Journal of Energy The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Power Consumption: Base Stations of Telecommunication in Sahel Zone of Cameroon: Typology Based on the Power Consumption—Model and Energy Savings Mon, 18 Jul 2016 11:54:49 +0000 In this paper, the work consists of categorizing telecommunication base stations (BTS) for the Sahel area of Cameroon according to their power consumption per month. It consists also of proposing a model of a power consumption and finally proceeding to energy audits in each type of base station in order to outline the possibilities of realizing energy savings. Three types of telecommunication base stations (BTS) are found in the Sahel area of Cameroon. The energy model takes into account power consumption of all equipment located in base stations (BTS). The energy audits showed that mismanagement of lighting systems, and of air-conditioning systems, and the type of buildings increased the power consumption of the base station. By applying energy savings techniques proposed for base stations (BTS) in the Sahel zone, up to 17% of energy savings are realized in CRTV base stations, approximately 24.4% of energy are realized in the base station of Missinguileo, and approximately 14.5% of energy savings are realized in the base station of Maroua market. Albert Ayang, Paul-Salomon Ngohe-Ekam, Bossou Videme, and Jean Temga Copyright © 2016 Albert Ayang et al. All rights reserved. The Economics of Renewable Energy Sources into Electricity Generation in Tanzania Sun, 17 Jul 2016 13:56:44 +0000 The study analyzes the economics of renewable energy sources into electricity generation in Tanzania. Business as usual (BAU) scenario and renewable energy (RE) scenario which enforce a mandatory penetration of renewable energy sources shares into electricity generations were analyzed. The results show total investment cost for the BAU scenario is much lower as compared to RE scenario while operating and maintenance variable costs are higher in BAU scenario. Primary energy supply in BAU scenario is higher tied with less investment costs as compared to RE scenario. Furthermore, the share of renewable energy sources in BAU scenario is insignificant as compared to RE scenario due to mandatory penetration policy imposed. Analysis concludes that there are much higher investments costs in RE scenario accompanied with less operating and variable costs and lower primary energy supply. Sensitivity analysis carried out suggests that regardless of changes in investments cost of coal and CCGT power plants, the penetration of renewable energy technologies was still insignificant. Notwithstanding the weaknesses of renewable energy technologies in terms of the associated higher investments costs, an interesting result is that it is possible to meet future electricity demand based on domestic resources including renewables. Baraka Kichonge, Iddi S. N. Mkilaha, Geoffrey R. John, and Sameer Hameer Copyright © 2016 Baraka Kichonge et al. All rights reserved. Overcapacity as a Barrier to Renewable Energy Deployment: The Spanish Case Tue, 12 Jul 2016 11:54:44 +0000 Renewable energy sources (RES) play a critical role in the low-carbon energy transition. Although there is quite an abundant literature on the barriers to RES, the analysis of the electricity generation overcapacity as a barrier to further RES penetration has received scant attention. This paper tries to cover this gap. Its aim is to analyse the causes and consequences of overcapacity, with a special focus on the impact on RES deployment, using Spain as a case study. It also analyses the policies which may mitigate this problem in both the short and the longer terms. Pablo del Río and Luis Janeiro Copyright © 2016 Pablo del Río and Luis Janeiro. All rights reserved. A Comfort-Aware Energy Efficient HVAC System Based on the Subspace Identification Method Wed, 02 Mar 2016 13:25:55 +0000 A proactive heating method is presented aiming at reducing the energy consumption in a HVAC system while maintaining the thermal comfort of the occupants. The proposed technique fuses time predictions for the zones’ temperatures, based on a deterministic subspace identification method, and zones’ occupancy predictions, based on a mobility model, in a decision scheme that is capable of regulating the balance between the total energy consumed and the total discomfort cost. Simulation results for various occupation-mobility models demonstrate the efficiency of the proposed technique. O. Tsakiridis, D. Sklavounos, E. Zervas, and J. Stonham Copyright © 2016 O. Tsakiridis et al. All rights reserved. Benchmarking of Electricity Distribution Licensees Operating in Sri Lanka Tue, 16 Feb 2016 08:54:21 +0000 Electricity sector regulators are practicing benchmarking of distribution companies to regulate the allowed revenue. Mainly this is carried out based on the relative efficiency scores produced by frontier benchmarking techniques. Some of these techniques, for example, Corrected Ordinary Least Squares method and Stochastic Frontier Analysis, use econometric approach to estimate efficiency scores, while a method like Data Envelopment Analysis uses linear programming. Those relative efficiency scores are later used to calculate the efficiency factor (X-factor) which is a component of the revenue control formula. In electricity distribution industry in Sri Lanka, the allowed revenue for a particular distribution licensee is calculated according to the allowed revenue control formula as specified in the tariff methodology of Public Utilities Commission of Sri Lanka. This control formula contains the X-factor as well, but its effect has not been considered yet; it just kept it zero, since there were no relative benchmarking studies carried out by the utility regulators to decide the actual value of X-factor. This paper focuses on producing a suitable benchmarking methodology by studying prominent benchmarking techniques used in international regulatory regime and by analyzing the applicability of them to Sri Lankan context, where only five Distribution Licensees are operating at present. K. T. M. U. Hemapala and Lilantha Neelawala Copyright © 2016 K. T. M. U. Hemapala and Lilantha Neelawala. All rights reserved. A Thermodynamic Analysis of Two Competing Mid-Sized Oxyfuel Combustion Combined Cycles Sun, 24 Jan 2016 10:00:44 +0000 A comparative analysis of two mid-sized oxyfuel combustion combined cycles is performed. The two cycles are the semiclosed oxyfuel combustion combined cycle (SCOC-CC) and the Graz cycle. In addition, a reference cycle was established as the basis for the analysis of the oxyfuel combustion cycles. A parametric study was conducted where the pressure ratio and the turbine entry temperature were varied. The layout and the design of the SCOC-CC are considerably simpler than the Graz cycle while it achieves the same net efficiency as the Graz cycle. The fact that the efficiencies for the two cycles are close to identical differs from previously reported work. Earlier studies have reported around a 3% points advantage in efficiency for the Graz cycle, which is attributed to the use of a second bottoming cycle. This additional feature is omitted to make the two cycles more comparable in terms of complexity. The Graz cycle has substantially lower pressure ratio at the optimum efficiency and has much higher power density for the gas turbine than both the reference cycle and the SCOC-CC. Egill Thorbergsson and Tomas Grönstedt Copyright © 2016 Egill Thorbergsson and Tomas Grönstedt. All rights reserved. Development of a Cost-Effective Solar/Diesel Independent Power Plant for a Remote Station Tue, 29 Dec 2015 14:09:33 +0000 The paper discusses the design, simulation, and optimization of a solar/diesel hybrid power supply system for a remote station. The design involves determination of the station total energy demand as well as obtaining the station solar radiation data. This information was used to size the components of the hybrid power supply system (HPSS) and to determine its configuration. Specifically, an appropriate software package, HOMER, was used to determine the number of solar panels, deep-cycle batteries, and rating of the inverter that comprise the solar section of the HPSS. A suitable diesel generator was also selected for the HPSS after careful technical and cost analysis of those available in the market. The designed system was simulated using the HOMER software package and the simulation results were used to carry out the optimization of the system. The final design adequately meets the station energy requirement. Based on a life expectancy of twenty-five years, a cost-benefit analysis of the HPSS was carried out. This analysis shows that the HPSS has a lower cost as compared to a conventional diesel generator power supply, thus recommending the HPSS as a more cost-effective solution for this application. Okeolu Samuel Omogoye, Ayoade Benson Ogundare, and Ibrahim Olawale Akanji Copyright © 2015 Okeolu Samuel Omogoye et al. All rights reserved. Briquetting of Charcoal from Sesame Stalk Tue, 25 Aug 2015 09:07:00 +0000 Due to the easy availability of wood in Ethiopia, wood charcoal has been the main source fuel for cooking. This study has been started on sesame stalk biomass briquetting which can potentially solve the health problems and shortage of energy, which consequently can solve deforestation. The result of the data collection shows that, using 30% conversion efficiency of carbonizer, it was found that more than 150,000 tonnes of charcoal can be produced from the available sesame stalk in Humera, a place in north Ethiopia. The clay binders that are mixed with carbonized sesame stalk were found to have 69 liquid limits; thus, the optimum amount of clay that should be added as a binder is 15%, which results in better burning and heat holding capacity and better heating time. The developed briquetting machine has a capacity of producing 60 Kg/hr but the carbonization kiln can only carbonize 3.1 Kg in 2 : 40 hours; hence, it is a bottle neck for the briquette production. The hydrocarbon laboratory analysis showed that the calorific value of the charcoal produced with 15% clay content is 4647.75 Cal/gm and decreases as clay ratio increases and is found to be sufficient energy content for cooking. Alula Gebresas, Haftom Asmelash, Hadush Berhe, and Tsegay Tesfay Copyright © 2015 Alula Gebresas et al. All rights reserved. The Effects of Air Preheating and Fuel/Air Inlet Diameter on the Characteristics of Vortex Flame Thu, 14 May 2015 16:25:08 +0000 The effects of fuel/air inlet diameter as well as air preheating on the flame stability, temperature distribution, pollutant formation, and combustion characteristics of a lab-scaled asymmetric vortex flame have been investigated. A three-dimensional steady-state finite volume solver has been used to solve the governing and energy equations. The solver uses a first-order upwind scheme to discretize the governing equations in the space. The semi-implicit method for pressure linked equations has been applied to couple the pressure to the velocity terms. Several turbulence models were applied to predict the flame temperature and it was found that RNG has given the best results in accordance with the experimental results. The results reveal that the inlet air diameter can enhance the thermal properties and reduce the emission while the inlet fuel diameter has less significant impact. Increasing diameters are accompanied with a pressure drop. It was found that preheating the air and fuel would significantly affect the flame temperature and emission with constant mass flow rate. Mostafa Khaleghi, S. E. Hosseini, M. A. Wahid, and H. A. Mohammed Copyright © 2015 Mostafa Khaleghi et al. All rights reserved. A Subspace Identification Method for Detecting Abnormal Behavior in HVAC Systems Wed, 11 Mar 2015 16:39:02 +0000 A method for the detection of abnormal behavior in HVAC systems is presented. The method combines deterministic subspace identification for each zone independently to create a system model that produces the anticipated zone’s temperature and the sequential test CUSUM algorithm to detect drifts of the rate of change of the difference between the real and the anticipated measurements. Simulation results regarding the detection of infiltration heat losses and the detection of exogenous heat gains such as fire demonstrate the effectiveness of the proposed method. Dimitris Sklavounos, Evangelos Zervas, Odysseas Tsakiridis, and John Stonham Copyright © 2015 Dimitris Sklavounos et al. All rights reserved. Flexible Mode Control of Grid Connected Wind Energy Conversion System Using Wavelet Sat, 28 Feb 2015 07:12:34 +0000 Small wind turbine systems offer services to critical loads during grid faults and also connected back to grid in normal condition. The connection of a wind energy conversion system to the grid requires a robust phase locked loop (PLL) and continuous monitoring of the grid conditions such as overvoltage, undervoltage, overfrequency, underfrequency, and grid outages. This paper describes a flexible control operation to operate a small wind turbine in both stand-alone mode via planned islanding and grid connected mode as well. In particular, a proper monitoring and control algorithm is required for transition between the modes. A wavelet based energy function is used for detection of grid disturbances as well as recovery of grid so that transition between the modes is made. To obtain good power quality LCL filter is used to reduce ripples. PLL is used for synchronization whenever mode changes from stand-alone to grid connected. Simulation results from a 10 kW wind energy conversion system are included to show the usefulness of the proposed methods. The control method is tested by generated gate pulses for single phase bridge inverter using field programmable gate array (FPGA). Bhavna Jain, Sameer Singh, Shailendra Jain, and R. K. Nema Copyright © 2015 Bhavna Jain et al. All rights reserved. Midterm Electricity Market Clearing Price Forecasting Using Two-Stage Multiple Support Vector Machine Thu, 29 Jan 2015 15:29:04 +0000 Currently, there are many techniques available for short-term forecasting of the electricity market clearing price (MCP), but very little work has been done in the area of midterm forecasting of the electricity MCP. The midterm forecasting of the electricity MCP is essential for maintenance scheduling, planning, bilateral contracting, resources reallocation, and budgeting. A two-stage multiple support vector machine (SVM) based midterm forecasting model of the electricity MCP is proposed in this paper. The first stage is utilized to separate the input data into corresponding price zones by using a single SVM. Then, the second stage is applied utilizing four parallel designed SVMs to forecast the electricity price in four different price zones. Compared to the forecasting model using a single SVM, the proposed model showed improved forecasting accuracy in both peak prices and overall system. PJM interconnection data are used to test the proposed model. Xing Yan and Nurul A. Chowdhury Copyright © 2015 Xing Yan and Nurul A. Chowdhury. All rights reserved. Heat Transfer Enhancement and Hydrodynamic Characteristics of Nanofluid in Turbulent Flow Regime Thu, 29 Jan 2015 12:31:36 +0000 Turbulent forced convection of γ-Al2O3/water nanofluid in a concentric double tube heat exchanger has been investigated numerically using mixture two-phase model. Nanofluids are used as coolants flowing in the inner tube while hot pure water flows in outer tube. The studies are conducted for Reynolds numbers ranging from 20,000 to 50,000 and nanoparticle volume fractions of 2, 3, 4, and 6 percent. Results showed that nanofluid has no effects on fully developed length and average heat transfer coefficient enhances with lower slope than wall shear stress. Comparisons with experimental correlation in literature are conducted and good agreement with present numerical study is achieved. Mohammad Nasiri-lohesara Copyright © 2015 Mohammad Nasiri-lohesara. All rights reserved. Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine Sun, 18 Jan 2015 08:35:47 +0000 This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine. Wail Aladayleh and Ali Alahmer Copyright © 2015 Wail Aladayleh and Ali Alahmer. All rights reserved. The Links between Energy Consumption, Financial Development, and Economic Growth in Lebanon: Evidence from Cointegration with Unknown Structural Breaks Sun, 18 Jan 2015 07:31:41 +0000 We investigate the relation between financial development, energy consumption, and economic growth in the economy of Lebanon over the period 2000M2–2010M12. Our findings confirm the existence of cointegration among the variables. The results indicate that financial development and energy consumption contribute to economic growth in Lebanon. The impact of energy consumption on economic growth is positive showing the significance of energy as a main stimulant of economic growth. Financial development is also found to play a vital role in enhancing economic growth. Financial development and economic growth also result in further increase in energy consumption. We offer some policy implications specific to Lebanon considering the recent discovery of large oil and gas reserves in the country and the historical importance of its banking sector which remains a center of Lebanon’s service-oriented economy. Salah Abosedra, Muhammad Shahbaz, and Rashid Sbia Copyright © 2015 Salah Abosedra et al. All rights reserved. Studies on Pyrolysis Kinetic of Newspaper Wastes in a Packed Bed Reactor: Experiments, Modeling, and Product Characterization Thu, 15 Jan 2015 07:06:20 +0000 Newspaper waste was pyrolysed in a 50 mm diameter and 640 mm long reactor placed in a packed bed pyrolyser from 573 K to 1173 K in nitrogen atmosphere to obtain char and pyro-oil. The newspaper sample was also pyrolysed in a thermogravimetric analyser (TGA) under the same experimental conditions. The pyrolysis rate of newspaper was observed to decelerate above 673 K. A deactivation model has been attempted to explain this behaviour. The parameters of kinetic model of the reactions have been determined in the temperature range under study. The kinetic rate constants of volatile and char have been determined in the temperature range under study. The activation energies 25.69 KJ/mol, 27.73 KJ/mol, 20.73 KJ/mol and preexponential factors 7.69 min−1, 8.09 min−1, 0.853 min−1 of all products (solid reactant, volatile, and char) have been determined, respectively. A deactivation model for pyrolysis of newspaper has been developed under the present study. The char and pyro-oil obtained at different pyrolysis temperatures have been characterized. The FT-IR analyses of pyro-oil have been done. The higher heating values of both pyro-products have been determined. Aparna Sarkar, Sudip De Sarkar, Michael Langanki, and Ranjana Chowdhury Copyright © 2015 Aparna Sarkar et al. All rights reserved. Feasibility Analysis and Simulation of Integrated Renewable Energy System for Power Generation: A Hypothetical Study of Rural Health Clinic Thu, 01 Jan 2015 14:21:50 +0000 This paper presents the feasibility analysis and study of integrated renewable energy (IRE) using solar photovoltaic (PV) and wind turbine (WT) system in a hypothetical study of rural health clinic in Borno State, Nigeria. Electrical power consumption and metrology data (such as solar radiation and wind speed) were used for designing and analyzing the integrated renewable energy system. The health clinic facility energy consumption is 19 kWh/day with a 3.4 kW peak demand load. The metrological data was collected from National Aeronautics and Space Administration (NASA) website and used to analyze the performance of electrical generation system using HOMER program. The simulation and optimization results show that the optimal integrated renewable energy system configuration consists of 5 kW PV array, BWC Excel-R 7.5 kW DC wind turbine, 24 unit Surrette 6CS25P battery cycle charging, and a 19 kW AC/DC converter and that the PV power can generate electricity at 9,138 kWh/year while the wind turbine system can generate electricity at 7,490 kWh/year, giving the total electrical generation of the system as 16,628 kWh/year. This would be suitable for deployment of 100% clean energy for uninterruptable power performance in the health clinic. The economics analysis result found that the integrated renewable system has total NPC of 137,139 US Dollar. The results of this research show that, with a low energy health facility, it is possible to meet the entire annual energy demand of a health clinic solely through a stand-alone integrated renewable PV/wind energy supply. Vincent Anayochukwu Ani and Bahijjahtu Abubakar Copyright © 2015 Vincent Anayochukwu Ani and Bahijjahtu Abubakar. All rights reserved. Structural and Thermal Analysis of Asphalt Solar Collector Using Finite Element Method Mon, 15 Dec 2014 08:11:37 +0000 The collection of solar energy using asphalt pavements has got a wide importance in the present energy scenario. Asphalt pavements subjected to solar radiation can reach temperature up to 70°C because of their excellent heat absorbing property. Many working parameters, such as pipe diameter, pipe spacing, pipe depth, pipe arrangement, and flow rate, influence the performance of asphalt solar collector. Existing literature on thermal energy extraction from asphalt pavements is based on the small scale laboratory samples and numerical simulations. In order to design an efficient asphalt solar collector there should be a payoff between the thermal and structural stability of the pavement, so that maximum heat can be absorbed without structural damage due to external load condition. This paper presents a combined thermal and structural analysis of asphalt solar collector using finite element method. Analysis is carried out in different models so as to obtain optimum pipe spacing, pipe diameter, depth, and pipe arrangement under the specified condition. Jinshah Basheer Sheeba and Ajith Krishnan Rohini Copyright © 2014 Jinshah Basheer Sheeba and Ajith Krishnan Rohini. All rights reserved. Does Climate Change Mitigation Activity Affect Crude Oil Prices? Evidence from Dynamic Panel Model Thu, 11 Dec 2014 00:10:16 +0000 This paper empirically investigates how climate change mitigation affects crude oil prices while using carbon intensity as the indicator for climate change mitigation. The relationship between crude oil prices and carbon intensity is estimated using an Arellano and Bond GMM dynamic panel model. This study undertakes a regional-level analysis because of the geographical similarities among the countries in a region. Regions considered for the study are Africa, Asia and Oceania, Central and South America, the EU, the Middle East, and North America. Results show that there is a positive relationship between crude oil prices and carbon intensity, and a 1% change in carbon intensity is expected to cause about 1.6% change in crude oil prices in the short run and 8.4% change in crude oil prices in the long run while the speed of adjustment is 19%. Jude C. Dike Copyright © 2014 Jude C. Dike. All rights reserved. Experimental Investigation of Thermal Characteristics of Kiwira Coal Waste with Rice Husk Blends for Gasification Wed, 19 Nov 2014 11:25:22 +0000 Eminent depletion of fossil fuels and environmental pollution are the key forces driving the implementation cofiring of fossil fuels and biomass. Cogasification as a technology is known to have advantages of low cost, high energy recovery, and environmental friendliness. The performance/efficiency of this energy recovery process substantially depends on thermal properties of the fuel. This paper presents experimental study of thermal behavior of Kiwira coal waste/rice husks blends. Compositions of 0, 20, 40, 60, 80, and 100% weight percentage rice husk were studied using thermogravimetric analyzer at the heating rate of 10 K/min to 1273 K. Specifically, degradation rate, conversion rate, and kinetic parameters have been studied. Thermal stability of coal waste was found to be higher than that of rice husks. In addition, thermal stability of coal waste/rice husk blend was found to decrease with an increase of rice husks. In contrast, both the degradation and devolatilization rates increased with the amount of rice husk. On the other hand, the activation energy dramatically reduced from 131 kJ/mol at 0% rice husks to 75 kJ/mol at 100% rice husks. The reduction of activation energy is advantageous as it can be used to design efficient performance and cost effective cogasification process. Deodatus Kazawadi, Geoffrey R. John, and Cecil K. King’ondu Copyright © 2014 Deodatus Kazawadi et al. All rights reserved. Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete Sun, 16 Nov 2014 00:00:00 +0000 Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient. Kanwaldeep Singh, Sukhpal Singh, and Gurmel Singh Copyright © 2014 Kanwaldeep Singh et al. All rights reserved. Electricity Generation and Energy Cost Estimation of Large-Scale Wind Turbines in Jarandagh, Iran Thu, 13 Nov 2014 12:53:26 +0000 Currently, wind energy utilization is being continuously growing so that it is regarded as a large contender of conventional fossil fuels. This study aimed at evaluating the feasibility of electricity generation using wind energy in Jarandagh situated in Qazvin Province in north-west part of Iran. The potential of wind energy in Jarandagh was investigated by analyzing the measured wind speed data between 2008 and 2009 at 40 m height. The electricity production and economic evaluation of four large-scale wind turbine models for operation at 70 m height were examined. The results showed that Jarandagh enjoys excellent potential for wind energy exploitation in 8 months of the year. The monthly wind power at 70 m height was in the range of 450.28–1661.62 W/m2, and also the annual wind power was 754.40 W/m2. The highest capacity factor was obtained using Suzlon S66/1.25 MW turbine model, while, in terms of electricity generation, Repower MM82/2.05 MW model showed the best performance with total annual energy output of 5705 MWh. The energy cost estimation results convincingly demonstrated that investing on wind farm construction using all nominated turbines is economically feasible and, among all turbines, Suzlon S66/1.25 MW model with energy cost of 0.0357 $/kWh is a better option. Kasra Mohammadi, Ali Mostafaeipour, Yagob Dinpashoh, and Nima Pouya Copyright © 2014 Kasra Mohammadi et al. All rights reserved. A Novel Method for Detecting Abnormal Energy Data in Building Energy Monitoring System Thu, 16 Oct 2014 07:24:26 +0000 This paper presents a novel abnormal data detecting algorithm based on the first order difference method, which could be used to find out outlier in building energy consumption platform real time. The principle and criterion of methodology are discussed in detail. The results show that outlier in cumulative power consumption could be detected by our method. Liang Zhao Copyright © 2014 Liang Zhao. All rights reserved. Study on Calculation Models of Earth-Air Heat Exchanger Systems Thu, 04 Sep 2014 00:00:00 +0000 Modeling is very useful tool in order to predict the effect of the operating parameters like pipe length, radius, depth of burial and air flow rate on the thermal performance and heating/cooling capacity of earth-air heat exchanger (EAHE) systems. Till date many researchers have carried out a number of studies on calculation models for earth-air heat exchanger systems. The analysis of EAHE systems started with the development of one-dimensional models. The two-dimensional models came into practice during the 1990s and were replaced by three-dimensional models in recent years. Latest models are dynamic and technically more advanced which can provide room for all types of grid geometry to produce detailed thermal analysis of EAHE systems. This paper reviews on calculation models of EAHE systems as of the end of March, 2014. Trilok Singh Bisoniya, Anil Kumar, and Prashant Baredar Copyright © 2014 Trilok Singh Bisoniya et al. All rights reserved. Study of Light Harvesting Properties of Different Classes of Metal-Free Organic Dyes in TiO2 Based Dye-Sensitized Solar Cells Mon, 18 Aug 2014 07:07:11 +0000 In dye-sensitized solar cells, the photosensitization of TiO2 thin film semiconductor was accomplished by using different classes of metal-free (fluorone, triarymethane, azo and thiazine based) organic dyes as photosensitizer. The broad electronic absorption spectra of these dyes have been obtained in the visible region due to the presence of chromophoric groups in these dyes. The contribution of these dyes as light harvesting species is seen from the photocurrent action spectrum of the cell. Here, we report the sensitization activity of these dyes in terms of current-potential curve, open-circuit potential, fill factor, IPCE, and overall solar energy conversion efficiency which have been evaluated under 100 mW/cm2 light intensity. The results suggest that dyes based on fluorone and azo groups are promising candidates for high performance, dye-sensitized solar cells because of better anchoring groups (–COOH, –OH, and –) present in these dyes. Better anchorage of dyes to the surface of TiO2 semiconductor helps in charge transfer phenomenon. Ratna Chauhan, Reena Kushwaha, and Lal Bahadur Copyright © 2014 Ratna Chauhan et al. All rights reserved. Analysis of Si/SiGe Heterostructure Solar Cell Wed, 23 Jul 2014 06:38:39 +0000 Sunlight is the largest source of carbon-neutral energy. Large amount of energy, about 4.3 × 1020 J/hr (Lewis, 2005), is radiated because of nuclear fusion reaction by sun, but it is unfortunate that it is not exploited to its maximum level. Various photovoltaic researches are ongoing to find low cost, and highly efficient solar cell to fulfil looming energy crisis around the globe. Thin film solar cell along with enhanced absorption property will be the best, so combination of SiGe alloy is considered. The paper presented here consists of a numerical model of heterostructure solar cell. The research has investigated characteristics such as short circuit current density (), generation rate (), absorption coefficient (α), and open circuit voltage () with optimal Ge concentration. The addition of Ge content to Si layer will affect the property of material and can be calculated with the use of Vegard’s law. Due to this, short circuit current density increases. Ashish Kumar Singh, Jahnvi Tiwari, Ashish Yadav, and Rakesh Kumar Jha Copyright © 2014 Ashish Kumar Singh et al. All rights reserved. Hydropower Production Profiles: Impacts on Capacity Structure, Emissions, and Windfall Profits Mon, 14 Apr 2014 12:30:15 +0000 Production structure in markets with a significant role of hydropower is sensitive to the production profile of hydropower. In this paper we utilize a long-run oriented real-time price based simulation model to analyze through scenarios the impact of different hydropower production profiles on the total annual energy consumed, prices, and capacity structure. We also show the relation between different hydropower production profiles and emissions, costs, and windfall profits. There seems to be no superior scenario under which all socially desirable goals are achieved as there is a clear tradeoff between allowing high windfall profits with highest cost efficiency and achieving the target for lower emissions. Maria Kopsakangas-Savolainen and Rauli Svento Copyright © 2014 Maria Kopsakangas-Savolainen and Rauli Svento. All rights reserved. Microwave Assisted Alkali Pretreatment of Rice Straw for Enhancing Enzymatic Digestibility Tue, 25 Mar 2014 12:09:41 +0000 Rapid industrialization, increasing energy demand, and climate change are the conditions that forced the researchers to develop a clean, efficient, renewable, and sustainable source of energy which has a potential to replace fossil fuels. Ethanol is one of the attractive and suitable renewable energy resources. In present study, effectiveness of microwave pretreatment in combination with sodium hydroxide (NaOH) for increasing enzymatic hydrolysis of rice straw has been investigated and under optimum conditions obtained a maximum reducing sugar (1334.79 µg/mL) through microwave assisted NaOH pretreatment. Chemical composition analysis and scanning electron microscope (SEM) images showed that the removal of lignin, hemicellulose, and silicon content is more in microwave assisted NaOH pretreatment than the blank sample. X-ray diffraction (XRD) analysis revealed that the crystallinity index of rice straw treated with microwave assisted alkali (54.55%) is significantly high as compared to the blank (49.07%). Hence, the present study proves that microwave assisted alkali pretreatment can effectively enhance enzymatic digestibility of rice straw and it is feasible to convert rice straw for bioethanol production. Renu Singh, Sapna Tiwari, Monika Srivastava, and Ashish Shukla Copyright © 2014 Renu Singh et al. All rights reserved. Computer Simulation of the Mass and Energy Balance during Gasification of Sugarcane Bagasse Sun, 16 Mar 2014 11:53:17 +0000 This paper investigated the mass and energy balance of the gasification of sugarcane bagasse using computer simulation. The key parameters and gasifier operating conditions were investigated in order to establish their impact on gas volume and conversion efficiency of the gasification process. The heating value of sugarcane bagasse was measured and found to be 17.8 MJ/kg which was used during calculation of the conversion efficiency of the gasification process. Fuel properties and gasifier design parameters were found to have an impact on conversion efficiency of the gasification process of sugarcane bagasse. The moisture content of sugarcane bagasse was varied by 1.14%, 15%, and 25%, respectively. Optimum conversion efficiency was achieved at low moisture content (1.14%) after computer simulation of the gasification process. The volume of carbon monoxide increased at low moisture content. It was also found that maximum conversion efficiency was achieved at reduced particle diameter (6 cm) and at reduced throat diameter (10 cm) and throat angle (25°), respectively, after these parameters were varied. Temperature of input air was also found to have an impact on the conversion efficiency of the gasification process as conversion efficiency increased slightly with increasing temperature of input air. Anthony Anukam, Sampson Mamphweli, Edson Meyer, and Omobola Okoh Copyright © 2014 Anthony Anukam et al. All rights reserved. Effect of Glass Thickness on Performance of Flat Plate Solar Collectors for Fruits Drying Wed, 12 Mar 2014 06:50:19 +0000 This study aimed at investigating the effect of thickness of glazing material on the performance of flat plate solar collectors. Performance of solar collector is affected by glaze transmittance, absorptance, and reflectance which results into major heat losses in the system. Four solar collector models with different glass thicknesses were designed, constructed, and experimentally tested for their performances. Collectors were both oriented to northsouth direction and tilted to an angle of 10° with the ground toward north direction. The area of each collector model was 0.72 m2 with a depth of 0.15 m. Low iron (extra clear) glass of thicknesses 3 mm, 4 mm, 5 mm, and 6 mm was used as glazing materials. As a control, all collector performances were analysed and compared using a glass of 5 mm thickness and then with glass of different thickness. The results showed that change in glass thickness results into variation in collector efficiency. Collector with 4 mm glass thick gave the best efficiency of 35.4% compared to 27.8% for 6 mm glass thick. However, the use of glass of 4 mm thick needs precautions in handling and during placement to the collector to avoid extra costs due to breakage. Ramadhani Bakari, Rwaichi J. A. Minja, and Karoli N. Njau Copyright © 2014 Ramadhani Bakari et al. All rights reserved.