost and effective thermal energy storage(TES)medium to enhance the productivity and efficiency of conical solar stills.A series of experimental analyses were conducted using flint stones of varying diameters(1,1.5,2,and 2.5 cm)to determine their impact on thermal regulation,evaporation rates,and freshwater production.The findings revealed that 2 cm flint stones exhibited the highest thermal storage capacity and energy retention,leading to a 40.18%increase in water yield(7.85 L/m^(2)/day)compared to the conventional system(5.6 L/m^(2)/day).Additionally,the system with 2 cm flint stones demonstrated a 119.62%improvement in overall efficiency,135%enhancement in exergy efficiency,and 195%increase in the exergy production factor over the baseline system.The integration of flint stones provided thermal stability by reducing heat loss,maintaining consistent basin water temperatures,and extending the evaporation process beyond peak sunlight hours.This improved the overall stability and continuity of distillation performance throughout the day.Quantitatively,the economic analysis indicated a shortened payback period of 19 days for the optimized system,compared to 27 days for the conventional system,making it a cost-effective and sustainable solution for water-scarce regions.This study is the first to optimize the size of natural flint stones as TES materials in conical solar stills,demonstrating their superior heat retention capacity and significant performance improvement in freshwater production and energy utilization.The results validate the synergy between optimized TES and conical geometry as a promising design strategy for sustainable and affordable solar desalination systems.These findings pave the way for more efficient,economically viable,and environmentally sustainable solar desalination systems to combat global water scarcity.
基金supported by the Science and Technology Projects of State Grid,State Grid Corporation of China(Research on the key technologies of multi-energy complementary distributed energy system).
文摘Proton exchange membrane electrolysis cell(PEMEC)is one of the most promising methods to produce hydrogen at high purity and low power consumption.In this study,a three-dimensional non-isothermal model is used to simulate the cell performance of a typical PEMEC based on computational fluid dynamics(CFD)with the finite element method.Then,the model is used to investigate the distributions of current density,species concentration,and temperature at the membrane/catalyst(MEM/CL)interface.Also,the effects of operating conditions and design parameters on the polarization curve,specific electrical energy demand,and electrical cell efficiency are studied.The results show that the maximum distribution of current density,hydrogen concentration,oxygen concentration,and temperature occur beneath the core ribs and increase towards the channel outlet,while the maximum water concentration distribution happens under the channel and decreases towards the channel exit direction.The increase in gas diffusion layer(GDL)thickness reduces the uneven distribution of the contour at the MEM/CL interface.It is also found that increasing the operating temperature from 323 K to 363 K reduces the cell voltage and specific energy demand.The hydrogen ion diffusion degrades with increasing the cathode pressure,which increases the specific energy demand and reduces the electrical cell efficiency.Furthermore,increasing the thickness of the GDL and membrane rises the specific energy demand and lowers the electrical efficiency,but increasing GDL porosity reduces the specific electrical energy demand and improves the electrical cell efficiency;thus using a thin membrane and GDL is recommended.
文摘The jet pump is an artificial lift employed when the reservoir pressure declines and the well deviation increases.The use of computer well models for optimizing the oil well output has proven to be a suc-cessful strategy,and has helped increasing the efficiency and production of numerous wells.The objective of this study was to use a production optimization technique that achieves some improve-ments,and recommend approaches toward increasing the oil well production.The effects of the motive fluid flow rate and pressure on the oil production rate were investigated to determine the optimal in-jection rate and pressure on the performance of the deep well water-oil axial jet-pump.Additionally,the effects of the well-head pressure,water cut,and roughness of tubing on oil production of this jet pump type were investigated.The results revealed that the impact on the oil lift performance is significant.The oil production increased by 19.43%,and the optimal economic value for the injection rate and pressure for the GA-1A well are 744.44 BFPD and 2722.22 psig,respectively.In summary,increasing the tubing roughness decreased the well's total liquid production.Thus,maintaining the well integrity is a very important factor because not doing so can lower the productivity by up to 20%-25%.
基金supported by the Khalifa Uni-versity under Awards No.CIRA-2018-051 and No.RCII-2019-003.
文摘Increased power density in modern miniaturized electronics caused difficulty in keeping electronic performance effective.This challenge leads to the search for high-performance compact heat exchanger as one of the thermal management solutions.Conventionally manufactured heat exchangers had limitations that thwart the develop-ment of geometrically complex heat exchangers which are capable of exploiting topological aspects to enhance thermal performance.Subsequently,additive manufacturing(AM)is proposed as a powerful fabrication tech-nique for compact heat exchanger based on the mathematically known triply periodic minimal surfaces(TPMS).In this work,we present 3D compact crossflow heat exchanger computational fluid dynamics(CFD)modelling of geometrically complex structures based on TPMS using STARCCM+CFD platform.Moreover,CFD modelling is used to obtain new characteristics maps that relate heat transfer effectiveness(Ɛ)and number of transfer units for the proposed heat exchanger.The convection heat transfer coefficient,pressure drop,and inlet and outlet fluid temperature are all examined.
文摘Biodiesel is derived from waste cooking oil (WCO) by transesterification. Methylester was prepared by mixing diesel and biodiesel oils as 20% by volume. Nano particles asTiO2, Al2O3 and CNTs were blended with biodiesel blend at different concentrations of 25,50, and 100 mg/l to enhance the physicochemical fuel characteristics to obtain clean and effi-cient combustion performance. An experimental setup was incorporated into a diesel engine toinvestigate the influence of these nano-materials on engine performance, exergy analysis, combustion characteristics and emissions using WCO biodiesel-diesel mixture. Enriching methylester mixture with 100 ppm titanium, alumina and CNTs (B20T100, B20A100 andB20C100) increased the thermal efficiency by 4%, 6% and 11.5%, respectively compared toB20. Biodiesel blending with nano additives B20T100, B20A100 and B20C100 decreasedthe emissions of CO (11%, 24% and 30%, respectively), HC (8%, 17% and 25%, respectively)and smoke (10%, 13% and 19%, respectively) compared to B20. However, the noticeable increase of NOx was estimated by 5%, 12% and 27% for B20T100, B20A100 and B20C100,respectively. Finally, the results showed the rise in peak cylinder pressure by 5%, 9% and 11% and increase in heat release rate by 4%, 8% and 13% for B20T100, B20A100 andB20C100, respectively. The fuel exergy of B20T100, B20A100 and B20C100 are lower thanbiodiesel blend B20 by 6.5%, 16% and 23% but the exergetic efficiency are increased by 7%,19% and 30% at full load about B20.
基金carried out in the heat engine laboratory of National Research Centre(NRC),El Dokki,Egypt.Authors greatly appreciate NRC for its endless support to produce the present work.
文摘Extraction of biodiesel from waste cooking oil,jatropha,and corn oils is done by transesterification.Diesel and biodiesel were blended at 20%volume ratio to make methyl ester.At doses of 25,50,and 100 mg/l,carbon nanotubes(CNTs)was mixed with biodiesel blend.The objective of the present research is to examine experimentally a diesel engine performance,combustion characteristics,exergy and emissions analyses with inclusion of nano additive to various methyl ester feedstocks.Methyl ester blend is enriched with CNTs as JB20C100,WB20C100 and CB20C100 where the improvements in thermal efficiency are raised about biodiesel mixture by 9%,13%and 15%,respectively.Addition of 100 ppm of CNTs to biodiesel blends achieves the greatest reductions in CO(14%,22%and 30%),HC(16%,20%and 25%),and smoke emissions(15%,19%and 23%)for JB20C100,WB20C100 and CB20C100,respectively.By comparing with B20,blending 100 ppm CNTs with JB20,CB20,and WB20 obtained the highest increases in cylinder pressure of 3%,5%,and 10%,as well as the highest increases in heat release of 4%,7%,and 11%,respectively.The downside of CNTs addition achieves a rise in NOx emissions by 10%,17%,and 22%for JB20C100,WB20C100,and CB20C100,respectively.Exergetic efficiency increases by 8%,19%,and 24%for B20T100,B20A100,and B20C100,respectively.Sustainability index improvements achieve 1.5%,5%and 6.5%,for B20T100,B20A100,and B20C100,respectively.WB20 with CNTs of 100 ppm is highly recommended for improving engine performance,combustion,and exergy characteristics with considerable emissions reduction.
