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Abstract Sugarcane is a major crop cultivated globally and the residue left over after the crop harvest and extraction of juice is a good biomass source that can be used for the production of several useful chemicals. The sugarcane bagasse is an excellent substrate for the production of various biochemicals and enzymes through fermentation. Now major interest is focused on the utilization of these residue for biofuel production. The sugarcane crop residue is rich in cellulose and hemicellulose, hence it can be used for the production of bioethanol and other liquid transportation fuels. The present review gives a detailed account of the availability of sugarcane residue and various commercially important products that can be produced from this residue. It also provides recent developments in R&D on the bioconversion of sugarcane crop residue for value added products.

Abstract The high viscosity of fish oil leads to problem in pumping and spray characteristics. The inefficient mixing of fish oil with air leads to incomplete combustion. The best way to use fish oil as fuel in compression ignition (CI) engines is to convert it into biodiesel. It can be used in CI engines with very little or no engine modifications. This is because it has properties similar to mineral diesel. Combustion tests for methyl ester of fish oil and its blends with diesel fuel were performed in a kirloskar H394 DI diesel engine, to evaluate fish biodiesel as an alternative fuel for diesel engine, at constant speed of 1500 rpm under variable load conditions. The tests showed no major deviations in diesel engine's combustion as well as no significant changes in the engine performance and reduction of main noxious emissions with the exception on NOx. Overall fish biodiesel showed good combustion properties and environmental benefits.

Access to a reliable source of electricity is a basic need for any community as it can improve the living standards characterized via the improvement of healthcare, education, and the local economy at large. There are two key factors to consider when assessing the appropriateness of a micro-grid system, the cost-effectiveness of the system and the quality of service. The tradeoff between cost and reliability of the system is a major compromise in designing hybrid systems. In this way, optimization of a Hybrid Micro-Grid System (HMGS) is investigated. A hybrid wind/PV system with battery storage and diesel generator is used for this purpose. The power management algorithm is applied to the load, and the Multi-Objective Particle Swarm Optimization (MOPSO) method is used to find the best configuration of the system and for sizing the components. A set of recent hourly wind speed data from three meteorological stations in Iran, namely: Nahavand, Rafsanjan, and Khash, are selected and tested for the optimization of HMGS. Despite design complexity of the aforementioned systems, the results show that the MOPSO optimization model produces appropriate sizing of the components for each location. It is also suggested that the use of HMGS can be considered as a good alternative to promote electrification projects and enhance energy access within remote Iranian areas or other developing countries enjoying the same or similar climatic conditions.

Abstract The latent heat thermal energy storage system (LHTES) utilizes phase change material (PCM) to store energy. The non-uniformity in heat transfer between heat transfer fluid (HTF) and PCM along the height of the widely used vertical cylindrical shell and tube type storage tank causes a reduced thermal performance of the storage. Hence, in the present work, a passive heat transfer enhancement technique is proposed through a novel funnel shaped configuration of the shell and tube LHTES to achieve more uniform temperature distribution in the PCM as compared to the cylindrical shell and tube LHTES. Additionally, longitudinal fins are introduced in the HTF tube further to enhance the heat transfer between HTF and PCM. A numerical model is developed using the enthalpy-porosity technique to analyze the phase change phenomenon. The thermal performance of the funnel LHTES is evaluated using the first and second law of thermodynamics. The funnel LHTES with the lateral shell surface tilting up to a height of 250 mm shows higher melt fraction and energy efficiency by 11.5% and 66.6%, respectively compared to the cylindrical LHTES. The latent heat content of the funnel LHTES with a shell tilt height of 250 mm during the charging and discharging period is improved by 1.72 and 1.11 times, respectively than that of the cylindrical LHTES. A significant improvement in the rate of solidification of PCM during the discharging process is obtained with the funnel LHTES.

Building Integrated Photovoltaic (BIPV) technology is an immerging area of recent development which has a high potential to be implemented in urban areas. PV panels of BIPV system serve as structural elements and are required to be fixed at optimum tilt angle for maximum insolation. For open fields with no obstructions, HDKR (Hay, Davies, Klucher, Reindl) model is employed effectively for calculating the optimum tilt angle. For urban areas, it is required to consider the adverse effect i.e., shading and sky view blocking of building for accurate calculation of optimum tilt angle for determining maximum insolation. This is an attempt to calculate optimum tilt angle of a BIPV panel surrounded by buildings of different heights which are located at different radial distances from panel by employing modified HDKR model. The present mathematical model gives accurate insolation values as it accounts both shading and sky view blocking effects. This sky view blocking effect is expressed by a factor and is calculated by integrating the sky trapped curve plotted for any given tilt angle of the panel. Optimum tilt angle and insolation of BIPV panel are presented for different state capital of India by considering shadow effect because of surrounding buildings.

Abstract Lignocellulosic biomass is considered to be a potential raw material for production of renewable fuels like bioethanol and biodiesel. Cellulose and hemicelluloses constitute major portion of the lignocellulosic biomass. Cellulose can be converted to glucose by hydrolysis and subsequently to ethanol by fermentation. The hemicellulosic portion mostly contains pentose sugars which cannot be utilized by many microorganisms for ethanol production. Acid pretreatment results in separation of a pentose-rich fraction which can be utilized for the production of various high value chemicals. The present study evaluates the utilization of pentose sugars as co-substrate, along with biodiesel industry-generated crude glycerol, for the production of 1,3-propanediol (1,3-PDO). Bioconversion of these low value byproducts into a high value chemical would be an economically advantageous strategy in terms of waste disposal for biorefineries. In this study, the production of 1,3-propanediol from the acid pretreated liquor obtained from rice straw was evaluated using Klebsiella pneumonia. Different carbon sources like pure hexose and pentose sugars, mixed pentose sugar containing acid pretreated liquor (APL) from rice straw and different concentrations of pentose sugars and acid pretreated liquor were evaluated. There is 65% increase in titers from 9.55 g/L to 15.75 g/L using APL as co-substrate. With addition of 0.5% (v/v) APL, 1,3-propanediol production reached 20.88 g/L with 0.69 g/g yield and 0.87 g/L/h productivity. The study comprehensively explains the behavior of Klebsiella pneumoniae strain utilizing pentose rich APL and crude glycerol which enroute to an integrated biorefinery approach.

Abstract Fuel crisis because of dramatic increase in vehicular population and environmental concerns have renewed interest of scientific community to look for alternative fuels of bio-origin such as vegetable oils. Vegetable oils can be produced from forests, vegetable oil crops, and oil bearing biomass materials. Non-edible vegetable oils such as linseed oil, mahua oil, rice bran oil, etc. are potentially effective diesel substitute. Vegetable oils have high-energy content. This study was carried out to investigate the performance and emission characteristics of linseed oil, mahua oil, rice bran oil and linseed oil methyl ester (LOME), in a stationary single cylinder, four-stroke diesel engine and compare it with mineral diesel. The linseed oil, mahua oil, rice bran oil and LOME were blended with diesel in different proportions. Baseline data for diesel fuel was collected. Engine tests were performed using all these blends of linseed, mahua, rice bran, and LOME. Straight vegetable oils posed operational and durability problems when subjected to long-term usage in CI engine. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. However, these problems were not observed for LOME blends. Hence, process of transesterification is found to be an effective method of reducing vegetable oil viscosity and eliminating operational and durability problems. Economic analysis was also done in this study and it is found that use of vegetable oil and its derivative as diesel fuel substitutes has almost similar cost as that of mineral diesel.

Abstract The poor biomass titer and biodiesel productivity under natural sunlight are the major challenges for commercialization of algae-biodiesel. Apart from engineering the nutritional medium and CO2 input strategies, the photobioreactor (PBR) design needs high attention to increase light utilization efficiency. Hence, a novel bubble-driven internal mixer was designed for providing frequent light/dark fluctuation which can improve light utilization efficiency and installed in a bubble-column PBR (BC-PBR) to improve productivities of biomass and biodiesel from Chlorella sp. Without any extra energy requirement (via aeration), in 10 L scale BC-PBR with mixer under simulated sunlight, the productivities of biomass and biodiesel were increased by 13% and 62%, respectively, compared to without mixer. Under natural sunlight, the improvement of biomass productivity was 33% with mixer arrangement and final biomass of 8.6 g L−1 was achieved. Further to improve biodiesel productivity and quality under natural sunlight, the lipid induction was started right after the algae growth of 4.2 g L−1 (at the time of highest biomass productivity, 1.4 g L−1 day−1). Consequently, a very highest biodiesel productivity of 753 mg L−1 day−1 (induction-phase) was achieved. To the best of authors knowledge, this is the first study to report bubble-driven mixer in microalgae cultivation technology.

Abstract The multi-dimensional computational fluid dynamics (CFD) simulation involving in-cylinder flow and combustion have been done to study the effect of soybean methyl ester and piston bowl configuration on performance, combustion and pollutant emissions from a single cylinder diesel engine. The baseline engine configuration consists of a hemispherical piston bowl. The investigation has been conducted for biodiesel blends with diesel and different piston bowl configurations such as Toroidal Re-entrant Combustion Chamber (TRCC), Re-entrant Combustion Chamber (RCC) and baseline Hemispherical Combustion Chamber (HCC) for same bowl volume to have constant compression ratio of 17.5. To simulate the in-cylinder flow and combustion process, AVL FIRE code was performed and experimental results of baseline hemispherical bowl have been used to validate the numerical model. The simulation results show that flow behaviour inside the combustion chamber strongly depends on the piston bowl configuration in diesel engine. The results obtained from the simulation for the fuel blends are compared with that of baseline diesel fuel. The brake specific fuel consumption is higher for biodiesel due to its lower heating value compared to baseline mineral diesel. However, significantly better results were obtained from engine having modified combustion chambers mainly due to better air movement and charge mixing.