Advanced Materials Research Vols. 875-877

Abstract: Previous studies have shown that the solar energy input to the earth system underwent significant decadal variations at individual surface energy budget stations, with a global dimming from 1950s to 1980s, but a global brightening from 1980s to 2000s, and a mixed tendency at different locations thereafter. Here we use a new global gridded solar irradiance dataset to show that the previous results from individual stations represent well the regional means but not the global mean or hemisphere means. The global mean has a decadal variation that is quite different from the individual station results reported in previous studies, which comes from the fact that the southern hemisphere mean has an opposite trend with the northern hemisphere mean. No long-term global dimming trend is found associated with global warming

Abstract: In this paper, the operation of a wind energy conversion system (WECS) incorporating a Double-Fed Induction Generator (DFIG), under various wind speeds and faulty conditions, is investigated through simulation. In this study the simulation of such a system (DFIG-WECS) was held by using the software Matlab/Simulink.. The simulation results are presented and evaluated for the issues of fault diagnosis and identification. More specifically, a DFIG-WECS has been simulated under various wind speeds and when a short-circuit occurs in the back-to-back converter and in the DC link from the point of view of these issues. In this work, it has been concluded that the investigated faults have caused a specific and unique harmonic content in grid, rotor and stator phase currents, which could be used for fault diagnosis and identification.

Abstract: For sake of analyzing influence on load characteristic of urban low voltage distribution network from extensive popularization of charging equipments of electric vehicles, this paper establishes probability density distribution load characteristic model of charging equipment. Taking representative distribution lines and transformer areas with residential and commercial users for instance, summer daily load curves are described and charging load are forecasted, and basic load curves and charging load additional demand curves are peak-valley superimposed according to respective traits, further more, the influence on distribution lines and transformer areas from charging load of electric vehicles with different ages, finally, suggestions are put forward of urban low voltage distribution network planning and charging equipment supervisions.

Abstract: A process of converting a solid carbonaceous fuel into a gaseous energy carrier in presence of a gasifying medium at high temperature is called gasification. The resulting gaseous energy carrier, known as producer gas, is more versatile in its use than the original solid fuel. Gasification is widely considered as a more efficient and less polluting initial thermochemical upstream process of converting biomass to electricity. The objective of this study was to investigate the process of allothermal steam gasification in a fixed-bed downdraft gasifier for improved quality (HHV, high hydrogen content) of the producer gas generated. The study involved thermodynamic equilibrium modeling based on equilibrium approach in which the concentrations of the gaseous components in the producer gas at equilibrium temperature are determined based on balancing the moles in the overall gasification equation. The results obtained suggest that the maximum equilibrium yield of producer gas with high energy density is attained at a gasification temperature of around 820°C and a steam/biomass ratio of 0.825 mol/mol. The equilibrium yield was richer in hydrogen at 52.23%vol, and with a higher heating value of 11.6 MJ/Nm³. Preliminary validation of the model results using experimental data from literature shows a close relationship. The study has further shown the advantage of using steam as a gasifying medium towards the improved quality of the producer gas generated.

Abstract: An information tracking system of the liquefied petroleum gas industry is important to the government in carbon emissions economics. This research applied an information tracking system to the liquefied petroleum gas industry. It also formulated finding a minimization unexpect LPG quantity (Gap), and auto plot the variation by time of a selected firm using html5 techniques, which unexpect LPG quantity (Gap) was over the predefined threshold. Through a web-structure dynamic tracking system, a manager can easily access the information of unexpect LPG quantity (Gap) firms. Future research suggests expanding this research to physical tank constraints calculation.

Abstract: In order to study on stability of hydroelectric generating set under isolated grid, taking hydraulic, mechanical, and electrical system into consideration to build the mathematical model. This paper has researched on the main governor parameters sensitivity in the small fluctuations transition process of complex hydropower station under isolated grid. According to the simulated results, KP or KI increases, or KD decreases appropriately, governor quality of small fluctuation transition process will be better. The influence caused by KD is the most obvious of the three.

Abstract: Combustion performance from the use of hydrogen generated through chemical activity between aluminum and hydrochloric acid that can be applied as an alternative fuel source for internal combustion engine needs is the aim of this paper. Applications of a mixture of hydrogen with petrol can be used to increase the combustion performance especially on the effect of sfc. Sfc is the parameter used in stoichiometric ratio for the combustion process. The methodology includes the production process of hydrogen, interpretation of reaction rates and the effect on specific fuel consumption (sfc) for internal combustion engine. This results showed 0.7412 mole of hydrogen can be generated through the chemical reaction between 20 grams of aluminium with 250 ml of hydrochloric acid or 1 kg of aluminium can produce 37.06 moles which is equivalent to 108 grams hydrogen. Fuel economy of each load test was 6.5% (L0), 18.5% (L1) and 30% (L2) in grams per kilowatt hour. The rate used in each test load was 100 g/kWh (L0), 80.77 g/kWh (L1), and 112 g/kWh (L2) compared to petrol of 107 g/kWh (L0), 99.23 g/kWh (L1) and 162 g/kWh (L2). Results from the combustion of petrol, air and hydrogen in proportion of 100 g/kWh, 80.77 g/kWh and 112 g/kWh was able to improve the quality of combustion compared to the normal fuel consumption. The total use of sfc achieved 20.3% savings in grams per kilowatt hour for the engine (G + H₂) with an average value of 98 g/kWh compared to the engine (G) with an average value of 123 g/kWh.

Abstract: The Residential sector in Brazil is responsible for 26% of energy consumption for illumination, refrigeration and heating, because of this there is a necessity to project in a correct way the openings and choose better materials for construction, targeting the energy rationalization. This article describes the development of a new model that uses a method where openings are represented by single glass and double glass. The model is based on a healthy balance equations purely theoretical and empirical data. Simplified equations are derived through a synthesis of the measured data obtained from meteorological stations, as well as the literature. The implementation of the model in a design tool integrated naturally lit buildings is discussed in this article, to better punctuate the requirements of comfort and energy efficiency in architecture and engineering. Assumes significant importance in studies of heatstroke buildings, aiming to guide the professionals through the process of architectural design, preliminary study and detail of construction elements. It was used a method of degree-days for an assessment of the energy performance of a building showed that the design of the architectural design should always be considered the materials used and the size of the openings. The energy performance was obtained through the model, considering the location of the building in the city of Curitiba, Foz do Iguaçu, Londrina and Cascavel - PR. Obtained climatic data of these locations and in a second step, it was obtained the coefficient of total heat loss in the building pre-established so evaluating the thermal comfort and energy performance. It was observed that heating degree days in winter are of 77.78 to Curitiba the base temperature of 14 ° C and cooling degree days in winter 30.17. For Curitiba lower air exchange, the lower the energy consumption for heating and thus the higher the intake, the greater exchange of air. This means that the more openings in buildings in Curitiba, and are installed to the east side, they may be higher because the glass added to the geometry of architectural spaces will cause the environment conserve energy.

Abstract: Despite the recent advances in space technologies, electrical power systems still are challenging researchers developing small satellites for low earth orbit use. In order to supply their subsystems, these satellites can only use the power stored on board from solar energy. Therefore, the electrical power system should ensure a maximum exploitation of energy sources and optimize the distribution of the available electrical power. In this context, Research Group of Intelligent Machines Laboratory in Tunisia developed a new intelligent electrical power subsystem to be used for pico satellites. This subsystem is based on fuzzy logic allowing a faster energy storage and better and efficient energy distribution. The intelligent electrical power subsystem was successfully integrated in ERPSat-1 pico satellite. In addition, the simulation has shown better results compared to other used methods in the previous electrical power systems used for small satellites.

Abstract: Electric vehicle charging station provides power supply for electric vehicles running, and it is the most important supporting infrastructure of electric vehicles. The article analyses three modes of electric vehicle charging station charging methods, discusses the advantages and disadvantages of each model, gives the developing trend of the pattern of the operation of electric vehicles, and provides some effective suggestions for electric vehicle charging station for the future.