Energy and Cost Analysis of Processing Flat Plate Solar Collectors

In this work,a life cycle analysis is accomplished for flat plate solar collectors.The purpose of this investigation is to predict the energy consumption during the manufacturing processes that results in carbon dioxide emissions.Energy consumption and system efficiency enhancement will be studied and predicted.CES EduPack software is used to perform the analysis of the currently commercial system,and the suggested changes are implemented to increase the efficiency and make the comparison.Even though cost analysis is done,the priority of selection is given to the most energy conserving and environmentally friendly alternative.However,if the compared alternatives result in the same energy consumption and CO_(2)emissions,the cost analysis would be a better approach.It can be stated that flat plate solar collectors are sustainable and renewable energy systems that do not produce CO_(2)emissions during their active usage,but the manufacturing processes they undergo during the design contribute to the greenhouse gasses emission.

Experimental investigation of thermal performance characteristics of sintered copper wicked and grooved heat pipes:A comparative study

Heat pipes are most frequently used for thermal management solutions.Selection of right type of heat pipe for a specific scenario is utmost necessary for best outcomes.The purpose of this research is comparison of thermal performance characteristics of sintered copper wicked and grooved heat pipes,which are mostly used types of heat pipes.Distilled water filled heat pipes were tested through experimentation in gravity assisted position.Experimental outcomes have been compiled in terms of capillary pressure,operating temperature,thermal resistance and heat transfer coefficient.Capillary pressure is high in sintered heat pipes compared to grooved heat pipes irrespective of groove dimensions.Grooved heat pipes have lower operating temperature compared to sintered heat pipes at the same heat load.At 8 W,compared to sintered heat pipes,grooved heat pipes have 8.24% lower condenser surface temperature,4.41% lower evaporator surface temperature and 7.79% lower saturation temperature.Thermal resistance of sintered heat pipe is much lower than grooved heat pipe.The maximum relative difference of 63.8% was observed at 8 W.Heat transfer coefficient of sintered heat pipe was observed double compared to grooved heat pipe at 8 W heat load.Thermal resistance and hence heat transfer coefficient of sintered heat pipe change almost in a linear manner with respect to heat load but unexpectedly turning point is observed in thermal resistance and heat transfer coefficient of grooved heat pipe.Grooved heat pipes attain equilibrium much earlier compared to sintered ones.Varying heat loads from 4 to 20 W causes variation in equilibrium establishment time from 7 to 4 min for grooved and from 10 to 7 min for sintered heat pipes.

Modelling and Optimal Design of Hybrid Power System Photovoltaic/Solid Oxide Fuel Cell for a Mediterranean City

This work presents a hybrid power system consisting of photovoltaic and solid oxide fuel cell(PV-SOFC)for electricity production and hydrogen production.The simulation of this hybrid system is adjusted for Bou-Zedjar city in north Algeria.Homer software was used for this simulation to calculate the power output and the total net present cost.The method used depends on the annual average monthly values of clearness index and radiation for which the energy contributions are determined for each component of PV/SOFC hybrid system.The economic study is more important criterion in the proposed hybrid system,and the results show that the cost is very suitable for the use of this hybrid system,which ensures that the area is fed continuously with the sufficient energy for the load which assumed to be 500 kW in the peak season.The optimized results of the present study show that the photovoltaic is capable of generating 8733 kW electricity while the SOFC produces 500 kW electricity.The electrolyzer is capable of producing 238750 kg of hydrogen which is used as fuel in the SOFC to compensate the energy lack in nights and during peak season.

Combustion of Renewable Biogas Fuels

Biogas fuel is a sustainable and renewable fuel produced from anaerobic digestion of organic matter. The biogas fuel is a flammable mixture of methane and carbon dioxide with low to medium calorific values. Biogas is an alternative to conventional fossil fuels and can be used for beating, transportation and power generation. CFD （computational fluid dynamic） analysis of the combustion performance and emissions of biogas fuel in gas turbine engines is presented in this study. The main objective of this study is to understand the impact of the variability in the biogas fuel compositions and lower heating values on the combustion process. Natural gas, biogas from anaerobic digester, landfill biogas, and natural gas/biogas mixture fuels combustion were investigated in this study. The CFD results show lower peak flame temperature and CO mole fractions inside the combustor and lower NOx emissions at the combustor exit for the biogas compared to natural gas fuel. The peak flame temperature decreases by 37% for the biogas landfill （COJCH4 = 0.89） and by 22% for the biogas anaerobic digester （CO2/CH4 = 0.54） compared to natural gas fuel combustion. The peak CO mole fraction inside the combustor decreases from 9.8 × 10-2 for natural gas fuel to 2.22 × 10-4 for biogas anaerobic digester and 1.32 × 10-7 for biogas landfill. The average NOx mole fraction at the combustor exit decreases from 1.13 × 10-5 for natural gas fuel to 0.40 × 10-6 for biogas anaerobic digester and 1.06 × 10-6 for biogas landfill. The presence of non-combustible constituents in the biogas reduces the temperature of the flame and consequently the NOx emissions.

Utilization of Machine Learning Methods in Modeling Specific Heat Capacity of Nanofluids

Nanofluids are extensively applied in various heat transfer mediums for improving their heat transfer characteristics and hence their performance.Specific heat capacity of nanofluids,as one of the thermophysical properties,performs principal role in heat transfer of thermal mediums utilizing nanofluids.In this regard,different studies have been carried out to investigate the influential factors on nanofluids specific heat.Moreover,several regression models based on correlations or artificial intelligence have been developed for forecasting this property of nanofluids.In the current review paper,influential parameters on the specific heat capacity of nanofluids are introduced.Afterwards,the proposed models for their forecasting and modeling are proposed.According to the reviewed works,concentration and properties of solid structures in addition to temperature affect specific heat capacity to large extent and must be considered as inputs for the models.Moreover,by using other effective factors,the accuracy and comprehensive of the models can be modified.Finally,some suggestions are offered for the upcoming works in the relevant topics.

Modeling CO_(2) Emission of Middle Eastern Countries Using Intelligent Methods

CO_(2) emission is considerably dependent on energy consumption and on share of energy sources as well as on the extent of economic activities.Consequently,these factors must be considered for CO_(2) emission prediction for seven middle eastern countries including Iran,Kuwait,United Arab Emirates,Turkey,Saudi Arabia,Iraq and Qatar.In order to propose a predictive model,a Multilayer Perceptron Artificial Neural Network(MLP ANN)is applied.Three transfer functions including logsig,tansig and radial basis functions are utilized in the hidden layer of the network.Moreover,various numbers of neurons are applied in the structure of the models.It is revealed that using MLP ANN makes it possible to accurately predict CO_(2) emission of these countries.In addition,it is concluded that using logsig transfer function leads to the highest accuracy with minimum value of mean squared error(MSE)which is followed by the networks with radial basis and tansig transfer functions.The R-squared of the networks with logsig,radial basis and tansig transfer functions are 0.9998,0.9997 and 0.9996,respectively.Finally,comparison of the proposed model with a similar study,considered five countries in the same region,reveals higher accuracy in term of MSE.

Surface modification techniques of membranes to improve their antifouling characteristics:recent advancements and developments

Extensive research efforts are currently devoted to developing and improving conventional technologies for water treatment. Membrane-based water treatment technologies are among the most preferred options due to their commercial success, simple operation, low energy and space requirements, and high separation efficiency. Despite the advances made in membrane-based technologies, fouling remains a critical challenge. Fouling occurs upon the accumulation of unwanted impurities on the membrane surface and within the membrane pores which results in a significant decline in the membrane permeate flux. To alleviate the operational challenges from fouling, surface modification to develop antifouling membranes appears to be an effective technique. A comprehensive review of the surface modification techniques for the development of antifouling membranes is provided in this paper. Chemical surface modification techniques (grafting and plasma treatment), physical modification techniques (blending, coating, adsorption, and thermal treatment), and combined physical and chemical modification techniques have been discussed. Moreover, the challenges related to surface modification and the future research directions are addressed.

Optimization of synchronized frequency and voltage control for a distributed generation system using the Black Widow Optimization algorithm

A distributed generation network could be a hybrid power system that includes wind-diesel power generation based on induction generators(IGs)and synchronous generators(SGs).The main advantage of these systems is the possibility of using renewable energy in their structures.The most important challenge is to design the voltage-control loop with the frequency-control loop to obtain optimal responses for voltage and frequency deviations.In this work,the voltage-control loop is designed by an automatic voltage regulator.A linear model of the hybrid system has also been developed with coordinated voltage and frequency control.Dynamic frequency response and voltage deviations are compared for different load disturbances and different reactive loads.The gains of the SG and the static volt-ampere reactive compensator(SVC)controllers in the IG terminal are calculated using the Black Widow Optimization(BWO)algorithm to insure low frequency and voltage deviations.The BWO optimization algorithm is one of the newest and most powerful optimization methods to have been introduced so far.The results showed that the BWO algorithm has a good speed in solving the proposed objective function.A 22%improvement in time adjustment was observed in the use of an optimal SVC.Also,an 18%improvement was observed in the transitory values.

Innovative design for a portable hybrid system of hydroponic and microalgae to produce food and biofuels

This study investigates an innovative hybrid system that combines hydroponics and microalgae in a compact portable shipping container.This container is divided into two parts;one contains the microalgae system and the other contains the hydroponic system.This combined system works by dividing the 24 hours into 12 hours of light and 12 hours of dark for each part.Both parts are connected using light-impermeable pipes that pass carbon dioxide from the dark side to the lit side and oxygen from the lit side to the dark side.In this paper,the authors developed a validated mathematical model for hydroponic and microalgae to evaluate the system’s performance.Results found by the model show the optimum parameters for the split photobioreactor and hydroponic system.The first investigated parameter is the sparger diameter for split the photobioreactor and the second is the number of plants that give the better and optimum result.The optimum modelling design for the combined hydroponic and microalgae system was using 100 plants for lettuce and three photobioreactors with a 0.009-m diameter for sparger to a photobioreactor system with an area of 15.6 m^(2).