Advanced Materials Research Vol. 768

Abstract: This paper deals with the control of permanent-magnet synchronous generator (PMSG) where the rotor position and speed estimation is essentially required to operate it on maximum power points. Here, Adaptive Neuro Fuzzy Inference System Technique (ANFIS) is used to estimate the speed and position of PMSG, where an ANFIS-system is continuously tuned with actual value of PMSG. The proposed system consists of a back-to-back converter, where PMSG side converter has MPPT output and another one is used for grid synchronization. The generator side ANFIS estimator is used to estimate the rotor position and speed accurately over a wide speed range. The purpose of grid side ANFIS estimator is to control and manage the inverter according to the load demand and storage of electricity in battery which is coupled with dc link of back to back converter respectively. The stored electricity in battery is fed back to grid when needed. The proposed system is designed in MATLAB/SIMULINK.

Abstract: The objective of this work is to make a study of the photovoltaic generator and converters used to supply a brushless DC machine actuating a centrifugal pump. This will be carried out by modeling and simulation of the various stages that constitute the overall system, which includes the photovoltaic source, the maximum power point tracker and the three-phase inverter with the space vector modulation scheme The simulation has been carried out using MatLab-Simulink and the results are presented for different operating conditions.

Abstract: This paper describes a laboratory model of a wind energy conversion scheme (WECS) using conventional cage rotor type induction motor of 3Hp, 3-Ø, 415V, 4.9A, 1440 rpm. A 220V, 20A separately excited motor coupled with the induction motor emulates the wind turbine characteristics. A 3-Ø, 415 V capacitor bank of 150μF is connected in each phase across the stator terminals of the machine for its self-excitation. As soon as rotor speed exceeds synchronous speed of the machine, it will generate electrical power and reach its rated value. This arrangement is called as self-excited induction generator (SEIG). To control the frequency of generated voltage, load-balancing technique is considered by using a three-phase diode rectifier powering to an additional load (dump load) through a d.c chopper circuit. Static reactive volt-ampere compensator (STATCOM) is used to mitigate the load reactive power requirement indeed magnetic reactance changes in the machine. Owing to cost optimization of STATCOM, additional reactor is connected across the stator terminals of the SEIG. Simulation study is completed using power system toolbox Matlab / Simulink version9.0. Experimental and simulation results are presented.

Abstract: Biodiesel usage is gradually becoming popular around the world because of their low environmental pollutants. The properties of biodiesel and its blend were compared with that of diesel. The study reviled that the performance of the engine with 20% PPME gives better performance than that of diesel at part load. The performance for other blends where slightly lesser than that that of diesel. The BSFC of biodiesel was slightly higher than that of diesel due to its lower calorific value. CO and HC emissions were found lesser for biodiesel and its blend compared with that of diesel, whereas NOx emission was found somewhat higher than that of diesel.

Abstract: For many decades all major conservation bodies have realized the need to conserve our valuable fuel and power sources. The increased level of consumption of fuel and power results in carbon-di-oxide emissions to environment which results in the depletion of ozone layer leading to global warming. As a result, many ways of utilizing renewable fuel and power sources are developing with solar energy and waste heat recovery applications. Most of the process and industries have large capacity Diesel Generating (DG) set. The exhaust gas of such a DG set carries a lot of heat and it goes waste if it is not utilized properly. Energy recovery from engine exhaust is one of the energy saving methods in engines. By using energy recovery techniques, waste heat energy can be saved, emissions can be reduced and thermal efficiency of the engine is increased. This paper discusses about the exhaust gas energy recovery from engine exhaust using Rankine cycle and thermodynamic properties of the working fluids. The heat energy recovered from the engine exhaust can be utilized for various sources.

Abstract: Heating of water for domestic purpose by making use of solar energy is essential and it is one of the effective ways of utilizing solar energy. Initial cost of solar water heating (SWH) system is high, but the operation cost is zero. This paper discusses on improving the performance of a flat plate solar energy collector by changing the design parameters of the number of riser tubes and the arrangement of riser tubes in zig-zag pattern from the existing flat plate collector system (FPC) and using the different working nanoparticles with base fluids like aluminium oxide mixed with water. Experiments were conducted using copper tube in headers and risers with two different configurations and maintain the same dimensions. The performance comparison was made for all the two types of collectors in closed loop. The performance shows that the efficiency of FPC with zig-zag arrangement of tubes (Z-Configuration) is higher than that of conventional FPC. Thus the newly presented FPCs system produces higher efficiency than the existing conventional flat plate collector system.

Abstract: Alternative fuels for diesel engines are becoming important due to the decrease of petroleum reservoirs and the increase of environment pollution problems. The biodiesel is technically competitive with conventional petroleum-derived diesel fuel and requires no changes in the fuel distribution system. Injection process of biodiesel influences the atomization and dispersion of fuel in the combustion chamber. In diesel Engine different tests have been performed to improve the efficiency in cycle, power, less emission, speed, etc. There are various methods of visualizing the combustion chamber in a Diesel engine. For visualizing spray characteristics of combustion chamber in Diesel engine the window of 10mm diameter hole, transparent quartz glass materials are used, which can with-stand 1500°C temperature and pressure of about 1000 bar and engine is hand cranked for conducting the experiments. Spray characteristics of palm oil methyl ester (POME) and diesel were studied experimentally. Spray penetration and spray angle were measured in a combustion chamber of DI diesel engine by employing high definition video camera and image processing technique. The study shows the POME gives longer spray tip penetration and spray angle are smaller than those of diesel fuels. This is due to the viscosity and density of biodiesel.

Abstract: The increasing industrialization and motorization of the world has led to a steep rise for the demand of petroleum-based fuels. Petroleum based fuels are obtained from limited reserves highly concentrated in certain regions of the world i.e. those countries that lack these resources are facing energy crisis. Hence it is necessary to look for alternative fuels which can be produced from resources available locally within the country such as biodiesel, alcohol and vegetable oil. The biodiesel is technically competitive with conventional petroleum derived diesel fuel and requires no changes in the fuel distribution system. For this reason and its biodegradability, use of biodiesel is considered a good alternative of fossil fuels. Injection process of biodiesel influences the atomization and dispersion of fuel in the combustion chamber. In this research work the influence of biodiesel on injection process and their impact on the air-fuel mixture preparation are studied. Spray characteristics of biodiesel (Jatropha oil) and diesel under various injection pressures were studied experimentally. Spray penetration and spray angle were measured in a spray vessel using a high speed video camera. The study shows the biodiesel gives longer spray tip penetration and spray angle are smaller than those of diesel fuels. The parameters like break up time and break up velocity were for biodiesel and diesel at various injection pressures. It was found that breakup time for biodiesel increases and breakup velocity decreases. Breakup velocity of biodiesel is less than diesel, this is due to higher sound velocity, density, viscosity and bulk modulus of biodiesel. High viscosity fuel suppresses the instabilities required for fuel jet to breakup and thus delays atomization and reduces fuel losses during injection. With the increase in fuel injection pressure, the breakup time for biodiesel is more than diesel, this is due its larger surface area of the spray and larger mixing time of biodiesel than diesel.

Abstract: In advancing modern world, the recent technological advancements especially in the field of automobile and industrial sectors have created a hike in energy demand. The fossil fuels, which are the main sources of energy, are non-renewable. Due to excessive exploitation, the fossil fuels are depleting rapidly and have created a need for alternate fuel. The researches have been conducted on various biodiesel worldwide to acquire an efficient biodiesel. The biodiesel of pongamia pinnata is one such feasible alternative since the tropical climatic conditions of Asia supports its large cultivation. This paper investigates the characteristics of engine fuelled by pongamia pinnata biodiesel. The use of biodiesel as primary fuel causes reduction in the engine performance. The performance of biodiesel fuelled engine is improved by the induction of hydrogen into air intake manifold. The induction of hydrogen increases the brake thermal efficiency by 3.41%. The hydrogen induction increases NO_X in the exhaust. In order to reduce the NO_X emission, Diethyl ether is injected in to the engine at constant rate of 0.7 gm/min. The DEE injection reduces the NO_X and also increases the engine performance to a significant level.

Abstract: Our environment is majorly polluted by the release of hazardous gases into the atmosphere mainly from automobiles. The day-by-day increase in the usage of automobiles on the roads and decrease in the natural fuel source stresses engineers and scientists to develop engines with better fuel efficiency and reduced negative impact on environment. This could be feasible by controlling the engine tribological parameter using composite material. Clearly it is by reducing the weight and friction in the engine by applying suitable composite material and thereby reducing the wear, it can easily control the hazardous emissions to the environment and thereby keeping the environment safe.