水平轴风力机三维气动特性实验

以国外某公司的水平轴风力机产品为原型设计模型风力机，并搭建了风洞实验台，测定了风力机三维速度流场，为研究水平轴风力机关键气动问题做好准备，并初步获得风力机的进出口流场的实验数据。表明，所做的风洞实验基本反映了风力机的运行特点，捕捉到了叶片尾迹流动的基本特征，为进一步进行风力机的气动特性研究和设计高性能的水平轴风力机提供了保障。     

半导体催化光解制氢技术研究

氢能是一种新型高效洁净能源。本文介绍了颇有应用前景的光分解水制氢技术的原理,重点介绍了半导体光催化分解水制氢反应机理和技术方法。     

基于PLC的变频恒压变流量供水节能系统的研究与应用

针对传统供水系统能源浪费严重、自动化程度低等特点,设计开发了一种以PLC、变频器为核心构成的变频恒压变流量供水系统。介绍了该系统的节能原理、系统构成及工作原理、硬件、软件设计及系统优点,证明了变频恒压控制系统优越的技术性能和极其显著的经济效益,具有很好的推广应用价值和进一步的研究价值。     

Simulation and optimization of a LiBr solar absorption cooling system with evacuated tube collectors

Solar radiation is a clean form of energy, which is required for almost all natural processes on earth. Solar-powered air-conditioning has many advantages when compared to a conventional electrical system. This paper presents a solar cooling system that has been designed for Malaysia and similar tropical regions using evacuated tube solar collectors and LiBr absorption unit. The modeling and simulation of the absorption solar cooling system is carried out with TRNSYS program. The typical meteorological year file containing the weather parameters for Malaysia is used to simulate the system. The results presented show that the system is in phase with the weather, i.e. the cooling demand is large during periods that the solar radiation is high. In order to achieve continuous operation and increase the reliability of the system, a 0.8 m³ hot water storage tank is essential. The optimum system for Malaysia's climate for a 3.5 kW (1 refrigeration ton) system consists of 35 m² evacuated tubes solar collector sloped at 20°.     

Experimental and computational analysis on guide vane losses of impulse turbine for wave energy conversion

This paper deals with the detailed flow analysis of impulse turbine with experimental and computed results for wave energy power conversion. Initially, several turbulence models have been used in two-dimensional (2-D) computational fluid dynamic (CFD) analysis to find a suitable model for this kind of slow speed unconventional turbine. Experiments have been conducted to validate the CFD results and also to analyze the aerodynamics at various stations of the turbine. The three-dimensional (3-D) CFD model with tip clearance has been generated to predict the internal flow and to understand the effect of tip clearance leakage flow on behavior of the turbine in design and off-design conditions. As a result, it is found from the 2-D results that the comparison between computed and experimental data is good, qualitatively and the turbulence model, standard k–ε can predict the experimental values reasonably well, especially the efficiency of the turbine. Experimental results reveal that the downstream guide vanes are more responsible for low efficiency of the turbine and it is measured that 21% average pressure is lost due to downstream guide vanes. It is proved from the 3-D CFD model with tip clearance that it can predict the experimental values quantitatively and qualitatively. Furthermore, it is estimated from the computed results that the efficiency of the turbine has been reduced about 4%, due to tip clearance leakage flow at higher flow coefficients.     

Climate sensitivity of marine energy

Marine energy has a significant role to play in lowering carbon emissions within the energy sector. Paradoxically, it may be susceptible to changes in climate that will result from rising carbon emissions. Wind patterns are expected to change and this will alter wave regimes. Despite a lack of definite proof of a link to global warming, wind and wave conditions have been changing over the past few decades. Changes in the wind and wave climate will affect offshore wind and wave energy conversion: where the resource is constrained, production and economic performance may suffer; alternatively, stormier climates may create survival issues. Here, a relatively simple sensitivity study is used to quantify how changes in mean wind speed—as a proxy for wider climate change—influence wind and wave energy production and economics.     

Application of geographical information systems to rural electrification with renewable energy sources

This paper approaches one of the main problems of rural electrification: the choice of the most appropriate technology for each case. The main objective of this project is to apply Geographical Information Systems (GIS) to divide the research zone into areas in that are more appropriate for either conventional or renewable technologies. The approaches for choosing among the different technologies are usually technical and economic; these may be jointly considered by the leveling electric cost (LEC). Determination of the LEC is a complex task that requires knowledge of the capacity factor. This paper shows the conclusions of the technical and economic parameter analysis involved in the determination of the LEC for each technology. This analysis has allowed us to carry out proposals of improvement in the methodology of the GIS of rural electrification. The resulting GIS has been verified in the municipality of Lorca (Murcia, Spain).     

Computational analysis of performance and flow investigation on wells turbine for wave energy conversion

Wells turbine is a self-rectifying airflow turbine capable of converting pneumatic power of the periodically reversing air stream in oscillating water column into mechanical energy. This paper reports the computational analysis on performance and aerodynamics of Wells turbine with the NACA 0021 constant chord blades. Studies have been made at various flow coefficients covering the entire range of flow coefficients over which the turbine is operable. The present computational model can predict the performance and aerodynamics of the turbine quantitatively and qualitatively. The model also predicted the flow coefficient at which the turbine stalls, with reasonable accuracy.     

Photocatalytic degradation of pesticide contaminants in water

Photocatalysis has been proved to be an effective and inexpensive tool for the removal of organic and inorganic pollutants from water. Of particular interest in this context, in recent years, has been the complete photocatalytic mineralisation of a variety of pesticides into harmless products. The technique is now reaching the pre-industrial level, with several pilot plants and prototypes being operational in various countries. This paper reviews the major developments in the area, with special reference to the mechanism of the process involved, nature of the reactive intermediates and final products.     

Optimization of energy production system in the Dodecanese Islands

The ongoing depletion of the fossil fuels and the dependency of the economies on them have made the need for new sources of energy more obvious. Renewable energy sources (RES) can ensure the sustainable development of the communities, and especially of those in which RES are in abundance. This study deals with the exploitation of RES in the Dodecanese Islands. Specifically, it is examined the optimum percentage by which the renewable sources can participate in the energy production system. Three different scenarios are examined. The first scenario considers that the existent system should be used less than 75% for environmental reasons, in the second scenario, a minimization of the electricity production cost is sought without any environmental constraints, while in the third scenario, it is considered that the RES’ participation in the electricity production would be 30% at most according to the current legislation. The environmental impacts from the energy production are quantified and a comparison is made between the impacts resulting from the existing system and the system found from the first scenario, because this is the scenario with the highest penetration of the RES to the energy production system.