With the objective of exploring the potential of bioethanol production from lignocellulosic wastes from major agro-based industries in Nepal, four types of major industries using raw materials from agriculture are selected as sources of lignocellulosic residues. They include a sugar industry, a paper industry, a tobacco industry, and a beer industry. Data from secondary/primary sources were used to record organic residues from these industries and estimates were made of potential production of bioethanol from them. About 494892.263 tons of dry bagasse could be produced if the total production of sugarcane in Nepal is taken to the sugar industry which means that about 138569.833 KL of bioethanol could be produced (in the year 2011/12). Similarly, the dry biomass residue produced from the paper mill is 86.668 ton/year that could produce 24.267 KL of bioethanol. The lignocellulosic residue from tobacco field in Nepal is approximately 18.826 ton/year that has potential to produce 5.836 KL of bioethanol. The dry biomass residue produced in beer industry amounts to 155.0596 ton/year that can yield about 63.5744 KL of bioethanol. It is estimated that about 57,841.3754 KL of bioethanol could be produced when these residues are fully utilized in producing bioethanol. If E10 is used in total import of petrol, about 20246.7 KL of bioethanol could be utilized, and the rest 37,594.6754 KL of bioethanol could be utilized for many other purposes.
The implantation of wind turbines generally follows a wind potential study which is made using specific numerical tools; the generated expenses are only acceptable for great projects. The purpose of the present paper is to propose a simplified methodology for the evaluation of the wind potential, following three successive steps for the determination of (i) the mean velocity, either directly or by the use of the most occurrence velocity (MOV); (ii) the velocity distribution coming from the single knowledge of the mean velocity by the use of a Rayleigh distribution and a Davenport-Harris law; (iii) an appropriate approximation of the characteristic curve of the turbine, coming from only two technical data. These last two steps allow calculating directly the electric delivered energy for the considered wind turbine. This methodology, called the SWEPT approach, can be easily implemented in a single worksheet. The results returned by the SWEPT tool are of the same order of magnitude than those given by the classical commercial tools. Moreover, everybody, even a “neophyte,” can use this methodology to obtain a first estimation of the wind potential of a site considering a given wind turbine, on the basis of very few general data.
The numerical study of the natural convection loss occurring from cylindrical solar cavity receivers is reported in this communication. These cavity receivers can be used with solar dish concentrators for process heat applications at medium temperature levels. Three cylindrical cavity receivers of diameter 0.2, 0.3, and 0.4 m with aspect ratio equal to one and opening ratios of 1 and 0.5 are used for the analysis. Fluent CFD software is used for the analysis of the three-dimensional (3D) receiver models. In this study the receiver tubes within the cylindrical cavity are modeled as a helical coil similar to those existing in actual systems. The flow of the working fluid within the helical coil is also modeled. The simulations are performed for fluid inlet temperatures of 150°C and 250°C and for receiver inclination angles of 0 (sideways-facing cavity), 30, 45, 60, and 90 degree (vertically downward-facing receiver). It is found that the convective loss increases with increasing mean fluid temperature and decreases with, increase in receiver inclination. The convective loss is found to increase with, opening ratio. These observations are true for all cavity receivers analysed here. A Nusselt number correlation involving Rayleigh numbers, receiver inclinations, and opening ratios is proposed for the convective loss.
A research on production of biodiesel from lipid of phytoplankton Porphyridium cruentum through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extraction method using ethanol 96%, while biodiesel synthesis was carried out by transesterification reaction using methanol and KOH catalyst under sonication. Weight of biodiesel yield per biomass Porphyridium cruentum is 40,27%. Characterization of biodiesel was well carried out in terms of physical properties which are density and viscosity and chemical properties which are FFA content, saponification value, and iodine value. These values meet the American Society for Testing and Materials (ASTM D6751) standard levels, except for the density value which was 0.9461 g·cm−3 and the FFA content which was 4.6671%.
Microgrid becomes one of the key spot in research on distributed energy system. Since the definition of the microgrid is paradigm by the first time, investigation in this area is growing continuously and there are numerous research projects in this moment over the world. The main objective of this paper is to make a comprehensive survey focused on the power quality improvement in microgrid. The increased infiltration of nonlinear loads and power electronic interfaced distribution generation systems creates power quality issues in the distributed power system. Whereas major power quality problems are voltage unbalance, frequency regulation and harmonic elimination are discussed.
This study presents a novel search algorithm of maximum power point tracking for photovoltaic power generation systems. The I-V characteristics and the P-V power output under specific irradiation and temperature conditions are simulated. The performance of the algorithm under fully shaded and sudden partially shaded conditions as well as variable insulations levels is investigated. The developed algorithm performs a wide-range search in order to detect rapidly changing weather conditions, and keeps the simulated stand-alone or grid-connected systems continuously operating close to the maximum power point. The performance of the developed algorithm, under extremely changing environmental conditions, is found to be superior compared to that of other conventional algorithms. The results of this study show that, under uniform radiations conditions, the developed algorithm takes only half of the time required by the Perturbation and Observe algorithms to reach maximum power point MMP. Furthermore, when PV is subjected to sudden partial shading conditions, the algorithm rapidly detects these changes and reaches the new MMP in less than a second.
This paper deals with the Maximum Power Point Tracking (MPPT) for photovoltaic energy system. It includes photovoltaic array panel, DC/DC converter, and load. The operating point for photovoltaic energy system depends on climatic parameters and load. For each temperature and irradiation pair, there exists only one optimal operating point which corresponds to the maximum power transmitted to the load. The photovoltaic energy system is described by nonlinear equations. It is transformed into an augmented system which is described with a Takagi-Sugeno (T-S) fuzzy model. The proposed MPPT algorithm which permits transfering the maximum power from the panel to the load is based on Parallel Distributed Compensation method (PDC). The control parameters have been computed based on Linear Matrix Inequalities tools (LMI). The Lyapunov approach has been used to prove the stability of the system. Some reliable simulation results are provided to check the efficiency of the proposed algorithm.
Phase change material (PCM) based thermal energy storage (TES) systems are gaining increasing importance in recent years in order to reduce the gap between energy supply and demand in solar thermal applications. The present work investigates the effect of PCM capsule material on the performance of TES system during charging and discharging processes. The TES unit contains paraffin as PCM filled in spherical capsules and is integrated with flat plate solar collector. Water is used as sensible heat material as well as heat transfer fluid (HTF). The PCM capsules are of 68 mm diameter and are made using three different materials, namely, (i) high density polyethylene (HDPE), (ii) aluminum (Al), and (iii) mild steel (MS). The experimental investigation showed that the charging and recovery of stored energy are less affected by the spherical capsules material. The variables, like charging time and discharging quantity, are varied around 5% for the different capsule materials. Even though aluminum thermal conductivity is much higher than HDPE and mild steel, its influence on the performance of TES system is very low due to the very high internal heat resistance of PCM material stored in the spherical capsules.
A photovoltaic-thermal water heating system is a hybrid energy conversion device transforming the incident solar radiation to yield electrical energy and thermal energy. Plane reflectors are found to be a convenient option for enhancing the solar radiation incident on the collector plane. The present work investigates the performance of a photovoltaic-thermal water heater integrated with a plane reflector mounted on the top edge of the collector for the tropical climate of Calicut (11.25°N, 75.78°E). Performance testing of the system has been carried out for the winter season of the location. The variations in thermal and electrical output are studied for various inclination angles of the reflector. The system performance is evaluated on the basis of system energy efficiency and exergetic efficiency. It is observed that there is a significant enhancement in the thermal and electrical output of the system with the integration of the reflector as compared to the system without the reflector. For the present system, the reflector tilt angle in the range of 85–100° has been found to be suitable in terms of enhanced system output and exergetic efficiency for the winter conditions of Calicut.
Biodiesel from sunflower oil offers a potential as an alternative to petroleum-based diesel fuel and must be evaluated in terms of the resulting engine performance and exhaust emissions. Two diesel engines rated at 14.2 kW (small) and 60 kW (large) were operated on pure sunflower methyl ester (SFME) and its blends with a reference diesel (REFDIESEL). Results showed that less power and torque were delivered by both the small and large engines when ran on pure SFME than on REFDIESEL, while brake-specific fuel consumption (BSFC) was found to be higher in pure SFME. Blends of SFME with REFDIESEL (B5 and B20) showed negligible power loss and similar BSFC with the REFDIESEL. Higher concentrations of nitrogen oxides (), carbon dioxide (CO2), and total hydrocarbons (THC) in the exhaust emissions were observed for both pure SFME and SFME-REFDIESEL fuel blends. Comparison with soybean methyl ester indicates similar engine performance. Thus, blends of SFME with diesel may be used as a supplemental fuel for steady-state nonroad diesel engines to take advantage of the lubricity of biodiesel as well as contributing to the goal of lowering the dependence to petroleum diesel.
The objective of the present research work is to design user friendly solar cooker which can be commercialized too. This cooker is designed, developed, and tested in our laboratory. The basic principle is to incorporate heating into material by photovoltaic effect and thermal treatment. Different temperatures inside the solar cooker were measured and profile of solar cooker was studied for several days during April, May, and June 2012. It is observed that the designed cooker needs the boosting of only 30 watt power which is generated by a small solar panel connected with it. Heater connected with it can be powered by a solar panel of 75 watt. This boosting can reduce the cooking time. Different recipes were prepared to test its actual performance.
Variations in photovoltaic (PV) module current-voltage curves result in a power loss in PV arrays often referred to as mismatch loss (MML). As a means of reducing MML, newly fabricated PV modules are sorted to meet a set tolerance for variation in overall maximum power output with respect to a given module’s rated power. Starting with flash test data sets for two different polycrystalline PV modules and a simulated sorting procedure, Monte Carlo techniques were used to generate a large number of artificial PV arrays. The MMLs for each of these arrays were then calculated to assess the sorting procedure’s ability to reduce MML. Overall MMLs were quite small (0.001–0.01%). Sorting by Imp resulted in the most consistent MML reductions. Sorting by Vmp yielded insignificant results. Sorting by Pmp yielded significant MML reduction in only one of the two PV module data sets. Analysis was conducted to quantify if additional sorting on top of what both manufacturers had already done would make economic sense. Based on high level economic analysis, it appears that additional sorting yields little economic gain; however, this is highly dependent upon manufacturer sorting cost.
Diamond-like carbon films were electrodeposited on n-Si substrate to realize an n-Si/DLC PV structure. The films thus obtained were characterized by FESEM, XPS, FTIR, and Raman studies. Solar cell characteristics were also investigated critically. Maximum efficiency of 3.7% was obtained for the best n-Si(100)/DLC structure. Carrier life time was obtained from Voc decay measurement. It was observed that photoinduced charge separation in n-Si(100)/DLC structure was associated with an increase in the dielectric constant and a decrease in the device resistance. The process, being reproducible, cheap, and scalable, involving significantly less process steps, is likely to usher a new hope to the current competitive scenario of PV technology.
The standard air density of 1.225 kg m −3 is often used in determining the energy output of a wind turbine although the energy output is dependent on a site's air density. By using measurements of temperature, dew-point temperature, and pressure, we calculate the monthly air density of moist tropical climates at two sites in the small-island state of Trinidad and Tobago. In addition, we calculate the energy output of a BOREAS 30 kW small wind turbine using the 10 m level wind speed distribution extrapolated to hub height. The average air densities at Crown Point and Piarco were 1.156 kg m −3 and 1.159 kg m −3 , respectively, and monthly air densities at both sites were at most 6% less than standard air density. The difference in energy output of the BOREAS 30 kW calculated using standard air density over that using the local site's air density could provide electrical energy for the continuous monthly operation of 6 light bulbs rated at 50 W at Crown Point and 4 light bulbs at Piarco. Thus, communities interested in implementing wind turbine technologies must use the local air density of the site when sizing a wind turbine system for its needs.
This paper presents new improvements and real result of a stand-alone photovoltaic power system for LED lighting that was developed previously. The actual system, during day, charges a lead acid battery using MPPT algorithm for power transfer optimization, and, during night, it supervises battery discharge and controls the current in the power LED array. The improvements are in hardware and software. The hardware was simplified using only one DC/DC converter and only one microcontroller making it more efficient. The system board uses an ATMEL ATTINY861V microcontroller, a single-ended primary inductance converter (SEPIC), and sensors to read input and output voltages and currents to control all system. The software improvements are made in the battery charging algorithm, battery discharging algorithm, and in current control of the power LED array adjusting the light intensity. Moreover, results are presented showing the balance of energy in a period of 24 hours: first results of the MPPT algorithm in bulk battery charge phase and then the over battery charge phase, both in a sunny day. The power LED current control results are also presented showing a very small error. It turns off at 00 : 00 at each day to reduce the waste of energy. Finally, the balance of energy is studied and presented to help the right projection of the PV power panel needed and the necessary battery capacity.
The use of liquefied petroleum gas (LPG) is experimented with to improve the performance of a dual fuel compression ignition (CI) engine running on Karanja oil methyl ester (KOME) blends. Diesel is used as a reference fuel for the dual fuel engine results. During the experimentation, the engine performance is measured in terms of brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC), and exhaust emission is measured in terms of carbon monoxide (CO), hydrocarbon (HC), and oxides of nitrogen (). Dual fuel engine with LPG showed a reduction in and smoke emission; however, it suffers from high HC and CO emission, particularly, at lower loads due to poor ignition. Comparison of performance and emissions is done for diesel and blends of KOME. Results showed that using KOME blends (10% and 20%) has improved the CI engine performance with a reduction in HC and CO emissions.
Torrefaction is a mild form of pyrolysis that, when applied to biomass, has the effect of improving the energy density of biomass-derived solid fuels. In this study, thermogravimetric analysis (coupled with mass spectrometry) was applied to two biomass fuels (pine wood and white maize ear) to investigate a potential representative torrefaction thermal treatment process. The mass loss from the torrefaction process was indicative of emission of aliphatic hydrocarbons, evidenced by mass spectroscopic data and it is evident that optimal torrefaction conditions are determined by the type of biomass to which torrefaction processing is applied.
The present rate of economic growth is unsustainable without saving of fossil energy like crude oil, natural gas, or coal. There are many alternatives to fossil energy such as biomass, hydropower, and wind energy. Also, suitable waste management strategy is another important aspect. Development and modernization have brought about a huge increase in the production of all kinds of commodities, which indirectly generate waste. Plastics have been one of the materials because of their wide range of applications due to versatility and relatively low cost. The paper presents the current scenario of the plastic consumption. The aim is to provide the reader with an in depth analysis regarding the recycling techniques of plastic solid waste (PSW). Recycling can be divided into four categories: primary, secondary, tertiary, and quaternary. As calorific value of the plastics is comparable to that of fuel, so production of fuel would be a better alternative. So the methods of converting plastic into fuel, specially pyrolysis and catalytic degradation, are discussed in detail and a brief idea about the gasification is also included. Thus, we attempt to address the problem of plastic waste disposal and shortage of conventional fuel and thereby help in promotion of sustainable environment.
Bioethanol as a fossil fuel additive to decrease environmental pollution and reduce the stress of the decline in crude oil availability is becoming increasingly popular. This study aimed to evaluate the concentration of bioethanol obtainable from fermenting cashew apple juice by the microorganism Saccharomyces cerevisiae Y2084 and Vin13. The fermentation conditions were as follows: initial sugar = 100 g/L, pH = 4.50, agitation = 150 rpm, temperatures = 30°C (Y2084) and 20°C (Vin13), oxygen saturation = 0% or 50%, and yeast inoculum concentration = ~8.00 Log CFU/mL. The maximum ethanol concentration achieved by Y2084 was 65.00 g/L. At 50% oxygen the fermentation time was 5 days, whilst at 0% oxygen the fermentation time was 11 days for Y2084. The maximum ethanol concentration achieved by Vin13 was 68.00 g/L. This concentration was obtained at 50% oxygen, and the fermentation time was 2 days. At 0% oxygen, Vin13 produced 31.00 g/L of ethanol within 2 days. Both yeast strains produced a higher glycerol concentration at 0% oxygen. Yeast viability counts showed a decrease at 0% oxygen and an increase at 50% oxygen of both yeast stains. Other analyses included measurement of carbon dioxide and oxygen gases, process monitoring of the fermentation conditions, and total organic carbon. Gas analysis showed that carbon dioxide increased in conjunction with ethanol production and oxygen decreased. Process monitoring depicted changes and stability of fermentation parameters during the process. Total organic carbon analysis revealed that aerobic fermentation (50% oxygen) was a more efficient process as a higher carbon recovery (95%) was achieved.
A comparison between some regression correlations for predicting the global solar radiation received on a horizontal plane has been processed. Seven models for estimating the global solar radiation from sunshine duration and two meteorological parameters (air temperature and relative humidity) are presented. The root mean square error (RMSE), mean bias error (MBE), correlation coefficient (CC), and percentage error () have been also computed to test the accuracy of the proposed models. Comparisons between the measured and the calculated values have been made. The results obtained show that the linear and quadratic models are the most suitable for estimating the global solar radiation from sunshine duration, and for the models based on meteorological parameters, Abdalla and Ojosu's models give the best performance with a CC of 0.898 and 0.892, respectively.
