Parabolic Sun Tracking Solar Distillation System

The main aim of the present study is to draw attention to the possibilities and to the measures of appropriate utilization of renewable energy to achieve what is called “water self-sufficient” for arid regions in Jordan. Also to put efforts of increasing the use of renewable energy sources to lower cost of potable water pumping and gives more economical benefits. Another aim of the current research is to utilize the new control algorithm and the developed computer capabilities in the field of sun tracking in order to improve the efficiency of solar distillers. The new tracking method is utilized for water distillation taking advantage of high possible concentration of parabolic trough collector to reach high levels of daily yield per square meter. The present research utilizes the techniques of image processing to catch the core of the sun as the target, also used artificial intelligence techniques to predict the sun position in abnormal conditions (i.e. cloudy, dusty, rainy). The results of sun tracking using image processing found to be accurate and reliable according to the self monitoring of the focus point validated by the solar radiation results. Water distillation yield shows high percentage output of distillate of about 65% of water supplied to distiller. Mechanical design was tested for high ability to withstand the extra loading. It was found that the output yield reached to noticeable levels, because of the use of the parabolic collector that promoted the solar still efficiency.

Multi Criteria Evaluation Model of Renewable Energy Power Plants Based on ELECTRE Method

The feasibility evaluation of renewable energy power plants from multi criteria is necessary to save energy, protect environment and develop technology. This paper employs the improved elimination et choice translating reality (ELECTRE) method to evaluate 10 kinds of energy power plants in five criteria. The plants includes the coal fired, solar-thermal, geothermal, biomass, nuclear, photovoltaic solar, wind, ocean, hydro and natural gas combined cycle power plants. The evaluation criteria reflects four aspects from the technology, economy, environment and society. The concrete criteria are efficiency, installation, electricity cost, CO2 emission, and land requirement. Finally, the multi criteria evaluations show that the hydro power plant in the renewable energy are the optimal schemes at present.

Analysis of the Thermodynamic Performance of Kalina Cycle System 11 (KCS11) for Geothermal Power Plant: Comparison With Kawerau ORMAT Binary Plant

Since the first geothermal power plant was built at Larderello (Italy) in 1904, many attempts have been made to improve conversion efficiency. Among innovative technologies, using the Kalina cycle is considered as one of the most effective means of enhancing the thermodynamic performance for both high and low temperature heat source systems. Although initially used as the bottoming cycle of gas turbines and diesel engines, in the late 1980s the Kalina cycle was found to be attractive for geothermal power generation [1, 2, 3]. Different versions (KSC11, KSC12 and KSC13) were designated. Comparison between Kalina cycle and other power cycles can be found in later studies [4, 5, 6]. Here we examine KSC11, because it is specifically designed for geothermal power generation, with lower capital cost [3]. We compare this design with the existing Kawerau ORMAT binary plant in New Zealand. In addition, parametric sensitivity analysis of KCS11 has been carried out for the specific power output and net thermal efficiency by changing the temperatures of both heat source and heat sink for a given ammonia-water composition.

The Role of State Policy in Renewable Energy Development

State policies can support renewable energy development by driving markets, providing certainty in the investment market, and incorporating the external benefits of the technologies into cost/benefit calculations. Using statistical analyses and policy design best practices, this paper quantifies the impact of state-level policies on renewable energy development in order to better understand the role of policy on development and inform policy makers on the policy mechanisms that provide maximum benefit. The results include the identification of connections between state policies and renewable energy development, as well as a discussion placing state policy efforts in context with other factors that influence the development of renewable energy (e.g. federal policy, resource availability, technology cost, public acceptance).

Improved Efficiency of Dye Sensitized Solar Cells Using Aligned Carbon Nanotubes

Dye sensitized solar cells (DSSCs) offer many advantages in comparison to their Si-based counterparts, including lower cost of raw materials, faster manufacturing time, and the ability to be integrated with flexible substrates. Although many advances have been made in DSSC fabrication over recent years, their efficiency remains lower than commercially available Si photovoltaic cells. Here we report improved efficiency of TiO2/anthocyanin dye solar cell using aligned arrays of carbon nanotubes (CNTs) as a counter electrode. Dense vertically oriented CNT arrays are grown directly on the counter electrode using microwave plasma chemical vapor deposition and a tri-layer (Ti/Al/Fe) catalyst. The resulting arrays are 30 micrometers in height and have a number density of approximately five hundred million per square millimeter. By directly growing the CNTs on the counter electrode substrate, electrical interface conductance is enhanced. The performance of both as-grown and N-doped (using a nitrogen plasma) CNT arrays is reported. The fabricated DSSCs are tested under AM1.5 light. Increased short circuit current is observed in comparison to graphite and Pt counter electrodes. We attribute this improvement to the large surface area created by the 3D structure of the arrays in comparison to the planar geometry of the graphite and Pt electrodes as well as the excellent electrical properties of the CNTs.

Aggregation Method of Multi-Criteria Evaluations in New and Renewable Energy Power Plants: A Case Study

The multi-criteria evaluation methods of complex systems such as the new and renewable technologies gradually spring up. The feasibility of energy power plants is evaluated and considered from many aspects, such as technology, economic cost and environment protection. However, the energy power plants’ ranking results in different methods or different weighs can be different. Accordingly, the sequencing results should be aggregated and analyzed, and then an integrated result should be given out. Aiming to get the specific evaluation result, 10 kinds of energy power plants, such as hydro, nuclear, wind, geothermal and biomass plants are considered and evaluated. The singular value decomposition method is employed to aggregate the evaluation results in grey relational method, PROMENTHEE II method, and other results from literature. The integrated evaluation result shows that the hydro and nuclear power plants are located on the first place and the renewable energy power plants have great potential development in the future.

Dynamic Modeling of a Wind Hydrogen System

Dynamic behaviors of an integrated wind hydrogen system have been modeled mathematically. It is based on a combination of fundamental theories of mechanics, thermodynamics, mass transfer, fluid dynamics, and empirical electrochemical relationships. The model considers wind hydrogen system to be composed of three subsystems, i.e., a wind generator, an electrolyzer, and a hydrogen tank. An additional pressure switch model is presented to visualize the hydrogen storage dynamics under a constant outflow condition. Validation of the wind hydrogen model system is evaluated according to the measured data from the manufacturer’s data. Then, using wind power as the primary energy input and hydrogen as energy storage simulated the power system. Finally, flow and electrical characteristics and efficiencies of each subsystem as well as the entire system are presented and discussed. The present model will integrate with fuel cell systems to realize the stand-alone renewable power generator in the future work.

Catalothermionic Power Generator Based on Internal Electron Emission in Ni/SiC Heterojunction Nanostructures

We report on the unusual properties of single-faced SiC metal-semiconductor heterojunction nanostructures manifested by the ability to atalyze the hydrogen oxidation reaction, and also maintain internal electron emission over the Schottky barriers. As a result a stationary current has been detected in the preheated nanostructure when exposed to the oxyhydrogen gas mixture flux. The structures maintain both the non-adiabatic and electron-phonon channels of energy transfer, and the results of studies indicate the possibility for a very efficient conversion of chemical energy released in the catalytic oxidation of hydrogen into electricity.

Design of Solar Assisted Community Biogas Plant

This study aims at providing a solution to the difficulty in the production of biogas in cold weather conditions especially during winters and in hilly regions where the temperature remains low throughout the year. As is well known biogas can be produced by anaerobic fermentation of organic materials with the help of bacteria [1]. Meynell [2] pointed out that the production of biogas becomes insignificant when the slurry temperature is less than 15°C. Such situations are usually faced in northern India, where the ambient temperature and, hence, the slurry temperature, in the winters drops below 15°C and hence improper digestion of slurry leads to poor biogas yield. This problem can be overcome by making the biogas plant solar assisted. The heat requirements of the digesters generally consist of three parts; (i) heat required for raising the temperature of incoming slurry for digestion; (ii) for compensating heat losses through the boundaries of the digester and (iii) for compensating losses that might occur in the piping between the heat source and the digester [3]. The required heat is provided from the collector which absorbs solar radiation and converts it into heat which is absorbed by a heat transfer fluid passing through the collector [4]. In this work, a biogas plant for a specified capacity has been designed. Based on the biogas plant dimensions and the average ambient conditions for a specified location, the rate of loss of energy was determined. A solar collector system has been designed to supply sufficient energy to maintain the slurry temperature of 35° C.

An Exergy-Based Framework for Assessing Sustainability of IT Systems

This paper proposes an exergy-based approach to evaluating the sustainability of different information technology (IT) systems. In reviewing existing standards around IT sustainability, we find that most of these metrics are based on energy efficiencies. Thermodynamically, these metrics imply sufficiency of a first-law analysis. In this paper, we show that such metrics based on the first-law of thermodynamics are necessary but not sufficient for evaluating the sustainability of IT systems. We discuss how — within the context of sustainability theory — exclusively relying on first-law metrics implicitly assumes a narrow set of system boundary conditions, and we show using an exergy-based life-cycle analysis that various classes of IT systems violate these boundary conditions. Thus, we suggest the need for metrics that include a second-law component as well as a life-cycle view of the IT system. Having identified such a metric, we demonstrate applicability of the framework for a sample IT system. We conclude by reflecting upon additional research needs and challenges associated with widespread implementation of such a framework.