Journal of Selected Topics in Energy

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Distribution feeder reconfiguration for loss reduction is a very important way to save the electrical energy. This paper proposes a new hybrid evolutionary algorithm to solve the Distribution Feeder Reconfiguration problem (DFR) .The algorithm is based on combination of a New Fuzzy Adaptive Particle Swarm Optimization (NFAPSO) and differential evolution algorithm (DE) called NFAPSO-DE. To exploit the advantages of the exploration ability of DE and the high speed search system and the ability to control and adjust the parameters of PSO algorithm, a hybrid PSO-DE method is proposed. The hybrid method uses the PSO to find the region of optimal solution, and then a combination of PSO and DE to find the optimal solution. In other hand, due to the results of PSO algorithm highly depends on the values of their parameters such as the inertia weight and learning factors, a fuzzy system is employed to adaptively adjust the parameters during the search process. Finally, the proposed algorithm is tested on 33 bus and 69 bus distribution test systems. The results of simulation shows that the proposed method is very powerful and effective to obtain the global optimization.

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Furnaces in refinery and petrochemical processes are major consumers of energy. The most important factors for the controlling the energy consumption of the furnace can be divided into three main groups The first group includes the potential savings without cost or low cost, such as adjusting air – fuel ratio in the burner and pressure control into the furnace, The second group includes the potential savings with medium cost such as insulating body, and the third group includes the potential savings with high investment such as heat recovery from the exhaust flue. In this paper, the thermal energy savings potential on the 4 fixed- furnaces in the Loabiran companies are investigated and calculated that savings potential of adjusting air – fuel ratio in the burner is 165,973,500 Rials in the year, controlling pressure inside the furnace 95,822,300 Rials in the year, body insulation 622,167,700 Rials and recycled flue gases 929,762,400 Rials in the year. Also Loabiran companies uses regenerator that is a periodic heat recovery system to preheat the incoming air. This will result in annual savings for the daily production of 20 tons of frit, are 3,577,000,000 Rials.

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Drag reduction in turbulent flows allows achieving of higher speeds and reducing energy consumption in the motion of submerged objects. An efficient technique for drag reduction uses dilute solutions of microfibers. In this paper, a review of available methods for the simulation of turbulent drag reduction by microfiber additives is presented. To compute the turbulent flow, the direct numerical simulation (DNS) technique is employed. The effect of the fibers on the flow is described by a non-Newtonian stress tensor, involving the distribution of fiber position and orientation. The fiber dynamics is governed by a Fokker-Planck equation. The computation involves a numerical solution of three-dimensional, time-dependent Navier-Stokes equations for the incompressible flow of a non-Newtonian fluid. In this article, various methods for solving the Fokker-Planck equation are reviewed.

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Water shortage and energy crisis are two major challenges for human societies. Solar distillation devices the best solution for converting salt water to fresh water and saline domestic scale using free energy from the sun. This paper presents an overview of a variety of active and passive solar distillation devices for desalination of saline waters in remote rural areas with high solar radiation potential is done.

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The reduction of energy consumption on sensor nodes using cognitive radio network routing algorithm to help Dayjkstra, Can help a lot in increasing the life of nodes and improve the whole problem of the exchange of information without slowing down. Holes containing channel energy threshold is detected and checked by applying a range of secondary users assigned. From the simulation results of cognitive radio-based network routing algorithm can be seen Dayjkstra sensor nodes send data from the source node to the final node of their shortest and best route. Energy consumption by as much as 80 percent less sensor nodes with Dayjkstra algorithm of algorithms such as LEACH, DASC, EEUC that this factor is an increase in the lifetime of nodes in the network.

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Because of increasing demand on new reliable power source for hybrid electric vehicles, lithium-ion (Li-ion) batteries have received much attention in the last decade. Problem free Li-ion batteries are already in use for low power demand applications such as cell phone and laptop battery packs, however; for high power applications such as in automotive propulsion drives, there are serious issues which need to be addressed. Among various issues that high power application lithium-ion (Li-ion) batteries are encountered, thermal issues have received more attention because of their potential to degrade battery performance. In this work, a lumped capacitance heat transfer model is developed in conjunction with a flow network approach to study performance of a commercial-size Lithium-ion battery pack, under various design and operating conditions of a thermal management system. Air, silicon oil and water are chosen as cooling media in the battery pack. Different flow configurations are considered and temperature dispersion, cell-averaged voltage and resistance distributions, and parasitic losses due to the fan/pump power demand are calculated. It is found that application of a coolant with an appropriate viscosity and heat capacity, such as water, in conjunction with a Y-type flow configuration will result in uniform temperature and voltage distributions in the battery pack while keeping the power requirement at low, acceptable levels.

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Considering the significant waste of gas in the oil and gas industry flares, it is highly desired to recover the gas in the industrial processes. Gas recovery reduces the energy consumption as well as the negative environmental impacts. In this study, different flare gas recovery methods are presented from exergy perspectives. Exergy analysis based on the second law overcomes the limitations of the energy-based analysis and offers a much more meaningful evaluation by indicating the association of irreversibilities. Analytical results indicate that simultaneous generation of power and heat by flare gases is the most effective method and can decrease the exergy destruction and fuel gas consumption of the cycle by 77.58 MW and 5793 kg/hr, respectively. When there is no demand for power, recycling the flare gases to process units and steam generating by the turbine exhaust gases can decrease fuel gas consumption of the cycle by 5605 kg/hr. It is also observed that pressurizing and recycling the gas for utility consumption can decrease the exergy destruction and fuel gas consumption of the cycle by 28 MW and 2100 kg/hr, respectively.

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In this work thermal performance of a cylindrical heat pipe at steady state has been investigated empirically. The used heat pipe, made of copper, has been designed and manufactured by considering effective parameters on heat pipe thermal performance. Then heat pipe has been charged by water as the working fluid. By installing sensors and the other equipment, the test set up has been prepared. After preparing the test set up by changing voltage, various input powers have been inserted into evaporator and the heat pipe surface temperature distribution has been obtained for each case. Then by using the obtained temperature distributions, thermal resistance variations and equivalent thermal conductivity coefficient have been computed. and variation of them versus input power have been plotted. The results show that the thermal resistance has its minimum value at maximum operating limit (maximum passing power) and equivalent thermal conductivity has its maximum value at this point.
 

 

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Nowadays, according to increasing energy consumption especially in industry, the need for optimizing energy consumption and determining energy efficiency class of different devices is essential. The main challenge of the present study is developing an energy label instruction for centrifugal pumps. Since the used standard in Iran (ISIRI 7817-2, 1st.edition) only considers the effect of efficiency in energy labeling, a new method is presented to modify this standard. In the proposed method the effect of specific speed on efficiency is considered by choosing one of the constant specific speed curves in η- Q diagram and modifying efficiency for each specific speed. Then, different pumps are tested and labeled by different standards. While the used standard in Iran labels all the pumps in one class, but the new proposed method can label pumps properly as European standards that show the benefit of using the proposed method in centrifugal pumps energy labeling.
 

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In this paper, the optimal operation of pumping stations was determined using a genetic algorithm so that the minimum energy cost. The schedule for the operation of the water pump system can be a significant savings in the cost of energy to be achieved. Determine the optimum pump operation schedule an optimization model - simulation-based genetic algorithm was developed. The model integrates GA optimizer and EPANET hydraulic network solver in MATLAB. The proposed model is applied to find the optimal pump operation schedule of Dogonbadan water conveyance system from Kowsar Dam in an ordinary day of the year. The comparison of optimal schedule with ordinary operation strategy shows 26.8 percent reduction in total energy cost. This indicates the high capability of the proposed model.
 

 

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Solar energy is the most important type of modern and renewable energies. If it displace fossil fuels, can bring an end to concerns about finiteness of fuels, environmental pollution caused by the fossil fuels, price fluctuations and energy crisis. Among the energy sources, due to the high potential of solar energies in wide areas of the Iran, it has a great importance to researchers. The base of Photovoltaic technology is to converting sunlight into electricity and nowadays, most of the countries utilize it in the forms of grid-connected and off-grid. In recent years, few technologies are used for manufacturing of solar cells. The results  of investigating show that the efficiency of the first generation in comparison to the other technologies are high due to the high quality raw materials which are used in the fabrication. It is expected that the differences between the efficiency of these for technologies will be decreased by the time and other technologies will be replaced by the first generation. In this paper, the structure of different technologies has been studied and the possible methods for improvement of the solar cells efficiency have been introduced.
 

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In this study, the effect of using phase change materials on the air-conditioning system energy consumption of a typical room in a multi-floor building has been studied using EnergyPlus software. As the melting point of PCMs has an important impact on their effectiveness, as a part of this research, the effect of Iran climatic conditions on the appropriate melting point of the PCM has been investigated in 4 cities: Tabriz as a cold, Tehran as a moderate, Yazd a dry-hot and Bandar-e-Abbas a humid-hot climate. Based on the results, the proper temperature of PCM melting temperature is between 21 to 27°C and the saving varies from 1.6 to 13.2%. The results of this incestigation are useful in getting better understanding of the effect of PCMs on reducing the HVAC system energy consumption and in determining the PCM appropriate specifications.
 

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The Trombe wall heating system known as one of the most important consumption reduction technology that utilizes solar energy is the energy efficiency. In this paper, the effects of temperature on system performance Trembath glass wall temperature of wall heating Trembath according to the intensity of solar radiation is investigated numerically. The results confirmed the increase in efficiency heating system with regard to solar radiation intensity emitted in the study area. With such intensity 466.281 w / m² close to the glass surface temperature (in air duct) up to 14.422 ° C arrives while lower-intensity radiation (394.91 w / m²) in the final heat to about 12.71 ° C goes. Considering the solar radiation, can be expected to increase the flow of thermal energy in the air duct. The effect of improving the efficiency of the underlying performance heating technology Trembath wall. The results of this study, changes in temperature glass, to the the amount of solar radiation intensity in the relationship. When the radiation intensity maximum the amount of 466.81 w / m² is concerned, more secondary radiation is emitted. As a result, the glass has a temperature range between 11.32 to the 12.73 ° C.

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On a global scale, the pulp and paper industry lead to produce significant amounts of effluents, solid wastes and gaseous wastes, and these wastes originate mainly from the pulping process, deinking and wastewater treatment. Solid biomass in wood waste as well as black liquor of pulping process can be converted to synthetic gas, mainly CO and H₂ by thermal processes, with small amounts of methane, Co₂ and H₂o, and this can be a good opportunity to revive the pulp and paper industry. The main raw materials of biomass in the biorefinery process include hemicellulose, cellulose, lignin and skin, and with mechanical-thermal methods including biomass gasification, black liquor gasification, pyrolysis or liquefaction and carbonization of biomass, synthetic gas can be converted into electricity as well as liquid fuels and chemicals. The results obtained by comparing different hemicellulose pre-extraction technologies of lignocellulosic materials indicate that the steam explosion method is much more environmentally friendly than other alternative methods requiring less investment cost. At present, the use of steam explosion method has increased at the commercial level due to its cost-effectiveness and this method is very efficient for hardwood residues as well as crops leftovers. Also, the organosolve fractionation technology for the separation of hardwoods is well operational and leads to the production of high purity cellulose and the selective dissolution of lignin and hemicellulose. Nanofiltration is a desirable separation method for the recovery of hemicellulose from hydrolysates, and in this regard, the combination of a twin-screw extruder system can be the best way to extract hemicelluloses from hardwood chips. Nanofiltration is much better than ultrafiltration to separate hemicelluloses from hydrolysates by alkaline methods.
 

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In this study, the effect of adding polyisobutylene (PIB) as drag reducing agent (DRA) and nanoSiO₂ particles as heat transfer enhancer to crude oil, separately and also the simultaneous addition of these materials to crude oil as poly-nanofluids (PNFs) in a vertical pipe and under constant heat flux conditions is investigated. The use of drag reducers is one of the most important and simplest methods to overcome some of the energy losses during fluid transpotation. The aim of this study is to investigate the effects of PIB solution and crude oil/silica nanofluid, separately and also the simultaneous effect of adding these two materials, called polyanofluid, on heat transfer and drag reduction in a vertical pipe. In order to make PNFs, polymer-based solutions with concentrations of 10-30 ppm are prepared. Then, nanoSiO₂ with concentrations of 0.1-0.5wt% are added to the base fluid. The experiments were performed in the range of Reynolds 5800-8700 and temperature was 25°C. Experimental conclusions predicted that with increasing Reynolds number, temperature and concentration, Nusslet number and heat transfer rate in supplied nanofluids and PNFs enhanced with nanoparticle concentrations, while PIB concentration cause to reduce thermal propertied and improve the tribological properties of prepared PNFs. This occurrence can be attributed to the formation of the polymeric layer around the nanosilica particles.

 

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 In this study, the effects of non-dimensional amplitude and frequency of pulsating flow are investigated on the heat transfer rate of a circular cylinder in the presence and absence of a splitter plate, for this purpose, at first the heat transfer rate of unpulsating flow is investigated and then compared with the results obtained from the pulsating flow. The pulsating flow over a circular cylinder is studied in the range of pulsating Strouhal number (0.1-2) and amplitude of pulsating flow A=0.75 in the Reynolds number of Re=100. Pulsating flow is one of the factors that can be effective on the heat transfer rate. But in general, the change in the heat transfer rate under pulsating flow depends on non-dimensional amplitude and frequency of pulsating flow. The best case for increasing the heat transfer rate is when the splitter plate is attached to the body. In all range of the pulsating Strouhal number, increase in the Nusselt number in the presence of a splitter plate is reported relative to the absence of splitter plate in pulsating flow.

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 Heat transfer has an effective role in industrial and engineering applications. In this study, the effect of Al₂O₃ nanoparticles on laminar forced convection heat transfer flow in a tube is studied. Governing Equations are discretized using the finite difference method on a staggered grid. Nanofluid flow is simulated using single-phase and mixture models. Simulation results show that the average Nusselt Number increases with an increase in the Reynolds Number. Also, by increasing the volume fraction, the average Nusselt number and consequently the heat transfer rate increases. The results of the mixture model are in better agreement with experimental results than the single-phase model.

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Nowadays, lithium-ion batteries have been commercialized and extensive research is done on improving their properties. The things that are currently the major part of the research are reducing the price of the battery, increasing the energy density of the battery, increasing the lifespan and improving the safety of the battery. In military applications and aviation industries, special attention is paid to battery reliability and safety. The gradual degradation of the materials used in lithium-ion batteries over a long period of time has a negative effect on the electrical performance, lifespan and safety of the battery. This is through increasing the electrical resistance of the battery and even cutting the internal connection of the battery, producing corrosion products and creating passive films on the surface of the material, creating pollutants inside the battery that may react with active materials and leading to loss of uniformity in the material enters the battery and the electrolyte is destroyed. Most of the materials used in lithium-ion batteries were modified after identifying these problems in the battery structure. This article mainly deals with the phenomenon of corrosion in positive and negative current collectors in lithium-ion batteries.