Abstract: The intermittency is inherently affects the solar energy as the main hot water supplier in renewable systems. Therefore, the storage of the hot water is a vital part of a reliable energy supply system for buildings. Using a proper storage system makes it possible to fill the shortfall or emergency periods. This paper studies the daily thermal performance of a horizontal solar storage tank. It is assumed that the hot water load is similar to the Rand profile and the auxiliary heater is a biomass-fired boiler. The Rand profile assumes a daily hot water of consumption of 120 liters for a family of four. Furthermore, the tank is considered to be fully mixed because its height is relatively low. It means that the temperature in the solar zone of the tank is uniform. This assumption simplifies the analysis because the storage and the load temperature would be the same. The profiles for the storage water temperature, solar fraction and the useful energy gain was obtained and the effects of principal parameters are studied.

Abstract: Increasing of word demand load is caused a new Distributed Generation (DG) enter to power system. One of the most renewable energy is the Wind Energy Conversion System (WECS), which is connected to power system using power electronics interface or directly condition. In this paper an optimal Lead-Lag controller for wind energy conversion systems (WECS) has been developed. The optimization technique is applied to Lead-Lag optimal controller in order to control of the most important types of wind system with doubly Fed Induction Generator is presents. Nonlinear characteristics of wind variations as plant input, wind turbine structure and generator operational behavior demand for high quality optimal controller to ensure both stability and safe performance. Thus, Honey Bee Mating Optimization (HBMO) is used for optimal tuning of Lead-Lag coefficients in order to enhance closed loop system performance. In order to use this algorithm, at first, problem is written as an optimization problem which includes the objective function and constraints, and then to achieve the most desirable controller, HBMO algorithm is applied to solve the problem. In this study, the proposed controller first is applied to two pure mathematical plants, and then the closed loop WECS behavior is discussed in the presence of a major disturbance. Simulation results are done for various loads in time domain, and the results show the efficiency of the proposed controller in contrast to the previous controllers.

Abstract: The computational interface for hydropower plants was developed with Microsoft Visual Studio 2010 and tested using some available data from Jebba hydropower station to validate its functionality due to non availability of data for small hydropower plants which the interface is designed for. Hitherto several other methods have been used in hydropower computation, these methods range from manual computation with the use of pen and paper to the use of Microsoft Excel spreadsheet, some others utilize Visual Basic to commercial software. This interface was designed to compute flow duration values, plant capacity, power duration and the available energy. The program also have the project report feature, where user can view a concise report of the computation, save and print report sheets.

Abstract: Energy is basic need for growth of any country. The world energy demand is increasing so rapidly because of increases in industrialization and population that limited reservoirs will soon be depleted at the current rate of consumption. Both the energy needs and increased environmental consciousness have stimulated the researching of an alternative solution. So an attempted has been made to investigation of biodiesel production using transesterification reaction with solid or heterogeneous catalyst at laboratory scale and to compare the physical properties with the standard biodiesel properties. The selected process parameters are temperature ranged from 318 K to 333 K, molar ratio of methanol to oil from 4:1 to 8:1, mass ratio of catalyst to oil from 3% to 5% and rotation speed at optimum biodiesel yield was produced at 600 rpm.

Abstract: Polymer solar cells have many intrinsic advantages, such as their light weight, flexibility, and low material and manufacturing costs. Recently, polymer tandem solar cells have attracted significant attention due to their potential to achieve higher performance than single cells. Photovoltaic's deal with the conversion of sunlight into electrical energy. Classic photovoltaic solar cells based on inorganic semiconductors have developed considerably [1] since the first realization of a silicon solar cell in 1954 by Chapin, Fuller and Pearson in the Bell labs. [2] Today silicon is still the leading technology on the world market of photovoltaic solar cells, with power conversion efficiencies approaching 15 – 20% for mono-crystalline devices. Though the solar energy industry is heavily subsidized throughout many years, the prices of silicon solar cell based power plants or panels are still not competitive with other conventional combustion techniques – except for several niche products. An approach for lowering the manufacturing costs of solar cells is to use organic materials that can be processed under less demanding conditions. Organic photovoltaic's has been developed for more than 30 years, however, within the last decade the research field gained considerable in momentum [3,4]. The amount of solar energy lighting up Earth's land mass every year is nearly 3,000 times the total amount of annual human energy use. But to compete with energy from fossil fuels, photovoltaic devices must convert sunlight to electricity with a certain measure of efficiency. For polymer-based organic photovoltaic cells, which are far less expensive to manufacture than silicon-based solar cells, scientists have long believed that the key to high efficiencies rests in the purity of the polymer/organic cell's two domains -- acceptor and donor.

Abstract: This paper presents an investigation on finite time thermodynamic evaluation and analysis of a Solar-dish Stirling heat engine. Finite time thermodynamics has been applied to determine the net power output and thermal efficiency of the Stirling system with finite-rate heat transfer, regenerative heat loss, conductive thermal bridging loss and finite regeneration process time. The model investigates the effects of the inlet temperature of the heat source and heat sink, the volumetric ratio of the engine, effectiveness of heat exchangers and heat capacitance rates on the net power output and thermal efficiency of the engine and entropy generation. The thermal efficiency of the cycle corresponding to the magnitude of the maximized power of the engine is evaluated. Finally, sensitivities of results in a variation of the thermal parameters of the engine are studied. The present analysis provides a good theoretical guideline for designing and operating of the Stirling heat engine systems.

Abstract: Catalytic activities of eight sulfonic acid group functionalized ionic liquids in water were compared for the hydrolysis of Sigmacell cellulose (DP ~ 450) in the 150-180°C temperature range by measuring total reducing sugar (TRS) and glucose produced. The catalytic activity of acidic ionic liquids with different cation types decreases in the order imidazolium > pyridinium > triethanol ammonium cation. Among the sulfonic acid group functionalized imidazolium ionic liquids, the catalysts which contain a single imidazolium ion and a flexible linker between sulfonic acid group and the imidazolium ionic liquid core structure are the most active catalysts.

Abstract: Presented here is a bibliographic survey, which covers the work done in the period ranging from 1913 to 2013; towards realization of feasible methods of electricity generation using waste materials. This paper is the outcome of thorough analysis of various literatures available from the earlier research. This paper would be a great source of literature summarized in one paper. This paper would be helpful as a one stop guide, it will introduce the subject to the reviewer, give him an idea of all the previous work done in this field, the chronological research done by some scientist as well as the development in technology/methodology all along the period.

Abstract: Air conditioning of buildings is responsible for a large percentage of the greenhouse and ozone depletion effect, as refrigerant harmful gases are released into the atmosphere from conventional cooling systems. The vapor compression refrigeration is one of the many refrigeration cycles and is the most widely used method for air-conditioning of buildings. On the other hand, solar thermal energy can be used to efficiently cool in the summer. Single, double or triple iterative absorption cooling cycles are used in different solar thermal cooling system designs. Absorption chillers operate with less noise and vibration than compressor-based chillers, but their capital costs are relatively high. In this study, a system is proposed as a combination of the aforementioned systems and the power consumption is minimized using cold thermal energy storage (CTES).

Abstract: The water Savonius rotor is classified as a vertical axis water rotor like the Darrieus, Gyromill or H-rotor. The advancing blade with concave side facing the water flow would experience more drag force than the returning blade, thus forcing the rotor to rotate. In this work, we are interested on the study of the of the internal overlap effect of a water Savonius rotor. The experimental results is developed using a hydraulic test bench. The test bench consists on an intake, a control gate, a penstock, a canalization, a test section, an outflow and a pump. A detailed description of the global characteristics is presented such as power, dynamic torque, power and its coefficients.