Journal of Renewable Energy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Combustion and Emission Characteristics of Variable Compression Ignition Engine Fueled with Jatropha curcas Ethyl Ester Blends at Different Compression Ratio Wed, 16 Apr 2014 16:20:26 +0000 http://www.hindawi.com/journals/jre/2014/872923/ Engine performance and emission characteristics of unmodified biodiesel fueled diesel engines are highly influenced by their ignition and combustion behavior. In this study, emission and combustion characteristics were studied when the engine operated using the different blends (B10, B20, B30, and B40) and normal diesel fuel (B0) as well as when varying the compression ratio from 16.5 : 1 to 17.5 : 1 to 18.5 : 1. The change of compression ratio from 16.5 : 1 to 18.5 : 1 resulted in 27.1%, 27.29%, 26.38%, 28.48%, and 34.68% increase in cylinder pressure for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions. Higher peak heat release rate increased by 23.19%, 14.03%, 26.32%, 21.87%, and 25.53% for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions, when compression ratio was increased from16.5 : 1 to 18.5 : 1. The delay period decreased by 21.26%, CO emission reduced by 14.28%, and emission increased by 22.84% for B40 blends at 75% of rated load conditions, when compression ratio was increased from 16.5 : 1 to 18.5 : 1. It is concluded that Jatropha oil ester can be used as fuel in diesel engine by blending it with diesel fuel. Rajneesh Kumar and Anoop Kumar Dixit Copyright © 2014 Rajneesh Kumar and Anoop Kumar Dixit. All rights reserved. Design of an Energy System Based on Photovoltaic Thermal Collectors in the South of Algeria Sun, 30 Mar 2014 12:46:46 +0000 http://www.hindawi.com/journals/jre/2014/824529/ The objective of this work is the design of a new energy system where the energy source will be provided by solar photovoltaic thermal (PV/T) hybrid collectors. This system will be applied to a habitation in the region of Ghardaïa in the south of Algeria. The cold water reaches the thermal storage tank and then will be heated by the hybrid collector. The hot water will be used directly as sanitary water. The electric power produced by the hybrid collector will be used to charge the battery and will be delivered to the load (electrical appliances, lamps, etc.). Two types of loads are considered: a DC load and the other alternating current. The fans located adjacent to the radiators supplied with hot water will provide warm air to the house in winter. K. Touafek, A. Khelifa, M. Adouane, and H. Haloui Copyright © 2014 K. Touafek et al. All rights reserved. Design and Modelling of Water Chilling Production System by the Combined Effects of Evaporation and Night Sky Radiation Sun, 02 Mar 2014 00:00:00 +0000 http://www.hindawi.com/journals/jre/2014/624502/ The design and mathematical modelling of thermal radiator panel to be used primarily to measure night sky radiation wet coated surface is presented in this paper. The panel consists of an upper dry surface coated aluminium sheet laminated to an ethylene vinyl acetate foam backing block as an insulation. Water is sprayed onto the surface of the panel so that an evaporative cooling effect is gained in addition to the radiation effect; the surface of a panel then is wetted in order to study and measure the night sky radiation from the panel wet surface. In this case, the measuring water is circulated over the upper face of this panel during night time. Initial TRNSYS simulations for the performance of the system are presented and it is planned to use the panel as calibrated instruments for discriminating between the cooling effects of night sky radiation and evaporation. Ahmed Y. Taha Al-Zubaydi and W. John Dartnall Copyright © 2014 Ahmed Y. Taha Al-Zubaydi and W. John Dartnall. All rights reserved. Determining Balıkesir’s Energy Potential Using a Regression Analysis Computer Program Tue, 25 Feb 2014 08:39:42 +0000 http://www.hindawi.com/journals/jre/2014/975403/ Solar power and wind energy are used concurrently during specific periods, while at other times only the more efficient is used, and hybrid systems make this possible. When establishing a hybrid system, the extent to which these two energy sources support each other needs to be taken into account. This paper is a study of the effects of wind speed, insolation levels, and the meteorological parameters of temperature and humidity on the energy potential in Balıkesir, in the Marmara region of Turkey. The relationship between the parameters was studied using a multiple linear regression method. Using a designed-for-purpose computer program, two different regression equations were derived, with wind speed being the dependent variable in the first and insolation levels in the second. The regression equations yielded accurate results. The computer program allowed for the rapid calculation of different acceptance rates. The results of the statistical analysis proved the reliability of the equations. An estimate of identified meteorological parameters and unknown parameters could be produced with a specified precision by using the regression analysis method. The regression equations also worked for the evaluation of energy potential. Bedri Yüksel and Ergun Ateş Copyright © 2014 Bedri Yüksel and Ergun Ateş. All rights reserved. Magnetic Biofilm Carriers: The Use of Novel Magnetic Foam Glass Particles in Anaerobic Digestion of Sugar Beet Silage Mon, 24 Feb 2014 13:32:20 +0000 http://www.hindawi.com/journals/jre/2014/208718/ The use of recently developed magnetic foam glass particles for immobilization of microbial biomass was tested. The effect of the particles was illustrated at the production of biogas from sugar beet silage as the sole substrate. Lab-scale fermentation experiments were conducted using a mesophilic completely stirred tank reactor and a magnetic separator. Microscopic analysis revealed biofilm coverage of 50–60% on the surface of the particles within 110 days. It was possible to recover 76.3% of the particles from fermentation effluent by means of a separation procedure based on magnetic forces. Comparing a particle charged reactor with a control reactor showed a small performance gain. The methane rate was increased from to  L L−1 d−1 and the methane yield was increased from to  L g−1 (volatile solids) at an organic loading rate of  g L−1 d−1 (volatile solids). Maximum methane rates of 1.42 L L−1 d−1 at an organic loading rate of 4.60 g (volatile solids) L−1 d−1 (reactor including magnetic particles) and 1.34 L L−1 d−1 at 3.73 g L−1 d−1 (control reactor) were achieved. Based on the results, it can be concluded that the use of magnetic particles could be an attractive option for the optimization of biogas production. Patrice Ramm, Carsten Jost, Elisabeth Neitmann, Ulrich Sohling, Oliver Menhorn, Karl Weinberger, Jan Mumme, and Bernd Linke Copyright © 2014 Patrice Ramm et al. All rights reserved. A Review of the Wood Pellet Value Chain, Modern Value/Supply Chain Management Approaches, and Value/Supply Chain Models Mon, 27 Jan 2014 07:13:23 +0000 http://www.hindawi.com/journals/jre/2014/654158/ We reviewed 153 peer-reviewed sources to provide identification of modern supply chain management techniques and exploration of supply chain modeling, to offer decision support to managers. Ultimately, the review is intended to assist member-companies of supply chains, mainly producers, improve their current management approaches, by directing them to studies that may be suitable for direct application to their supply chains and value chains for improved efficiency and profitability. We found that information on supply chain management and modeling techniques in general is available. However, few Canadian-based published studies exist regarding a demand-driven modeling approach to value/supply chain management for wood pellet production. Only three papers were found specifically on wood pellet value chain analysis. We propose that more studies should be carried out on the value chain of wood pellet manufacturing, as well as demand-driven management and modeling approaches with improved demand forecasting methods. Natalie M. Hughes, Chander Shahi, and Reino Pulkki Copyright © 2014 Natalie M. Hughes et al. All rights reserved. FEMAN: Fuzzy-Based Energy Management System for Green Houses Using Hybrid Grid Solar Power Sun, 01 Sep 2013 13:28:22 +0000 http://www.hindawi.com/journals/jre/2013/785636/ The United Nations has designated the year 2012 as the international year of sustainable energy. Today, we are seeing a rise in global awareness of energy consumption and environmental problems. Many nations have launched different programs to reduce the energy consumption in residential and commercial buildings to seek lower-carbon energy solutions. We are talking about the future green and smart houses. The subject of smart/green houses is not one of “why,” but rather “how,” specifically: “how making the future house more energy efficient.” The use of the renewable energy, the technology and the services could help us to answer this question. Intelligent home energy management is an approach to build centralized systems that deliver application functionality as services to end-consumer applications. The objective of this work is to develop a smart and robust controller for house energy consumption with maximizing the use of solar energy and reducing the impact on the power grid while satisfying the energy demand of house appliances. We proposed a fuzzy-based energy management controller in order to reduce the consumed energy of the building while respecting a fixed comfort. Abdellah Chehri and Hussein T. Mouftah Copyright © 2013 Abdellah Chehri and Hussein T. Mouftah. All rights reserved. Modeling and Characteristic Analysis of a Solar Parabolic Trough System: Thermal Oil as the Heat Transfer Fluid Sun, 18 Aug 2013 09:42:28 +0000 http://www.hindawi.com/journals/jre/2013/389514/ The thermal oil is applied as the heat transfer fluid in a solar parabolic trough collector system. Firstly, the system dynamic model was established and validated by the real operating data in typical summer and spring days in references. Secondly, the alteration characteristics of different solar radiation, inlet water temperature and flow rate, and collectors’ area and length are analyzed and compared with the normal working condition. The model can be used for studying, system designing, and better understanding of the performance of parabolic trough systems. Zhai Rongrong, Yang Yongping, Yan Qin, and Zhu Yong Copyright © 2013 Zhai Rongrong et al. All rights reserved. The Effectiveness of Feature Selection Method in Solar Power Prediction Tue, 06 Aug 2013 08:27:55 +0000 http://www.hindawi.com/journals/jre/2013/952613/ This paper empirically shows that the effect of applying selected feature subsets on machine learning techniques significantly improves the accuracy for solar power prediction. Experiments are performed using five well-known wrapper feature selection methods to obtain the solar power prediction accuracy of machine learning techniques with selected feature subsets. For all the experiments, the machine learning techniques, namely, least median square (LMS), multilayer perceptron (MLP), and support vector machine (SVM), are used. Afterwards, these results are compared with the solar power prediction accuracy of those same machine leaning techniques (i.e., LMS, MLP, and SVM) but without applying feature selection methods (WAFS). Experiments are carried out using reliable and real life historical meteorological data. The comparison between the results clearly shows that LMS, MLP, and SVM provide better prediction accuracy (i.e., reduced MAE and MASE) with selected feature subsets than without selected feature subsets. Experimental results of this paper facilitate to make a concrete verdict that providing more attention and effort towards the feature subset selection aspect (e.g., selected feature subsets on prediction accuracy which is investigated in this paper) can significantly contribute to improve the accuracy of solar power prediction. Md Rahat Hossain, Amanullah Maung Than Oo, and A. B. M. Shawkat Ali Copyright © 2013 Md Rahat Hossain et al. All rights reserved. Propagation of Shock on NREL Phase VI Wind Turbine Airfoil under Compressible Flow Sun, 28 Jul 2013 08:30:57 +0000 http://www.hindawi.com/journals/jre/2013/653103/ The work is focused on numeric analysis of compressible flow around National Renewable Energy Laboratory (NREL) phase VI wind turbine blade airfoil S809. Although wind turbine airfoils are low Reynolds number airfoils, a reasonable investigation of compressible flow under extreme condition might be helpful. A subsonic flow (mach no. ) has been considered for this analysis and the impacts of this flow under seven different angles of attack have been determined. The results show that shock takes place just after the mid span at the top surface and just before the mid span at the bottom surface at zero angle of attack. Slowly the shock waves translate their positions as angle of attack increases. A relative translation of the shock waves in upper and lower face of the airfoil are presented. Variation of Turbulent viscosity ratio and surface Y+ have also been determined. A k-ω SST turbulent model is considered and the commercial CFD code ANSYS FLUENT is used to find the pressure coefficient (Cp) as well as the lift (CL) and drag coefficients (CD). A graphical comparison of shock propagation has been shown with different angle of attack. Flow separation and stream function are also determined. Mohammad A. Hossain, Ziaul Huque, and Raghava R. Kammalapati Copyright © 2013 Mohammad A. Hossain et al. All rights reserved. Evaluation of Harmonic Content from a Tap Transformer Based Grid Connection System for Wind Power Sun, 21 Jul 2013 10:48:38 +0000 http://www.hindawi.com/journals/jre/2013/190573/ Simulations done in MATLAB/Simulink together with experiments conducted at the Ångströms laboratory are used to evaluate and discuss the total harmonic distortion (THD) and total demand distortion (TDD) of a tap transformer based grid connection system. The grid connection topology can be used with different turbine and generator topologies and is here applied on a vertical axis wind turbine (VAWT) with a permanent magnet synchronous generator (PMSG) and its operational scheme. The full variable-speed wind conversion system consists of a diode rectifier, DC link, IGBT inverter, LCL-filter, and tap transformer. The full variable-speed operation is enabled by the use of the different step-up ratios of the tap transformer. In the laboratory study, a full experimental setup of the system was used, a clone of the on-site PMSG driven by a motor was used, and the grid was replaced with a resistive load. With a resistive load, grid harmonics and possible unbalances are removed. The results show a TDD and THD below 5% for the full operating range and harmonic values within the limits set up by IEEE-519. Furthermore, a change in tap, going to a lower step-up ratio, results in a reduction in both THD and TDD for the same output power. S. Apelfröjd and S. Eriksson Copyright © 2013 S. Apelfröjd and S. Eriksson. All rights reserved. Evaluation of Potential Geographic Distribution for Large-Scale Photovoltaic System in Suburbs of China Sun, 21 Jul 2013 09:24:00 +0000 http://www.hindawi.com/journals/jre/2013/106063/ Since China is the largest CO2 emitting country in the world, photovoltaic (PV) systems are expected to be widely installed to reduce CO2 emission. In general, available area for PV installation depends on urban area due to differences in land use and slope. Amount of electricity generated by a PV system also depends on urban area because of differences in solar irradiation and ambient temperature. The aim of this study is to evaluate the installation of large-scale PV systems in suburbs of China, taking these differences into consideration. We have used a geographic information system (GIS) to evaluate amounts of installation capacity of large-scale PV systems, electricity generated, and CO2 emission reduction by the installation capacity of large-scale PV systems in suburbs of Liaoning, Shanghai, Anhui, and Guangdong. In Liaoning, the amount of CO2 emission reduction by the installation capacity of large-scale PV systems was estimated to be the largest, 3,058 kt-CO2/yr, due to its larger amount of the installation capacity, 2439.4 MW, than the amount of the installation capacity in other regions. Masashi Kawase, Keiichi Okajima, and Yohji Uchiyama Copyright © 2013 Masashi Kawase et al. All rights reserved. Optimization of the Energy Output of Osmotic Power Plants Tue, 16 Jul 2013 12:57:58 +0000 http://www.hindawi.com/journals/jre/2013/496768/ On the way to a completely renewable energy supply, additional alternatives to hydroelectric, wind, and solar power have to be investigated. Osmotic power is such an alternative with a theoretical global annual potential of up to 14400 TWh (70% of the global electricity consumption of 2008) per year. It utilizes the phenomenon that upon the mixing of fresh water and oceanic salt water (e.g., at a river mouth), around 2.88 MJ of energy per 1 m3 of fresh water is released. Here, we describe a new approach to derive operational parameter settings for osmotic power plants using a pressure exchanger for optimal performance, either with respect to maximum generated power or maximum extracted energy. Up to now, only power optimization is discussed in the literature, but when considering the fresh water supply as a limiting factor, the energy optimization appears as the challenging task. Florian Dinger, Tobias Tröndle, and Ulrich Platt Copyright © 2013 Florian Dinger et al. All rights reserved. Computational Study on the Aerodynamic Performance of Wind Turbine Airfoil Fitted with Coandă Jet Mon, 27 May 2013 12:40:10 +0000 http://www.hindawi.com/journals/jre/2013/839319/ Various methods of flow control for enhanced aerodynamic performance have been developed and applied to enhance and control the behavior of aerodynamic components. The use of Coandă effect for the enhancement of circulation and lift has gained renewed interest, in particular with the progress of CFD. The present work addresses the influence, effectiveness, and configuration of Coandă-jet fitted aerodynamic surface for improving lift and , specifically for S809 airfoil, with a view on its incorporation in the wind turbine. A simple two-dimensional CFD modeling using - turbulence model is utilized to reveal the key elements that could exhibit the desired performance for a series of S809 airfoil configurations. Parametric study performed indicates that the use of Coandă-jet S809 airfoil can only be effective in certain range of trailing edge rounding-off radius, Coandă-jet thickness, and momentum jet size. The location of the Coandă-jet was found to be effective when it is placed close to the trailing edge. The results are compared with experimental data for benchmarking. Three-dimensional configurations are synthesized using certain acceptable assumptions. A trade-off study on the S809 Coandă configured airfoil is needed to judge the optimum configuration of Coandă-jet fitted Wind-Turbine design. H. Djojodihardjo, M. F. Abdul Hamid, A. A. Jaafar, S. Basri, F. I. Romli, F. Mustapha, A. S. Mohd Rafie, and D. L. A. Abdul Majid Copyright © 2013 H. Djojodihardjo et al. All rights reserved. Pretreated Landfill Gas Conversion Process via a Catalytic Membrane Reactor for Renewable Combined Fuel Cell-Power Generation Wed, 08 May 2013 16:02:37 +0000 http://www.hindawi.com/journals/jre/2013/209364/ A new landfill gas-based reforming catalytic processing system for the conversion of gaseous hydrocarbons, such as incoming methane to hydrogen and carbon oxide mixtures, is described and analyzed. The exit synthesis gas (syn-gas) is fed to power effectively high-temperature fuel cells such as SOFC types for combined efficient electricity generation. The current research work is also referred on the description and design aspects of permreactors (permeable reformers) carrying the same type of landfill gas-reforming reactions. Membrane reactors is a new technology that can be applied efficiently in such systems. Membrane reactors seem to perform better than the nonmembrane traditional reactors. The aim of this research includes turnkey system and process development for the landfill-based power generation and fuel cell industries. Also, a discussion of the efficient utilization of landfill and waste type resources for combined green-type/renewable power generation with increased processing capacity and efficiency via fuel cell systems is taking place. Moreover, pollution reduction is an additional design consideration in the current catalytic processors fuel cell cycles. Zoe Ziaka and Savvas Vasileiadis Copyright © 2013 Zoe Ziaka and Savvas Vasileiadis. All rights reserved. Case Study of Integrating an Offshore Wind Farm with Offshore Oil and Gas Platforms and with an Onshore Electrical Grid Mon, 29 Apr 2013 15:01:47 +0000 http://www.hindawi.com/journals/jre/2013/607165/ This research project explored the technical feasibility of utilizing an offshore wind farm as a supplementary power source to several electrical grids of offshore oil and gas platforms and providing surplus power to an onshore grid. Three case studies comprising wind farms rated at 20 MW, 100 MW, and 1000 MW have been studied with the focus on (i) the operation benefits of CO2/NOx emission reduction, (ii) the electrical grid stability, and (iii) the technical implementation feasibility. The proposed 20 MW, 100 MW, and 1000 MW wind farm cases are theoretically feasible in terms of the selected technical criteria, although further detailed design operational studies, and economical analysis are required. Wei He, Kjetil Uhlen, Mahesh Hadiya, Zhe Chen, Gang Shi, and Emilio del Rio Copyright © 2013 Wei He et al. All rights reserved. Performance Evaluation of a Double-Glazed Box-Type Solar Oven with Reflector Sun, 28 Apr 2013 18:06:22 +0000 http://www.hindawi.com/journals/jre/2013/184352/ This research paper describes the performance evaluation of a double-glazed box-type solar oven with reflector fabricated using locally available materials, compressed sawdust with binder; size of the box is 700 mm ×  700 mm × 400 mm and 10 mm thickness. The experimental solar cooker consists of an aluminium absorber plate (1 mm) painted matt black and a double-glazed lid. The bottom and sides are lagged with fibreglass wool insulator, thickness = 50 mm,  W/m°C. The reflector consists of a wooden-framed commercially available specular plane mirror which is sized to form a cover for the box when not being in use. Its thermal performance was tested according to the ASAE International Test procedure and Bureau of Indian Standards (BIS) for testing the thermal performance of box-type solar cooker. Thermal performance experiments were conducted in order to determine the first figure of merit (F1), the second figure of merit (F2) and standard cooking power (Ps). The obtained test results were employed to calculate the two figures of merit (F1, and F2) and the standard cooking power (P50) to be 0.11 Km2w−1, 0.31, and 23.95 W, respectively. Finally, the results illustrated that the cooker has a good reliability for cooking food and boiling water. Joshua Folaranmi Copyright © 2013 Joshua Folaranmi. All rights reserved. Ventilated Double Window for the Preheating of the Ventilation Air Comparison of Its Performance in a Northern and a Southern European Climate Tue, 16 Apr 2013 14:38:23 +0000 http://www.hindawi.com/journals/jre/2013/290865/ Keeping the indoor air quality within the reference levels requires that the polluted indoor air be replaced by fresh air coming from the outside. This paper presents a sensitivity analysis and a series of simulations where the performance of this passive system is studied. The influence of each relevant factor, like the wind, the solar radiation, and the outdoor air temperature, is assessed. Two different local sets of climatic data were chosen, a mild and a cold winter. Jorge S. Carlos and Helena Corvacho Copyright © 2013 Jorge S. Carlos and Helena Corvacho. All rights reserved. Investigation of Energy Storage Systems, Its Advantage and Requirement in Various Locations in Australia Thu, 11 Apr 2013 18:56:00 +0000 http://www.hindawi.com/journals/jre/2013/835309/ Storage minimizes the intermittent nature of renewable sources. Solar and wind are the two fostered source of renewable energy. However, the availability of useful solar radiation and wind speed varies with geographical locations, and also the duration of this energy sources varies with seasonal variation. With the available vast open land and geographical position, Australia has great potential for both solar and wind energies. However, both these sources require energy buffering to support load demand to ensure required power quality. Electricity demand is increasing gradually, and also Australia has target to achieve 20% electricity from renewable sources by 2020. For effective utilization of solar and wind energy potential location of these sources needs to be identified, and effective size of storage needs to be estimated for best utilization according to the load demand. Therefore this paper investigated wind speed and solar radiation data of 210 locations in Australia, identified the potential locations, and estimated required storage in various potential locations to support residential load demand. Advantages of storage were analyzed in terms of loading on distribution transformer and storage support during energy fluctuation from renewable energy. Further analysis showed that storage greatly reduces greenhouse gas emission and reduces overall cost of energy by maximizing the use of solar and wind energies. Mohammad Taufiqul Arif, Amanullah M. T. Oo, and A. B. M. Shawkat Ali Copyright © 2013 Mohammad Taufiqul Arif et al. All rights reserved. An Algorithm to Determine the Optimum Tilt Angle of a Solar Panel from Global Horizontal Solar Radiation Tue, 09 Apr 2013 10:37:04 +0000 http://www.hindawi.com/journals/jre/2013/307547/ This paper proposes an algorithm to calculate the optimum tilt angle of solar panels by means of global horizontal solar radiation data, provided from Earth-based meteorological stations. This mathematical modeling is based on the maximization of the theoretical expression of the global solar irradiation impinging on an inclined surface, with respect to the slope and orientation of the panel and to the solar hour angle. A set of transcendent equations resulted, whose solutions give the optimum tilt and orientation of a solar panel. A simulation was carried out using global horizontal solar radiation data from the European Solar Radiation Atlas and some empirical models of diffuse solar radiation. The optimum tilt angle resulted was related to latitude by a linear regression with significant correlation coefficients. The standard error of the mean values resulted increased significantly with latitude, suggesting that unreliable values can be provided at high latitudes. Emanuele Calabrò Copyright © 2013 Emanuele Calabrò. All rights reserved. Economic Efficiency Assessment of Autonomous Wind/Diesel/Hydrogen Systems in Russia Mon, 08 Apr 2013 08:10:36 +0000 http://www.hindawi.com/journals/jre/2013/101972/ The economic efficiency of harnessing wind energy in the autonomous power systems of Russia is analyzed. Wind turbines are shown to be competitive for many considered variants (groups of consumers, placement areas, and climatic and meteorological conditions). The authors study the possibility of storing energy in the form of hydrogen in the autonomous wind/diesel/hydrogen power systems that include wind turbines, diesel generator, electrolyzer, hydrogen tank, and fuel cells. The paper presents the zones of economic efficiency of the system (set of parameters that provide its competitiveness) depending on load, fuel price, and long-term average annual wind speed. At low wind speed and low price of fuel, it is reasonable to use only diesel generator to supply power to consumers. When the fuel price and wind speed increase, first it becomes more economical to use a wind-diesel system and then wind turbines with a hydrogen system. In the latter case, according to the optimization results, diesel generator is excluded from the system. O. V. Marchenko and S. V. Solomin Copyright © 2013 O. V. Marchenko and S. V. Solomin. All rights reserved. The Effects of Trace Elements on the Lipid Productivity and Fatty Acid Composition of Nannochloropis oculata Wed, 03 Apr 2013 16:12:00 +0000 http://www.hindawi.com/journals/jre/2013/671545/ The effects of trace elements on the lipid productivity and fatty acid composition of Nannochloropis oculata (N. oculata) were studied. The results showed that trace elements had a strong influence on not only the lipid productivity but also the fatty acid composition. The addition of Fe3+, Zn2+, Mn2+, Mo6+, and EDTA and the deletion of Cu2+ and Co2+ can increase the lipid productivity. The optimum concentrations of the trace elements in the culture medium are 6 times of Fe3+ and EDTA, the same concentration of Zn2+, Mn2+, and Mo6+ as the control group, but the optimum medium has no Cu2+ or Co2+. Fe3+, Zn2+, Mn2+, Mo6+, and EDTA are indispensable during the EPA formation of N. oculata. The addition of Fe3+, Zn2+, Mn2+, Mo6+, and EDTA can strongly increase the content of EPA in the lipid of N. oculata, but the concentration of the trace elements had little influence on the level of EPA. Xiao Dou, Xiang-Hong Lu, Mei-Zhen Lu, Li-Sheng Yu, Rong Xue, and Jian-Bing Ji Copyright © 2013 Xiao Dou et al. All rights reserved. Solar Energy Potential Assessment in the Algerian South Area: Case of Ghardaïa Region Mon, 25 Mar 2013 16:11:21 +0000 http://www.hindawi.com/journals/jre/2013/496348/ Due to its geographical position in the solar belt, Algeria is blessed with an abundance of solar energy and has the opportunity to utilize this bounty of natural energy effectively, promoting a clean environment and developing renewable energy technologies in the region. This paper assesses and analyses the solar energy potential in Ghardaïa area (south Algeria) to help users for solar energy applications. A database of solar radiation components has been employed for this purpose. The data presented in the paper are compared with other data supplied by renowned regional and international establishments, such as the solar atlas for the Mediterranean and the NASA. The frequency and the hourly distribution of solar radiation components indicate that the region is considered as an economical area and favorable for solar applications, such as the photovoltaic and the concentrating solar power (CSP) technologies. In addition to solar radiation, data of two functions, namely, clearness index and sunshine fraction have been examined; their results specify that the site has a clear sky conditions in most time of the year. In general, the obtained results illustrate that the site under consideration can use solar energy as a promising solution to conventional energy. Kacem Gairaa and Yahia Bakelli Copyright © 2013 Kacem Gairaa and Yahia Bakelli. All rights reserved. Intelligent Photovoltaic Maximum Power Point Tracking Controller for Energy Enhancement in Renewable Energy System Wed, 20 Mar 2013 17:18:25 +0000 http://www.hindawi.com/journals/jre/2013/901962/ Photovoltaic (PV) system is one of the promising renewable energy technologies. Although the energy conversion efficiency of the system is still low, but it has the advantage that the operating cost is free, very low maintenance and pollution-free. Maximum power point tracking (MPPT) is a significant part of PV systems. This paper presents a novel intelligent MPPT controller for PV systems. For the MPPT algorithm, an optimized fuzzy logic controller (FLC) using the Hopfield neural network is proposed. It utilizes an automatically tuned FLC membership function instead of the trial-and-error approach. The MPPT algorithm is implemented in a new variant of coupled inductor soft switching boost converter with high voltage gain to increase the converter output from the PV panel. The applied switching technique, which includes passive and active regenerative snubber circuits, reduces the insulated gate bipolar transistor switching losses. The proposed MPPT algorithm is implemented using the dSPACE DS1104 platform software on a DS1104 board controller. The prototype MPPT controller is tested using an agilent solar array simulator together with a 3 kW real PV panel. Experimental test results show that the proposed boost converter produces higher output voltages and gives better efficiency (90%) than the conventional boost converter with an RCD snubber, which gives 81% efficiency. The prototype MPPT controller is also found to be capable of tracking power from the 3 kW PV array about 2.4 times more than that without using the MPPT controller. Subiyanto, Azah Mohamed, and M. A. Hannan Copyright © 2013 Subiyanto et al. All rights reserved. Effect of Briquetting Process Variables on Hygroscopic Property of Water Hyacinth Briquettes Sun, 17 Mar 2013 17:22:24 +0000 http://www.hindawi.com/journals/jre/2013/429230/ The knowledge of water resistance capacity of briquettes is important in order to determine how sensitive the produced briquettes are to moisture change during storage. The relative changes in length and diameter of briquettes during immersion in water for 6 hours were investigated. This was conducted to determine hygroscopic property of produced briquettes under process variables levels of binder (10, 20, 30, 40, and 50%) by weight of residue, compaction pressure (3.0, 5.0, 7.0, and 9.0 MPa) and particle size (0.5, 1.6, and 4 mm of dried and ground water hyacinth). Data was statistically analysed using Analysis of Variance, the Duncan Multiple Range Test, and descriptive statistics. The relative change in length of briquettes with process variables ranged significantly from % to % (binder), % to % (compaction pressure), and % to % (particle size) (). Furthermore, the relative change in diameter of briquettes with binder, compaction pressure, and particle size varied significantly from % to %, % to %, and % to %, respectively (). This study suggests optimum process variables required to produce briquettes of high water resistance capacity for humid environments like the Niger Delta, Nigeria, as 50% (binder proportion), 9 MPa (compaction pressure), and 0.5 mm (particle size). R. M. Davies and O. A. Davies Copyright © 2013 R. M. Davies and O. A. Davies. All rights reserved. A Technical Note on Fabrication and Thermal Performance Studies of a Solar Pond Model Thu, 14 Mar 2013 10:17:37 +0000 http://www.hindawi.com/journals/jre/2013/475282/ A solar pond has been fabricated to analyze the thermal behavior of it, in the climatic conditions of Moradabad, Uttar Pradesh. Sodium chloride (NaCl) has been used to form a salt gradient for better performance, and a dark-colored (blackened) rigid surface bottom with 1 mm irregularities has been considered for trapping the heat in a good amount. A solar pond with a surface area of 2.56 m2 and a depth of 1 m has been filled with salty water of various densities to form three salty water zones (upper convective, nonconvective, and heat storage). A few investigations have been carried out to evaluate the thermal efficiencies of three different zones of the solar pond. An attempt is also made to improve the thermal performance of the salt gradient solar pond. Abhishek Saxena and Varun Goel Copyright © 2013 Abhishek Saxena and Varun Goel. All rights reserved. Investigations on Performance and Emission Characteristics of Diesel Engine with Biodiesel (Jatropha Oil) and Its Blends Thu, 14 Mar 2013 09:20:57 +0000 http://www.hindawi.com/journals/jre/2013/163829/ This paper presents the performance of biodiesel blends in a single-cylinder water-cooled diesel engine. All experiments were carried out at constant speed 1500 rpm and the biodiesel blends were varied from B10 to B100. The engine was equipped with variable compressions ratio (VCR) mechanism. For 100% Jatropha biodiesel, the maximum fuel consumption was 15% higher than that of diesel fuel. The brake thermal efficiency for biodiesel and its blends was found to be slightly higher than that of diesel at various load conditions. The increase in specific fuel consumption ranged from 2.75% to 15% for B10 to B100 fuels. The exhaust gas temperature increased with increased biodiesel blend. The highest exhaust gas temperature observed was 430°C with biodiesel for load conditions 1.5 kW, 2.5 kW, and 3.5 kW, where as for diesel the maximum exhaust gas temperature was 440°C. The CO2 emission from the biodiesel fuelled engine was higher by 25% than diesel fuel at full load. The CO emissions were lower with Jatropha by 15%, 13%, and 13% at 1.5 kW, 2.5 kW, and 3.5 kW load conditions, respectively. The emissions were higher by 16%, 19%, and 20% at 1.5 kW, 2.5 kW, and 3.5 kW than that of the diesel, respectively. Amar Pandhare and Atul Padalkar Copyright © 2013 Amar Pandhare and Atul Padalkar. All rights reserved. Material Demands for Storage Technologies in a Hydrogen Economy Wed, 13 Mar 2013 13:56:13 +0000 http://www.hindawi.com/journals/jre/2013/878329/ A hydrogen economy is needed, in order to resolve current environmental and energy-related problems. For the introduction of hydrogen as an important energy vector, sophisticated materials are required. This paper provides a brief overview of the subject, with a focus on hydrogen storage technologies for mobile applications. The unique properties of hydrogen are addressed, from which its advantages and challenges can be derived. Different hydrogen storage technologies are described and evaluated, including compression, liquefaction, and metal hydrides, as well as porous materials. This latter class of materials is outlined in more detail, explaining the physisorption interaction which leads to the adsorption of hydrogen molecules and discussing the material characteristics which are required for hydrogen storage application. Finally, a short survey of different porous materials is given which are currently investigated for hydrogen storage, including zeolites, metal organic frameworks (MOFs), covalent organic frameworks (COFs), porous polymers, aerogels, boron nitride materials, and activated carbon materials. M. Kunowsky, J. P. Marco-Lózar, and A. Linares-Solano Copyright © 2013 M. Kunowsky et al. All rights reserved. Investment and Economy Analysis of Water-Source Heat Pump System in Chongqing, China Thu, 07 Mar 2013 14:07:15 +0000 http://www.hindawi.com/journals/jre/2013/574196/ In China, the application of renewable energy witnesses rapid development. In the near future, a lot of demonstration projects will be built and thus it is urgent to know the economics of renewable energy building application technologies. Based on the renewable energy demonstration projects in Chongqing city, the author discussed the economy issue of water-source heat pump system (WSHPs) in order to provide suggestions for the application projects. According to the design information of demonstration projects, the average incremental investment, allowance, and payback period are calculated in this paper. Comparing WSHPs with traditional heating, ventilation, and air conditioning (HVAC) system, the saved energy of WSHPs is estimated in the current paper. The author calculated the amount of saved energy in unit applied area and unit intake water. Besides, the economy and efficiency of WSHPs project is analyzed at the end of this paper. Yong Ding, Xin Huang, Xiaobo Wu, and Baizhan Li Copyright © 2013 Yong Ding et al. All rights reserved. Moisture Sorption Characteristics of Corn Stover and Big Bluestem Wed, 06 Feb 2013 09:16:28 +0000 http://www.hindawi.com/journals/jre/2013/939504/ Moisture content is an important feedstock quality in converting it into energy through biochemical or thermochemical platforms. Knowledge of moisture sorption relationship is useful in drying and storage to preserve the quality of feedstocks. Moisture sorption isotherms for potential feedstocks such as corn stover and big bluestem are missing. EMC values of corn stover and big bluestem were determined using static gravimetric technique with saturated salt solutions (ERH 0.12–0.89) at different temperatures (20, 30, and 40°C). Depending upon the ERH values, EMC values were ranged from 8.0 to 19.6 and 8.8 to 19.2% db for corn stover and big bluestem, respectively, and they followed typical type II isotherm found in food materials. Nonlinear regression was used to fit five commonly used three-parameter isotherm models (i.e., modified Oswin model, modified Halsey model, modified Chung-Pfost model, modified Henderson model, and the modified Guggenheim-Anderson-de Boer (GAB) model) to the experimental data. Modified Halsey emerged as the best model with high -statistic and values with low and and fairly random scattered residual plot for corn stover and big bluestem. These models can be used to predict the equilibrium moisture content of these feedstocks starting from harvesting, drying, preprocessing, transportation, storage, and conversion. C. Karunanithy, K. Muthukumarappan, and A. Donepudi Copyright © 2013 C. Karunanithy et al. All rights reserved.